Prismatic Battery Joining Curvature Detachment
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Solution Overview
Problem
Conventional prismatic secondary batteries face detachment issues at the joining portion between the electrode assembly and the current collector due to bending deformation, which existing structures do not adequately prevent.
Innovation Solution
A battery design featuring a layered portion with a first and second protrusion/recess region, where the second region is 1.3 to 2.0 times wider than the first, and ultrasonic joining using a horn and anvil with a corresponding width ratio to form a curved connection, enhancing the bending strength and preventing detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional welding is used to join the electrode assembly to the current collector, then the joining process is simple, but bending deformation occurs causing detachment at the joining portion
Solution Approach 1:
The patent applies curvature by forming a curved portion at the joining portion between the layered portion and current collector. This curved shape increases the bending strength of the joining portion, preventing detachment when bending deformation occurs during battery assembly or use. The curvature transforms the rigid linear connection into a flexible arc that better withstands mechanical stress.
Solution Approach 2:
The patent changes geometric parameters by forming protrusion/recess regions with specific width ratios (1.3 to 2.0 times). This parameter modification increases the surface area and mechanical interlocking at the joining portion, enhancing the bond strength and resistance to detachment while maintaining manufacturing feasibility through ultrasonic welding.
2Device complexity
If the current collector structure is simplified to reduce manufacturing complexity, then production is easier, but bending deformation cannot be suppressed
Solution Approach 1:
The patent segments the joining portion into distinct regions: a flat portion for ultrasonic welding and a curved portion for enhanced bending strength. This segmentation allows each region to perform its specific function optimally - the flat portion provides a stable welding surface while the curved portion resists bending deformation, achieving high strength without overall structural complexity.
Solution Approach 2:
The curved portion with specific radius of curvature is introduced at the joining portion to inherently resist bending deformation. This geometric feature provides mechanical strength against bending forces during battery assembly and operation, eliminating the need for complex reinforcement structures while maintaining manufacturing simplicity.
3Reliability
If protrusion/recess regions with large width ratio are formed, then detachment resistance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies a width ratio range (1.3 to 2.0 times) for the protrusion/recess regions, providing sufficient dimensional tolerance that ensures adequate detachment resistance without requiring extremely precise manufacturing. This partial specification approach achieves reliable performance while accommodating normal manufacturing variations.
Solution Approach 2:
By defining specific parameter ranges for the protrusion/recess region widths and their ratio, the patent optimizes the balance between detachment resistance and manufacturing precision. The specified ratio range ensures adequate mechanical interlocking and bond strength while remaining achievable through conventional ultrasonic welding processes.
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 solution effectively suppresses detachment between the electrode assembly and current collector by increasing the bending strength of the connection, ensuring reliable performance during manufacturing and usage.
Implementation Method 1
ultrasonically joining the first outer surface of the layered portion and a current collector to each other. The ultrasonically joining includes: placing a horn on the layered portion side and placing an anvil on the current collector side
Data Source
AI summary
A layered portion is formed by layering an electrode core body. The layered portion has a first outer surface and a second outer surface opposite to each other. The first outer surface of the layered portion is connected to a current collector that is in a form of a plate. A first protrusion/recess region is formed in the second outer surface of the layered portion. A second protrusion/recess region is formed in an outer surface of the current collector located opposite to the layered portion. A width of the second protrusion/recess region is 1.3 times or more and 2.0 times or less as large as a width of the first protrusion/recess region. A curved portion is formed at a portion at which the layered portion and the current collector are connected to each other.