Prismatic Battery Rib With Bendable Part
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Solution Overview
Problem
Prismatic secondary batteries face the risk of short circuits between the outer can and the current collector due to deformation, particularly on the negative electrode side where copper or copper alloys are used, as the rib of the current collector may penetrate the resin insulation sheet, leading to potential short circuits.
Innovation Solution
A prismatic battery design featuring a current collector with a rib that has an easily bendable part, such as a thin-wall, groove, or notch, which narrows the rib's width, preventing the rib from penetrating the insulation member even if the outer can deforms, thus preventing short circuits and allowing for effective sputter diffusion prevention during resistance welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the rib of the current collector is made rigid to prevent deformation, then structural strength is improved, but the rib may penetrate the insulation member during outer can deformation causing short circuits
Solution Approach 1:
The rib is designed with a flexible portion that allows it to dynamically adjust its rigidity - remaining rigid under normal conditions for structural support, but becoming flexible when the outer can deforms to prevent penetration of the insulation member and avoid short circuits
Solution Approach 2:
The rib's physical parameters are changed by introducing a flexible portion with different material properties or structural characteristics (such as reduced thickness or different material composition) compared to the main body of the rib, enabling it to bend under deformation while maintaining strength during normal operation
2Reliability
If copper or copper alloys are used for the negative electrode current collector to reduce electrical resistance, then electrical conductivity is improved, but the material hardness increases making the rib more likely to penetrate the insulation member
Solution Approach 1:
Different portions of the current collector are made with different material properties - the main body uses copper or copper alloys for high electrical conductivity, while the flexible portion uses a softer material or different structure to prevent penetration of the insulation member
3Strength
If the rib width is uniform throughout to maintain structural integrity, then strength is improved, but sputter diffusion cannot be effectively prevented during resistance welding
Solution Approach 1:
The rib width varies at different locations - the base portion has sufficient width for structural integrity, while the tip portion is narrowed to effectively prevent sputter diffusion during resistance welding operations
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 design enhances the battery's resistance to short circuits and sputter diffusion, maintaining structural integrity and electrical performance under deformation and vibration conditions, while also improving the production efficiency and quality of the resistance-welded parts.
Implementation Method 1
Sputters occur at the contact part between the electrode rod and current collector when the electrode substrate exposed portion of the electrode plate is bonded with the current collector by resistance welding. In order to prevent these sputters from diffusing to the electrode assembly side, a lib for preventing sputter diffusion is disposed on the electrode assembly side of the current collector.
Implementation Method 2
Though there are a mechanical caulking method, ultrasonic welding method, laser welding method, and resistance welding method as the method for collecting current by electrically bonding the electrode substrate exposed portion of an electrode plate with the current collector, a resistance welding method is suitable for batteries which need a large current and high output
Implementation Method 3
the rib is formed with an easily bendable part provided with a thin-wall part, groove part, opening part or notch part which narrows the width of the rib in a region excluding a tip part of the rib
Data Source
AI summary
Provided is a prismatic battery resistant to the development of short circuits. The prismatic battery has a structure in which a flat electrode including a positive electrode collector with a positive electrode substrate exposed portion and a negative electrode collector with a negative electrode substrate exposed portion is accommodated in an outer can. At least one of the positive electrode collector and the negative electrode collector has a rib. The rib is provided with an easily bendable part (a thin wall, groove, opening, or notch). The rib is bent at the easily bendable part when force is applied to the tip of the rib to prevent the tip from reaching the outer can by means of an insulation sheet to avoid the development of short circuits between the negative electrode collector and the outer can.