The safety of lithium-ion batteries is a complex and comprehensive problem. The biggest hidden danger of lifepo4 battery safety is the random internal short circuit of the battery, which will cause on-site failure and cause thermal runaway. Therefore, the development and use of materials with high thermal stability is the fundamental way and the direction of efforts to improve the safety performance of lithium-ion batteries in the future. We need measures to prevent, summarize the measures to prevent the explosion of LifePo4 batteries are as follows:
1. Improve the thermal stability of LithiumIron Phosphate battery materials
①The thermal stability of cathode materials can be improved by optimizing synthesis conditions at China LiFePO4 battery factory, improving synthesis methods, and synthesizing materials with good thermal stability;② The quality of SEI film formation directly affects the charge-discharge performance and safety of lithium-ion batteries. The treatment of carbon materials and the use of spherical or fibrous carbon materials can help improve the quality of Lifepo4 battery SEI film;③ The use of lithium salt with good thermal stability and a solvent with a wide potential stability window can improve the thermal stability of the battery. Adding some high boiling point, high flash point and non-flammable solvents to the electrolyte can improve the safety of the lithium-ion energy storage battery;④The type and quantity of conductive agent and binder also affect the thermal stability of the battery. The binder and lithium react at high temperature to generate a lot of heat. Different binders have different calorific values. Fluorine-free binders are used instead of PVDF, the thermal stability of the lifepo4 home energy storage battery can be improved.
2. Improve lithium-ion battery overcharge protection capability
In order to prevent overcharging of lithium-ion batteries, a dedicated charging circuit is usually used to control the charging and discharging process of the battery by chinese battery manufacturers, or a safety valve is installed on a single battery to provide a greater degree of overcharge protection; Secondly, a positive temperature coefficient resistor (PTC) can also be used, and its mechanism is that when the lifepo4 battery heats up due to overcharge, the internal resistance of the battery is increased, thereby limiting the overcharge current;A special separator can also be used. When the temperature of the separator is too high due to an abnormality in the battery, the pores of the separator will shrink and block, preventing the migration of lithium ions and preventing the overcharge of the lithium-ion battery.
3. Prevent the short circuit of the lifepo4 battery
For the diaphragm, the porosity is about 40%, and the distribution is uniform. The diaphragm with a pore size of 10nm can prevent the movement of small particles of positive and negative electrodes, thereby improving the safety of lithium batteries;The insulation voltage of the separator is directly related to the contact between the positive and negative electrodes. The use of a composite separator with a large difference between the thermal closure temperature and the melting temperature can prevent the lithium-ion battery from thermal runaway. The surface of the diaphragm is coated with a ceramic layer to improve the temperature resistance of the diaphragm, prevent the contact between the positive and negative electrodes, and ensure the safety of the battery packs.
4. The importance of lithium battery BMS
BMS is a lithium battery management system. Lifepo4 battery BMS main function is to detect various state parameters of the power battery, including cell voltage, total voltage, current, temperature, etc., and collect data through the analog front end to perform SOC estimation and battery balance. The BMS lithium battery management system is mainly used in electric vehicles, electric boats, and electric instruments and equipment with lithium ion batteries as the power system. Current and other parameters are monitored in real time, and corresponding cell balance management, charge and discharge protection control, heating and cooling management, and fault information alarms are provided.
- China Lithium Battery Supplier are often used to real-time display of total battery voltage, total battery current, single battery voltage, minimum single battery voltage, average voltage, single internal resistance, temperature, equilibrium state, capacity, etc.
- On-line measurement of the total voltage of the lithium battery pack and the voltage of the single cells, at the same time, analyze the differences between the single cells and automatically perform voltage equalization, which can effectively reduce the performance degradation of the battery pack caused by the performance degradation of individual cells, so that the service life of the lifepo4 battery pack is close to the design life of the battery;
- The safety LiFePO4 battery module has powerful functions. Each module monitors the voltage, internal resistance and balance management of 12 lithium batteries and the temperature of 1 channel. It adopts downward installation and adopts two-wire acquisition to improve the voltage and internal resistance test accuracy;
- Convenient parameter setting, lithium ion battery voltage upper and lower limit alarm setting, temperature upper limit alarm setting, current upper limit alarm setting, voltage unbalance, internal resistance maximum upper limit alarm setting, SOC initial value setting, rated capacity, charger control, etc.;
- The main monitoring chip-level real-time Ethernet, 10/100M adaptive LAN interface, automatic crossover for sending and receiving, can be directly connected to the optical fiber local area network (information network/data private network/automation network, etc.);
- The monitoring software can display AC status, charger running status, single lifepo4 battery voltage, internal resistance, etc. in real time. Multi-level user operation permissions can be set, and functions such as real-time viewing of alarm information, historical data curve reports, and printing can be performed.