Bipolar rechargeable battery, method for producing a rechargeable battery, and motor vehicle comprising a rechargeable battery

Abstract

The invention relates to a bipolar rechargeable battery for storing electrical energy, wherein a plurality of electrical cells are arranged in multiple layers one above the other. Each cell has an anode and a cathode, each of which is applied to a carrier layer, wherein a carrier layer is arranged between each pair of adjacent cells, on which carrier layer the anode of the one of the two adjacent cells and the cathode of the other of the two adjacent cells are applied. The anode and the cathode are electrically connected to one another by the carrier layer. The carrier layer is made of electrically conductive plastic. The carrier layer comprises a metallic structure which extends in a planar manner parallel to the carrier layer.

Description

[0001] M149PC2403

[0002] - 1 -

[0003] Bipolar accumulator, method for manufacturing an accumulator and motor vehicle with an accumulator

[0004] Description

[0005] The invention relates to a bipolar accumulator according to the preamble of claim 1, as well as a method for manufacturing such a bipolar accumulator and a motor vehicle with such an accumulator or an accumulator manufactured according to such a method.

[0006] Bipolar batteries are fundamentally known. They are batteries that are based on the principle of a voltaic pile.

[0007] Bipolar batteries of this type contain multiple electrical cells arranged in layers. Each cell has an anode and a cathode, each mounted on a carrier layer. The distinguishing feature of a bipolar battery is that an electrically conductive carrier layer is positioned between each pair of adjacent cells. On this carrier layer, the anode of one of the two adjacent cells and the cathode of the other are located. The two adjacent cells are electrically connected to each other via this carrier layer. In simpler terms, a bipolar battery combines multiple batteries connected in series.

[0008] Furthermore, accumulators of the type in question contain an electrolyte. The electrolyte enables the transport of ions between the anode and cathode. Accordingly, the electrolyte is located between the anode and cathode. The electrolyte can be in the form of a liquid, a solid, and / or a gel. As a rule, the electrolytes of individual cells must be kept separate from one another. This applies particularly to liquid electrolytes. M149PC2403

[0009] - 2 -

[0010] Such bipolar batteries inherently possess high potential. In principle, a single compact bipolar battery can replace an array of multiple conventional batteries connected in series. This would result in weight and cost savings.

[0011] Nevertheless, bipolar batteries have not become established in technology. This is due, for example, to the fact that many battery types, such as lithium-ion batteries, cannot be easily implemented as bipolar batteries. However, lithium-ion batteries are currently the battery type of choice in the vast majority of applications due to their excellent properties. It would therefore be desirable to create a battery that makes the advantages of a bipolar battery available for such battery types, especially lithium-ion batteries.

[0012] In practice, however, this presents a number of problems. For example, conventional batteries use metal layers as substrates for the electrodes. Their primary function is to conduct current to the electrode during charging and / or discharging. This is achieved primarily due to the excellent conductivity of the metal substrates. They offer relatively little resistance to the current when it flows in a direction parallel to the main orientation of the substrate (and thus also the electrode layer), even if the cross-section of the substrate is comparatively small in such a current flow direction. In other words, the metallic substrates can thus ensure a good "surface distribution" of the current to and from the respective electrode.

[0013] However, bipolar batteries present the problem that the substrate layer must be suitable for both the anode and the cathode. For example, conventional lithium-ion batteries typically use aluminum foil for the cathode and copper foil for the anode.

[0014] - 3 -det. However, it has been shown that aluminum foils are unsuitable as a substrate for the anode, while copper foils are unsuitable as a substrate for the cathode. This unsuitability results from the fact that the metallic foils must not participate in the reactions within the cells. Aluminum foils, however, form an alloy with lithium even at room temperature when used as the anode material. Copper foils, on the other hand, are oxidized when used as a substrate for the cathode due to their positive electrical potential (an aluminum foil, when used as a substrate for the cathode, is protected from further corrosion by a stable oxide layer – a so-called passivation layer).Therefore, the search for a suitable substrate layer presents a crucial problem when it comes to developing bipolar lithium-ion batteries that meet today's battery requirements, especially regarding their durability.

[0015] Another problem in the production of bipolar batteries is the differing requirements for coating the cathode and anode sides. The anode layer, as well as the cathode layer and its precursors – usually doughy or pasty masses – exhibit different properties, making a substrate layer containing both layers difficult to handle from a process engineering perspective.

