METHOD AND DEVICE FOR PRODUCING A SOLID BODY SEPARATOR FOR A BATTERY CELL

Description

[0001] The invention relates to a method and a device for producing a solid-state separator for a battery cell according to the preamble of the independent patent claims.

[0002] Rechargeable electrochemical storage systems are becoming increasingly important for many areas of daily life. High-capacity energy storage devices, such as lithium-ion (Li-ion) batteries and capacitors, are used in a growing number of applications, including portable electronics such as mobile phones and laptops, medical and laboratory equipment, grid-connected large-scale energy storage for storing renewable energy, uninterruptible power supplies (UPS), and electric vehicles. Due to the rapid market development of electric vehicles and grid-connected energy storage, high-performance, low-cost lithium-ion batteries are currently one of the most promising options for large-scale energy storage.

[0003] In each of these applications, the charge / discharge time and capacity of energy storage devices are the decisive parameters. Furthermore, the size, weight, and / or cost of such energy storage devices are also important parameters. Furthermore, low internal resistance is required for high performance. The lower the resistance, the fewer limitations the energy storage device faces in delivering electrical energy. For example, in the case of a battery, internal resistance affects performance by reducing the total amount of useful energy stored by the battery and the battery's ability to deliver high current. Furthermore, Li-ion batteries are said to best achieve the desired capacity and cycling.However, Li-ion batteries in their current form often lack the energy capacity and number of charge / discharge cycles for these growing applications.

[0004] A lithium-ion battery generally consists of a separator, a cathode, and an anode. Currently, the electrodes are manufactured by dispersing fine powders of an active battery electrode material, a conductive agent, and a binder in a suitable solvent. The dispersion can be applied to a current collector, such as a copper or aluminum metal foil, and then dried at elevated temperature to remove the solvent. The cathode and anode sheets are then stacked or rolled, with the separator separating the cathode and anode to form a battery.

[0005] Researchers around the world are working on developing the next generation of batteries for electromobility. The most promising are solid-state batteries, which are already nearing series production and offer numerous advantages for use in electric cars. Compared to conventional lithium-ion batteries, solid-state batteries offer a higher energy density, allowing the batteries to be made smaller or more powerful within the same size, offer even greater safety, and can be charged faster.

[0006] Ideally, solid-state batteries don't require a cooling circuit, as is necessary for lithium-ion batteries with liquid electrolyte. This saves space and weight. They can achieve significantly more charging cycles, don't self-decompose or overheat, and offer more homogeneous current distribution. They can also be built with very thin electrolyte layers that are also flexible.

[0007] The production of such solid-state batteries is complex and characterized by a multitude of precise assembly steps in the area of ​​cell production. This complex production process significantly increases waste and, moreover, reduces the robustness of the manufacturing process and the safety of the manufactured solid-state battery cell. Therefore, simplifying production can produce a more environmentally friendly, economical, and safe product. The manufacture of solid-state separators, in particular, is time-consuming, energy-intensive, and therefore expensive. Such solid-state separators are typically manufactured from individual sheets, with a carrier material coated with a slurry or powder. The composite of carrier material and coating is then dried, and the carrier material is removed, creating a green compact of the solid-state separator.This green compact is then further processed into the finished solid-state separator in a sintering process. Since the solid-state separator is manufactured from individual sheets, increased handling effort is required during coating, drying, and sintering.

[0008] CN 112 968 217 A1 discloses a method for attaching a positive electrode material to a solid electrolyte. After the positive electrode material has been applied to an inorganic solid electrolyte, a selective laser melting / sintering process is performed on the inorganic solid electrolyte. Rapid annealing causes the positive electrode material and the solid electrolyte to form close physical contact, allowing a compact, positive electrode material stably bonded to the solid electrolyte to be obtained within a very short time.

[0009] DE 10 2018 130 962 A1 discloses a method for providing a particulate material from an at least substantially metallic and / or ceramic starting material, which comprises the following steps: a) producing the particulate material from the starting material by evaporating the starting material by introducing energy into the starting material and subsequently at least partially condensing the evaporated starting material; b) collecting the particulate material in at least one receiving and / or transport device; c) receiving the particulate material in the receiving and / or transport device such that it can be used for a subsequent process; and d) providing the particulate material for the subsequent process.

