Prismatic Battery Cap Assembly for Reliable Side-Terminal Welding
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Solution Overview
Problem
Existing side terminal type secondary batteries have complex internal structures and welding defects due to the coupling between terminals and current collectors, which affects energy density and reliability.
Innovation Solution
A secondary battery with an improved cap assembly structure, featuring a cap plate, insulator, and terminal portion with a terminal post that protrudes towards the current collection plate, enhancing the coupling and adhesion between terminal and current collector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a side terminal type secondary battery is used to simplify terminal structure, then device complexity is reduced and energy density is improved, but welding defects occur due to coupling issues between terminals and current collectors
Solution Approach 1:
The terminal structure is segmented into distinct functional parts: the cap assembly (cap plate + insulator) and the terminal portion (sub-terminal + terminal plate), with the terminal post as a separate coupling element. This segmentation allows independent optimization of each component and simplifies the overall assembly process while ensuring reliable welding through the dedicated terminal post structure.
2Reliability
If terminals are coupled to current collectors to enable electrical connection, then electrical conductivity is improved, but welding defects occur due to coupling issues
Solution Approach 1:
The terminal post acts as an intermediary element between the cap assembly and the current collector. This intermediate structure provides a dedicated welding interface that ensures reliable electrical connection while eliminating direct coupling issues between the cap assembly and current collector, thereby reducing welding defects.
3Quantity of substance
If internal space is maximized for high energy density, then productivity and energy density are improved, but terminal structure becomes more complex
Solution Approach 1:
The cap plate and insulator are merged into a single integrated cap assembly, and the sub-terminal and terminal plate are merged into a unified terminal portion. This merging reduces the number of separate components and simplifies the internal structure while maintaining high energy density through efficient space utilization.
Data Source
AI summary
A secondary battery includes: a prismatic case having at least one end open; an electrode assembly accommodated in the case; a pair of current collection plates at both ends of the electrode assembly in the longitudinal direction and electrically connected to the electrode assembly; and a pair of cap assemblies each coupled to both open ends of the case and having terminal portions electrically connected to the current collection plate, wherein each of the terminal portions may include a terminal post that protrudes toward the current collection plate and is electrically connected to the current collection plate.