Secondary Battery Current Collector Venting Under Thermal Runaway
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Solution Overview
Problem
Current secondary batteries face safety issues during thermal runaway due to the current collector blocking the discharge of internal substances despite the explosion-proof valve opening, reducing safety performance.
Innovation Solution
The secondary battery design includes a current collector with multiple fragile parts that break when internal pressure exceeds a threshold, allowing the collector to bend away from the electrode assembly and reduce obstruction to the pressure release region, enhancing structural strength and welding reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the current collector is made structurally strong to maintain electrical connection, then welding reliability is improved, but obstruction to pressure release region increases during thermal runaway
Solution Approach 1:
The current collector is divided into multiple segments along its radial direction, creating gaps between adjacent segments. These gaps allow internal substances to pass through during thermal runaway while the segmented structure maintains electrical conductivity through contact points. The segmentation resolves the contradiction by reducing obstruction to pressure release while preserving welding reliability at the contact points.
Solution Approach 2:
The current collector is designed with flexible connections between segments that allow it to deform dynamically during thermal runaway. When excessive pressure occurs, the segments can move relative to each other to clear the pressure release path, while maintaining electrical connection through resilient contact points. This dynamic behavior resolves the contradiction between structural strength and pressure release capability.
2Stability of the object's composition
If the current collector is made rigid to ensure structural stability, then manufacturing precision is improved, but discharge of internal substances is blocked during thermal runaway
Solution Approach 1:
By segmenting the current collector structure, the patent achieves both structural stability and safety performance. The segments are arranged to maintain overall structural integrity during normal operation while creating channels for substance discharge during thermal runaway. The segmented design with controlled gaps resolves the contradiction between rigidity and discharge capability.
Solution Approach 2:
The current collector incorporates a porous or perforated structure with controlled void spaces between segments. This porous design allows internal substances to pass through during thermal runaway while maintaining structural stability during normal operation. The porous structure resolves the contradiction by providing discharge pathways without compromising overall structural integrity.
3Reliability
If the current collector spans large radial distance to ensure electrical connection, then electrical conductivity is improved, but obstruction to pressure release region increases
Solution Approach 1:
The current collector is segmented radially into multiple sections with gaps between them. These segments maintain electrical conductivity through contact points while the gaps between segments create pathways for pressure release. The segmentation principle resolves the contradiction by allowing electrical connection through discrete contact points while reducing overall obstruction through the gaps.
Solution Approach 2:
The patent introduces a circumferential dimension to the current collector design by arranging segments around the radial axis. This dimensional change allows electrical connection to be maintained through circumferential contact points while radial gaps provide pressure release pathways. The multi-dimensional arrangement resolves the contradiction between electrical connection and pressure release.
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 facilitates the discharge of internal substances during thermal runaway, improving safety performance by reducing obstruction and ensuring reliable pressure release.
Implementation Method 1
when an internal pressure of the secondary battery exceeds a threshold value, the fragile part breaks
Implementation Method 2
at least a part of the current collector is bent in a direction away from the electrode assembly
Data Source
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AI summary
A secondary battery (100), a battery pack (10), and an electronic device (1) are provided. The secondary battery (100) includes a housing (110), an electrode assembly (120) accommodated in the housing (110), and a current collector (140, 150). The housing (110) includes an end wall (111, 114), and an explosion-proof valve (115) is disposed on the end wall (111, 114). The includes a tab facing the end wall (111, 114). The current collector (140, 150) is disposed between the electrode assembly (120) and the end wall (111, 114), and is electrically connected to the tab. At least one fragile part (141) is disposed on the current collector (140, 150), and the fragile part (141) is configured to break when the internal pressure of the secondary battery (100) exceeds a threshold value. At least part of the current collector (140, 150) is bent away from the electrode assembly (120).