[0010] DE 10 2012 217 309 A1 discloses a layered composite for a battery cell comprising a layer of oxygen-ion-conducting solid electrolyte and a needle- or hillock-like structure made of a ceramic, oxygen-ion- and electron-conducting transfer layer. The needle- or hillock-like structure is located on the layer of oxygen-ion-conducting solid electrolyte. The needle- or hillock-like structure is covered by a layer of storage electrodes.

[0011] The invention is based on the object of simplifying the production of a solid-state separator for a battery cell and increasing the energy efficiency of production as well as the production speed.

[0012] The object is achieved by a method for producing a solid separator for a battery cell, which comprises the following: Feeding a substrate, preferably an electrically conductive substrate, applying a slurry of a ceramic solid separator, comprising a solid electrolyte, a polymer binder and a solvent, to the substrate, drying the substrate coated with the slurry, whereby a dried coating is formed, and sintering the dried coating of the substrate, whereby the coating is heated to a process temperature TP for sintering the coating by coupling in high-energy radiation from a surface emitter.

[0013] A slip is a liquid, pasty to viscous solvent-mineral mixture used to manufacture ceramic products. In the context of this patent application, drying refers to the complete or partial removal of liquid from a moist slip by evaporation or vaporization. Sintering in this context refers to the heating of a fine-grained ceramic material. However, the temperatures of the sintering process remain below the melting temperature of the main components, so that the shape of the workpiece is retained except for process-related shrinkage. A surface emitter in this context refers to a laser diode in which the light is emitted perpendicular to the plane of a semiconductor chip, which contrasts with the beam-like emission of a conventional laser.

[0014] The process according to the invention enables a particularly simple, rapid, and cost-effective production of a solid-state separator. The slurry is intensively and homogeneously dried over the entire surface of the substrate and then sintered, resulting in a particularly uniform structure of the solid-state separator. The solid-state separator exhibits high lithium-ion conductivity and is also referred to as a solid electrolyte.

[0015] The additional features listed in the dependent claims enable advantageous improvements and further developments of the method for producing a separator for a battery cell specified in the independent claim.

[0016] In a preferred embodiment of the invention, the surface emitter comprises a VCSEL matrix. A VCSEL matrix enables uniform coupling of energy into a surface, in this case the coating of the substrate, in order to achieve a uniformly high heat input into the coating and to dry and sinter it. By controlling the power of individual or interconnected VCSEL matrix units, the heating can be adjusted statically or dynamically to such an extent that a temporally and spatially homogeneous and stable temperature topography is achieved on the surface of the substrate coating.

[0017] In a further preferred embodiment of the invention, the substrate is supplied as a strip or foil material. Supplying a strip or foil material enables particularly simple and cost-effective production of the separator. In particular, the processing of the substrate and the slurry is possible in a continuous process, which can increase the production speed of the separator, since manual handling for coating the substrate, loading a drying furnace, or feeding a sintering furnace can be eliminated.

[0018] In a preferred embodiment of the invention, both surfaces of the substrate are coated with a slurry, forming a ceramic solid separator on both surfaces of the substrate. Coating on both sides is particularly advantageous because it allows two layers of a solid separator to be produced simultaneously. This increases the process speed and further improves productivity in the production of the solid separator.

[0019] According to an advantageous embodiment of the method, the solid separator is bonded to the substrate. Such a bond enables the corresponding formation of a current collector on the anode, particularly in solid-state batteries where the anode is formed in situ by lithium deposition during the charging process. The solid separator functions as a solid electrolyte, and the substrate provides the electrical connection to the anode.

[0020] It is particularly preferred if the substrate with the sintered coating is briefly heated above a melting temperature after the sintering process, whereby the substrate at least partially clasps the solid separator and / or the solid separator is at least partially enclosed by the molten substrate. Brief heating above the melting temperature can improve the bond between the solid separator and the substrate. In particular, brief melting can reduce the interfacial resistances between a metallic, electrically conductive substrate and the solid separator. In addition, brief melting can reduce residual stresses in the substrate and / or the sintered coating in order to improve the durability of the separator and reduce the risk of mechanical or thermal damage to the separator during subsequent operation of the battery.Furthermore, by partially melting the substrate, a mechanical bond can be formed between the solid separator and the substrate. Alternatively or additionally, the solid separator can be at least partially enclosed by the melted substrate. This allows a particularly strong connection to be formed between the substrate and the solid separator.

