Energy cell and method for manufacturing an energy cell

Abstract

The present invention relates to an energy cell (1) comprising an electrode stack (3) and a separator (7) that wraps around the electrode stack (3), wherein a free end (7b) of the separator (7) forms a tab that is connected to a free side surface of the electrode stack (3). The invention further relates to a method for manufacturing an energy cell (1).

Description

[0001] The invention relates to an energy cell and a method for manufacturing such an energy cell.

[0002] Energy cells, such as lithium-ion cells, are essential components in modern energy storage systems and are widely used in various sectors, including the automotive industry. Electric and hybrid vehicles use these cells as their primary energy source to supply their electric powertrains with the necessary energy.

[0003] A typical energy cell consists of several layers of different materials arranged in a specific sequence. These layers include anode layers, cathode layers, and separator layers, which are stacked alternately on top of each other to form a cell stack. The separator prevents direct contact between the electrodes while simultaneously allowing ion flow within the cell. The cell stack is then sealed in a cell casing, which protects the cell from external influences and ensures its structural integrity.

[0004] One aspect of energy cell manufacturing is fixing the individual layers of the cell stack to prevent shifting during housing and subsequent operation. Currently, adhesive strips are used for this purpose, running from a top surface, across a side surface, to a bottom surface. However, the use of adhesive strips can lead to inhomogeneous pressure distribution and thickness variations within the cell stack, which can result in undesirable effects such as lithium plating. Lithium plating is the deposition of metallic lithium on the anode, which can impair the cell's lifespan and safety. Furthermore, the use of adhesive strips requires more material and increases the complexity of the machine design.

[0005] Furthermore, it is known to fix electrodes to a separator using adhesive material and to stack these components alternately. However, this method uses less active material, which can lead to a lower energy density and / or lower energy content.

[0006] The object of the present invention is to provide an energy cell and a method for manufacturing an energy cell that at least partially overcome the aforementioned disadvantages.

[0007] This problem is solved by the energy cell according to claim 1 and the method according to claim 9. Further advantageous embodiments of the invention will become apparent from the dependent claims and the following description of preferred embodiments of the present invention.

[0008] A first aspect of the invention relates to an energy cell comprising an electrode stack and a separator that wraps around the electrode stack. A free end of the separator forms a tab that is connected to a free side face of the electrode stack.

[0009] An energy cell is an electrochemical cell that stores electrical energy and releases it when needed. Generally, an energy cell can be designed as a primary cell (non-rechargeable) or as a secondary cell (rechargeable). For example, rechargeable secondary cells are used in mobile applications such as electric or hybrid vehicles.

[0010] The energy cell comprises an electrode stack consisting of several electrode layers. These electrode layers typically include anode and cathode layers arranged alternately. The electrode stack can be configured in various geometries, such as a planar or rolled arrangement. In one embodiment, the electrode layers and separator layers of one stack direction are stacked on top of each other, forming a planar electrode stack.

[0011] The separator completely encloses the electrode stack, thereby fixing the individual electrode layers. The separator is preferably made of a microporous material that is electrically insulating and simultaneously permeable to an electrolyte. Suitable materials for the separator include, for example, polyolefins such as polyethylene (PE) or polypropylene (PP), which may optionally be provided with a ceramic coating to increase stability and oxidation resistance.

[0012] Wrapping means that the separator is guided around the electrode stack in a circumferential direction and then covers it. In other words, the separator is wrapped around the electrode stack. In the example of a planar arrangement, the electrode stack is essentially cuboid in shape. In this case, the separator can, for example, be wrapped around the long edges of the electrode stack in a circumferential direction so that the side surfaces (cladding surfaces) of the electrode stack are enclosed.

[0013] Between each electrode layer is a separator layer that electrically insulates the individual electrode layers from one another while simultaneously allowing ion flow. The separator layers can be made of the same material as the separator. The separator layers can be formed as a single unit with the surrounding separator. Alternatively, the separator layers can be formed independently of the surrounding separator.

[0014] The free end of the separator forms a tab that connects to the free side surface of the electrode stack. This free end of the separator corresponds to the end that covers the last free side surface of the electrode stack during winding. That is, during winding, the tab is placed on the last free side surface and connected to the electrode stack at this point. Thus, the separator tab is attached to the electrode stack, not to the separator itself. The connection between the tab and the free side surface can be achieved, for example, through a metallurgical bond. The tab serves to securely fix the separator to the electrode stack and prevent the layers from shifting during operation of the energy cell. This contributes significantly to the stability and reliability of the energy cell.

