Method and apparatus for laminating battery cell components

Abstract

The present invention relates to a method for laminating components of a battery cell (1), the components having at least electrodes (2) of a first electrode type (3) and a separator layer (4) arranged in an overlapping manner along a stacking direction (5) to form a stack (6). Additionally, an apparatus for laminating the components of a battery cell (1) is also presented.

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for laminating battery cell components.

[0002] The battery cell includes at least one electrode of a first electrode type and at least one electrode of a second electrode type, each separated by a separator material and arranged in a stacked arrangement such that the electrodes overlap each other along the stacking direction. The electrodes and separators, also referred to herein as components, form a stack of overlapping layers. Each electrode has a support material coated with an active material and a conductor for electrical contact connection of the electrode. The battery cell is particularly a secondary battery cell.

[0003] Batteries, especially lithium-ion batteries, are increasingly being used to power automobiles. Batteries typically consist of battery cells, each of which has a stack of layers—anode, cathode (electrode)—with a separator material disposed between them. Conductors at each electrode are used to conduct electrical current from the battery cell to an electrical load located outside the battery cell.

[0004] A battery cell typically includes a casing in which one or more stacks are arranged. Electrode conductors of the same electrode type are connected in parallel to each other within the casing and to terminals on the surface of the casing. In solid-state battery cells, a solid or non-liquid electrolyte is used. In other battery cells, a liquid electrolyte is filled into the volume enclosed by the casing. Both types of battery cells can be manufactured using the proposed method.

[0005] Lamination involves, inter alia, heating the separator layer or material so that it forms an adhesive bond with the active material of the adjacently disposed electrode.

[0006] The lamination of the entire battery cell stack is a time-critical process in the production of lithium-ion battery cells. For the lamination of the stack, it is known to use so-called hot presses or heat presses. In this type of machine, pressure and heat are applied to the stack by two heatable plates. Heating of the stack here is carried out by conduction. In addition to lamination, the stack can also be fixed externally by tape.

[0007] Previously known methods require processing times of 45 to 60 seconds per stack. Acceleration of the process is not possible. The long processing times are due to the heat transfer from each plate.

[0008] However, laminated stacks offer advantages over taped-only stacks in handling the battery cells and in further processing into complete battery cells: battery cells with laminated stacks have better qualitative properties, especially with respect to lifespan.

[0009] In battery cells, gas generation through a number of mechanisms can negatively impact cell output and performance. During lamination, the negative effects of gas generation can be reduced by forcing the gas to migrate to the edges of the laminate, where bubbles form between the individual layers of the laminate, thereby increasing the interfacial resistance between the layers. Additionally, laminated interfaces often have lower impedance (resistance) than unlaminated interfaces.

[0010] The adhesive bonding of the individual layers to one another ensures that the electrode alignment (e.g., the coplanar alignment of the active materials along the stacking direction) remains maintained during handling of the stack.

[0011] Korean Patent Publication No. 1020160047690 discloses an apparatus and method for laminating battery cells using induction, where mono- or bi-cells are guided through the apparatus as a continuous material, so that lamination is performed on the cell components as they are moved through the apparatus.

[0012] JP 2004-207178 A discloses an apparatus and method for manufacturing a fuel cell or battery cell, in which electrodes are joined to a casing using an inductively heated adhesive.

[0013] EP 3147983 A1 discloses a method and an apparatus for manufacturing a fuel cell, in which electrodes and separators are arranged one above the other to form a stack and bonded to each other with an adhesive, and the stack is heated by induction.

[0014] The present invention aims to at least partially solve the problems mentioned in relation to the prior art. In particular, a method and an apparatus are proposed that allow for lamination of components of a battery cell, where the battery cell can be manufactured as inexpensively as possible and the layers of the stack of components are arranged as precisely as possible on top of each other and maintained during handling of the stack.

[0015] To achieve the above object, a method having the features of claim 1 and a device having the features of claim 10 are provided. Advantageous developments are the subject of the respective dependent claims. The features individually recited in the claims can be combined with one another in a technically significant manner and can be further supplemented by specific facts described and / or details in the drawings, which show further variants of the invention.

