All-solid-state battery short circuit inspection using thermal expansion matched restraint jig
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing short circuit inspection methods for all-solid-state batteries are ineffective due to charge reactions occurring when applying high voltage, making it difficult to accurately determine the presence of short circuits, and the use of restraint jigs with mismatched thermal expansion coefficients leads to weakened force and reduced detection sensitivity.
Innovation Solution
A method involving a restraint jig with thermal expansion coefficients matching or exceeding those of the battery components, allowing for stable restraint and accurate detection of short circuits by cooling the battery assembly and applying voltage, and a kit for accommodating the jig with a refrigerant to maintain a stable cooled state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high voltage is applied to the all-solid-state battery assembly for short circuit inspection, then the inspection can be performed, but charge reaction occurs and functions as a battery making short circuit detection inaccurate
Solution Approach 1:
The patent applies a voltage between 1 V and 100 V (preferably 5 V to 50 V) instead of high voltage, which suppresses charge reactions while enabling sufficient current measurement for short circuit detection. This parameter change resolves the contradiction by finding an optimal voltage range that avoids harmful charge reactions while maintaining detection capability.
2Measurement precision
If the all-solid-state battery assembly is cooled to increase resistance for inspection, then detection sensitivity improves, but the assembly shrinks and becomes thinner weakening the restraint jig force
Solution Approach 1:
The patent selects restraint jig materials (bolts and nuts) with thermal expansion coefficients equal to or greater than the current collectors (α2 ≥ α1), ensuring that during cooling the restraint jig contracts less than or equal to the battery assembly. This maintains stable contact pressure and restraint force even at low temperatures, resolving the contradiction between detection sensitivity and restraint force.
3Force
If the thermal expansion coefficient of the restraint jig is less than the current collector, then the restraint jig contracts more upon cooling, but the detection sensitivity is lowered due to weakened force
Solution Approach 1:
The patent establishes the relationship α2 ≥ α1 for thermal expansion coefficients, ensuring the restraint jig contracts less than or equal to the current collector during cooling. This prevents excessive contraction that would weaken restraint force, thereby maintaining both sufficient force and detection sensitivity.
4Stability of the object's composition
If the all-solid-state battery assembly is restrained tightly for stable inspection, then measurement stability improves, but the assembly cannot be cooled effectively reducing detection accuracy
Solution Approach 1:
By matching thermal expansion coefficients (α2 ≥ α1), the restraint jig maintains stable contact pressure during cooling without excessive tightening or loosening. This allows effective cooling while preserving measurement stability, resolving the contradiction between these two requirements.
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
Enables high-accuracy short circuit inspection in all-solid-state batteries by maintaining stable force and sensitivity, even in low-temperature environments, allowing detection of finer conductive foreign matters and improving overall inspection reliability.
Implementation Method 1
when a smallest thermal expansion coefficient among the thermal expansion coefficient of the positive electrode current collector and the thermal expansion coefficient of the negative electrode current collector of the all-solid-state battery assembly is denoted by α1, the thermal expansion coefficients of the bolt and the nut are each equal to or greater than α1
Implementation Method 2
a resistance increase step of increasing the resistance of the all-solid-state battery assembly by cooling the restrained all-solid-state battery assembly
Data Source
AI summary
According to one aspect of the present invention, a short circuit inspection method for an all solid battery assembly is provided which includes: a step of preparing an all-solid-state battery assembly; a step of preparing a restraint jig including a pair of restraint plates sandwiching the all-solid-state battery assembly in the thickness direction, and a restraint member including a bolt and a nut, wherein where a smallest thermal expansion coefficient among the thermal expansion coefficient of the positive electrode current collector and the thermal expansion coefficient of the negative electrode current collector of the all-solid-state battery assembly is denoted by α1, the thermal expansion coefficients of the bolt and the nut are each equal to or greater than α1; a step of restraining the all-solid-state battery assembly; a step of increasing the resistance of the all-solid-state battery assembly by cooling; a step of applying a voltage to the all-solid-state battery assembly and measuring a current; and a step of determining whether or not a short circuit has occurred in the all-solid-state battery assembly on the basis of the measured current value.