[0021] In an advantageous embodiment of the method, a drying process, a sintering process, and / or a cooling process of the solid-state separator are carried out in a process atmosphere. A process atmosphere can prevent undesirable chemical side reactions during the drying, sintering, and / or cooling of the solid-state separator. This can increase the energy density of the solid-state battery and reduce its susceptibility to mechanical damage, particularly breakage of the solid-state separator.

[0022] It is particularly preferred if, to dry the coated substrate, the substrate is inductively heated and dry air and / or a process gas are additionally supplied. In this case, an atmosphere is created in the process chamber which is largely free of water vapor in order to avoid side reactions during the drying and sintering of the slip. An atmosphere which is largely free of water is understood to be an atmosphere with a dew point of less than -20°C, preferably less than -40°C, particularly preferably less than -65°C. Alternatively or additionally, the atmosphere can also comprise process gases, in particular inert gases such as nitrogen, which prevent a reaction of water vapor with the slip during the tempering process. Alternatively, reactive process gases can also be used which establish a diffusion equilibrium and prevent the lithium from diffusing out of the slip.

[0023] In an advantageous embodiment of the method, the coated substrate is dried using a surface emitter. By drying and sintering the substrate with surface emitters, the manufacturing process can be controlled particularly easily. Alternatively, drying can also be carried out using another known technology, in particular a drying oven.

[0024] According to an advantageous embodiment of the method, drying takes place at a steady-state temperature below the sintering temperature of the slurry. This allows the porosity of a green body, i.e., the coated substrate before the sintering process, to be adjusted during drying in order to achieve the desired mechanical and electrochemical properties.

[0025] In a preferred embodiment of the method, the thickness of the dried coating is in a range from 0.1 µm to 50 µm, preferably from 1 µm to 20 µm, particularly preferably from 2 µm to 10 µm. This allows for the formation of a thin, yet mechanically sufficiently stable and electrically sufficiently insulating separator layer. A thin separator layer enables denser stacking of the cell stack within the same installation space, thereby increasing the power density of the solid-state battery.

[0026] In a further advantageous embodiment of the method, it is provided that a wavelength of the radiation of the surface emitter is in the range from 10 nm to 20,000 nm, preferably in the range from 10 nm to 1,800 nm, particularly preferably from 100 nm to 1,600 nm, in particular in the range from 300 nm to 1,500 nm.

[0027] The wavelength depends on the type of surface emitter and the solid electrolyte. A wavelength of 10 nm to 1800 nm is particularly suitable for drying the slurry on the substrate and sintering the dried coating. With a surface emitter at this wavelength, the dried coating absorbs the energy particularly well, allowing the energy from the surface emitter to be coupled particularly efficiently into the substrate coating. This enables a particularly efficient sintering process.

[0028] In a preferred embodiment of the invention, the metallic, electrically conductive substrate is a copper foil, a nickel foil, or a composite foil composed of two or more metallic layers, in particular a nickel-coated copper foil. Copper and nickel foils are particularly suitable because they have a melting point that is higher than the sintering temperature of the slurry or the dried coating of the substrate. This prevents the substrate from melting during the sintering process and prevents the dried coating from being adequately supported by the substrate.

[0029] Since copper has higher thermal and electrical conductivity than nickel, copper is generally preferred as an electrically conductive substrate. However, due to the different morphologies of nickel and copper, it may be advantageous to coat a copper foil with nickel to combine the advantages of both materials.

[0030] In a preferred embodiment of the method, the slurry of the solid separator is a crystalline electrolyte with a high conductivity for lithium ions.

[0031] It is particularly preferred if the slurry of the solids separator comprises an oxidic, ion-conducting material, preferably an oxidic, lithium-ion-conducting ceramic or glass-ceramic, in particular lithium lanthanum zirconium oxide (LLZO), a lithium aluminum titanium phosphate, a lithium lanthanum titanate, or a derivative. Compared to elemental lithium, lithium lanthanum zirconium oxide offers the advantage of being particularly chemically and mechanically stable.

