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CN-122025509-A - Method for producing dry electrodes from electrode mixtures

CN122025509ACN 122025509 ACN122025509 ACN 122025509ACN-122025509-A

Abstract

The present application relates to a method of manufacturing a dry electrode from an electrode mixture. The application relates to a method for producing dry electrodes from electrode mixtures produced in a mixing and/or conditioning process, in which method the electrode mixture is supplied to a calender and calendered into a web, wherein the edge strips or excess material of the web are subsequently separated to ensure a uniform width of the web, characterized in that the separated edge strips or excess material is supplied to a comminuting device which divides the separated edge strips into smaller strip sections which are supplied to the mixing and/or conditioning process for producing a further electrode mixture.

Inventors

  • Stephen Gael

Assignees

  • 德国古斯塔夫·爱立许机械制造有限公司

Dates

Publication Date
20260512
Application Date
20250307
Priority Date
20241111

Claims (10)

  1. 1. A method for producing dry electrodes from electrode mixtures produced in a mixing and/or conditioning process, in which method the electrode mixture is supplied to a calender and calendered into a web, wherein subsequently edge strips or excess material of the web are separated to ensure a uniform width of the web, It is characterized in that the method comprises the steps of, The separated edge strips or excess material are supplied to a comminution device which divides the separated edge strips into smaller strips which are supplied to the mixing process and/or the modulation process for the preparation of further electrode mixtures.
  2. 2. The method according to claim 1, characterized in that a venturi nozzle, a batch-type pulverizing mixer, a continuous-type pulverizing mixer, a granulator, a grinder or a blade rotor is used as the pulverizing device.
  3. 3. Method according to claim 1 or 2, characterized in that for the preparation and modulation of the electrode mixture consisting of active material, optional additives and binders, a method is applied comprising the steps of: 1) The electrode mixture is prepared in a mixing vessel, wherein the mixture is heated to a temperature T H during preparation, wherein T H >45 ℃.
  4. 4. A method according to claim 3, characterized in that the preparation process and the modulation process after step 1) comprise the following steps: 2) Cooling the electrode mixture in the mixing vessel to at least Δt=5 ℃, preferably to a temperature T MAX <35 ℃, but not lower than a withdrawal temperature T E >24 ℃, 3) Withdrawing the electrode mixture having the withdrawal temperature, and supplying the electrode mixture to a cooling device, 4) Cooling the electrode mixture after step 2) by means of the cooling device to a temperature T K <19 ℃.
  5. 5. Method according to claim 4, characterized in that a transfer line of a pneumatic transfer device for removing the electrode mixture from the mixing vessel is provided as cooling device in step 3) and in step 4), which transfer line is operated with a gas, preferably having a temperature T G <19 ℃, wherein dry ice or liquid gas is preferably introduced into the mixing vessel in step 2), between step 2) and step 3) and/or during step 3), and the gas produced by sublimation or evaporation is led into the transfer line.
  6. 6. Method according to claim 4 or 5, characterized in that the electrode mixture after step 2) is transferred into a buffer container, wherein preferably the buffer container is temperature-adjustable and is used as cooling means in step 3) and step 4), wherein the buffer container is preferably implemented with double walls, wherein a cooling fluid can flow between the two walls, and/or the buffer container has an insulating means, wherein particularly preferably the electrode mixture moves in the buffer container.
  7. 7. Method according to any of claims 3 to 6, characterized in that the electrode mixture after step 1), preferably after step 3), is applied to a sieving device and only undersize is used as modulated electrode mixture, wherein preferably the mesh width of the sieving device is less than 10mm, particularly preferably less than 5mm, most preferably less than 2mm.
  8. 8. The method of claim 7, wherein oversize is directed into the mixing vessel, the cooling mixer, the buffer vessel, a comminution device, or the transfer line.
  9. 9. Method according to claim 7, characterized in that a friction screening device or particularly preferably a vortex screening device is used as screening device, wherein preferably the use is made in such a way that no oversize remains.
  10. 10. A method according to any of the preceding claims, characterized in that the separated edge strips or excess material are led into the mixing vessel, the cooling mixer, the buffer vessel or the transfer line.

