Tesla fire bring disaster to their share price volatility

I believe we have a concern about the developments in the Tesla electric car, it’s every action will cause strong reactions in the industry, unfortunately Tesla battery recently had a problem that people are most concerned about: safety, this month in American, a Tesla Model S electric vehicle battery module hit by fire. In Tesla this year became the focus of the automotive industry background, the case caused an uproar, Tesla shares soared this year, and therefore volatility. 

Local time on October 1, a Tesla Model S at the Washington State Kent (Kent) of road metal objects on fire after the collision. Then fire scenes photos and video widely disseminated on the Internet, causing concern and hot, and for questioning the safety of electric vehicles.

Tesla shares this year, an increase of about five times, thus “Tesla Tornado” famous. And this after the fire incident sharp fluctuations in stock prices, only 2 October afternoon in less than an hour, the stock price plummeted from $ 185.74 to $ 175.76. Landslide to 23, the stock was more than 10%, the stock had reached its lowest point around $ 168, which means a $ 2.3 billion market value evaporated.

In order to “fire”, October 4 Tesla CEO Aron • Musk (Elon Musk) on the blog published an open letter by the principles of interpretation of the safety performance of the Tesla Model S defense.

Musk noted, Model S at the time and chunks of metal objects collided with a large area of ​​the body damage. Later on the road near the scene and found a possible fall from the truck bent metal panels, which may be the culprit. In relative motion, the panel drill into the vehicle, piercing the Model S Body leveraged to form a hole diameter of 3 inches, while the body of the car to protect the car only a quarter-inch shell thickness, can not stop up to 25 tons penetration force. In crashing, the lithium battery fire. 

But Musk stressed that due to the early warning system to help car, Model S owners succeeded in escaping from the trouble spot. Front-end collision resulting in the battery module fires, Model S battery pack includes a total of the entire 16 modules, most mounted on the front of the car, separated from the interior of each module by fire apparatus. Ventilation holes on the battery pack makes the flame spray down along the road and away from the car. It also believes that compared with traditional fuel vehicles, electric vehicles are relatively low flammability, if a combustible fuel by the impact, the consequences will be more serious.

After publication Musk defended Tesla stock was back up to $ 180 level, to October 7 and even return to the $ 186 level. But October 8 Tesla shares plummeting to near $ 175 again, the day to close at $ 174.73, $ 194.50 from the highest point of this year’s significant gaps.

       Security issues can not be ignored in today’s focus on new energy development, power type lithium trends generally optimistic, but security problems have been an issue of great concern to everyone, I hope the first company can focus on this issue.

General Electronics Battery Co., Ltd. electric vehicle battery has been committed to the development, production, for consumers to create a safe, environmentally friendly batteries.

http://www.gebattery.com.cn

Note lithium battery of series and parallel

The power lithium battery in series and in parallel use, which sounds like a very simple, but to follow a few simple rules, you can avoid unnecessary problems. Lithium battery pack contains two parts: the lithium battery and lithium battery protection circuit.

   In the lithium group is more than a lithium battery in series, to get the required operating voltage. If you need a higher capacity and higher current, it should put lithium batteries in parallel. There are also a number of battery packs in series and in parallel with the combination of these two methods. A laptop battery may be the four 3.6V lithium-ion batteries in series, the total voltage reaches 14.4V; then, then strung together two batteries in parallel, so that the total power consumption of the battery pack can be from 2000 up to 4000 mA when mA. This connection is called “two-and four-string,” which means: put in parallel two by four batteries in series with the battery pack. Lithium-ion battery nominal voltage is 3.6V. Lithium ion polymer batteries, and other types of lithium, its rated voltage is typically 3.7V. If you want to get like this are not common 11.1V voltage, you have to put three such batteries connected in series. Series portable devices that require high power, usually by two or more batteries in series battery pack. Another problem with the use of high-voltage battery pack brings is likely to encounter situations where a section of the battery pack battery failure. It’s like a chain, the more series with the battery, there is higher probability of this situation. As long as a battery problem, its voltage is reduced. In the end, an “off” the battery may interrupt current delivery. And to replace the “bad” batteries is no easy task, because the new and old batteries are not mutually matched. In general, the capacity of a new battery is much higher than the old cell. With the decline of the operating voltage, it reaches the discharge end of the critical point faster than a normal battery pack, while its time dramatically shortened. Once the device is cut off due to the power supply voltage is too low, the rest of the cells remained intact as the battery is not able to send out the stored charge. At this time, the bad battery cell that also presents a great resistance, but also with the load at this time, if, then, will cause the entire chain of the battery output voltage will fall significantly. In one set of batteries in series, one section of the poor performance of the battery, like a blocked pipe plug, will have a huge resistance to prevent current flow in the past. Other batteries will short-circuit, which will reduce the terminal voltage to 3.6V, or disconnect the battery pack and cut off the current link. Performance of a battery depends on the battery group is the worst performance of the battery piece.

   In parallel in order to get more power, you can put two or more cells connected in parallel. In addition to the battery in parallel, another approach is to use larger size battery. Due to limited battery can be chosen, this approach does not apply to all situations. In addition, the large size of the battery is not suitable to make special batteries required form factor. Most of the chemical batteries can be used in parallel, while the lithium-ion battery most suitable parallel. Connected in parallel by four battery cells, the voltage is held 3.6V, and the current and the operating time is increased to four times. Compared with the cells in series, the parallel circuit in the battery, a high impedance or “open” Impact of the battery is small, however, will reduce the load in parallel to the battery capacity and shortening the operation time. This is like a three-cylinder engine is only started. Damage caused by a short circuit will be even greater, because, in the short circuit, faulty battery will quickly run out of other batteries in the battery and cause a fire.

