Thermal runaway in electric vehicle battery packs presents a fundamental challenge: a single cell failure can cascade through adjacent cells at temperatures exceeding 800°C, with gas evolution rates reaching 20 L/min per cell during critical phases. The transition from localized heating to full thermal runaway typically occurs within 30-60 seconds, leaving minimal response time before propagation begins.

The engineering challenge lies in detecting early-stage thermal anomalies and implementing isolation mechanisms that can contain cell-level failures before they propagate through the pack's thermal and electrical pathways.

This page brings together solutions from recent research—including dual battery management system architectures with fault-tolerant operation, selective cell disconnection strategies, hierarchical power distribution systems with dynamic insulation monitoring, and wireless multi-agent monitoring with real-time fault isolation. These and other approaches provide practical implementations for automotive engineers seeking to enhance battery safety without compromising energy density or system performance.

1. Dual Battery Management System Architecture with Inter-BMS Communication for Fault-Tolerant Operation in Electric Vehicles

ZOOX INC, Zoox, Inc., 2024

Redundant battery management system architecture for electric vehicles that enables fault-tolerant operation under load conditions. The system comprises two battery management systems (BMS) that communicate with each other and with the vehicle's electrical control system. Each BMS monitors its own state and the state of its paired BMS, determining operating limits based on both individual battery health and system performance metrics. The system then dynamically adjusts system parameters to maintain safe operating conditions, including torque levels, voltage levels, and motor performance. This architecture enables the vehicle to continue operating safely even when one BMS fails, while the other BMS continues to manage the vehicle's electrical systems.

2. Battery System with Selective Cell Disconnection and Inter-String Voltage Equalization for Fault Tolerance

ROBERT BOSCH GMBH, 2024

Operating a battery system for electric vehicles that allows fault tolerance without sacrificing capacity or redundancy. The battery system has parallel strings, each with one or more modules containing series-connected cells. Cells and modules can be selectively switched on/off. If a cell fault occurs, only the faulty cell is disconnected. The string with the faulty cell is not switched off. Instead, it's charged from the other strings during regenerative braking until voltage equalization. This avoids wasting intact cells and maintains capacity.

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3. Battery Management System with Switching Strategy for State-of-Charge and Voltage Condition Monitoring

GM GLOBAL TECH OPERATIONS LLC, 2024

Battery management system for electric vehicles that detects and controls battery degradation through advanced monitoring of state-of-charge (SOC) and voltage conditions. The system employs a unique switching strategy that identifies battery cells with the lowest state-of-charge values when voltage conditions are detected, and connects these cells to the positive terminal. This approach enables proactive management of battery health by prioritizing cells with the most critical state-of-charge values during charging and discharging phases.

4. Hierarchical High-Voltage Battery System with Dynamic Insulation Resistance Monitoring and Selective Segment Isolation

AVL LIST GMBH, 2023

High-voltage battery system for commercial vehicles that enables selective isolation of critical segments through dynamic monitoring of insulation resistance. The system employs a hierarchical power distribution architecture with separate segments connected by switchable connecting lines. An insulation monitor continuously monitors the system's insulation resistance, triggering segment disconnection when the value falls below predetermined thresholds. This selective isolation enables targeted maintenance and shutdown of critical segments while maintaining system integrity. The system can be configured to prioritize high-priority segments, with lower-priority segments automatically disconnected in case of insulation failure.

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5. Battery System with Parallel-Connected Modules and Independent Strand Control for Fault-Tolerant Voltage Management

BOSCH GMBH ROBERT, 2022

Operating a battery system for electric vehicles that enables fault-tolerant operation by dynamically managing voltage levels across the battery pack. The system comprises battery modules connected in parallel, with each module comprising battery cells connected in series and/or parallel. The battery pack is divided into independent strands, each with its own battery modules, allowing for independent control of each strand. The system detects faults in individual battery cells and modules, and automatically adjusts voltage levels across the pack to maintain optimal operating conditions. This enables fault-tolerant operation while maintaining the pack's overall voltage level, allowing for reliable traction supply even in the presence of individual cell or module faults.

6. Power Management Circuit for Isolating Short-Board Cells in Energy Storage Systems

AOPU NEW ENERGY CO LTD, 2021

A power management system for energy storage power stations that enables efficient operation of short-board cells by isolating them from the main battery pack. The system comprises a circuit with two contacts for each battery cell, where one of the contacts is connected between the positive and negative terminals of each cell. This configuration enables the removal of a short-board cell without powering down the entire battery pack, while maintaining system safety.

