Monopolar Solid-State Battery Stack Layout for High-Voltage Reliability
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Solution Overview
Problem
Existing all-solid-state battery stacks with bipolar structures face issues such as strain and cracking in current collector layers due to differences in stretchability between negative and positive electrode active material layers, and increased volume and mass from mutually overlaid current collector layers, leading to reduced energy density and potential internal short circuits.
Innovation Solution
The solution involves an all-solid-state battery stack with a plurality of monopolar battery units stacked via insulator layers, where each monopolar unit has a specific layered structure and the units are connected in series, minimizing strain on current collector layers and reducing the number of current collector layers to enhance energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a bipolar structure with direct layering of positive and negative electrode active material layers on current collector layers is employed, then high voltage can be achieved, but strain and cracking occur in the current collector layers due to differences in stretchability between electrode layers
Solution Approach 1:
The battery is divided into multiple structural unit cells, each containing a current collector layer sandwiched between two solid electrolyte layers. This segmentation isolates the current collector layers from direct contact with both positive and negative electrode active material layers simultaneously, preventing the stretchability mismatch from causing strain and cracking while maintaining the series connection for high voltage output.
Solution Approach 2:
Solid electrolyte layers are introduced as intermediary layers between the current collector layers and the electrode active material layers. These intermediary solid electrolyte layers accommodate the differences in stretchability without transmitting strain to the current collector layers, thereby preventing cracking while allowing the bipolar structure to function for high voltage generation.
2Power
If multiple structural unit cells are stacked with positive and negative electrode collector layers laid against each other, then a bipolar structure is formed, but the volume and mass increase due to mutually overlaid current collector layers, reducing energy density
Solution Approach 1:
Adjacent current collector layers from different structural unit cells are merged into a single integrated current collector layer. This merging eliminates the redundant overlaid current collector layers that would otherwise increase volume and mass, while still maintaining the series connection between multiple unit cells to achieve high voltage output.
Solution Approach 2:
The current collector layers serve multiple functions: they collect current from electrode active material layers and simultaneously act as structural separators between adjacent unit cells. This multi-functionality eliminates the need for separate overlaid current collector layers, reducing overall battery volume and mass while maintaining high voltage capability.
3Device complexity
If a single current collector layer is used for both positive and negative electrode collector layers, then device complexity is reduced, but the range of material selection is limited
Solution Approach 1:
The current collection function is segmented into separate positive electrode collector layers and negative electrode collector layers. This segmentation allows each current collector layer to be independently optimized for its specific electrode type, expanding material selection versatility while maintaining clear structural organization and avoiding excessive complexity.
4Ease of manufacture
If current collector layers are fractured during production or use, then internal short circuiting occurs due to direct contact between positive and negative electrode active material layers
Solution Approach 1:
Solid electrolyte layers are positioned beforehand to cushion and protect the current collector layers from fracture. These intermediary solid electrolyte layers act as a safety buffer that prevents direct contact between positive and negative electrode active material layers even if current collector layers fracture during production or use, thereby preventing internal short circuits.
Solution Approach 2:
Solid electrolyte layers serve as intermediary protective layers between the current collector layers and electrode active material layers. This intermediary structure provides an additional safety mechanism that prevents internal short circuits by maintaining physical separation even when current collector layers are compromised.
Data Source
AI summary
The invention provides an all-solid-state battery stack with high voltage. The all-solid-state battery stack of the disclosure has a plurality of monopolar battery units stacked together via insulator layers. The monopolar battery unit also has a first current collector layer, a first active material layer, a solid electrolyte layer, a second active material layer, a second current collector layer, a second active material layer, a solid electrolyte layer, a first active material layer and a first current collector layer, stacked in that order. The plurality of monopolar battery units are connected together in series.