Battery Pack Vent Cap for Thermal Runaway Gas Discharge
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Solution Overview
Problem
High-temperature exhaust gas ejected from lithium ion batteries can cause thermal runaway and reduce safety due to uncontrolled discharge, as existing discharge valves do not effectively manage the high-temperature gases, potentially heating adjacent battery cells.
Innovation Solution
A battery pack design featuring a heat-resistant cap with discharge gaps that guides and attenuates high-temperature exhaust gas, preventing it from reaching adjacent cells and ensuring safe discharge outside the battery case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a discharge valve is provided to ensure safety against internal pressure increase, then safety against rupture is improved, but high-temperature exhaust gas is vigorously ejected causing thermal runaway risk
Solution Approach 1:
A heat-resistant cap is introduced as an intermediary component between the discharge valve and the external environment. This cap includes a discharge hole that guides and cools the high-temperature exhaust gas, preventing direct contact with adjacent battery cells while still allowing pressure relief. The cap acts as a mediator that maintains the safety function of the discharge valve while eliminating the harmful thermal effects.
Solution Approach 2:
The discharge hole in the heat-resistant cap is positioned at a different spatial location and orientation relative to the discharge valve opening. By changing the dimensional arrangement - specifically positioning the discharge hole at the end of a cap that extends from the battery case - the exhaust gas is directed along a different path that avoids adjacent cells, thus resolving the contradiction between pressure relief and thermal safety.
2Stress or pressure
If the discharge valve opens at predetermined pressure to prevent rupture, then pressure safety is improved, but the vigorously ejected high-temperature gas may heat adjacent battery cells
Solution Approach 1:
The heat-resistant cap serves as a thermal mediator that intercepts the high-temperature exhaust gas before it can reach adjacent battery cells. The cap's discharge hole provides a controlled pathway that allows the gas to escape while the cap structure itself absorbs and dissipates some of the thermal energy, reducing the temperature of the gas by the time it exits to the environment.
Solution Approach 2:
The heat-resistant cap is pre-installed on the discharge valve, providing a protective barrier before any thermal runaway event occurs. This beforehand preparation ensures that when the discharge valve opens during an emergency, the exhaust gas is immediately channeled through the cap's discharge hole rather than directly into the surrounding environment, thus cushioning against potential thermal damage to adjacent cells.
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 energy of high-temperature exhaust gas, preventing thermal runaway and enhancing safety by controlling the flow direction and dissipating thermal energy outside the battery pack.
Implementation Method 1
The exhaust gas discharged to the valve-side end surface of the battery cell passes through a discharge gap including the first discharge gap and the second discharge gap, and is discharged from the exhaust opening to an outside
Implementation Method 2
a heat-resistant cap coupled to an end of the battery block
Data Source
AI summary
In a battery pack, a heat-resistant cap is coupled to an end of a battery block including battery cells each having a discharge valve on an end surface thereof and arranged in plural rows. A valve-side end surface of battery cell is arranged at a first end of the battery block to which heat-resistant cap is coupled. Heat-resistant cap includes closing plate providing a first discharge gap between the closing plate and end surface of the battery block, a peripheral wall coupled to a periphery of closing plate and providing a second discharge gap between the peripheral wall and an outer circumference of the battery block, a partition wall disposed between end surfaces of adjacent battery cells and partitioning the first discharge gap into portions at end surfaces of battery cells.