[0016] A method for laminating components of a battery cell is proposed, wherein the components have at least electrodes of a first electrode type and a separator layer arranged in a stacking direction to form a stack. The method comprises at least the following steps: a) providing an induction lamination apparatus including at least a first plate and a second plate and an induction device; b) placing a stack of components between a first plate and a second plate; c) pressing the laminate with a plate along the lamination direction; d) activating the induction device to heat the at least one separator layer to form an adhesive bond between the separator layer and the electrode; e) moving the plates away from each other; f) removing the laminated component from the apparatus; Includes:

[0017] The above (non-exclusive) division of method steps a) to f) is primarily used for the sake of distinction only, and no order and / or dependency is to be imposed. The frequency of the method steps can be varied. Likewise, the method steps can be at least partially overlapped in time with one another or performed simultaneously. Very particularly preferably, steps a) to c) are performed in sequence, followed by steps e) and f). Steps c) and d) can be performed in sequence or interchanged, or can be performed at least temporarily simultaneously. In particular, steps a) and b) and steps e) and f) are performed in the order shown, with steps c) and d) being performed in any order or at least partially together between steps b) and e). Optionally, at least step d) can be performed at least partially during step e).

[0018] The device provided in step a) particularly includes a first plate and a second plate, by means of which the stack can be pressed. The plates are particularly configured so that the mutual contact surfaces of the stack and the plates (hereinafter also referred to as contact surfaces) are respectively arranged parallel to each other or extend parallel to each other. In particular, the corresponding surfaces of the plates extend at least over, and possibly even beyond, the contact surface of the stack, i.e., in particular are configured with a larger area. In particular, the stack can be pressed together via the plates, in particular with as uniform a force distribution as possible, at least in planes extending parallel to the respective contact surfaces.

[0019] At least one plate can have nanoscale or macroscale structures on the surface of the contacting face, which can prevent adhesion between the plate and the stack. Alternatively or additionally, the plate can have a plurality of holes through which compressed air or a mechanical ejector can be supplied to separate the plate and the stack.

[0020] In particular, a plurality of stacks in step b) can be placed between plates and further processed.

[0021] The induction device in particular has one or more induction coils by means of which at least a portion of the stack can be directly heated. During operation of the induction device, eddy currents are generated in the conductive components, which directly heat the stack. Induction heating is more efficient than other heating methods, since energy is induced directly into the components provided for heating, i.e., heat is generated directly in each component and does not have to be transferred from the outside to the interior of the stack and / or components by heat conduction, heat radiation or convection, as in other heating methods.

[0022] Induction heating is particularly advantageous when laminating these components, because even if the stack is large and has many components, it is possible to heat all the components (or components provided for heating), as well as components spaced apart from each inductor.

[0023] In step b), the stack is placed between the plates. In this case, the stack can already be prepared outside the device and then placed in the device as a stack. Alternatively, the stack can be formed by the components first in the device.

[0024] In step c), the laminate is pressed by a plate. Here, the components of the laminate are pressed against each other, particularly at a pressure of more than 1 bar, preferably more than 2 bar. In particular, the pressing here is carried out at a pressure of up to 20 bar, particularly up to 10 bar. By pressing, air is particularly expelled from the laminate, so that the components of the laminate form a contact surface with each other as large as possible. In particular, during pressing, force-displacement control, which is basically known, is used to control the pressure during pressing in a desired manner.

[0025] Step d) involves activating the induction device and heating at least one separator layer, in particular to form an adhesive bond between the separator layer and the electrode. In this case, the separator layer is not heated directly. In particular, other components of the stack (i.e., components other than the separator layer) are heated by induction. The separator layer is then heated by heat conduction, in particular from the component heated by induction. Alternatively or additionally, the separator layer may be heated.

[0026] In step e), the plates are separated from each other, i.e., the pressing of the laminate is terminated. In particular, this separation only takes place after at least one of the components has cooled to a temperature below its melting temperature (or glass transition temperature), which in particular prevents the formation of bubbles.

[0027] In step f), the laminated components and / or laminated stack are removed from the device, in particular with all components of the stack now bonded to one another at least via the adhesive joints formed by the method.

