Battery Pack Spacer Cooling for Electrode Temperature Uniformity
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Solution Overview
Problem
Battery packs, especially those used in hybrid electric vehicles, face reduced lifespan due to temperature variations within the electrode body caused by heat transfer from external terminals, leading to inefficient cooling and increased stress on battery cells.
Innovation Solution
The battery pack design includes a spacer with specific passage configurations and cooling efficiencies between the electrode body and case side walls, along with a strategically positioned electrode body to minimize heat transfer from external terminals, and varying cooling air flow rates and cross-sectional areas to optimize cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If battery cells are arranged with external terminals connected by busbars to increase power output, then the power output capability is improved, but temperature variation within the electrode body increases and battery cell life decreases
Solution Approach 1:
The spacer is designed with non-uniform thickness to provide localized cooling where needed. The thicker portion is positioned opposite the upper curved portion of the electrode body where heat accumulation is most severe, while the thinner portion is opposite the lower curved portion. This creates different cooling intensities at different locations, effectively addressing the temperature variation problem caused by high power output operations.
2Temperature
If cooling air is introduced between the spacer and case side wall to reduce temperature, then the cooling effect is improved, but the structural complexity increases
Solution Approach 1:
The spacer serves multiple functions simultaneously: it provides mechanical support to maintain battery cell structure, creates cooling passages for thermal management, and acts as a thermal barrier. By integrating these functions into a single component, the design achieves effective cooling without adding separate cooling structures, thus avoiding increased structural complexity.
3Duration of action of moving object
If the electrode body is positioned toward the lower end of the case to reduce heat transfer from external terminals, then temperature variation is reduced, but the cooling efficiency at the upper curved portion decreases
Solution Approach 1:
The spacer is designed with asymmetric thickness distribution to match the asymmetric heat generation pattern of the electrode body. The upper curved portion, which experiences higher heat accumulation due to its position near the external terminals, is opposed by the thicker portion of the spacer that provides enhanced cooling. The lower curved portion is opposed by the thinner portion, creating an asymmetric cooling configuration that optimizes temperature control across different electrode body regions.
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 reduces temperature variations within the electrode body, prolonging battery cell life by effectively managing heat distribution and cooling efficiency, thereby enhancing the overall performance and longevity of the battery pack.
Implementation Method 1
The spacer forms passages through which cooling air flows between the spacer and the one of the side walls
Implementation Method 2
heat will be transferred from the external terminals to the electrode body located near the external terminals
Data Source
AI summary
A battery pack includes battery cells and a spacer arranged between two adjacent battery cells. Each battery cell includes an electrode body and a case. The electrode body includes an upper curved portion, a flat portion, and a lower curved portion. The spacer presses one side wall of the case of one of the adjacent battery cells toward an inner side of the case at a part where the side wall opposes a region from the upper curved portion to the lower curved portion. The spacer forms passages for cooling air between the spacer and the side wall. A first cooling efficiency of the cooling air per unit area at a first opposing portion of the side wall that opposes the upper curved portion is less than a second cooling efficiency per unit area at a second opposing portion of the side wall that opposes the flat portion.