Battery Pack Thermal-Zone Cell Placement for Cold Discharge Stability
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Solution Overview
Problem
Lithium-ion battery packs experience a significant reduction in energy retention rate at low temperatures due to varying heat dissipation and thermal insulation effects within the battery pack, leading to inconsistent charge and discharge performance across different battery cells.
Innovation Solution
The battery pack is designed with distinct areas for different battery cells, each with two discharge voltage plateaus, where cells with higher low-temperature energy retention rates are placed in colder areas and those with lower retention rates in warmer areas, ensuring consistent energy release and improved overall low-temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If battery cells are uniformly distributed in the battery pack, then the structure is simple and easy to manufacture, but the low-temperature energy retention rate is significantly reduced due to varying thermal conditions
Solution Approach 1:
The patent applies local quality by differentiating battery cell placement based on thermal zones within the battery pack. Cells with higher low-temperature performance are specifically positioned in colder regions (peripheral areas), while cells with standard performance are placed in warmer regions (central areas). This non-uniform distribution optimizes low-temperature energy retention by matching cell characteristics to local thermal conditions, resolving the contradiction between simple uniform structure and reliable low-temperature performance.
2Reliability
If battery cells with different low-temperature performance are placed in different temperature zones, then the low-temperature energy retention rate is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent segments the battery pack into distinct thermal zones (first area with higher temperature and second area with lower temperature). This segmentation allows for systematic placement of different cell types in appropriate zones, making the manufacturing process more manageable despite the increased complexity. By dividing the pack into defined areas with specific thermal characteristics, the assembly process can follow a structured approach rather than attempting uniform distribution.
Solution Approach 2:
The patent implements local quality by assigning specific cell performance characteristics to specific spatial locations within the battery pack. Cells with higher low-temperature performance are placed in the colder second area, while standard cells are placed in the warmer first area. This localized optimization improves overall low-temperature energy retention while maintaining a systematic manufacturing approach based on predefined thermal zones.
3Productivity
If all battery cells operate at the same discharge rate, then the control system is simple, but the overall energy release is inconsistent due to temperature variations affecting individual cell performance
Solution Approach 1:
The patent applies local quality to energy management by enabling independent control of discharge rates for different battery cell groups based on their thermal zones. The control system can adjust discharge parameters for cells in colder regions versus warmer regions, optimizing overall energy release consistency. This localized control approach improves productivity by ensuring consistent energy output across varying temperature conditions while managing control system complexity through zone-based strategies.
Data Source
AI summary
The battery pack may include a battery pack case and battery cells accommodated in the battery pack case. In each of the first battery cell, the second battery cells, and the third battery cells, when the sum of a discharge capacity corresponding to the first discharge voltage plateau and a discharge capacity corresponding to the second discharge voltage plateau is 100%, a percentage of the discharge capacity corresponding to the second discharge voltage plateau of the third battery cells may be larger than a percentage of the discharge capacity corresponding to the second discharge voltage plateau of the second battery cells, which may be larger than a percentage of the discharge capacity corresponding to the second discharge voltage plateau of the first battery cell.