Method for producing cylindrical battery cell for traction battery of motor vehicle, and cylindrical battery cell

Abstract

The invention relates to a method for producing a cylindrical battery cell (10) for a traction battery of a motor vehicle, in which an electrode roll (12) is wound (V1), on a first end side of which a cathode contact region (18) is arranged and on a second end side of which opposite the first end side an anode contact region (20) is arranged, the cathode contact region (18) and the anode contact region (20) are flattened (V2) on the respective end sides, a cathode current collector plate (22) is welded (V3) to the flattened cathode contact region (18), a housing cover (24) is directly welded (V4) to the flattened anode contact region (20), the electrode roll (12) is inserted (V5) into a housing cylinder (26), and the housing cylinder (26) is inserted (V6) into the housing cylinder (26). The cathode current collector plate (22) is electrically connected (V6) to the anode (28) of the housing cylinder (26), and the housing cover (24) is connected (V7) to the housing cylinder (26).

Description

Field of the Invention

[0001] The present invention relates to a method for manufacturing a cylindrical battery cell for a traction battery of a motor vehicle and to a cylindrical battery cell for a traction battery of a motor vehicle. Background Art

[0002] US9805877B2 discloses an energy storage device having an electrode roll and current collectors disposed on respective end sides of the electrode roll.

[0003] A battery cell having an electrode roll is also known from EP2476156B1. The electrode roll is placed in a container. Current collector disks are disposed on opposite end portions of the electrode roll. The negative and positive current collector disks serve as internal connections, wherein the negative current collector disk is electrically connected to the negative electrode and the positive current collector disk is electrically connected to the positive electrode. The housing may include a lid and a can. The lid and the can serve as external connections. The negative current collector disk includes a tab for connecting the negative current collector disk to the lid. The positive current collector disk is welded or otherwise electrically connected to the can. Summary of the Invention

[0004] The object of the present invention is to provide a solution that allows the manufacture of a particularly compact battery cell that can be charged particularly quickly.

[0005] This object is solved according to the invention by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the dependent claims, the description and the drawings. Features, advantages and possible embodiments set forth in the scope of the description for one of the subjects of the independent claims are at least similarly to be regarded as features, advantages and possible embodiments of the corresponding subjects of the other independent claims and of each possible combination of the subject of the independent claim, where appropriate in combination with one or more of the dependent claims.

[0006] The present invention relates to a method for manufacturing a cylindrical battery cell for a traction battery of a motor vehicle. The traction battery of the motor vehicle particularly includes a plurality of cylindrical battery cells, which may be, for example, so-called lithium-ion battery cells. The cylindrical battery cell is a round cell. The motor vehicle can be electrically driven by means of electrical energy from the traction battery. Thus, the motor vehicle is in particular an electric vehicle or a hybrid vehicle.

[0007] It is stipulated in the method that a multi-layer film is wound into an electrode roll, the multi-layer film having at least one cathode of film-like structure and at least one anode of film-like structure, the cathode having a film-like cathode contact area electrically connected thereto, and the anode having a film-like anode contact area electrically connected thereto. This means that the cathode configured in film form and the anode configured in film form, which are electrically insulated from each other by at least one separator in the multi-layer film, are wound together around a winding axis, thereby producing an electrode roll. This winding axis coincides with the longitudinal direction of the electrode roll. The cathode contact area is arranged on the first end side of the electrode roll and the anode contact area is arranged on the second end face of the electrode roll opposite to the first end side. The anode can be electrically contacted through the anode contact area, and the cathode can be electrically contacted through the cathode contact area. By arranging the anode contact area and the cathode contact area on the respective opposite end sides of the electrode roll, the risk of direct electrical contact between the cathode and the anode and thus the risk of short circuit can be kept particularly small.