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7. Battery System with Dual-Level Measurement Comparison for Fault Detection

BOSCH GMBH ROBERT, 2021

Operating a battery system with enhanced fault detection capabilities through a novel method that compares battery cell measurements across module and pack levels. The system employs both module-internal monitoring units and pack-level analysis to detect anomalies in battery cell voltages, state of charge, and overall system performance. By comparing measurements from both levels, the system can identify potential module-level faults before they propagate to the pack level, enabling early detection and potential corrective action.

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8. Battery System Isolation Device with Complex Network Control for Fault Detection and Isolation in Electric Vehicles

UNIV CHONGQING, 2021

Battery system safety isolation device and control method for electric vehicles through complex network control. The device integrates battery packs into a power system through series and parallel connections, with each pack connected in parallel to a backup circuit. The system comprises current sensors, control switches, and backup switches for each pack, along with vehicle load and battery management systems. The device monitors battery voltage, current, and temperature data against predefined thresholds to identify faults. The control switches and backup switches are automatically controlled to isolate the faulty battery, preventing system-wide failure and enabling precise fault isolation.

9. Framework for Safety Evaluation of Power Batteries in Cascade Utilization with Standardized Testing Protocols

STATE GRID CORP CHINA, 2021

Standardized safety evaluation framework for power batteries in cascade utilization, addressing the unique challenges of long-duration battery operation. The method assesses battery performance under controlled conditions before deployment, leveraging standardized testing protocols to evaluate degradation patterns and environmental influences. This comprehensive approach enables the development of reliable safety standards for cascaded battery applications, ensuring the long-term reliability and safety of battery systems.

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10. Wireless Multi-Agent Battery Management System with Real-Time Monitoring and Fault Isolation

UNIV CHONGQING POSTS & TELECOM, 2021

A wireless multi-agent-based battery management system that enables real-time monitoring of individual battery states, in-situ temperature measurement, and automatic isolation of faulty batteries in battery packs. The system employs wireless communication through multiple agents to collect and transmit data from individual batteries, while maintaining precise temperature monitoring and real-time fault detection capabilities. This enables independent battery management and control, with each battery able to operate independently without affecting the overall system.

11. Battery Management System with Parallel-Connected Isolated DC-DC Converters for Independent Module Failure Detection and Replacement

YANGZHOU BELLSTONE TECH CO LTD, 2021

Battery management system for cascade battery systems that enables independent module failure detection and replacement while maintaining system operation. The system comprises isolated DC-DC converters for each battery module, which are connected in parallel to the DC bus. Each module is connected to an isolated DC-DC converter that is also connected to the DC bus. The battery management unit monitors the state of charge and health of all modules, and when a module fails, it can independently replace the faulty module without disrupting system operation. This enables the system to maintain power output while addressing module failures through selective replacement.

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12. Distributed Battery Management System with Dynamic Fault Isolation and Component Disconnection

DILU TECH CO LTD, 2020

Distributed battery management system for automotive power systems that enables fault-tolerant operation by dynamically disconnecting power supplies from affected components when a single point of failure occurs. The system monitors sub-power supply systems and their associated loads, detects component failures, and automatically disconnects power supplies from the affected components while maintaining system safety. This approach prevents cascading failures by isolating the affected power supply from the entire system, thereby preserving critical electrical loads and preventing overall system failure.

13. Energy Storage System with Cell-Level Fault Isolation and Continuous Operation Mechanism

WANG JING, 2019

Energy storage system with fault isolation capability that enables continuous operation without system-wide shutdown. The system comprises a battery pack with multiple cells connected in series and/or parallel, along with a monitoring module that continuously tracks battery health parameters. When a cell fails, the monitoring module automatically isolates the faulty cell without requiring system-wide shutdown, allowing the system to continue operating while the faulty cell is repaired. The monitoring module employs advanced algorithms to detect and isolate faults, ensuring uninterrupted energy supply while maintaining system safety.

14. Battery Management System with Integrated Individual Cell Monitoring and Fault Detection Mechanism

BOSCH GMBH ROBERT, 2019

Battery management system for electric vehicles that enables rapid detection of battery faults through integrated monitoring of individual battery cells. The system comprises a battery control unit that continuously monitors each battery cell in the string, and a module control unit that controls the battery modules within the string. When a cell's current exceeds predetermined limits, the control unit sends a wake-up signal to the battery control unit, which automatically disconnects the affected string. This enables quick and efficient fault detection and isolation of battery cells, reducing overall system downtime and improving overall system reliability.

