A lithium battery that has passed the acupuncture test does not mean that the power lithium battery is safe!

A lithium battery that passes the acupuncture test does not mean that the power lithium battery is safe. With the reduction of new energy subsidies, lithium batteries have also regained the attention of automobile companies. BYD launched a brand-new 'blade batteryAccording to reports, insiders of CATL said that BYD’s blade batteries are not necessarily 100% safe. Passing the acupuncture test for lithium batteries does not mean that the safety of power lithium batteries exceeds 300 safety test methods for power lithium batteries. Among them, the 'acupuncture test' is recognized by the industry as the highest safety guarantee. The principle is the result of'using a simulated bare cell to be pierced by an external sharp object to cause thermal runaway'. BYD put together a ternary lithium battery, a lithium iron phosphate battery and its latest blade battery for a comparative experiment of 'acupuncture test'. The results showed that the ternary lithium battery burned violently during the test, and the surface temperature exceeded 500 degrees Celsius. The lithium iron phosphate battery has no open flame, no smoke, and the surface temperature is 200-400 degrees Celsius. The latest BYD blade battery has no open flame or smoke, and the surface temperature is 30 to 60 degrees Celsius. Lithium iron phosphate batteries are easier to pass through needles, not because of advanced technology, but because the material itself has good thermal stability, and the ternary lithium battery has a higher energy density. Acupuncture does present challenges, but not impossible. In order to achieve real market security, it is necessary to ensure it through various levels of security systems, rather than through a test. In other words, a battery that passes the needle stick test is not necessarily 100% safe, and not performing the needle stick test does not mean that the battery is unsafe. Ningde Times already has technology that can pass the acupuncture test of high-energy-density ternary lithium batteries, and has passed the acupuncture test of TUV and Shenzhen TUV certification laboratories respectively. Ningde Times still supports the cancellation of the acupuncture test according to the new national standard and hopes The industry focuses on security issues at the entire system level. 'In order to achieve real market security, it needs to be guaranteed by various levels of security systems, not through a test. When adjusting battery cell and module tests, the new national standard focuses on strengthening battery system thermal safety, mechanical safety, electrical safety, and functional safety requirements. In particular, the standard adds thermal diffusion tests for battery systems. This test Obviously, it is required that after a single battery cell is thermally out of control, the battery system will not catch fire or explode within 5 minutes, so as to reserve a safe escape time for the occupants. Improved methods of acupuncture project 1. Conductive agent and adhesive: After the needle is short-circuited, the conductive agent, adhesive and electrolyte react violently and release a lot of heat. Currently, the DSC method is used. It is an effective method to select the type of conductive agent and adhesive according to the initial temperature of decomposition and the heat of reaction to reduce high-temperature heat generation. 2. Battery structure design: When manufacturing power lithium batteries, consider adding an appropriate positive electrode. The gap between the negative electrodes can improve the ductility of the separator, and at the same time, an explosion-proof valve should be added to it. The cover plate on the top of the battery can prevent explosion and a large amount of electrolyte leakage, and increase the possibility of the battery passing through needle sticks; 3. Separator: In the power lithium battery, the separator is mainly used to separate the positive and negative electrodes of the battery to prevent A short circuit occurred between the two pole contacts. The closed cell temperature of the diaphragm and the rupture temperature of the diaphragm have a decisive influence on whether the battery can pass acupuncture items. It is necessary to control the battery separator to maintain a lower closed cell temperature and a higher membrane rupture temperature, and to develop PE and PP composite membranes, and ceramic separators are the development trend and direction of the separator. 4. Electrolyte: The electrolyte used in power lithium batteries is a combination of conductive lithium salt and organic solvent. These organic solvents have low flash points. When the electrolyte in the power lithium battery comes into contact with the air, it is easy to burn. The addition of flame retardant additives can improve the stability and safety of the battery itself, and is an effective method to increase the penetration rate of needle penetration. Passing acupuncture is not equal to the safety of the power lithium battery, and not performing the acupuncture test is not equal to the safety of the battery: the safety of the power lithium battery is mainly manifested in the thermal safety, mechanical safety, electrical safety and functional safety of the system He also believes that acupuncture single battery cell is not only the safety of the battery cell, it is also similar to the ignition test of the flammability of gasoline and diesel, completely ignoring the protective effect of the fuel tank. Under actual conditions, there will be no needle stick injury to the battery cell. The blunt puncture and squeeze at the bottom of the battery pack are more practical test methods. Disclaimer: The articles published on this site are all from the Internet and do not represent the views of this site. If there is any infringement, please contact to delete WeChat: Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact delete One: The imitation mother-of-pearl layer diaphragm can improve the impact resistance of lithium batteries.