METHOD AND APPARATUS FOR PRODUCING AN ELECTRODE STACK

Abstract

The invention relates to a method for producing an electrode stack made of anodes and cathodes for a lithium-ion battery, in particular of an electrically powered motor vehicle, wherein the anodes or the cathodes are provided with a separator, wherein the anodes and the cathodes are conveyed into receiving areas of a rotationally driven or rotatably driven stacking wheel; wherein the anodes and cathodes received in the receiving areas are conveyed to a stacking compartment by rotation of the stacking wheel; wherein the anodes and the cathodes are held in the region of the stacking compartment by a removal arm and are transferred from the respective receiving areainto the stacking compartment as a result of the rotation of the stacking wheel, wherein said anodes and cathodes are stacked in an alternating manner in the stacking compartment; and wherein the alternately stacked anodes and cathodes are pressed against one another in the stacking compartment. The invention additionally relates to a device for producing such an electrode stack.

Claims

1. A method for producing an electrode stack from anodes and cathodes for a lithium-ion battery, in particular for an electrically powered motor vehicle, wherein the anodes or the cathodes are provided with a separator, comprising: conveying the anodes and the cathodes into receptacles of a rotationally driven or rotationally drivable stacking wheel, conveying the anodes and the cathodes accommodated in the receptacles are conveyed to a stacking compartment by means of a rotation of the stacking wheel, holding the anodes and the cathodes by means of a stripper arm in the region of the stacking compartment, and transferring the anodes and cathodes due to the rotation of the stacking wheel from the respective receptacles into the stacking compartment, wherein the anodes and the cathodes are stacked alternately in the stacking compartment, and pressing the alternately stacked anodes and cathodes against each other in the stacking compartment.

2. The method according to claim 1, wherein at least one of the anodes and at least one of the cathodes are conveyed simultaneously into the corresponding receptacles of the stacking wheel.

3. The method according to claim 1, wherein a speed at which the anodes and the cathodes are conveyed into the respective receptacles of the stacking wheel is adjusted in such a way that the anodes and the cathodes, before they are stopped by the stripper arm, are decelerated to a standstill due to friction relative to the given receptacle.

4. An apparatus for producing an electrode stack of anodes and cathodes, for a lithium-ion battery, comprising a stacking wheel which can be driven to rotate about an axis of rotation, with receptacles for the anodes and the cathodes which are formed on the circumference and which extend in an axial direction, a conveying device for conveying the anodes and the cathodes into the receptacles of the stacking wheel, a stripper arm which can be inserted into a recess that is continuous in the circumferential direction of the stacking wheel, and which forms a stop for the anodes and the cathodes accommodated in the receptacles when the stacking wheel rotates, such that the anodes and the cathodes are transferred from the respective receptacles into a stacking compartment due to the rotation of the stacking wheel, or two stripper arms which are arranged in the axial direction on both sides of the stacking wheel, wherein the stacking wheel has a smaller extension in the axial direction than the anodes and the cathodes, such that the stripper arms form a stop for the anodes and the cathodes accommodated in the receptacles and protruding in the axial direction from the receptacles when the stacking wheel rotates, and wherein the anodes and the cathodes are transferred from the respective receptacles into a stacking compartment due to the rotation of the stacking wheel, and wherein the stacking compartment has a compression unit for generating a pressing force on the anodes and cathodes stacked in the stacking compartment and/or on the monocells stacked in the stacking compartment.

5. The apparatus according to claim 4, wherein the receptacles are arcuate in a plane perpendicular to the axis of rotation.

6. The apparatus according to claim 5, wherein each conveying device for conveying the anodes into the receptacles of the stacking wheel and for conveying the cathodes into the receptacles has at least one first conveyor belt.

7. The apparatus according to claim 6, wherein each of the first conveyor belts is assigned a second conveyor belt oriented in parallel, with a direction of rotation opposite to the assigned first conveyor belt, such that the anodes and/or the cathodes are clamped during their conveying process between the first conveyor belt and the second conveyor belt.

8. The apparatus according to claim 7, wherein the first conveyor belts and/or the second conveyor belts protrude into the or a recess of the stacking wheel, such that the anodes and the cathodes are conveyed tangentially into the receptacle.

9. The apparatus according to claim 4, wherein, for removing the electrode stack, the stacking compartment together with the compression unit, can be moved and/or tilted about a tilting axis parallel to the axis of rotation.

10. The apparatus according to claim 4, wherein each of the slides of the stacking compartment, and/or the stripper arm, provided for orienting the anodes and the cathodes in alignment with each other, has a contacting recess for electrical contacts of the anodes and the cathodes.