[0016] It has been demonstrated in the past that electrically conductive plastics can be used to produce carrier layers that are suitable, in terms of their mechanical and especially chemical properties, for use as a carrier layer in bipolar batteries. It has been shown that the conductivity of such carrier layers made of conductive plastics is quite sufficient to ensure adequate conductivity of the carrier layer in a bipolar battery. This is primarily because, in bipolar batteries, the currents flow in a direction perpendicular to the main extension directions of the carrier layers. This allows the use of a material with a significantly lower conductivity than the metal foils used in conventional batteries. In contrast to the M149PC2403

[0017] - 4 -conventional accumulators require the carrier layers to conduct the current essentially in directions where a large cross-section is available for the current conduction.

[0018] In practice, however, it is common to balance the individual cells of such a battery. This counteracts any differences in self-discharge behavior between the individual cells. Specifically, balancing prevents the charge levels of the individual cells from becoming increasingly disparate as the battery is used.

[0019] Balancing is achieved through equalizing currents controlled by a battery management system. While the currents required for this are lower than the currents flowing through the support layers perpendicular to their surface area during charging or discharging, they can be large enough to negatively impact the lower conductivity of support layers made of conductive plastics. This is particularly true when the support layers are very thin and have a comparatively large surface area, as is desirable with regard to current conduction during charging and / or discharging, as well as the battery's weight and required installation space.

[0020] The invention is therefore based on the objective of demonstrating a bipolar accumulator, a method for manufacturing such a bipolar accumulator, and a motor vehicle with such an accumulator or an accumulator manufactured according to such a method, in which the disadvantages described above do not occur or at least occur to a lesser extent than in the prior art.

[0021] The task is solved by providing a bipolar accumulator, a method for manufacturing such a bipolar accumulator, and a motor vehicle with such an accumulator or an accumulator manufactured according to such a method. M149PC2403

[0022] - 5 -accumulator with the features of the independent claims. The features of the dependent claims relate to advantageous embodiments.

[0023] The bipolar accumulator for storing electrical energy comprises multiple electrical cells. These cells are arranged in multiple layers. Each cell has an anode and a cathode, each mounted on a substrate layer. Between each pair of adjacent cells, a substrate layer is positioned, on which the anode of one of the two adjacent cells and the cathode of the other are mounted. The anode and cathode are electrically connected to each other through this substrate layer.

[0024] The substrate layer consists primarily of electrically conductive plastic. This substrate layer can be based on a plastic film. Plastic films are readily available and inexpensive from industrial production and possess good mechanical properties. Furthermore, processing plastic films is relatively straightforward. A substrate layer consisting primarily of electrically conductive plastic is defined as one that comprises at least 90% by volume of conductive plastic.

[0025] Plastics are primarily understood to be materials consisting mainly of macromolecules. These macromolecules are called polymers and can be of organic and / or inorganic origin, particularly based on hydrocarbons or silicon compounds, produced through polymerization. The plastic in question could be, for example, a polyolefin such as polypropylene or polyethylene.

[0026] Electrically conductive plastic can be a plastic containing an electrically conductive filler. This electrically conductive filler gives the plastic its electrical conductivity. The electrically conductive filler can be, for example, carbon. This can be present, in particular, in the form of carbon black. Carbon black as a filler for plastics is a proven and technologically well-controlled material. Carbon black makes it possible to produce conductive plastics. M149PC2403

[0027] - 6 - to be added. Alternatively and / or additionally, other fillers can also be used. These can also be made of carbon. For example, they can be carbon nanotubes.

[0028] As an alternative and / or supplement to plastics that have been made electrically conductive by the addition of electrically conductive fillers, the plastic can also be a plastic made of self-conducting polymers.

[0029] Self-conducting polymers are themselves conductive and therefore do not require fillers to exhibit sufficient conductivity.