When using such a series-parallel connection method, the design is very flexible, you can use a standard battery size to the rated voltage and current needs. It should be noted: the total power of the battery will not be because of the different connection method is changed. Power is equal to the voltage multiplied by current. For lithium-ion batteries, the series-parallel connection method is very common. The most common kind of battery pack is a 18650 (diameter 18mm, length 650mm), which is protected with the protection circuit board lithium battery, lithium battery protection board can monitor each cell connected together in series, so that its maximum The actual voltage is 14.4V. The lithium battery protection circuit (ie, lithium protection board) can also be used to monitor series with each section of the battery. When the number of cells in series, you must comply with the following basic requirements: to keep clean the battery connection point. When to use four batteries in series, a total of eight connection points (the battery to the connection point of the battery compartment, the battery compartment to the connection point of the next section of the battery). Each connection point is there is a certain resistance, if you increase the connection point, which may affect the performance of the entire battery pack. Do not mix battery, select the consistent performance of the battery. When the battery is low, replace all the batteries. When used in tandem, to use the same type of battery. Pay attention to the battery polarity. If there is a polarity of the battery installed backwards, it will reduce the whole string of battery voltage, rather than increasing voltage.

General Electronics Battery Co., Ltd. electric vehicle battery has been committed to the development, production, for consumers to create a safe, environmentally friendly batteries.

http://www.gebattery.com.cn

Electric car battery daily maintenance methods

Battery life is, battery repair just keep it reaches normal design life. To promote the product to any factor battery repair battery repair the damage with the new batteries, ensure that the battery life can be extended many times, these are not scientific, it is not realistic. Without any damage to the battery of any factors, have an impact on the battery life, the question is how to reduce the damage to the battery, how to reduce the impact on battery life, following a brief introduction of several electric vehicle battery daily maintenance method for your reference.

Lead-acid batteries have no memory, so the capacity to rapidly decrease was primarily sulfide batteries and “dehydration”, “loss of power” and for some reason, fear is the battery “power loss” Brown, batteries often “power loss” battery pole board easily injured, we found that up to 70 percent of the electric vehicle battery capacity to reduce high current (starting current) strain discharge electrode plate is caused (electrical 摩尤 its obvious), strain belonging to the battery electrode plates physical damage, this damage can not be repaired. Therefore, “every car, every charge” to ensure that there is always sufficient battery voltage has become inevitable.

Users generally thought, maintenance-free batteries do not add water, in fact, this statement is wrong. Maintenance-free battery charging and high-current discharge process generates heat, there will be a heat evaporation, although the process is very slow evaporation of water, but over time, the cumulative amount of water evaporation on can not be overlooked.

Electric car start clever force. Electric car start-up current is large, especially in high-power electric motor friction, higher starting current. It hurt a large current battery plates, the best way is like riding a bicycle after riding before you start, and then start the electric car power supply. Of course, many electric motor means no riding, which is no other way.

Quarterly on the battery deep discharge once. After the battery is bound to use for some time to sink some active substances, if not promptly activate the active substance is bound to cause some impact on the battery capacity, so often used in electric car, the battery should be done on a quarterly basis depth of discharge once.

Frequently observed charger is good or bad. New battery charging process is generally 6-8 hours, the charger will light green when fully charged, the charging time is too long if necessary to check whether the charger voltage protection device corrupted, corrupted if you need immediate replacement charger or vulnerable to charge a bad battery. Also, do not buy fast charger charger for fast charging battery plates have the same injury.

Long battery when not in use for at least a month to give the battery charging time. The aim is to prevent the battery from the battery caused by placing too long curing and “loss of electricity.”

Prevent the battery from prolonged sun exposure. Prolonged sun exposure can cause the battery temperature rises, so pay attention.

The above part of a more comprehensive description of the battery damage, repair, and maintenance of the relevant skills and knowledge, which is based on our years of experience and market feedback information written in simple language articles, layman understand at a glance. At the same time, we also sincerely reader from one side of the electric car battery repair techniques uncover the mystery, which is battery repair can take many methods, but not all damage to the battery are effective, curing illnesses and small battery restored effective; plate mild softening, short circuit, may be effective after a short break after every repair, as supernatural, as will the use of time is not long fallen into place; also some very serious damage to the battery, repair largely ineffective, introduction this knowledge is mainly to facilitate the reader’s understanding of the industry initially make the right choice on battery maintenance and repair.

After passing electric car batteries by battery manufacturers factory, battery life and performance depends in part on consumer use and maintenance.

(1) Matching charger and battery.

Electric car batteries are rechargeable bad, rather than bad, showing the importance of the charger and the battery match, there are two situations: First, the new parameters and battery charger provided by the manufacturer itself does not match, the charging voltage is too high and aggravated battery water loss, shortened life expectancy, more serious is the charge current drops to less than the current value of the conversion settings, battery temperature, charging current is further increased, the temperature rise much, resulting in thermal runaway cell expansion and deformation, and vice versa charging voltage is too low, the battery charge state owe a long period, not always part of PbSO4 conversion, resulting in sulfate, battery capacity drops, electric bikes continues the course shortened. Second, poor quality components charger itself, just started, fairly matched, as consumers charge and discharge cycles used. Charger itself due temperature, aging of components, resulting in the charging voltage and switching current drift, battery damage.

