ENERGY STORAGE CELL

Abstract

This relates to an energy storage cell comprising: (i) a glass fiber fabric with a first side and a second side opposite it; (ii) wherein the first side is coated with a first metal layer made of a first metal, in particular copper, and the second side is coated with a second metal layer made of a second metal, in particular aluminum; (iii) wherein the first metal layer is coated with a first active material layer made of a first active material, and the second metal layer is coated with a second active material layer made of a second active material, wherein the first active material and the second active material are each suitable for attracting ions, in particular lithium ions, respectively.to outsource; (iv) wherein the fiberglass fabric is suitable for conducting ions, in particular lithium ions, using an electrolyte, thereby enabling the exchange of ions between the first active material layer and the second active material layer.

Description

[0001] The present invention relates to an energy storage cell, a battery module, a motor vehicle and a method for producing an energy storage cell.

[0002] In the field of energy storage cells, especially battery cells, especially lithium-ion battery cells, cylindrical and prismatic hardcase and pouch-shaped battery cells are known. Battery cells for storing electrical energy play a central role in the field of electromobility, both in vehicles with purely electric drives and in vehicles with hybrid drives. For example, a battery module for a 12V starter battery can have four battery cells, whereas a high-voltage storage device can have several battery modules. Cylindrical lithium-ion battery cells can have an electrode winding in which the electrodes, including the separator, are spirally wound around a winding core in the sequence separator-anode-separator-cathode. The electrodes, in particular composite electrodes, can comprise a mixture of active material, binder, and conductive additives.This mixture can be applied as a thin layer on both sides of a current collector.

[0003] In the assembled state, a battery cell may have a loosely wound or stacked electrode-separator assembly. This loose arrangement can cause the electrodes to shift relative to each other during manufacturing (winding / stacking process) and / or during operation within the battery cell, resulting in misalignment and potentially rendering the battery cell unreliable. For example, this shift during operation can trigger an internal electrical short circuit.

[0004] It is also known to laminate electrode-separator assemblies using a hot-pressing process and form them into a stack. The effect of temperature and pressure on the separator during lamination can change its pore structure, which can also cause the separator to shrink. Furthermore, such a process requires an adhesion promoter applied between interfaces, which requires a volume that reduces the energy density of the battery cell. Furthermore, such a process increases production costs.

[0005] It is therefore an object of the present invention to provide an energy storage cell which is improved with regard to the above-mentioned problems.

[0006] This object is achieved according to the teaching of the independent claims. Various embodiments and further developments of the invention are the subject of the dependent claims.

[0007] A first aspect of the solution relates to an energy storage cell, comprising: (i) a glass fiber fabric having a first side and a second side opposite thereto; (ii) wherein the first side is coated with a first metal layer made of a first metal, in particular copper, and the second side is coated with a second metal layer made of a second metal, in particular aluminum; (iii) wherein the first metal layer is coated with a first active material layer made of a first active material, and the second metal layer is coated with a second active material layer made of a second active material, wherein the first active material and the second active material are each suitable for introducing or removing ions, in particular lithium ions.(iv) wherein the glass fiber fabric, in particular having porous structures, is suitable for conducting ions, in particular lithium ions, using an electrolyte, whereby the ions can be exchanged between the first active material layer and the second active material layer.

[0008] The terms "comprises," "includes," "includes," "has," "has," "with," or any other variation thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a method or apparatus that includes or has a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or that are inherent in such a method or apparatus.

[0009] Furthermore, unless explicitly stated otherwise, "or" refers to an inclusive "or" rather than an exclusive "or." For example, a condition A or B is satisfied by one of the following conditions: A is true (or present) and B is false (or absent), A is false (or absent) and B is true (or present), and both A and B are true (or present).

[0010] The terms "a" or "an" as used herein are defined as "one or more." The terms "another" and "another," and any other variations thereof, are defined as "at least one other."

[0011] The term “plurality” as used here shall mean “two or more”.