[0015] Wrapping the electrode stack allows the electrode layers to be fixed without the need for additional aids such as adhesive strips. Eliminating adhesive strips ensures a uniform pressure distribution within the electrode stack and prevents variations in its thickness. This reduces the formation of metallic lithium (lithium plating) caused by local thickness changes and increases the lifespan of the energy cell. Furthermore, a clamping force is applied uniformly across the entire electrode width, not just at specific points via adhesive strips. This minimizes deformation and compression of the electrodes and reduces the notch effect of the cathode edges on the anode surfaces, thereby minimizing potential sources of defects. The energy cell according to the invention thus exhibits higher performance and a longer lifespan.

[0016] The manufacturing process is significantly simplified by eliminating the need for adhesive tape. Only one adhesive area is required at the free end of the separator, compared to the multiple adhesive areas required with conventional adhesive tape. This results in more efficient and less error-prone production. Furthermore, the absence of adhesive tape reduces material usage. This leads to lower material costs per energy cell and contributes to cost efficiency. Eliminating adhesive tape also reduces personnel costs for maintenance and replacement of the tape feeders. This results in higher Overall Equipment Effectiveness (OEE) and more efficient production. The reduced material consumption also lowers logistics costs. Therefore, the energy cell according to the invention can be manufactured cost-effectively.

[0017] Although the connection of the tab to the electrode stack also increases the dimension of the electrode stack in the corresponding direction (either in thickness or height if the free side surface is arranged parallel to the electrode algae, or in width if the free side surface is arranged perpendicular to the electrode algae), comparatively little lithium plating occurs, since this increase in dimensions is homogeneous across the free side surface.

[0018] In one embodiment, the separator can completely wrap around the electrode stack in a circular direction. The circular direction refers to the direction in which the separator is guided around the electrode stack.

[0019] Completely wrapping the electrode stack means that the separator fully encloses the stack, ensuring that at least all side surfaces are covered. This typically includes the outer surfaces of the electrode stack. Complete wrapping ensures that the electrode layers are held firmly in place and cannot shift, thus improving the mechanical integrity of the energy cell.

[0020] Completely wrapping the electrode stack with the separator ensures a uniform pressure distribution. This prevents local thickness variations in the electrode stack that could lead to an inhomogeneous pressure distribution. As a result, lithium plating can be at least partially reduced.

[0021] In one embodiment, the side surface can be perpendicular to the electrode layers of the electrode stack. The side surface of the electrode stack is one of the outer faces of the cuboid electrode stack. The side surface is arranged perpendicular to the plane of the electrode layers and extends along the height and length of the electrode stack. The length of the electrode stack extends between the end faces of the electrode stack. When the tab is attached to this side surface, no pressure points are created due to wrinkling and / or blistering, which can be caused by expansion of the energy cell during charging cycles. Thus, mechanical stress due to pressure points at the connection point between the side surface and the separator is prevented. Furthermore, the perpendicular arrangement of the tab to the electrode layers prevents an increase in the thickness of the electrode stack in the stacking direction.This allows for a higher tolerance for an arrangement within a battery housing.

[0022] In one embodiment, the side surface can be arranged parallel to the electrode layers of the electrode stack. The side surface is thus arranged parallel to the electrode layers, or perpendicular to the stacking direction, and extends along the length and width of the electrode stack. This side surface typically has a larger surface area than the side surface that runs perpendicular to the electrode layers. This results in a larger contact area with the separator, thereby improving the connection between the separator and the side surface of the electrode stack.

[0023] In one embodiment, the separator's tab can be bonded to the side surface. A liquid adhesive can be applied to the surface to be bonded on the separator side, for example by jetting, dispensing, spraying, or mechanical pressure. Suitable nozzles and / or valves for these application techniques are known to those skilled in the art.

[0024] Jetting is a technique in which adhesive is applied to the surface to be bonded in the form of small drops or jets, similar to the mechanism of an inkjet printer. This involves contactless dispensing without direct physical contact between a dispensing tool and the surface being coated. This technique allows for very precise and controlled application of the adhesive, as well as flexibility in adjusting the droplet size and application pattern, and avoids mechanical contact during application. Jetting is particularly suitable for spot application of adhesive.