[0028] In particular, the stack has a plurality of electrodes (e.g., anodes or cathodes) of a first electrode type, a plurality of electrodes (e.g., cathodes or anodes) of a second electrode type (different from the first electrode type), and one separator layer disposed between the electrodes.

[0029] In particular, the stack comprises at least 10 electrodes of one electrode type, preferably at least 100 electrodes of one electrode type, particularly preferably at least 200 electrodes of one electrode type.

[0030] A large number of components cannot be produced, especially in a continuous manner. The method proposed here, in which the already individualized electrode layers are arranged to form a stack and the stack containing the components is already cut to be placed in a battery cell after lamination and finished, does make it possible to laminate a large number of components stacked on top of each other.

[0031] Separator layers and electrodes may be stacked together to form a stack, but in this case the different separator layers are not bonded to each other.

[0032] In particular, at least some of the separator layers are bonded to one another. For example, each two separator layers form a pocket for an electrode, whereby the electrode is arranged in a closed pocket. Alternatively, the separator layer as a whole may be Z-folded and extend over multiple electrodes. In particular, the separator layer as a whole may be Z-folded and extend over all electrodes of the stack.

[0033] In particular, all of the separator layers are bonded together, with the stack having only one separator material formed as a single unit.

[0034] In particular, at least one separator layer or exactly one separator layer is arranged between the stack and the first plate and between the stack and the second plate in steps b) to e) by extending to surround the stack, so that the stack as a whole is enclosed by the separator layer and the components can be fixed in their relative positions to one another.

[0035] In particular, at least one electrode has a support material and a coating containing an active material on at least one side of the support material, the coating being arranged between the support material and the separator in the stack, and the induction device is driven in particular so that the support material is heated by induction, which in turn heats at least one separator layer by thermal conduction.

[0036] In particular, the separator material may be composed of inductively heatable particles or may include a coating having inductively heatable particles.

[0037] In particular, the individual electrodes comprise a sheet-like support material, for example made of copper or aluminum material, which is coated on one side, or in particular on both sides, with active material, and the active materials of the different electrode types are arranged separated from one another, in particular by a separator material.

[0038] In particular, each conductor is formed by an uncoated area of ​​the support material.

[0039] In particular, the induction device can be driven such that parameters that are particularly suitable for each type of support material are selected, so that efficient heating of the support material can be achieved.

[0040] In particular, at least one plate, or possibly each plate, is configured as an inductor or comprises at least one inductor.

[0041] In particular, at least one of the plates has a plurality of inductors.

[0042] Alternatively, the at least one inductor may be spaced apart from the plates or may be disposed only separately from the plates.

[0043] In particular, it is proposed to arrange a stack consisting of individual electrodes and separator layers between two plates. In particular, an inductor is integrated into the plates. The plates allow a defined force to be applied to the stack. The inductor allows, in particular, material-specific heating of the electrodes from the inside, since material-dependent frequency control is possible. The required temperature for the laminate can thus be achieved within a few seconds throughout the stack.

[0044] In particular, lamination of the stack can be achieved in less than 20 seconds, particularly less than 15 seconds, or even less than 10 seconds. In particular, this time is independent of the number of layers in the stack. Thus, in particular, stacks having at least 100 electrodes of one electrode type, particularly preferably at least 200 electrodes of one electrode type, can also be laminated (completed) within the stated maximum time of 20 seconds.

[0045] This method achieves a more uniform heating of the stack or component (especially when considering short heating durations) compared to heating by convection or conduction, in particular by deliberately heating the support materials distributed in the stack and then heating the separator materials, respectively, via these support materials.

[0046] This means that the heating of the electrodes and thus the separator also results in a porous structure of the separator material: the entire separator material is not heated, but in particular only the contact surface of the separator material towards the adjacently arranged electrode.

[0047] Furthermore, an apparatus for laminating battery cell components is proposed, which is configured, designed or equipped to perform at least steps b) to e) of the method described above, and which comprises at least a first plate, a second plate and an induction device.

[0048] In particular, the device comprises a control device designed or equipped or configured or programmed to carry out the method described above or at least steps b) to e).

