Cylindrical Electrode Assembly Adhesive Fixation Against Unwinding
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Solution Overview
Problem
Existing secondary batteries face issues with internal stress at the winding end of the electrode assembly, which can lead to unwinding and compromise the structural integrity and internal space of the case.
Innovation Solution
The secondary battery incorporates an adhesive part along the boundary line of the winding end of the electrode assembly, which is fixed using patterns or continuous patterns, and includes first and second adhesive parts to secure the outermost surface of the separator, reducing the likelihood of unwinding and internal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the winding end of the electrode assembly is left unwound to simplify manufacturing, then the manufacturing process is easier, but internal stress accumulates and structural integrity deteriorates
Solution Approach 1:
The adhesive part is divided into multiple segments: a first adhesive part extending in the winding direction and a second adhesive part extending in the axial direction. This segmentation allows the adhesive structure to address stress in multiple directions independently, preventing unwinding while maintaining manufacturing simplicity
Solution Approach 2:
The adhesive part is applied to the winding end before the electrode assembly is fully assembled into the case. This preliminary application of adhesive prevents internal stress accumulation from causing unwinding during subsequent assembly and operation, ensuring structural integrity from the outset
2Reliability
If adhesive parts are added to fix the winding end, then structural integrity is improved, but device complexity increases
Solution Approach 1:
The adhesive part is applied locally only at the winding end of the electrode assembly where stress concentration occurs, rather than throughout the entire structure. This localized application provides necessary structural reinforcement while minimizing added complexity and material usage
Solution Approach 2:
The adhesive part combines two different adhesive configurations (first adhesive part in winding direction and second adhesive part in axial direction) to create a composite adhesive structure that addresses multiple stress vectors simultaneously, providing enhanced structural integrity without requiring separate adhesive applications
3Reliability
If the adhesive part covers the entire winding end, then unwinding prevention is improved, but internal space of the case is reduced
Solution Approach 1:
The adhesive part is segmented into two directional components rather than forming a continuous full-coverage layer. This segmentation reduces the total adhesive material required while maintaining effective prevention of unwinding through the strategically oriented adhesive segments
Solution Approach 2:
Instead of applying adhesive over the entire winding end surface, the adhesive is applied partially in specific directions (winding direction and axial direction) where it is most needed to prevent unwinding. This partial action provides sufficient structural reinforcement while minimizing space occupation
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
The adhesive fixation effectively maintains the wound shape of the electrode assembly, preventing unwinding and reducing internal stress, thereby ensuring the structural integrity and internal space of the case.
Implementation Method 1
an adhesive part adhering and fixing a winding end of an outermost surface of the electrode assembly
Implementation Method 2
The adhesive part may be fixed to the outermost surface by heat fusion
Data Source
AI summary
One or more embodiments relates to a secondary battery capable of suppressing internal stress of the side of the electrode assembly, and capable of ensuring internal space of a case. The secondary battery according to one or more embodiments includes a case defining a space therein, an electrode assembly in the case and including a positive electrode plate, a negative electrode plate, and a separator wound in a cylindrical shape, and an adhesive part adhering and fixing a winding end of an outermost surface of the electrode assembly, and a cap assembly sealing the case.