Secondary Battery Current Interrupt Mechanism
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Solution Overview
Problem
Secondary batteries used in large applications such as electric vehicles and stationary storage systems require a reliable current interrupt mechanism to prevent damage from increased internal pressure, but existing mechanisms are prone to failure due to misalignment and deformation of insulating members under load.
Innovation Solution
A prismatic secondary battery design incorporates a pressure-sensitive current interrupt mechanism with a deformable plate and insulating members featuring rotation preventing protrusions to secure the current collector, reducing the risk of misalignment and enhancing reliability by distributing load effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure-sensitive current interrupt mechanism is implemented, then battery safety is improved, but the mechanism is prone to failure due to misalignment and deformation of insulating members under load
Solution Approach 1:
The protrusion is provided on the insulating member before assembly to prevent rotation of the current collector in advance. This preliminary structural feature ensures that when the battery undergoes impact or vibration, the current collector cannot rotate relative to the insulating member, thereby preventing misalignment and deformation of the insulating member and ensuring reliable operation of the current interrupt mechanism
Solution Approach 2:
The protrusion acts as an intermediary element between the insulating member and the current collector. It provides a mechanical constraint that mediates the interaction between these components, preventing relative rotation and ensuring stable alignment without requiring additional fastening mechanisms
2Reliability
If the first insulating member is connected to the base portion of the current collector, then the conductive path is secured, but the insulating member may be deformed when force is applied because it is made of resin
Solution Approach 1:
The insulating member has different local properties: the main body is made of resin for insulation, while the protrusion is designed with rotational constraint functionality. The protrusion provides localized mechanical support and rotation prevention at the critical interface with the current collector, while the main body maintains its insulating properties
Solution Approach 2:
The rotational constraint is built into the insulating member's structure before assembly through the protrusion. This preliminary design feature ensures that when forces are applied during battery operation, the current collector cannot rotate relative to the insulating member, preventing deformation of the resin body
3Reliability
If the current collector is connected to the deformable plate, then electrical connection is established, but the fragile portion is damaged due to load applied during impact or vibration
Solution Approach 1:
The protrusion on the insulating member provides preliminary rotation prevention that protects the fragile portion of the current collector before impact or vibration occurs. By constraining the current collector's movement in advance, the design prevents excessive loads from being applied to the fragile connection points between the current collector and deformable plate
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
The mechanism effectively disconnects the conductive path when internal pressure exceeds a threshold, preventing damage and ensuring reliable operation even under impact or vibration, thereby enhancing the safety and reliability of the battery.
Implementation Method 1
When a pressure inside the battery is higher than or equal to a predetermined value, the deformable plate is deformed and a fragile portion is broken due to deformation of the deformable plate so that a conductive path between the positive electrode sheet or the negative electrode sheet and the terminal is disconnected
Data Source
AI summary
A positive electrode sheet is electrically connected to a positive terminal with a positive electrode current collector, a deformable plate, and a conductive member interposed therebetween. When the pressure inside a battery is higher than or equal to a predetermined value, the deformable plate is deformed toward a sealing plate and an annular groove formed on a base portion of the positive electrode current collector is broken due to deformation of the deformable plate so that a conductive path between the positive electrode sheet and the positive terminal is disconnected. A first insulating member disposed between the deformable plate and the base portion of the positive electrode current collector includes a first rotation preventing protrusion on a surface thereof on a wound electrode body side and outside an outer circumferential edge of the base portion of the positive electrode current collector.