Analysis of causes of explosion of lithium battery

Analysis of causes of explosion of lithium battery

The author has been in the battery market for very long time and found a phenomenon: many people are afraid of lithium. Base on knowledge of superficial lithium batteries, I will discuss the pros and cons of lithium batteries here.

The main thing for everyone now is to worry about the burning and explosion of lithium batteries. As far as the current lithium battery industry is concerned, the explosion caused by the main cause of the battery core itself has been very low. After all, the factory has tested by aging and so on. Unless it is a very low-level factory, the products of the regular company will not appear, so there is no need to discriminate against the type of battery. However, the incentives caused by changes in external conditions are the main ones, such as overcharge, over discharge, external impact, high temperature, etc., so the current prevention method is to do the line protection design, reasonable structure and preventive measures. The purpose of posting is to tell everyone that the choice of lithium battery should be cautious. First, you must have a full understanding of the lithium battery you are about to use, and use it reasonably to be shocked.

First, the battery burns, explodes, according to the results of the on-site analysis, the reasons involved in the battery, personal understanding has several points:

1. Internal short circuit (mostly soft package large monomer): structural or process defects lead to the insertion of the ear, the diaphragm package is too small, burrs, diaphragm discount and so on. The ear interpolation often appears in a thick battery and the structure connected in parallel. The insulation of the pole ear is not in place. In the subsequent process, the protective plate or the use process is likely to cause an internal acute short circuit and thus burn or explode (internal short circuit: this is the individual I have a deep understanding. At that time, more than 2K of this kind of battery was scrapped, which is a design defect - the abnormal nature is internal acute short circuit), but now this situation is almost rare, unless external factors.

2, external short circuit: 1AH below the battery short circuit caused by post-combustion explosion is rare, usually there is bulging or simply blow the ear, personal analysis of the power battery or large-capacity mobile phone battery short circuit caused by the short-circuit. This involves improper use of the customer - when the metal case is installed, the insulation of the ear is not taken into consideration, and the battery smoke is abnormally burned at the installation site; the power battery is also often inadequate in structural fixing measures (considering the problem), and the battery pack is used during the user's use. Shaking causes the battery's external insulation protective film to damage or the connection wire to be damaged, eventually causing short-circuit combustion.

3. Overcharged explosion: This is the most dangerous, and the company is most afraid of appearing, but it will occasionally appear. From the situation of understanding, there are two points: a, the user does not use the matching charger as required, thus destroying the protection circuit and the user often charges the battery when it is not limited, this situation is not difficult to blow. b, battery matching Unreasonable and the protection board fails, in this case, it will also be a mess... a single battery is the same.

4. The above 3 points are relatively common, comprehensively: structural design considerations and users according to the specification is the main direction to avoid product burning or explosion, I believe that the current major battery manufacturers have a very reasonable improvement Measures, personally feel that the development of safer materials is the king of lithium battery safety.

Second, the battery burns, explodes, according to the results of on-site analysis, involving improper use, the individual understands as follows:

1. Frequent deep charge and discharge: Lithium batteries have almost no memory. Many friends like to use the lithium battery or lithium battery digital products, they like to use the power to a little (protection board protection) and then charge, but in the eyes of many people, this is also a way to activate the battery. In the use of lithium batteries, we call the recharging of the used power as deep charge and discharge.

In fact, deep charge and discharge is a major misunderstanding when many people use lithium batteries. Scientists have concluded through experiments that the number of deep charge and discharge is proportional to the battery life in the case of other environmental conditions, and multiple charge and discharge. Will cause the battery life to end prematurely. The lithium battery that has a long service life is extremely likely to cause the battery to swell and cause an explosion.

2, over charge and discharge and charge and discharge current is too large. This situation is often occurred when the protection board design is unreasonable and charging, we often like to charge the device after the battery is fully charged, so that your equipment can the resistance time is longer, but what many people don't know is that the long-term overcharge

In addition, the over-discharge situation will cause serious damage and damage to the performance of the lithium battery. Seriously, it will cause extreme conditions such as explosion. Therefore, the battery is fully charged, and it has inserted into the charger. Eventually, it will become a tragedy. At the same time, we also need the current of the charger and the general current load of the electric appliance during charging and discharging. The excessive current load can easily cause the internal short circuit of the battery, thereby destroying the lithium ion and causing the safety hazard of the circuit. Similarly, for charging the charger voltage is the same. Therefore, we should also pay attention to see if the charger is qualified when using the charger. However, after many accidents, the manufacturers finally got the action. For most of the manufacturers, the protection devices, especially the electronic digital products, have added double protection or multiple protections to avoid this situation. However, the enhancement of users' own consciousness is still very important. Lithium batteries are extremely sensitive to temperature. If they used below freezing point for a long time, they may have a great impact on the battery life. Long-term exposure to overheated environment will greatly reduce the life of the battery. Seriously, the internal pressure will increase and cause an explosion. Even if there is no explosion, the battery will quickly scrapped in high heat. I feel that some cases are unfortunate because of the pool explosion. Most of the reasons for the death caused by the high temperature of the working environment.

With so many words coded, I thought about where to say, and my hands are sour. Lithium-electric project as an old technology that has been over 30 years old, the formal brand production department already has very mature commercial technology, which is enough to ensure the safety of the battery under normal conditions. And has been tested in practice, so if we are good at using Our battery does not pose too much safety hazard to us. Here are some suggestions for safe use of lithium batteries:

1. Use qualified charger: Charging time is the high incidence period of lithium battery explosion. The original charger or the qualified charger produced by the big manufacturer can ensure the safety of the battery more than the compatible charger;

2, the use of reliable batteries: try to buy regular manufacturers battery or market-known brand batteries, do not save money to buy "second-hand goods" or "parallel imports", such batteries may be repaired, not as reliable as the original battery.

3, do not put the battery in extreme environment: high temperature, collision, etc. are important incentives for battery explosion, try to keep the battery in a stable environment, away from high temperature.

4, reasonable assembly and maintenance: Many people like to buy second-hand batteries recombination batteries, and some people are "daring and careful" to buy their own DIY assembled batteries. However, improper assembly and mishandling are also prone to accidents, especially the choice of battery protection board, the arrangement and selection of good protection board components and the protection of the proper layout of the printed PBC are very important, and the damage of protection often becomes the battery killer. The chief culprit in the tragedy.

Finally, the author also briefly summed up several methods to share with you to help you extend the life of the battery and prevent extreme situations such as explosions:

1. Normal use of your battery. Lithium battery has no activation after leaving the factory. Normal charging and discharging are the best activation process for the battery.

2. When the mobile device is charging, the power controlled at 10% to 90%, which is beneficial to protect the battery life.

3. Avoid operating the battery under conditions of overheating or undercooling.

4. The battery should stopped immediately after it scrapped to prevent dangerous situations.

After reading this post, hoping we do not worry about one single part and if there is something wrong with the above-mentioned matters, please help to correct me and supplement it.

The page contains the contents of the machine translation.