Method and device for producing a pressed battery cell stack

Abstract

The invention relates to a method for producing a pressed battery cell stack (3) which comprises a plurality of prismatic battery cells (4) and cell separating elements (5) arranged therebetween, wherein a plurality of prismatic battery cells (4) are provided and arranged along an axis with an axial gap (7) between the battery cells (4) on a support surface (11).1) a support (11), wherein a height-adjustable support element (16) for a corresponding cell separating element (5) is arranged below the axial spaces (7) between the battery cells (4), wherein a cell separating element (5) is inserted into the spaces (7) between the battery cells (4) until it rests on a support surface (17) of the corresponding support element (16) in such a way that a loose battery cell stack (2) is created, which is then pressed to form a pressed battery cell stack (3), wherein the support elements (16) for the cell separating elements (5) are designed in such a way that the support surface (17) for the lying cell separating elements (5) is reduced in size with little force during the pressing process, and a device (10) for carrying out the method.

Description

The invention relates to a method for producing a pressed battery cell stack. The invention further relates to an apparatus for carrying out such a method.Processes for producing a pressed battery cell stack and corresponding devices for carrying out such a process are known in numerous variations. In the production of battery stacks from prismatic battery cells, cell separating elements are arranged between the battery cells. For an optimal function, these cell separation elements assume a defined position relative to the cell surface. In general, the cell separating elements bear against the battery cells at a circumferential distance from the cell edge. In order to achieve this position within the permitted tolerance limits, the corresponding cell separating element can be adhesively bonded to the corresponding battery cell with the required accuracy. It can be considered disadvantageous in this case that the adhesive bonding of the cell separating elements requires a complicated process for singulating the battery cells and for applying the adhesive layer. In this case, the battery cell is gripped, positioned and transported a number of times. For this purpose, a high area requirement is to be provided and higher individual material costs are to be kept available by the use of adhesive.DE 10 2020 124 738 A1 discloses a method for supporting a battery housing when inserting a battery module. A support device comprises a support device for supporting the battery housing.In this case, the support device has a plurality of mutually movable pin elements for parking the battery housing, wherein a negative shape corresponding to a shape of a bottom underside of a housing bottom of the battery housing is set by means of the pin elements on the basis of a selective displacement of the support device along a predefined translatory movement direction, in that each pin element is displaced from a respective starting position into a respective end position when the bottom underside is reached and is locked at the respective end position by means of a locking unit. After setting the negative mold, the support device is displaced by a defined offset distance opposite to the direction of movement.DE 10 2016 201 605 A1 discloses a battery module having a plurality of battery cells and a method for producing such a battery module. The battery module has a plurality of partitions. In this case, a battery cell is arranged between two dividing walls, and a spring element is furthermore arranged between two dividing walls adjacent to a battery cell, in particular a tension and / or compression spring element, which is arranged in a contacting and / or connected manner to the two dividing walls in such a way that a value of a deformation constant of the spring element determines a force transmitted from the two dividing walls to the battery cell. In this case, the spring elements have different values of a deformation constant which are dependent on the ageing speed of the individual battery cells.DE 10 2020 111 570 A1 discloses a method for producing a traction battery for a motor vehicle and a corresponding production device. The traction battery comprises a plurality of cell stacks, each of which is composed of a plurality of battery cells and a plurality of cell separating elements. Preferably, one of the cell separating elements is arranged between each two of the battery cells. The production device has punches, by means of which a pressing of the cell stack can be carried out. To produce the traction battery, the battery cells of the traction battery are first arranged next to one another and the cell separating elements are introduced between them. Subsequently, the cell stack composed of the battery cells and the cell separating elements is pressed in a pressing direction with the aid of the punches. During the pressing, a specific pressing pressure is set.The invention is based on the object of providing a method for producing a pressed battery cell stack