Method for manufacturing an all-solid-state battery cell

Abstract

To provide a method for allowing lower-cost production of a solid-state battery cell.SOLUTION: A method for producing a solid-state battery cell (1) comprises: a) providing a starting material for a separator material (2) in the form of a layer (3); and b) at least partially coating the layer (3) with a sublimable coating material (4) so as to form a separator material (2) coated with a coating (5).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an all-solid-state battery cell, and in particular to the manufacture of separator materials for use in the all-solid-state battery cell.

[0002] Batteries, especially lithium-ion batteries, are increasingly being used for automotive drive systems. For example, automobiles have electric machines that drive the automobile, and the electric machines can be driven by electrical energy stored in battery cells. Batteries generally consist of a plurality of battery cells, each of which has a stack of anode plates, cathode plates, and separator plates. At least some of the anode and cathode plates are formed as electrical conductors for conducting electrical current from the cell to consumers located outside the cell. Battery cells with liquid electrolytes or solid electrolytes (all-solid-state batteries) are known.

[0003] The all-solid-state battery cell comprises a particularly hermetically formed casing and at least one stack of overlapping electrodes or layers arranged therein. The casing can be formed as a shape-permanent casing (prismatic cell) or at least partially from an elastically deformable film material (pouch cell). It is also possible to combine both casing types.

[0004] The separator material is used in all-solid-state (ASS) battery cells, which contain exclusively solid components (including semi-solid electrolytes, e.g., polymers), i.e., solid electrolytes. These solid electrolytes are arranged between the electrodes (anode, cathode) as ion-conducting separator materials. These separator materials are usually made of ceramic materials, or alternatively of polymers, glass, or hybrid materials.

[0005] Separators made of ion-conducting solid electrolytes have significant instability, particularly with respect to air moisture and air oxygen. Furthermore, during the sintering process or during the production of, for example, ion-conducting solid electrolytes, a large portion of the ions or lithium evaporates from the material. Both the lithium evaporation and the reaction with air components reduce the ion conductivity or lithium conductivity, and thus the performance of the separator material or separator membrane for solid-state battery cells.

[0006] Furthermore, it is generally intended that the lithium anode be formed in place within the all-solid-state battery cell during the first charge cycle of the battery cell (i.e., during molding), which requires that the separator material have specific surface features to facilitate the necessary deposition.

[0007] Contact of the separator material with atmospheric moisture or atmospheric oxygen has traditionally been prevented by the use of a protective gas atmosphere, but providing and maintaining such a protective gas atmosphere is extremely time-consuming.

[0008] From GB 1 189 222 A1 a method is known for producing electrodes for battery cells, in which a solid electrolyte is produced and coated with an electrode material.

[0009] From WO 2004 / 067259 a manufacturing method for a fuel cell is known.

[0010] The object of the present invention is to at least partially solve the problems mentioned in relation to the prior art, and in particular to propose a method that allows for the production of all-solid-state battery cells at lower costs.

[0011] The solution to this problem is provided by a method having the features of claim 1. Advantageous refinements are the subject of the dependent patent claims. The features individually recited in the patent claims can be combined with one another in a technically significant manner and can be supplemented by details from the context described in the description and / or from the drawings, which in this case represent further variant embodiments of the invention.

[0012] A method for manufacturing an all-solid-state battery cell is proposed, which comprises at least the following steps: a) providing raw materials for a separator material in the form of a layer; b) at least partially coating the layer with a sublimable coating material to form a coated separator material; Includes.

[0013] The (non-final) division of the above-mentioned method steps into a) and b) is merely used to distinguish preferentially and does not impose any order and / or dependency. The frequency of the method steps may also vary. Likewise, it is also possible for the method steps to at least partially overlap in time with one another. Preferably, steps a) and b) are performed in the order described.

[0014] The coated separator material produced in steps a) and b) is intended for use in particular in lithium ion or lithium metal battery cells, and possibly also in sodium or aluminum battery cells.