[0030] The problem is solved, in particular, by the fact that the support layer comprises a metallic structure extending parallel to the support layer in a planar direction. Such a metallic structure can conduct the current in a direction parallel to the planar extent of the support layer. It has been shown that such a metallic structure can significantly improve the conductivity of the support layer in the direction parallel to its planar extent. Furthermore, it has been shown that introducing even relatively small amounts of metal into the support layer via the metallic structure can achieve an improvement in electrical conductivity that significantly enhances the battery's balancing performance. In particular, the voltage drop caused by the resistance of the support layer can be considerably reduced.This results in a more uniform balancing speed across the surface of each electrode. It has been shown that the high resistance of conventional carrier layers made of electrically conductive plastics means that the balancing process occurs faster near the electrical contact of the carrier layer than in areas of the electrode further away from the electrical contact. The metallic structure thus allows for a more uniform charge state across the electrode surface and / or reduces the time required for balancing.

[0031] The battery could be a lithium-ion battery. As described earlier, lithium-ion batteries require different M149PC2403

[0032] - 7 - Metals for metallic support layers. Insofar as the metallic structure comes into contact with the anode or cathode, this specific problem of lithium-ion batteries can be circumvented by selecting a suitable metal or several suitable metals. Care must simply be taken to ensure that the metallic structures do not come into contact with the anode or cathode materials in such a way that the unfavorable combinations of metals and the respective electrode material described above result. In this way, batteries can be created that combine the advantages of balancing with the advantages of lithium-ion batteries and the advantages of bipolar batteries.

[0033] The metallic structure can be a coating. In connection with the present invention, it has been shown that even relatively thin metallic layers are sufficient to improve the balancing of the accumulator. Therefore, applying coatings represents an economical solution for producing the support layers in question. The coating can be applied to one or both sides of the support layer's surface. The coating can be a full-surface and / or partial-surface coating. For example, it is possible to provide partial-surface patterns, such as grids. Alternatively and / or additionally, the metallic structures can also be arranged within a plastic layer of the support layer.

[0034] The process for manufacturing the bipolar accumulator can, in particular, provide for the metallic coating to be vapor-deposited onto a base layer of the support layer. Especially when the support layer is based on a plastic film, vapor deposition of the metallic coating onto a plastic film represents a particularly efficient way of realizing the support layer. The support layer based on a plastic film can, in particular, be realized by the base layer of the support layer being made of electrically conductive plastic. M149PC2403

[0035] - 8 - The metallic coating can have a thickness of at least 0.02 pm, in particular at least 0.05 pm, and / or at most 0.2 pm, in particular at most 0.1 pm. It has been shown that layers with thicknesses corresponding to the ranges specified above are sufficient to achieve an advantage with regard to balancing.

[0036] The substrate layer can have a thickness of at least 4 pm, in particular at least 6 pm, and / or at most 20 pm, in particular at most 10 pm. With substrate layers in this thickness range, sufficient stability of the accumulator can be achieved, while still ensuring a sufficiently low electrical resistance in the current flow direction perpendicular to the substrate layers for the operation of the accumulator. In particular, in combination with the specified thicknesses of the metallic coatings, a lightweight and efficient accumulator can thus be created.

[0037] A surface of the substrate layer on which the anode is applied and / or a surface of the substrate layer on which the cathode is applied can each have an area of ​​at least 1000 cm². 2 , in particular at least 2000 cm 2 , and / or a maximum of 30,000 cm² 2 , in particular a maximum of 10,000 cm 2 , exhibit. In particular, all surfaces of the substrate layers on which the anodes are applied and / or all surfaces of the substrate layers on which the cathodes are applied can each have an area of ​​at least 1000 cm². 2 , in particular at least 2000 cm 2 , and / or a maximum of 30,000 cm² 2 , in particular a maximum of 10,000 cm 2The described accumulators enable balancing of the accumulator even with the comparatively large areas of the substrate layers mentioned above. This allows for the realization of accumulators with large surface areas and thus high capacity, which can nevertheless be effectively balanced, even though the resulting current paths are comparatively long. In other words, the advantage of the metallic structures for improving conductivity in the direction parallel to the plane of the substrate layer is particularly evident with such large surface areas of the substrate layers. M149PC2403

[0038] - 9 - Furthermore, the accumulator includes, in particular, an electrolyte. The electrolyte is arranged, in particular, between the anode and the cathode. The electrolyte can be in the form of a liquid, a solid, and / or a gel. The electrolytes of individual cells can be separate from one another. Electrolytes in the form of a solid are also referred to as solid electrolytes. The solid electrolyte can, in particular, be based on a polymer, an inorganic oxide, and / or an inorganic sulfide. Such solid electrolytes, in conjunction with the accumulator described, have the particular advantage that the process step of filling with the electrolyte described below can be omitted, and consequently, no accumulator design features, such as the provision of the passages described below, are necessary.Furthermore, solid electrolytes are less flammable than liquid electrolytes and / or are non-flammable.