[0049] The control device controls at least It is possible to drive or control the laminating device, i.e. Driving an induction device, or Bringing plates closer together and / or further apart (to press the stack), especially by displacement control and force control can be done, or Controlling the handling of laminates or individual components can be done.

[0050] Furthermore, a battery cell is proposed, wherein the battery cell in particular comprises a casing enclosing a volume and comprises at least one laminate and an electrolyte arranged within this volume.

[0051] The battery cells are in particular pouch cells (including a deformable casing made of a pouch film) or prismatic cells (including a shape-fixed casing). The pouch film is a known deformable casing material used as a casing for so-called pouch cells. The pouch film here is a composite material containing, for example, plastic and aluminum.

[0052] The battery cells are in particular lithium-ion battery cells.

[0053] The individual electrodes are arranged one on top of the other to form a stack, and each electrode is associated with a different electrode type, i.e., configured as an anode or a cathode, with the anodes and cathodes arranged alternately and separated from each other by a separator material.

[0054] The battery cell is a storage unit used to store electrical energy in, for example, a vehicle. In particular, the vehicle has an electric machine (traction drive) that can be driven by the electrical energy stored in the battery cell.

[0055] Furthermore, a motor vehicle is proposed which includes at least a traction drive and a battery with at least one of the described battery cells, the traction drive being able to be supplied with energy from the at least one battery cell.

[0056] The method can be carried out by a computer or in cooperation with a processor of a computer or control unit.

[0057] Therefore, a data processing system including a processor adapted or configured to perform the method or some of the steps of the proposed method is also proposed.

[0058] A computer-readable storage medium may also be provided that contains instructions that, when executed by a computer or processor, cause the computer or processor to perform at least a portion of the steps of the present or proposed method.

[0059] Description of the battery cell method specifically applies to the laminating apparatus, battery cell, vehicle, control device, and computer-implemented method (i.e., computer or processor, data processing system, computer-readable storage medium), and vice versa.

[0060] The use of the indefinite articles "ein", "eine", "einer" and "eines", especially in the claims and the specification reflecting them, does not itself denote a numeral. Thus, concepts or elements correspondingly introduced by such indefinite articles mean that there is at least one of these concepts or elements, and in particular that there may be a plurality of these concepts or elements.

[0061] As a reminder, the use of numerals ("first," "second," ...) in this specification is primarily (and only) used to distinguish between multiple similar objects, quantities, or processes; that is, they do not specifically impose a dependency and / or sequence between those objects, quantities, or processes. Where a dependency and / or sequence is required, this will be explicitly stated in the specification or will become apparent to those skilled in the art upon consideration of the specifically described configuration. Where elements may occur multiple times ("at least one"), a description of one of those elements applies equally to all or more of those elements, but this is not required.

[0062] The present invention and its technical environment will be described in detail below with reference to the accompanying drawings. Please note that the present invention is not limited to the described embodiments. In particular, unless otherwise expressly stated, partial aspects of the facts shown in the drawings can be extracted and combined with other components and findings based on this specification. In particular, please also note that the drawings, especially the scales shown, are merely approximate. [Brief explanation of the drawings]

[0063] [Figure 1] FIG. 1 is a side view showing an apparatus for laminating a laminate. [Figure 2] 2 is a side view showing a portion of an apparatus having the stack shown in FIG. 1. FIG. [Figure 3] FIG. 1 is a side view showing a stack formed from n-type mono cells. [Figure 4] FIG. 1 is a side view of a stack including an integral separator material. [Figure 5] FIG. 1 is a side view showing a support material, e.g., an anode, coated on one side with an active material. [Figure 6] FIG. 1 is a side view showing a support material, e.g., a cathode, coated on both sides with active material. [Figure 7] FIG. 1 is a side view of a monocell including a one-sided coated anode and a one-sided coated cathode, with the cathode disposed within a pocket of separator material. [Figure 8] FIG. 1 is a side view showing a stack including separator material folded in a Z-shape. [Figure 9] FIG. 1 is a side view of a stack having stacked monocells, each with an anode disposed within one separator material pocket. [Figure 10] 1A and 1B are side and top views showing a plate formed as an inductor. [Figure 11] 1A and 1B are side and top views showing a plate with multiple inductors.

