DE102022204285A1 - Battery cell - Google Patents

Abstract

The invention relates to a battery cell (14) with a cell stack (20), which has a plurality of anodes (16) and cathodes (18) stacked alternately one above the other in a stacking direction (23), between each of which a separator (22) is arranged. The cell stack (20) is completely non-positively wrapped around the circumference with a band (26). The invention further relates to a method (34) for producing a battery cell (14).

Description

The invention relates to a battery cell and a method for producing a battery cell. The battery cell has a cell stack which comprises a plurality of anodes and cathodes stacked alternately one above the other in a stacking direction, between each of which a separator is arranged.

Increasingly, motor vehicles are at least partially driven by an electric motor, so that they are designed as electric vehicles or hybrid vehicles. A high-voltage battery, which includes several individual battery modules, is usually used to power the electric motor. The battery modules are usually identical to one another and are connected electrically in series and/or parallel, so that the electrical voltage applied to the high-voltage battery corresponds to a multiple of the electrical voltage provided by each of the battery modules. Each battery module in turn comprises several battery cells, which are usually arranged in a common module housing and which are electrically connected to one another in series and/or parallel.

Each of the battery cells in turn usually includes several galvanic elements. These each have two electrodes, namely an anode and a cathode, as well as a separator arranged between them and an electrolyte with freely movable charge carriers. A liquid, for example, is used as such an electrolyte. In an alternative, the battery cell is designed as a solid-state battery and the electrolyte is in the form of a solid. The anode and cathode, which form the electrodes of the battery cell, usually include a carrier that acts as a current collector. An active material is usually attached to this, which is part of a layer applied to the carrier, which is also referred to as an arrester. It is possible that the electrolyte is already present in the layer, or it is introduced later. However, at least the active material is suitable for absorbing the working ions, e.g. lithium ions. Depending on the use as an anode or cathode, a different material is used for the carrier and a different type of material of the layer.

To protect the galvanic elements, they are usually arranged in a cell housing of the battery cell, which includes, for example, a cell cup closed with a lid. The cell housing also protects the electrolyte from environmental influences. So that a comparatively large capacity is provided by the respective battery cell, several such galvanic elements are usually arranged in the common cell housing. In order to use the available space comparatively efficiently and to simplify production, the individual components of the galvanic elements are designed to be flat and stacked one above the other in a stacking direction, so that a substantially cuboid cell stack is formed.

To stabilize the individual components of the cell stack, adhesive strips are usually provided, which are guided along one of the long sides of the cell stack and surround the edge of the cell stack. In order for the middle layers of the cell stack to be stabilized, it is necessary that the adhesive strips are installed to form a frictional connection. This leads to a local deformation of the cell stack and thus to a weakening in this area. With a higher load during operation, it is possible that the cell stack or at least some of the anodes or cathodes are charging there.

In addition, so that the anodes, cathodes and separators arranged between the ends of the cell stack are held comparatively securely, several such adhesive strips are assigned to each longitudinal side of the cell stack. Due to the large number of adhesive strips, the production time is extended. It is also necessary to position the adhesive strips comparatively precisely, which makes production more difficult. In addition, due to the maximum force that can be applied using the adhesive strips, a maximum number of layers of the cell stack is limited. If an increased capacity of the battery cell is to be provided, it is necessary to use several such cell stacks, which are stabilized relative to one another by means of the adhesive tapes. The cell stacks, in turn, are held together by additional adhesive strips, which further complicates production.

The invention is based on the object of specifying a particularly suitable battery cell and a particularly suitable method for producing a battery cell, advantageously material and/or manufacturing costs being reduced, suitably manufacturing being simplified, and in particular operational reliability being increased.

With regard to the battery cell, this task is solved according to the invention by the features of claim 1 and with regard to the method by the features of claim 8. Advantageous further developments and refinements are the subject of the respective subclaims.

The battery cell, which is hereinafter referred to in particular simply as a battery, is preferably designed to be rechargeable and preferably a secondary battery. Preferably, the battery cell is a component of a motor vehicle in its intended condition. The battery cell is suitable for this, in particular intended and set up. In the intended state, the battery cell is, for example, a component of an energy storage device of the motor vehicle, which has several such battery cells. The battery cells are preferably divided into several battery modules, which in turn are structurally identical to one another. The battery cells are arranged in particular in a housing of the energy storage or the respective battery module and are electrically connected in parallel and/or in series with one another. The electrical voltage applied to the energy storage/battery module is therefore a multiple of the electrical voltage provided by each of the battery cells. All battery cells are expediently identical in construction, which simplifies production.

