Battery Pack Protection Circuit for Sneak Current Fuse Cutoff
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Solution Overview
Problem
Conventional protection circuits for secondary batteries face challenges in identifying which fuse element is cut off during an overcurrent event, leading to potential sneak currents and increased complexity, cost, and failure rates due to the symmetrical structure of self-control protectors (SCPs) and the need for multiple rectifier elements.
Innovation Solution
A protection circuit design where each protection element has two fuse elements in series, with a heater generating heat to blow the other fuse element after an overcurrent occurs, allowing for reliable identification and prevention of sneak currents without additional rectifier elements, simplifying the circuit and reducing parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple rectifier elements are added to prevent overcurrent in each SCP, then overcurrent prevention is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the overcurrent prevention function into the common ground wire that connects multiple SCPs in parallel. Instead of adding separate rectifier elements to each SCP, a single common ground wire with appropriate resistance serves all SCPs simultaneously, preventing overcurrent in the entire system through one unified protective path.
Solution Approach 2:
The common ground wire performs multiple functions: it serves as the return path for normal current flow and simultaneously acts as an overcurrent protection mechanism for all parallel-connected SCPs. This universal component replaces the need for individual protective elements for each SCP.
2Ease of manufacture
If the symmetrical structure of SCP is maintained, then manufacturing simplicity is preserved, but identification of cut-off fuse element becomes impossible
Solution Approach 1:
The patent introduces a detection circuit that acts as an intermediary to identify which fuse element has been cut off. This detection mechanism allows the symmetrical SCP structure to be maintained for manufacturing simplicity while enabling identification of the failed component through electrical measurement rather than physical inspection.
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 design effectively prevents overcurrents and sneak currents, enhancing safety, reducing device failure rates, and lowering costs by eliminating the need for additional rectifier elements and simplifying the circuit configuration.
Implementation Method 1
a heater configured to blow the fuse elements in a current-carrying process
Data Source
AI summary
Provided is a protection circuit capable of reliably preventing an overcurrent or a sneak current after cutoff to improve safety, implementing cost reduction with a device configuration simpler than conventional device configurations, and further reducing a failure rate of a device. In a protection circuit, after one of two fuse elements provided in each of a plurality of protection elements is blown due to an overcurrent flowing along a current-carrying path, a heater provided in at least one of the plurality of protection elements generates heat due to a sneak current flowing via the plurality of protection elements on the current-carrying path which is remained and blows the other of the two fuse elements provided in the at least one of the plurality of protection elements.