DE102016200496B4 - Method and plant for producing a cell module - Google Patents

Abstract

Method for producing a cell module (25), in particular for an electric or hybrid vehicle, in which a stack (21) of storage cells (23) is wrapped by means of a band (24), in particular a fiber-reinforced plastic band, characterized in that Memory cells (23) of the stack (21) in a clamping unit (10) are braced against each other, - the tensioned stack (21) of a gripper (30) gripped and a banding device (44) is fed, - the tensioned stack (21) and the banding device (44) is automatically guided relative to one another in such a way that the band (24) is wound around the tensioned stack (21) and keeps the stack (21) in the tensioned state after the banding, - then the tensioning unit (10) is loosened and the stack (21) is released.

Description

The invention relates to a method and a system for producing a cell module, in particular for an electric or hybrid vehicle, wherein in this case a stack of memory cells is wrapped by means of a tape.

From the DE 10 2014 204 737 A1 Such a stack of storage cells wrapped in a fiber-reinforced plastic band for a high-voltage accumulator of a motor vehicle can be taken from such a stack.

The wrapping of the stack serves to clamp the stack in order to keep the individual storage cells compact in a defined position relative to one another and to avoid expansion of the stack as a result of, for example, discharging and charging cycles during operation.

Traditionally, the stacks were welded into a metal frame. By using a fiber reinforced tape according to the DE 10 2014 204 737 A1 On the one hand the advantage of a weight saving compared to conventional metal tenter is achieved. On the other hand, the banding makes it easier to adapt to different stack sizes.

The memory cells of interest in the present case are, in particular, lithium-ion memory cells, especially prismatic memory cells, which are combined overall to form a cuboid stack for forming the cell module. Several such cell modules are usually arranged in a memory unit for forming a high-voltage memory especially for use in a motor vehicle.

Proceeding from this, the object of the invention is to enable a cost-effective and efficient production of such cell modules.

The object is achieved according to the invention by a method for producing a cell module having the features of claim 1 and by a system having the features of claim 16.

The advantages and preferred embodiment cited with regard to the method are to be transferred analogously to the system. In this case, to form a cell module, a stack of memory cells, in particular lithium-ion memory cells, is wrapped with the aid of a band, in particular a plastic band, especially a fiber-reinforced plastic band. The plastic of the band is preferably a thermoplastic. Alternatively, a particular fiber-reinforced adhesive tape can be used, as in the DE 2014 204 737 A1 is described. In order to enable an automated winding, hereinafter also referred to as banding, the memory cells of the stack are first braced against each other in a clamping unit. Finally, the tensioned stack is gripped together with the clamping unit by a gripper and fed to a banding device. Finally, the tensioned stack and the banding device are guided relative to each other and automated so that the belt is automatically wrapped around the tensioned stack, so that the stack is held in tension by the belt after banding. Finally, after the banding the clamping unit is released again and the stack is released for subsequent confectioning steps. In particular, a plurality of such stacks or cell modules are assembled in a memory unit for forming a high-voltage accumulator for a motor vehicle. The gripping of the taut stack, the banding and the subsequent release of the banded stack are carried out in particular fully automatically without manual intervention.

The described process sequence with the clamping of the memory cells in a clamping unit and the subsequent gripping and feeding to the banding device together with the clamping unit located on the stack enable a simple automated production. By the clamping unit namely - regardless of the gripper - the stack of memory cells in the tensioned state held reliable until the required clamping force is absorbed by the tape.

As a result, a process-reliable automated and reliable banding of the stack is achieved overall. It is furthermore of particular advantage that the method and also the system are suitable for different module sizes of the cell module without special adaptations, ie that no different system components are required for different module sizes. Overall, a cost-effective and efficient manufacturing process is thus achieved for mass production.

For clamping the stack in the clamping unit, the system further expediently has a pretensioning device. The clamping unit also comprises a clamping element, in particular a spring element. About this clamping element, the clamping force is exerted on the stack. Within the biasing device now the clamping element is biased, then the stack is inserted and clamped. Finally, the clamping unit with the stack clamped therein is removed from the pretensioner by means of the gripper. About the clamping element is therefore the Stack stretched during the Bandierungsvorgangs by the preferably passive acting spring force of the clamping element. By the biasing means, which is generally designed for biasing the at least one clamping element and in this case in particular pulls jaws of the clamping unit apart, the insertion of the unstretched cell stack or of the individual memory cells is initially made possible. Also, this sub-process is therefore automatically implemented in a simple manner and preferably takes place without manual interaction.

