Top cover structure of power battery

Abstract

The invention especially relates to a top cover structure of a power battery, belonging to the field of energy storage devices. The top cover structure comprises a first electrode assembly, a second electrode assembly and a top cover piece, wherein the first electrode assembly comprises a first pole, a first sealing member and a first connecting block; the first pole comprises an upper section anda lower section; the materials of the upper section and the first connecting block contain a first matrix metal; the material of the lower section contains a second base metal; the upper section hasa step part; the lower section is connected with the bottom surface of the upper section; the top cover piece is provided a first pole hole; the upper section passes through the first pole hole; the step part and the lower section are located below the top cover piece; the first sealing member comprises a same-nature sealing part and a lateral extension part; a cylindrical sealing part sleeves theupper section; the lateral extension part is located between the lower surface of the top cover piece and the step part; the top of the upper section is connected with the first connecting block; andthe second electrode assembly is attached onto the top cover piece. The top cover structure of the power battery in the embodiments of the invention can effectively prevent the joint surface of the upper section and the lower section from cracking or even breaking.

Description

technical field [0001] The present application relates to the field of energy storage devices, in particular to a power battery top cover structure. Background technique [0002] In the non-aqueous electrolyte secondary battery, aluminum or an aluminum alloy that is insoluble in the non-aqueous electrolyte at the positive electrode potential is suitably used as a constituent material of the positive electrode pole. Copper, which is not alloyed with the negative electrode active material, is often used as a constituent material of the negative electrode pole. [0003] When the power battery is grouped, the busbar needs to be welded to the connection block of the positive electrode or the connection block of the negative electrode. Since the busbar is mostly made of a single material (such as aluminum or copper), the melting point of aluminum is lower than that of copper and the specific heat capacity is higher. , it is impossible to easily weld the copper and aluminum materi...

AI Technical Summary

Problems solved by technology

[0004] However, since the pole not only plays a conductive role in the top cover of the power battery, but is also used for fixing the first sealing member and the insulating member, it will be subjected to the extrusion stress of the first sealing member after assembly

These extrusion stresses will push the copper part and the aluminum part to the upper and lower sides of the top cover respectively. The above joint surface is cracked or even disconnected, thus causing liquid leakage, which is more likely to occur when the diameter of the pole is small

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