The housing of the energy storage or the respective battery module, which thus in particular forms a composite of such battery cells, is preferably made of a metal, for example a steel, such as stainless steel, or an aluminum alloy. For example, a die-casting process, deep-drawing process, casting molding or extrusion molding is used for production. In particular, the housing of the energy storage or the respective battery module is designed to be closed. An interface is expediently incorporated into the housing of the energy storage or the respective battery module, which forms, for example, a plug of the energy storage/battery module. The interface is electrically contacted with the battery cells, so that electrical energy can be fed in and/or electrical energy can be withdrawn from the battery cells from outside the energy storage, provided that a corresponding mating connector is plugged into the plug.

The motor vehicle is, for example, a ship or boat. Preferably, however, the motor vehicle is land-based and preferably has a number of wheels, at least one of which, suitably several or all of them, are driven by means of a drive. In particular, one, preferably several, of the wheels is designed to be controllable. This makes it possible to move the motor vehicle independently of a specific roadway, for example rails or the like. It is expediently possible to position the motor vehicle essentially anywhere on a road that is made in particular from asphalt, tar or concrete. The motor vehicle is, for example, a commercial vehicle, such as a truck or a bus. However, the motor vehicle is particularly preferably a passenger car (car).

The motor vehicle is expediently moved by means of the drive. For example, the drive, in particular the main drive, is at least partially designed to be electrical, and the motor vehicle is, for example, an electric vehicle. The electric motor is operated, for example, by means of the energy storage device, which is suitably designed as a high-voltage battery. An electrical direct voltage is expediently provided by means of the high-voltage battery, the electrical voltage being, for example, between 200 V and 800 V and, for example, essentially 400 V. Preferably, an electrical converter is arranged between the energy storage device and the electric motor, by means of which the current supply to the electric motor is adjusted. In an alternative, the drive also has an internal combustion engine, so that the motor vehicle is designed as a hybrid motor vehicle. In an alternative, a low-voltage electrical system of the motor vehicle is fed by means of the energy storage, and in particular an electrical direct voltage of 12 V, 24 V or 48 V is provided by means of the energy storage.

In a further alternative, the battery cell is a component of an industrial truck, an industrial plant, a hand-held device, such as a tool, in particular a cordless screwdriver. In a further alternative, the battery cell is a component of an energy supply and is used there, for example, as a so-called buffer battery. Here, the battery cell is used, for example, within a power plant or a household/industrial facility. In a further alternative, the battery cell is a component of a portable device, for example a portable cell phone or a wearable, or a computer. It is also possible to use such a battery cell in camping, model building or other outdoor activities.

The battery cell has several anodes and cathodes, which in particular form the electrodes of the battery cell. It is particularly preferred that all anodes and all cathodes are identical in construction, which simplifies production. The electrodes, i.e. the anodes and the cathodes, are designed to be flat and in particular essentially rectangular. The anodes and cathodes each expediently have a carrier, which is also referred to as an arrester. In particular, the respective carrier is formed by means of a metal foil which is coated at least in sections with a layer on one or both sides. As the metal of the carrier/conductor of the cathodes For example, aluminum is used and copper is used as the metal for the anode arrester.

The layer has a thickness of less than 1 mm. The carriers expediently have a thickness of less than 0.1 mm. The respective layer preferably has an active material, a binder and/or a conductive additive, such as conductive carbon black. The active material is used to absorb working ions, such as lithium ions, and is suitable, intended and set up for this purpose. The active material used for the cathode is, for example, a lithium metal oxide, such as lithium cobalt (III) oxide (LiCoO2), NMC, for example NMC622 or NMC811, NCA or LFP, and/or LTO or graphite, Si for the anode. based, used.

The electrodes, i.e. the anodes and cathodes, are stacked one above the other to form a cell stack, the stacking direction being perpendicular to the direction of expansion of the electrodes, which are arranged parallel to one another. The anodes and cathodes alternate in the stacking direction of the cell stack. A separator of the cell stack is arranged between adjacent electrodes, that is to say between one of the anodes and one of the cathodes, which is preferably also designed to be flat. For example, all separators are identical to one another. In particular, the electrodes are stacked essentially flush one above the other, with all anodes, for example, protruding at least slightly beyond the cathodes. This avoids undesirable material accumulation on the edge regions of the anodes. Due to the stacking of the electrodes, the cell stack is also essentially cuboid-shaped.

