Battery Cell Tab Bending Structure for Expansion-Induced Breakage
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Solution Overview
Problem
Battery cell expansion during charging and discharging affects reliability, leading to potential tab breakage and short circuits.
Innovation Solution
Incorporating a bending portion between the side edges of the tab to allow for a relaxed state, which offsets distance changes during electrode body expansion, reducing tab pulling and the risk of breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tab is made straight and rigid to ensure structural strength, then the tab can maintain good electrical connection, but the tab is more prone to breakage when the electrode body expands during charging and discharging
Solution Approach 1:
The patent applies curvature by introducing a bending portion (first curvature) in the tab structure. This bending portion allows the tab to flex and accommodate the expansion of the electrode body during charging and discharging cycles, preventing the tab from breaking while maintaining its structural integrity and electrical connection functionality.
Solution Approach 2:
The patent makes the tab structure dynamic by incorporating a bending portion that can change its curvature state. The tab transitions from a relatively straight state to a more curved state during electrode expansion, and vice versa during contraction, allowing the tab to adapt to dimensional changes and reduce mechanical stress.
2Reliability
If the tab is made flexible with a bending portion to accommodate electrode expansion, then the tab breakage risk is reduced, but the tab may experience excessive pulling and deformation
Solution Approach 1:
The patent applies partial action by introducing only a specific bending portion at a strategic location in the tab, rather than making the entire tab flexible. This localized curvature provides just enough flexibility to accommodate electrode expansion while maintaining overall tab stability and minimizing excessive pulling or deformation.
Solution Approach 2:
The patent changes the geometric parameters of the tab by introducing a controlled bending portion with specific curvature radius and angle. This parameter modification allows the tab to have optimal flexibility-strength balance, accommodating electrode expansion without causing excessive pulling or deformation during battery operation.
3Volume of stationary object
If the distance between the electrode body and connector is reduced to minimize cell size, then the energy density is improved, but the tab is more likely to abut against the connector and cause short circuit during expansion
Solution Approach 1:
The patent applies curvature to the tab structure, introducing a bending portion that prevents the tab from becoming a straight rigid element. This curved structure allows the tab to flex during electrode expansion, reducing the likelihood of the tab abutting against the connector and causing short circuit, while still allowing for compact cell design.
Solution Approach 2:
The bending portion in the tab acts as a pre-designed cushioning element that absorbs the mechanical stress during electrode expansion. This beforehand cushioning prevents the tab from directly contacting the connector during expansion, thereby preventing short circuits while maintaining compact cell dimensions.
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
Improves battery cell reliability by minimizing tab breakage and short circuits while maintaining energy density.
Implementation Method 1
a bending portion is provided between the first side edge and the second side edge of the tab... when the tab changes from the relaxed state to a tensioned state, the bending portion can provide a part of the length to offset a distance difference
Data Source
AI summary
The present application belongs to the technical field of batteries, and provides a battery cell, a battery, and an electric device. The battery cell includes an electrode body, tabs, and connectors. The tab has a first side edge and a second side edge opposite to each other, the first side edge of the tab is connected to the electrode body, and the connector is connected to the second side edge of the tab. A bending portion is provided between the first side edge and the second side edge of the tab. According to the battery cell provided in the present application, the possibility that the tab is pulled and broken when the battery cell expands can be reduced, thereby improving the reliability of the battery cell.