Secondary Battery Safety Member Integrating Gas Exhaustion and Current Cut-Off
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Solution Overview
Problem
Secondary batteries face challenges in simplifying the cap assembly structure to accommodate both gas exhaustion and current cut-off functions, leading to increased volume and reduced capacity.
Innovation Solution
A safety member with a specific structure, comprising an outer member, inner member, and connection member, integrated with insulation and a positive temperature coefficient, is used to perform gas exhaustion and current cut-off functions, reducing the cap assembly's volume by thinning the connection member and using thermoplastic insulation, such as PBT resin, and forming inclined sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate components are used for gas exhaustion and current cut-off functions, then reliability is improved, but device complexity increases and volume increases
Solution Approach 1:
The patent combines the gas exhaustion function and current cut-off function into a single integrated safety member. The safety member includes an outer member with a gas exhaustion hole and an inner member with a current cut-off hole, both formed in one integrated component rather than using separate parts. This merging reduces the number of components, simplifies the cap assembly structure, and maintains the reliability of both safety functions.
Solution Approach 2:
The safety member is designed to perform multiple functions simultaneously: it provides gas exhaustion through the outer member's hole, current cut-off through the inner member's hole, and structural support for the cap assembly. This multi-functional design eliminates the need for separate components for each function, reducing overall device complexity while maintaining comprehensive safety coverage.
2Reliability
If separate components are used for gas exhaustion and current cut-off functions, then reliability is improved, but volume increases and battery capacity decreases
Solution Approach 1:
By merging the gas exhaustion component and current cut-off component into a single integrated safety member, the overall volume required for these safety functions is reduced. The compact integrated design eliminates gaps and redundant structures that would exist with separate components, thereby reducing cap assembly volume and increasing available battery capacity.
3Volume of moving object
If the connection member is made thinner to reduce volume, then battery capacity increases, but manufacturing precision requirements increase
Solution Approach 1:
The connection member is designed with non-uniform thickness: thinner in regions where volume reduction is critical and stronger in regions where structural integrity is paramount. This localized quality variation optimizes the balance between reducing cap assembly volume and maintaining manufacturability, allowing thin sections to reduce overall volume while thick sections ensure adequate strength and ease of manufacturing.
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 solution allows for a more compact cap assembly, increasing the secondary battery's capacity by effectively managing internal pressure and preventing electrical shorts while enabling efficient gas release and current interruption.
Implementation Method 1
A positive temperature coefficient may be further provided between the cap-up and the safety member
Data Source
AI summary
A secondary battery includes an electrode assembly, a case and a safety member. The electrode assembly has a first electrode plate, a second electrode plate and a separator interposed between the first and second electrode plates. The case accommodates the electrode assembly, and has an opened top. The safety member is inserted into an upper inside portion of the case, and seals the case. In the secondary battery, the safety member comprises an outer member contacting an inner surface of the case and having a center passing therethrough, an inner member spaced apart from the outer member at a predetermined interval and positioned at the center of the outer member, and a connection member connecting the outer and inner members. Accordingly, it is possible to increase the capacity of the battery.