Battery Cell Reinforcement for Welded Seam Swelling Resistance
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Solution Overview
Problem
Conventional square casing cells face issues with weakened or torn welded seams due to outward expansion of the aluminum casing caused by gas production and electrode sheet expansion during charging and discharging, affecting cell safety and strength.
Innovation Solution
A cell design incorporating an outer casing, cover plate, and reinforcing members, such as L-shaped, C-shaped, T-shaped, or annular reinforcing members, connected via laser welding or gluing, to limit the relative displacement between the casing and cover, ensuring the welded seam does not fail during cyclic swelling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the aluminum casing is used as a current collector container without additional reinforcing structures, then the device complexity is reduced and manufacturing is simpler, but the welded seam strength deteriorates and the casing cover welded seam gets torn due to fatigue expansion force during charging and discharging
Solution Approach 1:
The reinforcing member is divided into a first portion that contacts the outer casing and a second portion that contacts the cover plate, creating a segmented structural solution that targets specific weakness points in the welded seam without reinforcing the entire casing structure
Solution Approach 2:
The reinforcing member is positioned specifically at the location where the welded seam is most vulnerable to fatigue expansion force, providing localized reinforcement only where needed rather than strengthening the entire casing uniformly
2Reliability
If the aluminum casing is allowed to expand freely during charging and discharging, then the ease of manufacture is improved and the casing design is simpler, but the welded seam reliability deteriorates due to cyclic swelling and fatigue expansion force
Solution Approach 1:
The reinforcing member is pre-installed on the outer casing before the cover plate is welded to it, creating a protective structure in advance that prevents the welded seam from failing during subsequent cyclic swelling operations
Solution Approach 2:
The reinforcing member acts as an intermediary element between the outer casing and the cover plate, absorbing and distributing the fatigue expansion force to protect the welded seam from direct stress
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The reinforcing members enhance the strength of the welded seam, prevent cyclic cracking, and ensure effective insulation, thereby improving the safety and reliability of the battery module and pack.
Implementation Method 1
laser welding is then performed to complete the assembly of the casing and the cover
Data Source
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AI summary
A cell (10) and a battery module (100) are provided. The cell (10) includes an outer casing (11), a cover plate (12), and a reinforcing member (13). The cover plate (12) is welded to a top portion of the outer casing (11). The reinforcing member (13) at least includes a first surface (131) and a second surface (132). The first surface (131) is fixedly connected to one of the cover plate (12) and the outer casing (11), and the second surface (132) faces the other one of the cover plate (12) and the outer casing (11).