The battery cell also has a band by means of which the cell stack is completely wrapped around the circumference in a non-positive manner. In other words, the band lies non-positively against the cell stack, with a force being exerted on the cell stack, for example, by means of the band. Alternatively, the band lies at least flat against the cell stack, with at least the formation of folds or the like in the band being ruled out due to the force-fitting contact. The band is expediently designed to be flat and completely surrounds the cell stack on the circumference. The band is therefore essentially band-shaped or hollow cylindrical. In particular, the band extends around the ends of the cell stack in the stacking direction, and around two sides of the cell stack that are opposite perpendicular to the stacking direction. The other two opposite sides of the cuboid cell stack are in particular free of the band. In this way, assembly and/or arrangement of the band is simplified. In summary, the cell stack is surrounded on the outside by means of the band. Preferably, the band lies mechanically directly against the cell stack, so that no further components are present between the band and the cell stack.

Due to the band, the cell stack, i.e. the anodes, cathodes and separators, is stabilized relative to one another, with the force-fitting system preventing any unwanted detachment of the band from the cell stack. On the other hand, in this way the anodes and cathodes as well as separators are suitably aligned with one another. Production is therefore simplified. While maintaining robustness, it is also possible to form a comparatively large cell stack in the stacking direction, which is why the energy density or at least capacity of the battery cell is increased. The alignment and fastening to one another using the band is also carried out in one work step, which is why production time and costs are reduced. Since only comparatively few components are required, material costs are reduced. Because the band completely wraps around the cell stack, force is exerted over a large area on the cell stack by means of the band. In other words, a local application of force is prevented, which would otherwise lead to excessive one-sided loading of the cell stack or an undesirable deformation of the cell stack. The cell stack is therefore not weakened on one side and operational reliability is increased. In addition, it is possible in this way to arrange the anodes and cathodes as well as separators alternately one above the other, and it is not necessary to deviate from this arrangement. In other words, no additional stabilization components are required. The energy density of the battery cell is therefore increased, and the cell stack can have a comparatively large number of anodes and cathodes.

For example, the band is designed to be inelastic. Particularly preferably, however, the band is at least partially designed in the manner of a compression band and for this purpose, for example, is at least slightly elastically deformable. By means of the elastic deformation, in particular, the force-fitting contact with the cell stack takes place, so that it is stabilized comparatively safely, with no additional components being required. In this way, tolerance compensation can also be achieved. In particular, the battery cell or the cell stack has no further components by means of which the anodes, cathodes and separators are stabilized relative to one another. As a result, material costs are reduced. The cell stack is preferably free of adhesive strips.

The battery cell expediently comprises a housing within which the cell stack is arranged. The band is conveniently located with its outside on the housing, so that the cell stack is further stabilized by means of the band by means of the housing. Due to the direct system, the energy density in the battery cell is further increased.

In particular, the housing is designed to be electrolyte-tight, so that any electrolyte in the battery cell is securely held within it. The housing preferably has one or two openings through which a connection is guided, the area between the connections and the edge of the respective opening also expediently being designed to be fluid-tight. Preferably, one of the connections is electrically contacted with at least one of the anodes and the other with one of the cathodes, so that the connections allow electrical energy to be fed in and/or electrical energy to be withdrawn from the cell stack from outside the housing. For example, the housing is designed to be rigid and, for example, cylindrical or cuboid-shaped. In other words, the battery cell is a prismatic (battery) cell. The housing is preferably made of aluminum. Alternatively, the housing is made of a film, for example, and the battery cell is designed as a so-called pouch cell. A coated metal foil is expediently used as the foil.

For example, the ends of the cell stack are only partially covered in the stacking direction by means of the band. However, the band is particularly preferably designed in such a way that the two ends of the cell stack are covered over their entire surface in the stacking direction by means of the band. In particular, the band is arranged flush with the cell stack. Consequently, the width of the band is equal to the width of the anodes, cathodes or separators. Thus, a force due to the non-positive audio system is exerted on a comparatively large area of the cell stack by means of the band, which leads to further equalization. This also prevents the anodes/cathodes/separators from moving among themselves. Furthermore, using the band it is possible to press the anodes, cathodes and separators together with a comparatively large force, which is why the energy density is increased. This also results in improved electrical contact between them.

