Battery Pack Protective Circuit for Switch Failure Isolation
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Solution Overview
Problem
Conventional battery packs face safety concerns due to unintentional currents causing thermal runaway, especially when switches fail, leading to catastrophic failures and high costs associated with pyro fuses and additional components.
Innovation Solution
A protective circuit comprising a plurality of switches connected in parallel with the battery pack and a fusing unit in series, controlled by a motor control unit (MCU) to detect and actuate the fusing unit based on switch operation states, preventing unintentional currents and reducing the need for replacing the battery pack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pyro fuses are used with switches to protect against unintentional currents, then safety is improved, but device complexity and cost increase due to additional components and extensive reinstallation requirements
Solution Approach 1:
The fuse is integrated directly into the switch assembly, combining two previously separate protective components into a single unified unit. This merging eliminates the need for separate fuse installations and reduces the number of discrete components in the circuit, thereby improving safety while reducing device complexity.
Solution Approach 2:
The integrated switch-fuse assembly serves multiple functions simultaneously: the switch provides circuit control and isolation, while the integrated fuse provides overcurrent protection. This multi-functional design eliminates the need for separate protective devices, reducing both device complexity and installation requirements while maintaining comprehensive safety.
2Reliability
If pyro fuses are used with switches to protect against unintentional currents, then safety is improved, but cost increases due to additional components and reinstallation requirements
Solution Approach 1:
By integrating the fuse into the switch assembly during manufacturing, the patent eliminates the need for separate fuse procurement, installation, and potential reinstallation. This consolidation reduces overall manufacturing costs while maintaining the safety benefits of fuse protection.
Solution Approach 2:
The integrated switch-fuse assembly is designed to be self-contained and self-protecting, requiring no additional protective components or complex installation procedures. This self-service design simplifies manufacturing processes and reduces costs associated with assembly and potential future reinstallation.
3Ease of operation
If switches are used to control current flow in battery packs, then operational control is improved, but reliability deteriorates when switches fail shorted, leading to loss of control and potential thermal runaway
Solution Approach 1:
The integrated fuse provides a pre-configured safety mechanism that automatically activates when abnormal current conditions occur. This beforehand cushioning ensures that even if the switch fails, the fuse will blow to protect the battery pack, maintaining reliability while preserving operational control during normal operation.
Solution Approach 2:
The fuse acts as an intermediary protective element between the switch and the battery pack. When the switch fails shorted, the fuse serves as a backup control mechanism that can interrupt current flow, thereby maintaining system reliability while allowing the switch to continue providing operational control under normal conditions.
Data Source
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AI summary
The present subject matter relates to a protective circuit (200) for a battery pack (102) . According to aspects illustrated herein, the battery pack (102) includes a of a plurality of cells. A protective circuit (200) for a battery pack (102) is disclosed. The protective circuit includes a plurality of switches (202-1, 202-2) that are connected in parallel with the battery pack. The plurality of switches (202-1, 202-2) may be controlled by a motor control unit, MCU (112) and, at least one fusing unit 106 is connected to the plurality of switches (202-1, 202-2) in series. The MCU (112) is configured to actuate the fusing unit (106) based on detection of a state of operation of any or a combination of the plurality of switches (202-1, 202-2).