[0032] In a preferred embodiment of the method, the solid separator has a NASICON structure. Suitable lithium-analogous structures of NASICON include, in particular, lithium phosphates of the formula LiM 2 (PO 4 ) 3 , where M stands for a base element selected from the group Ti, Ge, Zr, Hf or Sn. To increase the ionic conductivity, the lithium phosphates can be doped, with Al, Cr, Ga, Fe, Sc, In, Lu, Y and La preferably serving as dopant. Particular preference is given to LiZr 2 (PO 4 ) 3 (LZP) doped with La, Ti or Al; LiTi 2 (PO 4 ) 3 (LTP); Li 1+x Al x Ti 2-x (PO 4 ) 3 with x = 0.3 - 0.5 (LATP) Li 1+x Al x Ge 2- x (PO 4 ) 3 with x = 0.4 - 0.5 (LAGP) and Li 1.4 Al 0.4 Ge 0.2 Ti 1.6 (PO 4 ) 3 LAGTP.

[0033] In a further preferred embodiment of the method, the solid separator has a LISICON structure. LISICON is an acronym for Lithium Super Ionic Conductor and originally referred to a family of minerals with the chemical formula Li 2+2x Zn 1-x GeO 4 . Solid separators with a LISICON structure also enable additional lithium absorption and can make this lithium available for function in the battery cell of a solid-state battery.

[0034] In a further preferred embodiment of the method, the solid separator has a garnet structure. Structurally, garnets are orthosilicates of the general composition X 3 Y 2 (SiO 4 ) 3 , which crystallize in the cubic crystal system, where X and Y represent eight- and six-coordinate cation sites, respectively. The individual SiO 4 tetrahedra are connected to one another by ionic bonds via the interstitial B cations. Garnet-like compounds with an excess of lithium are good lithium ion conductors. Particularly suitable examples of ion conductors with a garnet-like structure are lithium lanthanum zirconium oxide Li 7 La 3 Zr 2 O 12 (LLZO) and lithium lanthanum zirconium titanate Li 6.6 La 3 Zr 1.6 Ta 0.4 O 12 .

[0035] In a further preferred embodiment of the method, the solid separator has an argyrodite structure. Argyrodite is a mineral with an orthorhombic crystal system of the chemical composition Ag 8 GeS 6 . The term is used here for lithium ion conductors that have a comparable crystal system. Examples include Li 7-x ZCh 6-x X x where x = 0 to 1, Z = P or As, Ch = S or Se and X = Cl, Br or I. Particularly preferred are the Li argyrodites Li 6 PS 5 X (X = Cl, Br and I), Li 7 PS 6 and Li 7 PSe 6 and Li 6.6 P 0.4 Ge 0.6 S 5 I. Additional lithium can also be absorbed into this crystal system and can then be released to deposit an anode when a battery cell is charged with such an electrolyte.

[0036] In a further preferred embodiment of the method, the solid separator has a perovskite structure. A particularly suitable perovskite is lithium lanthanum titanate (LLTO), with vacancies in the perovskite structure enabling the high conductivity.

[0037] Alternatively, it is advantageous for the solid electrolyte to be a sulfidic solid electrolyte. High ionic conductivities can also be achieved with sulfidic solid electrolytes with a structure different from the aforementioned types. One example is the ionic conductor Li 10 GeP 2 S 12 (LGPS) and ionic conductors derived from it with an LGPS structure, such as Li 10 SiP 2 S 12 . Furthermore, minerals structurally comparable to LISICON with a different chemical composition can be used, in which oxygen is replaced by sulfur (thio-LISICON). Suitable sulfur-based solid electrolytes include, for example, Li 2 SP 2 S 5 -X systems (where X = SiS 2 , GeS 2 , LiIl, P 2 S 3 , P 2 Se 5 , P 2 O 5 or without additives).

