DE102017216565A1 - Method for producing an electrical energy storage unit with a solid electrolyte and electrical energy storage unit with a solid electrolyte - Google Patents

Abstract

A method is described for producing an electrical energy storage unit with a solid electrolyte, wherein the electrical energy storage unit comprises a cathode current collector layer, a cathode layer, a separator layer with the solid electrolyte, an anode layer and an anode current discharge layer. In one step, at least a first part of the cathode current collector layer and / or a first part of the cathode layer and / or a first part of the anode layer and / or a first part of the anode current drain layer are oxidized. In a further step, the layers are brought together in such a way that, in the case of an electric circuit closed via the cathode current collector layer and the anode current drain layer, the movement of electrically charged particles through the anode layer, separator layer and cathode layer is possible. Furthermore, an electrical energy storage unit with a solid electrolyte, comprising a Kathodenstromableiterschicht, a cathode layer, a separator layer with the solid electrolyte, an anode layer and a Anodenstromableiterschicht described, wherein a first part of the Kathodenstromableiterschicht and / or a first part of the cathode layer and / or a first part the anode layer and / or a first part of the Anodenstromableiterschicht are oxidized.

Description

The present invention is based on a method for producing an electrical energy storage unit with a solid electrolyte and on a corresponding electrical energy storage unit with a solid electrolyte.

State of the art

Electrical energy can be stored for example by means of batteries. Nowadays, the so-called lithium-ion technology is often used. This has a positive electrode, also referred to as cathode, and a negative electrode, also referred to as anode, on. The cathode and the anode each comprise a current conductor, to which an active material is attached. The active material for the cathode is, for example, a metal oxide. The active material for the anode is, for example, graphite, silicon or lithium. Between cathode and anode while a separator is arranged. This separator prevents a direct short between cathode and anode. The components mentioned are impregnated by a liquid electrolyte, which allows the movement of lithium ions. If the electrolyte is not in liquid but in solid form, it is called a solid electrolyte. In these energy stores, the separator and electrolyte function is taken over by a material component. Although this solid electrolyte could also be placed as a component between the electrodes to prevent a short circuit, but several production reasons speak against it. For reasons of cost and function, the solid electrolyte is as thin as possible and as a rule has layer thicknesses of less than 20 .mu.m, which makes handling in production more difficult. Therefore, the electrolyte is applied to the cathode, for example, in a wet process and can thus be coated or cut at most to the width of the cathode or to the width of the Kathodenableiters. For coating over the substrate width, complicated process steps may be necessary. Therefore, there is an increased short-circuit risk, in particular in the case of multilayer battery cells produced by means of a stacking process, if no corresponding insulating components are provided in the edge region of the electrodes.

The pamphlets WO 2008/011061 A1 and EP 2434 567 A2 describe a method of manufacturing a thin-film lithium battery and a corresponding thin-film lithium battery. In this case, individual layers are coated with an insulating material, for example a polymer.

Disclosure of the invention

Advantages of the invention

Disclosed are a method for producing an electrical energy storage unit with a solid electrolyte and an electrical energy storage unit with solid electrolyte having the characterizing features of the independent claims.

In this case, the electrical energy storage unit with the solid electrolyte comprises a Kathodenstromableiterschicht, a cathode layer, a separator with the solid electrolyte, an anode layer and a Anodenstromableiterschicht, wherein in a first step, at least a first portion of the Kathodenstromableiterschicht and / or a first part of the cathode layer and / or a first Part of the anode layer and / or a first part of the Anodenstromableiterschicht is oxidized. In a further step, the layers are brought together in such a way, preferably by a stacking process and / or a coating process, that the movement of electrically charged particles through the anode layer, separator layer and cathode layer is possible with an electrical circuit closed via the cathode current collector layer and the anode current discharge layer. The sequence of steps, in particular the steps of bringing together, can be chosen arbitrarily. For example, the layers may be brought together as described, with the step of oxidizing the at least one first part thereafter taking place. Likewise, this is possible in reverse order. Furthermore, it is possible that, for example, the cathode layer is already applied to the Kathodenstromableiterschicht and also the anode layer is already applied to the Anodenstromableiterschicht. The bringing together of the layers also includes this embodiment. This ensures in an advantageous manner that points within the electrical energy storage unit, where there is an increased risk of short circuit, are provided by the oxidation with an electrical insulation. This reduces the risk of short circuits and at the same time can be integrated into existing production processes in a relatively simple and cost-effective manner. For example, layers in an electrochemical cell can be stacked regardless of the width of the separator with solid electrolyte. Another advantage is that the oxidation causes no or only a small increase in layer thickness in the existing layers.