[0015] The separator materials are used in all-solid-state (ASS) battery cells, which contain exclusively solid components (including semi-solid electrolytes, e.g., polymers), i.e., solid electrolytes. These solid electrolytes are arranged between the electrodes as ion-conducting separator materials and / or are already contained in or mixed with the active material as electrolytes. These separator materials are typically made of ceramic materials, or polymers, glasses, or hybrid materials.

[0016] In particular, between steps a) and b), a further step a1) is provided, in which the layer is sintered after step a), which process step is provided in particular in the case of ceramic separator materials. Step a1) is then followed in particular by step b).

[0017] In particular, lithium ion conducting raw materials for use as separator materials (or as electrolytes in the cathode or anode layers) include at least one of the following sulfide, oxide, nitride, halide, hydride or polymer material classes, including, for example: Thio-LiSICon-based materials (Li2S-P2S5, Li2S-SiS2, Li2S-GeS2), argonite (Li6PS5X (X=Cl, Br or I), Li7PS6, Li7PSe6), garnet (Li7La3Zr2O 12 (LLZO)), perovskite (Li 3x La 2 / 3-3x TiO3 (LLTO)), NaSICon-based materials (Li 1+x Al x Ti 2-x (PO4)3, Li 1.5 Al 0.5 Ge 1.5 (PO4)3), halides (Li2CdCl4), nitrides (Li3N, Li2PN4), hydrides (Li2NH, LiBH4), polymers (PEO-LiTFSI, phosphazene-LiTFSI, PEO-LiFSI). In particular, combinations of the mentioned materials are also possible.

[0018] The electrodes comprise, in particular, a carrier material, such as copper or aluminum foil. The carrier material used is, in particular, copper with a thickness of 3 to 15 μm for the anode and aluminum with a thickness of 3 to 15 μm (micrometers) for the cathode. The carrier material is at least partially covered with active material on at least one of its largest sides, and optionally also on the opposing largest sides. The carrier material is formed as an endless material.

[0019] In step a), the raw material, in particular for the separator material, is provided in the form of a layer. The layer is, in particular, a rectangular parallelepiped-shaped body with a small material thickness, for example, a film-like or planar body, which has two largest side faces of the layer arranged opposite each other and a significantly smaller second side face or edge.

[0020] In step b), the layer is at least partially (or completely) coated with a coating material, in particular a sublimable coating material, to form a coated separator material, where sublimable means that the coating material passes directly from the solid state into the gaseous state after being applied to the separator material.

[0021] It is particularly desirable for this transition to occur under ambient conditions that are not detrimental to other components of the battery cell.

[0022] The coating may be applied by various types of coating techniques, such as spraying, dipping, laminating, and the like.

[0023] In particular, the layer is a planar object, the two largest mutually facing sides of which are completely coated in step b), in particular all sides, i.e. the entire object.

[0024] In particular, the coating is impermeable to at least H2O and / or CO2. Impermeable means that contact between the separator material and said molecules is prevented by the coating or cannot pass through the coating material.

[0025] In particular, the coating material is at least partially composed of camphor (C ), also known as bornan-2-one or 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one. 10 H 16 O) or preferably formed entirely of camphor.

[0026] Camphor sublimes already at room temperature and as a coating is impermeable to at least H2O and / or CO2.

[0027] However, other coating materials with comparable properties may also be used.

[0028] In particular, the coating material is sublimated and at least partially (or completely) removed from the separator material, in particular in a step c) following step b), at a temperature of at most 120°C, preferably at most 100°C, and at a pressure of less than 250 mbar, in particular at a pressure of less than 150 mbar, preferably at a pressure of at most 100 mbar.

[0029] In particular, the coating material is completely removed from the separator material in step c), preferably with the above process parameters.

[0030] In particular, the sublimated coating material is collected after step c) and recycled, in particular the coating material can be reused almost indefinitely, preferably also for the described method.

[0031] In particular, the coated separator material is disposed between at least two electrode materials between steps b) and c). Due to possible sublimation of the coating material, its removal can also be performed after stacking the battery cell components. In this case, the coating material can be drawn out of the stack, for example, along the surfaces of the overlapping components. Contact of the separator material with H2O and / or CO2 is prevented at this point, especially due to contact of the previously coated surfaces with other components of the stack (e.g., electrodes).

