Battery Cell Pressure Relief Structure for Low-Pressure Crack Suppression
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Solution Overview
Problem
Existing pressure relief mechanisms in batteries fail to function effectively at low gas pressures, leading to premature failure and reduced safety performance due to creep deformation, even when the internal pressure is below the designed actuation threshold.
Innovation Solution
A pressure relief mechanism with a first part obliquely extending into the battery cell and a second part protruding inward, featuring a fragile portion, is designed with a reinforcing structure. This mechanism suppresses cracking at low pressures by squeezing the fragile portion and extends lifespan, while at higher pressures, it allows rapid pressure relief by stretching the fragile portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pressure relief mechanism is designed with a simple structure, then the manufacturing cost is reduced, but the mechanism fails to function effectively at low gas pressures leading to premature failure
Solution Approach 1:
The pressure relief mechanism incorporates a reinforcing structure specifically in the first part to provide localized support where needed. This allows the mechanism to maintain reliability at low pressures without reinforcing the entire structure, thus controlling manufacturing costs while ensuring proper function when gas pressure is low.
Solution Approach 2:
The pressure relief mechanism is divided into distinct parts: a first part with a reinforcing structure, a fragile portion, and a second part. This segmentation allows each component to be optimized independently - the first part provides structural support at low pressures, while the fragile portion remains ready to rupture at high pressures, resolving the contradiction between manufacturing simplicity and reliability.
2Reliability
If the first part extends obliquely toward the interior of the battery cell, then the mechanism can suppress cracking at low pressures, but the device complexity increases
Solution Approach 1:
The first part extends obliquely toward the interior of the battery cell rather than perpendicular to it. This asymmetric configuration allows the first part to effectively suppress cracking of the fragile portion at low pressures by applying force at an angle, while adding minimal structural complexity compared to a symmetric design.
3Reliability
If the pressure relief mechanism is designed to activate at a high pressure threshold, then the battery safety is improved, but the mechanism may fail to prevent explosions in severe cases where pressure rises rapidly
Solution Approach 1:
The fragile portion is pre-positioned and pre-stressed by the first part at low pressures. When high pressure occurs, the fragile portion is already in a state ready for rapid rupture, enabling the mechanism to provide both safety through threshold activation and speed through pre-positioning, preventing battery explosions in severe cases.
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 prevents premature failure and enhances safety by maintaining functionality at low pressures, extending the lifespan of the pressure relief mechanism and ensuring rapid pressure release when necessary, thereby preventing battery explosions.
Implementation Method 1
When an internal gas pressure or temperature of the battery cell is less than a first preset value, the fragile portion is squeezed and pressed by the first part and/or the second part
Implementation Method 2
the fragile portion is stretched by the first part and/or the second part, and the fragile portion is stimulated to crack, thereby implementing rapid relief of pressure
Data Source
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AI summary
Embodiments of this application provide a pressure relief mechanism, a battery cell, a battery, an electrical device, and a pressure relief mechanism manufacturing method. The pressure relief mechanism is disposed on a housing plate of a battery cell, and including: a connecting portion, located in a peripheral region of the pressure relief mechanism, and configured to connect to the housing plate; a first part, where one end of the first part is connected to the connecting portion, and the other end of the first part extends out obliquely toward an interior of the battery cell; a fragile portion, connected to the extending end of the first part; and a second part, taking a shape that protrudes toward the interior of the battery cell, where an outer edge region of the second part is connected to the fragile portion. When an internal temperature or gas pressure of the battery cell is less than a first preset value, the fragile portion is squeezed and pressed by the first part and/or the second part. The technical solutions of embodiments of this application can effectively extend the lifespan of the pressure relief mechanism.