Short circuit test:
Standard requirements: Battery short circuit test includes one short circuit test and module short circuit test. The short output time of one battery is 10min, and the output resistance is not more than 5mΩ; during the safety battery short circuit test, there should be no explosion or fire.
Analysis and analysis of test results: When testing a small battery of the same supply battery, the short-circuit resistance is 2.7mΩ, the short current is large, and a large amount of gas flows out of the safety valve and electrolyte out. The short-circuit current of the module is several times higher than the current short-circuit current (a short circuit of 100Ah is almost 4000A). The battery pack reacts more strongly, releasing a lot of heat that melts the plastic shell of the battery pack, causing severe deformation. Combustion usually occurs in the system of the module short circuit, mainly because of many reasons: the insulating material of the metal connection part between the batteries is not enough decay retardant, combustion occurs at high temperature, igniting energy resources.
The protective cover of the plastic shell of the battery is not bad, which burns at high temperature and heats the battery the safety valve is strong, and the high temperature of the battery is generated in a short time -circuit cannot be released in time, causing the electricity to run, causing the battery to explode, fire and so on: the electrolyte is a flammable liquid, easy to burn at high temperatures, adding heat burning the fire, it can improve the security of the energy bank (the performance of the burning bank will be reduced), and the addition of the sale will be appropriate. If the battery still suffers from fire and explosion after eliminating the above problems in the test, a thorough investigation will be done on the cause such as electrolyte, electrode material and process.
Current problems and recommendations: It is recommended to install hardware protection (PTC) for each power bank (especially small capacity cylindrical batteries) if there is a small circuit, the current is large, a will cut off the circuit immediately, and after the battery is recovered, the circuit will be automatically connected to protect the battery. For laminated power batteries, it is recommended to add a fuse between several batteries.
Currently, the fire safety test specified in the international mandatory standard is a regular test. Due to the continuous development of battery technology, further research and analysis is required. Therefore, some companies provide high test requirements for their products in the production process, such as immersion, fire, shot, vibration and other R & D tests.
Water immersion test:
Test method: Put the fully charged battery module into salt water for discharge test (water depth, salt water input and discharge current should be provided by the company). During the test, there must be no explosion or fire.
Analyze test results: This test usually shows the condition of an electric transport vehicle or a flooded power bank due to spontaneous flooding. As the battery is immersed in water, higher levels of protection are introduced for the battery. If the battery protection is not good, water entering the battery will make the battery short: the safety valve and the electrode are weak parts. Once the salt water is immersed in the battery, making a short time, the battery will give a lot of heat and gas, which will cause the salt water to produce many bubbles or even boil.
Fire test:
Test method: Put the complete battery module in the light and burn it (the light and the time of the fire should be provided by the company). During the test, there must be no explosion or fire.
Evaluation of test results this test usually shows the ignition of the vehicle due to poor conditions and a hot battery. If the power battery explodes or catches fire, it will increase the ignition of the car, which will pose a serious risk to the safety of passengers. During the test, due to the high temperature outside of the power battery, high-quality materials are made for the heat insulation of the power battery shell, and for the heat of the solution.
Shooting test:
Test procedure: Place the complete battery module in a vertical position for the discharge test and use a gun to fire vertically on the electrode plate (the company should provide the current, firing conditions and firing time). During the test, there must be no explosion or fire.
Check the test results: The test often shows that bullets hit the battery of electric vehicles moving in bad conditions such as terrorist attacks. Shooting a battery will cause the battery to short out, giving off a lot of smoke and heat. If the heat is not released in time, it can be followed by combustion, explosion and other things.
Vibration test:
Test procedure: Fix the fully charged battery module on the vibration table according to the vehicle condition for discharge (vibration condition and current should be provided by the company). During the test, there must be no explosion or fire.
Review the test results: This test usually shows the vibration produced by the vehicle traveling on different roads. Under the vibration condition, the active material in the battery pack may fall off the battery electrode, welding contact, and terminal, external wiring, solder joint, etc. can break and collapse, causing an external or internal leak bitter.
