Fluid-Filled Pressure Sensing Cell for Battery Pack Compression Monitoring
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Solution Overview
Problem
Existing battery management systems struggle to reliably detect upcoming thermal runaway and evaluate the state of health and safety of battery packs with linearly stacked cells, due to limitations in sensing compression loads and temperature distributions within the pack.
Innovation Solution
A pressure sensing cell is introduced, comprising a flexible pouch container filled with fluid, a pressure-sensitive member with electric pins, and electric lines. This cell is designed to sense the compression load applied to the battery pack and provide real-time data on compression load and temperature, enabling early detection of thermal runaway and continuous monitoring of battery health.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid structures such as metal or hard plastic housings are used to counter expansions, then structural strength is improved, but measurement precision of compression load deteriorates
Solution Approach 1:
The patent introduces a separate pressure sensing cell as an independent component within the battery pack structure. This sensing cell is distinct from the main rigid housing, allowing the housing to maintain its structural strength while the dedicated sensing cell provides accurate compression load measurements through its compliant design.
Solution Approach 2:
The pressure sensing cell acts as an intermediary element between the rigid battery pack housing and the measurement system. It transmits compression load information from the battery cells to the measurement device while maintaining the structural integrity of the overall pack, resolving the conflict between rigid housing requirements and measurement accuracy.
2Reliability
If elastic materials such as foams are used to absorb swelling, then reliability is improved, but measurement precision of compression load deteriorates
Solution Approach 1:
The patent separates the swelling absorption function (performed by elastic materials) from the measurement function (performed by the pressure sensing cell). The sensing cell is designed to measure compression load independently, while elastic materials provide reliable swelling accommodation without interfering with measurement accuracy.
Solution Approach 2:
The pressure sensing cell serves as an intermediary that accurately transmits compression load information despite the presence of elastic materials in the system. It enables precise measurement even when elastic materials are used to absorb swelling, resolving the contradiction between reliability and measurement precision.
3Measurement precision
If compression pads are used to ensure slight compression, then state of health evaluation is improved, but device complexity increases
Solution Approach 1:
The pressure sensing cell performs multiple functions: it monitors compression load, evaluates state of health, detects thermal runaway, and tracks battery pack aging. By consolidating these functions into a single multi-functional sensor, the patent improves measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The pressure sensing cell automatically provides comprehensive battery pack monitoring data that enables state of health evaluation. The sensor self-services by continuously measuring compression load and providing data to the battery management system, reducing the need for additional complex monitoring systems.
4Reliability
If multiple sensors are added to monitor compression load and temperature, then reliability is improved, but device complexity increases
Solution Approach 1:
The pressure sensing cell is designed as a multi-functional sensor that simultaneously monitors compression load, temperature, and other battery pack conditions. This consolidates multiple sensing functions into a single device, improving detection reliability without proportionally increasing device complexity.
Solution Approach 2:
The patent merges compression load sensing, temperature monitoring, and state of health evaluation functions into an integrated pressure sensing cell. By combining multiple sensing capabilities in one device, the system achieves high reliability while minimizing the increase in device complexity.
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 pressure sensing cell allows for early detection of thermal runaway by sensing rising compression loads, supports continuous monitoring of battery pack conditions, and enhances the evaluation of state of health and safety of the battery pack, thereby improving safety and reliability in battery-powered systems.
Implementation Method 1
The fluid-filled flexible pouch container has a plurality of electric feedthroughs. The at least one pressure-sensitive member comprises a plurality of electric pins and is arranged within the flexible pouch container
Implementation Method 2
The at least one pressure-sensitive member comprises a plurality of electric pins and is arranged within the flexible pouch container. The plurality of electric lines connects the plurality of electric feedthroughs and the plurality of electric connections
Data Source
AI summary
A pressure sensing cell for use in a battery pack that has a plurality of linearly stacked battery cells. The pressure sensing cell includes an at least partially fluid-filled and fluid-proof flexible pouch container having a plurality of electric feedthroughs, at least one pressure-sensitive member having a plurality of electric pins, that is arranged within the flexible pouch container, and a plurality of electric lines that electrically connect the plurality of electric feedthroughs and the plurality of electric pins. A battery pack is provided that includes a plurality of linearly stacked battery cells and at least one such pressure sensing cell. A method for at least one of detecting upcoming thermal runaway, supporting the evaluating of a state of safety, and supporting the evaluating of a state of health of a battery pack having a plurality of linearly stacked battery cells employs at least one such pressure sensing cell.