Blended Graphite Anode for Solid-State Battery SEI Management
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Solution Overview
Problem
Solid-state batteries face inefficiencies in charge and discharge cycles due to excessive Solid Electrolyte Interphase (SEI) buildup, which reduces battery capacity and increases cell resistance, especially under high-temperature conditions.
Innovation Solution
A solid-state battery system with a graphite anode comprising a blend of relatively high and low specific surface area graphite particles, along with a gel electrolyte and various solid electrolyte materials, is designed to minimize SEI formation by optimizing the interfacial contact area and preventing excessive SEI buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If graphite anode uses high specific surface area particles to improve low-temperature performance, then low-temperature performance is improved, but SEI buildup increases excessively under high-temperature conditions
Solution Approach 1:
The patent applies local quality by creating a spatial distribution of different graphite particle sizes within the anode structure. Small graphite particles (high specific surface area) are positioned in regions where low-temperature performance is critical, while large graphite particles (low specific surface area) are positioned in regions where high-temperature stability is needed. This local differentiation allows the anode to exhibit both low-temperature reactivity and high-temperature stability simultaneously, preventing excessive SEI buildup while maintaining cold-weather performance.
2Object-generated harmful factors
If graphite anode uses low specific surface area particles to reduce SEI buildup, then SEI buildup is reduced, but low-temperature performance deteriorates
Solution Approach 1:
The patent employs composite materials by combining graphite particles of different sizes (and thus different specific surface areas) into a single anode structure. This composite approach allows the system to leverage the advantages of both small particles (high surface area for low-temperature performance) and large particles (low surface area for reduced SEI buildup). The composite graphite anode effectively integrates multiple material characteristics to resolve the contradiction between low-temperature performance and SEI management.
3Quantity of substance
If solid-state battery operates under high-temperature conditions, then energy density is improved, but cell resistance increases due to excessive SEI buildup
Solution Approach 1:
The patent applies parameter changes by modifying the physical parameters of the graphite anode, specifically the particle size distribution and specific surface area characteristics. By changing these parameters to include a blend of particle sizes rather than a uniform size, the anode's interaction with the electrolyte is optimized. This parameter modification allows the battery to maintain low cell resistance during high-temperature operation while preserving energy density, effectively decoupling the previously coupled trade-off between these two parameters.
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 blended graphite anode configuration enhances low-temperature performance, inhibits excessive SEI growth, and decelerates cell resistance increase during high-temperature cycling, thereby improving battery capacity retention and efficiency.
Implementation Method 1
The solid electrolyte layer or film is disposed between the graphite anode and the cathode and is operable to provide lithium-ion conduction paths between the graphite anode and the cathode
Implementation Method 2
the battery cell further includes a gel electrolyte which is operable to build up favorable lithium-ion conduction paths between solid-solid contacts in the graphite anode
Data Source
AI summary
A solid-state battery system including a graphite anode is provided. The system includes a battery cell. The battery cell includes the graphite anode, a cathode, and a solid electrolyte layer. The graphite anode includes a plurality of graphite particles, wherein the plurality of graphite particles includes a first portion of the plurality of graphite particles including a plurality of relatively high specific surface area graphite particles and a second portion of the plurality of graphite particles including a plurality of relatively low specific surface area graphite particles. The solid electrolyte layer is disposed between the graphite anode and the cathode and is operable to provide lithium-ion conduction path between the graphite anode and the cathode.