Cylindrical Energy Storage Cell With Welded Edge-Strip Terminals
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Solution Overview
Problem
Existing lithium-ion cells face challenges in achieving high energy density and efficient electrical conductivity, particularly in applications requiring high currents and compact form factors, such as those used in automotive and e-bike sectors.
Innovation Solution
The design of an energy storage cell with a ribbon-shaped anode and cathode current collectors, where free edge strips protrude from the terminal end faces, allowing direct welding to a lid assembly, eliminating the need for separate conductors and enhancing electrical contact, thereby reducing internal resistance and increasing usable volume for active materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate conductors are used to connect current collectors to terminals, then electrical connection is achieved, but device complexity and internal resistance increase
Solution Approach 1:
The patent merges the conductor function with the current collector by extending the current collector itself to form the electrical connection to the terminal. This eliminates separate conductor components, reducing structural complexity while maintaining reliable electrical connection. The current collector is designed to protrude from the winding and directly contact the terminal, integrating two previously separate functions into one component.
2Use of energy by moving object
If current collectors are fully loaded with active material, then energy density is maximized, but electrical conductivity at edges is reduced
Solution Approach 1:
The patent applies local quality by creating a free edge strip on the current collector that is not loaded with active material. This localized region maintains high electrical conductivity for the electrical connection to the terminal, while the rest of the current collector is fully loaded with active material to maximize energy density. The solution optimizes different regions of the same component for different functions.
3Use of energy by moving object
If more active material is used, then energy density increases, but manufacturing precision and handling become more difficult
Solution Approach 1:
The patent applies preliminary action by pre-forming the current collector with an extended free edge strip during the manufacturing process. This preliminary structural preparation facilitates easier handling and precise positioning during assembly, as the extended edge provides a ready-made connection point that simplifies the manufacturing process while allowing maximum active material loading.
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 energy density and improves electrical conductivity, enabling the cell to handle high currents effectively while maintaining a compact form factor, suitable for applications in motor vehicles.
Implementation Method 1
The metallic membrane is configured to bulge or burst outwards from a defined excess pressure inside the housing
Implementation Method 2
The free edge strip protruding from the first terminal end face is welded to the contact element of the lid assembly
Implementation Method 3
Electrochemical energy storage elements can convert stored chemical energy into electrical energy through virtue of a redox-reaction
Implementation Method 4
They are based on the use of lithium, which can migrate back and forth between the electrodes of the cell in the form of ions
Data Source
AI summary
An energy storage cell includes an electrode-separator assembly comprising a ribbon-shaped anode, a ribbon-shaped cathode, and a separator. The anode and the cathode are formed and/or arranged within the electrode-separator assembly, which is formed as a cylindrical winding with a first terminal end face and a second terminal end face, such that a free edge strip of a cathode current collector or a free edge strip of an anode current collector protrudes from the first terminal end face. The energy storage cell further includes a housing closed in an airtight and liquid-tight manner and enclosing an interior space in which the electrode-separator assembly is arranged. The housing includes a metallic housing cup and a lid assembly. The lid assembly includes a metallic contact element. The free edge strip protruding from the first terminal end face is welded to the contact element of the lid assembly.