Rechargeable Battery Safety Assembly and Tab Design
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Solution Overview
Problem
Rechargeable batteries face safety issues due to potential short circuits caused by conductive foreign objects, which can lead to overheating and explosion, and manufacturing challenges related to the thin metal sheets used in electrode uncoated portions during current collecting tab attachment.
Innovation Solution
The design incorporates a safety assembly with conductive plates and auxiliary plates made of the same material as the electrodes, coupled with supporting protrusions and current collecting tabs, to safely discharge current in case of a short circuit and stabilize the attachment of thin metal sheets during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a thin metal sheet is used for the electrode uncoated portion, then the battery can be made more compact and efficient, but the thin metal sheet may be torn or stick to the current collecting tab during welding
Solution Approach 1:
The current collecting tab is divided into multiple segments or layers, with the thin metal sheet electrode uncoated portion being one layer and additional supporting layers being other layers. This segmentation allows the thin metal sheet to maintain its compactness while the combined structure provides sufficient strength to prevent tearing during welding.
Solution Approach 2:
The current collecting tab uses a composite structure combining the thin metal sheet electrode uncoated portion with additional supporting materials or layers. This composite approach maintains the compactness benefits of the thin metal sheet while adding structural integrity to prevent tearing and sticking during the welding process.
2Reliability
If a thick current collecting tab is used to prevent tearing, then the electrode uncoated portion can be better supported, but the welding process becomes more difficult and complex
Solution Approach 1:
The current collecting tab is segmented into multiple thin layers instead of using a single thick tab. This segmentation maintains adequate support for the electrode uncoated portion while keeping each individual layer thin enough to weld easily, thus simplifying the welding process.
Solution Approach 2:
Instead of changing the thickness parameter of the current collecting tab (which would make welding difficult), the solution changes the structural configuration parameter by using multiple thin layers. This maintains the support function while keeping the welding parameters favorable.
3Reliability
If safety devices are added to prevent short circuits, then battery safety is improved, but the device structure becomes more complex
Solution Approach 1:
The current collecting tab structure serves multiple functions: it collects current, supports the electrode uncoated portion, prevents short circuits through its insulating properties, and provides mechanical strength. By making the current collecting tab multi-functional, additional safety devices are not needed, thus avoiding increased device complexity.
Solution Approach 2:
The safety function is merged with the current collecting tab structure itself rather than being implemented as a separate safety device. The insulating layer or structure of the current collecting tab simultaneously performs current collection and safety functions, simplifying the overall device structure.
Data Source
AI summary
A rechargeable battery includes: a case; an electrode assembly housed in the case and including a first electrode, a second electrode, and a separator between the first electrode and the second electrode, the first electrode having a coated portion coated with a first active material and an uncoated portion absent the first active material; a safety assembly including a first electric conductive plate and a first supporting protrusion extending from the first electric conductive plate and physically coupled to the uncoated portion; a current collecting tab electrically coupling the electrode assembly with the terminal and physically coupled to the uncoated portion; and a first auxiliary plate physically coupled to the uncoated portion at a surface of the uncoated portion opposite to where the first supporting protrusion is physically coupled to the uncoated portion.