Battery String Thermal Runaway Detection and Isolation
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Solution Overview
Problem
Existing battery monitoring systems fail to effectively detect thermal runaway conditions in battery strings, which can lead to catastrophic failures and safety hazards, especially in backup power systems where the condition of batteries during non-active usage is often unknown due to infrequent power outages.
Innovation Solution
A battery monitoring system comprising a current sensor and a controller that measures the battery string current and compares it with a threshold value to determine if a thermal runaway condition exists, with a switch to isolate the affected battery string from the rest of the system, using a software program to automate the isolation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional battery monitoring systems are used to monitor individual batteries, then battery status can be tracked, but thermal runaway conditions cannot be effectively detected and the system lacks automatic isolation capability
Solution Approach 1:
The patent divides the battery system into multiple independently monitorable battery strings, each equipped with its own current sensor and isolation switch. This segmentation allows thermal runaway detection in one string without affecting others, improving reliability while maintaining manageable system complexity through modular architecture.
Solution Approach 2:
The patent introduces a controller as an intermediary that receives current sensor signals, processes them to detect thermal runaway conditions, and activates isolation switches. This intermediary component centralizes the detection logic and coordination, simplifying the overall system structure while enabling sophisticated thermal runaway detection and automatic isolation functions.
2Loss of information
If battery monitoring is performed during non-active usage periods, then battery condition can be known, but this requires continuous monitoring capability that increases system complexity
Solution Approach 1:
The patent implements continuous current monitoring through current sensors that operate throughout all battery states (charging, discharging, and standby). This continuous measurement capability ensures battery status information is available during non-active periods without requiring separate monitoring modes, maintaining information continuity while using a unified simple monitoring architecture.
Solution Approach 2:
The monitoring system uses the battery's own operating current as the monitoring parameter, eliminating the need for separate sensing systems. The same current that charges or discharges the battery is measured by current sensors to detect thermal runaway conditions, allowing the system to monitor itself using its inherent operational parameters without adding complex external monitoring infrastructure.
3Object-affected harmful factors
If automatic isolation of thermal runaway battery strings is implemented, then safety is improved, but this requires additional components and control logic
Solution Approach 1:
The patent pre-configures isolation switches in series with each battery string and programs the controller with thermal runaway detection criteria before operation. When thermal runaway is detected, the controller immediately activates the corresponding isolation switch to disconnect the affected string. This preliminary preparation of isolation mechanisms and detection criteria enables rapid automatic response that prevents thermal runaway propagation while using straightforward switch-and-controller components.
Solution Approach 2:
The patent extracts the potentially harmful battery string exhibiting thermal runaway from the overall system by activating isolation switches that physically disconnect it. This extraction removes the hazard source from the battery system, preventing propagation to other strings while maintaining the simplicity of the solution through direct electrical isolation rather than complex containment or mitigation systems.
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 detects thermal runaway conditions and isolates the affected battery string, preventing potential catastrophic failures and ensuring the safety of the remaining components and personnel by automatically disconnecting the battery string during a thermal runaway event.
Implementation Method 1
a current sensor communicating with a controller, and a status display. The current sensor is disposed so as to measure the battery current in a battery string
Implementation Method 2
A storage battery has an internal impedance, which includes resistive, inductive and capacitive components. When the battery is discharging, only DC is involved and the resistive component of the impedance is of interest as the discharge current produces a voltage drop across the internal resistance of the battery in accordance with Ohm's law
Data Source
AI summary
A system and method for monitoring the status of a system of battery strings is described. The battery string current is measured by a current sensor urged into contact with a metallic element in which the battery string current is flowing. The time history of the battery string current and voltage is interpreted to determine whether the battery string is discharging, charging or in a fully charged state. A moving average current in the charging state is used to establish a threshold for determining whether a thermal runaway condition exists. The moving average is maintained at the value that existed at a time when the battery string has been disconnected from the system current bus.