Mixed-Cell Battery Pack Layout for Low-Temperature Discharge
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Solution Overview
Problem
Secondary batteries used in electric vehicles experience a significant reduction in discharge power and inconsistent performance at low temperatures, such as in winter, due to increased internal resistance and varying temperature distribution across different areas of the battery pack.
Innovation Solution
A battery pack design comprising two types of battery cells with different discharge powers, where the second battery cell type has a higher discharge power at -20°C than the first type, and their spatial arrangement within the pack ensures that the second battery cells with higher discharge power are placed in outer areas to compensate for temperature differences, maintaining consistent discharge power across the pack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform battery cells are used throughout the battery pack, then manufacturing simplicity is maintained, but discharge power consistency deteriorates at low temperature due to temperature distribution variations
Solution Approach 1:
The patent applies local quality by differentiating battery cell types based on their spatial location within the battery pack. Specifically, it places high discharge power battery cells in the outer area (first region) and standard battery cells in the inner area (second region). This local differentiation addresses the temperature distribution issue where outer cells experience different thermal conditions than inner cells, thereby improving discharge power consistency across the entire pack at low temperatures.
2Reliability
If high discharge power battery cells are placed in outer areas, then discharge power consistency improves at low temperature, but device complexity increases due to differentiated cell arrangement
Solution Approach 1:
The patent applies segmentation by dividing the battery pack into distinct spatial regions - an outer first region and an inner second region - and assigning different battery cell types to each region. This segmentation strategy systematically manages the complexity by creating clear zones with specific functions, making the differentiated arrangement more manageable and implementable while achieving improved discharge power consistency.
3Power
If battery cells with different discharge powers are used, then low temperature discharge performance improves, but manufacturing precision requirements increase for cell selection and placement
Solution Approach 1:
The patent applies local quality by differentiating battery cell types based on their spatial location within the battery pack. Specifically, it places high discharge power battery cells in the outer area (first region) and standard battery cells in the inner area (second region). This local differentiation addresses the temperature distribution issue where outer cells experience different thermal conditions than inner cells, thereby improving discharge power consistency across the entire pack at low temperatures.
Data Source
AI summary
A battery pack may include a first battery cell type and a second battery cell type, wherein the first battery cell type may include n first battery cells, and the second battery cell type may include m second battery cells, with n and m being each independently selected from an integer of 1 or more, wherein the second battery cell may have a discharge power at −20° C. greater than that of the first battery cell, the difference in discharge power at −20° C. between the second battery cells and the first battery cells being ≥10 W; the percentage by number of the first battery cells in the battery cells comprised in area A may be 20% to 100%, and the percentage by number of the second battery cells in the battery cells comprised in the area B may be 5% to 100%.