Battery AC Sensing for Early Thermal Runaway Detection
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Solution Overview
Problem
Existing battery management systems struggle to rapidly and cost-effectively detect anomalous conditions, particularly thermal runaway, due to the small magnitude of alternating current signals and the need for costly and late-stage detection methods like gas and pressure sensors.
Innovation Solution
A battery monitoring system incorporating an alternating current measurement sensor and a controller to process these signals, enabling rapid detection of anomalous conditions and controlling a switch to disconnect the battery system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If gas and pressure sensors are used to detect thermal runaway conditions, then the battery management system can have simpler and lower cost current sensors for normal operation, but thermal runaway is detected at a rather late stage whereby the anomalous conditions leading to thermal runaway may occur minutes before any excessive gas production has occurred
Solution Approach 1:
The patent divides the monitoring function into two separate sensing systems: one for normal DC current measurement and another for detecting AC signals associated with thermal runaway. This segmentation allows each sensor to be optimized for its specific function, enabling early thermal runaway detection without compromising normal operation monitoring capabilities
Solution Approach 2:
The patent introduces an intermediary AC coupling mechanism that allows the sensing system to detect thermal runaway conditions through AC signals while maintaining DC isolation. This intermediary approach enables the system to detect anomalies before they manifest as gas production or significant DC current changes
2Ease of manufacture
If gas and pressure sensors are used to detect thermal runaway conditions, then the battery management system can have simpler and lower cost current sensors for normal operation, but gas and pressure sensors require air-tight battery enclosures in order to be able to detect the pressure changes
Solution Approach 1:
The patent replaces the mechanical/physical sensing approach (gas and pressure sensors requiring airtight enclosures) with an electrical sensing approach that detects AC signals through coupling mechanisms. This substitution eliminates the need for complex airtight enclosure requirements while maintaining thermal runaway detection capability
3Adaptability or versatility
If costly sensing systems are used to measure both the slowly changing DC currents with a high dynamic range during normal operation as well as detecting AC currents at anomalous conditions, then both normal operation and anomalous conditions can be monitored with a single system, but the cost of the sensing system increases significantly
Solution Approach 1:
The patent segments the sensing function into two independent systems: a DC current sensor for normal operation monitoring and an AC sensing system for thermal runaway detection. This segmentation allows each sensor to be optimized for its specific frequency range and performance requirements, reducing overall system cost while maintaining versatility
Solution Approach 2:
The patent creates a dual-purpose monitoring architecture where the combination of DC and AC sensing systems provides universal coverage for both normal operation and anomalous conditions. The system achieves multi-functionality through coordinated operation of specialized sensors rather than a single expensive universal sensor
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
Enables early detection of thermal runaway and other anomalous conditions without the need for airtight enclosures, reducing costs, and allowing for additional functions like SOH tracking and Lithium-plating detection.
Implementation Method 1
an alternating current measurement sensor configured to measure an alternating voltage of one or more battery cells
Data Source
Figure 1
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Figure 3a~3d
AI summary
Battery system (100) comprising a plurality of battery cells (101) and a battery management system (104) comprising a battery management unit (106), a current sensor (110) connected to the battery management unit (106) and configured to measure a current flowing in and out a plurality of battery cells (101). The battery system further comprises a battery anomalous condition sensor (1) including an alternating current (AC) measurement sensor (2) configured to measure an alternating voltage of one or more battery cells (101), and a controller (11) configured to process the measured alternating current voltages and either provide said measured alternating voltages to the battery management system (104) to determine an anomalous condition or to process the voltage measurement signal to detect an anomalous condition of the battery and to control a switch (112) to disconnect the battery system (100) from external systems (103) in the case of detection of an anomalous battery condition.