Further advantageous embodiments of the present invention are the subject of the dependent claims.

Advantageously, at least a second part of the cathode current drain layer and / or a second part of the anode layer and / or a second part of the anode current drain layer is oxidized within the method, wherein at least the respective first part and the respective second part are disjoint , For example, targeted selective oxidation sites can be generated, whereby the method can be adapted to a variety of cell geometries and cell technologies.

The cathode current drain layer is expediently coated with the cathode layer and / or the anode current drain layer with the anode layer and / or the cathode layer with the separator layer and / or the anode layer with the separator layer, wherein the oxidation of the corresponding first part and / or the corresponding second part before and / or after coating takes place. Thus, it is possible to react flexibly to the requirements of the respective production process and, if appropriate, to provide for division of labor of individual components of the electrical energy storage unit. Furthermore, a simple integration into existing manufacturing processes is possible in an advantageous manner.

The cathode current drain layer and / or the cathode layer and / or the separator layer and / or the anode layer and / or the anode current drain layer are expediently cut, wherein the oxidation of the corresponding first part and / or of the corresponding second part takes place before and / or after the cutting. Thus, it is possible to react flexibly to the requirements of the respective production process and, if appropriate, to provide for division of labor of individual components of the electrical energy storage unit. Furthermore, a simple integration into existing manufacturing process is possible in an advantageous manner.

Expediently, the oxidation comprises application of sulfuric acid and / or oxalic acid and / or chromic acid. Thus, proven oxidation techniques can advantageously be used within the method according to the invention, whereby a high degree of flexibility is achieved within the method. Furthermore, this advantageously achieves a high process reliability.

Conveniently, the oxidizing comprises applying laser light. Thus, even the smallest areas or smallest first and or second parts can be safely and accurately oxidized. Furthermore, the use of health and environmentally hazardous substances is dispensed with, which is advantageous for integration into existing manufacturing processes.

Expediently, the material of the cathode current collector layer comprises aluminum and / or the material of the cathode layer comprises a metal oxide. The respective material is at least partially converted by the oxidation step to alumina. Thus, the oxidation step advantageously produces a very well electrically insulating layer in or on the corresponding first part or the corresponding second part.

Expediently, the oxidized first part of the cathode current drain layer and / or the oxidized first part of the cathode layer and / or the oxidized first part of the anode layer and / or the oxidized first part of the anode current drain layer is largely in area on one or more terminal lugs of the electrical energy storage unit. Thus, it is advantageously ensured that no electrical short circuit can be generated within the electrical energy storage unit by the terminal lugs as components projecting beyond the active materials. This increases the safety of the electrical energy storage unit.

Furthermore, an electrical energy storage unit with a solid electrolyte is described, which comprises a Kathodenstromableiterschicht, a cathode layer, a separator layer with the solid electrolyte, an anode layer and a Anodenstromableiterschicht, wherein a first part of the Kathodenstromableiterschicht and / or a first part of the cathode layer and / or a first part the anode layer and / or a first part of the Anodenstromableiterschicht are oxidized. Thus, the advantages mentioned in the method described above can be realized.

Conveniently, the respective first part is at least partially electrically insulating. Thus, as already mentioned above, the probability of an electrical short circuit within the electrical energy storage unit is reduced. Furthermore, this can be dispensed with additional safety devices that provide security in the event of an electrical short circuit.

Conveniently, the material of the cathode current drain layer comprises aluminum oxide and / or the material of the cathode layer comprises aluminum oxide. Since the corresponding current conductor usually consist of aluminum or aluminum, are thereby advantageously common material combinations covered. Furthermore, the advantages mentioned in the method are realized accordingly.