[0039] The bipolar battery may have individual cells sealed. This seal is specifically impermeable to the electrolyte and / or water vapor. An elastic seal has the advantage of compensating for cell expansion and / or contraction during charging and / or discharging. These expansions and contractions result from the transfer of material, such as lithium, from the cathode to the anode during charging, which causes the cathode to shrink or expand and the anode to expand. During discharge, the reverse process occurs: the material, such as lithium, is transferred from the anode to the cathode. During this process, the anode shrinks while the cathode expands.Since the expansion and / or contraction processes of the anode and the cathode have different characteristics with regard to the respective volume changes, these processes lead to the expansion and / or contraction of the entire cell during charging or discharging.

[0040] Advantageously, the edge regions of the carrier layers can be used to seal the cells. These are particularly compatible with other components of M149PC2403.

[0041] - 10 - Sealing, which may in particular be elastic polymers, combined.

[0042] A plastic carrier layer is ideally suited for bonding the cell to other parts of the seal, which can also be made of plastic. This bonding can be achieved using an adhesive. However, other bonding methods are also conceivable, such as welding the carrier layer to other components of the seal.

[0043] The carrier layers can have areas that protrude from the cell seal and can be used for contacting the individual cells by a battery management system. These areas can be designed as tabs or tongues. This allows the cells connected in series to be contacted individually for balancing purposes.

[0044] The seals of the individual cells may have sealed passages. Such passages allow the cells to be filled with electrolyte during the battery manufacturing process and / or for substances to be removed from inside the cell. These substances to be removed could, for example, be forming gases. However, these passages are sealed when the battery is operational.

[0045] The bipolar accumulator can be manufactured, in particular, by first applying a layer of electrode material to an auxiliary substrate. This layer of electrode material is then transferred to the substrate layer made of electrically conductive plastic in a later process step.

[0046] This process allows the respective electrode compound for the cathode or anode to be further processed on the sub-support. This has the advantage that the conductive plastic substrate layer is not affected during the processing steps carried out while the electrode compound is applied to the sub-support. In this way, the M149PC2403

[0047] - 11 - Processing of the electrode layer under process parameters that could not be applied if the processing were to take place on the conductive plastic substrate.

[0048] Once the electrode material layer is applied to the substrate, it can be further processed, particularly to create the electrode layer. This processing can include, in particular, thermal treatment. Thermal treatment can be used to remove additives, such as solvents or plasticizers, from the electrode layer.

[0049] Alternatively and / or additionally, while the electrode layer is being deposited on the support substrate, the electrode layer can be compacted, in particular by calendering.

[0050] Alternatively and / or additionally to applying the electrode compound to a substrate, the electrode compound can be applied directly to the substrate layer, for example via a slot nozzle. This can be done by first applying the electrode compound to one side of the substrate layer and further processing it into the electrode layer, for example by drying it, before repeating the process for the second electrode layer on the other side of the film. Alternatively, the electrode compound can be applied simultaneously to both sides of the substrate layer.

[0051] The electrode material can consist of a base material and a plasticizer as its main components. The base material contains, in particular, those components of the electrode material that form the electrode after the plasticizer is subsequently, at least partially, removed. The plasticizer can be removed before calendering. This leaves a porosity in the layer after the plasticizer is removed, which simplifies the calendering process.

[0052] The electrode material, especially the base material, contains an active material as a component. In the case of the anode, the active material can be, in particular, M149PC2403

[0053] - 12 -re may be graphite and / or, in the case of the cathode, lithium nickel manganese cobalt oxide, lithium nickel cobalt aluminum oxide, or lithium iron phosphate (LiFePCU). Other active materials, especially lithium compounds, are also conceivable. Active materials are defined as the chemically active substances in an electrode that are responsible for energy storage by undergoing chemical transformations involving the release and / or absorption of electrical charge carriers when the battery is charged and / or discharged.

[0054] The mass fraction of the active material to the base mass is at least 88% and / or at most 97%.

[0055] The electrode material, particularly the base material, may contain an additive to improve electrical conductivity. This additive may be, for example, carbon nanotubes, graphene, carbon black, expanded graphite, and / or graphite. The mass fraction of the additive in the base material may be at least 1% and / or at most 5%.

