Tab-Free Electrode Layers for Uniform Battery Cell Current Distribution
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Solution Overview
Problem
Existing battery cell manufacturing processes face challenges in efficiently attaching and electrically connecting electrodes, leading to inefficiencies in current distribution and increased dead volume.
Innovation Solution
The proposed solution involves forming electrode layers with coated and uncoated portions, where the uncoated portions serve as connection points without the need for cutting or notching, allowing for a more uniform current distribution and reduced dead volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If tabs are formed by notching or cutting metal foil material, then electrical connection is achieved, but manufacturing complexity and dead volume increase
Solution Approach 1:
The invention extracts the connection function from the active material coating by creating uncoated portions of the conductive foil. These uncoated portions serve purely as connection tabs, separating the active material function from the electrical connection function. This eliminates the need for notching or cutting operations while reducing structural complexity.
Solution Approach 2:
Instead of removing material to create tabs (cutting/notching), the invention inverts the approach by selectively retaining conductive material in uncoated portions. The tabs are formed by what is left uncovered rather than what is removed, simplifying the manufacturing process and eliminating dead volume associated with cutout tabs.
2Ease of operation
If tabs extend beyond the cell stack height, then electrical connection is facilitated, but dead volume increases
Solution Approach 1:
The invention applies local quality by creating uncoated portions with specific properties (pure conductive material) only where needed for connection, while the rest of the foil maintains its active material coating. The uncoated tabs extend just enough to facilitate connection without excessive length, minimizing dead volume while ensuring adequate electrical connection capability.
3Reliability
If active material coats the entire foil surface, then electrochemical performance is maximized, but connection area is reduced
Solution Approach 1:
The invention segments the foil surface into two distinct zones: coated portions for electrochemical activity and uncoated portions for electrical connection. This segmentation allows the active material to cover only the areas needed for electrochemical performance while dedicating separate uncoated regions for robust electrical connection, eliminating the trade-off between the two functions.
Solution Approach 2:
Different regions of the foil are given different properties: the coated regions provide electrochemical functionality while the uncoated regions provide optimal electrical connection properties. This local differentiation ensures both high electrochemical performance and adequate connection area without compromise.
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 approach facilitates improved attachment and electrical connection of electrodes, enhancing current distribution uniformity and reducing the volume required for connection, thereby optimizing battery cell performance and manufacturing efficiency.
Implementation Method 1
the uncoated connection portion configured to be electrically connected to another electrode layer
Implementation Method 2
the coated portion includes an active material coating a surface of the coated portion
Data Source
AI summary
A battery cell includes a housing enclosing an anode and a cathode, and an electrode assembly disposed in the housing, the electrode assembly including a plurality of electrode layers forming a cell stack. Each electrode layer has a coated portion forming part of the cell stack and an uncoated connection portion extending away from the cell stack, the coated portion having a first height, the uncoated connection portion configured to be electrically connected to another electrode layer, the uncoated connection portion having a second height that is equal to the first height.