For example, the cell stack has as many anodes as cathodes. However, the cell stack particularly preferably has one more anode than cathodes, so that each end of the cell stack is formed in the stacking direction by means of one of the anodes. Due to the additional anode, the energy density of the battery cell is further increased. There is also no need for an additional separator to cover the anodes, as this is done by the bands. Material and manufacturing costs are therefore further reduced.

For example, the anodes and cathodes as well as separators are separate from one another and are stacked on top of each other to form the cell stack. In other words, individual sheets are used to create the cell stack. Alternatively, for example, all separators are formed by means of a common separator belt that is folded several times in a Z shape. For example, the anodes and cathodes, which are designed in a leaf shape, are inserted into the individual folds. Alternatively, the separator belt is coated with the anodes and/or cathodes. By means of the band, which is wrapped around the Z-shaped folded separator band with the electrodes, the cell stack formed in this way is prevented from rolling off. Alternatively, the cell stack has several sub-stacks, with each of the sub-stacks being assigned a separator belt that is folded in a Z-shape. The individual partial stacks are each stabilized by means of a respective band or by means of other components. The partial stacks are stacked one above the other to form the cell stack, with the partial stacks being stabilized relative to one another by means of the band, by means of which the partial stacks are wrapped around.

However, the cell stack particularly preferably has a plurality of monocells stacked one on top of the other, each of the monocells consisting of one of the anodes, one of the cathodes and two of the separators. Each of the monocells forms in particular a galvanic element, and the monocells are preferably identical to one another. Preferably, the anode, the cathode and the separators of each monocell are attached to one another, for example by lamination or gluing. In other words, each of the monocells is designed to be particularly stable. On the one hand, due to the use of monocells, producing the cell stack is simplified. On the other hand, the cell stack is already partially stabilized in this way, and the monocells are aligned with one another and stabilized with respect to one another by means of the band. Consequently, manufacturing is further simplified. In this way it is also possible to manufacture the mono cells independently of the battery cell. The number of monocells desired for the respective battery cell is then selected from the monocells. Production is therefore further simplified. For example, the cell stack is formed only by means of the monocells, or particularly preferably the cell stack only has the monocells and an additional anode, so that the ends of the cell stack in the stacking direction are each formed by one of the anodes.

In particular, the band is designed to be flat and expediently has a thickness between 2 mm and 0.1 mm or between 1 mm and 0.5 mm. This means that the space requirement is reduced, while still maintaining robustness. The band is particularly preferably made of an electrically insulating material. In this way, it is possible to attach the cell stack to other components of the battery cell via the band, with the band preventing an electrical short circuit. In particular, in the assembled state, the band lies mechanically directly on an inside of any housing of the battery cell, which is why manufacturing costs are reduced and energy density is increased. In summary, the tape also acts as an electrical insulator, so that safety is increased.

Alternatively or particularly preferably in combination with this, the material is permeable to electrolytes, i.e. in particular permeable to the electrolyte used in each case. This means that the function of the galvanic elements is not affected by the band. In summary, a capacity of the cell stack or an internal resistance is not changed by means of the band, thus a construction is simplified and a range of use is increased.

Particularly preferably, the material used for the band is the same material from which the separators are made. This means that the number of different materials is limited, which is why undesirable chemical reactions are avoided. Manufacturing costs are also reduced. The band is particularly preferably designed to be thicker than the separators. In this way, assembly of the band is simplified and robustness is increased. The material used is preferably polyethylene (PE) or polypropylene (PP). This means that material costs for the battery cell are further reduced.

Particularly preferably, the material from which the band is made has a swelling behavior, so that its volume increases in particular when the band is exposed to an electrolyte or another liquid. Due to the swelling, a force connection to the cell stack is increased. For example, the frictional connection only occurs due to the swelling, which is why assembly is simplified. However, at least the adhesion is improved due to the swelling. This means that the individual components of the cell stack are reliably prevented from becoming detached by means of the band.

For example, the band is made in one piece and the cell stack is inserted into it. However, it is particularly preferred that the two ends of the band are initially separated and are only joined together during assembly. For example, these abut one another and are appropriately fastened to one another, for example by welding. However, it is particularly preferred that the two ends overlap, which is why the connection is more robust. Conveniently, the area of the overlap is equal to the size of the side on which the overlap is located, so that there is no step due to the overlap.

