Battery Cell Pressure-Relief Mechanism for Thermal Runaway Venting
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Solution Overview
Problem
Battery cells face the risk of pressure-relief blasting due to thermal runaway, which can lead to safety issues and instability, as the pressure-relief mechanism may blast prematurely due to alternating fatigue aging or breakage of the weak portion, even when internal pressure does not reach the preset threshold value.
Innovation Solution
A battery cell design featuring a pressure-relief mechanism with a weak portion and a protective part, where the protective part increases the strength of connection between the first and second portions, and changes physical properties to facilitate the timely breakage of the weak portion when internal pressure reaches the threshold, ensuring safe pressure release during thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the weak portion of the pressure-relief mechanism is made thinner to ensure timely breakage during thermal runaway, then the pressure release function is improved, but the weak portion becomes susceptible to alternating fatigue aging and premature breakage during normal use
Solution Approach 1:
The pressure-relief mechanism is segmented into three distinct portions: the first portion (thicker, stronger), the weak portion (thinner, designed to break), and the second portion (thicker, stronger). This segmentation allows each part to fulfill its specific function - the weak portion breaks during thermal runaway while the first and second portions provide structural support and resist fatigue during normal operation.
Solution Approach 2:
Different portions of the pressure-relief mechanism have different local qualities in terms of thickness and strength. The weak portion has reduced thickness (e.g., 0.5-2mm) to enable breakage at threshold pressure, while the first and second portions have greater thickness (e.g., 2-5mm) to provide structural integrity and resist alternating stresses during normal battery operation.
2Stability of the object's composition
If the protective part is added to increase connection strength between first and second portions, then the resistance to alternating fatigue aging is improved, but the device complexity increases
Solution Approach 1:
The protective part acts as an intermediary element between the first portion and the second portion of the pressure-relief mechanism. It reinforces the connection between these two portions, distributing and sharing the alternating stresses that occur during normal battery operation, thereby preventing fatigue aging and premature breakage of the weak portion.
3Reliability
If the protective part changes physical properties at threshold pressure to reduce connection force, then the pressure release function is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The protective part is designed to undergo parameter changes (physical property changes) when the internal pressure reaches the threshold value. This could involve changes in viscosity, elasticity, or other mechanical properties that reduce the connection force between the protective part and the pressure-relief mechanism, allowing the weak portion to break and release pressure effectively.
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 effectively reduces the likelihood of premature pressure-relief blasting by sharing alternating stresses and ensuring the weak portion breaks only when necessary, enhancing the safety and stability of the battery cell during normal use and thermal events.
Implementation Method 1
the protective part is further configured to change in physical properties when the internal pressure of the casing reaches the threshold value so as to reduce or remove the force of connection of the protective part to the first portion or the second portion
Data Source
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AI summary
The present application relates to a battery cell, a battery, an electrical device, and a method and equipment for manufacturing battery cells. The battery cell includes a casing, a pressure-relief mechanism and a protective part. The casing has a wall portion; the pressure-relief mechanism is provided on the wall portion. The pressure-relief mechanism includes a weak portion and a first portion and a second portion which are provided on two sides of the weak portion. The weak portion is used to connect the first portion and the second portion, and the pressure-relief mechanism is configured in such a way that the weak portion is broken to release pressure when the pressure in the casing reaches a threshold value. The protective part is arranged on the pressure-relief mechanism, and the protective part is used to connect the first portion and the second portion to increase strength of connection between the first portion and the second portion. The present application provides the battery cell, the battery, the electrical device, and the method and equipment for manufacturing battery cells, aimed at solving the problem of potential pressure-relief blasting when the battery cell is in thermal runaway.