Cylindrical Battery Tab Structure for Vibration-Resistant Connection
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Solution Overview
Problem
Cylindrical batteries face issues with positive electrode tabs disconnecting due to external vibration, primarily because the folded portions lack sufficient physical durability and rigidity.
Innovation Solution
The cylindrical battery design incorporates a positive electrode tab with at least one folded portion and an extension portion that disperses stress by forming interconnected first and second connection portions, which are connected via a stress distribution induction portion or notches, and can be Z-shaped to enhance rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the positive electrode tab is folded using a conventional jig and folding knife, then the tab can be connected to the top cap and electrode assembly, but the folded portion lacks physical durability and rigidity, causing disconnection under external vibration
Solution Approach 1:
The positive electrode tab is divided into multiple segments: a first connection portion connected to the top cap, a second connection portion connected to the electrode assembly, and an extension portion connecting these two segments. This segmentation allows each part to perform its specific function while the extension portion provides structural support to prevent disconnection at the folded portions.
Solution Approach 2:
The extension portion protrudes from the folded portion in a direction extending along the axis of the electrode assembly, adding a dimensional element that provides mechanical reinforcement. This axial extension creates a support structure that prevents the folded portions from disconnecting under external vibration while maintaining the compact folded configuration.
2Quantity of substance
If the positive electrode tab is made thin with a thickness of 0.05 to 0.3 mm, then the battery can achieve high energy density, but the folded portion becomes weak and disconnects under stress or vibration
Solution Approach 1:
The tab structure is segmented into thin connection portions (for high energy density) and a thicker extension portion (for structural strength). The connection portions maintain thin thickness to maximize energy density, while the extension portion provides the necessary mechanical strength to prevent disconnection.
Solution Approach 2:
Different parts of the positive electrode tab have different thicknesses and properties: the first and second connection portions are thin (0.05 to 0.3 mm) to maximize energy density, while the extension portion has greater thickness to provide local structural reinforcement at the critical folded regions.
3Ease of manufacture
If the folded portion is pressed strongly by the folding knife, then the tab can be bent and connected, but the physical durability and rigidity of the folded portion become weak
Solution Approach 1:
The extension portion is formed to protrude from the folded portion before the battery undergoes any operational stress or vibration. This preliminary structural configuration ensures that when stress is applied during operation, the extension portion is already in place to provide support and prevent disconnection, maintaining stability throughout the battery's lifecycle.
Data Source
AI summary
Disclosed is a cylindrical battery in which electrode assembly is built into a battery case, wherein a top cap is mounted at the upper part of the electrode assembly, the top cap and the electrode assembly are electrically connected by a positive electrode tab, and the positive electrode tab includes an extension portion protruding from the folded portion of the positive electrode tab.