In this way, the band enables the force to be applied evenly to the cell stack and localized overloading is avoided. The overlap is particularly preferably located at one of the ends of the cell stack in the stacking direction. In this way, when the two ends of the band are fastened to one another, force is applied to the cell stack in the stacking direction, and displacement of the anodes/cathodes and separators is avoided in this way. This also increases the compactness of the cell stack. Alternatively, the overlap is arranged on a perpendicular side surface of the cell stack.

For example, the two ends of the band are connected in the area of the overlap by welding. However, it is particularly preferred that the two ends of the band are attached to one another using adhesive, in particular the adhesive is applied along the complete overlap. Due to the overlap, a force acting on the ends of the band due to the frictional connection with the cell stack is evened out, so that the two ends are prevented from becoming detached, even with a comparatively weak adhesive. In other words, it is possible to use an adhesive with a comparatively weak adhesion, but the two ends are still securely connected to one another due to the large overlap and the large adhesive surface. However, due to the comparatively weak adhesive, material costs are reduced. It is also possible, for example, to dismantle or correct the band in this way. For example, the adhesive is only present in the area of the overlap, which is why material costs are reduced. Alternatively, the inside of the band is completely provided with adhesive, so that the band is also stuck to the cell stack. In this way, robustness is further increased. Alternatively, the inside of the tape is only provided with the adhesive in spots or strips. Material requirements are therefore reduced, while robustness is nevertheless increased.

The separators particularly preferably protrude over the edges of the anodes and cathodes. In this way, a short circuit is created between the anodes and cathodes by means of the separators and connected. The ends of the separators are expediently bent in the stacking direction using the band. The band therefore rests mainly on the separators, and the force connection takes place via these, which is why the load acting on the anodes or cathodes is reduced. In particular, the ends of the separators are bent parallel to the stacking direction, so that the separators have a 90° bend on the edge. Particularly preferably, the opposite edges of each separator are bent in the same direction, so that each separator is essentially U-shaped. Consequently, stability is increased and production is simplified. Due to the bending, the separators partially form the sides of the cell stack and by means of this the anodes and cathodes are at least partially separated from the band. The separators are particularly preferably bent in such a way that adjacent separators rest against one another. This means that at least the middle anodes and cathodes are also wrapped around the edges by means of the separators, which is why, on the one hand, penetration of foreign particles is avoided there. This also prevents a short circuit. It is therefore possible, for example, to manufacture the band from an electrically conductive material, with an electrical short circuit to the anodes and cathodes being avoided due to the bent separators.

The method for producing a battery cell with a cell stack, which has a plurality of anodes and cathodes stacked alternately one on top of the other in a stacking direction, between each of which a separator is arranged, and which is completely non-positively wrapped around the circumference with a band, provides that the band is initially provided flat becomes. In other words, the band is positioned in such a way that it covers an area. In particular, the band is essentially arranged only in a flat plane and thus essentially two-dimensionally. The band preferably has no wrinkles or other unevenness.

In a further step, the cell stack, which has the anodes and cathodes stacked alternately one on top of the other in the stacking direction, between which one of the separators is arranged, is stacked on the belt. In other words, the cell stack is arranged on the belt. For example, the cell stack is already prefabricated and is available as a unit. Alternatively, the individual components of the cell stack are layered onto the belt to create the cell stack. In particular, the stacking direction is perpendicular to the plane in which the strip is provided flat. In other words, one of the ends of the cell stack is placed on the belt in the stacking direction and the other components of the cell stack (initially) have no contact with the belt. The cell stack is particularly preferably stacked in such a way that an anode is first arranged on the belt, in particular mechanically directly. Particularly preferably, the other end of the cell stack is also formed by means of an anode.

For stacking, for example, if the cell stack is not yet prefabricated, the individual components, for example the anodes, cathodes and separators, are stacked individually on the belt, or these are already partially combined to form monocells, which are thus arranged on the belt. For example, if mono cells are used, a single anode is first arranged on the strip, onto which the mono cells are then stacked. In an alternative to this, for example, the monocells are stacked directly onto the strip, and finally a single anode is placed on one of the monocells, which thus forms the opposite end of the cell stack in the stacking direction.

In particular, the cell stack or at least some components of the cell stack are stacked on the belt in such a way that it is flush on opposite sides with a respective assigned edge of the belt. In other words, the cell stack or at least part of the cell stack has the same width as the band. This means that the cell stack does not tilt due to unevenness, which would be caused by a shortened width of the belt. Particularly preferably, the cell stack is arranged essentially centrally between the ends of the flatly stretched band. This makes positioning and later further processing easier.

