Battery Pack Circuit Breaker for Swelling Safety
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Solution Overview
Problem
Lithium secondary batteries, particularly in large-sized packs, face safety concerns due to potential fires or explosions from abnormal operations like overcharge, overdischarge, and overcurrent, which existing safety systems may not adequately address, especially when the battery management system (BMS) malfunctions without power supply.
Innovation Solution
Incorporating a circuit breaker and fuse configuration that operates independently of the BMS, where the circuit breaker senses swelling of battery cells to break the fuse, thereby interrupting electrical connections and preventing overcurrent or overvoltage transmission, ensuring safety without relying on external power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a battery management system (BMS) is used to protect battery cells from overcharge, overdischarge, and overcurrent, then the safety of the battery pack is improved, but the system complexity and power supply requirements increase
Solution Approach 1:
The safety system is segmented into two independent parts: an active BMS for normal operation monitoring and a passive mechanical circuit breaker for emergency situations. This segmentation allows the complex active system to operate under normal conditions while a simple passive mechanism handles critical failures, reducing overall system complexity requirements.
Solution Approach 2:
A mechanical circuit breaker acts as an intermediary between the battery cells and the external circuit. This intermediary provides a passive safety mechanism that physically disconnects the circuit when swelling occurs, without requiring power supply or complex control logic, thus improving safety without proportionally increasing system complexity.
2Reliability
If an active controller like BMS is used to detect and control abnormal operations, then the safety response capability is improved, but the dependency on power supply increases
Solution Approach 1:
The mechanical circuit breaker is designed to be self-activating through a spring-loaded mechanism that automatically trips when battery swelling occurs. This self-service mechanism does not require external power supply or control signals, providing safety response capability independent of the BMS power status.
Solution Approach 2:
The patent replaces the electrical control system with a mechanical sensing and actuation system. The mechanical circuit breaker uses physical swelling detection and spring-loaded disconnection mechanisms, substituting electronic sensors and actuators with purely mechanical components that operate without power.
3Volume of moving object
If the battery modules are connected in tight contact or stacked adjacent to each other, then the space utilization is improved, but the heat dissipation and safety margins are reduced
Solution Approach 1:
The mechanical circuit breaker serves as a safety intermediary that compensates for the reduced safety margins caused by tight packing. By providing a passive failure mode that physically disconnects the circuit, it allows the battery modules to be placed closer together without proportionally increasing the risk, as the mechanical breaker provides an additional safety layer independent of thermal conditions.
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 configuration enhances the safety of the battery pack by mechanically interrupting electrical connections during abnormal cell swelling, preventing gas leakage or explosions, and maintaining reliability even when the BMS is non-functional, facilitating easy manufacturing and various structural applications.
Implementation Method 1
a circuit breaker mounted at an outside of at least one of the battery modules to perform electric conduction when the battery cells swell
Data Source
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AI summary
Disclosed herein is a battery pack configured such that battery modules, each of which includes a plurality of battery cells or unit modules connected to each other in series, are connected to each other in series in a state in which the battery modules are in tight contact with each other or stacked adjacent to each other, the battery pack including a fuse connected in series in an electrical connection circuit between the battery modules and a circuit breaker mounted at an outside of at least one of the battery modules to perform electric conduction when the battery cells swell, the circuit breaker being electrically connected to the electrical connection circuit to break the fuse when electric conduction is performed due to swelling of the battery cells.