[0008] It is further stipulated in the method that the cathode contact area and the anode contact area are flattened on the respective end sides. For flattening, the respective contact areas are bent, thereby producing a cathode contact surface or an anode contact surface on each end side. When the cathode contact area or the anode contact area is deformed, the respective contact areas (which protrude due to winding on the respective end sides of the electrode roll) are flattened in the axial direction, thereby shortening the longitudinal extension direction of the electrode. In addition, when the respective contact areas are pressed tightly on the end sides, the orientation of the respective contact areas is changed by this flattening. The contact surfaces produced by the flattening of the contact areas can be contacted particularly simply with the respective positive electrode or the respective negative electrode of the battery cell, whereby current can flow particularly well into and out of the battery cell.

[0009] It is also stipulated in this method that a cathode current collector plate is welded onto the flattened cathode contact area. The cathode current collector plate is configured as a collector plate that collects current and conducts the current further in a collecting manner. By means of the cathode current collector plate, the cathode can be electrically contacted particularly well through the flattened cathode area. It is also stipulated in this method that a housing cover is welded directly onto the flattened anode contact area. This means that no anode current collector plate is provided, but instead, the housing cover is directly placed on the flattened anode contact area, welded to this anode contact area, and thus conductively connected. Since no anode current collector plate is provided in the cylindrical battery cell, there is a particularly small contact resistance on the side of the anode contact area, whereby particularly rapid charging and discharging of the cylindrical battery cell can be achieved. In addition, the cylindrical battery cell has a particularly small height based on the direct contact between the flattened anode contact area and the housing cover and is thus designed particularly compactly. Therefore, the preset structural space can be utilized particularly well and a particularly large number of battery cells can be filled based on a particularly compact design concept. Thus, the preset structural space can be used for a particularly large storage capacity.

[0010] It is also stipulated in this method that the electrode roll is inserted into the housing cylinder, and the cathode current collector plate is electrically connected to the positive pole of the housing cylinder. This means that the electrode roll is inserted into the housing cylinder in advance with the first end side on which the cathode current collector plate is arranged, whereby the cathode current collector plate is in electrical contact with the positive pole on the inner side of the housing cylinder. The positive pole is particularly arranged on the side of the housing cylinder opposite to the opening of the housing cylinder. Thus, in the state where the electrode roll is inserted into the housing cylinder, the anode contact area is oriented towards the end of the housing cylinder having the opening. Thus, the anode contact area or the housing cover welded directly onto the anode contact area can be seen through the unclosed opening of the housing cylinder. It is stipulated in this method that finally the housing cover is connected to the housing cylinder. Thereby, electrical contact between the anode contact area and the negative pole of the cylindrical battery cell is achieved. Thus, within the scope of this method, a particularly compactly designed cylindrical battery cell can be manufactured particularly simply.

[0011] In a possible improvement of the present invention, it is provided that the cathode contact region extends as a continuous region along the first side of the multilayer film and the anode contact region extends as a continuous region along the second side of the multilayer film opposite to the first side. When the respective continuous regions are flattened, these continuous regions are deformed towards the central axis of the electrode roll. This means that the respective contact regions on the end sides of the electrode roll are bent radially from the outside to the inside. Thereby, the sections of the respective contact regions arranged in different winding layers of the electrode roll abut against each other and are thereby in electrical contact with each other. Thus, large contact surfaces are produced on the respective end sides of the electrode roll. This large contact surface can be welded particularly well to the cathode current collector plate or directly to the housing cover. Since the respective continuous contact regions extend on the respective opposite sides of the multilayer film, the respective regions of the contact regions are particularly well interleaved at the respective end sides when flattened. Therefore, the contact regions are particularly well held in the respective flattened state in the form of contact plates. Thereby, a return deformation of the contact regions can be particularly well avoided.

[0012] In an alternative possible design of the present invention, it is provided that the cathode contact region and the anode contact region are each divided into a plurality of flags, and the flags are partially stacked when flattened. In order to provide a plurality of flags for the anode contact region or the cathode contact region, the respective sides of the multilayer film provided with the respective contact regions can be cut several times, in particular with at least substantially parallel cross-sections, thereby forming the flags on the respective sides of the multilayer film. By means of the design of the respective contact regions with flags, for flattening, these flags can be bent successively radially towards the central axis of the electrode roll. Thereby, these flags are arranged in a flower shape and are at least partially stacked, so that the flags can be placed particularly flat on the respective end sides. Therefore, an electrode roll with a particularly small height along the longitudinal extension direction can be provided. Thus, a particularly compact battery cell can be manufactured within the scope of this method.