In a subsequent step, the band is wrapped around the circumference of the cell stack in a force-fitting manner. The band then completely surrounds the cell stack on the circumference. Here, the band is, for example, bent or folded at the edges of the cell stack. The bending/folding is preferably carried out using a corresponding device, by means of which, for example, the cell stack is also rotated and/or the battery cell is transported away. Particularly preferably, the ends of the band are fastened to one another so that the cell stack is held in a force-fitting manner by means of the band. Preferably, the band is glued, and when the two ends are glued or otherwise fastened to one another, the band is particularly attached to the cell stack Force exerted in stacking direction. This means that the cell stack is additionally compacted in the step in which the band is glued/the ends are attached to one another. Manufacturing time is therefore shortened. Preferably, the band with the cell stack is subsequently arranged in a housing which is made, for example, from aluminum.

The invention further relates to a composite of such battery cells, the composite preferably being a battery module or a high-voltage battery. The invention further relates to a motor vehicle, such as a passenger car, with such a battery cell, in particular such a composite. The battery cell is preferably used to power a main drive of the motor vehicle.

The advantages and developments described in connection with the battery cell can also be applied analogously to the process/the network/the motor vehicle and to each other and vice versa.

• 1 schematisch vereinfacht ein Kraftfahrzeug, das mehrere baugleiche Batteriezellen aufweist,
• 2 schematisch in einer Schnittdarstellung eine der Batteriezellen,
• 3 ein Verfahren zur Herstellung der Batteriezelle,
• 4 - 7 die Batteriezelle in unterschiedlichen Stadien der Herstellung, und
• 8-10 jeweils gemäß 2 weitere Varianten der Batteriezelle.

Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. Show in it:

• 1 schematically simplified a motor vehicle that has several identical battery cells,
• 2 schematically in a sectional view of one of the battery cells,
• 3 a process for producing the battery cell,
• 4 - 7 the battery cell in different stages of production, and
• 8-10 each according to 2 further variants of the battery cell.

Corresponding parts are provided with the same reference numbers in all figures.

In 1 A motor vehicle 2 is shown in a schematically simplified form in the form of a passenger car (car). The motor vehicle 2 has a number of wheels 4, at least some of which are driven by a drive 6 which includes an electric motor. The motor vehicle 2 is therefore an electric vehicle or a hybrid vehicle. The drive 6 has a converter, by means of which the electric motor is fed. The converter of the drive 6 is in turn powered by an energy storage device 8 in the form of a high-voltage battery. For this purpose, the drive 6 is connected to an interface 10 of the energy storage 8, which is inserted into an energy storage housing 12 of the energy storage 8, which is made of stainless steel.

Within the energy storage housing 12 of the energy storage 8, several identical battery modules (not shown) are arranged, each of which includes several battery cells 14. The battery cells 14 of each battery module are partly electrically connected in series with one another and partly electrically connected in parallel with one another. Some of the battery modules are in turn electrically connected in series with one another and these in turn are electrically connected in parallel with one another. The electrical assembly of the battery modules is electrically contacted with the interface 10, so that when the drive 6 is in operation, the battery modules and thus also the battery cells 14 are discharged or charged (recuperation). Due to the electrical connection, the electrical voltage provided at the interface 10, which is 400 V, is a multiple of the electrical voltage provided with each of the battery modules and also with each of the battery cells 14.

In 2 one of the identical battery cells 14 is shown in a sectional view. The battery cell 14 has a plurality of anodes 16 and cathodes 18, each of which is flat and stacked alternately on top of one another to form a cell stack 20, with a separator 22 being arranged between each adjacent anode 16 and cathode 18. The anodes 16 and the cathodes 18 are arranged perpendicular to a stacking direction 23 of the cell stack 20. In summary, the cell stack 22 has the anodes 18 and cathodes 18 stacked alternately one above the other in the stacking direction 23, between which one of the separators 22 is arranged.

The anodes 16 and the cathodes 18 are each identical in construction and each have a metal foil 24, by means of which the arrester, which is also referred to as a carrier, is formed. An aluminum foil is used as the metal foil 24 for the cathodes 18 and a copper foil is used for the anodes 16. The arrester is coated on both sides with a respective layer that includes an active material. The anodes 16 are arranged one above the other flush with one another in the stacking direction 23, and the cathodes 18 are also arranged one above the other flush with one another in the stacking direction 23. Here, the rectangular anodes 16 protrude at the edge over the rectangular cathodes 18 perpendicular to the stacking direction 23. In other words, the anodes 16 have a larger area than the cathodes 18.

