Assemble-Type Secondary Battery Cap Assembly
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Solution Overview
Problem
Current battery pack structures face challenges such as high production costs, complex assembly processes, and difficulties in miniaturization due to the need for separate cases and ultrasonic welding, leading to increased rejection rates and costs.
Innovation Solution
A secondary battery design featuring a cap assembly that is detachably coupled to the cell body, eliminating the need for welding and separate cases, and utilizing electrode leads for electrical connections, which simplifies the assembly process and reduces production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic welding is used to couple top and bottom cases, then the battery pack structure is secured, but the battery size must be larger than a predetermined thickness and minute flow occurs during welding leading to high rejection rate
Solution Approach 1:
The patent extracts and eliminates the ultrasonic welding process from the battery assembly. Instead of welding the cap assembly to the cell body, the invention uses a mechanical coupling structure where the cap assembly is directly coupled to the cell body through integrated positioning features, removing the need for thermal processing and associated thickness requirements.
Solution Approach 2:
The patent replaces the ultrasonic welding mechanical system with a direct mechanical coupling system. The cap assembly includes positioning protrusions that fit into corresponding recesses on the cell body, creating a secure mechanical connection without thermal energy input, thereby eliminating the minimum thickness constraint imposed by welding requirements.
2Reliability
If separate top and bottom cases are used to enclose the cell body, then the battery structure is complete and stable, but the assembly process becomes complex and production costs increase
Solution Approach 1:
The patent merges the protective case function into the cap assembly itself. The cap assembly is designed to provide both the electrical connection function and the structural enclosure function, eliminating the need for separate top and bottom cases. This integration simplifies the overall structure while maintaining structural stability through the unified design.
Solution Approach 2:
The cap assembly is designed with multi-functionality, serving both as the electrical connection interface and as the structural protective case. By combining multiple functions into a single component, the patent reduces the number of parts and assembly steps while ensuring structural completeness and stability.
3Adaptability or versatility
If multiple components (PTC element, nickel plate, protection circuit, top and bottom cases) are assembled separately, then each component can be optimized independently, but the assembly process requires many steps resulting in high rejection rate and production costs
Solution Approach 1:
The patent combines the PTC element, nickel plate, and protection circuit into an integrated cap assembly unit. These components are pre-assembled and configured within the cap assembly before being coupled to the cell body, reducing the number of discrete assembly steps. This merging maintains the ability to optimize each component independently while significantly improving assembly efficiency by reducing the total number of assembly operations.
Data Source
AI summary
Provided is a secondary battery of an assemble-type structure having a cell body including an electrode assembly of cathode/separator/anode sealed therein; and a cap assembly including a protection circuit electrically connected to the cell body so as to control overcharge, overdischarge and overcurrent of the battery and a cap housing covering an upper part of the battery, and being detachably coupled to the cell body. Since the cap assembly including the protection circuit and cap housing is assembled detachably from the cell body and electrically connected to and also can be physically firmly fixed to one another, provided are effects capable of greatly reducing the manufacturing process steps of the battery, and solving all the problems associated with use of battery cases and insert injection molding.