Cylindrical Electrode Assembly With Fixed Separator and Low Resistance
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Solution Overview
Problem
Conventional cylindrical battery cells face issues with high resistance, heat generation, and reduced current collection efficiency due to the use of strip-shaped electrode tabs, which can lead to internal short circuits and thermal runaway during rapid charging, especially as the form factor increases. Additionally, the space efficiency and assembly complexity of electrical wiring for series and parallel connections are compromised.
Innovation Solution
The electrode assembly features a fixing part attached to the separation membrane, eliminating the need for a negative electrode tab at the core region, and includes a current collector plate welded to the uncoated portions of the electrodes, with an electrode terminal riveted through a battery can opening, enhancing heat dissipation and reducing internal resistance. This design improves space efficiency and energy density while preventing separation membrane contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If strip-shaped electrode tabs are used for current collection, then the battery cell structure is simple, but resistance is high and heat generation is excessive
Solution Approach 1:
The electrode tab is segmented into multiple finger-like protrusions instead of a single strip shape. This segmentation increases the surface area for current collection and distributes the current flow across multiple contact points with the current collector plate, thereby reducing resistance and heat generation while maintaining structural simplicity
Solution Approach 2:
The electrode tab transitions from a two-dimensional strip shape to a three-dimensional finger-like structure with multiple protrusions. This dimensional change increases the effective surface area and improves spatial distribution of current collection, reducing resistance without significantly increasing overall device complexity
2Quantity of substance
If the battery cell form factor is increased for electric vehicle application, then the energy capacity is improved, but heat generation around the electrode tab increases causing thermal runaway risk
Solution Approach 1:
The electrode tab is divided into multiple finger-like segments that distribute the current collection across several contact points. This segmentation reduces the current density at each contact point, lowering heat generation and thermal runaway risk while enabling larger battery cell form factors for electric vehicle applications
Solution Approach 2:
The electrode tab structure is locally optimized with finger-like protrusions at the current collection region. This local structural modification improves heat dissipation and current distribution specifically where needed, allowing the rest of the battery cell to be scaled up for higher capacity without proportionally increasing thermal risk
3Stability of the object's composition
If a negative electrode tab is coupled to the core region to fix the separation membrane, then the separation membrane stability is improved, but the space efficiency and assembly complexity are reduced
Solution Approach 1:
The finger-like electrode tab protrusions serve multiple functions: they collect current, provide structural support to the separation membrane through their presence in the core region, and eliminate the need for separate tab components. This multi-functionality maintains separation membrane stability while reducing assembly complexity and improving space efficiency
Solution Approach 2:
The current collection function and separation membrane support function are merged into a single integrated structure. The finger-like protrusions of the electrode tab simultaneously perform both functions, eliminating the need for separate negative electrode tabs and simplifying the overall assembly
4Power
If multiple battery cells are connected in series and parallel to achieve required output voltage and capacity, then the electrical performance is improved, but the assembly complexity and wiring requirements increase
Solution Approach 1:
The current collector plate serves as both the current collection component and the electrical connection interface for series and parallel configurations. This multi-functionality simplifies wiring requirements and reduces assembly complexity while maintaining the ability to achieve required output voltage and capacity through multiple cell connections
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 reduces internal resistance, increases energy density, and enhances safety by preventing separation membrane contraction, allowing for larger battery cell sizes and more efficient electrical connections, thereby addressing the challenges of heat management and assembly complexity.
Implementation Method 1
a current collector plate welded to uncoated portions of the electrodes, with an electrode terminal riveted through a battery can opening
Implementation Method 2
a fixing part which is provided on the electrode active material layer, provided to an edge portion closest to a winding center of the electrode assembly, and is fixed to at least a part of the separation membranes, thereby it is possible to prevent the separation membrane from being contracted due to a high temperature
Data Source
AI summary
An electrode assembly includes a first electrode, a separation membrane, and a second electrode are stacked and wound, in which at least one of the first electrode and the second electrode includes a current collector and an electrode active material layer provided on the current collector, and the first electrode includes a fixing part which is provided on the electrode active material layer, provided to an edge portion closest to a winding center of the electrode assembly, and is fixed to the separation membrane. Further, a battery cell includes the electrode assembly; a battery can which accommodates the electrode assembly and has an opening at one side; an electrode terminal riveted through a through-hole formed in a bottom of the battery can; a gasket provided between the electrode terminal and an outer diameter of the through-hole; and a sealing body sealing the opening of the battery can.