Description

[0034] Embodiments of the invention are explained in more detail below with reference to the drawings, wherein:

[0035] FIG. 1 schematically shows a first variant of an apparatus for producing an electrode stack, having a stacking wheel that can be driven to rotate about an axis of rotation, with receptacles for the anodes and the cathodes, wherein a stripper arm is inserted into a circumferentially continuous recess of the stacking wheel, and by means of this the anodes and the cathodes can be transferred from the receptacles into a stacking compartment,

[0036] FIG. 2a schematically shows the first variant of the apparatus in a side view, viewed perpendicular to the axis of rotation,

[0037] FIG. 2b schematically shows the first variant of the apparatus in a plan view,

[0038] FIG. 3a shows a second variant of the apparatus in a side view, viewed perpendicular to the axis of rotation of its rotationally driven stacking wheel, wherein a stripper arm is arranged in front of the stacking wheel, and another stripper arm is arranged behind the stacking wheel with respect to a direction parallel to the axis of rotation, and these serve as a stop for the anodes and the cathodes conveyed by means of the receptacles of the stacking wheel,

[0039] FIG. 3b schematically shows the second variant of the apparatus in a plan view, and

[0040] FIG. 4 shows a method sequence for producing the electrode stack, in a flowchart.

[0041] Corresponding parts and dimensions are always provided with the same reference signs in all figures.

[0042] In FIG. 1 and FIGS. 2a and 2s, a first variant of an apparatus 2 is shown, which is used to produce an electrode stack 4 made of anodes 6 and cathodes 8.

[0043] The anodes 6 and the cathodes 8 are sheet-shaped, the cathodes 8 being laminated with a separator which, for the sake of improved clarity, is not shown further in FIGS. 1 to 3b. Furthermore, the anodes 6 and the laminated cathodes 8 each have an electrical contact 10, the same also being referred to as a tab. The anodes 6 each have the same extension with respect to a plane spanned by them as each of the laminated cathodes 8 in a plane spanned by the same, optionally with the exception of their electrical contacts 10.

[0044] The electrode stack 4 is intended for a lithium-ion battery (not shown in further detail), for example for a (traction) battery of an electrically powered motor vehicle. The apparatus 2 has a stacking wheel 12 which can be driven to rotate about an axis of rotation D.

[0045] The stacking wheel 12 has receptacles 14 for the anodes 6 and for the cathodes 8 formed on the circumference thereof and extending in the axial direction A, that is to say along the axis of rotation D. The receptacles 14 are formed by means of arms 16, which are also referred to as blades, which extend from the region of the axis of rotation D to the circumferential side of the stacking wheel 12—that is to say, outward. The arms 16, and thus also the receptacles 14, are designed in a spiral shape in a plane perpendicular to the axis of rotation D. The receptacles 14 therefore have a spiral cross-section in this plane. In this case, a curvature of the arcuate receptacle increases from the circumferential side toward the axis of rotation D—that is to say, as the radial distance from the axis of rotation D becomes smaller. Furthermore, the receptacles 14 extend outward opposite the direction of rotation of the stacking wheel 12 represented by a corresponding arrow about the axis of rotation D.

[0046] The stacking wheel 12 has a wall 18 at each end with respect to the axial direction A, which wall delimits the receptacles 14. In this case, the front wall 18 in the viewing direction is not shown in FIG. 1 for the purpose of visibility. The wall 18 prevents an undefined displacement of the anodes 6 and the cathodes 8 in a direction along the axis of rotation D during the rotation of the stacking wheel 12, and during the process of the anodes 6 and the cathodes 8 being received in the receptacles 14.

[0047] As can be seen in particular in FIGS. 2a and 2b, the stacking wheel 12 has a circumferential recess 20 which is continuous in the circumferential direction of the stacking wheel 12. The recess 20 thus extends in a plane perpendicular to the axis of rotation D. The recess 20 also has an extension opposite the radial direction R to the axis of rotation D, which is greater than the extension of the receptacles 14 in this direction. The arms 16 are therefore not continuous in the axial direction A.

[0048] A stripper arm 22 is arranged in the recess 20. The section of the stripper arm 22 which is arranged within the recess 20 is shown with dashed lines in FIG. 1. The stripper arm 22 serves as a stop for the anodes 6 and the cathodes 8 accommodated in the receptacles 14. Upon the rotation of the stacking wheel 12, the anodes 6 and the cathodes 8 arranged in the receptacles 14 are displaced relative to the stripper arm 22, such that they are held against further conveyance by means of the stacking wheel 12. Due to the further rotation of the stacking wheel 12, each of the anodes 6 and the cathodes 8 are transferred from the respective receptacles 14 into a stacking compartment 24 arranged in the region of the stripper arm 22.

