Battery Cell Pressure Sensing for Swelling-Based Fire Prevention
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Solution Overview
Problem
Conventional battery management systems fail to effectively monitor and mitigate internal pressure changes in battery cells, which can lead to swelling and potentially result in battery fires.
Innovation Solution
The implementation of a battery module with integrated swelling/pressure sensors that detect abnormal swelling or pressure changes in battery cells, triggering an alarm and automatically halting the operation of the battery rack to prevent further charging or discharging until the affected cell is replaced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional battery management systems only monitor voltage and temperature, then the system complexity is low, but the ability to detect internal pressure changes and prevent battery fires is insufficient
Solution Approach 1:
The patent integrates a pressure sensor inside the battery cell structure itself, nesting the sensing element within the cell's existing architecture. This allows pressure monitoring capability to be embedded without adding external monitoring equipment, thus improving reliability while minimizing increases in system complexity
Solution Approach 2:
The patent replaces conventional mechanical pressure sensing methods with optical or electromagnetic sensing techniques. The pressure sensor uses non-mechanical fields to detect internal pressure changes, enabling more precise monitoring of battery cell conditions while reducing the complexity associated with mechanical linkages and moving parts
2Reliability
If pressure sensors are integrated into battery cells to detect swelling, then battery fire prevention is improved, but the manufacturing complexity increases
Solution Approach 1:
The pressure sensor is pre-integrated into the battery cell during the manufacturing process rather than being added as a post-assembly component. This preliminary integration allows the sensing element to be installed while the cell structure is still being formed, simplifying the overall assembly process and reducing manufacturing complexity despite the added functionality
Solution Approach 2:
The patent designs the pressure sensor to serve multiple functions: detecting internal pressure changes, monitoring cell swelling, and providing early warning of potential failure modes. This multi-functionality consolidates several monitoring capabilities into a single integrated component, reducing the number of separate parts and assembly steps required
3Reliability
If high frequency AC power is used for cell balancing, then isolation transformers can be used improving safety, but the power conversion complexity increases
Solution Approach 1:
The patent introduces high frequency AC power as an intermediary medium in the cell balancing process. By converting DC power to high frequency AC, passing it through isolation transformers for galvanic isolation, and then converting back to DC, the system achieves electrical isolation safety. The high frequency AC serves as a temporary carrier that enables the use of compact, efficient isolation transformers
4Temperature
If water cooling plates are integrated into battery modules, then thermal management is improved, but the device complexity and water management requirements increase
Solution Approach 1:
The patent merges the cooling function with the structural support function by integrating water cooling plates directly into the battery module housing. The cooling plates serve dual purposes: providing thermal management pathways and maintaining mechanical support for the battery cells. This consolidation reduces the number of separate components and simplifies the overall system architecture
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 effectively prevents battery fires by detecting and responding to abnormal pressure changes in battery cells, ensuring the safety of the battery system and preventing damage.
Implementation Method 1
a sensor that detects swelling of a battery cell
Implementation Method 2
Using high frequency AC power permits the use of isolation transformers as a part of the cell balancing circuit
Implementation Method 3
a top cover that collects water and directs this water to plates of the battery module to cool the battery
Implementation Method 4
a water fire suppression system having a cascading water flow among the battery modules, which provides cooling in the event of a battery cell fire
Implementation Method 5
an exhaust duct to remove gases and/or heat and direct these gases and/or heat outside of the room, container, building, etc. that houses the battery rack
Data Source
AI summary
Sensors and circuits for batteries are provided that prevent battery fires. The sensors and circuits are part of a battery management system that detects battery cell swelling and changes in the internal pressure of battery cells and removes the battery cells from service before they vent and catch on fire or explode. The sensors and circuits continually monitor every battery cell for swelling/increases in internal pressure that are indicative of the formation of flammable and explosive gases within the battery cells, and a battery management system that includes one or more of the sensors and circuits removes battery cells with issues from service before they vent and catch on fire or explode.