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15. Battery Management System for Selective Disconnection of Faulty Series Packs in Electric Vehicles

Beijing Borgward Automobile Co., Ltd., BEIJING BORGWARD AUTOMOBILE CO LTD, 2019

Power battery management system for electric vehicles that enables rapid fault detection and removal of series battery packs. The system employs a unique approach where the faulty series pack is disconnected from the remaining healthy packs, allowing complete removal without affecting the overall battery voltage. This approach eliminates the traditional series-parallel configuration limitations, enabling precise fault detection and removal of individual series packs while maintaining overall battery health.

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16. Parallel-Connected Battery Pack with Integrated Current Interrupting Device for Series Circuit Protection

BYD CO LTD, 2019

Battery system and electric vehicle that prevents series circuit failure due to abnormal interrupting device operation. The system features a parallel-connected battery pack with a current interrupting device, where each pack contains two identical batteries connected in parallel. The current interrupting device is integrated into the pack design, eliminating the need for separate interrupting devices in each battery cell. This configuration ensures reliable protection of the entire series circuit when an interrupting device malfunctions, rather than disconnecting individual cells.

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17. Battery System with Series Loop and Integrated Current Interrupting Device for Overcharge Prevention

BYD COMPANY LTD, 2019

Battery system and electric vehicle that prevent soft pack battery overcharging through a novel configuration. The system comprises a series loop containing a soft pack battery and a first single battery connected in series with the soft pack battery. An additional current interrupting device is integrated into the first single battery. This configuration enables the system to automatically detect and interrupt overcharging currents in the series loop, protecting the soft pack battery from damage.

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18. Battery System with Integrated Current Interruption Mechanism in Cell Casing

BYD CO LTD, 2019

Battery system and electric vehicle that prevents soft pack battery overheating through an intelligent current interruption mechanism. The system incorporates a current interrupting device that automatically disconnects the battery when abnormal conditions are detected, such as overcharging. This device is integrated into the battery cell casing and communicates with the internal gas to prevent overheating. The device is designed to respond quickly to abnormal conditions, ensuring safe operation of both the battery and the vehicle.

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19. Battery System with Series Loop Parallel Pack Configuration and Selective Current Interruption Mechanism

BYD Company Limited, BYD COMPANY LTD, 2018

Battery system and electric vehicle that prevent series circuit failure due to abnormal current interruption. The system comprises a series loop with multiple battery packs connected in parallel, each containing two identical battery cells. A single cell in the series loop has a current interruption device that can be triggered by abnormal conditions. The system ensures that the interruption device only activates when the cell is in a normal state, preventing unintended circuit disconnection.

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20. Distributed Battery Pack System with Independent Control Units for Modular Management

HUAWEI TECHNOLOGIES CO LTD, 2018

Distributed battery pack power supply system and charging control method to enhance vehicle power system reliability through modular battery management. The system enables independent charging and discharging of battery packs through separate control units, while maintaining continuous power supply to critical systems. This configuration ensures that if one battery pack fails, the other can continue to provide power without disrupting the overall system. The system also enables coordinated charging between battery packs, allowing them to share the load and maintain optimal state of charge.

21. Lithium-Ion Cell Charging Interruption Mechanism Based on Internal Pressure Threshold Detection

TOYOTA MOTOR CORP, 2018

Battery safety mechanism for lithium-ion cells that automatically stops charging when internal pressure exceeds a predetermined threshold. The mechanism detects gas generation during overcharging and interrupts the charging process when the pressure exceeds a predetermined level. This prevents further electrolyte degradation and maintains battery health during overcharging conditions.

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22. Battery Module with Gas-Filled Valve Current Interrupting Device for Overcharge Protection

BYD CO LTD, 2017

A battery module that prevents catastrophic overcharging through a novel mechanical structure. The module comprises a battery cell with an integrated current interrupting device, specifically a gas-filled valve that can be triggered by internal pressure increases. When the battery reaches an overcharge state, the gas pressure causes the valve to open, disconnecting the charging circuit. The valve is designed to be mechanically isolated from the cell's internal components and can be triggered by changes in temperature or internal pressure. This prevents the overcharge condition from triggering a catastrophic discharge event.

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23. Battery Module with Integrated Mechanical Current Interrupter and Atmospheric Pressure-Disengaged Explosion-Proof Valve

BYD CO LTD, 2017

Battery module with integrated current interruption and explosion protection that prevents battery explosion during charging. The module features a mechanical current interrupter and explosion-proof valve that can be disengaged under atmospheric pressure. The interrupter is connected to the cell's internal circuitry and the valve is positioned to interrupt the cell's electrical connection when pressure increases. The module is designed for use in electric vehicles where battery management system failures can lead to catastrophic events.