It is recommended that consumers and manufacturers of electric vehicles is best to buy a battery charger manufacturers supporting, not because it is cheap and filling joie de vivre of a bad battery, but not worth the candle.

(2) Often, replenish electricity.

Consumers using the nominal cycle life instructions usually have a misconception that one charge, the battery life is reduced once, so every time the battery power consumption, such as the protection voltage 31.5V to the controller began to supplement electricity , not knowing that not only can not protect the battery and shorten battery life. Because the positive active material is not strong PbO2 itself combined with each other, and the molar volume of PbO2 and PbSO4 are very different, more shallow depth of discharge, contraction, the lower the degree of expansion.

So remind consumers, where possible, the battery should charge it in time.

(3) Prohibited under undervoltage condition indicator shows continue riding. Some consumers after riding half way, the indicator displays the status of undervoltage take rest a re-ride some way, such great harm to the battery, the battery will discharge over serious salinization or lead generation branches crystal, short circuit the battery, affect life expectancy.

(4) electric bikes just starting, climbing, overloading should try to help.

(5) rain riding, switches and connectors should try to avoid getting wet, to prevent leakage.

Know more about some aspects of the knowledge about the battery lead-acid batteries for electric bikes maintenance and repair have positive side, through technical improvements compared with the great advantage especially to improve the colloidal technology, cost-effective lead-acid batteries and other batteries.

General Electronics Battery Co., Ltd. electric vehicle battery has been committed to the development, production, for consumers to create a safe, environmentally friendly batteries.

http://www.gebattery.com.cn

Lithium battery should become a mini-bombs aside venting

Has always been its high energy discharge stable and people of all ages, and thus established its dominance in the telecommunications, electronics fields. However, the past two years, but it has occurred more than cell phones, laptops bombings, the culprit is the lithium battery. This “diagnosis”, the lithium battery into the debate on the cusp. Why the sudden explosion of the battery will be good, or even kills come from? Improper use or the battery itself is a problem? No matter what, “lithium batteries” seems to have been branded a “suspected bomb” notoriety, how do we deal with it in the end it?

What are the conditions to have explosive

In order to ascertain the cause of battery explosion, we need to be clear - in the end what is the “explosion”?

Explosion in the usual sense, generally refers to the explosion of gunpowder, gas, etc., people always bang explosion impression, ablaze. Beijing Institute of Technology Professor Feng Shun Shan long been engaged in research and ammunition, he told reporters, “the explosion is a chemical reaction in a very short period of sudden and instantaneous release a lot of energy in the process.”

Potentially explosive chemical elements include carbon, nitrogen, oxygen, hydrogen, sulfur, etc. However, not only these elements but also, if it is normal to relieve the reaction process is not sufficient to constitute an explosion. According to experts, the explosion must have three conditions: the reaction process can release a lot of heat, the reaction is very fast, and to produce large amounts of gaseous products. For example, when explosives being large enough external energy effects, such as crashing or encountered when using detonators, will suddenly violent chemical reaction occurs in a short time, high temperature, high pressure gas, the formation of an explosion. 

Speaking of explosives, people always immediately think of the name of TNT, which is a high explosive, an organic compound with a benzene ring, the scientific name is called TNT, under normal conditions, TNT yellow powder or flaky scales. Per kilogram TNT explosion can produce 4.2 million joules of energy, which energy is enough to ruin a bridge or a house.

Lithium has the right material conditions constitute explosion

Control the various elements to form the desired explosive, and to analyze the composition of the reaction the internal lithium battery. Internal lithium battery in the end what chemicals it contains? They form explosive enough to do?

Ter laboratory safety testing expert Chinese Ministry Liu said, “Usually people say phone lithium-ion batteries, also known as battery pack or battery pack, which is mainly composed of batteries and protection circuit, in which the positive and negative electrodes of batteries , electrolyte, separator, shell composition. “

Currently a widely used cathode material for lithium cobaltate, lithium cobalt oxide will decompose under certain conditions, the separation of lithium ions, a negative electrode material is graphite, the molecular structure with many small space, which is a lithium-ion storage cells. The electrolyte is typically a mixed organic solvent which is commonly called the electrolyte of lithium hexafluoro phosphate salt. As the function of the insulating film is mainly separated positive and negative, to prevent short-circuit the poles of the contact, the current isolation of the porous polymer film, a material generally used in the film of the polyolefin microporous film is to make the lithium ions can pass through freely. When charging the battery, the lithium ion battery positive electrode through the electrolyte to the cathode movement, embedded in the porous carbon layer, the more negative the embedded lithium ion battery charge capacity is higher. Similarly, when the battery discharges, the anode embedded in the carbon layer of lithium-ion prolapse, and movement back to the cathode. This completes a lithium-ion battery charge and discharge process.

Elements from the inside of the battery, it already contains carbon, oxygen and electrolytes easy to burn, these substances are sealed in a small space, if certain conditions have entirely possible due to chemical reactions release heat and huge gas, it could explode.

