Battery Electrode Insulating Layer Layout for Bend Reliability
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Solution Overview
Problem
Existing secondary batteries face issues with insulation layer detachment during bending, leading to potential battery failure and safety hazards due to foreign matter introduction.
Innovation Solution
Configuring an insulating layer on the bent side of the current collector with a height difference lower than the other side to reduce pressure and prevent detachment, ensuring smoother bending and pressing down of uncoated regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the insulating layer is configured with uniform height on both sides of the current collector, then the manufacturing process is simple, but the insulating layer detaches during bending due to excessive pressure on the bent side
Solution Approach 1:
The insulating layer is configured with asymmetric height distribution: the first insulating layer on the bent side has a first height, while the second insulating layer on the non-bent side has a second height greater than the first height. This asymmetric configuration reduces pressure concentration on the bent side during electrode assembly bending, preventing insulating layer detachment while maintaining manufacturing feasibility.
Solution Approach 2:
The insulating layer thickness is locally optimized based on functional requirements: the first insulating layer on the bent side is thinner to accommodate bending deformation, while the second insulating layer on the non-bent side is thicker to provide sufficient insulation. This local quality differentiation ensures both bending performance and insulation effectiveness.
2Ease of operation
If the insulating layer on the bent side is made thinner, then bending becomes smoother and detachment is prevented, but the insulation performance may be compromised
Solution Approach 1:
The asymmetric height configuration ensures that the thinner first insulating layer is positioned only on the bent side where flexibility is needed, while the thicker second insulating layer provides sufficient insulation on the non-bent side. This spatial differentiation resolves the conflict between bending smoothness and insulation performance.
3Reliability
If the insulating layer is made thicker to prevent detachment, then attachment reliability improves, but bending becomes more difficult and may cause defects
Solution Approach 1:
The insulating layer thickness is locally optimized: thinner on the bent side to facilitate bending, and thicker on the non-bent side to ensure attachment reliability. This local differentiation eliminates the need for uniformly thick insulating layers, simplifying the bending process while maintaining reliability.
Data Source
AI summary
A secondary battery includes an electrode assembly, including a first electrode sheet, a second electrode sheet, and a separator. The first electrode sheet includes a first current collector, having opposite first surface and second surface, partial surfaces of the first surface and the second surface is covered by a first active material layer, the first current collector includes an uncoated region; an insulating layer, covering at least part of the uncoated region, including a first insulating layer located at the first surface and a second insulating layer located at the second surface; wherein, the uncoated region of the first current collector bends towards the first surface, a direction where the first active material layer towards the insulating layer is a first direction, in the first direction, a second upper end surface of the second insulating layer exceeds a first upper end surface of the first insulating layer.