[0025] Dispensing (dispenser technology) refers to the precise metering and application of adhesive in controlled quantities. In adhesive dispensing, the adhesive is applied to specific locations in precisely defined amounts using a special dispensing device or system. Dispensing involves contact dispensing of the adhesive. This means that a dispensing needle or nozzle touches the component.

[0026] When spraying, the adhesive is applied to the surface through a nozzle or valve in the form of a fine mist or spray. This can be achieved using compressed air or other mechanisms. This technique allows for even and / or rapid distribution of the adhesive over a larger area and is therefore suitable for large-scale applications. Spraying also allows for a particularly thin layer of adhesive.

[0027] When applying adhesive mechanically, for example with a roller, the rotating roller applies the adhesive to the surface. The roller can either be dipped directly into the adhesive or the adhesive can be applied to the roller. This technique enables a uniform and continuous application of the adhesive and is suitable for large-area applications and high production speeds. This technique is relatively simple and cost-effective.

[0028] Furthermore, other application mechanisms are conceivable, such as those similar to inkjet printing. Additionally, the adhesive can be applied as a bonding compound to a carrier material, whereby the carrier material is removed after pressing the adhesive onto the surface to be bonded, leaving behind an adhesive surface.

[0029] Nozzles and valves are devices that apply the adhesive to the surface to be bonded in the form of fine drops or jets. These devices enable precise and controlled application of the adhesive. Nozzles and valves can be configured to apply the adhesive in uniform and defined quantities, ensuring consistent distribution and a reliable bond between the separator tab and the free side of the electrode stack. The use of nozzles and valves allows the adhesive to be applied without direct mechanical contact, thus preventing damage to the sensitive materials of the energy cell. Furthermore, nozzles offer a high degree of flexibility in designing the adhesive application, as droplet size and application pattern can be easily adjusted.

[0030] In one embodiment, the separator can wrap around the electrode stack in such a way that a clamping force is exerted on it. This clamping force is generated by tightly wrapping the separator around the electrode stack. That is, during the wrapping process, the separator is subjected to a certain tensile force to induce the necessary clamping force. This clamping force ensures that the electrode layers are held firmly in place and cannot slip.

[0031] In one embodiment, the separator can comprise several separator layers that insulate the electrode layers of the electrode stack from one another, with at least one electrode layer being bonded to a separator layer. As already indicated above, in this embodiment the separator and the multiple separator layers are formed as a single piece. The separator is therefore ribbon-shaped. For example, the separator can form the multiple separator layers by means of a Z-fold known to those skilled in the art. The Z-fold enables an efficient and compact arrangement of the separator layers between the electrode layers, which improves mechanical stability and electrical insulation. Furthermore, the Z-fold can also improve the positional accuracy of the electrode layers.

[0032] Furthermore, bonding can create a strong and stable connection between the electrode layers and the separator layers. The adhesive can be applied to either a separator layer or an electrode layer to ensure a uniform and controlled bond.

[0033] In one embodiment, the energy cell can be designed as a prismatic cell or as a pouch cell. A prismatic cell is a type of energy cell characterized by its rectangular, cuboid geometry. A pouch cell is a type of energy cell characterized by its flexible, pouch-like packaging.

[0034] A second aspect of the present invention relates to a method for manufacturing an energy cell. The method comprises the following steps: - Providing a stack of electrodes; - Wrapping the electrode stack with a separator so that one side of the electrode stack remains free; and - Connecting a tab of the separator to the free side surface to completely wrap the electrode stack.

[0035] The "provision" can include the fact that the finished electrode stack is already available or that it is only just being assembled.

[0036] During the wrapping process, one side surface is left free. This free side surface is then connected to the separator's tab to completely wrap the electrode stack. This ensures the separator is attached to the electrode stack and not to itself.

[0037] In one embodiment, the method may further include applying an adhesive to the tab of the separator for bonding to the free side surface by (the techniques described above) spraying, jetting, dispensing or mechanical pressing.

[0038] In one embodiment, the method may further include folding the tab onto the free side surface along an edge of the electrode stack by using compressed air, vacuum, a fixed stop, a brush, gravity or tensile force.

[0039] In one embodiment, the separator can be subjected to a tensile force during the wrapping of the electrode stack. As described above, the applied tensile force induces a clamping force on the electrode stack through the wrapping separator, thus fixing the electrode layers in place.