[0012] The term “configured” or “set up” to fulfil a specific function (and respective variations thereof) as used here is to be understood to mean that the corresponding device is already in a design or setting in which it can carry out the function or is at least adjustable - i.e. configurable - so that it can carry out the function after being set accordingly. The configuration can be carried out, for example, by appropriately setting parameters of a process sequence or of switches or the like for activating or deactivating functionalities or settings. In particular, the device can have a plurality of predetermined configurations or operating modes, so that the configuration can be carried out by selecting one of these configurations or operating modes.

[0013] The term "active material" as used here refers in particular to a material that can be electrochemically active and that is configured for coating electrodes for electrode windings for battery cells, and into which ions, in particular lithium ions, can be incorporated. The active material for the cathode can in particular comprise lithium nickel manganese cobalt oxide (NMC), lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium nickel cobalt aluminum oxide (NCA), lithium nickel manganese oxide (LMR), lithium manganese oxide spinel (LMO), lithium iron phosphate (LFP), lithium manganese iron phosphate (LMFP), lithium nickel manganese oxide spinel (LNMO), a combination of the aforementioned materials, or another material. Lithium nickel manganese cobalt oxide (NMC) can be present in various stoichiometries, in particular as NMC111, NC532, NMC6222 or NMC811.

[0014] The active material for the anode can be graphite (natural graphite, synthetic graphite), hard carbon, soft carbon, silicon (Si), nano-silicon, silicon oxide (SiOx), silicon carbide (SiC), silicon-carbon composites, lithium titanate (LTO, Li4Ti5O 12) , metallic lithium (Li) and combinations thereof or another material.

[0015] The term "binder" as used here refers in particular to a binding agent (also referred to as an electrode binder) that can be applied to a current collector with an active material and conductive additives. The binding agent is in particular selected from the group consisting of polyethylene oxide (PEO), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), cellulose, acrylates (e.g., polymethyl methacrylate), polyvinylpyrrolidone (PVP), styrene-butadiene rubber (SBR), polyisobutene (PIB), and mixtures thereof.

[0016] The term “separator” or “separator layer” as used here refers in particular to an electrically insulating device which separates and spaces an anode from a cathode. The separator or separator layer can also at least partially accommodate an electrolyte, wherein the electrolyte preferably contains lithium ions. The electrolyte can also be electrochemically bonded to adjacent layers of an electrode stack or electrode coil. A separator is preferably thin-walled, particularly preferably as a microporous film or a fabric, particularly a glass fiber fabric. The separator layer or separator is preferably wetted with an additive which also increases the mobility of the separator layer or separator. Wetting is particularly preferably carried out with an ionic additive. The separator layer or separator layer preferably extendsThe separator extends at least partially beyond a boundary edge of at least one electrode. Particularly preferably, the separator layer or separator extends beyond all boundary edges of adjacent electrodes. The separator can also comprise a solid, inorganic lithium-ion conductor.

[0017] The term “electrolyte” as used here refers to a liquid, gel-like, or solid material through which ions can be conducted, thereby enabling current to be transported between the electrodes of a battery, in particular between a cathode and an anode. In contrast to electronic conductivity (through electrons) in the electrode materials, the electrolyte must be ionically conductive, i.e. it must conduct electrical current by transporting charged atoms or molecules (ions). In particular, the electrolyte has a high electrical resistance. The electrolyte is advantageously chemically stable over a wide temperature window and electrochemically stable against decomposition over the largest possible voltage window. Ideally, it is non-toxic and non-flammable and has at least a high flash point and low heat of combustion.Liquid systems may be preferred over polymer, gel and solid electrolytes due to better conductivity.

[0018] The term "current conductor" as used here refers to an element made of an electrically conductive material. It serves to conduct current or electrons between two geometrically separated points and can simultaneously serve as a mechanical support, for example, for coatings applied to it.

[0019] The term "glass fiber fabric" as used here refers specifically to fiber-based fabrics. The glass fiber fabric can, in particular, be designed as a randomly laid fiber fabric and have porous structures.

