Lithium-ion batteries have attracted a lot of attention because of their large capacity, high operating voltage, safety and stability, and lack of safety effects. And caused a worldwide research end. Therefore, lithium-ion batteries have quickly developed into industrial applications and are widely used in portable devices such as mobile phones, video cameras and laptop computers.
The development process of lithium-ion batteries:
Today, mobile communication devices such as cell phones and tablets have become the most popular electronic products. The battery is the only high energy storage device in the mobile communication terminal, which provides power protection for the operation of the terminal. At the same time, the communication network is growing, and the number of mobile communication will be the focus of the communication industry and the electricity industry. In addition, the work of the station is more powerful, flexible and easy, which leads to higher and higher demands on the battery.
Because lithium-ion batteries have not been on the market for a long time. So there is still a lot of room for improvement. As a new type of power source, lithium-ion batteries still have a long way to go to improve their performance. Although lithium-ion batteries have many advantages, they also have many disadvantages. For example, the cost of the battery is high, the current cannot be charged and removed, and the reimbursement is low.
Therefore, in the future, the improvement direction of the lithium-ion battery is:
1. Reduce costs.
2. Also improve battery power.
3. Also understand weight reduction and battery miniaturization.
Safety issues of lithium-ion batteries
Obviously, with the development of lithium-ion battery technology, it will have a wide application prospect. However, reports of fires and even explosions caused by lithium-ion batteries have become frequent in recent years, and their safety issues have caused widespread concern.
There are the following main conditions:
1. The general regime of quality control, inspection and quarantine has also strengthened the control of battery quality. During maintenance and inspection, it was found that there are several problems with the battery products themselves.
2. The contents of the packaging and the label of some products are not regulated and some products are not stored or put on the brand, brand, name of the manufacturer, company address, etc., which disappoints the consumers when purchasing.
3 Battery power is designed to have a short usage time.
4. Some products do not exceed the safety limit and short circuit protection, which can damage the battery and mobile phone terminal.
5. The low temperature discharge performance is not enough, resulting in poor outdoor use in the winter of the mountains, and there may be a short period of use or even a serious failure of the start.
Causes of accidents with lithium-ion batteries:
The safety of lithium-ion batteries is related to the electrolyte:
Lithium-ion batteries have a safety hazard, which is mainly caused by a chemical reaction between the electrode and the electrolyte. The solvent of the electrolyte solution is an organic carbonate compound. They are very reactive and very flammable. The positive electrode material of a battery in a charged state is a strong oxidizing compound. The negative electrode in the charged state is an energy reducer.
In the event of abuse, such as overcharging, overheating and short circuit, the positive electrode is often of poor stability and quickly releases oxygen. . Carbonates react easily with oxygen, giving off a lot of heat and gas. The heat generated will accelerate the destruction of the positive electrode, increase the oxygen concentration and promote another exothermic reaction.
At the same time, the function of the power to reduce the negative electrode is close to that of the lithium battery, it burns as soon as it enters the oxygen atmosphere and ignites the electrolyte, separator, etc.
Therefore, the storage of lithium-ion batteries can be divided into two categories:
First, the closed lithium-ion battery system is not damaged, but there are potential risks. mainly related to the thermal stability of the material.
Second, the battery system has been destroyed the electrolyte burns and the oxygen produced in the battery or oxygen outside the battery can cause a fire or even explode.
The safety of lithium-ion batteries is related to battery capacity:
In addition, the safety of lithium-ion batteries is related to the capacity and size of the battery. A battery with a higher capacity generally corresponds to a higher heat release rate. Larger batteries are more difficult to remove heat, and heat is more likely to build up, causing heat to escape. In general, the total energy stored in a lithium-ion battery is suitable for its storage. As the power of the battery increases, the volume of the battery increases and its heating efficiency worsens. Chances of accidents will increase significantly and safety issues will become more important.
However, high-capacity lithium-ion batteries are definitely the next step in development. So, how to manage battery quality is what we need to do.
How to check battery quality?
Currently, in addition to the part I EEE standards for the testing of the entire battery system (design, production, testing of finished products, etc.), other standards are standard acceptance standards, that is, test items specified by the standard. For example, IEC62133, UN38.3, UL1642, etc. It is used to recycle the battery during use and visible damage, to ensure the safety of the product under these conditions. The advantage of this type is that the case is clear and the performance is good. Just run a lab test on the finished battery to determine if the standard is met.
