Battery Pack Case Sealing Structure for Expansion Pressure
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Solution Overview
Problem
Existing battery packs lack sufficient strength against expansion pressure from thermal runaway of battery cells, which can lead to disassembly of the case.
Innovation Solution
A battery pack design featuring a case with a sealing portion that resists shearing forces rather than detachment forces, using a sealing structure that maintains integrity even under increased internal pressure, allowing for improved strength and reduced material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sealing structure is used at the joining surface between case body and cover plate, then waterproofness is improved, but strength against expansion pressure deteriorates
Solution Approach 1:
The sealing function is segmented from the joining surface itself and placed in a dedicated sealing groove. The sealing member is positioned in a groove that is recessed from the joining surface, separating the sealing function from the structural joining function. This allows the joining surface to maintain full contact for strength while the sealing member handles waterproofing.
Solution Approach 2:
The sealing member is nested within a sealing groove that is formed in the case body or cover plate. The sealing groove is recessed from the joining surface, creating a nested structure where the sealing member sits inside the groove rather than protruding from the joining surface. This nested configuration protects the sealing member and maintains joining strength.
2Ease of manufacture
If the case is designed to be disassembled afterward, then ease of assembly is improved, but structural strength deteriorates
Solution Approach 1:
The sealing function is segmented from the joining surface and assigned to a dedicated sealing groove and sealing member. This segmentation allows the joining surface to be optimized for structural strength while the sealing components handle the sealing function. The joining surface can maintain full contact for strength without being compromised by sealing structures.
Solution Approach 2:
The sealing groove acts as an intermediary structure that mediates between the joining surface and the sealing member. It provides a dedicated space for the sealing member while maintaining the integrity of the joining surface. The groove is formed by protrusions or recesses that create this intermediary sealing zone without compromising the joining strength.
Data Source
AI summary
A battery pack includes: a plurality of battery cells arranged side by side along a first direction; and a case having an inner space for accommodating the plurality of battery cells. The case includes a first member, a second member that forms the inner space together with the first member, and a sealing portion that seals a joining portion between the first member and the second member. The first member has a first portion in abutment with the sealing portion. The second member has a second portion facing the first portion with the sealing portion being interposed between the second portion and the first portion. When an expansion pressure of the inner space acts on the case, a force in a shearing direction acts on the sealing portion sandwiched between the first portion and the second portion.