Secondary Battery Electrode Layout for Axial Expansion Buffering
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Solution Overview
Problem
The expansion of electrode assemblies in secondary batteries leads to combined expansion forces when batteries are arranged in series or parallel, requiring high structural strength connectors that increase the volume and reduce energy density and space utilization.
Innovation Solution
The design of a secondary battery unit where the electrode assembly expands primarily in the axial direction, with buffer gaps and strategically sized gaps between electrode layers to absorb expansion forces, reducing the need for high-strength connectors and enhancing energy density and space utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the connector volume is increased to restrain and offset the expansion force, then the structural strength is improved, but the energy density and space utilization are reduced
Solution Approach 1:
The patent redirects the expansion force direction from the thickness direction (Y-axis) to the axial direction (Z-axis) by changing the expansion direction of the electrode assembly. This dimensional change allows the expansion force to be released in a direction where it does not accumulate with other batteries, eliminating the need for high-strength connectors while maintaining structural integrity.
Solution Approach 2:
The patent converts the harmful expansion force into a beneficial direction by designing the electrode assembly to expand primarily in the axial direction. The buffer gaps are strategically positioned to absorb expansion forces in the thickness direction, transforming the potential harmful lateral expansion into controlled axial expansion that does not compromise structural strength or energy density.
2Strength
If the connector volume is increased to restrain and offset the expansion force, then the structural strength is improved, but the space utilization is reduced
Solution Approach 1:
The patent changes the expansion direction from the thickness direction to the axial direction, allowing batteries to be arranged more efficiently in space. The buffer gaps are positioned to absorb expansion in the thickness direction while the primary expansion occurs axially, reducing the space required for connectors and improving overall space utilization.
3Adaptability or versatility
If the expansion force is released in the arrangement direction of secondary batteries, then the electrode assembly expansion is accommodated, but the expansion forces combine to form a large resultant force
Solution Approach 1:
The patent changes the expansion direction from the arrangement direction (thickness direction) to the axial direction. Buffer gaps are positioned to accommodate expansion in the thickness direction, while the electrode assembly is designed to expand primarily axially. This ensures that expansion forces from multiple batteries do not combine to form large resultant forces, as each battery's expansion is directed along its own axis rather than laterally.
Data Source
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AI summary
A secondary battery (10) and a battery unit (20) is provided. The secondary battery (20) includes: a housing (11) including an accommodating hole (11a) with an opening; a top cover assembly (13) connected to the housing (11) in a sealed manner to cover and close the opening; an electrode assembly (12) arranged in the accommodating hole (11a), the electrode assembly (12) including more than two electrode units (121), the electrode unit (121) being formed by coiling a first electrode piece (12a), a second electrode piece (12b), and a membrane (12c), and having a wide surface (121a) and a narrow surface (121b), the more than two electrode units (121) being laminated in an axial direction (Z), and the wide surface (121a) of the electrode unit (121) being arranged facing the top cover assembly (13), wherein the top cover assembly (13) is spaced apart from the electrode assembly (12) to form a first buffer gap (14) for buffering the amount of expansion deformation of the electrode assembly (12) in the axial direction (Z). When the secondary battery (10) of this embodiment expands, the first buffer gap (14) can absorb the amount of expansion deformation to prevent the top cover assembly (13) from being disconnected from the housing (111) due to excessive stress, so as to reduce the possibility of failure of the secondary battery (10) due to damage of the overall structure, thereby ensuring the structural integrity and the safety of the secondary battery (10).