Solid-State Battery Negative Electrode Tuning for Capacity Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
All-solid-state batteries face challenges in maintaining discharge capacity after storage, especially at high temperatures, due to increased resistance in lithium titanium oxide negative electrodes, which affects charging capacity and recovered capacity.
Innovation Solution
The all-solid-state battery system incorporates a negative electrode with a lithium titanium oxide active material, controlling the negative electrode discharge utilization rate to 134 mAh/g or less, and using a sulfide-based solid electrolyte to prevent resistance increase and maintain capacity, by adjusting the amount and type of active materials and electrolytes, and employing a conductive aid like graphene to enhance conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the negative electrode discharge utilization rate is increased to improve battery capacity, then the initial capacity increases, but the resistance of lithium titanium oxide increases after storage at high temperatures, reducing recovered capacity
Solution Approach 1:
The patent applies parameter changes by optimizing the negative electrode discharge utilization rate to a specific range (100-130 mAh/g). This parameter optimization balances the initial battery capacity with the resistance stability of lithium titanium oxide after high-temperature storage, ensuring both high initial capacity and maintained recovered capacity without excessive resistance increase.
2Quantity of substance
If the amount of lithium titanium oxide in the negative electrode is increased to improve capacity, then the battery capacity increases, but the resistance increase after storage becomes more severe
Solution Approach 1:
The patent changes the parameter of negative electrode discharge utilization rate to an optimal range (100-130 mAh/g), which controls the amount of lithium titanium oxide relative to other components. This parameter optimization allows sufficient lithium titanium oxide for high capacity while preventing excessive resistance increase after storage.
Solution Approach 2:
The patent uses composite materials by combining lithium titanium oxide with other negative electrode materials and conductive aids in specific proportions. This composite approach distributes the functional requirements, allowing lithium titanium oxide to provide capacity while other materials help maintain conductivity and reduce resistance increase during storage.
3Use of energy by moving object
If the battery is designed for high initial capacity to meet energy density requirements, then the energy density increases, but the discharge capacity after storage deteriorates
Solution Approach 1:
The patent optimizes the negative electrode discharge utilization rate parameter to balance energy density and storage performance. By setting this parameter in the range of 100-130 mAh/g, the battery achieves high energy density through sufficient capacity while maintaining stable discharge capacity after storage by controlling resistance increase.
Solution Approach 2:
The patent applies beforehand cushioning by pre-optimizing the negative electrode composition and utilization rate to prevent excessive resistance increase before storage occurs. This proactive design ensures that when high-temperature storage happens, the resistance increase is already mitigated, preserving discharge capacity after storage.
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 approach inhibits resistance increase in lithium titanium oxide, maintaining high discharge capacity and recovered capacity even after storage at high temperatures, ensuring reliable battery performance.
Implementation Method 1
a solid electrolyte layer formed between the positive electrode layer and the negative electrode layer
Implementation Method 2
the negative-electrode active material contains a lithium titanium oxide
Implementation Method 3
employing a conductive aid like graphene to enhance conductivity
Data Source
AI summary
An all-solid-state battery system according to this application includes an all-solid-state battery and a charging apparatus, in which the all-solid-state battery includes a positive electrode, a negative electrode, and a solid electrolyte layer located between the positive electrode and the negative electrode, the negative electrode contains a negative-electrode active material and a solid electrolyte, the negative-electrode active material contains a lithium titanium oxide, and a negative electrode discharge utilization rate X calculated using the following equation is 134 mAh/g or less. The negative electrode discharge utilization rate X=battery capacity Q (mAh)/mass of the negative-electrode active material in the negative electrode (g), where the battery capacity Q is a discharge capacity (mAh) obtained when the battery is charged with a constant current at 0.2 C to the upper limit charging voltage, charged with a constant voltage to 0.002 C, and discharged at 0.002 C to 1 V.