[0049] The stacking compartment 24 has a slide 26 for orienting the anodes 6 and the cathodes 8 in alignment with each other. For this purpose, it is able to move in the direction of the stripper arm 22. This movement is shown in FIG. 1 by means of a double arrow. Furthermore, the stacking compartment 24 has a compression unit 28 for generating a pressing force on the anodes 6 and the cathodes 8 stacked in the stacking compartment 24 and aligned with each other. For this purpose, the compression unit 28 can be pivoted through the recess 20. The electrode stack 4 is formed by orienting the electrodes 6 and 8 in alignment with each other and pressing them together.

[0050] According to a variant of the stacking compartment 24, not shown, the compression unit 28 is adjustable in the axial direction A, such that the compression unit 28 cannot be pivoted through the recess 20, but can be moved between the stacking wheel 12 and a bottom 29 of the stacking compartment 24.

[0051] The stacking compartment 24 can also be tilted, together with the compression unit 28 and with the stripper arm 22, about a tilting axis K oriented parallel to the axis of rotation D, such that the electrode stack 4 can be removed from the stacking compartment and transported away by means of a conveyor belt 30. By means of the conveyor belt 30, the electrode stack 4, that is to say the electrodes 6 and 8 pressed against each other, can be transported for further production of the battery, or to a magazine or a storage.

[0052] In FIG. 1, the apparatus 2 is shown, with a viewing direction along the axis of rotation D; and in FIGS. 2a and 2b, it is shown with a viewing direction perpendicular to the axis of rotation D and parallel or perpendicular to the bottom 29 of the stacking compartment 24. The stripper arm 22 is shown in simplified form in FIGS. 2a and 2b for the purpose of improved clarity.

[0053] As can be seen in particular in FIG. 2b, the slide 26 and the stripper arm 22 each have a contacting recess 32 for the electrical contacts 10 of the anodes 6 and the cathodes 8.

[0054] Furthermore, the apparatus 2 has a conveying device 34 for conveying the anodes 6 and the cathodes 8 into the receptacles 14 of the stacking wheel 12. The conveyor 34 has two first conveyor belts 36, wherein one of the first conveyor belts 36 only conveys the anodes 6 into the receptacle 14 of the stacking wheel 12, and the other of the first conveyor belts 36 conveys the cathodes into the receptacles 14 of the stacking wheel 12. Furthermore, each of the first conveyor belts 36 is assigned a second conveyor belt 38, wherein each conveyor belt 38 is arranged parallel to the first conveyor belt 36 it is assigned to. Each of the conveyor belt surfaces 40 of the second conveyor belts 38 has an opposite direction of rotation to the conveyor belt surface 40 of the assigned first conveyor belt 36. The first conveyor belts 36 and the assigned second conveyor belts 38 are each spaced apart from each other in such a way that the anodes 6 and the cathodes 8 are clamped between the first conveyor belt 36 and the corresponding second conveyor belt 38 when they are conveyed.

[0055] The first conveyor belts 36 protrude partially into the recess 20 of the stacking wheel 12, such that the anodes 6 and the cathodes 8 are conveyed tangentially into the receptacle 14. Those portions of the conveyor belts 36 and 38 which protrude into the recess 20 are shown in dashed lines.

[0056] As can be seen in particular in FIG. 2a, the first conveyor belts 36 and the second conveyor belts 38 have a smaller extension than the anodes 6 and the cathodes 8 in a direction which runs perpendicular to the conveying direction and in the planes spanned by their conveyor belt surfaces 40. In other words, the electrodes 6 and 8 protrude beyond the two conveyor belts 38 in the transverse direction of the conveyor belt.

[0057] A second variant of the apparatus 2 is shown in FIGS. 3a and 3b. With the exception of what is discussed below, the explanations given above apply analogously to the second variant, and are not shown in further detail here.

[0058] The apparatus 2 has two stripper arms 22 which are arranged in the axial direction A on both sides of the stacking wheel 12. In other words, one of the two stripper arms is arranged with respect to the axial direction A in front of the stacking wheel 12, and the other stripper arm 22 is arranged behind it. The stacking wheel 12 in this case has a smaller extension in the axial direction A, such that the anodes 6 and the cathodes 8 accommodated in the receptacles 14 protrude in the axial direction A on both sides beyond the stacking wheel 12. When the stacking wheel 12 rotates, the two stripper arms 22 form a stop for the anodes 6 and the cathodes 8 accommodated in the receptacles 14. The anodes 6 and cathodes 8 are consequently supported against further conveyance due to the rotation of the stacking wheel 12, and are transferred from the given receptacle 14 into the stacking compartment 24.

[0059] In comparison to the first variant, the stacking wheel 12 does not have a wall 18 which closes off the receptacles 14 at the ends with respect to the axial direction A.

[0060] The stripper arms 22 still have no contacting recess 32 for the electrical contacts 10 of the anodes or the cathodes. Rather, the electrical contacts 10 are arranged between the arms 16 of the stacking wheel.

