All Solid State Battery Densification via Lithium Phosphate Additive
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Solution Overview
Problem
All solid state batteries using inorganic solid electrolytes face challenges with low ion conductivity and performance deterioration during charge-discharge cycles due to insufficient densification of the negative electrode, positive electrode, and solid electrolyte layers.
Innovation Solution
Incorporating a sintering additive like lithium phosphate (Li3PO4) into the layers to enhance densification, thereby improving ion conductivity and stability, with optimal ratios of additives that balance density and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic solid electrolyte is used to eliminate liquid leakage and improve heat resistance, then battery safety and temperature range are improved, but ion conductivity is insufficient and output performance deteriorates
Solution Approach 1:
The patent changes the physical state parameter of the electrolyte from liquid to solid, eliminating leakage risks and improving heat resistance. This parameter change enables the battery to operate safely across a wide temperature range while maintaining structural integrity.
Solution Approach 2:
The patent uses composite materials by combining inorganic solid electrolyte particles with organic binder materials to create a composite electrolyte layer. This composite structure maintains the safety advantages of solid electrolytes while improving ion conductivity through the organic component's contribution to ionic transport.
2Ease of manufacture
If solid electrolyte layer is formed without sufficient densification, then manufacturing simplicity is maintained, but ion conductivity remains low and battery performance deteriorates
Solution Approach 1:
The patent applies a densification process that changes the physical density parameter of the solid electrolyte layer. By increasing the density through controlled compression or sintering, the ion conductivity is significantly improved while maintaining manufacturing simplicity through a straightforward post-forming treatment step.
3Device complexity
If battery is assembled without proper densification of electrode and electrolyte layers, then assembly process simplicity is maintained, but battery performance deteriorates during charge-discharge cycles
Solution Approach 1:
The patent performs preliminary densification of the electrode and electrolyte layers before final battery assembly. This preliminary action ensures proper contact and structural integrity are established in advance, preventing performance deterioration during subsequent charge-discharge cycles while keeping the assembly process simple.
Solution Approach 2:
The patent applies densification treatment that changes the physical parameters of the electrode and electrolyte layers, improving their mechanical properties and interfacial contact. This parameter change enhances cycle stability by preventing delamination and maintaining electrical contact during repeated charging and discharging operations.
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 addition of lithium phosphate significantly increases ion conductivity and maintains battery performance over repeated charge-discharge cycles, ensuring high stability and durability of the battery.
Implementation Method 1
at least one of the solid electrolyte layer, the positive electrode layer, and the negative electrode layer was fired after an additive material capable of helping the densification was added
Data Source
AI summary
An all solid state battery having high output performance and a manufacturing method thereof are provided. The all solid state battery of the present invention comprises a negative electrode layer, a positive electrode layer, and a solid electrolyte layer having a lithium ion conductivity. At least one layer of the solid electrolyte, the positive electrode layer, and the negative electrode layer includes a lithium ion conductive crystal and AxByOz (A is one or more selected from the group consisting of Al, Ti, Li, Ge, and Si. B is one or more selected from the group consisting of P, N, and C, wherein 1≦X≦4, 1≦Y≦5, and 1≦Z≦7). The solid electrolyte material to which a preferable sintering additive is added in a predetermined ratio is densified by firing at relatively low temperature in the manufacturing process. The ion conductivity thereof is also high.