All Solid State Battery Initial Charging Voltage Control
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Solution Overview
Problem
All solid state batteries face a challenge in improving capacity durability while suppressing the increase of initial resistance, as high charging voltages deteriorate cathode active materials and lead to increased resistance, while low voltages fail to enhance durability.
Innovation Solution
A method involving an all solid state battery with a cathode, solid electrolyte, and anode layers, where the anode layer includes metal particles capable of alloying with Li and having multiple crystal orientations, charged to a voltage between 4.35 V and 4.55 V, utilizing a sulfide solid electrolyte to achieve both improved durability and reduced resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the all solid state battery is charged to a high voltage (higher than normal use voltage) in the initial charging step to improve capacity durability, then the amorphization of the alloy-based anode active material is facilitated, but the cathode active material is easily deteriorated and the initial resistance is increased
Solution Approach 1:
The patent applies parameter changes by precisely controlling the charging voltage within a specific range (4.35V to 4.55V) during initial charging. This voltage parameter optimization enables sufficient amorphization of the anode active material to improve capacity durability, while preventing excessive voltage that would cause cathode material deterioration and increased initial resistance. The controlled voltage parameter resolves the contradiction between durability improvement and resistance control.
2Reliability
If the charging voltage is kept low to suppress the increase of initial resistance, then the cathode active material is protected from deterioration, but the capacity durability cannot be improved
Solution Approach 1:
The patent applies preliminary action by performing a specific initial charging step before normal use, where the battery is charged to a controlled high voltage (4.35V-4.55V) to pre-induce amorphization of the anode active material. This preliminary high-voltage charging prepares the anode structure in advance to achieve good capacity durability, while the voltage is controlled to avoid excessive cathode deterioration. After this preliminary action, normal charging operates at lower voltages to maintain low initial resistance.
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 effectively enhances capacity durability and suppresses the increase of initial resistance by optimizing the amorphization rate of the anode active material, maintaining battery performance without excessive resistance.
Implementation Method 1
the capacity durability is improved by charging the all solid state battery to a voltage higher than the voltage at normal use, in the initial charging step so as to facilitate the amorphization of the alloy-based anode active material
Data Source
AI summary
A main object of the present disclosure is to provide a method for producing an all solid state battery capable of satisfying both of improving capacity durability and suppressing the increase of an initial resistance. The above object is achieved by providing a method for producing an all solid state battery, the method comprising: a preparing step of preparing an all solid state battery including a cathode layer, a solid electrolyte layer, and an anode layer, in this order; and an initial charging step of initially charging the all solid state battery, wherein the anode layer includes a metal particle capable of being alloyed with Li, and having two kinds or more of crystal orientation in one particle, as an anode active material, and in the initial charging step, the all solid state battery is charged to a battery voltage of 4.35 V or more and 4.55 V or less.