Battery container vents with pressure burst covers using electrical interlocks for detecting thermal events
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Solution Overview
Problem
Current thermal runaway detection techniques in battery systems often rely on pack-level architectures, requiring dedicated sensors and complex sensor placement, which increases system complexity, cost, and weight, while reducing battery capacity and driving range.
Innovation Solution
The implementation of pressure burst covers with electrified interlocks for gas vents in battery containers, which use a low-voltage interlock circuit to monitor the displacement of a pressure burst relief valve, allowing for early detection of thermal runaway events without the need for sensors on each cell or module, thereby reducing system part counts and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pack-level thermal runaway detection with dedicated sensors is used, then detection capability is improved, but system complexity and cost increase
Solution Approach 1:
The pressure burst cover serves multiple functions: it acts as both a pressure relief mechanism and a thermal runaway detection trigger. When thermal runaway occurs and pressure builds up, the cover bursts open, simultaneously relieving pressure and activating the electrical interlock circuit to signal the control module. This eliminates the need for separate dedicated sensors.
Solution Approach 2:
The patent combines the pressure relief function and thermal runaway detection function into a single integrated component (the pressure burst cover with electrical interlock). This merging of functions reduces the number of separate components needed, thereby reducing system complexity while maintaining detection capability.
2Measurement precision
If dedicated sensors and complex sensor placement are used, then detection accuracy is improved, but system cost increases
Solution Approach 1:
The pressure burst cover is a passive component that automatically activates through its own mechanical response to pressure buildup. It does not require external power, complex electronics, or active sensing mechanisms. The electrical interlock circuit is simply activated by the mechanical bursting action, making the system self-service and cost-effective.
Solution Approach 2:
The pressure burst cover is designed as a low-cost, single-use component. Once it bursts open during thermal runaway, it fulfills its detection and relief function and is replaced. This disposable nature allows for simplified manufacturing and lower cost compared to reusable, complex sensor systems.
3Measurement precision
If sensors are placed on each cell or module, then detection precision is improved, but battery capacity and driving range are reduced
Solution Approach 1:
The patent applies segmentation by placing simplified pressure burst covers with electrical interlocks at the module level rather than requiring sensors on each individual cell. This segmentation approach provides sufficient detection precision for thermal runaway events while avoiding the space and weight penalties of cell-level sensing, thereby preserving battery capacity and driving range.
4Reliability
If complex sensor systems are implemented, then detection capability is improved, but system weight and packaging volume increase
Solution Approach 1:
The patent extracts the complex sensing functionality and replaces it with a simple mechanical-electrical trigger system. The pressure burst cover with electrical interlock removes the need for heavy, complex sensor assemblies, thereby reducing system weight while maintaining essential detection capability through the burst-induced circuit activation.
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 enables fast and accurate detection of thermal runaway events, allowing for quicker mitigation, simplifies system design, reduces weight and packaging volume, and increases battery capacity, leading to improved vehicle efficiency and extended driving range.
Implementation Method 1
The electrical lead(s) may extend through or across an outer surface of the vent cover and may electrically connect to a voltage sensing device integral with or connected to a system controller
Implementation Method 2
If a battery cell or module descends into thermal runaway, it may generate a large amount of heat and gas that, in turn, create a build-up of pressure inside the battery container
Data Source
AI summary
Presented are pressure burst covers with electrical interlocks for battery vents, methods for making/using such covers, and motor vehicles equipped with such covers for detecting thermal events in lithium-class batteries. A battery assembly includes an electrochemical battery cell housed inside a battery container. The battery container includes a fluid port that evacuates therethrough cell-generated gases. A pressure burst cap is movably attached to the battery container to selectively transition from a closed position, whereat the cap covers the port, to an open position, whereat the cap partially or fully uncovers the port. An electrical interlock circuit, which is connected to a controller, includes a circuit lead that is attached to the pressure burst cap and battery container. The circuit lead holds the cap in the closed position and fails at a preset rupture force to create an open circuit signal within the electrical interlock circuit indicative of a thermal event.