[0038] Another example of a sulfur-based solid electrolyte is β-Li 3 PS 4 . Binary sulfide glasses, such as Li 2 SP 2 S 5 , Li 2 S-SiS 2 , and Li 2 S-GeS 2 , are also particularly suitable for use as solid electrolytes. Examples include 77.5Li 2 S-22.5P 2 S 5 , LiI-Li 2 SP 2 S 5 , 80Li 2 S-20P 2 S 5 , and 70Li 2 S-29P 2 S 5 -1P 2 O 5 .

[0039] In an advantageous embodiment of the method, the substrate with the sintered coating is removed as a strip material. This enables particularly simple process control during coating, drying, and sintering, whereby the substrate with the sintered coating can be wound onto a receiving device, in particular a roll, a sleeve, or a drum, in order to be easily fed to a subsequent production step in the battery manufacture. Alternatively, the sintered substrate can also be cut into the shape of the desired separators after the sintering process and fed to the next process step in the battery manufacture as a stackable piece.

[0040] A further aspect of the invention relates to a device for producing such a solid separator for a battery cell. The device comprises means for supplying a substrate, in particular an electrically conductive substrate, means for applying a slurry of a solid separator to the substrate, means for drying the substrate coated with the slurry, thereby forming a dried coating, and means for sintering the dried coating of the substrate. The sintering means comprise at least one surface emitter for heating the dried coating to a process temperature TP for sintering the coating.

[0041] In an advantageous further development of the device, the means for drying and / or sintering the coating on the substrate comprise several surface emitters connected in series. This allows for particularly simple control of the temperature in the coating. Furthermore, in a continuous process, it may be necessary to use several surface emitters to heat the dried coating sufficiently long to complete the sintering process.

[0042] A further improvement of the device provides that the means for drying and / or sintering the coating of the substrate comprise a plurality of surface emitters, with at least two of the surface emitters being arranged on different sides of the substrate. This enables a uniform heat input into the substrate. This enables very uniform drying, resulting in a substantially homogeneous structure of the coated and dried substrate. Furthermore, heating on both sides enables migration of the binding agent from the center of the slurry to the surface, which can improve the electrochemical properties of the separator.

[0043] In an advantageous embodiment of the device, the means for applying the slurry to the substrate comprise a slotted nozzle. A slotted nozzle enables particularly gentle and force-free application of the slurry to the substrate. This reduces the stress on the substrate.

[0044] Alternatively or additionally, it is advantageously provided that the means for applying the slurry comprise a roller for coating the substrate. Applying the slurry to the substrate with a roller enables coating of the substrate in a particularly simple and cost-effective manner.

[0045] It is particularly preferred if the application means comprise two counter-rotating coating rollers that apply a slurry to at least one surface of the substrate, preferably to two surfaces of the substrate. Two counter-rotating rollers enable a particularly uniform application of a thin layer of the slurry to the substrate.

[0046] The various embodiments of the invention mentioned in this application can be advantageously combined with one another, unless otherwise stated in the individual case.

[0047] The invention is explained below in exemplary embodiments with reference to the accompanying drawings. They show: Figure 1 shows a preferred embodiment of an apparatus according to the invention for producing a solid separator for a battery cell; Figure 2 shows a further preferred embodiment of an apparatus according to the invention for producing a solid separator for a battery cell; Figure 3 shows a substrate coated with a solid separator for drying and sintering by a surface emitter; and Figure 4 shows a flow diagram for carrying out an inventive method for producing a solid separator for a battery cell.

[0048] Figure 1shows a device 10 for producing a solid separator 80 for a battery cell. The device 10 comprises means 12, 14 for feeding a metallic, electrically conductive substrate 30, which comprises a first receiving device 12, in particular a roller, a mandrel on a clamping sleeve, or a drum, on which the metallic, electrically conductive substrate 30 is wound in the form of a strip or foil material 36 and is fed to the other components of the device 10. The feeding means further comprise a first deflection roller 14, with which the metallic, electrically conductive substrate is deflected and fed to a heating zone 22 for drying and subsequent sintering.