[0040] In one embodiment, the provision of the electrode stack can further comprise alternating stacking of several electrode layers and several separator layers, wherein at least one electrode layer is bonded to a separator layer. As already explained above, such an adhesive can be applied to a separator layer or an electrode layer to ensure a uniform and controlled bond.

[0041] In one embodiment, bonding can occur at regular layer intervals. This means that only every nth layer interface between the electrode layer and the separator layer is bonded. This reduces the manufacturing process effort.

[0042] In one embodiment, the free side surface can run perpendicular to the electrode layers of the electrode stack. As mentioned above, this side surface is particularly suitable for joining with the tab due to the absence of wrinkles and / or bubbles.

[0043] Exemplary embodiments of the invention will now be described by way of example and with reference to the accompanying drawing. This shows: Fig. 1. Schematic representation of an energy cell in a perspective view; Fig. 2a, b schematically an energy cell in a sectional view according to a first embodiment; Fig. 3 schematically a sectional view of the energy cell according to the first embodiment with connection points for the individual layers; Fig. 4a, b schematically the creation of a connection point between the energy cell and a separator; Fig. 5 schematically an energy cell in a sectional view according to a second embodiment; Fig. 6. A schematically represented method for manufacturing an energy cell, shown as a block diagram

[0044] Fig. Figure 1 schematically shows an energy cell 1 comprising an electrode stack 3 with a plurality of electrode layers 5. Six electrode layers 5 are shown as an example, comprising cathode and anode layers stacked alternately. Fig. 1 are separator 7 or separator layers 7a not shown.

[0045] Fig. Figure 2a schematically shows a sectional view of the energy cell 1 according to a first embodiment in a plane perpendicular to the longitudinal direction of the energy cell 1. A separator layer 7a is arranged between each of the individual electrode layers 5 for electrical insulation of the electrode layers 5. The separator layers 7a are part of the separator 7 and are formed by a Z-fold of the separator 7. The separator 7 is designed with an excess length so that, after the Z-fold, the separator 7 can be folded around the energy cell 1 and thus completely wraps the energy cell 1 circumferentially.

[0046] To attach the separator 7 to the energy cell 1, an adhesive surface 9 is provided at its free end 7b (tab). The adhesive surface 9 is dimensioned such that its area corresponds to the (free) side surface to which the free end 7b is connected. Thus, the free end 7b is attached to the (in Fig. The separator 7 is glued to the side surface of energy cell 1 (shown on the left), thus attaching it to the energy cell 1. The free side surface is arranged perpendicular to the electrode layers 5. The Fig. The mounting surface shown (side surface) is particularly suitable because there is little or no horizontal expansion of the energy cell 1 during a charging cycle due to wrinkling and / or blistering.

[0047] Fig. Figure 2b shows a modification of energy cell 1. Fig. 2a, the difference being in the design of the adhesive surface 9. In Fig. Figure 2b shows a reduced adhesive area 9a, which is arranged at one end section of the free end 7b. In the assembled state, the reduced adhesive area 9a extends longitudinally (perpendicular to the plane of the image) over the entire length of the separator 7 or the electrode stack 3 of the energy cell 1, and in the stacking direction only partially over the free side surface of the electrode stack 3. This reduces the amount of adhesive and thus the foreign particles in the energy cell 1.

[0048] Fig. Figure 3 corresponds to the schematic sectional view of the Fig. 2, whereby for the sake of clarity most of the reference marks have been omitted. Fig. Figure 3 represents connection points 11 between the individual electrode layers 5 and separator layers 7a. It can be seen that the first connection points 11a are located within a first interface 3a between two layers 5 and 7a at predetermined (possibly equidistant) intervals d1. In a second interface 3b between two layers 5 and 7a, second connection points 11b are also located at predetermined (possibly equidistant) intervals d2. The first and second connection points 11a and 11b are arranged alternately and offset from each other in the stacking direction. This prevents a concentration of connection points 11a and 11b in the stacking direction, thus reducing thickness variations in the energy cell 1 and consequently the risk of lithium plating.

[0049] In Fig. In section 3, every second layer interface is provided with connection points 11a, 11b. However, different layer interface spacings can also be selected, such as every interface, every third interface, every fourth interface, etc. Furthermore, the predetermined distances d1 and d2 between the connection points 11a, 11b can be the same or different.