But not to say that with these elements, they will explode. Professor, Department of Applied Chemistry, Harbin Institute of Technology, the lithium battery expert Shi Pengfei told reporters that “only under certain environmental conditions, the lithium ion electrolyte, isolate interactions occur between the membrane, complex changes occur until the cause explosions. “

Why high-temperature lithium battery explosion could bring

You can further questioning, in the end what kind of environment conditions require, the internal battery only abnormal situation? Reporter specifically ask Professor Sun Jinhua State Key Laboratory of Fire Science, China University of Technology. Professor Sun said, “If the improper charging, the lithium battery in a short time will produce a lot of heat, it will explode.”

Explanations for Sun Jinhua, Liu said further added, “is charging lithium battery cathode materials, such as lithium cobalt oxide or lithium manganese oxide, the state is unstable, it will decompose, releasing oxygen under high temperatures. Released oxygen and organic solvent electrolyte reacts to produce a lot of heat. Additionally, under certain voltage is applied, a solvent and an electrolyte itself may also react and emit a lot of heat, causing security problems. “

The heat generated is how? Internal battery in the end what changes have occurred? We can not be seen with the naked eye. But the researchers use certain techniques, but can clearly “see” the process of change within the battery. Dr. Wang Qingsong China University of Technology, the use of advanced micro-calorimeter for thermal reaction of lithium batteries were studied experimentally, the study found, lithium battery cathode active material, a negative electrode active material, electrolyte, such as under normal use and abuse will occur exothermic reaction.

Sun Jinhua said, “heat release, while the reaction gas pressure inside the system was continuously increases, causing the thermal expansion of the battery, the security measures in case of failure, including the potential risk of explosion.”

In addition, the phone call will cause the battery to heat for a long time, but also cause internal circuit and the earpiece fever, if you happen to use a counterfeit battery, could easily cause an explosion. Some would call when the phone is charging, when charging the phone battery will generate heat would have, if we continue to use it to call, then the heat will quickly upgrade, can easily lead to danger.

Crystal cut separation membrane can lead to an internal short circuit detonated

The chemical reaction within the battery is a slow process, the resulting heat accumulation is also a gradual increase process. In another case, a sudden increase in the heat instantaneously, that is shorted.

Under normal conditions, the insulating film inside the battery positive and negative electrodes spaced apart, forming a short circuit is not, however, in the case of over-charging, the insulating film may be cut, it may touch the poles.

Isolation between positive and negative film is how it was scratched? Liu said, “In the case of over-charging, lithium-ion cathode fewer and fewer are going to go negative, while the negative electrode of lithium-ion is increasing. To a certain extent, the negative electrode of lithium ions overflow generated dendritic crystals, crystal growth spread inside the battery, and then cut through the isolation membrane until the contact with the negative, so there has been a short circuit inside the battery. “this is happening because of a short circuit in the battery, so you can call an internal short circuit. At this time, instantaneous release of a large amount of heat, electrolyte boiling, “boom” is heard on the bursting of the battery case.

 ”Breakdown” phenomenon without a conductor can cause a short circuit

Crystal scratched isolation membrane, actually played the role of “conductor” of communicating the positive and negative. In fact, even with no conductor, in the case of over-charging, the positive and negative poles may be in direct contact, this is called “breakdown”, the same short-circuit may occur.

It should be the concept of over-charging for clarification. The so-called “overcharging”, some people think that is super-long charge, in fact, this is a misunderstanding. Sun Jinhua said, “does not refer to overcharge the charging time is too long, but rather refers to the range of the standard lithium battery voltage exceeds the normal work.” In general, lithium-ion battery voltage is between 3.7 volts to 4.2 volts when charging, the voltage will be higher poles, if to continue to charge 4.2 volts, which is over-charged. If the voltage is high to a certain extent, it will form a “breakdown.”

According to experts, when the poles of the voltage is high enough, a strong electric field in the middle of the insulating material will lose its insulation properties, a conductor, thereby connecting the positive and negative poles, which is a dielectric breakdown. “It is not difficult to understand, even if there are two electrodes in the air, if the voltage is very large, it may also occur breakdown, the naked eye is the formation of a spark.” Therefore, when the voltage of the lithium battery poles when large enough, may be directly connected to the positive and negative poles entirely, this is actually a special kind of short circuit.

Communicating the positive and negative metal shavings cause a short circuit

In the case of over-charging or discharging, may lead to the accumulation of heat or cause a short circuit, then, if nothing is done, that is placed in normal circumstances, a lithium battery explosion will happen?

The answer is yes, there is also the risk that may occur, the Japanese company’s notebook burning is an example. When the company’s battery explosion, battery manufacturers initially remained silent, tight-lipped, and later under repeated requests from the media, it felt compelled to respond. Finally, manufacturers explained that, because the battery batteries contain metal shavings, the result of external short circuit caused the battery, so it sparked an explosion.

Manufacturer’s interpretation is reasonable? Without charging the battery itself, without short-circuit discharge will occur? Sun Jinhua analysis said, “If the batteries contains metal shavings, may lead to a short circuit completely, even in the normal state, may also lead to the positive and negative connections. “

Visible, the production process of the battery must also be highly restrictive. If the manufacturing process is rough, the assembly process appears some metal burrs, etc. can stay hidden membrane folds, one unfortunately, will make positive and negative poles to a close contact.

Battery reserve a “gas outlet”

For the problem of increased pressure within the battery, lithium batteries must have an internal pressure to ease security devices, which need to mention the pressure relief valve.

"Pressure relief valve means in the battery casing set a relatively thin section, which can effectively prevent the battery accidentally burst, it’s like a pressure cooker of the valve as well." Liu Road.