and a device for carrying out the method, which enables a more rapid and cost-effective production of pressed battery cell stacks.This object is achieved by a method for producing a pressed battery cell stack having the features of patent claim 1 and by a device for producing a pressed battery cell stack having the features of patent claim 6. Advantageous embodiments with expedient developments of the invention are specified in the dependent patent claims.In order to provide a method for producing a pressed battery cell stack, which enables a more rapid and cost-effective production of pressed battery cell stacks, a plurality of prismatic battery cells are provided and arranged along an axis with an axial intermediate space between the battery cells on a support surface of a support. Below the axial intermediate spaces between the battery cells, a height-adjustable support element for a corresponding cell separating element is arranged in each case. In the intermediate spaces between the battery cells, a cell separating element is inserted in each case until it rests on a supporting surface of the corresponding supporting element in such a way that a loose battery cell stack is produced, which is subsequently pressed to form a pressed battery cell stack. In this case, the support elements for the cell separation elements are designed such that during the pressing process the support surface for the cell separation elements resting thereon is reduced with low force.In addition, a device for producing a pressed battery cell stack is proposed, which comprises a support with a contact surface, a pressing device and a supporting device with a plurality of supporting elements and is designed to carry out such a method. In this case, the support elements for the cell separation elements are designed such that during the pressing process the support surface for the cell separation elements resting thereon is reduced with low force.A pressed battery cell stack is understood below to mean a stack which comprises a plurality of prismatic battery cells and cell separating elements arranged therebetween. In addition, a plurality of pressed battery cell stacks arranged one behind the other can form a battery module.In embodiments of the invention, the height-adjustable support elements can enable a defined position of the cell separating elements relative to the surface of the battery cells. As a result, the cell separating elements can be arranged on the battery cells without adhesion at a circumferential distance from the edge. The cell separating elements can be loosely inserted, for example, via a multiple gripper into the axial intermediate spaces, which form a sufficiently large distance between the battery cells. The pressed battery cell stack can be simply lifted off the support elements after the pressing.In summary, embodiments of the invention allow a faster manufacturing process and a cost saving as well as lower individual material costs with a lower area requirement and an increased process safety.In an advantageous embodiment of the method, a distance between the support surface of the support elements and the support surface of the support can be adjusted via the height-adjustable support elements. As a result, the position of the cell separating elements in the vertical direction can be adjusted individually and independently of the contact surface of the battery cells.In a further advantageous embodiment of the method, the supporting surfaces of the individual supporting elements can be enlarged again after the removal of the pressed battery cell stack. The support elements of the cell separation elements can be designed such that in the pressed end state only a small force acts, which is caused by the elasticity of the material of the support elements or by a structural design of a restoring mechanism on the support elements and can bring about the enlargement of the support surfaces of the individual support elements.In a further advantageous embodiment of the method, a plurality of pressed battery cell stacks can be produced in one operation. As a result, a corresponding battery module can be realized in a simple manner, which comprises a plurality of pressed battery cell stacks arranged one behind the other. Here, the battery cell stacks may be separated from each other by plates. Individual pressed battery cell stacks can thus be arranged between two end plates. In the case of a battery module, the pressed battery cell stacks can be arranged between two end plates, and a central plate can be arranged in each case between the individual pressed battery cell stacks of the battery module.In an advantageous embodiment of the device, the support device can comprise a sliding device with at least one slide rail, in which the support elements are mounted in a slidably movable manner. The support elements can preferably be mounted on sliding elements and individually pushed along during pressing. For the readjustment, the support elements connected to one another via a return connector can preferably be drawn onto an original stitch dimension by means of an concertina function.In a further advantageous embodiment of the device, the support elements can be