Dry Electrode Coating with Uniform Powder Dosing
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Solution Overview
Problem
Conventional methods for producing lithium-ion battery electrodes are costly and lack process reliability due to uneven material distribution and potential pre-compaction during the coating process.
Innovation Solution
A dry coating method using a discharge system with rotating calender rollers and a dosing concept that ensures temporal and spatially constant powder dosing, utilizing a reservoir, transport chute, and vibrational excitation to maintain uniform distribution and prevent pre-compaction, along with a control loop for precise fill level management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wet coating process with viscous electrode material mass is used, then the coating can be applied to the current collector foil, but the production costs increase and process reliability decreases due to uneven material distribution
Solution Approach 1:
The patent changes the physical state of the electrode material from viscous (wet coating) to powdered (dry coating). This parameter change eliminates the need for solvents and complex drying processes, reducing production costs while improving material distribution uniformity and process reliability through precise gravitational dosing
Solution Approach 2:
The patent replaces the complex wet coating mechanical system (discharge system, drying station, calender roll mill) with a simpler dry coating system using gravitational flow and roller compaction. This substitution reduces equipment complexity and operational costs while maintaining coating quality
2Manufacturing precision
If powder is filled into the roller gap without controlled dosing, then the coating width can be covered, but uneven distribution and pre-compaction occur
Solution Approach 1:
The patent introduces a transport chute as an intermediary element between the reservoir and roller gap. This chute provides a controlled pathway for powder flow, ensuring uniform distribution across the coating width while preventing direct contact with roller surfaces that would cause pre-compaction
Solution Approach 2:
The patent positions the transport chute and roller gap at the same gravitational potential level. This equipotential arrangement allows powder to flow smoothly under gravity without requiring additional mechanical force, achieving uniform dosing while minimizing system complexity
3Productivity
If the roller gap is filled with powder, then coating can be produced, but pre-compaction occurs leading to increased torques and potential drive failure
Solution Approach 1:
The patent extracts the powder from direct contact with the roller surfaces by using the transport chute as an intermediate delivery mechanism. The powder is introduced into the roller gap from the side rather than being stored in the gap, preventing pre-compaction while maintaining continuous coating production
Solution Approach 2:
The patent performs preliminary distribution of powder through the transport chute before the material enters the roller gap. This preliminary action ensures uniform powder arrangement and prevents clumping or pre-compaction that would otherwise occur during roller 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
This approach reduces production costs and enhances process reliability by ensuring consistent and even electrode material application, preventing pre-compaction and maintaining the integrity of the roller drive system.
Implementation Method 1
The sieve can be made to vibrate by means of an exciter, such as an ultrasonic or an electrical exciter. Alternatively and/or in addition to the vibrationally excited sieve described above, the transport chute can also be made to vibrate by means of such an exciter.
Implementation Method 2
The sieve can be made to vibrate by means of an exciter, such as an ultrasonic or an electrical exciter.
Implementation Method 3
the powdered output component can be discharged directly into the roller gap feed section under the effect of gravity
Implementation Method 4
compacted into an electrode material film under pressure and shear
Implementation Method 5
compacted into an electrode material film under pressure and shear
Data Source
AI summary
A method for the production of an electrode for a battery cell, with a coating process in which a current collector foil is coated with electrode material by means of a discharge system. The discharge system has a pair of rollers with rotating calender rollers spaced from each other by a roller gap. A powdered output component of the electrode material in the dry state is filled into a roller gap feed section and compacted in the roller gap under pressure and shear to form an electrode material film, which is applied to the current collector foil. The discharge system ensures a temporally and spatially constant and/or adjustable powder dosing into the roller gap.