Prismatic Solid-State Cell Stack With Compliant Pressure Layers
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Solution Overview
Problem
Solid-state batteries (SSBs) face challenges in achieving homogeneous cell stack pressure without reducing packaging efficiency, as they require high pressure for proper contact between layers and can expand significantly during charge-discharge cycles, making it difficult to maintain mechanical properties and efficient use of space in electrified vehicle batteries.
Innovation Solution
A solid-state battery prismatic cell stack design featuring a substantially rigid casing with narrow sides and broad faces, incorporating a compliant material between cells to accommodate up to 20% displacement and a potting material to maintain stack pressure, along with a battery management system to adjust operation based on state-of-charge and cell impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high cell stack pressure is applied to achieve proper contact between layers, then contact quality and cell morphology are improved, but packaging efficiency is reduced due to significant cell expansion during charge-discharge cycles
Solution Approach 1:
The patent applies a compliant material with specific mechanical properties (modulus of elasticity between 0.1-10 MPa) between cells to dynamically adjust and maintain contact pressure. This material allows cells to expand during charge-discharge cycles while maintaining sufficient contact pressure, thus preserving both contact quality and packaging efficiency through parameter optimization of the intercellular material
Solution Approach 2:
The compliant material acts as an intermediary element between adjacent cells, accommodating their relative displacement during operation. This mediator absorbs expansion forces and maintains homogeneous pressure distribution across cell interfaces, resolving the contradiction between maintaining contact quality and preserving packaging efficiency
2Adaptability or versatility
If significant cell expansion is accommodated during charge-discharge cycles, then cell breathing is allowed, but homogeneous cell stack pressure becomes difficult to achieve
Solution Approach 1:
The compliant material's elastic properties enable it to deform with cell expansion while maintaining contact pressure. By selecting materials with appropriate modulus of elasticity (0.1-10 MPa), the system adapts to cell volume changes during charge-discharge cycles while preserving homogeneous pressure distribution across the cell stack
3Strength
If more casing materials are used to maintain mechanical properties, then structural integrity is improved, but energy storage density is reduced
Solution Approach 1:
The patent replaces traditional rigid casing materials with thin, flexible compliant layers between cells. These thin films provide necessary mechanical support and pressure distribution without adding significant volume, thus maintaining structural integrity while maximizing energy storage density by minimizing non-active material
Solution Approach 2:
The system uses composite construction with a rigid outer casing combined with compliant intercellular materials. This composite approach distributes structural functions: the rigid casing provides overall protection while the compliant material layers provide local pressure management, reducing total material usage and increasing energy density
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 maintains suitable cell stack pressure while minimizing the use of casing materials, enhancing energy storage density and extending battery life by accommodating cell expansion and ensuring consistent performance across various states-of-charge.
Implementation Method 1
a compliant material being disposed may accommodate a displacement of a surface of the relatively broad opposing faces of the plurality of cells up to 20 percent
Data Source
AI summary
Subject matter herein relates to a solid-state battery (SSB) prismatic cell stack, an energy storage system that may utilize a SSB prismatic cell stack, and a method of manufacturing a SSB prismatic cell stack. In an embodiment, a SSB prismatic cell stack may include a substantially rigid casing including a top cover and relatively narrow opposing sides in relation to relatively broad opposing faces; a plurality of cells stacked within the substantially rigid casing, the plurality of cells having relatively broad opposing faces and relatively narrow opposing sides; a compliant material disposed between faces of adjacent cells of the plurality of cell to accommodate an increase of up to 20 percent displacement of a surface of the relatively broad opposing faces of the plurality of cells and a potting material to be placed proximate to one or more of the relatively narrow opposing sides of the plurality of cells.