EV Battery Bus Bar Arrangement for Thermal Balancing
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Solution Overview
Problem
Conventional lithium ion battery bus bar arrangements in electric vehicles face challenges in thermal management, as long bus bars generate excessive heat and struggle to efficiently transfer heat to cooling fins, leading to temperature imbalances and potential safety hazards.
Innovation Solution
A novel bus bar arrangement featuring first and second pairs of modules with outer and inner bus bars that are strategically positioned to facilitate even thermal energy distribution, with outer bus bars on lateral sides and inner bus bars near the center, allowing for effective thermal balancing and heat transfer to cooling fins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long bus bars are used to connect battery cells, then electrical connectivity is achieved, but excessive heat is generated and thermal management becomes difficult
Solution Approach 1:
The bus bar system is segmented into multiple shorter bus bars instead of using one long bus bar. Each bus bar connects adjacent battery cells, distributing the electrical connectivity function across multiple segments. This segmentation reduces the length of individual bus bars, thereby reducing heat generation while maintaining overall electrical connectivity across the battery pack.
2Ease of manufacture
If bus bars are positioned far from cooling fins, then electrical connections are simplified, but heat transfer to cooling fins becomes inefficient
Solution Approach 1:
The bus bars are strategically positioned at different locations relative to cooling fins based on local thermal requirements. Bus bars connecting cells near cooling fins are positioned closer to maximize heat transfer, while bus bars in other areas maintain optimal electrical connection paths. This local optimization ensures efficient heat transfer where needed without compromising overall connection simplicity.
3Adaptability or versatility
If temperature variations between cells are allowed, then battery pack flexibility is maintained, but imbalanced performance and safety issues occur
Solution Approach 1:
The bus bar arrangement incorporates thermal management considerations by positioning bus bars to facilitate heat transfer in the thermal dimension while maintaining electrical connectivity in the electrical dimension. By strategically locating bus bars near cooling fins and optimizing their thermal pathways, the system addresses temperature variations across different spatial dimensions, ensuring uniform cell temperatures without sacrificing battery pack flexibility.
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 arrangement enhances thermal management by distributing heat evenly across the battery module, reducing temperature differences between cells and improving overall battery pack performance and safety by ensuring optimal temperature ranges.
Implementation Method 1
heat transfer from the center region of each bus bar toward the end regions of each bus bar where the bus bar is coupled to a cooling fin
Data Source
AI summary
A battery for an electric vehicle includes first and second pairs of modules in electrical communication with each other. The first pair of modules includes a first module and a second module. The second module is in electrical and thermal communication with the first module via a first plurality of outer bus bars. The second pair of modules includes a third module and a fourth module. The fourth module is in electrical and thermal communication with the third module via a second plurality of outer bus bars. The first and second pairs of modules are coupled to each other via a first inner connecting bus bar and a second inner connecting bus bar proximate to a center region of each of the second and third modules.