designed as elastic support elements, the effective support surface of which can be changed by elastic deformation. In this case, the effective supporting surface can be reduced during the pressing operation by the elastic deformation of the supporting elements. Due to the elasticity of the material of the support elements, a force acts which can bring about the enlargement of the support surfaces of the individual support elements after the pressing. Alternatively, the support elements can be designed as spring-loaded support elements, the effective support surface of which can be changed by a rotation. In this way, the effective supporting surface can be reduced in size against a spring force during the pressing operation. Due to the structural design of the restoring mechanism, a spring force acts on the support elements, which spring force can bring about the enlargement of the support surfaces of the individual support elements after the pressing.In a further advantageous embodiment of the device, the pressing device can comprise two pressing rams, between which a plurality of prismatic battery cells and cell separating elements arranged therebetween can be arranged.The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination but also in other combinations or alone without departing from the scope of the invention. Therefore, embodiments are also to be considered included and disclosed by the invention, which are not explicitly shown or explained in the figures, but which emerge from the explained embodiments and can be generated by separate combinations of features.Exemplary embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. In the drawings, like reference numerals designate components or elements that perform like or analogous functions. The following are shown here: FIG. 1 shows a schematic flow diagram of an exemplary embodiment of a method according to the invention for producing a pressed battery cell stack; FIG. 2 shows a schematic sectional illustration of an exemplary embodiment of a device according to the invention for producing a pressed battery cell stack in a first state; FIG. 3 shows a schematic sectional illustration of the device according to the invention for producing a pressed battery cell stack from FIG. 2 in a second state; FIG. 4 shows a schematic sectional illustration of the device according to the invention for producing a pressed battery cell stack from FIGS. 2 and 3 in a third state; FIG. 5 shows a schematic perspective sectional illustration of a detail of a first exemplary embodiment of a supporting device of the device according to the invention from FIGS. 2 to 4 ; FIG. 6 shows a schematic sectional illustration of the detail of the supporting device from FIG. 5 ; FIG. 7 shows a schematic perspective sectional illustration of a detail of a second exemplary embodiment of a supporting device of the device according to the invention from FIGS. 2 to 4 ; and FIG. 8 shows a schematic sectional illustration of the detail of the supporting device from FIG. 7.As can be seen from FIGS. 1 to 4, the illustrated exemplary embodiment of the method 100 according to the invention for producing a pressed battery cell stack 3, which comprises a plurality of prismatic battery cells 4 and cell separating elements 5 arranged therebetween, comprises a step S 100, in which a plurality of prismatic battery cells 4 are provided and, in a step S 110, are arranged along an axis with an axial intermediate space 7 between the battery cells 4 on a support surface 11.1 of a support 11. In a step S 120, below the axial intermediate spaces 7 between the battery cells 4 a height-adjustable support element 16 for a corresponding cell separating element 5 is arranged in each case. This state of a device 10 according to the invention for producing a pressed battery cell stack 3 is illustrated in FIG. 2. In a step S 130, a cell separating element 5 is inserted in each case in the intermediate spaces 7 between the battery cells 4 until it rests on a supporting surface 17 of the corresponding supporting element 16 in such a way that a loose battery cell stack 2 is produced. This state of the device 10 for producing a pressed battery cell stack 3 is illustrated in FIG. 3. In a step S 140, the loose battery cell stack 2 is subsequently pressed into a pressed battery cell stack 3. This state of the device 10 for producing a pressed battery cell stack 3 is illustrated in FIG. 4. Here, the support elements 16 for the cell separation elements 5 are designed such that during the pressing process the support surface 17 for the cell separation elements 5 resting thereon is reduced with little force.In the illustrated exemplary embodiment of the method 100, in step S 120, a distance measure 19 is set between the support surface 17 of the support elements 16 and the support surface 11.1 of the support 11 via the height-adjustable support elements 16.As can be further seen from FIGS. 2 to 8, the device 10 for producing a pressed battery cell stack 3 comprises a support 11 with a contact surface 11.1, a pressing device 12 and a support device 14 with a plurality of support elements 16 and is designed to carry out the method 100 according to the invention. Here, the