Asynchronous Heated Calendering for Uniform Ultra-Thin Lithium Foil
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Solution Overview
Problem
The existing lithium-replenishing process for lithium-ion batteries faces challenges in achieving uniform thickness and consistent tension during the calendering of large-width lithium strips, leading to material waste, reduced production capacity, and high costs due to the need for auxiliary materials, which affects the performance of lithium metal strips.
Innovation Solution
An asynchronous heating and calendering device is used to prepare large-width ultra-thin lithium metal foil, comprising a pulling-substrate unwinding unit, lithium strip unwinding unit, asynchronous heating and calendering unit with coated rollers, and a winding unit, which unwinds, pre-shapes, and calenders the lithium strip with a pulling-substrate to achieve a composite strip with uniform thickness, using a heating box to maintain the lithium in a semi-solid state and adjust roller speeds for optimal calendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional calendering is used for large-width lithium strips, then production speed can be maintained, but thickness uniformity deteriorates due to uneven tension in the width direction
Solution Approach 1:
The patent applies dynamic speed adjustment to the calendering rollers, where the surface speed of the rollers is made variable rather than constant. The speed ratio between the driving roller and driven roller is dynamically adjusted based on real-time feedback from thickness detection devices, allowing the system to adapt to tension variations across the width of the lithium strip and maintain uniform thickness during high-speed operation.
Solution Approach 2:
The patent changes the operational parameters of the calendering process by introducing variable speed control for the rollers. The surface speed of the calendering rollers is adjusted within a specific range (0.5-5 m/min) with a controllable speed ratio (1:0.5 to 1:2), transforming the static calendering process into a dynamic one that can compensate for tension distribution issues and achieve uniform thickness calibration.
2Device complexity
If simple rolling is used to achieve ultra-thin lithium strips, then process simplicity is maintained, but thickness control deteriorates and auxiliary materials are required
Solution Approach 1:
The patent employs a composite calendering system that integrates heating functionality into the roller structure. The calendering rollers are equipped with heating devices that can independently control temperature at different positions, creating a composite functional structure that combines mechanical rolling with thermal processing to achieve precise thickness control without requiring additional auxiliary materials or complex multi-step processes.
Solution Approach 2:
The patent merges the heating function and calendering function into a single integrated process. The heating devices are built into the calendering rollers, allowing simultaneous heating and rolling operations. This combination enables the lithium strip to be heated to a semi-solid state during calendering, improving plasticity and thickness uniformity while maintaining process simplicity and avoiding the need for separate heating and rolling steps.
3Productivity
If high-speed calendering is used, then productivity is improved, but material accumulation deteriorates due to inconsistent deformation
Solution Approach 1:
The patent implements a closed-loop feedback control system where thickness detection devices continuously monitor the thickness of the lithium strip during calendering. The detected thickness data is fed back to the speed control system, which automatically adjusts the surface speed of the calendering rollers in real-time. This feedback mechanism prevents material accumulation by dynamically compensating for deformation inconsistencies that occur during high-speed calendering.
Solution Approach 2:
The patent replaces purely mechanical speed control with an intelligent control system that uses detection devices and automated speed adjustment. Instead of relying on fixed mechanical speed settings, the system uses electronic control to dynamically adjust roller speeds based on real-time thickness measurements, substituting mechanical rigidity with adaptive intelligence to prevent material accumulation during high-speed operation.
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
The device enables the production of large-width ultra-thin lithium foil with a uniform thickness of 1-20 μm and a width of 1-600 mm, achieving an initial battery efficiency of 98% with minimal material waste and reduced production costs, ensuring consistent thickness and improved performance.
Implementation Method 1
a heating box; wherein the heating box is used to heat the first calendering roller
Implementation Method 2
the first calendering roller and the second calendering roller have parallel axes and are arranged opposite to each other, so that the pulling-substrate and the lithium strip are combined into a composite strip
Data Source
AI summary
Provided are an asynchronous heating and calendering device, a large wide ultra-thin lithium metal foil, and preparation method and use thereof, wherein the asynchronous heating and calendering device comprises: a pulling-substrate unwinding unit (E) for unwinding a pulling-substrate (P); a lithium strip unwinding unit (D) for unwinding a lithium strip (S); an asynchronous heating and calendering unit (H) which comprises: a first calendering roller (B), a second calendering roller (A) and a heating box (C), wherein the heating box (C) is used to heat the first calendering roller (B), the first calendering roller (B) heats the pulling-substrate (P), and the first calendering roller (B) and the second calendering roller (A) have parallel axes and are arranged opposite to each other, so that the pulling-substrate (P) and the lithium strip (S) are combined into a composite strip (Z); and a winding unit (G) for winding the composite strip (Z). A large wide ultra-thin lithium metal foil with a uniform thickness may be prepared by providing a heating box (C) and asynchronous first calendering roller (B) and second calendering roller (A) in said device, and the application of this lithium foil in batteries has a relatively high initial efficiency. The width of the lithium foil is 1-600 mm; the thickness of the lithium foil is 1-20 μm; and the initial efficiency of the battery reaches 98%.