[0049] The device 10 further comprises means 20 for applying a slurry 32 of a solid separator to the metallic, electrically conductive substrate 30. For this purpose, a first application unit 20 is provided for applying a slurry 32 of a solid separator to a first side of the metallic, electrically conductive substrate 30. The application unit 20 has a pair of counter-rotating rollers 26, which coat the substrate 30 on one surface with the slurry 32. The slurry 32 of the solid separator comprises a solvent, a solid electrolyte, and a polymer binder. The substrate 30 is, in particular, a copper foil, a nickel foil, or a composite foil comprising a copper foil and / or a nickel foil as well as additional metallic layers. As an alternative to the counter-rotating rollers 26, the slurry 32 can also be applied to the substrate 30 in another manner, in particular through one or more slotted nozzles.

[0050] The device 10 further comprises means 40, 42, 44 for drying the coated substrate 34. The means comprise a drying unit which comprises one or more surface emitters 40, 42, 44. The drying unit can additionally comprise one or preferably several process gas nozzles 52, 54, with which dry air or a process gas is blown into the drying unit. In this exemplary embodiment, the surface emitters 40, 42, 44 are arranged on the side of the coated substrate 34 facing the slurry 32. The surface emitters 40, 42, 44 each comprise a laser unit 64, which forms a VCSEL matrix 66 and thus enables coupling of high-energy laser radiation 68 into the coating of the substrate 30.

[0051] The device 10 further comprises means 46, 48, 50 for sintering the dried coating 82 of the substrate 30, in particular a sintering unit, which adjoins the means 40, 42, 44 for drying the coated substrate 34 in the process direction. The sintering means 46, 48, 50 comprise, in particular, further surface emitters 46, 48, 50, which are also arranged on the side of the substrate 30 facing the coating 82.

[0052] The sintering means 46, 48, 50 are particularly configured to further heat the temperature of the dried, coated substrate 34 from a steady-state drying temperature TB to a sintering temperature TS of preferably 1000°C to 1200°C. Additional process gas nozzles 56, 58 can be arranged in the sintering unit to also supply dry air or a process gas to the sintering unit to optimize the sintering process.The sintering means 46, 48, 50 can further be configured to briefly heat the substrate 30 with the sintered coating 38 after sintering to a temperature TL above the sintering temperature, in particular to a temperature of more than 1200°C, in order to briefly cause melting at the connection point between the metallic, electrically conductive substrate 30 and the sintered coating 38, whereby residual stresses in the sintered substrate 38 can be reduced and the contact resistance between the metallic, electrically conductive substrate 30 and the solid separator 80 can be reduced. The sintering means 46, 48, 50 are also designed as surface emitters 46, 48, 50 and each comprise a laser unit 64 which forms a VCSEL matrix 66 and thus enables coupling of a high-energy laser radiation 68 into the dried coating 82 of the substrate 30 in order to sinter this coating 82.

[0053] The drying means 40, 42, 44 and the sintering means 46, 48, 50 can be arranged in a common heating zone 22, which forms a process chamber 60 flooded with a process gas and in which a process atmosphere 62 is formed by the process gas. Furthermore, a support roller 24 can be arranged in the heating zone 22 to support the substrate 30 during drying and / or sintering.

[0054] The device 10 further comprises a second deflection roller 16, with which the solid separator 80 is guided out of the heating zone 22 and fed to a second receiving device 18, in particular a further roller, a drum or a sleeve on a mandrel, on which the substrate 30 with the sintered coating 38 can be rolled up for further processing.

[0055] The device 10 further comprises a control unit 70 with a memory unit 72 and a computing unit 74. A machine-readable program code 76 for controlling the device and for executing a method according to the invention is stored in the memory unit 72. The control unit 70 is configured to execute a method according to the invention for producing a solids separator 80 using the described device 10 when the machine-readable program code 76 is executed by the computing unit 74.