support elements 16 for the cell separation elements 5 are designed such that during the pressing process the support surface 17 for the cell separation elements 5 resting thereon is reduced with low force.In the exemplary embodiments shown, the support device 14 comprises a sliding device 15 with at least one slide rail 15.1, in which the support elements 16 are mounted in a slidingly movable manner. As a result, the support elements 16 are individually pushed along during the pressing, as can be seen in particular from FIG. 4. For the readjustment, the support elements 16 connected to one another via a return connector 18 are drawn by means of an concertina function onto the original stitch size of the support device 14 shown in FIGS. 2 and 3.As can be further seen from FIGS. 5 and 6, the support elements 16 in the illustrated first exemplary embodiment of the support device 14A are designed as elastic support elements 16A, the effective support surface 17 of which can be changed by elastic deformation. In FIGS. 5 and 6, the axial interspace 7 between a battery cell 4 shown on the left and a middle battery cell 4 has a distance A between two adjacent battery cells 4 in a loose battery cell stack 2 shown in FIG. 3. The intermediate space 7 between a battery cell 4 shown on the left and the middle battery cell 4 has a distance AP between two adjacent battery cells 4 in a pressed battery cell stack 3 shown in FIG. 4, which is significantly smaller than the distance A in the loose battery cell stack 2.As can be further seen from FIGS. 5 and 6, the support elements 16 designed as elastic support elements 16A have a curved shape in the non-pressed state, which shape is clearly compressed by elastic deformation in the pressed state. The effective supporting surface 17 is significantly reduced by the elastic deformation of the elastic supporting elements 16A during the pressing operation. Due to the elasticity of the material of the elastic support elements 16A, a force acts which, after the pressing and removal of the pressed battery cell stack 3, brings about the enlargement of the support surfaces 17 of the individual elastic support elements 16A.As can be further seen from FIGS. 7 and 8, the support elements 16 in the illustrated second exemplary embodiment of the support device 14B are designed as spring-loaded support elements 16B, the effective support surface 17 of which can be changed by a rotation. Analogously to the exemplary embodiment of the support device 14 illustrated in FIGS. 5 and 6, the axial interspace 7 between the battery cell 4 illustrated on the left and the middle battery cell 4 in the second exemplary embodiment of the support device 14B illustrated in FIGS. 7 and 8 has the distance A between two adjacent battery cells 4 of the loose battery cell stack 2 illustrated in FIG. 3. The intermediate space 7 between the battery cell 4 shown on the left and the middle battery cell 4 has the distance AP between two adjacent battery cells 4 of the pressed battery cell stack 3 shown in FIG. 4, which is significantly smaller than the distance A in the loose battery cell stack 2.As can be further seen from FIGS. 7 and 8, the support elements 16 designed as spring-loaded support elements 16B have a first rotational position in the non-pressed state. During the pressing process, the effective supporting surface 17 is reduced in size into a second rotational position by a rotation of the spring-loaded supporting elements 16B counter to a spring force. The effective support surface 17 is significantly reduced by the rotation of the spring-loaded support elements 16B during the pressing operation. Due to the structural design of the reset mechanism, a spring force acts on the spring-loaded support elements 16B, which causes the enlargement of the support surfaces 17 of the individual spring-loaded support elements 16B after the pressing and removal of the pressed battery cell stack 3.As can be further seen from FIGS. 2 to 4, two pressed battery cell stacks 3 are produced in one operation with the illustrated exemplary embodiment of the device 10, which can form a battery module 1 for a high-voltage battery. In alternative exemplary embodiments not shown, more than two pressed battery cell stacks 3 can also be produced in one working step. For example, four, six or eight pressed battery cell stacks 3 can be produced in one operation, which can form a battery module 1 for a high-voltage battery.As can be further seen from FIGS. 2 to 4, the loose battery cell stacks 2 and the pressed battery cell stacks 3 are separated from one another by plates 9. As can be further seen from FIGS. 2 and 3, eleven battery cells 4 and ten cell separating elements 5 arranged between the battery cells 4 each form a first loose battery cell stack 2A shown on the left and a second loose battery cell stack 2B shown on the right, which are arranged between two press rams 13 of the pressing device 12 and are pressed to form the two pressed battery cell stacks 3 shown in FIG. 4. Here, the first loose battery cell stack 2A is crimped to a first crimped battery cell stack 3A, and the second loose battery cell stack 2B is crimped to the second crimped battery cell stack 3B. The