If the pressure relief valve is designed, when the internal gas then expands moderately relief valve opens, the gas can be smoothly discharged from the relief valve, but with a portion of the energy. If the pressure relief valve design is unreasonable, when the pressure increases would not open, then the internal pressure increases, increasing the danger at any time explode.

It should be noted that the pressure relief valve is not more “sensitive” as possible, if it is very easy to open the case, the outside air will come. Because the internal electrolyte boiling point, melting point is low, it is easy to react with the air, this time, there will also burn or explode.

"Fuse" can effectively prevent a short circuit

In daily life, some have used the phone for a long time, and still use the battery damage, and some young people like all kinds of metal ornaments, keys, etc. together with the phone, do you not know this would short-circuit the left risks. In another case, if the battery is subjected to a collision or impact, it may happen to cause a short circuit within the battery, the same explosion.

Short-circuit problem is very troubling, so be sure need protection circuit within the battery. Daily equivalent circuit protection circuit fuse. Liu said, “a qualified protection circuit should have such a function: When the detected charging voltage is too high, or when the battery is fully charged, you can cut off the charging circuit when the detected current or charge current is too large, you can limit. current or cut off the current. “

Such as mobile phones and laptop use lithium products, should also be charged and discharged its internal limit circuit. For example YD / T 1591 “mobile handset chargers and interface requirements and test methods” stipulates that “mobile phone charging current should be limited within the specified range, when the phone detects that the charging voltage is too high, you should cut off the charging circuit.” It is understood that some battery manufacturers are working on lithium battery protection circuit and more, increasing the safety factor of the battery.

Greatly reduce the risk of a new generation of lithium battery explosion

As the liquid electrolyte easily release heat, some battery manufacturers began to study other electrolytes to replace it. Has now successfully developed a lithium-ion polymer battery.

A liquid electrolyte and a lithium-ion battery type, the polymer lithium ion battery instead places the solid polymer electrolyte, the polymer may be “dry” and can be “colloidal”, the most current product the use of polymer gel electrolyte.

Since the solid electrolyte instead of a liquid electrolyte, polymer lithium-ion battery will not leak occurred, combustion and explosion risks are greatly reduced. Liu said, “polymer lithium-ion batteries can also be done using polymer cathode material, the energy will be higher than the current liquid lithium-ion battery more than 50%.” In addition, the polymer lithium-ion battery voltage, charge and discharge cycle life and other aspects than lithium-ion batteries has increased. Based on these advantages, the next generation of lithium-ion polymer battery known as lithium-ion batteries.

General Electronics Battery Co., Ltd. electric vehicle battery has been committed to the development, production, for consumers to create a safe, environmentally friendly batteries.

Contact :  Benny , SALE ,  Gebattery , Tel.  86-755-81762725,  81762726, 8 1762727, 23315028, 2331308  or e-mail : sell (at) gebattery (dot) com (dot) cn. http://www.powbat.com.cn                                        http://www.gebattery.com.cn

Pollution problem is the current focus of the battery industry topics

Contaminated sludge at current basic concern of the whole society has been greatly improved, mainly because of the sewage sludge sedimentation governance and flotation machine had suspended solids into sludge aeration dominant, but we also to face up to is electroplating sludge, as well as emissions of heavy metals in the sludge, such as battery sludge, as new energy development, the pace of development of electric vehicles has exceeded our expectations speeds, reducing the demand for oil, while . There have been such a problem, the problem is that the battery industry pollution is relatively serious, there are a few of the pollution in 2009 because of pollution from the battery industry caused a more serious harm.

Interpretation of the main battery pollution in the end, what does?

What is the battery, we often say that the general principle is that these batteries Festival, which fills the cavernous lead with a stereotype as a negative stereotype filled with lead dioxide as cathode, with 1.28% of sulfuric acid as the electrolyte. When charging the electrical energy into chemical energy, and the discharge energy is converted to chemical energy. When discharging the battery, the metal lead is a negative electrode, an oxidation reaction, is oxidized to lead sulfate; lead dioxide positive electrode, reduction reaction occurs, is reduced to lead sulfate. Jinan marking machine factory mainly produces laser marking machines and laser coders 2010 laser marking machine price big discount when using DC battery charging poles are generated lead and lead dioxide. After the power is removed, it returns to the state before the discharge, the chemical composition of the battery. Lead-acid battery is able to repeatedly charge and discharge of the battery, called the secondary battery. Its voltage is 2V, usually three to use lead-acid batteries in series, the voltage is 6V. Use of the car is six lead-acid batteries in series into a 12V battery pack. Lead-acid batteries in use for some time to add distilled water, keeping the electrolyte containing 22 to 28% sulfuric acid.

Generally above analysis, we can clearly see that the battery is a major component of lead elements, but is also a lead element relatively high pollution elements have been integrated into the water, with the social demand for the rapid growth of the battery, the battery manufacturer’s earnings are booming, plus a lot of battery enterprises have settled down to some relatively remote counties, these counties surface will bring some economic growth, while managing environmental governance is not very perfect, pollution caused by various factors, management of national battery industry vulnerabilities exist, also contributed to last year’s blood lead pollution incidents occur frequently, so that pollution also has a great relationship with the economy, especially the country’s strict rules pollution projects, the first is with large profit margins, so many business owners to invest in such pollution, big profit margins of the project on the need for strict regulation of these polluting projects to prevent pollution of time.

Batteries, chewing gum foil to make fire

ready to test tools and cut into strips of aluminum foil.