[0056] The electrode material, in particular the base material, may contain a binder. The binder may be a polymer, in particular a fluoropolymer. The mass fraction of the binder in the base material may be at least 1%, in particular at least 3%, and / or at most 7%, in particular at most 5%.

[0057] The electrode mass may also contain a plasticizer. The plasticizer may, for example, be a substance exhibiting suitable phase transition behavior. This includes, in particular, a substance whose melting point is at most 80 °C, especially at most 35 °C, and / or whose boiling point is at least 120 °C, especially at least 140 °C. Substances with such phase transition behavior are suitable for keeping the electrode mass in a plastic or flowable state, particularly during mixing or conveying through an extrusion die, while simultaneously being suitable for the formation of a stable layer, especially immediately after exiting the extrusion die.

[0058] - 13 -carrier, to ensure, in particular without risking gas formation during the process steps carried out at elevated temperature.

[0059] The mass fraction of the plasticizer can be selected based on the properties of the base material components. Parameters such as particle size, surface area, and the quantity and type of additives, such as binders and / or additives to improve electrical conductivity, can be taken into account. The quantity and type of active material also play a role. In this context, it has proven advantageous if, when graphite is used as the active material for the anode, the mass fraction of the plasticizer is at least 14%, particularly at least 20%, and / or at most 42%, particularly at most 40%. In the case of the cathode, particularly a lithium iron phosphate cathode, the mass fraction of the plasticizer can be at least 30%, particularly at least 35%, and / or at most 50%, particularly at most 42%.

[0060] In particular, the plasticizer could be ethylene carbonate. According to the prior art, ethylene carbonate is already used in the electrolytes of accumulators of the type in question and is therefore unproblematic for the accumulator, especially for its operation. Furthermore, due to its low melting point, ethylene carbonate exhibits temperature-dependent behavior. This allows the ethylene carbonate to act as a plasticizer at the temperatures prevailing during the production of the electrode mass, especially between the mixing device and the extrusion die. After the electrode mass cools on the substrate, particularly after cooling to room temperature, it loses, at least to a large extent, its plasticizing effect.

[0061] As an alternative to the electrode compound described above, which includes a base and a plasticizer, the electrode compound can be in the form of a paste, particularly a low-viscosity one, containing the electrode components and a solvent. The electrode components can be M149PC2403

[0062] - 14 - an active material, a conductivity additive, for example carbon black and / or a binder.

[0063] The solvent can be water. In this case, the binder can be, for example, carboxymethylcellulose or styrene-butadiene rubber. Alternatively and / or additionally, the solvent can be N-methyl-2-pyrrolidone. In this case, the binder can be, for example, polyvinylidene fluoride.

[0064] The mixing of the components and the solvent can be carried out, particularly in batches, in mixers such as planetary mixers. Alternatively and / or additionally, mixing can also be carried out, particularly continuously, using twin-screw extruders.

[0065] The method may involve cooling the electrode mass after it has been applied to the support. In particular, cooling to room temperature may occur.

[0066] The auxiliary carrier can be, in particular, a carrier made of a polymer material. The auxiliary carrier is, in particular, in the form of an elongated strip. This is moved, in particular, past an extrusion die while the electrode compound is applied to the auxiliary carrier. The auxiliary carrier can, in particular, be a polymer film. The polymer film can be a film made of polyethylene terephthalate (PET), polyetheretherketone (PEEK), or a polyimide. The auxiliary carrier can have a coating to facilitate the detachment of the electrode compound from the auxiliary carrier. The coating can, for example, be made of polytetrafluoroethylene (PTFE). The auxiliary carrier can, in particular, be stored on a roll from which it is unwound to be transported to the extrusion die.

[0067] The process can involve removing the plasticizer, at least to a large extent, from the electrode mass. In particular, this can create porosity in the electrode. The removal of the plasticizer can be achieved, in particular, by applying heat. The heat application can, in particular, be M149PC2403

[0068] - 15 - cause the plasticizer to evaporate. The heat can be generated, for example, by infrared heating. Preferably, the plasticizer is removed from the electrode mass while the electrode mass is applied to the auxiliary carrier.

