Lithium battery cover plate and lithium battery welding process comprising same

Abstract

The invention discloses a lithium battery cover plate and a lithium battery welding process comprising the same, and relates to the field of lithium batteries. The lithium battery cover plate comprises a cover plate, a pole is arranged at the top end of the cover plate, a liquid injection hole is formed in one side of the pole, an aluminum shell is connected to the bottom end of the cover plate, awelding starting point is arranged between the cover plate and the aluminum shell, and one side of the welding starting point is connected with a final welding point. According to the invention, through the power difference during welding, the cover plate without an explosion-proof valve is welded with on shell, and the welding process parameters of the battery cover plate and the shell are designed, so that the welding strength of the cover plate and the shell of the battery is weaker at a certain section. Under the condition that large energy is generated in the battery, the battery shell is firstly exploded in the area with weak welding strength, the battery is protected from further damaging other batteries or systems, and an explosion-proof valve is not arranged on the cover plate any more, so that the structure of the cover plate of the battery is greatly simplified, the cover plate is convenient to machine and form, the cost is reduced, and the risk that other foreign matters puncture the explosion-proof valve is also avoided.

Description

technical field [0001] The invention relates to the field of lithium batteries, in particular to a lithium battery cover plate and a lithium battery welding process containing the structure. Background technique [0002] In recent years, lithium batteries have developed rapidly and are more and more popular with the public. People's daily life is increasingly inseparable from lithium batteries, such as mobile phones, computers, toys, cars, etc. Lithium batteries are becoming popular Unimaginable speed is gradually replacing lead-acid batteries. [0003] However, in the application process of lithium batteries, lithium-ion batteries quickly generate a large amount of energy under thermal runaway conditions such as overcharge or internal short circuit. In daily use, in order to quickly release the energy of the battery, it is generally used An explosion-proof valve is added to the top cover of the battery. The opening pressure of the explosion-proof valve is less than the wel...

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Problems solved by technology

[0003] However, in the application process of lithium batteries, lithium-ion batteries quickly generate a large amount of energy under thermal runaway conditions such as overcharge or internal short circuit. In daily use, in order to quickly release the energy of the battery, it is generally used An explosion-proof valve is added to the top cover of the battery. The opening pressure of the explosion-proof valve is less than the welding tension between the battery top cover and the shell. When the pressure of the battery increases rapidly, the explosion-proof valve explodes to protect the safety of the battery pack and the system. Valve battery production costs are high, the production process is complicated, and the efficiency is low, which is not conducive to the market promotion of lithium-ion batteries

[0004] Chinese patent CN204424325U discloses a battery cover plate and a lithium-ion battery containing the cover plate, wherein the battery cover plate includes a cover plate body, and the cover plate body is 0.8 mm thick. In the case of the internal structure of the battery, by using a 0.8mm battery cover plate, the internal space of the battery is improved, the liquid injection volume and liquid injection efficiency are improved to a certain extent, and the electrochemical performance of the high energy density battery is improved. Since the lithium battery cover plate is not equipped with an explosion-proof structure, it is very easy to explode when the battery is overcharged or short-circuited, and its risk factor is extremely high

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