Battery Cell End Cover Venting With Nested Pressure Relief
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Solution Overview
Problem
Existing battery cell designs face challenges in ensuring safety due to insufficient pressure relief mechanisms, which can lead to explosions and fires when internal pressure exceeds threshold values, as the size of these mechanisms is limited by welding grooves and welded parts, restricting their enlargement and thus their effectiveness.
Innovation Solution
The design incorporates a concave on the end cover to accommodate a pressure relief mechanism, allowing it to cover welded parts along the thickness direction, enabling larger sizes and improved pressure relief capacity, while avoiding overlap with secondary welded parts to maintain firmness and prevent damage during welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure relief mechanism is enlarged to improve pressure relief capacity, then the safety of the battery cell is improved, but the space outside the battery cell occupied by the pressure relief mechanism increases
Solution Approach 1:
The pressure relief mechanism is nested within the concave structure of the end cover, allowing the mechanism to be housed inside the battery cell assembly rather than occupying external space. This nesting approach enables the pressure relief mechanism to be integrated into the existing structure, resolving the contradiction between improving safety through enlargement and minimizing external space occupation.
Solution Approach 2:
The pressure relief mechanism and welded parts are distributed in the thickness direction of the end cover rather than being constrained in the radial direction. This dimensional shift allows the pressure relief mechanism to be enlarged without increasing the external footprint of the battery cell, as the expansion occurs along the thickness dimension where space is more readily available.
2Reliability
If the pressure relief mechanism covers the first welded part to improve pressure relief capacity, then the safety is improved, but the welding process becomes more complex
Solution Approach 1:
The design distributes the pressure relief mechanism and first welded part in the thickness direction of the end cover, allowing them to overlap in this dimension without interfering with each other. This dimensional arrangement enables the pressure relief mechanism to cover the welded part for improved safety while maintaining a simple welding process, as the overlap occurs in the thickness direction where welding operations are not compromised.
3Reliability
If the concave and pressure relief mechanism are enlarged to improve pressure relief capacity, then the safety is improved, but the overall volume of the battery cell increases
Solution Approach 1:
The pressure relief mechanism is nested within the concave structure of the end cover, which itself is part of the battery cell assembly. This nesting allows the mechanism to be enlarged for improved safety while the concave structure efficiently utilizes the available thickness dimension, minimizing the impact on the overall external volume of the battery cell.
Solution Approach 2:
The enlargement of the pressure relief mechanism occurs primarily in the thickness direction of the end cover rather than in the radial or axial directions. This dimensional strategy allows the mechanism to be scaled up for improved pressure relief capacity while maintaining a compact external footprint, thus improving safety without significantly increasing the overall battery cell volume.
Data Source
AI summary
A battery cell may include a housing, an electrode assembly, a current collector and a pressure relief structure. The end cover may be configured for covering the opening of the housing. The current collector may be configured for connecting the electrode assembly and the end cover. The pressure relief structure may be arranged on the end cover. A side of the end cover facing away from the electrode assembly may be provided with a concave, the concave may be configured for accommodating at least a portion of the pressure relief structure, a connecting part may be formed on the end cover in an area where the concave may be provided, the connecting part may be configured for being welded to the current collector to form a first welded part, and the pressure relief structure may cover the first welded part along a thickness direction of the end cover.