Electrode Assembly Weld Seam Layout for Lower ESR in Supercapacitors
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Solution Overview
Problem
Existing ultracapacitors face challenges in achieving optimal thermal, electrical, and mechanical characteristics due to suboptimal weld seam geometries in connecting current collectors to electrode assemblies, leading to high equivalent series resistance (ESR) and thermal heating during high power demands.
Innovation Solution
The method involves forming specific weld seam geometries, including transport and collector weld seams, oriented along radial and circumferential directions of the electrode assembly to enhance current flow efficiency, reducing ESR and thermal heating by optimizing the weld seam arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional weld seam geometries are used to connect current collectors to electrode assemblies, then the manufacturing process is simple, but the equivalent series resistance (ESR) is high and thermal heating occurs during high power demands
Solution Approach 1:
The weld seam is divided into multiple distinct segments or zones with different geometries and orientations. Each segment serves a specific function: some segments are optimized for current collection while others are optimized for heat dissipation. This segmentation allows the weld seam to simultaneously achieve low ESR and effective thermal management without requiring a completely complex new design.
Solution Approach 2:
Different portions of the weld seam are given different local qualities or characteristics. Specifically, certain areas have enhanced cross-sectional areas or modified geometries tailored to their local functional requirements - such as improved current distribution in high-current zones or optimized thermal conduction in heat-prone areas. This local optimization reduces overall ESR and thermal heating while maintaining manufacturing feasibility.
2Loss of energy
If weld seam geometry is optimized to reduce ESR and thermal heating, then electrical and thermal performance improves, but manufacturing complexity increases
Solution Approach 1:
The invention optimizes specific parameters of the weld seam geometry - such as cross-sectional area, length, orientation, and distribution pattern - to minimize energy loss during charging and discharging. By carefully adjusting these geometric parameters within practical manufacturing ranges, the patent achieves reduced ESR and thermal heating while maintaining ease of manufacture. The optimization focuses on key parameters that have the greatest impact on energy loss.
Solution Approach 2:
Rather than optimizing every aspect of the weld seam geometry, the invention applies partial optimization to the most critical segments or regions. This partial action approach targets the specific areas that contribute most to energy loss, achieving significant improvements in electrical and thermal performance without requiring complete redesign of the entire welding process, thus maintaining manufacturing simplicity.
3Reliability
If straight-line welding geometry is used between start and end points, then manufacturing is simple, but current flow efficiency is suboptimal leading to high ESR
Solution Approach 1:
The weld seam design transitions from simple one-dimensional straight-line connections to two-dimensional or three-dimensional geometries. By adding dimensional complexity - such as curved paths, varied cross-sections, or multi-level structures - the weld seam can better follow optimal current flow paths and distribute current more efficiently. This dimensional enhancement improves current flow efficiency and reduces ESR while remaining controllable with standard welding precision.
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 proposed weld seam configurations improve the thermo-electrical properties of ultracapacitors by reducing ESR and heat generation during charging and discharging, thereby enhancing efficiency and extending the cell's lifetime.
Implementation Method 1
moving the welding implement relative to the welding surface to weld each cell component to the electrode assembly by forming a plurality of weld seams on the welding surface
Data Source
AI summary
A method for welding a cell component to an electrode assembly of an energy storage cell such as a supercapacitor by: arranging each cell component and the electrode assembly in contact with each other, each cell component has an exposed welding surface accessible for welding by a welding implement; and, moving the welding implement relative to the welding surface to weld each cell component to the electrode assembly by forming a plurality of weld seams on the welding surface. At least two of the formed weld seams are chosen from a group of weld seam types which includes a transport weld seam that has a main directional component along a radial direction of the electrode assembly and a collector weld seam that has a main directional component along a circumferential direction of the electrode assembly.