Battery Top Cover Post Assembly for External Tab Welding
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Solution Overview
Problem
Secondary batteries face issues with internal short circuits and high heat generation due to laser welding slag and ultrasonic welding chips, leading to safety hazards and reduced cycling performance.
Innovation Solution
A secondary battery top cover design with through holes allowing tabs to pass through and connect externally with electrode contact regions, eliminating internal connections and enhancing heat dissipation through large post areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser welding and ultrasonic welding are used to connect posts and tabs inside the battery, then electrical connection is achieved, but welding slag and chips cause internal short circuits and safety hazards
Solution Approach 1:
The patent extracts the harmful welding operations from the internal battery space and relocates them to the external top cover assembly. The post is connected to the tab outside the battery shell, eliminating the risk of welding slag and chips causing internal short circuits while maintaining electrical connection functionality.
Solution Approach 2:
The top cover assembly serves as an intermediary component between the battery shell and the tab connection. It provides a dedicated space for welding operations outside the battery, acting as a mediator that isolates harmful welding byproducts from the internal battery environment.
2Reliability
If multiple welding connections are used to connect posts and tabs, then electrical connection is established, but contact resistance increases and heat generation becomes high under high current
Solution Approach 1:
The patent merges the post and tab connection into a single integrated welding operation on the top cover, rather than using multiple separate welding connections inside the battery. This reduces the number of contact interfaces and minimizes cumulative contact resistance, thereby reducing heat generation under high current conditions.
3Reliability
If tabs are connected inside the battery shell, then electrical connection is achieved, but the connection process is complex and requires internal assembly operations
Solution Approach 1:
Instead of connecting the tab to the post inside the battery shell as in conventional designs, the patent inverts the connection sequence by first attaching the post to the top cover externally, then connecting the tab to the post outside the shell. This reversal simplifies the assembly process and eliminates the need for complex internal assembly operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Eliminates internal short circuits and thermal runaway, reduces contact resistance, and improves cycling performance through rapid heat dissipation and temperature uniformity.
Implementation Method 1
the tab is electrically connected with the electrode contact region outside the shell through laser welding
Data Source
AI summary
The present disclosure relates to a secondary battery top cover and a secondary battery. The secondary battery top cover comprises a top cover piece, a post and a connecting assembly, wherein the top cover piece is provided with a through hole; the post is mounted in the through hole; and the connecting assembly is arranged between the top cover piece and the post, and is used for fixing the post onto the top cover piece. The post has at least one through hole and an electrode contact region, the at least one through hole being configured to allow a tab inside a battery to pass therethrough, and the electrode contact region being configured to be in electrical contact with the tab that passes through the at least one through hole. In the secondary battery top cover of the present disclosure, at least one through hole is provided in the post, such that a tab is welded to the post outside a case, which eliminates an internal short circuit of a battery that is caused by welding slag or welding filings, etc. generated by internal welding of the battery, and also eliminates associated thermal runway.