Battery Cell Case Fold Lines Prevent Collapse
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Solution Overview
Problem
Pouch-type battery cells face issues with case collapse and reduced internal space during electrolyte injection and gas discharge, leading to insufficient electrolyte filling and potential swelling of battery cell surfaces.
Innovation Solution
The battery cell design features a case with a sidewall portion and a planar portion, where the angles of inclination between the sidewalls and the planar portion are strategically different, forming fold lines to enhance hardness and prevent collapse, ensuring a maximum internal space is maintained and filled with electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pouch-type case is used for battery cell, then flexibility and sealing are improved, but case hardness and structural stability deteriorate
Solution Approach 1:
The case is constructed as a composite structure combining an Al thin film layer with insulating material layers. The Al thin film provides flexibility and sealing performance, while the insulating material layers (such as polypropylene or polyethylene) provide structural strength and hardness. This composite material approach resolves the contradiction between flexibility and structural stability.
2Productivity
If electrolyte injection and gas discharge are performed in pouch-type battery cell, then battery operation is enabled, but case collapse and internal space reduction occur
Solution Approach 1:
The case is designed with predetermined fold lines created by pressing treatment during manufacturing. These fold lines create a cushioning effect that allows the case to expand and contract during electrolyte injection and gas discharge without collapsing. The fold lines act as pre-prepared expansion zones that maintain internal space while accommodating volume changes.
3Stability of the object's composition
If case hardness is increased to prevent collapse, then structural stability is improved, but flexibility and sealing performance deteriorate
Solution Approach 1:
The case structure implements local quality differentiation through the composite material design. The Al thin film portions provide flexibility and sealing at critical sealing edges, while the insulating material portions provide structural stability in body regions. This localized functional differentiation allows both flexibility and structural stability to coexist in different parts of the same case structure.
Data Source
AI summary
A battery cell comprises a case including a sidewall portion defined as a depth of a receiving space and a planar portion extended from the sidewall portion and completing the receiving space; and an electrode assembly formed in such a manner that a plurality of electrode plates are stacked and accommodated in the receiving space of the case. In addition, the sidewall portion includes a first side wall and a second side wall protruding outwardly of the first side wall and expanding the receiving space.