respective ten cell separating elements 5 of the two loose battery cell stacks 2 are each supported by ten support elements 16 of the support device 14.As can be further seen from FIGS. 2 and 3, a first end plate 9A is arranged between a first pressing punch 13A, shown on the left, and a first battery cell 4 of the first loose battery cell stack 2A. A second end plate 9B is arranged between a second pressing punch 13B shown on the right and an eleventh battery cell 4 of the second loose battery cell stack 2B. In addition, a middle plate 9C is arranged between an eleventh battery cell 4 of the first loose battery cell stack 2A and a first battery cell 4 of the second loose battery cell stack 2B.As can be further seen from FIG. 4, in the illustrated exemplary embodiment of the device 10, during the pressing operation, the second pressing ram 13B is moved in the arrow direction towards the first pressing ram 13A. The support elements 16 of the support device 14 are individually pushed along by the pressing process. In the exemplary embodiment shown, the battery module 1 comprises the two pressed battery cell stacks 3A, 3B, which are arranged between the two end plates 13A, 13B and are separated by the central plate 9C.LIST OF REFERENCE CHARACTERS1 Battery module 2, 2A, 2B Loose battery cell stack 3, 3A, 3B Pressed battery cell stack 4 Prismatic battery cell 5 Cell separating element 7 Intermediate space 9 Plate 9A, 9B End plate 9C Central plate 10 Device for producing a pressed battery cell stack 11 Support 11.1 Contact surface 12 Pressing device 13 Pressing plunger 14, 14A, 14B Support device 15 Sliding device 15.1 Slide rail 16 Support element 16A Intrinsically elastic support element 16B Spring-loaded support element 17 Support surface 18 Return connector 19 Adjustable distance dimension A, AP distance 100 Method for producing a pressed battery cell stack S 100 to S 140 Method step

Claims

Method (100) for producing a pressed battery cell stack (3) which comprises a plurality of prismatic battery cells (4) and cell separating elements (5) arranged therebetween, wherein a plurality of prismatic battery cells (4) are provided and are arranged along an axis with an axial intermediate space (7) between the battery cells (4) on a supporting surface (11.1) of a support (11), wherein below the axial intermediate spaces (7) between the battery cells (4) in each case a height-adjustable supporting element (16) for a corresponding cell separating element (5) is arranged, wherein in each case a cell separating element (5) is inserted in the intermediate spaces (7) between the battery cells (4) until it rests on a supporting surface (17) of the corresponding supporting element (16) in such a way that a loose battery cell stack (2) is produced, which is subsequently pressed to form a pressed battery cell stack (3), wherein the support elements (16) for the cell separation elements (5) are designed such that during the pressing process the support surface (17) for the cell separation elements (5) resting thereon is reduced with low force.Method (100) according to claim 1, characterised in that a distance dimension (19) between the support surface (17) of the support elements (16) and the support surface (11.1) of the support (11) is set via the height-adjustable support elements (16).Method (100) according to Claim 1 or 2, characterized in that the supporting surfaces (17) of the individual supporting elements (16) are enlarged again after removal of the pressed battery cell stack (3).Method (100) according to one of Claims 1 to 3, characterized in that a plurality of pressed battery cell stacks (3) are produced in one operation.Method (100) according to claim 4, characterised in that the battery cell stacks (3) are separated from one another by plates (9).Device (10) for producing a pressed battery cell stack (3), which comprises a support (11) with a contact surface (11.1), a pressing device (12) and a supporting device (14) with a plurality of supporting elements (16) and is designed to carry out the method (100) according to one of Claims 1 to 5, wherein the supporting elements (16) for the cell separating elements (5) are designed such that during the pressing process the supporting surface (17) for the cell separating elements (5) lying on it is reduced with low force.Device (10) according to claim 6, characterised in that the support device (14) comprises a sliding device (15) with at least one slide rail (15.1), in which the support elements (16) are mounted so as to be slidable.Device (10) according to claim 6 or 7, characterised in that the support elements (16) are designed as elastic support elements (16A), the effective support surface (17) of which can be changed by elastic deformation.Device (10) according to claim 6 or 7, characterised in that the support elements (16) are designed as spring-loaded support elements (16B), the effective support surface (17) of which can be changed by a rotation.Device (10) according to one of Claims 6 to 9, characterized in that the pressing device (12) comprises two pressing rams (13), between which a plurality of prismatic battery cells (4) and cell separating elements (5) arranged therebetween can be arranged.

Images