Expediently, the oxidized first part of the cathode current drainage layer and / or the oxidized first part of the cathode layer and / or the oxidized first part of the anode layer and / or the oxidized first part of the anode current drainage layer projects laterally over at least one, preferably at least two, at least in the region of one or more terminal lugs , in a stacking direction following layers addition. Thus, it is advantageously ensured that even with mechanical stress on the electrical energy storage unit, in particular in bending, an electrical short circuit between the anode and the cathode is prevented. As a result of the projection of the layers following the stacking direction through the oxidized first part, a type of "contact protection" is thus provided which prevents an internal short circuit between the anode and the cathode.

Expediently, the oxidized first part of the cathode current drain layer and / or the oxidized first part of the cathode layer and / or the oxidized first part of the anode layer and / or the oxidized first part of the anode current drain layer are largely in area on one or more terminal lugs of the electrical energy storage unit. Thus, it is advantageously ensured that no electrical short circuit can be generated within the electrical energy storage unit by the terminal lugs as components projecting beyond the active materials. This increases the safety and longevity of the electrical energy storage unit.

list of figures

Advantageous embodiments of the invention are illustrated in the figures and explained in more detail in the following description.

• 1 ein Flussdiagramm des offenbarten Verfahrens gemäß einer ersten Ausführungsform;
• 2 ein Flussdiagramm des offenbarten Verfahrens gemäß einer zweiten Ausführungsform;
• 3 eine schematische Darstellung der offenbarten elektrischen Energiespeichereinheit gemäß einer ersten Ausführungsform;
• 4 eine schematische Querschnittsdarstellung eines in der 3 gezeigten Ausschnitts der offenbarten elektrischen Energiespeichereinheit gemäß der ersten Ausführungsform;
• 5 eine schematische Querschnittsdarstellung des in der 3 gezeigten Ausschnitts gemäß einer zweiten Ausführungsform.

Show it:

• 1 a flowchart of the disclosed method according to a first embodiment;
• 2 a flowchart of the disclosed method according to a second embodiment;
• 3 a schematic representation of the disclosed electrical energy storage unit according to a first embodiment;
• 4 a schematic cross-sectional view of a in the 3 shown section of the disclosed electrical energy storage unit according to the first embodiment;
• 5 a schematic cross-sectional view of the in the 3 shown section according to a second embodiment.

Embodiments of the invention

Identical reference signs denote the same device components or the same method steps in all figures.

1 shows a flowchart of the disclosed manufacturing method of an electric energy storage unit according to a first embodiment. In this case, the electrical energy storage unit has at least one cathode current drainage layer, a cathode layer, a separator layer with a solid electrolyte, an anode layer and an anode current discharge layer. In a first step S11 For example, at least a first portion of the cathode current drain layer, which is often formed of aluminum, is oxidized. In the first part, this converts the aluminum to aluminum oxide, which is a very good insulator and has high dielectric strength. In a second step S12 Subsequently, the layers are brought together such that a functional electrical energy storage unit is formed, that is, in a closed via the Kathodenstromableiterschicht and the Anodenstromableiterschicht electrical circuit, the movement of electrically charged particles through the anode layer, separator and cathode layer is possible. Thus, the electrical energy storage unit can fulfill its function of storage and / or withdrawal of electrical energy. It is possible that, for example, the cathode layer was already applied to the Kathodenstromableiterschicht before the first part of the Kathodenstromableiterschicht is oxidized. This may be due, for example, to production-related reasons, for example due to a lack of inherent stability of the corresponding layers, which make an application to a carrier layer - here, for example, the cathode current drain layer - necessary.

