Cylindrical Cell Terminal Integration for Lower Resistance
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Solution Overview
Problem
Existing lithium-ion cells require a separate electrical conductor and pole, which occupy space and increase assembly complexity, limiting energy density and internal resistance.
Innovation Solution
An energy storage element design where the free edge strip of the cathode or anode current collector is welded to a metal part that serves as both a housing closure and conductor, eliminating the need for a separate conductor and reducing internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate electrical conductor and pole are used in lithium-ion cells, then reliable electrical connection is achieved, but device complexity and space occupation increase
Solution Approach 1:
The patent combines the electrical conductor and pole into a single integrated component. The conductor is formed as one piece that directly connects the current collectors and serves as the pole structure, eliminating the need for separate pole components and reducing assembly steps while maintaining reliable electrical connection.
Solution Approach 2:
The conductor is designed to perform multiple functions simultaneously: it serves as an electrical conductor connecting the current collectors, as a structural pole providing mechanical support, and as a component that defines the cell's terminal structure. This multi-functionality reduces the total number of components needed.
2Reliability
If a separate electrical conductor and pole are used in lithium-ion cells, then reliable electrical connection is achieved, but energy density decreases due to space occupation
Solution Approach 1:
By merging the conductor and pole into one component, the total volume occupied by electrical connection elements is reduced. This frees up space within the cell housing that can be utilized for additional active material, thereby increasing the quantity of energy-storing substance and improving energy density.
Solution Approach 2:
The unnecessary pole component is extracted from the design, removing redundant material that does not contribute to energy storage. Only the essential conductor remains, optimized to perform both conduction and structural functions, maximizing the volume available for active material.
3Ease of manufacture
If conventional electrode assembly methods are used, then manufacturing is straightforward, but internal resistance is higher
Solution Approach 1:
The conductor is pre-formed with the appropriate geometry and connection points before assembly. The current collectors are positioned and connected to the conductor in advance during the winding process, ensuring optimal electrical pathways are established before the cell is sealed, which reduces internal resistance while maintaining manufacturing simplicity.
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 design simplifies manufacturing, reduces internal resistance, and increases available volume for active material, thereby enhancing energy density and ease of assembly.
Implementation Method 1
The free edge strip of the cathode or anode current collector is welded to a metal part that serves as both a housing closure and conductor
Implementation Method 2
Electrochemical energy storage elements can convert stored chemical energy into electrical energy through virtue of a redox-reaction
Implementation Method 3
This ion current crosses the separator and is made possible by an ion-conducting electrolyte
Data Source
AI summary
An energy storage element includes an electrode-separator assembly in the form of a cylindrical winding having an anode, a separator, and a cathode. The anode includes a ribbon-shaped anode current collector with longitudinal edges and a free edge strip. The cathode includes a ribbon-shaped cathode current collector with longitudinal edges and a free edge strip. The energy storage element further includes a housing closed in an airtight and liquid-tight manner. A first longitudinal edge corresponding to a first free edge strip forms an area on which a metal part covering a first end face of the cylindrical winding lies flat, and a bottom of the housing includes an aperture into which a projection of the metal part is inserted or through which the projection protrudes.