[0013] In a further possible design of the present invention, it is provided that the housing cover is welded to the housing cylinder. Herein, in particular, a helium-tight welding of the housing cover to the housing cylinder is achieved. By means of the welding, the housing cover is held particularly reliably on the housing cylinder and moreover there is particularly good electrical contact between the housing cover and the housing cylinder. In addition, the housing formed by the housing cover and the housing cylinder is particularly stably constructed due to the welding of the housing cover to the housing cylinder.

[0014] In a further possible design of the present invention, it is provided that the cathode current collector plate is welded to the positive electrode. By welding the cathode current collector plate to the positive electrode, the cathode current collector plate is particularly reliably connected to the positive electrode. Therefore, the risk of loosening of the cathode current collector plate and thus the risk of detachment of the electrical contact between the cathode current collector plate and the positive electrode can be kept particularly small.

[0015] In a further possible design of the present invention, it is provided that the core is axially inserted into the electrode roll in a centered manner. The core may have a continuous opening extending in the axial direction, which opening is provided for guiding the gas generated during thermal breakdown of the battery cell to the corresponding end side of the battery cell. Thereby, the gas generated in the case of thermal breakdown of the battery cell can be removed from the battery cell particularly quickly. In addition, the core may be provided for stabilizing the shape of the electrode roll. In particular, when the cathode or anode and thus the electrodes of the electrode roll are deformed during the service life of the battery cell, the deformation of the electrodes can be limited and thus defined by the core. The core may be oriented such that it at least partially surrounds the channel extending in the axial direction through the electrode roll on the circumferential side and thus remains free of multilayer films, so that the gas generated in the case of thermal breakdown of the battery cell can be guided particularly reliably in the channel to the corresponding end of the battery cell. The core may also be referred to as a so-called mandrel.

[0016] In a further possible design of the present invention, it is provided that the housing cover is welded to the flattened anode contact area by means of at least one wave-shaped weld seam. By the wave-shaped design of the weld seam, a particularly large number of different areas of the corresponding contact areas in the different winding layers of the electrode roll can be welded to the housing cover by means of the weld seam and thus reliably connected to the housing cover. Thus, a particularly reliable mechanical and electrical contact is established between the anode contact area and the housing cover. Thereby, the risk of the housing cover becoming detached from the anode contact area can be kept particularly small.

[0017] In a possible improvement of the present invention, it is provided that the wave shape of the weld seam is selected to be sinusoidal. Due to the sinusoidal shape of the weld seam, a sudden change in the direction of the weld seam can be avoided. Thus, the welding device can be guided continuously, especially at a uniform speed, when manufacturing the weld seam. Therefore, the weld seam has particularly few weak positions and can achieve a particularly reliable connection between the housing cover and the anode contact area.

[0018] In a further possible design of the present invention, it is provided that the housing cover is welded to the flattened anode contact area by means of a plurality of wave-shaped weld seams, wherein the plurality of wave-shaped weld seams are arranged evenly at intervals from each other on the circumference of the housing cover. For example, the plurality of wave-shaped weld seams may form a circle interrupted a number of times according to the number of weld seams along the circumferential shape of the end side of the electrode roll. Thereby, on the one hand, it is possible to achieve that the housing cover is held particularly well on the anode contact area over its entire circumference and, in addition, to keep the mechanical load on the respective weld seams particularly small. This small mechanical load is generated by the weld seam interruptions on the circumferential side at the end side, which enables the deformation of the electrodes of the electrode roll during the service life of the battery cell.