[0032] In particular, the electrode materials and the coated separator material arranged to form a stack can be placed in the casing of the battery cell between steps b) and c), and the sublimated coating material can then be removed, in particular through an opening in the casing.

[0033] In particular, the casing is closed after step c).

[0034] The proposed method can, in particular, reduce the cost of manufacturing the battery cell, since a separate inert gas atmosphere is not required, and also improves the storage stability or slows down the degradation of the separator material.

[0035] Furthermore, an all-solid-state battery cell is proposed, which includes at least a battery cell casing, at least two electrodes (anode and cathode) disposed therein, and at least one layer of a separator material produced by the method described above.

[0036] The all-solid-state battery cells are in particular pouch cells (with a deformable battery cell casing made of a pouch film) or prismatic cells (with a shape-invariant battery cell casing). Pouch films are well-known deformable casing members used as battery cell casings for so-called pouch cells. In this case, they are composite materials containing, for example, plastic and aluminum.

[0037] The all-solid-state battery cell is in particular a lithium-ion battery cell or a lithium metal battery cell.

[0038] The all-solid-state battery cell is a power storage device used to store electrical energy in, for example, an automobile. In particular, for example, the automobile has an electric machine (traction drive) that drives the automobile, and in this case, the electric machine can be driven by the electrical energy stored in the all-solid-state battery cell.

[0039] Furthermore, a vehicle is proposed that includes at least a traction drive and a battery that includes at least one of the above-mentioned all-solid-state battery cells, and that is capable of supplying energy to the traction drive via the at least one all-solid-state battery cell.

[0040] In particular, at least one system for processing data is provided, which system is suitably equipped, configured or programmed to perform the method or to control an apparatus that performs the method, or which has means for performing the method.

[0041] These means include, for example, a processor, a memory in which instructions to be executed by the processor are stored, and data lines or transmission devices that allow the transmission of instructions, measurements, data, etc. between the aforementioned elements.

[0042] Furthermore, it is proposed a computer program comprising instructions which, when executed by a computer, cause the computer to carry out the above-mentioned method or the steps of the above-mentioned method.

[0043] Furthermore, a computer readable storage medium is proposed, comprising instructions which, when executed by a computer, cause the computer to perform the above-mentioned method or steps of the above-mentioned method.

[0044] The description of the methods may be transferred to solid-state battery cells, automobiles, systems for data processing, and / or computer-implemented methods (i.e., computer programs and computer-readable storage media), and vice versa.

[0045] The use of the indefinite articles ("ein", "eine", "einer" and "eines"), in particular in the claims and in the descriptions reflecting the claims, does not in itself imply a numeral. Accordingly, correspondingly introduced concepts or components mean that at least one of these concepts or components is present, and in particular that a plurality of these concepts or components may also be present. If a plurality of components ("at least one") may be present, a description of one of these components may, but does not necessarily, apply to all or some of these components as well.

[0046] The invention and the technical environment are explained in more detail below on the basis of the attached drawings. It should be pointed out that the invention is not limited to the described embodiments. Unless otherwise specified, it is also possible to extract parts of the situations illustrated in the drawings and combine them with other components and ideas described in this specification. It should be pointed out that the drawings, and in particular the illustrated scales, are only schematic. [Brief explanation of the drawings]

[0047] [Figure 1] FIG. 1 is a diagram showing the flow of the method. [Figure 2] FIG. 2 is a perspective view showing layers of separator material. [Figure 3] FIG. 2 is a cross-sectional side view showing a stack of electrodes and separator material within a casing of a battery cell. [Figure 4] FIG. 2 is a diagram showing a battery cell.

[0048] The process flow is shown in Figure 1. In step a) 10, the raw material for the separator material 2 is prepared in the form of a layer 3. The layer 3 is a film-like or planar object formed in the shape of a rectangular parallelepiped but with a small material thickness (see Figure 2). In this case, this object has two largest side faces 6 of the layer 3 arranged opposite each other and a significantly smaller other side face or edge.

