3D Bus Bar Structure in Battery Packs for Uniform Load Distribution
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Solution Overview
Problem
Existing battery packs face challenges in achieving high energy density and efficient charge/discharge paths due to dead space and uneven electrical resistance, which lead to non-uniform load distribution and potential degradation.
Innovation Solution
The design incorporates a circuit board that electrically connects battery cells in a modular configuration with bus bars extending along the third direction, minimizing dead space and using a cutout portion to equalize electrical resistance, ensuring uniform load distribution across cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If battery cells are arranged in a battery module to increase output and capacity, then the energy source capability is improved, but dead space increases and energy density decreases
Solution Approach 1:
The bus bar is configured to extend in the third direction (vertical direction perpendicular to the circuit board) rather than only in the plane of the circuit board. This three-dimensional arrangement allows the bus bar to connect multiple battery cells while minimizing the horizontal space occupied, thereby reducing dead space and improving energy density while maintaining the electrical connection function for increased power output.
Solution Approach 2:
The bus bar includes multiple connection portions at intermittent positions along its length, with each connection portion connected to a respective battery cell. This segmentation allows the bus bar to efficiently connect multiple cells in a modular fashion, optimizing space utilization and reducing dead space between connections while maintaining the cumulative power output of all connected cells.
2Power
If battery cells are arranged in a battery module to increase output and capacity, then the energy source capability is improved, but the charge/discharge path becomes uneven leading to non-uniform load distribution
Solution Approach 1:
The bus bar is designed with varying cross-sectional areas along its length, with thicker sections positioned at locations with higher electrical resistance. This local quality adjustment compensates for resistance variations in different parts of the charge/discharge path, ensuring that current distributes uniformly across all battery cells despite the modular arrangement, thereby improving reliability while maintaining high power output.
3Ease of manufacture
If the bus bar is arranged in the planar direction of the circuit board, then the connection is simplified, but dead space increases and energy density decreases
Solution Approach 1:
The bus bar extends primarily in the third direction (vertical) rather than only in the planar directions (first and second directions) of the circuit board. This three-dimensional configuration reduces the horizontal footprint and dead space while maintaining electrical connectivity. The connection portions still provide simplified connections to battery cells, achieving both space efficiency and manufacturing ease.
4Ease of manufacture
If the bus bar has uniform cross-sectional area, then the manufacturing is simplified, but electrical resistance varies along the charge/discharge path
Solution Approach 1:
The bus bar features a non-uniform cross-sectional area with thicker sections strategically positioned at locations where electrical resistance is higher. This local variation in geometry compensates for resistance differences along the charge/discharge path, ensuring uniform current distribution across battery cells. While slightly more complex than a uniform design, the manufacturing remains practical and the reliability improvement is significant.
Data Source
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AI summary
A battery pack includes a plurality of battery cells, a circuit board electrically connecting the plurality of battery cells together, the circuit board extending along a first direction and a second direction, and a bus bar connected to the circuit board to form a charge/discharge path, wherein the bus bar extends along a third direction, different from the first and second directions.