Solid-State Battery Anode Granules for Si Crack Durability
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Solution Overview
Problem
The volume change of Si-based active materials during charge and discharge in all solid state batteries leads to cracks in the anode layer, disrupting ion and electron conducting paths and reducing capacity durability over time.
Innovation Solution
Incorporating a granulated body of Si-based active material and a molten salt with a melting point between 30°C and 120°C into the anode layer, which acts as a cushion in the solid state to inhibit crack formation and repairs cracks in the liquid state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If Si-based active material is used in the anode layer, then energy density is improved, but crack is easily generated in the anode layer when charge and discharge are repeated
Solution Approach 1:
The patent changes the physical state parameter of the molten salt from liquid to solid by controlling the temperature to be lower than its melting point. This parameter change allows the molten salt to exist in a solid state that can mechanically support and protect the Si-based active material during volume changes, while still maintaining its ion conductivity properties
Solution Approach 2:
The patent introduces molten salt as an intermediary substance between the Si-based active material particles. This intermediary fills the voids and spaces between particles, acting as a buffer that absorbs and distributes the mechanical stress generated during Si expansion and contraction, thereby preventing crack formation in the anode layer
2Duration of action of moving object
If Si-based active material undergoes volume change during charge and discharge, then ion conducting path and electron conducting path are cut off, but capacity durability degrades over time
Solution Approach 1:
The patent applies beforehand cushioning by pre-filling the spaces between Si-based active material particles with molten salt before the battery operates. This pre-positioned molten salt acts as a cushion that is already in place to absorb and distribute mechanical stress during subsequent charge and discharge cycles, preventing crack formation that would otherwise occur due to Si volume changes
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 battery maintains capacity durability by preventing crack formation and repairing cracks through the use of a molten salt that transitions between solid and liquid states, enhancing the battery's performance.
Implementation Method 1
a molten salt, which is in a solid state at 25° C.
Implementation Method 2
the molten salt that transitions between solid and liquid states
Data Source
AI summary
A main object of the present disclosure is to provide an all solid state battery with capacity durability. The present disclosure achieves the object by providing an all solid state battery including a cathode layer, an anode layer, and a solid electrolyte layer arranged between the cathode layer and the anode layer, wherein the anode layer contains a granulated body including a Si-based active material and a molten salt, which is in a solid state at 25° C.