Pouch Cell Venting Member Using Shape Memory Alloy Activation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pouch-type lithium secondary batteries face challenges in effectively venting generated gas under desired conditions, leading to potential ignition and explosion due to internal pressure, and existing solutions either cause structural issues or side reactions with electrolytes.
Innovation Solution
A pouch-type battery cell with a venting member made of shape memory alloy on its outer surface, which deforms to penetrate the battery case at a specific temperature, creating a through-hole for gas discharge, while avoiding contact with electrolytes and minimizing size increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a venting member made of shape memory alloy is added to the pouch-type battery cell, then gas venting capability under desired conditions is improved, but device complexity increases
Solution Approach 1:
The venting member is made of shape memory alloy that automatically responds to temperature changes and opens the venting hole without external control systems. The material self-activates when the battery temperature reaches the transition point, eliminating the need for complex control mechanisms while ensuring reliable gas venting
Solution Approach 2:
The shape memory alloy changes its physical state (crystalline structure) in response to temperature parameter changes. Below the transition temperature, the alloy maintains a closed configuration; above the transition temperature, it transforms to an open configuration, enabling temperature-controlled venting through material property changes rather than mechanical control systems
2Reliability
If the venting member is placed inside the pouch-type battery cell, then gas venting is achieved, but side reactions with electrolyte occur
Solution Approach 1:
The venting member is extracted from the internal environment of the battery cell and placed on the outer surface. This separation removes the shape memory alloy from contact with the electrolyte and other reactive components inside the battery, eliminating the source of harmful side reactions while preserving the venting function through the penetrable structure
Solution Approach 2:
The venting member acts as an intermediary element positioned between the battery interior and exterior environments. It provides a controlled interface for gas discharge without requiring direct contact between the shape memory alloy and battery chemicals, thus preventing harmful interactions while maintaining venting effectiveness
3Reliability
If the sealing part is bent to accommodate the venting member, then gas venting is enabled, but dead space occurs in the width direction
Solution Approach 1:
Instead of accommodating the venting member by bending in the width direction (which creates dead space), the solution places the venting member on the outer surface and utilizes the thickness dimension of the battery cell. The venting member penetrates through the battery case from the outer surface, effectively using the Z-axis dimension to resolve the venting requirement without compromising the width direction volume
4Reliability
If the venting member penetrates the battery case, then gas discharge is achieved, but battery case integrity is compromised
Solution Approach 1:
The venting member is designed to remain in a closed, non-penetrating state during normal battery operation, preserving case integrity. Only when the temperature reaches the transition point does the shape memory alloy activate and penetrate the battery case to create the venting hole, thus maintaining structural integrity during the service life while enabling emergency gas discharge when needed
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 solution allows controlled gas discharge at a desired temperature, preventing ignition and explosion, and maintains the battery cell's size and integrity by using a venting member on the outer surface.
Implementation Method 1
a venting member disposed on an outer surface of the electrode assembly receiving part, which is an adjacent portion of a sealing part of the battery case, the venting member made of a shape memory alloy that is deformed to penetrate the battery case when a temperature of the venting member increases to a value above a transition temperature of the shape memory alloy
Data Source
AI summary
A pouch-type battery cell includes a battery case including a metal layer and polymer resin layer, and an electrode assembly disposed within the battery case, the battery case further including an electrode assembly receiving part formed in at least one of an upper case and a lower case of the battery case, and a venting member disposed on an outer surface of the electrode assembly receiving part at a location adjacent to a sealing part of the battery case, wherein the venting member is made of a shape memory alloy that is deformed to penetrate the battery case when a temperature of the venting member increases to a value above a transition temperature of the shape memory alloy. A battery module including the pouch-type battery cell, and a battery pack are also provided.