Internal Series Battery With Mixed Energy-Density Units for 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 safety concerns.
Innovation Solution
The internal series battery design incorporates a series module with battery units and intermediate current collectors, where the first and second battery units have different energy densities, optimizing energy density and safety performance through careful selection and design of active materials and electrolytes.
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 connected in series within a single battery shell. This segmentation allows the system to achieve high energy density through series connection while maintaining safety through functional differentiation of units.
Solution Approach 2:
Different battery units are assigned different energy densities based on their positions and functions. The first battery units have higher energy density for energy storage, while the second battery units have lower energy density for safety and thermal stability. This local quality differentiation resolves the contradiction between overall energy density and thermal safety.
2Power
If multiple secondary batteries are connected in series to meet increasing power density demands, then the power density is improved, but the mechanical safety requirements become more stringent
Solution Approach 1:
The battery system segments power delivery function across multiple series-connected units, allowing high power density through series architecture while distributing mechanical stress and safety requirements across differentiated unit types.
Solution Approach 2:
Second battery units with lower energy density are strategically positioned to provide mechanical safety buffer zones, while first battery units provide power density. This local quality assignment satisfies both power density and mechanical safety requirements.
3Use of energy by moving object
If battery units with high energy density are used to achieve high overall 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 densities to different battery units based on their functional roles. First battery units use high energy density materials for energy storage, while second battery units use lower energy density materials for thermal stability, resolving the contradiction between overall energy density and thermal stability.
Solution Approach 2:
Second battery units with lower energy density act as intermediary safety elements between high energy density first battery units, providing thermal buffering and preventing thermal runaway propagation while allowing the system to maintain high overall energy density.
Data Source
AI summary
This application provides an internal series battery, including a series module including three or more battery units, each including a positive active material layer, a solid electrolyte layer and a negative active material layer stacked, and intermediate current collectors, each disposed between the corresponding two adjacent battery units connected in series therethrough; a positive current collector located at one end of the series module and electrically connected to the positive active material layer of the battery unit at the end; and a negative current collector located at the other end of the series module and 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 that have an energy density the same as and different from any one of the battery units at the two ends of the series module respectively.