Porous Support Layer in Bipolar Solid-State Batteries for Dendrite Control
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Solution Overview
Problem
Bipolar all-solid-state batteries face issues with lithium dendrite formation leading to solid electrolyte damage and short circuits, along with increased stress and internal pressure due to lithium deposition, which affects battery density, capacity, and lifespan.
Innovation Solution
Incorporating a porous support layer between unit cells to manage stress and prevent lithium dendrite contact, using either a first porous support layer between positive and negative electrodes or a second porous support layer as a separator, which adjusts thickness and porosity to maintain uniform pressure and prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a bipolar all-solid-state battery uses lithium to increase density and capacity, then energy density is improved, but lithium dendrites form causing solid electrolyte damage and short circuits
Solution Approach 1:
A porous support layer is introduced as an intermediary component between the solid electrolyte and the electrodes. This support layer physically blocks lithium dendrites from penetrating through the solid electrolyte, preventing short circuits while allowing the battery to maintain high energy density using lithium. The support layer acts as a mechanical barrier that mediates between the high-density lithium-based chemistry and the safety requirement of preventing dendrite-induced short circuits.
2Reliability
If a bipolar all-solid-state battery is pressed to reduce interfacial resistance, then contact between electrodes and solid electrolyte is improved, but stress increases causing solid electrolyte damage
Solution Approach 1:
The porous support layer is designed with a porous structure that can accommodate and distribute the stress generated during battery operation and pressing. The porosity allows the support layer to deform elastically under pressure, absorbing stress without transmitting it directly to the solid electrolyte, thereby preventing solid electrolyte damage while maintaining good interfacial contact between electrodes and electrolyte.
3Reliability
If the contact area between electrodes and solid electrolyte is increased, then interfacial resistance is reduced, but the battery volume increases
Solution Approach 1:
The porous support layer is designed as a thin film structure that provides extensive surface area for electrode-solid electrolyte contact without significantly increasing the overall battery volume. The thin film nature allows the support layer to maintain small thickness while its porous structure provides large surface area, enabling reduced interfacial resistance without substantial volume increase.
Data Source
AI summary
A bipolar all-solid-state battery including a porous support layer is provided. The bipolar all-solid-state battery comprises (a) two or more unit cells each including a positive electrode, a solid electrolyte, and a negative electrode being connected to each other in series and a first porous support layer provided at an interface therebetween; or (b) two or more unit cells each including a positive electrode, a solid electrolyte, and a second porous support layer being connected to each other in series.