Fold the foil two pairs in the fold of the cut a small triangle.

The tin strip cut a good pick in the 5th battery terminals.

Tin strip in the middle begins to smoke, then flames burning appeared.

The middle section of the narrow ends slightly wider strip of chewing gum tin pick in section 5 battery terminals, after a few seconds, even in the middle of a fire breaking the foil. Recently, some circulated on the Internet and battery with aluminum foil to make fire the dynamic map, users were stunned by this amazing phenomenon, also questioned whether the real picture. Two seemingly unrelated supplies really easy to fire it? Yesterday, the reporter did a hands-on experiments.

   Experimental tool

   Scissors, gum foil,

   1.5V alkaline batteries

   Experimental procedure:

   1 Remove the foil pack of chewing gum to start, cut width was 5 mm, 10 mm, about 9 cm long strip of several;

   2 would cut a good note two pairs of folded tin in a small cut on the fold of the triangle, but do not cut, leaving a 5 mm or so “narrow ace”, thus forming an intermediate long narrow slightly wider at both ends Article.

   3 with the tin side of the strip of tin inwardly, one end of the positive electrode of the battery 5, the other end of the negative electrode of the battery to observe the results.

   The experimental results

   Among the different success rates of different width

   Experiment one: Take a length of 9 cm and a width of 5 mm strip of tin, tin tin strip with one end of the positive battery at the other end of the negative battery. Soon obviously feeling the heat tin strip, cut a good middle note “narrow ace” at the beginning of smoke, then flames burning occurs, finally breaking the middle, the whole tin strip was completely burned, only the residual layer of tin. Reporter repeated the experiment several times, each time to make fire success.

   Test two: a length of 9 cm and a width of 10 mm strip of tin, with the method of operating the same. At this time the temperature rises rapidly at both ends of the tin strip, more hot than the width of 5 mm piece of paper, but in the middle of the “narrow ace” is just a wisp of white smoke coming out, you can clearly see the black scorch marks, but whole tin paper does not burn.  

   Experiment III: The length and width are the same, but do not cut out the middle strip of tin triangle, under the same experimental conditions, tin strip both ends quickly becomes hot, and more hot, reporters had to drop a note.

   Principle

   Foil can be conductive, connected to a battery short circuit

   What happened between the foil and the battery, why would produce sparks? Reporters ask the lecturer, School of Physics, Central South University, Huang Shengxiang. 

   Huang said it was too junior high school physics principles. “Packaging chewing gum one side is conductive foil, it is cut into strips to make an equivalent of the wire, the resistance of tin is small, the access ends of the positive and negative electrode foil, a current loop is formed, which is usually said short-circuit. “

   Why should the middle of tinfoil cut narrow it? “This is because the small cross sectional area of ​​the narrow place, the ends of the resistance will be smaller than the wider, in the case of the same voltage, the voltage equal to the resistance multiplied by the current, where the current intermediate resistance smaller maximum temperature rise to the fastest Finally, burning up. “

   Huang also reminded, in order to successfully make fire, foil width and “narrow smb” width is critical, too narrow in the smoke easily snapped, too wide may only smoke no fire. Foil width of about 5 mm, “narrow tip of the” best fit about 2 mm. “Directly to the width of the strip consistent access to battery positive and negative, not only can not make fire, still may cause a rapid increase in the temperature of the entire strip of tin, burn your fingers.”

http://www.gebattery.com.cn Hotline:+86-755-81762725-616 - GEB Official Site. Offer custom batteries, custom battery packs, Lithium ion batteries, LiFePO4 batteries, polymer batteries, LiMnNi batteries, LiNiMnCo batteries, lead acid batteries, battery chargers, battery testing equipment, welder machine, rc batteries, diving light batteries, ebike batteries, gps batteries, PCB, PCM, BMS system.

Based on lithium-ion battery charging circuit design USB interface

Keywords: USB interface, lithium-ion battery, charging circuit

lithium-ion battery and USB Interface Overview

Lithium-ion (Li-ion) batteries, lithium battery for short <http://bbs.dianyuan.com/tech/battery>, is the increasing popularity in recent years, the use of a new type of battery, with small size, light weight, high capacity (high energy density), self-discharge rate and advantages such as no memory effect, but it also has some fatal flaw: the charging and discharging of the more stringent requirements, can not overcharge and over discharge, or likely to cause irreversible damage to, in short circuit, overcharge and other extreme cases there may be an explosion dangerous.

General lithium single nominal voltage 316 ~ 317V, charging, generally require the use of limited pressure limiting law, the first constant current charging, ie a current constant charging current by low magnification national standard charge is 0.2C (arbitration charge standard), the maximum does not exceed 1C; while charging the battery voltage is gradually increased as when the battery terminal voltage reaches the termination voltage 412 ± 0105V, should be changed to constant voltage constant current charging small current (about 011C) charge, the state general called trickle charge state. The charging current based on the saturation level of the batteries, with the charging process continues to gradually decrease, and when reduced to 0101C, that the charging is terminated.

USB interface is in English UniversalSerialBus abbreviation, Chinese meaning is “Universal Serial Bus.” It is a new field in the PC interface technology applications. USB uses a 4-pin plug as a standard plug to connect with external devices. In this four-pin plug, there are two pins for data communication lines, while the outer two needles compared to an external device to provide power. According to the USB specification, each USB port should be able to provide 500mA output current; provided by the USB host or hub with a power supply of the USB interface, the connected peripheral end of the minimum available voltage is 4.5V, while the USB bus powered hub can provide should be a minimum of 4.35V. worth noting that, although the USB specification defines the current limit provided shall not exceed 015A, but in fact the current USB port output is often more than a few amps.