[0056] In Figure 2 A further embodiment of a device 10 for producing a solid separator 80 is shown. With essentially the same structure as Figure 1In this exemplary embodiment, the substrate 30 is coated on both sides with a slurry 32. For this purpose, the device 10 has means 20, 84 for applying a slurry 32 of a solid separator to the metallic, electrically conductive substrate 30. A first application unit 20 is provided on a first surface of the substrate 30 for applying a slurry 32 of a solid separator to a first side of the metallic, electrically conductive substrate 30. The means 20 for applying a slurry 32 further comprise a second application unit 84 for applying the slurry 32 of the solid separator to a second side of the metallic, electrically conductive substrate 30. The device 10 further comprises means 40, 42, 44, 46, 48, 50, 64, 66 for drying and sintering the coated substrate 34.The surface emitters 40, 42, 44, 46, 48, 50 are preferably arranged on both sides of the coated substrate 34 guided through the drying unit, i.e., above and below the coated substrate 34. Particularly preferably, in the process direction through the drying unit and the sintering unit, surface emitters 40, 42, 44, 46, 48, 50 for heating the coating 82 and process gas nozzles 52, 54, 56, 58 for blowing in dry air or a process gas are arranged alternately on both sides of the coated substrate 34.

[0057] Figure 3shows a substrate 34 coated with a slurry 32 in a drying and subsequent sintering process. Preferably, a metallic, electrically conductive substrate 30, preferably a foil 36, in particular a copper foil or a nickel foil or a composite foil comprising a copper foil and / or a nickel foil as well as additional metallic layers, is coated on at least one side with a slurry 32 of a solid separator. A surface emitter 40, in particular a laser unit 64 with a VSCEL matrix 66 for emitting high-energy laser radiation 68, is arranged on the slurry 32 or a coating 82 formed from the slurry 32 in order to heat the metallic, electrically conductive substrate 30 by the laser radiation 68 and to dry the slurry 32.In this way, the coating 82 on the substrate 30 is dried, which in a subsequent process step is applied by a . Figure 1 or Figure 2 further surface emitters 42, 44, 46, 48, 50 shown are heated and sintered, so that a sintered coating 38 is formed on the substrate 30, which can be integrally connected to the metallic, electrically conductive substrate 30.

[0058] Figure 4shows a flowchart for carrying out a method according to the invention for producing a solid separator 80 for a battery cell. In a first method step <100> A preferably metallic, electrically conductive substrate 30 is fed to a coating process. This is preferably carried out in the form of a strip material, which is unwound from a first receiving device 12, in particular a roll, of the device 10. In a method step <110> A slurry 32 of a solid separator is applied to a first side of the substrate 30 by means of a first application unit 20. Subsequently, in a process step <120> Another slurry 32 of a solid separator is applied to a second side of the substrate 30 using a second application unit 84. The application of the slurry 32 to the two sides of the substrate 30 can also be carried out in parallel.In a simplified embodiment of the method, the substrate 30 can also be coated with a slip on only one side, so that one of the method steps <110> or <120> can be omitted.

[0059] In one process step <130> The substrate 34 coated with the slip 32 is fed to a heating zone 22, which comprises a drying unit and a sintering unit. The drying unit and the sintering unit are preferably arranged together in a common housing, so that the coated substrate 34 is continuously heated, first in a process step <140> by the radiation 68 of the surface emitter 40, 42, 44, 46, 48, 50, 64, 66, the substrate 30 is heated and the coating 82 of the substrate 30 is thereby dried. In a process step following the drying <150> the coated substrate 34 is sintered by heating the substrate 30 and the dried coating 82 of the slurry 32 by the surface emitter(s) 40, 42, 44, 46, 48, 50, 64, 66, so that a mechanically stable sintered coating 38 of the substrate 30 is formed.

[0060] In a further process step <160> The substrate 30 can be briefly heated above a melting temperature, causing melting in the bonding area between the substrate 30 and the sintered coating 38, which can reduce the contact resistance and residual stresses. This can increase both the mechanical strength and the thermal stability of the solid separator 80. List of reference symbols

[0061] 10Device 12First support device 14First pulley 16Second pulley 18Second support device 20First application unit 22Heating zone 24Support roller 26Counter-rotating rollers 28Slot nozzle 30Substrate 32Slip 34Coated substrate 36Foil 38Sintered coating 40first emitter 42second emitter 44third emitter 46fourth emitter 48fifth emitter 50additional emitter 52first process gas nozzle 54second process gas nozzle 56third process gas nozzle 58additional process gas nozzle 60Process chamber 62Process atmosphere 64Laser unit 66VCSEL matrix 68Laser radiation 70Control unit 72Storage unit 74Arithmetic unit 76Machine-readable program code 80Solids separator 82Dried coating 84Second application unit

Claims

1. A method for producing a solid separator (80) for a battery cell, comprising: - supplying a substrate (30), - applying a slurry (32) of a ceramic solid separator, comprising a solid electrolyte, a polymer binder, and a solvent, onto the substrate (30), - drying the substrate (34) coated with the slurry (32), wherein a dried coating (82) is formed, and - sintering the dried coating (82) of the substrate (30), wherein the coating (82) is heated by coupling high-energy radiation (68) from a surface emitter (40, 42, 44, 46, 48, 50, 64, 66) to a process temperature Tp for sintering the coating (82).

