Secondary Battery Electrodes Using Meltable Salt Crack Repair
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Solution Overview
Problem
Secondary batteries face performance degradation due to volume changes in active materials during charging and discharging, leading to cracks and increased resistance, especially when inorganic solid electrolytes are used in the electrodes.
Innovation Solution
Incorporating a granulated body with an inorganic solid electrolyte and an alkali metal-containing salt into the electrodes, where the alkali metal-containing salt is heated to its melting point to repair cracks and maintain low resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inorganic solid electrolyte is contained together with the active material in the positive electrode and the negative electrode, then the battery performance is improved, but cracks and gaps occur in the electrodes due to volume changes during charging and discharging
Solution Approach 1:
The patent changes the physical state parameter of the alkali metal-containing salt by heating it to its melting point, transforming it from solid to liquid state. This parameter change enables the salt to flow and fill cracks and gaps in the electrode, thereby maintaining electrode integrity while preserving battery performance
Solution Approach 2:
The patent utilizes the phase transition of the alkali metal-containing salt from solid to liquid state through heating. This phase transition is the core mechanism that enables the salt to repair cracks and gaps in the electrode structure, resolving the contradiction between maintaining battery performance and preventing electrode degradation
2Use of energy by moving object
If the volume of the active material changes as the battery is charged and discharged, then the electrochemical reaction is enabled, but cracks and gaps occur in the positive electrode and the negative electrode
Solution Approach 1:
The alkali metal-containing salt acts as an intermediary substance that mediates between the active material and the inorganic solid electrolyte. When heated to melting point, this intermediary flows into cracks and gaps caused by volume changes, maintaining structural strength while allowing the electrochemical reaction to proceed
Solution Approach 2:
By changing the temperature parameter of the alkali metal-containing salt to its melting point, the patent transforms its physical state from solid to liquid, enabling it to fill and repair structural defects in the electrode without interfering with the electrochemical reaction
3Stability of the object's composition
If heating is applied to the alkali metal-containing salt to repair cracks, then the electrode integrity is restored, but energy consumption increases
Solution Approach 1:
The heating process is applied periodically rather than continuously - only when cracks and gaps are detected in the electrode. This periodic action reduces energy consumption while still achieving the goal of restoring electrode integrity when needed
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 solution effectively repairs cracks and maintains low resistance in secondary batteries by liquefying the alkali metal-containing salt to fill gaps, thereby restoring ion and conductive pathways.
Implementation Method 1
the control device controls heating by the heating device such that a temperature of the alkali metal-containing salt is equal to or higher than a melting point of the alkali metal-containing salt
Implementation Method 2
a heating device... the control device controls heating by the heating device
Data Source
AI summary
A secondary battery system of the present disclosure includes a secondary battery and a heating device, wherein the secondary battery includes a positive electrode and a negative electrode, and one or both of the positive electrode and the negative electrode include an active material and a granulated body, the active material includes a material whose volume changes with charge and discharge of the secondary battery, the granulated body includes an inorganic solid electrolyte and an alkali metal-containing salt, and a target heated by the heating device includes the alkali metal-containing salt.