Cell Stack Adhesive Bonding via Induction Heating
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Solution Overview
Problem
Existing methods for bonding cell stack layers in electrochemical storage devices, such as lithium-ion batteries, result in inhomogeneous temperature distribution and uneven bonding, which hinders the production process and can adversely affect material properties.
Innovation Solution
The method involves electromagnetically heating electrically conductive layers within the cell stack using magnetic coils to induce eddy currents, directly activating adhesives and ensuring uniform temperature distribution, thereby bonding the anode, separator, and cathode layers efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heating plates are used to heat cell stack layers from outside, then the bonding process can be initiated, but inhomogeneous temperature distribution occurs and bonding uniformity deteriorates
Solution Approach 1:
The patent replaces the mechanical heating system (heating plates) with an electromagnetic induction heating system. Magnetic coils generate a time-varying magnetic field that induces eddy currents in the electrically conductive layers, converting electromagnetic energy directly into heat within the layers themselves. This substitution eliminates the thermal gradient problem caused by external heating and achieves homogeneous temperature distribution throughout the cell stack.
Solution Approach 2:
The patent employs periodic alternating current through the magnetic coils to generate a time-varying magnetic field. This periodic action induces continuous eddy currents in the conductive layers, maintaining sustained heating. The frequency of the alternating current can be optimized to achieve the desired heating rate and temperature distribution uniformity throughout the cell stack.
2Reliability
If heating time is extended to achieve complete heating of all layers, then bonding can be achieved, but productivity decreases
Solution Approach 1:
The electromagnetic induction heating system generates heat directly within the electrically conductive layers through induced eddy currents, eliminating the time-consuming process of heat conduction from external plates. This direct internal heating mechanism rapidly achieves the required temperature throughout all layers simultaneously, significantly reducing heating time while ensuring complete and uniform bonding.
Solution Approach 2:
The patent changes the heating parameter from external thermal conduction to internal electromagnetic energy conversion. By adjusting the frequency and amplitude of the alternating current in the magnetic coils, the heating rate and temperature distribution can be precisely controlled, enabling rapid heating that both completes bonding and maintains high productivity.
3Productivity
If greater force or higher temperature is applied to accelerate bonding, then bonding speed increases, but material properties deteriorate
Solution Approach 1:
The patent changes the heating method to electromagnetic induction, which provides precise control over temperature distribution. The time-varying magnetic field induces eddy currents that generate heat uniformly throughout the conductive layers, allowing the adhesive to be activated at optimal temperatures without excessive thermal stress. This controlled parameter change accelerates bonding while preserving material properties.
Solution Approach 2:
The electromagnetic induction heating system provides localized and uniform heating specifically within the electrically conductive layers where the adhesive is located. The time-varying magnetic field penetrates the layers and generates heat directly at the bonding interfaces, ensuring uniform temperature distribution and consistent adhesive activation across all layers without creating hot spots that could damage materials.
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 approach reduces heating time, prevents thermal stress on outer layers, maintains material integrity, and ensures a homogeneous temperature distribution across the cell stack, facilitating rapid and uniform bonding without adverse material changes.
Implementation Method 1
at least one heat source (20, 21) is provided, which electromagnetically heats the electrically conductive layers (101, 102) of the bundle by inducing eddy currents
Implementation Method 2
electromagnetically heats the electrically conductive layers (101, 102) of the bundle by inducing eddy currents
Implementation Method 3
electromagnetically heats the electrically conductive layers (101, 102) of the bundle by inducing eddy currents
Data Source
Figure 1~2
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Figure 5
AI summary
The invention relates to a method for producing a cell stack, in particular for an electrochemical store, wherein at least anode electrodes, separator layers and cathode electrodes are repeatedly stacked or folded or wound on top of one another, wherein at least one layer is coated on one side or on both sides with a thermally activatable adhesive or is provided with said adhesive, wherein electrically conductive layers, in particular the anode electrodes and/or the cathode electrodes, are electromagnetically and/or electrically heated, wherein as a result of the heating of the electrically conductive layers, the adhesive is thermally activated and in particular the anode electrodes, separator layers and cathode electrodes are connected to one another to form a cell stack. The invention also relates to a device for producing cell stacks and to an electrochemical store having at least one cell stack.