Monopolar Solid-State Battery Stack for High-Voltage Series Integration
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Solution Overview
Problem
Existing all-solid-state battery stacks with bipolar structures face issues such as strain-induced cracking, increased volume and mass due to overlaid current collector layers, and potential internal short-circuiting, limiting their voltage and energy density.
Innovation Solution
An all-solid-state battery stack design featuring monopolar battery units stacked via insulator layers, with integrated current collector layers and insulator layers to prevent short-circuiting and reduce volume, using a structure where each monopolar unit has a first and second current collector layer, active material layers, and solid electrolyte layers, connected in series.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a bipolar structure with a single current collector layer is used, then high voltage is achieved through series connection, but the current collector layer experiences strain and cracking due to differential stretchability of electrode layers
Solution Approach 1:
The patent divides the current collector function into separate positive electrode collector layers and negative electrode collector layers for each structural unit cell. This segmentation eliminates the strain issue by providing dedicated collector layers for each electrode type, preventing the cracking that occurs when a single current collector layer must accommodate differential stretchability of both positive and negative electrode active material layers.
2Power
If multiple structural unit cells are stacked with positive and negative electrode collector layers laid against each other, then series connection is achieved, but volume and mass increase due to mutually overlaid current collector layers
Solution Approach 1:
The patent merges the positive electrode collector layer and negative electrode collector layer into a single integrated current collector layer for each structural unit cell. This merging eliminates the need for mutually overlaid collector layers when stacking multiple unit cells, thereby reducing the overall volume and mass of the battery stack while maintaining the series connection capability through the monopolar structure.
3Device complexity
If a single current collector layer is used for both positive and negative electrodes, then device complexity is reduced, but material selection is limited
Solution Approach 1:
The patent segments the current collector into separate positive electrode collector layers and negative electrode collector layers, allowing each to be optimized for its specific electrode type. This segmentation enables independent material selection for each collector layer, providing greater versatility in material choice while maintaining structural simplicity through the integrated monopolar design.
4Device complexity
If current collector layers are stacked without additional insulation, then device complexity is minimized, but internal short circuiting occurs when layers fracture
Solution Approach 1:
The patent introduces insulator layers as intermediary elements between adjacent monopolar battery units. These insulator layers prevent direct contact between positive and negative electrode collector layers from different units, eliminating the risk of internal short circuiting that would occur if fractured current collector layers came into direct contact, while adding minimal structural complexity.
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.