Battery Cell Venting Triggered by Active Substance Release
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Solution Overview
Problem
Lithium battery cells face safety risks due to thermal runaway, where internal pressure and temperature increases can lead to deflagration if not discharged promptly, causing serious accidents, especially when the thermal runaway location is far from the pressure relief member, preventing effective actuation of the pressure relief mechanism.
Innovation Solution
Incorporating a sealing member that actuates to release an active substance, such as oxidizing agents, to increase internal pressure or temperature, triggering the pressure relief member and ensuring effective discharge of pressure or temperature, even when the thermal runaway occurs far from the pressure relief member, by creating a chemical reaction that breaks the electrode assembly and generates high-temperature, high-pressure gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure relief member is installed in the battery cell, then the battery cell can discharge internal pressure when thermal runaway occurs, but the pressure relief member may not be actuated effectively when the thermal runaway location is far from the pressure relief member
Solution Approach 1:
An active substance is introduced as an intermediary between the thermal runaway source and the pressure relief member. When thermal runaway occurs, the active substance reacts with the electrolyte to generate gas and increase internal pressure, which then actuates the pressure relief member to discharge pressure. This mediator ensures reliable pressure relief regardless of the distance between the thermal runaway location and the pressure relief member.
Solution Approach 2:
The active substance is pre-positioned within the battery cell housing, ready to react when thermal runaway occurs. This preliminary preparation ensures that the pressure-generating reaction can immediately occur to drive the pressure relief mechanism, without requiring the thermal runaway to directly reach the pressure relief member.
2Reliability
If the internal pressure and temperature are discharged quickly, then safety performance is improved, but the structural complexity increases due to additional components
Solution Approach 1:
The active substance serves multiple functions: it reacts with the electrolyte to generate gas for actuating the pressure relief member, and the reaction process itself helps to consume harmful substances during thermal runaway. This multi-functionality reduces the need for additional separate safety components.
Solution Approach 2:
The invention changes the physical and chemical parameters within the battery cell by introducing the active substance that undergoes exothermic reactions and gas generation. This parameter change enables the pressure relief mechanism to be actuated through chemical energy conversion rather than requiring complex mechanical sensing and actuation systems.
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 ensures rapid and effective discharge of internal pressure or temperature, enhancing the safety performance of the battery cell by ensuring the pressure relief member is actuated, even if the thermal runaway location is distant, thereby preventing deflagration and maintaining the battery's original energy density.
Implementation Method 1
the active substance is able to react with the electrolyte and/or the electrode assembly to increase the internal pressure or temperature of the battery cell
Implementation Method 2
the sealing member is configured to be actuated when an internal pressure or temperature of the battery cell reaches a first threshold, to release the active substance
Data Source
AI summary
A battery cell, including a housing, a pressure relief member disposed on a first wall of the housing, an electrode assembly disposed inside the housing, an electrolyte immersing the electrode assembly, and a sealing member and an active substance that are disposed inside the housing. The sealing member is configured to seal the active substance on a side of electrode assembly close to the first wall. The sealing member is configured to be actuated when an internal pressure or temperature of the battery cell reaches a first threshold, to release the active substance, and the active substance is able to react with the electrolyte and/or the electrode assembly to increase the internal pressure or temperature of the battery cell, so as to actuate the pressure relief member. The battery cell can quickly discharge its internal temperature and pressure when experiencing thermal runaway, and the battery cell has good safety performance.