Battery Pack Venting Valve for Pressure Relief and Reaction Suppression
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Solution Overview
Problem
Thermal management systems in battery packs, such as those in electric vehicles, often fail to effectively suppress exothermic reactions caused by shorts or faults within battery cells, leading to high pressure and temperature events that result in degradation of the battery and its enclosure, as they lack a mechanism to rapidly dispense a suppressing agent to mitigate these events.
Innovation Solution
A dual-staged venting valve system coupled with a solenoid that opens to relieve pressure and temperature during exothermic reactions and then seals to retain a suppressing agent within the battery pack, slowing further thermal events by maintaining the agent inside the enclosure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cooling system or venting strategy is used to manage battery temperature, then temperature control is improved, but the ability to suppress exothermic reactions and remove oxidants is insufficient
Solution Approach 1:
The system divides the thermal management function into two separate subsystems: a cooling system for temperature control and a reaction suppression system for exothermic reaction mitigation. The reaction suppression system includes a suppressing agent reservoir and dispensing mechanism that operates independently from the cooling system, allowing each subsystem to optimize its specific function without compromise.
Solution Approach 2:
A suppressing agent (such as an inert gas or chemical agent) is introduced as an intermediary substance between the battery cells and the external environment. This agent acts as a mediator that suppresses exothermic reactions by displacing oxygen and inhibiting combustion chains, thereby filling the functional gap left by conventional cooling systems.
2Stress or pressure
If the vent valve remains open to relieve pressure during exothermic reactions, then pressure relief is improved, but the suppressing agent escapes and cannot mitigate future thermal events
Solution Approach 1:
The vent valve is designed to close automatically after a predetermined time period following the detection of an exothermic reaction. This preliminary action ensures that the suppressing agent is retained in the battery enclosure for a sufficient duration to mitigate future thermal events, while still allowing pressure relief during the immediate reaction phase.
Solution Approach 2:
The vent valve operates in a periodic manner: open during the initial exothermic reaction to relieve pressure, then close after a set time period to retain the suppressing agent. This periodic operation pattern balances the competing requirements of pressure relief and agent retention, optimizing both immediate safety and long-term protection.
3Reliability
If a suppressing agent is dispensed into the battery enclosure, then exothermic reaction suppression is improved, but the agent may escape through an open vent valve
Solution Approach 1:
The vent valve closes automatically after a predetermined time period following the detection of an exothermic reaction. This preliminary action ensures that the suppressing agent is retained in the battery enclosure for a sufficient duration to mitigate future thermal events, while still allowing pressure relief during the immediate reaction phase.
Solution Approach 2:
The system incorporates a feedback mechanism where the state of the vent valve is controlled based on detection of exothermic reactions and elapsed time. The vent valve transitions from open to closed state based on feedback from temperature/pressure sensors and a timer, ensuring the suppressing agent is retained when needed while allowing pressure relief during active reactions.
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 system effectively reduces the risk of battery degradation by interrupting the positive feedback loop of exothermic reactions, slowing temperature rise, and maintaining the suppressing agent within the enclosure to mitigate future thermal events, thereby enhancing the longevity of the battery pack.
Implementation Method 1
The venting system includes a first vent valve that opens first to relieve pressure/temperature and then the vent closes via a solenoid to seal the enclosure
Implementation Method 2
Battery cells within an enclosure of a battery pack are prone to exothermic reactions caused by shorts or faults within the cell that lead to high pressure and temperature events
Data Source
AI summary
Methods and systems are provided for a battery system which comprises a plurality of battery cells housed inside a battery enclosure of a battery pack, a venting system, and a suppressing agent. The venting system comprises a dual-staged venting valve that equalizes pressure during normal operation of the battery system and a vent valve that opens to relieve pressure during a high pressure or temperature event. The suppressing agent is released into the enclosure of the battery pack to reduce further reactions by removing or limiting oxidants within the battery pack. A solenoid is coupled to the dual-staged venting valve and seals the dual-staged venting valve following release of the suppressing agent, allowing for the suppressing agent to remain in the enclosure for a longer period of time in order to provide increased mitigation of future thermal events in the battery enclosure.