Pouch Cell Venting With Controlled Seal Failure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion electrochemical cells with flexible laminate casings, commonly used in electric vehicles, lack effective pressure relief mechanisms, making them susceptible to thermal runaway, explosions, and damage due to the absence of integrated vent features.
Innovation Solution
The implementation of a pouch design with a first and second sealing region, where the second region is configured to fail at a lower pressure, and a piercing element or frame to control venting, allowing for controlled release of pressure and localization of failures, thereby preventing thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid casings with vent mechanisms are used, then pressure relief is effective, but the cell design is limited to cylindrical or prismatic shapes only
Solution Approach 1:
The patent applies flexible laminate casing with integrated sealing regions that can fail at controlled pressures. The pouch cell structure uses flexible films instead of rigid casings, allowing the cell to maintain pressure relief functionality while accommodating flexible, lightweight form factors suitable for electric vehicle applications.
2Ease of manufacture
If flexible laminate casings are used, then cell weight is reduced and manufacturing is simplified, but pressure relief mechanisms are ineffective or absent
Solution Approach 1:
The sealing region is divided into a first portion and a second portion with different failure pressures. The second portion is configured to fail at a lower pressure than the first portion, creating a segmented pressure relief system that provides controlled venting while maintaining the simplicity of flexible laminate construction.
3Ease of manufacture
If uniform sealing strength is used throughout the pouch, then manufacturing is simpler, but controlled venting cannot be achieved
Solution Approach 1:
The sealing region has non-uniform properties with a first portion and a second portion that have different failure characteristics. The second portion is specifically designed to fail at a lower pressure, creating localized weakness that enables controlled venting while the rest of the sealing maintains integrity. This local differentiation is achieved through variations in sealing pressure, temperature, or duration in specific regions.
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 enables controlled venting in lithium-ion pouch cells, reducing the risk of explosions and damage by allowing for the safe release of pressure and localization of gas venting, enhancing safety and reliability.
Implementation Method 1
the second portion configured to fail at a lower internal pressure than the first portion
Implementation Method 2
a frame including a puncture member configured to pierce the pouch in response to the pouch expanding to a larger than a threshold size
Data Source
AI summary
Embodiments described herein relate to electrochemical devices and electrochemical cells with vents and venting mechanisms. In some aspects, an electrochemical device can include an anode disposed on an anode current collector, a cathode disposed on a cathode current collector, a separator disposed between the anode and the cathode, a first film disposed on the anode current collector and having outer edges extending beyond outer edges of the anode current collector, and a second film disposed on the cathode current collector and having outer edges extending beyond outer edges of the cathode current collector, the second film bonded to the first film along a sealing region to form a pouch, the pouch having an internal pressure, the sealing region including a first portion and a second portion, the second portion configured to fail at a lower internal pressure than the first portion.