Battery Cap Plate Sealing Structure for Swelling and Weld Heat
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Solution Overview
Problem
Existing secondary batteries face challenges in maintaining effective sealing between the cap plate and the case, particularly during swelling, and are prone to damage to the insulating coating layer due to welding heat.
Innovation Solution
The secondary battery incorporates a cap plate with a bonding area that includes support surfaces and chambers spaced apart from the case, which are designed to accommodate welding by-products and limit heat transfer to the insulating coating layer, while maintaining a sealed state even under deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding is performed to bond the cap plate to the case, then the sealing performance is improved, but the insulating coating layer on the case is damaged due to welding heat
Solution Approach 1:
The bonding area acts as an intermediary structure between the cap plate and the case. It includes a first extension rib that contacts the case and a second extension rib that contacts the cap plate, with a chamber formed between them. This intermediary structure allows welding to occur at the bonding area while the chamber accommodates welding by-products and the support surface limits heat transfer to the insulating coating layer on the case, thus protecting it from damage.
2Strength
If the cap plate is welded directly to the case, then the bonding strength is improved, but welding by-products can flow into the case causing contamination
Solution Approach 1:
The chamber in the bonding area converts the harmful welding by-products into a contained element. The chamber is specifically designed to accommodate welding by-products generated during the welding process, preventing them from flowing into the case and contaminating the battery components. The support surface limits heat transfer while the chamber captures the by-products, transforming a potential harm into a controlled feature.
3Reliability
If the bonding area is in direct contact with the case, then the sealing is improved, but the structure cannot maintain sealing during swelling
Solution Approach 1:
The bonding area is segmented into multiple functional zones: a first extension rib that contacts the case, a second extension rib that contacts the cap plate, and a chamber formed between them. The support surface is spaced apart from the case by a specific distance, creating a non-contact zone. This segmentation allows the structure to maintain sealing through the distributed contact points while accommodating swelling deformation through the chamber and spaced support surface.
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
This design effectively prevents damage to the insulating coating layer and maintains a sealed structure by accommodating welding by-products and limiting heat transfer, ensuring the battery's integrity during swelling and deformation.
Implementation Method 1
a weld bead spaced apart from an inner surface of the case by a support surface and limiting contact between the weld bead and an insulating coating layer formed on the inner surface of the case, wherein the weld bead is bonded to the case
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A secondary battery is disclosed. The secondary battery includes an electrode assembly, a case including an opening for insertion of the electrode assembly, and a cap plate including a bonding area welded to the case and closing the opening. The bonding area may include one or more support surfaces in contact with and supported by the case; and one or more chambers formed with a portion of the bonding area spaced apart from the case by the support surface.