[0069] To transfer the electrode material layer from the auxiliary carrier to the substrate layer, the electrode material layer can, in particular, first be applied to a transfer material. Here, the electrode material layer is transferred from the auxiliary carrier to the transfer material in such a way that the side of the electrode material layer facing away from the auxiliary carrier comes into contact with the transfer material. The transfer of the electrode material layer from the transfer material to the substrate layer is carried out in such a way that the side of the electrode material layer facing away from the transfer material comes into contact with the substrate layer. In this context, it is advantageous if the substrate layer is coated with an electrically conductive adhesion promoter before the electrode material layer is applied to the substrate layer.

[0070] In particular, the method can provide that the electrode material layer is divided into sections for the electrodes of the individual cells. The layer can be divided, in particular, using a laser. The division of the layer is carried out, in particular, while the layer is deposited on the support carrier and / or the transfer material. The transfer of the individual sections onto a transfer material and / or the carrier can be carried out, in particular, in a continuous process, for example, by roll-to-roll transfer.

[0071] In particular, two layers of electrode material, one of which is a layer of cathode material and the other of which is a layer of anode material, are applied such that each layer of electrode material is applied to one side of the support layer. The application is carried out for each of the two layers in the manner described above. M149PC2403

[0072] - 16 -

[0073] Once the electrode material layers are applied to the substrate layer, a plurality of correspondingly coated substrate layers are arranged one above the other in multiple layers to form the corresponding plurality of cells. The coated substrate layers are arranged in such a way that the anode material layer on one substrate layer faces the cathode material layer of an adjacent substrate layer.

[0074] After the substrate layers have been arranged, the cells can be sealed. This sealing is achieved, in particular, by bonding the edge areas of the substrate layers, which are not covered with the electrode material layer, with other components of the sealant.

[0075] The seal, and in particular its other components, may have openings. These openings can be used to fill the otherwise sealed cells with electrolyte. A liquid electrolyte is particularly suitable for filling the individual cells. After filling the cells with electrolyte, the opening used for this purpose is preferably closed. This can be achieved, for example, by fusing the opening. The other components of the seal, especially in the area of ​​the opening, may be made of polypropylene.

[0076] It is possible that the openings are initially closed after the seal is applied and are opened during filling. For this purpose, the openings may have a barrier that is pierced by a suitable tool, such as a dispensing needle used for filling.

[0077] Each cell can have multiple such openings. This allows for a more uniform filling of the respective cell. In particular, due to the small thickness of the cell, which is preferably at least 100 pm and / or at most 600 pm, and preferably at most 400 pm, a more uniform filling of the cell can be achieved.

[0078] - 17 - Filling the thin gap between the layers of electrode material with the electrolyte is ensured. The electrolyte can, in particular, be filled into one passage of the cell in such a way that it exits again through another passage, preferably spaced apart from the one used for filling. Such a "flushing" of the cell with the electrolyte during filling can ensure that the cell is completely filled.

[0079] Furthermore, the passages can be used to degas the cell.

[0080] The electrolyte used to fill the individual cells can be a liquid electrolyte. This electrolyte may contain an organic solvent. In particular, the organic solvent may be a carbonate, such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, acetonitrile, and / or ethyl methyl carbonate.

[0081] Furthermore, the solvent may contain a conducting salt, such as LiPFe. Additionally, the electrolyte may contain at least one additive, such as vinylene carbonate. This additive may serve, in particular, to stabilize a protective layer on the anode, the so-called SEI (Solid Electrolyte Interface).

[0082] The motor vehicle includes a bipolar accumulator corresponding to the above description and / or manufactured according to the above-described method. The described bipolar accumulator is particularly suitable for use in motor vehicles due to the advantages of the bipolar concept, namely the associated good space utilization and / or the comparatively low weight in relation to the accumulator's power and / or capacity.

[0083] The support layers can be aligned, at least substantially, parallel to a plane spanned by the longitudinal and transverse directions of the motor vehicle. In other words, the support layers in the vehicle's operating condition can be aligned parallel to a plane spanned, at least substantially, by M149PC2403

[0084] - 18 -horizontal plane. While such an orientation of the support layers enables batteries that, due to the bipolar concept, exhibit good space utilization, the comparatively large surface areas of the support layers resulting in typical automotive installation situations lead to long current paths when balancing the battery. Therefore, the metallic structures, especially with such an orientation of the layers in the vehicle, offer advantageous possibilities for designing and arranging the battery.

