Battery Cell Tab Structure for High-Density Electrode Welding
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Solution Overview
Problem
Existing battery cells face challenges in maximizing energy density due to the limitations of conventional welding methods that occupy significant space, reducing the volume available for active electrode material.
Innovation Solution
A T-shaped sub tab is used to facilitate a small welding area between the current collector and electrode foils, allowing for a larger volume of active material within the electrode stack by minimizing the space required for electrical coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional welding methods are used to electrically couple the current collector with the electrode, then reliable electrical connection is achieved, but significant space is occupied reducing the volume available for active electrode material
Solution Approach 1:
The welding process is segmented into two separate operations: first welding the tab to the uncoated region of the electrode, then welding the current collector to the tab. This segmentation allows each welding operation to use optimized parameters and minimizes the total welding area required, thereby increasing the volume available for active electrode material while maintaining reliable electrical connection.
Solution Approach 2:
The tab serves as an intermediary component between the current collector and the electrode. By introducing this intermediate element, the patent enables electrical coupling through a smaller effective welding area compared to direct welding methods, thus resolving the contradiction between connection reliability and volume availability for active material.
2Strength
If larger welding area is used for electrical coupling, then welding strength and reliability are improved, but the volume for active material is reduced
Solution Approach 1:
The welding strength requirement is distributed across two separate welding joints (tab-to-electrode and current collector-to-tab) rather than requiring a single large weld. Each joint can be optimized for strength with minimal area, achieving overall structural integrity while minimizing volume consumption.
Solution Approach 2:
The tab is designed with specific geometric features including an uncoated region that provides optimal local properties for welding to the electrode, while other portions of the tab are configured for optimal welding to the current collector. This localized optimization of welding surfaces ensures sufficient strength with minimal total welding area.
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
This configuration increases the energy density of the battery cell by enabling a larger volume of active material, enhancing the cell's energy output per volume.
Implementation Method 1
welding a portion of a tab with an uncoated region of an electrode... welding the current collector with another portion of the tab to electrically couple the current collector with the uncoated region of the electrode
Data Source
AI summary
A battery cell can include a tab having a first portion and a second portion. The battery cell can include an electrode having an uncoated region. The battery cell can include a current collector. The tab can be disposed within a slit of the current collector. The first portion and the second portion of the tab can electrically couple the current collector with the electrode via the uncoated region of the electrode.