Lithium-Ion Battery Thickness Ratio for Electrolyte Balance
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Solution Overview
Problem
Existing lithium ion secondary batteries face challenges in designing an appropriate amount of electrolytic solution, leading to electrolytic solution accumulation or depletion, which affects battery lifetime.
Innovation Solution
The battery design ensures an appropriate amount of electrolytic solution by controlling the thickness ratio of the battery to the power generating element, maintaining it between 1.05 to 1.15 times, thereby managing electrolyte absorption and preventing non-uniform charge/discharge reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the amount of electrolytic solution is increased, then the battery can maintain operation longer without depletion, but electrolytic solution accumulation occurs between electrodes and separator causing non-uniform charge/discharge reactions
Solution Approach 1:
The invention controls the amount of electrolytic solution by adjusting the thickness of the package and power generating elements, maintaining a specific thickness ratio (0.95 ≤ thickness ratio ≤ 1.05) to prevent both accumulation and depletion, thereby resolving the contradiction between operation duration and charge/discharge uniformity
2Reliability
If the amount of electrolytic solution is decreased, then electrolytic solution accumulation is avoided, but the electrolytic solution is depleted more easily reducing battery lifetime
Solution Approach 1:
The invention establishes a precise thickness ratio range (0.95 ≤ thickness ratio ≤ 1.05) between the package and power generating element to optimize electrolytic solution quantity, preventing both depletion and accumulation, thereby simultaneously ensuring battery lifetime and charge/discharge uniformity
3Quantity of substance
If electrolytic solution accumulation occurs between power generating elements and package, then more electrolytic solution is retained, but non-uniform charge/discharge reactions occur reducing battery lifetime
Solution Approach 1:
The invention controls the thickness ratio (0.95 ≤ thickness ratio ≤ 1.05) to precisely regulate electrolytic solution quantity, preventing accumulation between power generating elements and package, thereby ensuring uniform charge/discharge reactions and extending battery lifetime
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 results in a lithium ion secondary battery with a longer lifetime and uniform thickness, minimizing electrolyte accumulation and depletion, thus enhancing cycle characteristics.
Implementation Method 1
If the amount of electrolytic solution is too much, an electrolytic solution accumulation may be created between the positive electrode or negative electrode and the separator, or between the power generating elements and the package
Data Source
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Figure 3
AI summary
Provided is a lithium ion secondary battery which is provided with an appropriate amount of electrolytic solution and which has a long lifetime. The lithium ion secondary battery (1) is provided with: a power generating element (10) including a positive electrode (12) and a negative electrode (11) which are laminated via a separator (13); an electrolytic solution; and a package (30) in which the power generating element and the electrolytic solution are disposed. A thickness obtained by subtracting a thickness of the package (30) from a thickness of the lithium ion secondary battery (1) is not less than 1.05 times and not more than 1.15 times a thickness of the power generating element (10) in a state in which the electrolytic solution is not included.