[0085] The battery can be located in the underbody of the vehicle. This is particularly advantageous because it results in a low center of gravity. Furthermore, the underbody offers a comparatively large installation space. The resulting batteries exhibit a relatively large extent in both the longitudinal and transverse directions of the vehicle compared to their thickness. Especially in conjunction with the horizontally oriented support layers described above, this allows for the realization of batteries with a large surface area for each support layer, where the improved conductivity provided by the metallic structures, and particularly by the coatings on the support layers, can be advantageously utilized.

[0086] Further practical embodiments and advantages of the invention are described below in connection with the drawings. They show:

[0087] Fig. 1 shows a schematic representation of the multi-layered arrangement of the electrical cells of an exemplary accumulator,

[0088] Fig. 2 shows a schematic representation of the sealing of the individual cells of an exemplary accumulator,

[0089] Fig. 3 shows a schematic representation of a substrate layer coated with electrode material of an exemplary accumulator, M149PC2403

[0090] - 19 -

[0091] Fig. 4 shows a schematic sectional view of a section of an exemplary carrier layer,

[0092] Fig. 5 shows a schematic sectional view of a section of an exemplary carrier layer according to a further embodiment.

[0093] The exemplary accumulator 10 comprises a plurality of cells 12. These cells—with the exception of cells 12a and 12c, which are the outermost cells 12 in the multilayer structure of the accumulator 10—are arranged between two carrier layers 14 made of electrically conductive plastic. In the illustration in Figure 1, the accumulator 10 is shown in a simplified form for clarity. The cells 12d correspond in their structure to the fully illustrated cell 12b.

[0094] Each of the cells 12 has a layer of cathode material 16 and a layer of anode material 18. A separator 20 is arranged between each of the electrode material 16 and anode material 18 layers. Each of the cells 12 is filled with an electrolyte, in particular a liquid electrolyte. This electrolyte is located, in particular, in the pores of the electrodes 16 and 18 and of the separator 20 (not shown in detail). As in the example shown, the outermost electrode layers of the multilayer structure can be applied to a metal layer instead of a support layer 14. This metal layer can, in particular, be a cathode support layer 22 made of aluminum and / or an anode support layer 24 made of copper.

[0095] As shown in Figure 2, the individual cells of the accumulator 10 can have a seal 26. The seal 26 is, in particular, connected to areas of the support layers 14, and thus forms a completely enclosing seal around the other components of the respective cell 12 arranged between the support layers 14, in particular the cathode material layer 16, the anode material layer 18, and the separator 20. M149PC2403

[0096] - 20 - As shown in Figure 2, the individual cells 12 can have openings 28 in the seal 26 which can be used to fill the electrolyte into the respective cell 12.

[0097] Figure 3 shows an example of a support layer 14. This layer is coated on each side with a layer of electrode material 16 or 18. One side of the support layer 14 has a layer of cathode material 16, and the other side of the support layer 14 has a layer of anode material 18.

[0098] The carrier layer 14 can, as in the example shown, have an edge region 30 that is not coated with electrode material. This edge region 30 can be used for sealing the individual cells 12 by connecting the edge region 30 with other areas of the seal 26 (see Figure 2).

[0099] Figure 4 schematically illustrates an example of a section of a support layer 14. The support layer 14 can, as in the example shown, consist largely of electrically conductive plastic. This electrically conductive plastic can form a base layer 34. The base layer 34 can, as in the example shown, be a plastic film made of an electrically conductive plastic.

[0100] The carrier layer 14 comprises a metallic structure extending parallel to the carrier layer 14 over a planar area. As in the example shown, the metallic structure can be a coating 36. As in the example shown, the carrier layer 14 can have a metallic coating 36 on both sides.

[0101] Alternatively, the carrier layer 14 can have a metallic structure in the form of a coating 36 on only one of its sides. A section of such an exemplary carrier layer 14 is shown schematically in Figure 5. The carrier layer 14 shown as an example in Figure 5 also has a base layer 34 in M149PC2403.

[0102] - 21 - Shape of a plastic film made of electrically conductive plastic. The coating 36 can also be vapor-deposited in this example shown.

[0103] In particular, the carrier layer 14 can have areas 32 that protrude from the seal 26. These areas can be used, in particular, for contacting the individual cells 12 by a battery management system.