Description

Method for producing dry electrodes from electrode mixtures The present invention relates to a method for manufacturing a dry electrode from an electrode mixture prepared in a mixing process and/or a brewing process, in which method the electrode mixture is supplied to a calender and calendered into a web, wherein subsequently the edge strips or excess material of the web are separated to ensure a uniform width of the web. Calenders for producing electrodes from dry electrode mixtures are generally composed of a plurality of mutually matched components which enable precise compaction and shaping of the electrode mixture. The basic structure of such calenders generally comprises the following main components: 1. The core component of the calender is two parallel rollers which rotate in opposite directions at the same or different speeds. The rollers are made of a high strength material and can generally be heated to improve the processability of the electrode mixture. The roller surface may be smooth or textured to achieve the desired electrode surface structure. 2. Roll gap-the distance between the two rolls (i.e. the so-called calender gap or roll gap) is precisely adjustable and determines the thickness of the electrode produced. Accurate control of the gap is critical to ensure the desired electrode uniformity and electrode thickness. 3. Supply unit electrode mixture is continuously introduced into the roll gap via the supply unit. The unit may include a conveyor system (e.g., a conveyor belt or hopper) to ensure a uniform and controllable supply of material. 4. Receiving unit after calendaring, the finally formed electrode is transported further through the receiving unit. This may be, for example, a conveyor belt or another rotating roller, which transfers the electrode to the next process step. 5. Edge cutter to trim the edge of the electrode film to a precise width, the calender may be equipped with an edge cutter that removes material from the sides, thereby adjusting the electrode geometry. 6. Lamination unit-finally, the electrode film formed still needs to be laminated to the discharge foil. For this purpose, the electrode film and the discharge foil are guided between a pair of rotating rollers and the electrode film is pressed onto the discharge foil. In some methods of manufacturing dry electrodes, the film formation and lamination onto the discharge foil takes place directly in the first roll gap below the supply unit. By precisely controlling the pressure, temperature and gap width, the calender produces a uniform electrode film having a smooth surface and defined thickness suitable for further processing in the battery cell. In recent years, battery technology, in particular lithium ion technology, has become a focus of attention, as this technology is critical for the function of, for example, fully electrically driven vehicles, but also for stationary power storages. The low cost of manufacturing a high capacity durable battery is a prerequisite for acceptance of all-electric drive vehicles. Currently, lithium ion batteries are mainly used. In this category, there are several specific battery chemistries that predominate, with the most widely used cathode materials being as follows: nickel Manganese Cobalt (NMC) electrode mixtures-these cells use mixtures consisting of nickel, manganese and cobalt. Nickel provides a high energy density, manganese provides thermal stability, and cobalt is responsible for stabilizing the structure. Nickel Cobalt Aluminium (NCA) electrode mixtures containing nickel, cobalt and aluminium in the cathode. The aluminum content stabilizes the structure and increases the service life, while nickel maximizes the energy density. Lithium iron phosphate (LFP) electrode mixtures in which lithium iron phosphate is used as cathode material in such cobalt-free battery chemistries, which have lower energy densities but provide longer service life and better thermal stability. The anode is typically composed of graphite or a silicon-graphite mixture. In all of these types, the electrode mixture is prepared using a polymeric binder (partially with a conductive additive as well), applied to a discharge foil (Ableitfolie), and calendered during or after this to optimize the structural integrity and density of the electrode. In addition, there are some advances that may play a relevant role in the future. In addition to the lower cost but less performing and cobalt-free sodium ion battery chemistries, all-solid state batteries with solid state electrolytes are being actively developed. Theoretically, this technique provides a higher energy density than conventional lithium ion batteries, and also provides higher safety since the electrolyte is solid. The fabrication of all of these cells is expected to continue to require calendaring of the electrodes, which can present various challenges to the calendaring process. In summary, calendaring of electrode mixtures will also play a