Solid-State Battery Anode Layout to Prevent Internal Short Circuits
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Solution Overview
Problem
In all solid state batteries, the volume change of anode active materials during charge and discharge can lead to internal short circuits due to the mismatch in hardness between inorganic solid electrolytes and polymer electrolytes, causing deformation and contact issues between layers.
Innovation Solution
The battery design includes a cathode layer and a solid electrolyte layer with inorganic solid electrolytes, and an anode layer with a polymer electrolyte, where the anode layer has a smaller area than the solid electrolyte and cathode layers, preventing internal short circuits by maintaining a stable interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inorganic solid electrolyte is used in the cathode layer or solid electrolyte layer, then ion conductivity is improved, but the hardness mismatch causes deformation and internal short circuits
Solution Approach 1:
The patent applies local quality by making the anode layer smaller in area than the solid electrolyte layer and cathode layer, creating a localized configuration where the soft anode layer is surrounded by harder layers. This local structural arrangement prevents the soft anode layer from deforming during pressing while maintaining good interface contact, thus resolving the contradiction between ion conductivity and prevention of internal short circuits.
2Stability of the object's composition
If a polymer electrolyte is used in the anode layer, then the bonding state of the interface is maintained during expansion and contraction, but the ion conductivity is lower than inorganic solid electrolyte
Solution Approach 1:
The patent uses local quality by confining the polymer electrolyte to only the anode layer while using inorganic solid electrolyte in the solid electrolyte layer and/or cathode layer. This localized application allows the soft polymer electrolyte to accommodate volume changes in the anode active material, while the harder inorganic solid electrolyte provides high ion conductivity in other layers, thus resolving the contradiction between interface stability and ion conductivity.
3Area of stationary object
If the anode layer has the same area as solid electrolyte layer and cathode layer, then full contact is achieved, but deformation occurs during pressing causing internal short circuits
Solution Approach 1:
The patent applies asymmetry by making the anode layer smaller in area than the solid electrolyte layer and cathode layer, creating an asymmetric structure where the anode layer is surrounded by larger layers. This asymmetric design ensures that the softer anode layer does not deform during pressing operations, while still maintaining adequate contact area for electrical connection, thus preventing internal short circuits.
Data Source
AI summary
A main object of the present disclosure is to provide an all solid state battery in which occurrence of internal short circuit is inhibited. The present disclosure achieves the object by providing an all solid state battery including, in an order along with a thickness direction, a cathode layer, a solid electrolyte layer and an anode layer; wherein at least one of the cathode layer and the solid electrolyte layer contains an inorganic solid electrolyte; the anode layer contains a polymer electrolyte; and, in a plan view along with the thickness direction of the all solid state battery, an area of the anode layer is smaller than an area of the solid electrolyte layer and an area of the cathode layer.