[0020] The energy storage cell according to the first aspect makes it possible to ensure that the first metal layer and the second metal layer are each integrally connected to the glass fiber fabric. During operation of the energy storage cell, the first metal layer, in particular, can have a different electrical polarity than the second metal layer, and an electrical voltage of the energy storage cell can be tapped at the first metal layer and the second metal layer. Furthermore, the first active material layer and the second active material layer are each integrally connected to the respective first metal layer or the second metal layer. This achieves a firm connection between the aforementioned components or layers, which also results in a defined positioning of the individual components or layers relative to one another.This can largely prevent, or at least reduce, any displacement of the bonded layers. Furthermore, experimental studies have shown that metallization of the surfaces of the glass fiber fabric, i.e., the first and second sides, is sufficient to ensure collector function with respect to current-carrying capacity.

[0021] Preferred embodiments of the energy storage cell are described below, which can be combined with each other as well as with the other aspects described, unless this is expressly excluded or is technically impossible.

[0022] In some embodiments, a surface of a glass fiber, in particular surfaces of all glass fibers, of the first side or the second side of the glass fiber fabric has a region coated with the first metal layer or the second metal layer and an uncoated region, wherein the uncoated region is oriented towards an inner region of the glass fiber fabric. Such a metal layer can be applied to a glass fiber fabric finished, in particular according to the prior art, with comparatively little effort, since the first side and the second side are directly accessible before coating with the first active material and / or the second active material and can therefore be coated in particular by a deposition process. An inner region is understood to be a region which is within the glass fiber fabric, i.e. not on a surface orone side of the glass fiber fabric and therefore cannot be coated directly and therefore remains uncoated in the coating described.

[0023] In some embodiments, a surface of a glass fiber, in particular surfaces of all glass fibers, of the first side or the second side of the glass fiber fabric is substantially completely coated with the first metal or the second metal. Electrical contact can be improved by a complete coating. Since this coating of the glass fiber preferably takes place before the glass fiber is woven into the glass fiber fabric, since otherwise the coating would be complex due to the inaccessible areas, contamination of the glass fiber fabric or the energy storage cell with metal particles during coating can be reduced. A substantially complete coating is understood to mean a coating in which at least 90% of the surface of the glass fiber is coated.

[0024] In some embodiments, the first metal, which is particularly designed as an anode current collector, comprises copper or nickel, and / or the second metal, which is particularly designed as a cathode current collector, comprises aluminum. Copper, nickel, and aluminum each exhibit good electrical conductivity and are therefore preferred materials for the first metal layer and the second metal layer.

[0025] A second aspect of the solution relates to a battery module having a plurality of energy storage cells according to the first aspect.

[0026] In some embodiments, the majority of energy storage cells are arranged side by side, such that adjacent energy storage cells are mechanically connected to one another by coatings of the same active material. This reduces the risk of an electrical short circuit in the event of a relative displacement of the energy storage cells, since metal layers made of the same material, such as the first metal or the second metal, are arranged opposite one another in adjacent battery cells.

[0027] A third aspect of the solution relates to a motor vehicle with an electric drive or a hybrid drive and a battery module according to the second aspect.

[0028] A fourth aspect of the solution relates to a method, in particular a computer-implemented method, for producing an energy storage cell, comprising the following steps: (i) providing a glass fiber fabric having a first side and a second side opposite thereto; (ii) coating the first side with a first metal to form a first metal layer; (iii) coating the second side with a second metal to form a second metal layer; (iv) coating the first metal layer with a first active material; (v) coating the second metal layer with a second active material; wherein the first active material and the second active material are each suitable for introducing or removing ions, in particular lithium ions.(vi) wherein the glass fiber fabric, in particular having porous structures, is suitable for conducting ions, in particular lithium ions, using an electrolyte, whereby the ions can be exchanged between the first active material layer and the second active material layer.

[0029] The second aspect makes it possible to manufacture the energy storage cell in an integrated process. In contrast to known methods in which electrodes made of different metals are coated separately, and a separator is subsequently arranged between the electrodes, according to the second aspect, the first metal layer and the second metal layer are applied directly to the separator. This simplifies production.

[0030] Preferred embodiments of the method are described below, which can be combined with each other as well as with the other aspects described, unless this is expressly excluded or is technically impossible.

