Jelly-Roll Electrode Assembly with Cathode Loading Reduction
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Solution Overview
Problem
Existing electrode assemblies face limitations in achieving high energy density due to the precipitation of metallic lithium at boundaries where the anode active material loading is reduced, leading to safety concerns and reduced capacity.
Innovation Solution
The electrode assembly design includes a cathode active material portion with a loading reduction portion and an anode uncoated portion extending in opposite directions, with a gradual decrease in loading amount, and an insulating layer to prevent lithium deposition, allowing for a tab-less structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a wound rotor type induction motor is used to secure high starting torque, then the starting torque is improved, but the structure becomes more complex and costly due to additional components like slip rings and carbon brushes
Solution Approach 1:
The patent replaces the mechanical rotor structure (wound rotor with slip rings and carbon brushes) with a simpler squirrel cage rotor design. The high starting torque function is achieved not through mechanical means but through electronic control of the stator winding connections, substituting a mechanical system with an electronic control system.
Solution Approach 2:
The patent employs dynamic switching of stator winding connections during the motor starting process. The controller dynamically changes the winding configuration from delta to star connection, allowing the motor to achieve high starting torque initially and then transition to normal operation, making the system adaptable rather than static.
2Force
If a wound rotor type induction motor is used to secure high starting torque, then the starting torque is improved, but the manufacturing cost increases due to additional components
Solution Approach 1:
The patent eliminates expensive mechanical components (slip rings, carbon brushes, rotor windings) by using a squirrel cage rotor design. The high starting torque function is achieved through electronic control of the stator side, significantly reducing manufacturing costs while maintaining the desired performance.
Solution Approach 2:
The patent extracts and removes the complex and costly wound rotor components from the motor design. By taking out the slip rings, carbon brushes, and rotor windings, the design achieves cost reduction while the essential function of high starting torque is maintained through stator winding control.
3Speed
If star-delta switching is used to reduce starting current, then the starting current is reduced, but the starting torque becomes insufficient for high-load applications
Solution Approach 1:
The patent implements dynamic control of stator winding connections, transitioning from a static star-delta switching approach to a dynamic sequence controlled by a microprocessor. This allows optimization of both starting current and starting torque by precisely controlling the timing and sequence of winding reconfiguration based on actual motor conditions.
Solution Approach 2:
The patent changes the electrical parameters (winding connections, phase configurations) dynamically during the starting process. By altering the connection topology from delta to star at optimized moments, the system achieves both reduced starting current and maintained starting torque, resolving the contradiction between these two parameters.
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 by maintaining a high N/P ratio and preventing lithium precipitation, thereby improving safety and capacity without the need for additional electrode tabs.
Implementation Method 1
The inverter is constructed by modularly combining a plurality of switches and diodes and controlling three-phase power supplied to the motor in a state where the semiconductor devices are switched
Data Source
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AI summary
An electrode assembly according to an embodiment of the present disclosure includes an anode; a cathode; and a separator disposed between the anode and the cathode, wherein the anode, the cathode and the separator are rolled together to form a j elly-roll structure, wherein the anode includes an anode current collector and an anode active material portion formed by applying an anode active material onto the anode current collector, wherein the cathode includes a cathode current collector and a cathode active material portion formed by applying a cathode active material onto the cathode current collector, wherein an anode uncoated portion, to which the anode active material is not applied among the anode current collector, extends in a first direction, wherein a cathode uncoated portion, to which the cathode active material is not applied among the cathode current collector, extends in a second direction opposite to the first direction, wherein the cathode active material portion includes a loading reduction portion in which the loading amount of the cathode active material is smaller than that of the adjacent region, and wherein the loading reduction portion is disposed at one end part of the cathode in the first direction.