2 shows a flowchart of the disclosed manufacturing method of an electric energy storage unit according to a second embodiment. In a first step S21 In this case, a Kathodenstromableiterschicht is coated with a cathode layer. Typical, but not exclusive, materials for the cathode layer are lithium cobalt oxide, lithium manganese oxide or lithium iron phosphate. Subsequently, in the first step S21 the cathode layer, which is located on the Kathodenstromableiterschicht coated with a Separatorschicht. Typical materials for the separator layer are ceramic electrolytes, polymeric electrolytes or sulfidic glasses. Furthermore, an anode current drain layer is coated with an anode layer. In the case of a lithium metal anode, which may not have a surface-covering arrester layer needed, this coating is eliminated. Typical materials for the anode layer are lithium, silicon, graphite or amorphous carbon. In a second step S22 the layer structure of Kathodenstromableiterschicht, cathode layer and separator layer is cut so that it can be used to produce an electrical energy storage unit in stack construction. Furthermore, in the second step S22 the layer structure of Anodenstromableiterschicht and anode layer cut such that it can be used to produce an electrical energy storage unit in stack construction. Subsequently, in a third step S23 a first part of the Kathodenstromableiterschicht, for example, a laterally protruding terminal lug, oxidized. In a fourth step S24 a second part of the cathode current collector layer is oxidized, the first part and the second part being completely different. Subsequently, in a fifth step S25 the layers, that is, the layer structure of Kathodenstromableiterschicht, cathode layer and separator layer and the layer structure of Anodenstromableiterschicht and anode layer brought together such that a functional electric energy storage unit is formed, which can store and / or withdraw electrical energy, or that in a cathode overflow and Anodenstromableiterschicht Closed electric circuit, the movement of electrically charged particles by anode layer, separator and cathode layer is possible.

3 shows a schematic representation of the disclosed electrical energy storage unit 300 according to a first embodiment in a plan view.

Here is a Kathodenstromableiterschicht 301 pictured, on the underside of a in 3 invisible cathode layer is applied. A part of the cathode current drainage layer forms a so-called terminal lug 303 , Furthermore, a separator layer 305 and for clarity, an anode layer 307 shown, wherein the anode layer 307 actually flush with the separator layer 305 concludes and was drawn here only for clarity. Furthermore, a part of a Anodenstromableiterschicht is shown, which is a connecting lug 302 forms and in a lithium metal anode is not always necessary. Furthermore, a section I registered, which in a cross-sectional view in the 4 is explained in more detail.

4 shows a schematic cross-sectional view of the in the 3 shown detail I the disclosed electrical energy storage unit 300 according to the first embodiment. The cross section takes place along the in 3 shown line A - A , The layer structure is described starting from the uppermost layer in the direction of a stacking direction V. The uppermost layer is from the Kathodenstromableiterschicht 301 formed, wherein a part of the Kathodenstromableiterschicht 301 the connection flag 303 forms. A section 408 the Kathodenstromableiterschicht 301 is oxidized and is thus electrically insulating against its environment. To the cathode current collector layer 301 borders a cathode layer 403 , To the cathode layer 403 adjoins a separator layer 305 which comprises a solid electrolyte. To the separator layer 305 borders an anode layer 307 , which in turn to a Anodenstromableiterschicht 411 borders. To the anode current arrester layer 411 borders another anode layer 410 , To the anode layer 410 adjoins another separator layer 406 , to which in turn another cathode layer 404 borders. To the other cathode layer 404 adjoins another Kathodenstromableiterschicht 402 , wherein a part of the further Kathodenstromableiterschicht 402 the further connection flag 412 forms. The further cathode current collector layer 402 has another section 409 on, which is oxidized and thus electrically insulating against its environment. As the drawing can be seen, is due to the oxidized sections 408 . 409 the risk of a short circuit between the anode layers 307 . 410 or the Anodenstromableiterschicht 411 and the cathode layers 403 . 404 or the Kathodenstromableiterschichten 301 . 402 considerably reduced.

5 shows a schematic cross-sectional view of the in the 3 shown detail I according to a second embodiment along in 3 shown line A - A , There is the essential difference to the in 4 described structure in that the oxidized sections 508 . 509 do not start flush with the layer below or above, but slightly outwards on the connection lugs 303 . 412 are discontinued. This can turn out to be advantageous in the production process or be easier to implement.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2008/011061 A1 [0003]
• EP 2434567 A2 [0003]

Claims (13)

