Internal Series Battery Layout for Energy Density and Thermal Safety
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Solution Overview
Problem
Conventional series-connected secondary batteries face challenges in achieving high energy density and safety performance due to the risk of thermal runaway and mechanical instability.
Innovation Solution
The internal series battery design includes battery units with varying energy densities, where the first battery unit has a higher energy density than the second, and employs specific active materials and electrolytes to balance thermal and mechanical stability, connected through intermediate current collectors for efficient stacking and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If multiple secondary batteries are connected in series to increase energy density and power density, then the energy density and power density are improved, but the risk of thermal runaway increases and mechanical safety requirements become more stringent
Solution Approach 1:
The battery system is divided into multiple battery units (first battery units and second battery units) with different energy densities. High energy density battery units are segmented and placed at specific positions (not at both ends), while safety-focused units are positioned at the ends. This segmentation allows the system to achieve high overall energy density while maintaining thermal safety through strategic spatial distribution.
Solution Approach 2:
Different regions of the battery system are assigned different quality characteristics. The first battery units have higher energy density optimized for performance, while the second battery units have lower energy density optimized for thermal stability. This local quality differentiation ensures that high energy density is achieved where needed while thermal safety is maintained at critical positions.
2Use of energy by moving object
If multiple secondary batteries are connected in series to meet increasing energy density demands, then the energy density is improved, but the mechanical safety requirements become more stringent
Solution Approach 1:
The series-connected battery system is segmented into different types of battery units with varying energy densities. By placing lower energy density units at the end positions and higher energy density units in intermediate positions, the system achieves high overall energy density while the end units provide mechanical safety buffers that reduce structural stress and improve overall mechanical reliability.
Solution Approach 2:
Different mechanical safety characteristics are assigned to different locations within the battery system. The second battery units at the ends are designed with lower energy density to provide enhanced mechanical stability and safety margins at the structural boundaries, while the first battery units in the middle are optimized for maximum energy density where structural support is more robust.
3Use of energy by moving object
If battery units with high energy density are used to achieve high theoretical energy density, then the energy density is improved, but the thermal stability deteriorates
Solution Approach 1:
The patent applies local quality by assigning different energy density characteristics to different battery units based on their positions in the series module. First battery units with higher energy density are placed in intermediate positions where thermal management is more effective, while second battery units with lower energy density and better thermal stability are placed at the ends. This spatial differentiation of quality allows the system to achieve high theoretical energy density while maintaining thermal stability through strategic positioning of high and low energy density units.
Data Source
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AI summary
This application provides an internal series battery. The internal series battery includes a series module, a positive current collector, and a negative current collector. The series module includes battery units and intermediate current collectors. The number of the battery units is greater than or equal to 3. Each of the battery units includes a positive active material layer, a solid electrolyte layer, and a negative active material layer that are stacked. Each of the intermediate current collectors is disposed between the corresponding two adjacent battery units, and the two adjacent battery units are connected in series through the intermediate current collector. The positive current collector is located at one end of the series module and is electrically connected to the positive active material layer of the battery unit at the end. The negative current collector is located at the other end of the series module and is electrically connected to the negative active material layer of the battery unit at the end. The battery units include a first battery unit and a second battery unit. An energy density of the first battery unit is the same as an energy density of any one of the battery units at two ends of the series module. An energy density of the second battery unit is different from energy densities of the battery units at the two ends of the series module.