In order to reliably ensure automated pretensioning, the pretensioning device, in an expedient embodiment, has a pretensioning unit with a gripping element. This preferably grips the clamping element for the purpose of biasing automatically when inserting the clamping unit in the biasing device. The clamping element has a corresponding gripping element. In a preferred embodiment variant, the gripper element pair is a receptacle, in particular a ring eyelet, as well as an engagement element, in particular a bolt, pin or a claw. Specifically, the gripping element pair is designed for mutual positive engagement. By the biasing unit, the clamping element is transferred to a tensioned state.

In the automated process sequence, the clamping unit is therefore stored at a defined position within the pretensioner. For this purpose, the biasing device in particular a holder, which is formed for example as a shelf (plate).

After banding the wrapped with the tape stack is brought back into the biasing device and released there in particular automated.

This is done in a similar manner as the automated biasing of the clamping element and clamping the stack: Using the mutually corresponding gripping elements of the biasing unit and the clamping element, the clamping element is again (up) stretched, whereby the stack is released.

Conveniently, a pressure plate is further arranged on at least one end side and preferably on both opposite (end) end sides of the stack. This is further preferably each pressed using a jaw of the clamping unit against the stack. As a result, the clamping and pressing forces exerted by the clamping unit are transmitted to the stack as uniformly as possible and over the entire surface over the opposite end faces. The necessary jaws of the clamping unit protrude here only over a limited height of the stack, so as not to interfere with the subsequent banding process. The jaws overlap, for example, the stack only a maximum of up to a third and preferably a maximum of up to a quarter of its height.

In a preferred development, the pressure plate on the edge-side elevations for receiving fasteners for subsequent assembly of the cell module. Between two opposite such elevations, the tape is passed. The two surveys therefore define a gap in the manner of a groove for the band. The tape is therefore performed on a transverse side of the printing plate between two surveys.

In addition, it is provided in a preferred embodiment that the pressure plate in total at its four corners in each case has a survey and that engages between two longitudinally spaced elevations a jaw of the clamping unit.

The pressure plate itself is preferably arranged without fasteners such as screws, clamps, etc. adjacent to the stack. In the region of the band, the printing plate preferably defines an uninterrupted surface.

Furthermore, the pressure plate is expediently made of plastic, in particular of a thermoplastic plastic and especially of polyamide. By this choice of material in particular a good first-layer fixation of the (plastic) tape, in particular by welding, ensures, which is e.g. in the use of metal or thermosetting plastics in general is not possible.

In order to avoid damage to the band in the edge region, the printing plate has rounded edges on the edge.

The printing plate is fixed before the beginning of the banding, on the front side of the stack, in particular glued, for example by an adhesive film or other adhesive.

With regard to automated banding, the gripper is preferably attached to a robot hand of an industrial robot. The industrial robot is generally a Gelenkarmmechanismus, with the help of the gripper and thus the stack can be moved freely in space. In particular, it is an at least six-axis industrial robot. The robot hand is usually supported by a joint about several axes rotatably mounted on a robot arm. In principle, wrapping is also possible with only one axis around which the gripper is rotated.

Due to the free controllability of such industrial robots, the clamping unit with the stack clamped therein is guided past the stationary banding device by suitable movement operations during the banding in an expedient development. These movement operations include in particular rotational movements, but also translational movements. By the movement of the stack, the tape is preferably automatically withdrawn from the banding device. So there is no additional drive for the band required.

In particular, at the beginning of the Bandierungsvorgangs the band is fixed to the stack by a fixing operation in a preferred embodiment. This is done in particular by welding the tape to the stack and in particular to one of the printing plates. In particular, by the design of the band as (fiber-reinforced) plastic tape and the design of the pressure plate made of plastic welding these elements together by simple heating is possible in which at least one and preferably both of these parts are melted at least on its surface. Overall, a cohesive connection between the band and the pressure plate is formed by the welding. As an alternative to welding, the tape can also be glued or clamped.

Conveniently, no further fixing operations of the tape are provided on the stack. The band is therefore attached to the stack exclusively by the fixing process, preferably by welding.

In an expedient development, the band is further preheated prior to banding and in particular continuously during the entire banding process and, in particular, melted at least on its surface. By this measure, the surface of the tape is generally sticky so that they not only welded to the pressure plate but also, for example, assumes an adhesion to lying between the printing plates side portions. Continuous heating also has the advantage that, in the case of multi-layer banding, a fixation takes place between successive layers, in particular a welding, that is to say a cohesive connection.

Alternatively, preheating is dispensed with. In particular, the tape is not melted. Furthermore, the various layers are not necessarily merged with the printing plates (possibly up to a Erstlagenfixierung at least on one of the printing plates) and / or with each other. In comparison with preheating, in this case e.g. higher process speeds can be achieved.