[0049] Step a1) 13 involves sintering of the layer 3. Step a1) 13 is followed by step b) 11. Within the framework of step b) 11, the complete coating of the layer 3 with the sublimable coating material 4 and the formation of the separator material 2 coated with the coating 5 take place.

[0050] The coated separator material 2 is placed between two electrode materials 7 (anode and cathode) after step b) 11 and before step c) 12. The electrode materials 7 and the coated separator material 2, arranged to form a stack 8, are placed within the casing 9 of the battery cell 1.

[0051] Due to possible sublimation of the coating material 4, removal of the coating material 4 can also be carried out after stacking of the components 4, 7 of the battery cell 1. In this case, the coating material 4 can be drawn out and led out of the stack 8, for example along the surfaces of the overlapping components 4, 7. Contact of the separator material 2 with H2O and / or CO2 is prevented at this point by contact between the surface of the previously coated separator material 2 and other components of the stack 8 (e.g., electrodes 7).

[0052] In step c) 12, which follows step b) 11, the coating material 4 is sublimated at a temperature of up to 120°C and a pressure of less than 250 mbar and completely removed from the separator material 2. The sublimated coating material 4 can be removed through an opening in the casing 9. The casing 9 can be closed after step c) 12, thereby forming a battery cell 1 that is ready for use.

[0053] 2 shows a perspective view of a layer of separator material 2. Layer 3 is a film-like or planar object formed with a rectangular parallelepiped shape but a thin material thickness. In this case, this object has two largest side surfaces 6 of layer 3 arranged opposite each other and a significantly smaller other side surface or edge. At least largest side surface 6 has a coating 5.

[0054] 3 shows a side cross-sectional view of a stack 8 of electrodes (materials 7) and separator material 2 in a casing 9 of a battery cell 1. The coated separator material 2 is placed between two electrode materials 7 (anode and cathode) after step b) 11 and before step c) 12. The electrode materials 7 and the coated separator material 2, arranged to form a stack 8, are placed in the casing 9 of the battery cell 1. In step c) 12, which follows step b) 11, the coating material 4 is sublimated at a temperature of up to 120° C. and a pressure of less than 250 mbar, and completely removed from the separator material 2. The sublimated coating material 4 can be removed through an opening in the casing 9 (see arrow).

[0055] In FIG. 4, a battery cell 1 is shown with a closed casing 9 and a stack 8 arranged therein. [Explanation of symbols]

[0056] 1 battery cell 2 Separator material 3 layers 4. Covering materials 5. Covering 6 Side 7 Electrode material 8 stacks 9 Casing 10. Method step a) 11 Method step b) 12. Method step c) 13 Method step a1)

Claims

1. A method for manufacturing an all-solid-state battery cell (1), the method comprising at least the following steps: a) preparing raw materials for the separator material (2) in the form of a layer (3); b) at least partially coating said layer (3) with a sublimable coating material (4) to form a separator material (2) coated with a coating (5); Including, A method wherein said coating (5) formed in step b) is impermeable to at least H 2 O and CO 2 .

2. 2. The method according to claim 1, wherein the layer (3) is a planar object, the two largest opposite sides (6) of which are completely covered in step b).

3. The method of claim 1, wherein the coating material (4) comprises camphor (C10H16O).

4. 2. The method according to claim 1, wherein in a subsequent step c) the coating material (4) is at least partially removed from the separator material (2) by sublimation at a temperature of up to 120° C. and a pressure of less than 250 mbar.

5. 5. The method of claim 4, wherein in step c) the coating material (4) is completely removed from the layer (3).

6. 6. The method according to claim 4 or 5, wherein after step c) the sublimated coating material (4) is collected and recycled.

7. 6. A method according to claim 4 or 5, wherein the coated separator material (2) is placed between at least two electrode materials (7) between steps b) and c).

8. 8. The method according to claim 7, wherein the electrode material (7) and the coated separator material (2) arranged to form a stack (8) are placed in a casing (9) of the all-solid-state battery cell (1) between steps b) and c).

9. 9. The method according to claim 8, wherein after step c) the casing (9) is closed.

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