Prismatic Solid-State Cell Assembly With Internal Compression
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Solution Overview
Problem
Conventional prismatic cell assemblies with solid-state electrolytes face challenges due to volume changes in cathodes, leading to lower energy density and potential safety issues from gaps that can fill beyond design thickness, affecting electrochemical performance.
Innovation Solution
A prismatic cell assembly with a pre-deformed elastic body that provides internal compression to the solid electrolyte and electrodes, eliminating gaps and enhancing contact resistance, formed by welding a first and second plate with elastic bodies between the internal walls and stacks of sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a gap is reserved between the electrode/electrolyte sheets and the inner wall of the case to accommodate volume change, then the cathode volume change is accommodated, but the energy density is reduced due to the existence of the gap
Solution Approach 1:
A pre-compressed elastic body is introduced as an intermediary element between the electrode/electrolyte sheets and the housing wall. This elastic body serves as a mediator that accommodates cathode volume expansion while maintaining continuous contact pressure, thereby preventing gap formation and preserving high energy density without compromising cathode stability.
Solution Approach 2:
The elastic body is pre-compressed during assembly to a specific compression ratio, storing elastic potential energy. As the cathode expands during operation, the elastic body decompresses, maintaining contact pressure. This parameter change (compression ratio) allows the system to adapt to volume changes while eliminating gaps, thus resolving the contradiction between stability and energy density.
2Quantity of substance
If the gap is filled up under some circumstances, then the energy density is improved, but safety issues arise due to exceeding the design thickness range
Solution Approach 1:
The elastic body provides a dynamic solution that adapts to cathode volume changes during operation. Unlike a rigid filler that would exceed design thickness when the cathode expands, the elastic body compresses and decompresses dynamically, maintaining optimal contact pressure without exceeding the housing's design thickness limits, thus ensuring both high energy density and safety.
Solution Approach 2:
The elastic body is pre-compressed during assembly to create a cushioning effect. This pre-compression stores elastic energy that is released as the cathode expands, preventing the need for additional space and avoiding safety issues related to exceeding design thickness, while still accommodating volume changes safely.
3Ease of manufacture
If conventional assembly methods are used for solid-state batteries, then the manufacturing process is simple, but the electrochemical performance is far from ideal due to contact resistance
Solution Approach 1:
The elastic body is pre-compressed during the assembly process itself, before the battery begins operation. This preliminary action of compression ensures that the electrode/electrolyte sheets are held together with optimal contact pressure from the start, eliminating contact resistance issues without requiring complex post-assembly adjustments or additional manufacturing steps, thus maintaining manufacturing simplicity while improving electrochemical performance.
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 improves electrochemical performance and extends the lifetime of all-solid-state prismatic cells by maintaining consistent compression pressure without external forces, enhancing energy density and safety.
Implementation Method 1
a pre-deformed elastic body positioned within the housing (for example, placed between the internal wall of the housing and the top or bottom of one of the stacked sheets or sandwiched within the stacked sheets), wherein the pre-deformed elastic body exerts an internal compression on or among the stacks without the application of external forces on the housing post-manufacture of the prismatic cell assembly
Data Source
AI summary
Disclosed is a prismatic cell assembly, comprising a housing, a stacked sheets (or layers) comprising electrode and solid electrolyte, and a pre-deformed elastic body placed on the top or bottom of or sandwiched within the stacked sheets, wherein the compressed or deformed elastic body exerts an internal compression among the stacked sheets. In one embodiment, the housing is formed by welding a first plate and a second plate. In one embodiment, the cell assembly exhibits an improved electrochemical performance and longer lifetime.