2. The method for producing a solid separator (80) for a battery cell according to Claim 1, characterized in that the surface emitter (40, 42, 44, 46, 48, 50) comprises a VCSEL matrix (66).

3. The method for producing a solid separator (80) for a battery cell according to Claim 1 or 2, characterized in that the substrate (30) is supplied as a strip material or foil material (36).

4. The method for producing a solid separator (80) for a battery cell according to any one of the Claims 1 or 3, wherein both surfaces of the substrate (30) are coated with a slurry (32) such that a ceramic solid separator (80) is formed on both surfaces of the substrate.

5. The method for producing a solid separator (80) for a battery cell according to any one of the Claims 1 or 4, wherein the solid separator (80) is integrally connected to the substrate (30).

6. The method for producing a solid separator (80) for a battery cell according to Claim 5, wherein, after the sintering process, the substrate (30) with the sintered coating (38) is briefly heated to above a melting point, whereby the substrate (30) at least partially clasps around the solid separator (80) and / or the solid separator (80) is at least partially enclosed by the melted substrate (30).

7. The method for producing a solid separator (80) for a battery cell according to any one of the Claims 1 to 6, wherein a drying process, a sintering process and / or a cooling process of the solid separator (80) are performed under a process atmosphere.

8. The method for producing a solid separator (80) for a battery cell according to any one of the Claims 1 or 7, wherein the coated substrate (34) is dried by means of a surface emitter (40, 42, 44, 46, 48, 50, 64, 66).

9. The method for producing a solid separator (80) for a battery cell according to any one of the Claims 1 or 8, wherein a coat thickness of the dried coating (82) is in a range of 0.1 µm to 50 µm.

10. The method for producing a solid separator (80) for a battery cell according to any one of the Claims 1 or 9, wherein a wavelength of the radiation (68) of the surface emitter (40, 42, 44, 46, 48, 50, 64, 66) is in the range of 10 nm to 20000 nm.

11. The method for producing a solid separator (80) for a battery cell according to any one of the Claims 1 or 10, wherein the substrate (30) is a copper foil, a nickel foil or a composite foil made of two or more metallic layers.

12. A solid separator (80) for a battery cell, produced with a method according to any one of the Claims 1 to 11.

13. A device for producing a solid separator (80) for a battery cell, comprising - means (12, 14) for supplying a substrate (30), - means for applying a slurry (32) of a solid separator onto the substrate (30), - means (40, 42, 44, 46, 48, 50, 64, 66) for drying the substrate (30) coated with the slurry (32), wherein a dried coating (82) is formed, - means (40, 42, 44, 46, 48, 50, 64, 66) for sintering the dried coating (82) of the substrate (30), wherein the means (40, 42, 44, 46, 48, 50, 64, 66) have at least one surface emitter (40, 42, 44, 46, 48, 50, 64, 66) for heating the dried coating (82) to a process temperature Tp for sintering the coating (82).

14. The device for producing a solid separator (80) for a battery cell according to Claim 13, wherein the means (40, 42, 44, 46, 48, 50, 64, 66) for drying and / or sintering the coating of the substrate (30) comprise multiple sequentially switched surface emitters (40, 42, 44, 46, 48, 50).

15. The device for producing a solid separator (80) for a battery cell according to Claim 13 or 14, wherein the means (40, 42, 44, 46, 48, 50, 64, 66) for drying and / or sintering the coating of the substrate (30) comprise multiple surface emitters (40, 42, 44, 46, 48, 50), wherein at least two of the surface emitters (40, 42, 44, 46, 48, 50) are arranged on different sides of the substrate (30).