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24. Method for Battery Cell Voltage Equalization with Fault Detection and Isolation

HUIZHOU POWER SUPPLY BUREAU GUANGDONG POWER GRID CO LTD, 2017

A method for intelligent battery balancing and fault reconstruction that enables precise control of battery cell voltage and capacity while addressing potential faults. The method comprises monitoring battery voltage and detecting when it exceeds predetermined thresholds. If the voltage exceeds these thresholds, the method performs voltage equalization until the voltage drops to a normal range. During equalization, the method continuously monitors the battery's internal resistance and detects potential faults. When a fault is identified, the method isolates the faulty cell and initiates a backup battery system to replace it. This approach enables the system to maintain stable DC output voltage while addressing both voltage and capacity-related faults, thereby prolonging battery life.

25. Dynamic Battery Pack Management System with Automated Switching Between Charging and Discharging States Based on Real-Time Parameter Monitoring

DONGGUAN GREENWAY BATTERY CO LTD, 2017

Automatically managing multiple battery packs in electric vehicles by dynamically switching between charging and discharging states. The system continuously monitors battery pack parameters such as capacity, temperature, and discharge thresholds to determine optimal charging and discharging sequences. It automatically switches between charging and discharging states based on real-time conditions, ensuring safe and efficient battery management. The system eliminates the need for manual battery replacement and monitoring by automatically switching between states.

26. Dynamic Switching System for Battery String Fault Testing in Electric Vehicles

FARADAY&FUTURE INC, 2017

Adaptive fault testing of electric vehicle battery strings through dynamic switching of power bus connections. The system monitors and tests battery strings in predetermined time windows, with the ability to switch between strings while maintaining power supply. This approach enables comprehensive isolation testing of battery strings while ensuring continuous vehicle operation.

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27. Modular Control System for Selective Isolation of Abnormal Lithium-Ion Batteries in Battery Packs

NINGDE CONTEMPORARY AMPEREX TECHNOLOGY CO LTD, 2016

A method to isolate abnormal lithium-ion batteries in battery packs through a modular control system. The system comprises a switch control module, a battery detection module, and at least two switch modules. The control module monitors battery health parameters and provides control signals to the switch modules. The switch modules can be turned on or off in an alternating pattern, with the control module determining whether a battery is functioning normally based on its health parameters. This enables selective isolation of batteries with abnormal conditions, allowing the pack to continue operating while the problematic battery is replaced or recycled.

28. Battery Management System with Dynamic Current Adjustment and Multi-Parameter Monitoring for High-Current Charging

WUHU HONGJING ELECTRONIC CO LTD, 2016

Battery management system for electric vehicles that optimizes high-current charging to prevent rapid capacity loss. The system employs advanced equalization techniques that dynamically adjust charging current based on real-time battery state monitoring, including current, temperature, charge/discharge cycles, and voltage profiles. The system integrates multiple protection modules to prevent overcharging, short circuits, and low voltage conditions, while also monitoring temperature and discharge characteristics. The system's real-time monitoring enables early detection of potential capacity issues, enabling proactive intervention to prevent rapid degradation.

29. Lithium Battery Pack Monitoring System with Voltage Sensors, Microcontroller, RF Communication, and Remote Isolation Switch

ZHEJIANG CHAOWEI CHUANGYUAN INDUSTRIAL CO LTD, 2016

Intelligent monitoring system for lithium battery groups to improve safety and prevent issues like overcharging and short circuits. The system uses a battery monitoring device inside the battery pack with voltage sensors, microcontroller, and RF communication. It connects to a switch to isolate the pack terminals. When issues arise like overvoltage or short circuits, the monitoring device detects it and sends an alert via RF to a central control. The control can then remotely cut off power to the pack through the switch.

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30. Battery Management System with Capacitance-Based Monitoring for Series Lithium Battery Packs

LIAOCHENG UNIVERSITY, 2015

A battery management system for electric vehicles with series lithium batteries that provides accurate charging, discharging, and life estimation. The system uses hardware and software to monitor individual battery voltage, current, and temperature, as well as the overall battery pack. It calculates charging/discharging equalization, matching degree between batteries, and battery life estimates using capacitance measurements. This allows optimized charging, balancing, and life prediction for series lithium battery packs in electric vehicles.

31. Sealed Secondary Battery with Adaptive Pressure-Sensitive Deformation Mechanism

TOYOTA JIDOSHA KABUSHIKI KAISHA, 2015

Sealed secondary battery with enhanced pressure management for current interruption mechanisms. The battery incorporates a pressure-sensitive mechanism that dynamically adjusts its deformation response based on internal pressure changes during charging and discharging. This adaptive pressure control enables consistent current interruption while maintaining reliable operation over extended battery life.

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