[0064] Fig. 1 shows a side view of an apparatus 7 for laminating a stack 6. Fig. 2 shows a side view of a portion of the apparatus 7 having the stack 6 shown in Fig. 1. Fig. 3 shows a side view of a stack 6 formed from n-type mono cells. Figs. 1 to 3 will be explained together below.

[0065] The device 7 is suitably configured, designed or equipped to carry out at least steps b) to e) of the above-described method and comprises a first plate 8, a second plate 9 and a guide device 10. The device 7 further comprises a control device 17. The control device 17 can drive or control the laminating device 7, i.e., for example, the guide device 10, and in particular can drive and control the plates 8, 9 to approach each other (press the laminate 6) and / or move away from each other by displacement control and force control. In this case, force measurement by the control device can be performed to ensure damage-free pressing of the laminate.

[0066] In step a) of the method, an induction lamination apparatus 7 is provided, including a first plate 8, a second plate 9, and an induction device 10. In step b), a stack 6 of components is placed between the first plate 8 and the second plate 9. The components include electrodes 2 of a first electrode type 3 and a second electrode type 11, and separator layers 4, arranged one above the other along the stacking direction 5 to form the stack 6. In step c), the plates 8 and 9 press the stack 6 together along the stacking direction 5 with force 18 (see FIGS. 1 and 2). In step d), the induction device 10 is activated and the separator layers 4 are heated to form adhesive bonds between the respective adjacent electrodes 2. FIG. 2 shows heat conduction within the stack 6, starting from the support material 13 of each electrode 2. In step e) the plates 8, 9 are pulled apart and in step f) the laminated component is removed from the device 7.

[0067] The plates 8, 9 of the device 7 are configured so that the surfaces where the stack 6 and the plates 8, 9 come into contact with each other (hereinafter also referred to as contact surfaces) are arranged or extend parallel to each other. The corresponding surfaces of the plates 8, 9 extend beyond the surfaces of the stack 6 that come into contact with these plates 8, 9, i.e., are formed with a larger area. The stack 6 can be pressed together via the plates 8, 9, and it is desirable to achieve as uniform a force distribution as possible here, at least in the planes that extend parallel to the contact surfaces.

[0068] The induction device 10 has one or more inductors 16 or induction coils, which can directly heat at least a portion of the laminate 6 .

[0069] Step d) involves activating the induction device 10 and heating the separator layer 4 to form an adhesive bond between the separator layer 4 and the electrode 2. In this case, the separator layer 4 is not heated directly. Another component of the stack 6, namely the support material 13 of the electrode 2 (i.e., a material other than the separator layer 4), is heated by induction. The separator layer 4 is then heated by heat conduction originating from the inductively heated component.

[0070] The laminate 6 has a plurality of electrodes 2 (e.g., anodes or cathodes) of a first electrode type 3, a plurality of electrodes 2 (e.g., cathodes or anodes) of a second electrode type 11 (different from the first electrode type 3), and one separator layer 4 disposed between each of the electrodes 2.

[0071] Each electrode 2 has a sheet-like support material 13, for example made of copper or aluminum, coated on both sides with active material. The active materials of the different electrode types 3, 11 are separated from one another by separator material 12. Each conductor 19 of the electrode 2 is formed by an uncoated area of ​​the support material 13.

[0072] 4 shows a side view of a laminate 6 having an integral separator material 12. See also the description of FIGS.

[0073] The integral separator layer 4 follows a Z-fold and extends over all of the electrodes 2 of the stack 6. In this case, all of the separator layers 4 are bonded to one another, and the stack 6 has only one integrally formed separator material 12.

[0074] Exactly one separator layer 4 extends to surround the stack 6, which was arranged in steps b) to e) between the stack 6 and the first plate 8 and between the stack 6 and the second plate 9. The stack 6 is therefore entirely enclosed by the separator layer 4, which allows the components to be fixed in position relative to one another.

