Asymmetric Li-Ion Cell Contact Layout for Fast-Charging Conductivity
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Solution Overview
Problem
Existing lithium-ion cells face challenges in achieving high energy density and efficient electrical and thermal conductivity while minimizing weight and volume, particularly in applications requiring high currents and fast charging, such as in the automotive sector.
Innovation Solution
The energy storage cell design features a ribbon-shaped electrode-separator assembly with asymmetric contact, where one electrode's longitudinal edge protrudes from one end face and is connected via a metallic arrester strip, while the other electrode is connected via the housing part, utilizing an airtight and liquid-tight housing with an insulating seal to optimize electrical and thermal connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the electrode-separator assembly is wound into a cylindrical winding with asymmetric contact, then energy density is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies asymmetry by creating an asymmetric contact structure where only one longitudinal edge of the first current collector protrudes from the winding and is connected to the housing, while the second current collector is connected through the housing part. This asymmetric design optimizes space utilization and improves energy density while maintaining manageable manufacturing complexity through a systematic assembly approach.
2Power
If metallic arrester strips are used to connect electrodes to housing, then electrical and thermal conductivity is improved, but weight increases
Solution Approach 1:
The patent applies local quality by using metallic arrester strips only at specific locations where electrical and thermal connection is required (at the protruding longitudinal edges), rather than throughout the entire electrode structure. This localized application provides necessary conductivity while minimizing additional weight compared to comprehensive metallic reinforcement.
3Ease of operation
If the first current collector is connected directly to housing bottom or lid, then electrical connection is simplified, but thermal management efficiency decreases
Solution Approach 1:
The patent introduces an intermediary metallic arrester strip that mediates between the first current collector and the housing connection. This intermediary element facilitates both electrical connection and thermal management by providing a dedicated thermal conduction path while maintaining electrical connectivity, thus resolving the trade-off between connection simplicity and thermal efficiency.
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 enhances energy density, improves electrical and thermal conductivity, reduces weight and volume, and supports fast charging capabilities, minimizing lithium plating during high-rate charging and low temperatures.
Implementation Method 1
at least one metallic arrester strip is fixed to the second ribbon-shaped current collector... The at least one metallic arrester strip fixed to the second current collector is either welded to the lid component or to a pole passing through the lid component
Implementation Method 2
improves electrical and thermal conductivity... The at least one metallic arrester strip fixed to the second current collector is either welded to the lid component or to a pole passing through the lid component, while the first longitudinal edge of the first current collector is welded to the bottom or to a metal sheet resting directly on the bottom
Implementation Method 3
Electrochemical energy storage elements can convert stored chemical energy into electrical energy through virtue of a redox-reaction... During a discharge, electrons are released at the negative electrode as a result of an oxidation process
Implementation Method 4
This ion current crosses the separator and is made possible by an ion-conducting electrolyte... an ion current corresponding to the electrode reaction occurs within the cell
Data Source
AI summary
An energy storage cell includes an electrode-separator assembly with the sequence first electrode/separator/second electrode. The first electrode is ribbon-shaped and includes a first ribbon-shaped current collector with a first longitudinal edge, a second longitudinal edge parallel thereto, a main region loaded with a layer of first electrode material, and a free edge strip extending along the first longitudinal edge and being not loaded with the first electrode material. The second electrode is ribbon-shaped and includes a second ribbon-shaped current collector with a first longitudinal edge and a second longitudinal edge parallel thereto. The second ribbon-shaped current collector is loaded with a layer of second electrode material and at least one metallic arrester strip is fixed to the second ribbon-shaped current collector. The at least one metallic arrester strip fixed to the second current collector protrudes from the first terminal end face of the electrode-separator assembly.