Battery Cap Assembly With CID Venting for Activation Gas Release
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Solution Overview
Problem
Secondary batteries face limitations in performance due to gases generated during activation processes being trapped inside the can, which cannot be effectively discharged, hindering further improvements.
Innovation Solution
A cap assembly design featuring a top cap, safety vent, and current interrupt device (CID) filter with vertically aligned holes, allowing the positive electrode tab to control gas discharge through the CID hole, vent hole, and top hole, while ensuring secure closure and prevention of electrolyte leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the can is sealed to ensure safety and prevent electrolyte leakage, then reliability is improved, but gas discharge capability deteriorates
Solution Approach 1:
The cap assembly is segmented into multiple functional components: top cap with top hole, safety vent with vent hole, and CID filter with CID hole. Each segment handles specific functions - the top hole allows tool access and gas discharge, the vent hole provides gas discharge path, and the CID hole with filter controls gas discharge while preventing foreign substance ingress. This segmentation resolves the contradiction by providing dedicated pathways for gas discharge while maintaining overall sealing for safety.
Solution Approach 2:
The CID filter acts as an intermediary component between the sealed can interior and the external environment. It selectively allows gas to pass through the CID hole while blocking foreign substances. The filter mediates between the need for gas discharge and the need to prevent contamination, enabling gas escape while maintaining safety and purity.
2Object-generated harmful factors
If the CID hole is opened to discharge gas, then gas discharge capability is improved, but risk of foreign substance ingress increases
Solution Approach 1:
The CID filter provides local quality differentiation within the cap assembly. The filter material has specific properties that allow gas molecules to pass through while blocking larger foreign substance particles. This local quality enhancement at the CID hole location enables selective permeability - gas discharge is permitted while foreign substance ingress is prevented, resolving the contradiction between these two harmful factors.
Solution Approach 2:
The CID filter is made of porous material with controlled pore sizes. The porous structure allows gas molecules to pass through the CID hole while the pore dimensions are sufficiently small to block foreign substances. This application of porous materials enables the CID hole to function as a selective barrier that discharges gas while preventing contamination.
3Productivity
If multiple holes are formed in the cap assembly for gas discharge, then gas discharge efficiency is improved, but structural complexity increases
Solution Approach 1:
The cap assembly is designed with multi-functionality where each hole serves multiple purposes. The top hole functions for both tool access during assembly and gas discharge during activation. The vent hole and CID hole both contribute to gas discharge while the CID filter simultaneously prevents foreign substance ingress. This multi-functionality increases gas discharge efficiency without proportionally increasing structural complexity.
Solution Approach 2:
Multiple functional requirements are merged into a single integrated cap assembly structure. The top cap, safety vent, and CID filter are combined into one assembly that provides tool access, gas discharge pathways, and foreign substance filtration simultaneously. This merging approach achieves efficient gas discharge through multiple holes while avoiding the complexity of separate components for each function.
Data Source
AI summary
The present invention relates to a secondary battery. The secondary battery comprises: an electrode assembly; a can configured to accommodate the electrode assembly; an electrolyte impregnated into the electrode assembly while being injected into the can; and a cap assembly mounted on an opening of the can, wherein the cap assembly comprises: a top cap in which a top hole is formed to pass vertically; a safety vent which is provided under the top cap and in which a vent hole is formed to pass vertically; and a current interrupt device (CID) filter which is provided under the safety vent, to which a positive electrode tab provided in the electrode assembly is coupled, and in which a CID hole is formed to pass vertically, wherein the CID hole is closed or opened by the positive electrode tab.