[0031] In some embodiments, coating the first side with the first metal and coating the second side with the second metal occur substantially simultaneously. This eliminates a work step or a separate coating step, and coating the first side and the second side can be performed more effectively.

[0032] In some embodiments, the coating with the first active material and the coating with the second active material occur substantially simultaneously. This eliminates a work step or a separate coating step, and coating of the first metal layer and the second metal layer can be performed more effectively.

[0033] Essentially simultaneous coating is understood to mean coating that occurs essentially at the same time. Essentially simultaneous coating occurs when at least one section or region of the battery cell is coated simultaneously on both sides described.

[0034] In some embodiments, the coating of the first side with the first metal and / or the coating of the second side with the second metal is carried out by substantially completely coating a surface of a glass fiber of the glass fiber fabric before it is woven into the glass fiber fabric, and subsequently weaving it into the glass fiber fabric on the corresponding first side or second side. This can reduce contamination of the glass fiber fabric or the energy storage cell with metal particles, since the metal coating is applied outside the glass fiber fabric. Furthermore, substantially completely coating the surface of the glass fiber can enable improved electrical contact with this coating, and charge carriers can be absorbed more effectively.

[0035] The features and advantages explained with regard to the first aspect of the solution also apply accordingly to the other aspects described.

[0036] Further advantages, features and possible applications emerge from the following description of preferred embodiments in conjunction with the figures.

[0037] This shows Fig. 1 schematically shows a battery cell according to an embodiment; Fig. 2 schematically shows a battery cell stack according to an embodiment; Fig. 3 schematically shows a flow chart illustrating a preferred embodiment of a method; Fig. 4 schematically shows a wet coating according to an embodiment; and Fig. 5 schematically shows a dry coating according to an embodiment.

[0038] Throughout the figures, the same reference numerals are used for the same or corresponding elements.

[0039] In Fig. 1 schematically shows a battery cell 100 according to an embodiment.

[0040] The battery cell 100 has a glass fiber fabric 110 made of a plurality of glass fibers 120. The glass fiber fabric 110 is designed as a mechanically flexible sheet-like structure. The glass fiber fabric 110 is electrically insulating but permeable to ions or ion-conducting, in particular permeable to lithium ions. In this respect, the glass fiber fabric 110 acts as a separator in the battery cell 100. The glass fiber fabric 110 is coated with a metal on opposite sides. The glass fiber fabric 110 has a copper layer 130 on a first side, which forms an anode in the battery cell 100. On a second side opposite the first side, the glass fiber fabric 110 has an aluminum layer 140, which forms a cathode in the battery cell 100. A first active material layer 150 made of a first active material, in particular graphite, is arranged on the copper layer 130.A second active material layer made of a second active material, in particular NMC, is arranged on the aluminum layer 140.

[0041] The first active material and the second active material are each suitable for intercalating or deintercalating ions, in particular lithium ions, so that ions can be exchanged through the glass fiber fabric 110 between the first active material layer 150 and the second active material layer 160 during operation of the battery cell 100.

[0042] In the present embodiment, the glass fibers 120, which are coated with aluminum or copper, are each coated over their entire surface. This can be achieved by coating these glass fibers 120 separately before being woven into the glass fiber fabric 110. By completely coating the glass fibers 120 arranged on one side of the glass fiber fabric 110, a larger metallic contact area can be achieved.

[0043] It is also conceivable for glass fibers 120 of an already finished glass fiber fabric 110 to be coated with aluminum or copper, in particular by a deposition process. In this case, the copper layer 130 and the aluminum layer 140 are each formed only on one area of ​​a surface of a glass fiber 120, and another area of ​​the surfaces of the affected glass fibers 120, which is arranged within the glass fiber fabric 110, is uncoated.

[0044] In Fig. 2 schematically shows a battery cell stack 200 according to one embodiment.

[0045] The battery cell stack 200 comprises four battery cells 100 arranged one above the other in the y-direction of the illustrated coordinate system. Likewise, the battery cell stack 200 may comprise fewer or more than four battery cells 100.

