Battery Cap Assembly Multi-Tab Welding Integration
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Solution Overview
Problem
Cylindrical secondary batteries face challenges in increasing output power due to limited volume, making it difficult to enhance capacity and reduce internal resistance, particularly in welding electrode tabs to the current interrupt device (CID) or can.
Innovation Solution
A cap assembly with a novel structure that includes a cap plate, current interrupt device (CID), vent plate, sub-plate, middle plate, and insulator, featuring a receiving groove on the middle plate to securely connect electrode tabs, reducing internal resistance and allowing for a multi-tab structure without increasing battery resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of tabs is increased to reduce resistance and increase output power, then the battery's output power and capacity increase, but the welding process complexity and difficulty increase significantly
Solution Approach 1:
The patent merges the current interrupt device (CID) and the cap assembly into a single integrated structure. The CID is positioned between the cap plate and the electrode tabs, with its plate serving as part of the cap assembly structure. This integration allows multiple tabs to be welded to the CID plate simultaneously in a unified welding process, reducing welding complexity while enabling increased number of tabs for higher output power
2Reliability
If the number of tabs is increased to reduce resistance, then the battery's internal resistance decreases, but the manufacturing difficulty of welding multiple tabs increases
Solution Approach 1:
The CID plate serves multiple functions: it acts as the cap assembly structure, provides a common welding surface for multiple electrode tabs, and functions as the current interrupt device. This multi-functionality allows multiple tabs to be welded to a single universal surface (the CID plate) rather than requiring separate welding processes for each component, thereby reducing manufacturing difficulty while maintaining low internal resistance through multiple tabs
3Quantity of substance
If the battery volume is increased to accommodate more tabs, then the capacity and output power increase, but the battery size becomes larger
Solution Approach 1:
The patent utilizes the vertical dimension by stacking multiple electrode tabs in a layered arrangement within the limited battery volume. The CID plate provides a central hub structure that allows tabs to be arranged in multiple layers and orientations, effectively increasing the number of tabs and battery capacity without significantly increasing the overall battery volume. This dimensional arrangement maximizes space utilization
Data Source
AI summary
A cap assembly of a secondary battery is provided. The cap assembly includes: a cap plate; a current interrupt device (CID) under the cap plate, the CID including: a vent plate under the cap plate, the vent plate including a vent protruding downward and to be deformed when internal pressure of the secondary battery is increased; and a sub-plate under the vent plate and connected to the vent; a middle plate between the vent plate and the sub-plate and electrically connected to the vent plate through the sub-plate, the middle plate having a receiving groove to receive the sub-plate; and an insulator between the vent plate and the middle plate.