Battery Cell Tab Layout to Reduce Electrode Assembly Thickness
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Solution Overview
Problem
Battery cells face challenges in increasing energy density and safety performance due to the protrusion of electrode tabs, which leads to increased thickness and potential lithium precipitation from uneven local stresses.
Innovation Solution
The design of a battery cell with an electrode assembly featuring a straight and bending region, where the electrode tab protrudes from the surface in a specific direction without overlapping with the winding terminating section, utilizing space to reduce thickness and stress, and includes a protection member to cover the tab and prevent burrs, enhancing current flow and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode tab protrudes from the surface of the electrode plate in the straight region, then the current flow capability is improved, but the thickness of the electrode assembly increases
Solution Approach 1:
The electrode tab is positioned in the straight region and arranged in the first direction (winding direction) rather than protruding in the second direction (thickness direction). This dimensional reorientation allows the tab to extend along the winding axis without increasing the thickness of the electrode assembly, thereby maintaining compact form factor while ensuring adequate current flow capability through the tab's extended surface area in the plane of the electrode assembly.
Solution Approach 2:
The electrode plate is divided into different regions with distinct functions: the straight region accommodates the electrode tab for current collection, the bending region allows for volume reduction, and the winding terminating section provides electrical connection points. This localized functional differentiation optimizes each region's performance - the tab in the straight region achieves good current flow without thickness increase, while the bending region compensates by reducing overall assembly volume.
2Reliability
If the electrode tab protrudes from the surface of the electrode plate, then the current flow capability is improved, but the uniformity of local stress distribution deteriorates
Solution Approach 1:
The electrode assembly is divided into functionally distinct regions: the straight region where the tab is positioned experiences uniform stress distribution suitable for current collection, while the bending region is specifically designed to accommodate stress concentration through its curved geometry. This localized functional assignment ensures that stress uniformity is maintained in the tab region, preventing lithium precipitation while preserving current flow capability.
Solution Approach 2:
The electrode plate is segmented into multiple regions with different structural characteristics: straight sections for tab placement and stress uniformity, bending sections for volume reduction and stress absorption, and terminating sections for electrical connections. This segmentation allows each region to be optimized for its specific function, with the straight region maintaining uniform stress distribution to prevent lithium precipitation while the bending region absorbs mechanical stresses.
3Quantity of substance
If the electrode assembly volume is reduced through bending regions, then the volumetric energy density is improved, but the structural complexity increases
Solution Approach 1:
The electrode assembly is segmented into straight regions and bending regions, each performing specific functions. The bending regions are strategically positioned to reduce assembly volume without requiring complex three-dimensional folding structures. Instead, simple curved sections achieve volume reduction while maintaining manufacturing feasibility and structural integrity, balancing volumetric energy density improvement with acceptable structural complexity.
Solution Approach 2:
Instead of using complex three-dimensional folding or nested structures to reduce volume, the patent employs inverted thinking by using simple bending regions that create gradual curves in the electrode assembly. This inverted approach achieves volume reduction through straightforward geometric transformations rather than complex spatial arrangements, thereby improving volumetric energy density while minimizing structural complexity and manufacturing difficulty.
Data Source
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AI summary
This application provides a battery cell (100) and an electric device. An electrode assembly (10) of the battery cell (100) includes a first electrode plate (13) and a first tab (14). The first tab (14) is electrically connected to the first electrode plate (13). The first tab (14) is located in a straight region (11). The first tab (14) at least partially protrudes from a surface of the first electrode plate (13) in a second direction (Y). The first electrode plate (13) includes a first winding terminating section (131) located in the straight region (11) and a first bending section (132) located in a bending region (12). One end of the first winding terminating section (131) is connected to the first bending section (132), and another end of the first winding terminating section (131) is a first winding terminating end (133) of the first electrode plate (13). When viewed in the second direction (Y), the first tab (14) and the first winding terminating section (131) do not overlap. The first tab (14) can utilize the space, in the straight region (11), on a side of the first winding terminating section (131) facing away from the first bending section (132). This can alleviate the problem of increased thickness of the electrode assembly (10) in the second direction (Y) at a position corresponding to the first tab (14) caused by the first tab (14) and the problem of lithium precipitation due to uneven local stresses on the electrode plate, thereby improving the volumetric energy density and safety performance of the battery cell (100).