[0050] Fig. Figure 4a shows a step in the production of energy cell 1. Fig. 2.

[0051] To fold over the free end 7b of the separator 7, a targeted supply of compressed air can be used. This can be achieved, for example, by a compressed air nozzle positioned along the edge of the electrode stack 3. The compressed air nozzle generates an airflow that moves the free end 7b of the separator 7 towards the free side surface of the electrode stack 3. By applying the compressed air in a controlled manner, the free end 7b can be folded over precisely and evenly so that it lies flat against the free side surface. Alternatively, a vacuum tool can be used for folding. This tool consists of a vacuum nozzle or a vacuum plate. The vacuum nozzle creates a negative pressure that attracts the free end 7b of the separator 7 and moves it towards the free side surface of the electrode stack 3.By using compressed air or vacuum to fold over the free end 7b of the separator 7, a mechanical stress on the electrode layers 5, which could occur with other folding methods, is avoided.

[0052] Furthermore, a rigid stop or a brush with flexible bristles can also be used. For example, a rigid stop can be positioned along the edge of the electrode stack 3 and then folded up to press the free end 7b against the free side surface of the electrode stack 3. By using the rigid stop in a controlled manner, the free end 7b is folded over precisely and evenly so that it lies flat against the free side surface. The use of the stop provides high repeatability of the folding process. When using the brush, the free end 7b of the separator 7 is folded around a longitudinal edge (in Fig. 4a bottom left) and then pressed against the free side surface with the brush. The brush can adapt to the contours of the electrode stack, thus enabling even pressure of the free end 7b against the free side surface.

[0053] In another example, a tensile force can also be applied to the free end 7b of the separator 7. For this purpose, a pulling device can be used that grips the free end 7b and pulls it with a controlled tensile force towards the free side surface of the electrode stack 3. By applying the tensile force uniformly, the free end 7b is folded over smoothly and without creases. This reduces the risk of wrinkling, which could lead to uneven pressure distributions and potential defects such as lithium plating.

[0054] As in Fig. As shown in Figure 4b, gravity can also be used to fold over the free end 7b. To fold over the free end 7b of the separator 7, the electrode stack 3 is positioned so that gravity pulls the free end 7b towards the free side surface of the electrode stack 3. This can be achieved by tilting or positioning the electrode stack 3 so that the free end 7b falls downwards due to gravity and rests against the free side surface of the electrode stack 3. Using gravity does not require complex mechanical devices or additional energy sources. Furthermore, gravity exerts a uniform and gentle force on the free end 7b of the separator 7. This minimizes the risk of mechanical damage to the electrode stack 3 and the separator 7.

[0055] Fig. Figure 5 schematically shows a sectional view of the energy cell 1 according to a second embodiment in a plane perpendicular to the longitudinal direction of the energy cell 1. The structure essentially corresponds to the structure of the energy cell 1 from Fig. 2a with the difference that the free side surface of the electrode stack 3 is located at the bottom, i.e., parallel to the electrode layers 5. Accordingly, the free end 7b of the separator 7 is connected to the electrode stack 3 in this bottom-facing side surface. The free side surface is not covered by a separator layer 7a. In the second embodiment, the connecting surface between the free end 7b and the electrode stack 3, or the adhesive surface 9, is, in comparison to Fig. 2 larger, so that a more stable attachment of the separator 7 to the electrode stack 3 is possible. Furthermore, the arrangement can be arranged according to Fig. 5 also according to the principle from Fig. 2b is modified, i.e., the adhesive area 9 is reduced so that it only partially extends over the free side surface of the electrode stack 3.

[0056] Fig. Figure 6 shows a process for manufacturing the energy cell 1, represented as a block diagram.

[0057] In block S1, an electrode stack 3 is provided. This electrode stack 3 consists of several electrode layers 5, which are arranged alternately as anode and cathode layers. Between the electrode layers 5 are the separator layers 7a of the separator 7, which are formed by a Z-fold of the separator 7 between the electrode layers 5.

[0058] The provisioning according to block S1 can optionally include block S0. In block S0, the electrode layers 5 and separator layers 7a are stacked alternately to form the electrode stack 3. During stacking, at least one electrode layer 5 is bonded to a separator layer 7a to ensure a firm and stable bond between the two layers. An adhesive can be applied selectively to the separator layer 7a or the electrode layer 5. Bonding can occur at regular layer intervals, for example, only every nth layer interface between the electrode layers 5 and the separator layers 7a, to reduce the manufacturing process effort. Bonding improves the positional accuracy of layers 5 and 7a of the electrode stack 3 and prevents slippage of layers 5 and 7a during operation of the energy cell 1. Further details regarding Fig. 3 apply accordingly to block S0.