[0061] The flow diagram shown in FIG. 4 illustrates a method for producing an electrode stack 4 from the anodes 6 and the cathodes 8. An apparatus 2 according to FIGS. 1 and 2 is preferably used for this purpose.

[0062] In a first step I, the anodes 6 and the cathodes 8 are conveyed into the receptacles 14 of the stacking wheel 12, which is driven to rotate—in particular continuously. In this case, at least one of the anodes 6 and at least one of the cathodes 8 are simultaneously conveyed into the given receptacle 14 of the stacking wheel 12. For this purpose, the apparatus 2, as explained above, has a first conveyor belt for the anodes 6 and a further first conveyor belt 36 for the cathodes 8.

[0063] In this case, only a single cathode 8 or a single anode 6 is received in each of the receptacles 14, the anodes 6 and the cathodes 8 being introduced alternately into the receptacles 14 which follow one another with respect to the circumferential direction (direction of rotation) of the stacking wheel 12.

[0064] The electrical contacts 10 of the anodes 6 are arranged at the front with respect to their conveying direction into the given receptacle 14 of the stacking wheel 12, and the electrical contacts 10 of the cathodes are arranged at the rear with respect to their conveying direction. In this way, the electrical contacts 10 of the anodes 6 and the cathodes 8 are arranged on opposite sides of the electrode stack 4.

[0065] In a second step II, the anodes 6 and the cathodes 8 accommodated in the receptacles 14 are conveyed to a stacking compartment 24 by means of a rotation of the stacking wheel 12.

[0066] In a third step III of the method, the anodes 6 and the cathodes 8 are held in the region of the stacking compartment 24 by means of the stripper arm 22 or by means of the stripper arms 22. As such, the anodes 6 and the cathodes 8 are held (supported) against the rotation of the stacking wheel 12 by means of the stripper arm 22 or by means of the stripper arms 22, such that the given receptacle 14 is displaced relative to the associated electrode 6 and/or 8 due to the rotation of the stacking wheel 12, and the electrode 6 and/or 8 is accordingly transferred out of the given receptacle 14 into the stacking compartment 24. The anodes 6 and the cathodes 8 are alternately stacked one on top of the other in the stacking compartment 24.

[0067] In addition, the first electrode transferred from each receptacle 14 into the stacking compartment 24 is a laminated cathode 8.

[0068] Furthermore, the conveying speed of the anodes 6 and the cathodes 8 into each of the receptacles 14 of the stacking wheel 12 is adjusted in such a way that the anodes 6 and the cathodes 8, before they are stopped by the stripper arm 22 or the stripper arms 22, are decelerated to a standstill relative to the given receptacle, due to friction between the anodes 6 and the cathodes 8 and the given receptacle 14. The conveying speed is adjusted as a function of the shape of the receptacles 14. Due to the spiral shape of the receptacles 14, a frictional force between each receptacle 14 and the electrode 6 or 8 becomes greater toward the end (at the axis of rotation) of the receptacle 14 facing the axis of rotation D.

[0069] In a fourth step IV, the alternately stacked anodes 6 and cathodes 8 in the stacking compartment 24 are aligned with each other by means of the slide 26, and are pressed against each other by means of the compression unit 28, forming the electrode stack 4. For this purpose, the compression unit 28 acts with a pressing force on the anodes 6 and the cathodes 8 stacked in the stacking compartment 24 and aligned with each other.

[0070] The invention is not limited to the embodiment described above. Rather, other variants of the invention can also be derived therefrom by a 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 embodiments can also be combined with each other in other ways without departing from the subject matter of the invention.

LIST OF REFERENCE SIGNS

[0071] 2 apparatus [0072] 4 electrode stack [0073] 6 anode [0074] 8 cathode [0075] 10 electrical contact of the electrode [0076] 12 stacking wheel [0077] 14 receptacle [0078] 16 arm [0079] 18 wall [0080] 20 recess [0081] 22 stripper arm [0082] 24 stacking compartment [0083] 26 slide [0084] 28 compression unit [0085] 29 bottom of the stacking compartment [0086] 30 conveyor belt [0087] 32 contacting recess [0088] 34 conveying direction [0089] 36 first conveyor belt [0090] 38 second conveyor belt [0091] 40 conveyor belt surface [0092] I. Conveying the cathodes and the anodes into the receptacles of the stacking wheel [0093] II Conveying the cathodes and the anodes to the stacking compartment by means of the stacking wheel [0094] III Transferring the cathodes and the anodes from the receptacle into the stacking compartment [0095] IV Aligning and pressing the cathodes and the anodes against each other [0096] A axial direction [0097] D axis of rotation [0098] K tilting axis