Method for producing an electrical energy storage unit (300) with a solid electrolyte, wherein the electrical energy storage unit (300) comprises a cathode current collector layer (301, 402), a cathode layer (403, 404), a separator layer (305, 406) with the solid electrolyte, an anode layer ( 307, 410) and an anode current drain layer (411), comprising the steps of: a) oxidizing at least a first part (408, 409, 508, 509) of the cathode current drain layer (301, 402) and / or a first part of the cathode layer (403, 404) and / or a first part of the anode layer (307, 410) and or a first part of the anode current drain layer (411); b) contacting the layers in such a way that, in the case of a electrical circuit closed via cathode current drain layer (301, 402) and anode current drain layer (411), electrically charged particles are formed by anode layer (307, 410), separator layer (305, 406) and cathode layer (403, 404) move. Method according to Claim 1 , further comprising: c) oxidizing at least a second part (408, 409, 508, 509) of the cathode current collector layer (301, 402) and / or a second part of the cathode layer (403, 404) and / or a second part of the anode layer (307 , 410) and / or a second portion of the anode current drain layer (411), wherein at least the respective first portion (408, 409, 508, 509) and the respective second portion (408, 409, 508, 509) are disjoint. Method according to one of the preceding claims, further comprising: d) coating the cathode current collector layer (301, 402) with the cathode layer (403, 404) and / or the anode current discharge layer (411) with the anode layer (307, 410) and / or the cathode layer (403, 404) with the separator layer (305, 406) and / or the anode layer (307, 410) with the separator layer (305, 406), wherein the oxidation takes place in step a) before and / or after the coating in step d). Method according to one of the preceding claims, further comprising: e) cutting the cathode current collector layer (301, 402) and / or the cathode layer (403, 404) and / or the separator layer (305, 406) and / or the anode layer (307, 410) and / or the anode current discharge layer (411) the oxidation takes place in step a) before and / or after the cutting in step e). A method according to any one of the preceding claims, wherein the oxidizing comprises applying sulfuric acid and / or oxalic acid and / or chromic acid. A method according to any one of the preceding claims, wherein the oxidizing comprises applying laser light. The method of claim 1, wherein the material of the cathode current collector layer comprises aluminum and / or the material of the cathode layer comprises a metal oxide and wherein the respective material is at least partially converted to aluminum oxide by the oxidation. Method according to one of the preceding claims, wherein the oxidized first part (408, 409, 508, 509) of the Kathodenstromableiterschicht (301, 402) and / or the oxidized first part of the cathode layer (403, 404) and / or the oxidized first part the anode layer (307, 410) and / or the oxidized first part of the Anodenstromableiterschicht (411) in terms of area for the most part on one or more terminal lugs (302, 303, 412) of the electrical energy storage unit (300). An electrical energy storage unit (300) comprising a solid state electrolyte comprising a cathode current drain layer (301, 402), a cathode layer (403, 403), a separator layer (305, 406) with the solid electrolyte, an anode layer (307, 410) and an anode current drain layer (411) , characterized in that a first part (408, 409, 508, 509) of the cathode current drain layer (301, 402) and / or a first part (408, 409, 508, 509) of the cathode layer (403, 404) and / or a first portion of the anode layer (307, 410) and / or a first portion of the anode current drain layer (411) are oxidized. Electric energy storage unit (300) according to Claim 9 , wherein the respective first part (408, 409, 508, 509) is at least partially electrically insulating. Electric energy storage unit according to Claim 9 or 10 wherein the material of the cathode current collector layer (301, 402) comprises aluminum oxide and / or the material of the cathode layer (403, 404) comprises aluminum oxide. Electric energy storage unit (300) according to one of Claims 9 to 11 wherein the oxidized first part (408, 409, 508, 509) of the cathode current collector layer (301, 402) and / or the oxidized first part of the cathode layer (403, 404) and / or the oxidized first part of the anode layer (307, 410) and / or the oxidized first part of the anode current discharge layer (411) at least in the region of one or more terminal lugs (302, 303, 412) extends laterally beyond at least one subsequent layer in a stacking direction. Electric energy storage unit (300) according to one of Claims 9 to 12 wherein the oxidized first part (408, 409, 508, 509) of the cathode current collector layer (301, 402) and / or the oxidized first part of the cathode layer (403, 404) and / or the oxidized first part of the anode layer (307, 410 ) and / or the oxidized first part of the Anodenstromableiterschicht (411) in terms of area for the most part on one or more terminal lugs (302, 303, 412) of the electrical energy storage unit (300).

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