The separators 22 protrude beyond the anodes 16 and are bent at two opposite edges in the stacking direction 23, so that the side or sectional view of the separators 22 is U-shaped. Here, the projection of the separators 22 is selected such that the bent section is up to the adjacent separator 22 is sufficient. In other words, the separators 22 are bent over in such a way that adjacent separators 22 rest against each other. Here, the free ends of the separators 22 lie against the adjacent separator 22 in the area of one of the bends.

The cell stack 20 has a plurality of monocells 25, which are formed by means of one of the anodes 16, one of the cathodes 18 and two of the separators 22, which are each fastened to one another. The monocells 25 are individual units or modules that are used to produce the battery cell 14. The cell stack 20 has an additional anode 16 at one of the ends in the stacking direction 23, onto which one of the monocells 25 is stacked. Otherwise, the cell stack 20 is only formed by means of the monocells 25. Thus, each end of the cell stack 20 is formed in the stacking direction 23 by means of one of the anodes 16.

The cell stack 20 is wrapped around by means of a band 26, which is made of polyethylene or polypropylene. The band 26 is therefore made of an electrically insulating and electrolyte-permeable material. A frictional connection is created between the band 26 and the cell stack 20, and the band 26 is designed in the shape of a band or hollow cylinder. The width of the band 26, i.e. its extent perpendicular to that in 2 The cutting plane shown is equal to the extent of the cell stack 20 in the same direction, which is flush with the band 26. In other words, the cell stack 20 does not protrude beyond the band 26, and the two ends of the cell stack 20 in the stacking direction 23 are each covered over their entire surface by means of the band 26. Two of the sides of the cell stack 20, which are parallel to the stacking direction 23 and opposite one another, are also covered over their entire surface by means of the band 26. In this area, the cell stack 20 with the separators 22, namely their respective bent sections that run parallel to the stacking direction 23, lies flat against the belt 26. Thus, by means of the bent section of the separators 23, electrical contact between the anodes 16 and the cathodes 18 in the band 26, except in the area of the ends in the stacking direction 23, is avoided.

At one of the ends of the cell stack 20 in the stacking direction 23, the band 26 has an overlap 28. By means of the overlap 28, this end of the cell stack is completely covered in the stacking direction 23. In other words, this end is covered with two layers of the tape 26, with a layer of adhesive 30 between the two layers, by means of which the overlap 28 is stabilized. In other words, the ends of the band 26 overlap and are secured together by adhesive 30.

By means of the band 26, the cell stack 20 is stabilized and the monocells 25 are held together and on the additional anode 16. Due to the frictional connection, dissolution of the cell stack 20 is avoided, with no additional components being required. Due to the comparatively wide design of the band 26, there is no local deformation of the cell stack 20, and the performance of the battery cells 14 is therefore increased.

The battery cell 14 also has a housing 32 that is made of aluminum. The housing 32 is designed to be rigid and fluid-tight. In other words, the battery cell 14 is a prismatic cell. The housing 32 is filled with an electrolyte, and connections (not shown) are introduced into the housing 32, which are electrically contacted with some of the anodes 16 and some of the cathodes 18. The connections make it possible to remove or feed electrical energy into the cell stack 20 from outside the housing 32.

In 3 a method 34 for producing battery cells 14 of identical construction is shown. In a first step 36, the band 26 is provided, which is arranged in a plane, as in 4 shown schematically in simplified form. Here, the band 26 is already provided with the adhesive 30 in the area of the later overlap 28. In summary, the band 26 is provided flat.

In a subsequent second step 38, the cell stack 20 is stacked onto the belt 26. For this purpose, the individual anode 16 is first positioned essentially centrally between the two ends of the band 26, with the anode 16 being arranged parallel to the band 26, and with two of the edges of the rectangular anode 16 arranged flush with two of the edges of the band 26 are. The monocells 25, by means of which the rest of the cell stack 20 is formed, are stacked one above the other in the stacking direction 23 on this anode 16.

In a subsequent third step 40, the band 26, as in the 5 shown, bent in such a way that the band 26 rests on the sides of the cell stack 20 that run parallel to the stacking direction 23. Here, the separators 22, which are initially arranged flat, are bent at the edge in the stacking direction 23 by means of the band 26, as in 6 shown.

