Solid-State Battery Anode Coating for Heat and Resistance Balance
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Solution Overview
Problem
The volume variation due to charge/discharge of Si-based active materials in all solid state batteries is large, leading to high heating values during short circuits, which can increase internal resistance and compromise battery performance.
Innovation Solution
An all solid state battery design that includes an anode active material layer with a Si-based active material and an anode current collector with a coating layer containing an oxide active material, such as lithium titanate, where the thickness ratio of the coating layer to the anode active material layer is between 3% and 13%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Si-based active material is used as anode active material, then capacity property is improved, but heating value increases during short circuit
Solution Approach 1:
A coating layer comprising oxide active material is introduced as an intermediary between the Si-based anode active material and the electrolyte. This coating layer acts as a mediator that suppresses harmful reactions and reduces heating value during short circuits, while maintaining the high capacity properties of the Si-based material.
Solution Approach 2:
The anode structure is designed as a composite system combining Si-based active material with a coating layer of oxide active material. This composite structure leverages the high capacity of Si while the oxide coating provides safety benefits by reducing heating value, achieving both performance and safety requirements.
2Object-generated harmful factors
If coating layer thickness is increased to decrease heating value, then safety is improved, but internal resistance increases
Solution Approach 1:
The thickness of the coating layer is precisely controlled within the range of 3% to 13% of the anode active material layer thickness. This parameter optimization ensures that the coating is thick enough to reduce heating value and improve safety, but thin enough to maintain low internal resistance and good battery performance.
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 effectively decreases the heating value while preventing an increase in internal resistance, thereby maintaining desired battery performance.
Implementation Method 1
the heating value tends to be high, when a short circuit occurs... effectively decreases the heating value
Data Source
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AI summary
A main object of the present disclosure is to provide an all solid state battery capable of decreasing the heating value while suppressing the internal resistance increase. The present disclosure achieves the object by providing an all solid state battery comprising an anode active material layer, and an anode current collector, and the anode active material layer includes an anode active material whose total volume expansion rate, due to charge, is 14% or more, the anode current collector includes a coating layer including an oxide active material, on a surface of the anode active material layer side, and a ratio of a thickness of the coating layer to a thickness of the anode active material layer is 3% or more and 13% or less.