Solid-State Battery Resin Cradle for Separator Crack Prevention
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Solution Overview
Problem
Solid-state lithium-ion batteries in an anode overhang configuration often experience cracks in the solid-state separator around the edge of the cathode due to stress accumulation after pressure application, which can lead to short circuits.
Innovation Solution
A compacted solid-state battery cell design is implemented, featuring a separator-anode laminate with a solid resin cradle printed around the perimeter of the separator side, allowing the cathode to be placed inside and compressed with the separator, anode, and solid resin layers to form a battery cell, thereby distributing pressure more evenly and reducing stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure is applied to increase interlayer contact and conductivity, then battery performance is improved, but stress accumulation causes cracks in the separator
Solution Approach 1:
The anode is extended beyond the separator perimeter before assembly, creating an anode overhang configuration. This preliminary structural arrangement allows the anode to extend into regions where stress would otherwise concentrate on the separator edges, preventing crack formation during subsequent pressure application while maintaining good interlayer contact and conductivity for battery performance
Solution Approach 2:
The battery structure is designed with different functional zones: the central region has standard layer stacking for ionic conduction, while the peripheral region features anode overhang extending beyond the separator. This local differentiation allows stress to be distributed to the more compliant anode material in the overhang region rather than concentrating on the brittle separator edges, resolving the contradiction between pressure-induced performance improvement and separator integrity
2Reliability
If the cathode is compressed with the separator and anode, then interlayer contact is improved, but stress concentrates at the cathode edges causing separator cracks
Solution Approach 1:
The anode is pre-configured to extend beyond the separator perimeter, creating a stress-absorbing overhang structure before the cathode is assembled. This preliminary arrangement ensures that during compression, stress is distributed to the anode overhang rather than concentrating at the cathode edges and separator interface, preventing crack formation while maintaining effective interlayer contact
Solution Approach 2:
The anode overhang acts as an intermediary stress-absorbing element between the cathode and separator. During compression, the compliant anode material in the overhang region absorbs and distributes stress, preventing direct stress transfer to the separator edges and cathode perimeters, thereby eliminating stress concentration points that would cause cracks
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
The proposed design effectively mitigates crack formation in the separator by evenly distributing pressure and maintaining a gap between the compressed cathode and an uncompressed anode, thus enhancing the structural integrity and preventing short circuits in solid-state lithium-ion batteries.
Implementation Method 1
distributing pressure more evenly and reducing stress concentrations
Implementation Method 2
A modulus of elasticity of the solid resin layers may be within 10% of a modulus of elasticity of the cathode
Data Source
AI summary
A solid-state battery with a particular structure and methods for forming such are discussed. The solid-state battery comprises a compacted solid-state battery cell including a separator-anode laminate, a plurality of solid resin layers defining a cradle around and extending away from a perimeter of a separator side of the separator-anode laminate, and a cathode disposed within the cradle and in direct contact with the separator side such that adjacent exterior surfaces of the cradle and cathode are flush.