The structure of lithium battery explosion-proof valve is mostly a through-hole processed on the cover, a step is set on the through-hole, an explosion-proof film is installed on the step, and the explosion-proof film and the cover step are laser welded to achieve battery sealing, but laser welding is easy to produce air holes or false welding, resulting in battery leakage or external gas entry, and the process defect rate is high. Moreover, the weld is corroded by electrolyte or the weld is loosened during the use of lithium battery, resulting in liquid leakage or external gas entry, which is a safety hazard.
Explosion-proof valve of lithium battery
Lithium batteries are mainly used to score, welding explosion-proof film as lithium battery explosion-proof device, when the battery heats up the internal gas expansion of the battery, the pressure increases to a certain degree when the moment of scar or explosion-proof film off welding, rupture, deflate the pressure, thus avoiding battery explosion. Lithium battery explosion-proof device structure to achieve full consistency is more difficult, and this explosion-proof device to deflate the start pressure value is large, so that in the event of an abnormal battery can not immediately deflate the pressure, resulting in lithium batteries explode.
Lithium battery explosion-proof valve is the use of positive temperature coefficient thermistor in the temperature of the higher the resistance value increases and does not conduct the working principle, can be felt by the positive temperature coefficient thermistor in the lithium battery temperature reaches a predetermined control temperature when the lithium battery current circuit cut off, to improve the safety of the use of lithium batteries.
The role of lithium battery explosion-proof valve
(1) explosion-proof valve whose coil shell not only has the role of gas explosion pressure isolation system explosion, and the gas explosion energy transfer has a blocking effect, higher safety performance. Particularly suitable for the transmission of flammable and explosive media or special series of products dedicated to explosive hazard sites, different environments and fluids should be channeled to choose different explosion-proof level of explosion-proof valves.
(2) automotive lithium battery explosion-proof valve is a breathable, waterproof, explosion-proof auto parts accessories, currently used more in new energy electric vehicles. Automotive lithium battery explosion-proof valve will be waterproof breathable film and explosion-proof valve function into one, not only has the traditional explosion-proof valve, reduce blast damage function, while having waterproof breathable function.
(3) power lithium battery cover with high temperature resistance, high insulation, high sealing and good safety performance, because the lithium battery in use may produce high temperature and high pressure gas, if not discharged outside the lithium battery may explode and cause serious safety accidents, so the battery cover manufacturers in the design of the cover will be equipped with explosion-proof system, in the case of excessive pressure inside the battery cell, explosion-proof system will automatically open pressure relief, to prevent the phenomenon of explosion.
The role of lithium battery explosion-proof test box
Lithium battery explosion-proof test box is mainly used for lithium battery new product development or daily testing of lithium battery performance, mainly for battery overcharge and overdischarge, charge and discharge test, the battery will be placed in the explosion-proof box, external charge and discharge tester. For the operator and the instrument for protection.
Design lithium battery explosion-proof box, explosion-proof box door not only as a test battery entrance and exit, observe the performance test conditions, more important function for the lithium battery explosion as a leakage surface, the release of lithium battery explosion generated by the impulse wave. Lithium battery explosion-proof box wall shall have the ability to resist the blast shock wave, can limit the destructive effect of the explosion within a certain range, stainless steel plate is mainly with the function of explosion-proof wall.
Lithium battery explosion-proof test chamber structure using a two-layer design: internal SUS material with Teflon tape + outer box cold-rolled plate baking paint treatment; SUS has better high-temperature resistance than the iron plate, the test chamber with Teflon tape inside can effectively prevent corrosion, insulation, flame retardant and easy to clean. Therefore, the box structure needs to be scientifically designed, for example, lithium battery explosion-proof design and automotive full-plate metal structure of the same, automotive crash test considered the overall results.
Lithium battery box in the production process needs to test the airtightness of the lithium battery box to determine the waterproof and dustproof ability of the lithium battery box, the test needs to be inflated to the inside of the box and test the internal pressure of the box, and then achieve the purpose of testing the airtightness of the box, but the lithium battery box is equipped with an explosion-proof valve device on one side of the device, explosion-proof valve device with multiple fine holes, fine holes can flow with the outside air, so in the box Therefore, when testing the air tightness of the box, it is necessary to effectively seal the explosion-proof valve to ensure the accuracy of the test.