[0046] In this case, adjacent battery cells 100 of the battery cell stack 200 are mechanically connected to one another by coatings of the same active material 150 or 160. For example, the lowest or first battery cell 100 in the drawing plane and with respect to the y-axis is mechanically connected to the next, i.e., second, battery cell 100 arranged above it by their respective first active material layers 150. This means that the first active material layer 150 of the lowest battery cell 100 is mechanically connected to the first active material layer 150 of the battery cell 100 arranged above it. This is made possible by the fact that the lowest battery cell is rotated by 180° with respect to the y-direction relative to the battery cell 100 located above it.

[0047] The copper layers 130 of the battery cells 100 are each connected to a first electrical line 210. The aluminum layers 130 of the battery cells 100 are each connected to a second electrical line 220. This allows a total voltage of the battery cells 100 connected in parallel, which is indicated by the double arrow and the symbol for voltage "U" in Fig. 2 is shown.

[0048] This arrangement also offers the advantage that the risk of an electrical short circuit is reduced when the battery cells 100 or the respective layers of a battery cell 100 are displaced relative to one another during operation. This results from the fact that metal layers made of the same material of adjacent battery cells 100 are arranged opposite one another. With respect to the bottommost battery cell 100 in the present exemplary embodiment and the battery cell 100 arranged above it, their copper layers 130 are arranged opposite one another, with their respective first active material layers 150 being arranged adjacent to one another in between.

[0049] The battery cell stack 200 can be installed in a housing (not shown here). The dimensions of the housing relative to the battery cell stack 200 can be selected such that, during a first cycling of the battery cell stack 200, the volume of the battery cell stack 200 expands, thereby compressing the battery cell stack 200 in the housing. This can further prevent displacement of the battery cells 100 or their layers relative to one another.

[0050] In Fig. 3 schematically shows a flow chart 300 for illustrating a preferred embodiment of a method for producing a battery cell 100, comprising the following steps: In a first step S310 of the method, a glass fiber fabric 110 is provided having a first side and a second side opposite thereto.

[0051] In a further step S320 of the method, the first side is coated with copper to form a copper layer 130 and the second side is coated with aluminum to form an aluminum layer 140. The coating with the copper layer 130 and the aluminum layer 140 takes place essentially simultaneously.

[0052] During operation of the battery cell 100, the copper layer 130 has a different electrical polarity than the aluminum layer 140, and an electrical voltage of the battery cell 100 can be tapped at the copper layer 130 and the aluminum layer 140.

[0053] In a further step S330 of the method, the copper layer 130 is coated with a first active material, in particular graphite, and the aluminum layer 140 is coated with a second active material, in particular lithium nickel manganese cobalt oxide (NMC). The coating with the first active material and the second active material 140 takes place essentially simultaneously.

[0054] The first active material and the second active material are each suitable for storing or removing ions, in particular lithium ions.

[0055] The glass fiber fabric 110 is suitable for conducting the lithium ions, whereby the lithium ions can be exchanged between the first active material layer 150 and the second active material layer 160.

[0056] In Fig. 4 schematically shows a wet coating process according to one embodiment. This process shows a section of a battery cell 100 being coated in the y-direction. One region of the glass fiber fabric 100 is already coated with a copper layer 130 or aluminum layer 140, as well as a first active material layer 150 or a second active material layer 160. Another region of the glass fiber fabric 100, however, is coated with a copper layer 130 or aluminum layer 140, but not yet with a first active material layer 150 or a second active material layer 160. The coating of the first active material layer 150 or the second active material layer 160 is carried out by what is known as wet coating using the schematically illustrated nozzles 400, which coat the aluminum- or copper-coated glass fiber fabric 110 with the respective active material from two sides in the x-direction, essentially simultaneously.

[0057] In Fig.5 schematically shows a dry coating according to one embodiment. This shows a section of a battery cell 100 which is being coated in the y-direction. One area of ​​the glass fiber fabric 100 is already coated with a copper layer 130 or aluminum layer 140, as well as a first active material layer 150 or a second active material layer 160. Another area of ​​the glass fiber fabric 100, however, is coated with a copper layer 130 or aluminum layer 140, but not yet with a first active material layer 150 or a second active material layer 160. The coating of the first active material layer 150 or the second active material layer 160 is carried out by what is known as dry coating using the schematically illustrated lamination device 500, which laminates the battery cell 100 coated with aluminum or copper in the x-direction from two sides.Copper-coated glass fiber fabric 110 is coated with the respective active material essentially simultaneously. Lamination by the lamination device is carried out at a predetermined temperature and a predetermined pressure.

