Cylindrical Cell Winding Core for Uniform Pressure Distribution
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Solution Overview
Problem
Existing electrochemical energy storage cells with spiral-winding composite bodies face issues with local irregularities in the spiral structure, leading to uneven pressure distributions, mechanical stress, and potential ion exchange hindrances or lithium plating.
Innovation Solution
The energy storage cell features a hollow cylindrical winding composite body with a spiral structure, where the wrap core has local deviations from a cylindrical or hollow cylindrical shape in specific areas to compensate for irregularities in the spiral structure, thereby ensuring even pressure distribution and preventing mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a perfect cylindrical winding core is used, then the manufacturing precision is improved, but local irregularities in the spiral structure cause uneven pressure distribution and mechanical stress
Solution Approach 1:
The winding core is designed with local deviations from a perfect cylindrical shape at specific positions. These local shape variations allow the core to compensate for irregularities in the spiral structure of the wound composite body, ensuring uniform pressure distribution in critical areas while maintaining overall cylindrical form.
Solution Approach 2:
The winding core is pre-formed with specific shape deviations before the winding process. These pre-planned geometric variations are positioned to anticipate and compensate for irregularities that will occur during spiral winding, such as at the inner end where winding starts or where thickness changes occur.
2Strength
If the spiral structure is made perfectly regular, then the mechanical stress is reduced, but it is difficult to compensate for inherent winding irregularities
Solution Approach 1:
Rather than making the entire winding core complex, only specific local regions are designed with shape deviations. The core remains simple and cylindrical in most areas, with targeted geometric variations only where needed to compensate for known irregularity locations in the spiral structure.
3Reliability
If the winding core compensates for all irregularities, then the pressure distribution is improved, but the device complexity increases
Solution Approach 1:
The winding core implements compensation only at specific critical locations where irregularities occur, such as the inner end of the spiral or areas with thickness changes. The core maintains a simple cylindrical geometry in all other regions, avoiding unnecessary complexity while achieving pressure uniformity where it matters most.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An electrochemical energy storage cell (100) has the following features: a. It has a cylindrical housing enclosing an interior space, with a top and a bottom surface and an intermediate, circumferential housing shell (50; 70), b. the housing shell (50; 70) has an inner housing shell surface that bounds the interior space to the outside, c. a hollow cylindrical wound composite body (60) is arranged in the interior space, which has a spiral structure consisting of at least two electrode strips wound spirally around a winding axis and at least one separator strip arranged between the electrode strips, d. the electrode strips each comprise a ribbon-shaped current collector with an active material coating on both sides, e. the hollow cylindrical wound composite body comprises two end faces, a circumferential outer composite body shell surface and a circumferential inner composite body shell surface, f.The inner surface of the composite body defines an axially oriented cavity in the center of the wound composite body (60). A winding core (10; 20; 30) with a substantially cylindrical or hollow cylindrical shape is arranged in this axially oriented cavity. The winding core has an outer circumferential surface that is in contact with the inner surface of the composite body. It is proposed that the winding core (10; 20; 30) has a local deviation (11; 21; 31) from the cylindrical or hollow cylindrical shape in at least one region of its outer circumferential surface.