[0019] The invention also relates to a prismatic battery cell for a traction battery of a motor vehicle. The traction battery in particular comprises a plurality of prismatic battery cells. The prismatic battery cells are in particular manufactured within the scope of a method as described in connection with the method for manufacturing prismatic battery cells according to the invention. The prismatic battery cell comprises an electrode roll wound from a multilayer film. The multilayer film has at least one membranous cathode and a corresponding membranous anode, the cathode having a membranous cathode contact region electrically connected thereto, and the anode having a membranous anode contact region electrically connected thereto. The cathode contact region is arranged on the first end face of the electrode roll and is flattened. The anode contact region is arranged on the second end face of the electrode roll opposite the first side and is flattened. The prismatic battery cell further comprises a cathode current collector plate which is welded to the flattened cathode contact region. In addition, the prismatic battery cell comprises a housing cover which is directly welded to the flattened anode contact region. Furthermore, the prismatic battery cell has a housing cylinder into which the electrode roll is inserted, the cathode current collector plate being electrically connected, in particular welded, to the positive pole of the housing cylinder, and the housing cover being welded to the housing cylinder. The housing cover is welded to the housing cylinder on the side of the housing cylinder opposite the positive pole.

[0020] Further features of the invention can be derived from the claims, the drawings and the description of the drawings. The features and combinations of features mentioned above in the description and the features and combinations of features shown individually below in the description of the drawings and / or in the drawings can be used not only in the respectively given combinations, but also in other combinations or individually, without departing from the scope of the invention. Description of the Drawings

[0021] The drawings show:

[0022] Figure 1 A schematic process diagram of a method for manufacturing a prismatic battery cell in a corresponding perspective view; and

[0023] Figure 2 A schematic process diagram of a method for manufacturing a prismatic battery cell in a corresponding cross-sectional view. Detailed Description

[0024] In the drawings, the same and functionally identical elements are provided with the same reference numerals.

[0025] In Figure 1 and Figure 2The corresponding method steps of a method for manufacturing a prismatic battery cell 10 for a motor vehicle are shown. The traction battery of the motor vehicle in particular comprises a plurality of prismatic battery cells 10. The battery cell 10 is configured to provide electrical energy for an electric powertrain of the motor vehicle, whereby the motor vehicle can be driven using the electrical energy from the battery cell 10. The battery cell 10 can in particular be part of a high-voltage storage of the motor vehicle.

[0026] The battery cell 10 comprises an electrode coil 12, which is manufactured in a first method step V1 by winding a multilayer film 14 around a winding axis 16. The multilayer film 14 comprises at least one film-shaped anode and at least one film-shaped cathode, which is electrically insulated from the at least one film-shaped anode by means of a separator. A film-shaped cathode contact region 18 is connected to the cathode, and a film-shaped anode contact region 20 is connected to the anode. The cathode contact region 18 and the anode contact region 20 extend along the respective opposite sides of the multilayer film 14, as can be seen in Figure 1 the illustration of the first method step V1.

[0027] After winding the multilayer film 14 around the winding axis 16 to form the electrode coil 12, the anode contact region 20 and the cathode contact region 18 are arranged on the respective opposite end sides of the electrode coil 12. Due to the winding of the multilayer film 14, in the electrode coil 12, the respective contact regions project at least substantially perpendicularly on the respective end sides of the electrode coil 12. In order to form respective contact surfaces on the end sides of the electrode coil 12 for contacting the anode or the cathode via the respectively assigned contact regions, in a second method step V2 the respective contact regions on the end sides of the electrode coil 12 are flattened. Here, the cathode contact region 18 and the anode contact region 20, as can be recognized in Figure 1 the illustration of the first method step V1, are each configured as continuous regions along the respective sides of the multilayer film 14. Alternatively, the cathode contact region 18 or the anode contact region 20 is each divided into a plurality of flags, which are partially superimposed during the flattening.