[0058] While at least one exemplary embodiment has been described above, it should be appreciated that a wide variety of variations exist. It should also be understood that the described exemplary embodiments are merely non-limiting examples and are not intended to limit the scope, applicability, or configuration of the devices and methods described herein. Rather, the foregoing description will provide one skilled in the art with guidance for implementing at least one exemplary embodiment, it being understood that various changes in the operation and arrangement of the elements described in an exemplary embodiment may be made without departing from the subject matter as defined in the appended claims, as well as their legal equivalents. LIST OF REFERENCE SYMBOLS 100 battery cells 110 glass fiber fabric 120 fiber optics 130 copper layer 140 aluminum layer 150 First active material layer 160 Second active material layer 200 battery cell stacks 210 First electrical line 220 Second electrical line 300 Flowchart to illustrate a process S310 Provide glass fiber fabric S320 Coating with aluminum or copper S330 Coating with a first active material layer or a second active material layer 400 nozzle 500 lamination facility

Claims

[1] Energy storage cell (100), comprising: A glass fiber fabric (110) having a first side and an opposite second side; wherein the first side is coated with a first metal layer (130) made of a first metal, and the second side is coated with a second metal layer (140) made of a second metal; wherein the first metal layer (130) is coated with a first active material layer (150) made of a first active material, and the second metal layer is coated with a second active material layer (160) made of a second active material, wherein the first active material and the second active material are each suitable for intercalating or releasing ions; wherein the glass fiber fabric (110) is capable of conducting ions using an electrolyte, whereby the ions can be exchanged between the first active material layer (150) and the second active material layer (160). [2] Energy storage cell according to claim 1, wherein a surface of a glass fiber (120) of the first side or the second side of the glass fiber fabric (110) has a region coated with the first metal layer (130) or the second metal layer (140) and an uncoated region, the uncoated region being aligned towards an inner region of the glass fiber fabric (110). [3] The energy storage cell of claim 1, wherein a surface of a glass fiber (120) of the first side or the second side of the glass fiber fabric (110) is substantially completely coated with the first metal or the second metal. [4] Energy storage cell according to claim 1, wherein the first metal comprises copper or nickel, and / or the second metal comprises aluminum. [5] Battery module (200) with a plurality of energy storage cells (100) according to one of the preceding claims. [6] Battery module (200) according to claim 5, wherein the plurality of energy storage cells (100) are arranged next to one another in such a way that adjacent energy storage cells (100) are mechanically connected to one another by coatings of the same active material. [7] Motor vehicle with an electric drive or a hybrid drive and a battery module according to claim 5 or 6. [8] Method for producing an energy storage cell (100), comprising the following steps: Providing a glass fiber fabric (110) having a first side and an opposite second side; coating the first side with a first metal to form a first metal layer (130); coating the second side with a second metal to form a second metal layer (140); Coating the first metal layer (130) with a first active material; Coating the second metal layer (140) with a second active material; wherein the first active material and the second active material are each suitable for intercalating or releasing ions; wherein the glass fiber fabric (110) is capable of conducting ions using an electrolyte, whereby the ions can be exchanged between the first active material layer (150) and the second active material layer (160). [9] The method of claim 8, wherein coating the first side with the first metal and coating the second side with the second metal occur substantially simultaneously. [10] The method according to claim 8 or 9, wherein the coating with the first active material and the coating with the second active material occur substantially simultaneously. [11] Method according to one of claims 8 to 10, wherein the coating of the first side with the first metal and / or the coating of the second side with the second metal is carried out in that a surface of a glass fiber (120) of the glass fiber fabric (110) is substantially completely coated before it is woven into the glass fiber fabric (110), and is subsequently woven onto the corresponding first side or second side with the glass fiber fabric (110).

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