As can be seen from the above analysis, the use of USB interface for battery charge, the current terms should be enough, the key is how to control the size of the current. In addition, the use of a minimum of 4.35V voltage USB interface to the typical requirements for 4.2V lithium battery when charging, only a small margin on the voltage, which makes the charging circuit voltage drop becomes extremely important, is the difficulty of design.

PC-based USB interface charging circuit design

2.1 Option One

Figure 1 is a market of some of the “USB charging cable,” the internal circuitry. The main principle is to use the maximum current limit resistor, a diode voltage drop (approximately 0.7V) about the USB interface 5V output voltage down to about 4.2V rechargeable lithium battery then. This circuit has a simple, low-cost advantage, but the disadvantage is obvious: the charging current and charging voltage and battery status vary in different USB interface vary, basically can not grasp, in many cases the battery is likely sufficient dissatisfaction (charging voltage of less than 4.2V), but sometimes it may overcharge and damage the battery. This circuit has some internal lithium battery protection circuit for sound acceptable, but for ordinary lithium batteries, there are certain dangers.

2.2 Option II

Figure 2 is a practical USB Li-ion battery charging circuit by MAX1551 / 1555 constituted. MAX1551 / 1555 is designed and manufactured by MAXIM USB single lithium battery charging chip, 5-pin thin SOT23 package, allowing the USB port or wall adapter 3.7V ~ 7V AC input voltage range. Internal chip also has a temperature limit circuit.

When For this circuit, when connected to a USB port, but no AC wall adapter DC power, the charging current is set to 100mA (Max). This is not required in the case of the communication port, allows the power from the USB port or power charging. When DC power is turned on, the charging current is set to 280mA (typ), while the USB input interface is automatically cut off. If both inputs are non-voltage input, the circuit is automatically turned off, then the reverse leakage current of the battery is less than 5uA, no external diode to prevent battery leakage losses occur.

When the battery voltage is lower than 3V, will enter 40mA charge current is limited to a pre-charge mode (trickle charge state), only when the battery is charged to 3V than when entering the normal charging mode (100mA or 280mA). This mode protects the deep discharge battery. Figures 3 and 4 are used as the DC power supply box curve USB interface input voltage and the charging current of the battery.

In addition, the MAX1551 “, / POK” is used to indicate the input power is turned on (when the input voltage is 3.95V output low); while for MAX1555 “, / CHG” is used to indicate the state of charge (when the charge current is greater than 50mA output low).

2.3 Option III

It should be said, Option II is a safe, relatively comprehensive consideration of all aspects of USB rechargeable lithium battery and perfect solution. The disadvantage of this solution is that: the charging current is fixed at about 100mA or 280mA, especially when the USB interface power supply, only the charging current of 100mA for larger capacity batteries, charging takes quite a long time. Another disadvantage is that there is no charge timer function, the charge can not be ended or not artificially controlled. Figure 5 is another practical USB interface charging circuit design using the LTC4053 as the core, while maintaining the advantages of the two programs again to solve the above problems.

LTC4053 is Linear (Linear) has introduced a USB interface can be powered directly from a lithium-ion battery termination constant current / constant voltage linear charger IC with Independent Timing for 10-pin MSOP package. May consist of a single lithium battery USB interface for charging directly, or you can allow the use of a wall AC adapter as the power supply of DC power. Required input voltage range is 4.25V ~ 6.5V. Includes an on-chip power MOSFET. The most important feature of this chip is that it allows designers to set their own charging current and charging time, charging termination voltage already preset to 4.2V.

In Figure 5, the charging current by PROG LTC4053 (7) pin resistor R to the set, which is calculated as: R = 1500V / ICHG, for example, to set the charging current is 500mA, then R = 1500V / 015A = 3kΩ. The maximum charging current can be set to 1125A. Figure 6 is a graph of the charging current and battery voltage.

LTC4053’s TIMER (4) capacitance C pin is used to set the charging time is calculated as follows: T (h) = C (uF)? 3 / 011uF. When C = 011uF, the charging time of 3 hours.

This circuit has a similar program two pre-charge mode trickle charge mode and battery-specific fault detection function: When the battery voltage is lower than 2.48V, with 10% of full scale current trickle charge; If this state lasts more than a quarter of the total charge time is that the battery has been damaged and stop charging cycle.

LTC4053 itself has a perfect temperature measurement and compensation adjustment function that allows users to safely larger current charging thereby greatly reducing the charging time, charging current and Figure 7 is a graph of the ambient temperature. Similarly, when the LTC4053 no voltage input, the circuit can automatically cut-off, the reverse leakage current is less than 5uA, no external diode to prevent battery leakage, avoid battery depletion.

Conclusion

There is no doubt that in these three scenarios, features the third option is the most perfect, the flexibility of its design application is also the biggest, but more pins, the device cost of the chip may also be higher than other programs . In practice, we can according to the actual situation of use, cost, etc. to choose different options to meet different requirements. With the development of integrated circuit technology, the constant introduction of new devices, we believe there will be more and better USB charging scheme appears.

General Electronics Battery Co., Ltd. electric vehicle battery has been committed to the development, production, for consumers to create a safe, environmentally friendly batteries.