[0059] In block S2, the electrode stack 3 is wrapped with the separator 7, which has an extra length. The separator 7 is guided around the electrode stack 3 in the circumferential direction, so that initially one side surface of the electrode stack 3 remains free.

[0060] In block S3, an adhesive is applied to the free end 7b (tab) of the separator 7. The adhesive can be applied by various methods, such as spraying, jetting, dispensing, or mechanical pressure. These methods ensure that the adhesive is applied evenly to the tab to guarantee a permanent bond with the free side face of the electrode stack 3.

[0061] In block S4 step, the free end 7b of the separator 7 is folded onto the free side surface of the electrode stack 3. Various methods can be used for this, as described above, such as compressed air, vacuum, a fixed stop, a brush with flexible bristles, gravity, or tensile force.

[0062] In block S5, the folded-over tab of the separator 7 is connected to the free side surface of the electrode stack 3. This ensures that the separator 7 is firmly attached to the electrode stack 3 and cannot slip. Reference symbol list 1 energy cell 3 electrode stacks 3a first layer interface 3b second layer interface 5 Electrode position 7 Separator 7a Separator location 7b free separator end 9 adhesive surfaces 9a reduced adhesive area 11a first connection points 11b second connection points d1, d2 distances S0 Stacking the layers S1 Providing an electrode stack S2 Wrapping the electrode stack with the separator S3 Applying an adhesive to the free end of the separator S4 Folding the free end S5 Connecting the free end

Claims

[1] Energy cell (1), comprising: an electrode stack (3); and a separator (7) that wraps around the electrode stack (3), wherein a free end (7b) of the separator (7) forms a tab that is connected to a free side surface of the electrode stack (3). [2] Energy cell (1) according to claim 1, wherein the separator (7) completely wraps the electrode stack (3) in a circular direction. [3] Energy cell (1) according to claim 1 or 2, wherein the side surface is perpendicular to the electrode layers (5) of the electrode stack (3). [4] Energy cell (1) according to claim 1 or 2, wherein the side surface is arranged parallel to the electrode layers (5) of the electrode stack (3). [5] Energy cell (1) according to one of the preceding claims, wherein the tab (7b) is bonded to the side surface. [6] Energy cell (1) according to one of the preceding claims, wherein the separator (7) wraps the electrode stack (3) such that a clamping force is exerted on the electrode stack (3). [7] Energy cell (1) according to one of the preceding claims, wherein the separator (7) comprises several separator layers (7a) that isolate the electrode layers (5) of the electrode stack (3) from each other, and at least one electrode layer (5) is bonded to a separator layer (7a). [8] Energy cell (1) according to any of the preceding claims, wherein the energy cell (1) is designed as a prismatic cell or as a pouch cell. [9] Method for manufacturing an energy cell (1), comprising: (S1) Provide an electrode stack (3); (S2) Wrapping the electrode stack (3) with a separator (7) so that one side face of the electrode stack (3) remains free; and (S5) Connecting a tab (7b) of the separator (7) to the free side surface to completely wrap the electrode stack (3). [10] The method of claim 9, further comprising: (S3) Applying an adhesive to the tab (7b) of the separator (7) for bonding to the free side surface by spraying, jetting, dispensing or mechanical pressing. [11] Method according to claim 9 or 10, further comprising: (S4) Fold over the tab (7b) onto the free side surface along an edge of the electrode stack (3) by using compressed air, vacuum, a firm stop, a brush, gravity or pulling force. [12] Method according to one of claims 9 to 11, wherein the separator (7) is subjected to a tensile force during the wrapping of the electrode stack (3). [13] Method according to any one of claims 9 to 12, comprising providing the electrode stack (3): (S0) alternating stacking of several electrode layers (5) and several separator layers (7a), wherein at least one electrode layer (5) is bonded to a separator layer (7a). [14] Method according to claim 13, wherein the bonding is carried out at regular layer intervals. [15] Method according to any one of claims 9 to 14, wherein the free side surface is perpendicular to the electrode layers (5) of the electrode stack (3).

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