Pouch Battery Cell Structure for Impact-Induced Short-Circuit Prevention
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Solution Overview
Problem
Traditional pouch batteries with aluminum-plastic films have poor impact resistance, affecting their safety performance due to low strength and hardness.
Innovation Solution
A battery cell design featuring an electrode assembly with outer and inner electrode plates, separators, and a packaging bag with a metal layer, where the strength ratio between the first current collector and the metal layer is optimized (0.2≤S1/S2≤0.5) to ensure sequential fracture and separation upon impact, preventing short circuits and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aluminum-plastic films are used as packaging bags, then the battery structure is simple and easy to manufacture, but the strength and impact resistance are poor
Solution Approach 1:
The packaging bag uses a composite structure with metal layer (first packaging layer) and aluminum-plastic film (second packaging layer). The metal layer provides high strength and impact resistance, while the aluminum-plastic film maintains sealing performance and chemical stability. This composite material approach resolves the contradiction between strength and manufacturing simplicity.
Solution Approach 2:
The packaging bag is segmented into multiple functional layers: the metal layer for mechanical strength and impact resistance, and the aluminum-plastic film layer for sealing and chemical protection. This segmentation allows each layer to specialize in its function, achieving high impact resistance while maintaining ease of manufacture through standardized layering processes.
2Reliability
If the first current collector strength S1 is increased to protect inner electrode plates, then structural protection is improved, but the risk of incomplete fracture and short circuit increases under impact
Solution Approach 1:
The patent optimizes the strength parameter S1 of the first current collector to a specific range (0.2≤S1/S2≤0.5 relative to the metal layer strength S2). This parameter optimization ensures the current collector is strong enough to protect inner electrode plates during normal operation, but weak enough to fracture completely under impact, preventing short circuits. The aluminum-plastic film layer provides additional protection while maintaining this balance.
3Strength
If the packaging bag uses only metal layer, then impact resistance is improved, but sealing performance and chemical stability deteriorate
Solution Approach 1:
The packaging bag combines metal layer and aluminum-plastic film layer, where the metal layer provides impact resistance and the aluminum-plastic film provides sealing performance and chemical stability. This composite structure resolves the contradiction between impact resistance and sealing performance by assigning different functions to different materials.
Data Source
AI summary
A battery cell includes an electrode assembly and a packaging bag. The electrode assembly includes first electrode plates, second electrode plates and separators. The first electrode plates include two outer electrode plates and at least one inner electrode plate. In the first direction, the two outer electrode plates are disposed on two outermost sides of the electrode assembly respectively, the inner electrode plate is disposed between the two outer electrode plates, and the second electrode plates are disposed between the two outer electrode plates. The packaging bag includes a metal layer, and a relationship between a first strength S1 of the first current collectors in the outer electrode plates and a second strength S2 of the metal layer satisfies: 0.2 ≤S1/S2≤0.5.