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Lithium-ion battery cycle performance factors affecting Discussion

The importance of the cycle performance of a lithium ion battery without saying; additional terms of the macro, longer cycle life means less consumption of resources. Thus, the factors that affect the performance of lithium-ion battery cycle, every problem associated with lithium industry personnel have had to consider. The following are a few that may affect cell cycle performance factors, for your reference.

Material Type: The choice of materials is the first factor affecting the performance of lithium-ion batteries. Select a poor cycle performance materials, processes and then reasonable to prepare for further improvement, batteries can not be guaranteed circulation is bound; choose a better material, even made ​​a slight problem follow the cycle of poor performance may not too outrageous (once played grams of lithium cobalt oxide is only about 135.5mAh / g and analysis of lithium batteries, 1C although hundreds of times diving but 0.5C, 500 times more than 90%; anode batteries have open after a black graphite particles batteries, the cycle performance of normal). From the material point of view, the performance of a full cycle of the battery, the positive electrode and the electrolyte solution cycle characteristics after the match, the cycle properties of the electrolyte and the negative electrode after the two match, the less one to decide. Poor cycling performance, one may change the crystal structure of the cycle can not proceed so fast lithium deintercalation one hand, since the active substance may be unable to generate the corresponding electrolyte membrane caused by dense, homogeneous active substance SEI side reactions with the electrolyte leaving prematurely excessive consumption thereby affecting electrolyte circulation. In the design of the batteries, if the material is poor cycle performance of a selection electrode is recognized, the other electrode is preferably no need to select the cycle performance material waste.

Positive and negative compaction: Positive and negative high compaction, although the energy density of batteries, but also to reduce the cycling performance to some extent. From the theoretical analysis, the greater the compaction, the greater the equivalent structural damage to the material, the structure of the material is the basis for a lithium-ion battery can be used; addition, the positive and negative high compaction is difficult to ensure than the batteries the high liquid retention amount, and the amount of fluid is guaranteed to complete the normal cycle batteries or more cyclic basis.

Moisture: Excessive moisture will be positive and negative electrode active material and side reaction occurs, and thus affect the structure of the destruction cycle, while too much water is not conducive to the formation of the SEI film. However, while difficult to remove traces of water, traces of water can be guaranteed to some extent, the performance of batteries.

Coated film density: Consider the impact of a single variable density film cycle is almost an impossible task. Film density inconsistencies or differences in the capacity to bring either batteries or winding difference laminated layers. With the same capacity of the same material type batteries, the lower the density of the film corresponds to an increase or a wound layer or layers laminated layers, corresponding to the increase of the electrolyte membrane can absorb more to ensure circulation. Considering the thinner the film density can be increased rate performance of batteries, and the bare core pole piece of baking will be easier to remove water, of course, the density of the coating film is too thin, the error may be difficult to control when the active substance large particles may also be coated, rolled a negative impact, more layers means more foil and diaphragm, in turn means higher costs and lower energy density. Therefore, when assessing the need to balance considerations.

Negative excess: Excess addition causes a negative initial irreversible capacity to consider the impact of the deviation and the coating film density than the impact on the cycle performance is also a consideration. For lithium cobalt oxide and graphite system, the negative cycle of graphite become “short board” one of the more common. If negative excess is not sufficient, batteries may not analyzed before cycling lithium, but hundreds of times the loop structure is minimal but the positive and negative changes in the structure was severely damaged but not completely positive reception thus providing lithium-ion analysis of lithium, resulting in over-capacity early fall.

Electrolyte volume: Produce insufficient amounts of electrolyte circulation affect three main reasons, one less than the amount of fluid injection, the second injection fluid volume is adequate, but despite the lack of time or aging infusion due to the positive and negative electrodes and other causes excessive compaction is not sufficient, the third is with cycle batteries inside the electrolyte is consumed. Note inadequate and insufficient fluid volume fluid volume Paul wrote, “electrolyte deficiencies on the performance of batteries” before and therefore not repeat them. On the third point, the negative electrode and the positive and negative electrolyte particular microscopic matching dense and stable performance of SEI formation and performance of the visible eye, both for circulation of the electrolyte during the consumption rate. Incomplete SEI film on the one hand and the electrolyte can not effectively prevent the occurrence of negative side effects and thus consume the electrolyte, while the SEI film with defective parts will be re-circulated in order to generate the SEI film and electrolyte depletion reversible lithium source . Whether circulating hundreds or even thousands of times the batteries or both diving for dozens of batteries, the electrolyte is sufficient and if the first cycle after cycle has been consumed electrolyte, the electrolyte increased ownership is likely to be some enhance the cycle performance degree.

Test objective conditions: Testing during charge-discharge rate, cut-off voltage, the charging cut-off current, tests overcharge and over discharge, the test room temperature, the sudden interruption during the test, the test point and the contact resistance of batteries and other external factors that will or less impact cycle performance test results. In addition, the sensitivity of different materials to the above objective factors varies, uniform testing standards and understand the characteristics of the common and important materials should be sufficient daily use.

To sum up: The same principle as the barrel, the factors affecting the performance of batteries circulation among many, the ultimate decisive factor is a number of factors in the shortest board. Meanwhile, among these factors, but also have a reciprocal influence. In the same materials and made ​​capacity, the higher the circulation, often means lower energy density, to find exactly the point of integration to meet customer needs, try to ensure the consistency of batteries made ​​of party is the most important task lies .

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