[0028] When the contact regions configured as continuous regions are flattened, these contact regions each bend radially from the outside to the inside on the end side, whereby the respective different sections of the contact regions arranged on the respective end sides are staggered with one another, such that a continuous contact surface is produced on the respective end side. The respective contact regions to be flattened are shown in combination with Figure 1 the second method step V2 in. In a third method step V3, a cathode collector plate 22 is welded to the flattened cathode contact region 18. In Figure 1In a fourth method step V4, not shown, the housing cover 24 is directly welded to the flattened anode contact area 20. Subsequently, in a fifth method step V5, the electrode coil 12 is inserted into the housing cylinder 26 and in a sixth method step V6 is electrically connected to the positive pole 28 of the housing cylinder 26, here by welding. In a seventh method step V7, the housing cover 24, which is directly welded to the anode contact area 20, is welded to the housing cylinder 26 in order to enclose the housing of the battery cell 10 formed by the housing cover 24 and the housing cylinder 26.

[0029] As can be seen in the illustration of the housing of the battery cell 10 shown in connection with the seventh method step V7, the housing cover 24 is here welded to the anode contact area 20 by means of a plurality of sinusoidally curved weld seams 30. By the design of the waveform of the weld seams 30, the anode contact area 20 is connected to the housing cover 24 in a materially locking manner over a particularly large area. Since the respective weld seams 30 extend on the circumferential side around the winding axis 16 in respective circular sectors on the end side of the electrode coil 12 assigned to the anode contact area 20, the housing cover 24 is held particularly reliably on the anode contact area 20 over its entire circumference and is in particularly reliable electrical contact with the anode contact area 20. Due to the waveform of the weld seams 30, these weld seams contact a particularly large number of different sections of the anode contact area 20, which different sections are formed by different winding layers of the multilayer film 14 around the winding axis 16. Thus, the respective electrons can flow via the anode contact area 20 on a particularly short path between the housing cover 24 and the anode. Thereby, a particularly rapid charging and discharging of the battery cell 10 can be achieved.

[0030] In Figure 2 the method schematic shown, the first method step V1 and the third method step V3 up to the seventh method step V7 are schematically shown in respective sectional views. In Figure 2 the electrode coil 12 produced in the context of the first method step V1 is shown, on the respective end sides of which contact areas 18, 20 are arranged. Furthermore, the third method step V3 is shown, in which the cathode current collector plate 22 is welded to the cathode contact area 18 by means of a laser device, where the welding is indicated by respective arrows 32. Furthermore, in Figure 2 it is shown how in the fourth method step V4 the housing cover 24 is directly welded to the flattened anode contact area 20. Subsequently, in the fifth method step V5, the electrode coil 12 together with the cathode current collector plate 22 welded to the cathode contact area 18 is pushed forward into the housing cylinder 26. Thereafter, in the sixth method step V6 the cathode current collector plate 22 is electrically connected to the positive pole 28 of the housing cylinder 26. For this purpose, the cathode current collector plate 22 can be welded to the positive pole 28, as shown by the arrow 32 associated with the sixth method step V6. In the region of the winding axis 16, as in Figure 2As can be seen, the core 34 can be inserted axially centered into the electrode roll 12, which is not shown due to the options associated with the battery cell 10 to be produced. The core 34 extends axially in the insertion direction along its longitudinal extension direction into the electrode roll 12. In the seventh method step V7, the housing cover 24 is welded to the housing cylinder 26, thereby completing the production of the battery cell 10. Subsequently, a final inspection of the battery cell 10 can be carried out.

[0031] For the production of the battery cell 10, the electrode roll 12 can first be inserted into the housing cylinder 26, then the core 34 can be inserted axially centered into the electrode roll 12, and then the cathode current collector plate 22 can be welded to the positive electrode 28. The described battery cell 10 can be produced particularly quickly based on the described method, since the welding of the current collector plate of the anode to the anode contact area 20 is omitted. In addition, a particularly high volumetric utilization of the structural space can be achieved in the described battery cell 10.

[0032] The described method enables the production of the battery cell 10 in a particularly small production line with a particularly small number of components and thus particularly cost-effectively. In addition, the battery cell 10 enables a particularly high volumetric utilization of the available structural space and a particularly small weight of the battery cell 10. Due to the particularly small number of sequential production steps, the battery cell 10 can be produced particularly quickly or a particularly large number of battery cells 10 can be produced within a given time period.

