CN-122025507-A - Method for producing and preparing electrode mixtures and method for producing dry electrodes from electrode mixtures

Abstract

The present application relates to a method of preparing and modulating an electrode mixture and a method of manufacturing a dry electrode from an electrode mixture. The application relates to a method for producing and preparing an electrode mixture from an active material, optionally additives and binders, comprising the steps of 1) producing the electrode mixture in a mixing vessel of a mixer, wherein the mixture is heated to a temperature T H during production, wherein T H >45 ℃, 2) removing the electrode mixture from the mixing vessel, 3) applying the electrode mixture to a screening device, which separates the electrode mixture into undersize and oversize, and 4) using the undersize as the prepared 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 preparing and conditioning an electrode mixture comprised of an active material, optional additives and a binder, the method comprising the steps of: 1) Preparing the electrode mixture in a mixing vessel of a mixer, wherein the mixture is heated to a temperature T H during the preparation, wherein T H >45 ℃, 2) Withdrawing the electrode mixture from the mixing vessel, 3) Applying the electrode mixture to a sieving device, the sieving device separating the electrode mixture into undersize and oversize, and 4) The undersize is used as a modulated electrode mixture.
2. 2. A method according to claim 1, characterized in that the mesh width of the screening device is less than 10mm, particularly preferably less than 5mm, most preferably less than 2mm.
3. 3. A method according to claim 1 or 2, characterized in that a friction screening device or a vortex screening device is used as screening device.
4. 4. A method according to any one of the preceding claims, wherein the screening device is used such that no oversize remains.
5. 5. The method according to any of the preceding claims, characterized in that after step 1) the following steps are performed: 1a) Cooling the electrode mixture in the container to at least Δt=5 ℃, preferably to a temperature T MAX <35 ℃, but not lower than a withdrawal temperature T E >24 ℃, And after step 2) the following steps are performed: 2a) The electrode mixture is supplied to a cooling device, 2B) Cooling the electrode mixture after step 2 a) by means of the cooling device to a temperature T K <19 ℃.
6. 6. Method according to claim 5, characterized in that a transfer line of a pneumatic transfer device for removing the electrode mixture from the mixing vessel is provided as a cooling device in step 2 a) and in step 2 b), 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 1 a), between step 1 a) and step 2 b) and/or during step 2 b), and the gas produced by sublimation or evaporation is led into the transfer line.
7. 7. The method according to any one of claims 1 to 4, characterized in that the following steps are performed after step 2) and before step 3): 2a1) Transferring the electrode mixture into a cooling mixer having a cooling vessel, the walls of which are preferably cooled, 2A2) Cooling the electrode mixture in the cooling vessel to a withdrawal temperature T E , preferably < 35C, 2A3) The electrode mixture is removed from the cooling vessel.
8. 8. Method according to claim 5, 6 or 7, characterized in that the electrode mixture after step 2) or after step 2a 3) if present and before step 3) and step 4) is transferred into a buffer container, wherein preferably the buffer container is temperature-adjustable and is used as cooling device in step 2 a) and step 2 b), 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 insulation device, wherein particularly preferably the electrode mixture moves in the buffer container.
9. 9. A method of manufacturing a dry electrode from an electrode mixture prepared by means of the method according to any of the preceding claims, characterized in that 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, and the separated edge strips or excess material is led into the container, the cooling container, the buffer container or the transfer line.
10. 10. A method according to claim 9, characterized in that a comminuting device is provided which separates the separated edge strip into smaller strip sections or finer bulk material.

Description

Method for producing and preparing electrode mixtures and method for producing dry electrodes from electrode mixtures The present invention relates to a method of preparing and conditioning a dry electrode mixture. The invention also relates to a method for producing dry electrodes from these electrode mixtures. 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 an important role in future battery technology, as calendaring optimizes the density, uniformity and mechanical properties of the electrodes. However, the specific materials used depend on advances in materials science and the requirements of electric vehicles. Typical lithium ion battery electrodes have copper foil serving as an anode and aluminum foil serving as a cathode. These foils are typically coated on both sides with an active material and also with additives at least for the purpose of manufacturing the cathode. High demands are placed on the electrodes in order to be able to produce reliable high-capacity lithium ion batteries. The electrode layer needs to have a defined constant thickness and a defined pore structure into which electrolyte can enter in order to be able to transport lithium ions to each particle of the active material. In an ideal case, the active material needs to be impregnated with the electrolyte as large an area as possible. Furthermore, the active material particles need to be electrically connected to the metal foil (i.e., to the copper foil or aluminum foil in the example) to ensure that electrons are transported to and from each active material particle. In addition, the active material particles need to be bonded to each other and to the metal foil, for which purpose a binder material is used. Finally, the layer thickness should be formed as uniformly as possible over the width and length. In order to manufacture these layers for dry electrodes, the raw materials (i.e. active material, binder and optional additives) need to be mixed with each other and treated into a so-called structured mixture. The electrode mixture for the dry electrode is prepared with little or usually no solvent. In this case, however, when the components are mixed, a more intensive treatment is required in order to convert the polymer binder used, which is no longer soluble in solvents as usual, into a processable and bondable state. Particularly when PTFE or PVDF is used as the binder, the mixture typically needs to be processed in successive steps at different temperatures. When PTFE is used, the mixture is fibrillated (fibrillieren) by temperature activation at a temperature >30 ℃ and the introduction of shear energy (SCHERENERGIE). The nano-and micro-sized polymer fibers produced during fibrillation can produce substance