Following this, as in 6 and 7 shown, one of the ends of the band 26, namely that which is not provided with the adhesive 30, onto the remaining end of the cell stack 20 in the stacking direction 23, this end being covered over the entire surface by means of the band 26. The remaining end of the band 26, which is provided with the layer of adhesive 30, is then folded over to the other end so that the overlap 28 is formed. To connect the two ends of the band 26, a force is exerted on them and consequently also on the cell stack 20 parallel to the stacking direction 23, so that in the area of the overlap the ends of the band 26 rest against one another over the entire surface. The monocells 25 are pressed onto one another and onto the anode 16 and the cell stack 20 is consequently compacted. By adjusting the overlap 28, the band 26 comes into frictional contact with the cell stack 20, which is why it is held by the band 26.

In 8th an alternative embodiment of the battery cell 14 is shown, with the housing 32 being omitted. The cell stack 20 is not modified and still has the anode 16 stacked one above the other in the stacking direction 23 and the monocells 25. Band 26 is also still available. However, the overlap 28 and thus also the layer formed by the adhesive 30 is not located on one of the ends of the cell stack 20 in the stacking direction 23, but on one of the sides running parallel to the stacking direction 23. In this way, an expansion of the battery cell 14 along the stacking direction 23 is reduced.

At the in 9 In the variant of the battery cell 14 shown, the band corresponds to that in 2 The variant shown is arranged, and the cell stack 20 is again not modified. However, the band 26 is completely coated with the adhesive 30 on the side facing the cell stack 20. Thus, the band 26 continues to be provided with the adhesive 30 over its entire surface in the area of the overlap 28, which in turn is located at one of the ends of the cell stack 20 in the stacking direction 23, so that the two ends of the band 26 stick to one another. However, the band 26 is also glued to the cell stack 20, which increases robustness.

At the in 10 Illustrated variant of the battery cell 14 is the adhesive 30 compared to that in 9 The variant shown is applied in strips on the inside of the band 26, so that the material requirement for adhesive 30 is reduced. However, there is still a comparatively stable attachment of the band 26 to the cell stack 20.

The invention is not limited to the exemplary embodiments described above. Rather, other variants of the invention can also be derived from this by the person skilled in the art without departing from the subject matter of the invention. In particular, all of the individual features described in connection with the individual exemplary embodiments can also be combined with one another in other ways without departing from the subject matter of the invention.

Reference symbol list

2

motor vehicle

4

wheel

6

drive

8th

Energy storage

10

interface

12

Energy storage enclosure

14

Battery cell

16

anode

18

cathode

20

Cell stack

22

separator

23

Stacking direction

24

metal foil

25

Monocell

26

tape

28

overlap

30

adhesive

32

Housing

34

Proceedings

36

first step of work

38

second step

40

third step

Claims (8)

Battery cell (14) with a cell stack (20), which has a plurality of anodes (16) and cathodes (18) stacked alternately one above the other in a stacking direction (23), between each of which a separator (22) is arranged, and which is completely non-positively connected on the circumference a band (26) is wrapped around. Battery cell (14). Claim 1 , characterized in that the ends of the cell stack (20) are covered over the entire surface in the stacking direction (23) by means of the band (26). Battery cell (14). Claim 1 or 2 , characterized in that each end of the Cell stack (20) is formed in the stacking direction (23) by means of one of the anodes (16). Battery cell (14) according to one of the Claims 1 until 3 , characterized in that the cell stack (20) has a plurality of monocells (25) stacked one on top of the other, which consists of one of the anodes (16), one of the cathodes (18) and two of the separators (22). Battery cell (14) according to one of the Claims 1 until 4 , characterized in that the band (26) is made of an electrically insulating and electrolyte-permeable material. Battery cell (14) according to one of the Claims 1 until 5 , characterized in that the ends of the band (26) overlap and are attached to each other by means of adhesive (30). Battery cell (14) according to one of the Claims 1 until 6 , characterized in that the separators (22) protrude over the edges of the anodes (16) and cathodes (18) and are bent by means of the band in the stacking direction (23) in such a way that adjacent separators (22) rest against each other. Method (34) for producing a battery cell (14) according to one of Claims 1 until 7 , in which - a band (26) is provided flatly, - on the band (26) a cell stack (20), which has anodes (16) and cathodes (18) stacked alternately one above the other in a stacking direction (23), between which in each case a separator (22) is arranged, is stacked, and - the band (26) is wrapped around the circumference of the cell stack (20) in a force-fitting manner.

Images