[0033] Overall, the present invention shows how the battery cell 10 can be realized together with the housing cover 24 that can be directly laser-welded.

[0034] List of reference signs

[0035] 10 Battery cell

[0036] 12 Electrode roll

[0037] 14 Multilayer film

[0038] 16 Winding axis

[0039] 18 Cathode contact area

[0040] 20 Anode contact area

[0041] 22 Cathode current collector plate

[0042] 24 Housing cover

[0043] 26 Housing cylinder

[0044] 28 Positive electrode

[0045] 30 Weld seam

[0046] 32 Arrow

[0047] 34 cores

[0048] Method steps corresponding to V1 - V7

Claims

1. A method for manufacturing a cylindrical battery cell (10) for a traction battery of a motor vehicle, wherein, a multilayer film (14) is wound (V1) into an electrode roll (12), the multilayer film having at least one film-shaped cathode and at least one film-shaped anode, the cathode having a film-shaped cathode contact area (18) electrically connected to the cathode, the anode having a film-shaped anode contact area (20) electrically connected to the anode, the cathode contact area (18) being arranged on a first end side of the electrode roll and the anode contact area (20) being arranged on a second end side of the electrode roll opposite to the first end side, the cathode contact area (18) and the anode contact area (20) are flattened (V2) on respective end sides, a cathode current collector plate (22) is welded (V3) onto the flattened cathode contact area (18), a housing cover (24) is directly welded (V4) onto the flattened anode contact area (20), the electrode roll (12) is inserted (V5) into a housing cylinder (26), the cathode current collector plate (22) is electrically connected (V6) to a positive electrode (28) of the housing cylinder (26), and the housing cover (24) is connected (V7) to the housing cylinder (26).

2. The method according to claim 1, characterized in that, the cathode contact area (18) extends as a continuous area along a first side of the multilayer film (14), and the anode contact area (20) extends as a continuous area along a second side of the multilayer film (14) opposite to the first side, and during the flattening, the respective continuous areas are deformed towards the central axis of the electrode roll (12).

3. The method according to claim 1, characterized in that, the cathode contact area (18) and the anode contact area (20) are each divided into a plurality of flag-shaped pieces, and the flag-shaped pieces are locally stacked during the flattening.

4. The method according to any one of the preceding claims, characterized in that, the housing cover (24) is welded to the housing cylinder (26).

5. The method according to any one of the preceding claims, characterized in that, the cathode current collector plate (22) is welded to the positive electrode (28).

6. The method according to any one of the preceding claims, characterized in that, a core (34) is axially inserted centrally into the electrode roll (12).

7. The method according to any one of the preceding claims, characterized in that, the housing cover (24) is welded to the flattened anode contact area (20) by means of at least one corrugated weld (30).

8. The method according to claim 7, characterized in that, the weld (30) is sinusoidal in shape.

9. The method according to claim 7 or 8, characterized in that, a plurality of corrugated welds (30) are provided, which are arranged evenly spaced apart and distributed on the circumference of the housing cover (24).

10. A cylindrical battery cell (10) for a traction battery of a motor vehicle, the battery cell having: An electrode roll (12) formed by winding a multi-layer film (14), the multi-layer film having at least one film-like cathode and at least one film-like anode, the cathode having a film-like cathode contact area (18) electrically connected to the cathode, and the anode having a film-like anode contact area (20) electrically connected to the anode, wherein, The cathode contact area (18) is arranged and flattened on the first end side of the electrode roll (12), and the anode contact area (20) is arranged and flattened on the second end side of the electrode roll (12) opposite to the first side, A cathode current collector plate (22) welded to the flattened cathode contact area (18), A housing cover (24) directly welded to the flattened anode contact area (20), A housing cylinder (26) into which the electrode roll (12) is inserted, the cathode current collector plate (22) being electrically connected to the positive electrode (28) of the housing cylinder, and the housing cover (24) being welded to the housing cylinder.

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