[0104] The features of the invention disclosed in the present description, the drawings, and the claims can be essential for realizing the invention in its various embodiments, both individually and in any combination. The invention is not limited to the described embodiments. It can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. M149PC2403

[0105] - 22 - List of reference symbols

[0106] 10 Accumulator

[0107] 12 cells

[0108] 14 support layers

[0109] 16 Cathode mass

[0110] 18 Anode mass

[0111] 20 Separator

[0112] 22 Cathode support layer

[0113] 24 Anode support layer

[0114] 26 Sealing

[0115] 28 passages

[0116] 30 Edge area

[0117] 32 area

[0118] 34 Base layer

[0119] 36 coating

[0120] * * * * * * *

Claims

M149PC2403 - 23 - Patent claims 1. Bipolar accumulator (10), in particular a bipolar lithium-ion accumulator (10), for storing electrical energy, wherein a plurality of electrical cells (12) are arranged in multiple layers one above the other, wherein each cell (12) has an anode and a cathode, each of which is applied to a support layer (14), wherein a support layer (14) is arranged between each pair of adjacent cells (12), on which the anode of one of the two adjacent cells (12) and the cathode of the other of the two adjacent cells (12) is applied, and the anode and the cathode are electrically connected to each other by the support layer (14), wherein the support layer (14) is made mostly of electrically conductive plastic, characterized by that the support layer (14) comprises a metallic structure extending over a surface parallel to the support layer (14).

2. Bipolar accumulator (10) for storing electrical energy according to claim 1, characterized in that the support layer (14) is based on a plastic film.

3. Bipolar accumulator (10) for storing electrical energy according to one of the preceding claims, characterized in that the metallic structure is a metallic coating (32).

4. Bipolar accumulator (10) for storing electrical energy according to one of the preceding claims, characterized in that the metallic coating has a thickness of at least 0.02 pm, in particular at least 0.05 pm, and / or at most 0.2 pm, in particular at most 0.1 pm.

5. Bipolar accumulator (10) for storing electrical energy according to one of the preceding claims, wherein the support layer (14) has a thickness of slightly- M149PC2403 - 24 - tens 4 pm, in particular at least 6 pm, and / or at most 20 pm, in particular at most 10 pm, has.

6. Bipolar accumulator (10) for storing electrical energy according to one of the preceding claims, wherein a surface of the support layer (14) on which the anode is applied and / or a surface of the support layer (14) on which the cathode is applied each has an area of ​​at least 1,000 cm². 2 , in particular at least 2,000 cm 2 , and / or a maximum of 30,000 cm² 2 , in particular a maximum of 10,000 cm 2 , exhibits.

7. Bipolar accumulator (10) for storing electrical energy according to one of the preceding claims (14), characterized in that the support layers (14) of the cells extend in planes parallel to each other.

8. Bipolar accumulator (10) for storing electrical energy according to one of the preceding claims, characterized in that the electrically conductive plastic is a plastic comprising an electrically conductive filler, in particular carbon.

9. Bipolar accumulator (10) for storing electrical energy according to one of the preceding claims, characterized in that the accumulator (10) has a sealing (26) of the cells (12), in particular wherein edge areas (30) of the carrier layers (14) are used for sealing (26) the cells (12).

10. Bipolar accumulator (10) for storing electrical energy according to claim 4, characterized in that the support layers (14) have areas (32) which protrude outwards from the sealing (26) of the cells (12) and can be used for contacting the individual cells by a battery management system.

11. Bipolar accumulator (10) for storing electrical energy according to claim 4 or 5, characterized in that the seals (26) of the individual cells (12) have sealed passages (28). M149PC2403 - 25 - 12. Method for producing a bipolar accumulator (10) for storing electrical energy according to one of claims 3 to 11, characterized in that the metallic coating (32) is vapor-deposited onto a base layer (34) of the carrier layer (14).

13. Motor vehicle with a bipolar accumulator according to one of claims 1 to 11 or a bipolar accumulator (10) produced by a method according to one of claims 12.

14. Motor vehicle according to claim 13, characterized in that the support layers (14) are aligned, at least substantially, parallel to a plane spanned by the longitudinal direction and the transverse direction of the motor vehicle.

15. Motor vehicle according to claim 13 or 14, characterized in that the accumulator (10) is arranged in the area of ​​the underbody of the motor vehicle. * * * * * * *

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