Multi-Bridge Bus Bar for Sequential Overcurrent Cutoff
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Solution Overview
Problem
High output battery packs using nonaqueous electrolytes face safety issues due to overheating and potential explosions caused by overcurrent, which existing bus bars fail to adequately address.
Innovation Solution
A bus bar design featuring multiple bridges with varying resistance values and configurations, including different cross-sectional areas, materials, and protrusions, that sequentially fuse upon detecting an overcurrent to disconnect the electrical connection within 30 milliseconds, thereby preventing further current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single bridge is used in the bus bar, then the structure is simple, but the overcurrent protection is insufficient and may cause battery explosion
Solution Approach 1:
The bus bar is divided into multiple bridges (first bridge, second bridge, third bridge) with different resistance values instead of using a single bridge. This segmentation allows sequential fusion of bridges during overcurrent events, providing staged protection and improving reliability while distributing the protective function across multiple components.
Solution Approach 2:
Each bridge is designed with different local properties, specifically different resistance values (R1, R2, R3 where R1 < R2 < R3). This local quality differentiation ensures that bridges fuse in a specific sequence during overcurrent events, with the lowest resistance bridge fusing first, providing controlled protection while maintaining overall system reliability.
2Reliability
If multiple bridges with different resistance values are used, then overcurrent protection is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention varies the resistance parameter of each bridge (R1, R2, R3) to achieve sequential fusion characteristics. By controlling the resistance values of different bridges, the system achieves staged overcurrent protection. This parameter variation can be implemented through different cross-sectional areas, lengths, or materials of the bridges, providing manufacturing flexibility while maintaining the protective function.
3Reliability
If bridges are designed with different cross-sectional areas, then resistance values vary for better protection, but manufacturing precision requirements increase
Solution Approach 1:
The invention implements resistance value differentiation by varying the cross-sectional area parameter of each bridge. The first bridge has a larger cross-sectional area than the second bridge, which in turn has a larger area than the third bridge. This geometric parameter variation directly controls the resistance values (R1 < R2 < R3) to achieve sequential fusion protection.
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 bus bar effectively cuts off overcurrents quickly, reducing the risk of overheating and explosions by distributing the current across multiple bridges, enhancing safety and extending the battery module's life without the need for additional protection circuits.
Implementation Method 1
When the overcurrent flows, the battery module is heated, such that an internal temperature of the battery module rapidly rises. In addition, rapid temperature rise causes an electrolyte decomposition reaction
Data Source
AI summary
A bus bar includes terminal portions disposed at both ends, respectively; a plurality of bridges disposed between the terminal portions to electrically connect the terminal portions, and to be sequentially fused when an overcurrent flows. The plurality of bridges may be configured to have different resistance values, respectively.