Battery Current Collector Insulation for Smooth Bending
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing secondary batteries face issues with insulation layer detachment during bending, leading to foreign matter generation and potential battery failure or short circuits, particularly in cylindrical batteries.
Innovation Solution
The configuration of an insulating layer with a height difference on the bent side of the current collector, where the lower insulating layer on one side reduces pressure and prevents detachment, ensuring smoother bending and improved safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the uncoated region of the current collector is bent to improve winding compactness, then the energy density is improved, but the insulating layer may detach and cause foreign matter generation leading to battery failure
Solution Approach 1:
The insulating layer is designed with different heights at different locations: a first insulating layer on the bent side and a second insulating layer on the non-bent side. The first insulating layer has a lower height to accommodate bending without detachment, while the second insulating layer maintains sufficient height for insulation. This local differentiation allows the bent region to achieve compact winding for improved energy density while preventing insulating layer detachment that would cause foreign matter and battery failure.
Solution Approach 2:
The insulating layer is segmented into two distinct parts: a first insulating layer positioned on the bent side with reduced height, and a second insulating layer positioned on the non-bent side with normal height. This segmentation allows each part to perform its specific function - the first layer prevents detachment during bending while the second layer provides adequate insulation, thereby resolving the contradiction between achieving compact winding for energy density and maintaining battery safety.
2Ease of manufacture
If a uniform insulating layer is used on both sides of the current collector, then the manufacturing process is simple, but the insulating layer on the bent side detaches causing foreign matter and battery failure
Solution Approach 1:
Rather than using a uniform insulating layer throughout, the patent applies local quality by creating a first insulating layer with reduced height on the bent side where detachment occurs, and a second insulating layer with full height on the non-bent side. This localized modification addresses the specific problem of insulating layer detachment during bending while maintaining adequate insulation elsewhere, improving battery safety without significantly complicating the manufacturing process.
3Ease of operation
If the insulating layer height is reduced on the bent side, then the bending process becomes smoother and detachment is prevented, but the insulating coverage is reduced
Solution Approach 1:
The insulating layer coverage is optimized locally by reducing the height of the first insulating layer only on the bent side where bending smoothness is required to prevent detachment. The second insulating layer on the non-bent side maintains full height and adequate coverage for insulation purposes. This localized adjustment achieves the dual benefit of smooth bending operation and sufficient insulating coverage where needed.
Solution Approach 2:
The insulating layer is segmented into a first insulating layer with reduced height on the bent side and a second insulating layer with full height on the non-bent side. This segmentation allows the bent side to achieve smooth bending without detachment while the non-bent side maintains adequate insulating coverage, effectively resolving the contradiction between bending smoothness and insulating coverage.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A secondary battery (100) includes an electrode assembly (120), including a first electrode sheet (10), a second electrode sheet (20), and a separator (122). The first electrode sheet includes a first current collector (18), having opposite first surface (181) and second surface (182), partial surfaces of the first surface and the second surface is covered by a first active material layer (16), the first current collector includes an uncoated region (18a); an insulating layer (40), covering at least part of the uncoated region (18a), including a first insulating layer (40a) located at the first surface and a second insulating layer (40b) located at the second surface. The uncoated region of the first current collector bends towards the first surface, a second upper end surface (402) of the second insulating layer (40b) exceeds a first upper end surface (401) of the first insulating layer in a first direction.