[0075] 5 shows a side view of a support material 13, e.g., an anode, coated on one side with an active material. The electrode 2 has a support material 13 and a coating 15 on one side 14 of the support material 13 that includes an active material.

[0076] 6 shows in side view a support material 13, e.g., a cathode, coated on both sides with active material (see also the description of FIG. 5).

[0077] 7 shows a monocell comprising an anode coated on one side and a cathode coated on the other side, the cathode disposed within a separator material 12 configured as a pocket. Each electrode 2 has a support material 13 and, on one side 14 of the support material 13, a coating 15 containing the active material.

[0078] Figure 8 shows a side view of a stack 6 with Z-folded separator material 12. See also the description of Figure 4. Each electrode 2 has a support material 13 and, on both sides 14 of the support material 13, a coating 15 containing an active material.

[0079] 9 shows a side view of a stack 6 having stacked monocells, each with an anode disposed in a pocket of separator material 12. Each electrode 2 has a support material 13 and, on both sides 14 of the support material 13, a coating 15 containing an active material.

[0080] 10 shows a side view and a plan view of a plate 8 configured as an inductor 16. See also the description of FIGS.

[0081] 11 shows a side view and a plan view of a plate 8 with a number of inductors 16. The individual inductors 16 can be individually driven, for example, via a control device 17, which allows for position-dependent control of the inductive heat supply. [Explanation of symbols]

[0082] 1 battery cell 2 electrodes 3. First electrode type 4 Separator layer 5 Lamination direction 6 Laminate 7. (Laminating) equipment 8. First Plate 9 Second Plate 10 Guidance device 11 Second electrode type 12 Separator material 13 Support material 14 sides 15 Coating 16 Inductors 17 Control device 18 power 19 Conductor 20 Casing

Claims

1. A method for laminating components of a battery cell (1), comprising the steps of: The component comprises at least electrodes (2) of a first electrode type (3) and separator layers (4) arranged in a stacking direction (5) to form a stack (6), The method comprises at least the following steps: a) providing an apparatus (7) for laminating by induction, comprising at least a first plate (8) and a second plate (9) and an induction device (10); b) placing a stack (6) of components between said first plate (8) and said second plate (9); c) pressing the laminate (6) along the stacking direction (5) with the first and second plates (8, 9); d) activating said induction device (10) to heat at least one separator layer (4) to form an adhesive bond between the separator layer (4) and the electrode (2); e) pulling said first and second plates (8, 9) away from each other; f) removing the laminated component from the device (7); Including, The method, wherein each of the first and second plates (8, 9) is configured as an inductor (16) or has at least one inductor (16).

2. 2. The method according to claim 1, wherein the laminate (6) comprises a plurality of electrodes (2) of the first electrode type (3), a plurality of electrodes (2) of a second electrode type (11), and one separator layer (4) disposed between each electrode (2).

3. 2. The method of claim 1, wherein the stack (6) comprises at least 10 electrodes (2) of one electrode type (3, 11).

4. 3. The method of claim 2, wherein at least some of the separator layers (4) are bonded to each other.

5. All the separator layers (4) are bonded to each other, The laminate (6) has only one integrally formed separator material (12), The method of claim 4.

6. 2. The method according to claim 1, wherein the at least one separator layer (4) extends to surround the stack (6), thereby being disposed between the stack (6) and the first plate (8) and between the stack (6) and the second plate (9) in steps b) to e).

7. At least one electrode (2) has a support material (13) and a coating (15) comprising an active material on at least one surface (14) of the support material (13), the coating (15) is disposed within the laminate (6) between the support material (13) and the separator layer (4); the induction device (10) is driven so that the support material (13) is heated by induction, and the support material (13) heats the at least one separator layer (4) by thermal conduction; The method of claim 1.

8. The method of claim 1, wherein at least one of the first and second plates (8, 9) comprises a plurality of inductors (16).

9. An apparatus (7) for laminating components of a battery cell (1), comprising: The device (7) is adapted to carry out at least steps b) to e) of the method according to any one of claims 1 to 8, The device (7) further comprises at least a first plate (8), a second plate (9) and a guide device (10); Device (7).

Images