Battery Case Pre-Deformation for Secondary Battery Size Uniformity
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Solution Overview
Problem
Existing secondary battery manufacturing techniques struggle to effectively suppress size variations in secondary batteries, limiting the range of absorbable size differences and impacting battery performance and consistency.
Innovation Solution
A manufacturing method that involves a battery case deformation step where gas is injected into the battery case to expand the first side wall, forming an expansion surface with a high expansion area that exceeds the elastic range, allowing for plastic deformation and subsequent suppression of size variations during and after the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a spacer is used to absorb size variations of battery cells, then the accumulation of size errors can be managed, but the range of absorbable size variation is limited
Solution Approach 1:
The battery case is pre-deformed during manufacturing to have an expanded state with larger internal volume. This preliminary expansion allows the case to accommodate electrode bodies with size variations without requiring spacers, as the extra volume provides tolerance for dimensional differences in battery cells.
Solution Approach 2:
The internal volume of the battery case is changed by controlling the expansion degree during case formation. By adjusting expansion parameters (such as expansion pressure, temperature, or duration), the case can be tailored to have different internal volumes that match the specific size variations of electrode bodies, thereby increasing the range of absorbable size variations.
2Manufacturing precision
If the battery case is deformed by gas injection to form an expansion surface, then plastic deformation can be achieved to suppress size variations, but the process complexity increases
Solution Approach 1:
Gas is injected into the battery case to generate internal pressure that causes the case material to expand and deform. This pneumatic approach is simpler than mechanical deformation methods, as it uses fluid pressure to achieve uniform expansion across the case surface without requiring complex mechanical tooling or multiple deformation steps.
Solution Approach 2:
The expansion surface is formed with a specific geometric configuration where the top part (having the largest protruding amount) and high expansion area (where protruding amount is ≥1/2 of maximum expansion width) are controlled to occupy at least 1/3 of the total expansion surface area. This local quality control ensures that the deformation is concentrated in critical areas that most effectively suppress size variations while maintaining overall case integrity.
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 method effectively inhibits size variations in secondary batteries by causing plastic deformation of the battery case, enhancing manufacturing efficiency and improving battery pack performance by ensuring uniformity and consistency among multiple batteries.
Implementation Method 1
a case deforming step for injecting a gas via the electrolytic solution liquid injection hole to an inside of the battery case having been assembled so as to deform the battery case
Implementation Method 2
The expansion surface includes a top part which is a portion having the largest protruding amount in the first direction, and a reference part which is a portion having the smallest protruding amount. Here, the protruding amount from the reference part to the top part in the first direction is defined as a maximum expansion width H, an area where the protruding amount from the reference part is equal to or more than 1⁄2 of the maximum expansion width H is defined as a high expansion area. The case deforming step is controlled to make an area size of the high expansion area in a front view be equal to or more than 1⁄3 of a total area size of the expansion surface.
Data Source
AI summary
A herein disclosed manufacturing method includes a battery case assembling step, a case deforming step, a liquid injecting step, and a sealing step. Here, the case deforming step is controlled to make an area size of the high expansion area in a front view be equal to or more than ⅓ of a total area size of an expansion surface on a first side wall. By doing this, a whole plastic deformation due to an expansion from an inside is caused on the first side wall, and thus it is possible to suppress a size variation in the secondary batteries after the manufacture.