To ensure this in a simple manner, the banding device has a heating zone, which is subsequently arranged to form a unwinding unit for the band. The band continuously passes through the heating zone during banding, so that the band is preheated therein and in particular fused.

Furthermore, the banding device is characterized in an expedient embodiment by a brake unit for the band. By pulling off the tape from the unwinding unit in combination with the brake unit, the tape is thereby pre-tensioned, so that overall the stack is tensioned with a high clamping force.

The brake unit in this case has at least two rollers between which the belt extends, wherein one of the rollers is braked.

Furthermore, the banding device comprises a pressure roller, with the aid of which the band is pressed against the stack during the banding. As a result, a reliable system of the tape is guaranteed at the stack.

• 1 eine Seitenansicht einer Vorspanneinrichtung mit Spanneinheit und darin einliegendem Stapel,
• 2 eine perspektivische Aufsicht auf die Vorspanneinrichtung mit darin angeordneter Spanneinheit,
• 3 eine Draufsicht auf die Unterseite der Spanneinheit,
• 4A,4B Seitenansichten einer Druckplatte,
• 5 eine Schnittansicht durch einen Greifer,
• 6A eine ausschnittsweise vereinfachte Darstellung einer Anlage zur Durchführung des Verfahrens mit einem Industrieroboter, einem Greifer mit daran gehaltener Spanneinheit und einer Bandierungsvorrichtung in einer perspektivischen Darstellung,
• 6B die Anlage gemäß 6A in einer Seitenansicht,
• 7 eine Schnittdarstellung einer Bremseinheit für das Band.

An embodiment of the invention will be explained in more detail with reference to FIGS. These show in partially simplified representations:

• 1 a side view of a pretensioner with clamping unit and stack therein,
• 2 a perspective view of the biasing device with therein arranged clamping unit,
• 3 a plan view of the underside of the clamping unit,
• 4A . 4B Side views of a printing plate,
• 5 a sectional view through a gripper,
• 6A 1 a fragmentary simplified representation of a system for carrying out the method with an industrial robot, a gripper with a clamping unit held thereon and a banding device in a perspective view,
• 6B the system according to 6A in a side view,
• 7 a sectional view of a brake unit for the band.

In the figures, the same parts with the same reference numerals.

The in the 1 and 2 shown biasing device 2 has a base plate 4 on, on a bias unit 6 and in the embodiment designed as supporting posts holder 8th are arranged. On the holders 8th is a clamping unit 10 stored. In the exemplary embodiment, the holders are designed such that they with respect to the base plate 4 are inclined.

The clamping unit 10 has a mounting plate 12 on, at the bottom in the embodiment, two clamping elements designed as gas springs, in particular gas tension springs 14 are arranged. These are with their one end to the mounting plate 12 fixed and its other end is connected to a first jaw 16A, which is relative to the mounting plate 12 is displaceable. It is on this telescopic extension elements, for example, in the mounting plate 12 recessed guide rods, slidably mounted. Opposite the first jaw 16A indicates the clamping unit 10 a second jaw 16B on. At the first jaw 16A Further gripping elements are arranged, which in the embodiment as eyelets 18 are formed.

Corresponding to this, the biasing unit 6 also a gripping element 20 on which bolts included in the eyelets 18 intervention. The gripping element 20 is on clamping piston of the pretensioning unit 6 arranged. About the preload unit 6 is a clamping force, in particular tensile force, on the clamping elements 14 exercised, so that they are biased. Here are the two jaws 16A 16B slightly apart. At the bias unit 6 it is in particular a pneumatic unit, so so so the clamping elements 14 be pneumatically biased.

In the 1 is still a stack already 21 with a plurality of individual prismatic memory cells 23 illustrated. Both ends of the stack each have a printing plate 22 on, between which ultimately the memory cells 23 be clamped. The whole pile 21 is - as described in more detail below - wrapped by a tape 24 and in the tensioned state on this band 24 held. This is a particular fiber-reinforced plastic tape. This is in 1 shown in dashed lines. The wrapped with the tape 24 stack 21 forms a cell module 25 ,

At the pressure plate 22 in particular, it is a plastic pressure plate, which at the four corners elevations 26 has the nature of webs. In these surveys 26 In particular, bores are introduced, in which then screws for fixing the stack in a storage unit (high-voltage storage) are introduced. In general, the assembly of the cell module in the storage unit takes place via the pressure plates 22.

The 4A shows a side view on a transverse side of the printing plate. Between the two opposite elevations 26wird the tape 24 passed.

4B shows a side view on a longitudinal side of the printing plate 22 , Between the two opposite elevations 26 on the long side grab the two jaws 16A . 16B one.

Furthermore, in 5 a sectional view of a gripper 30 represented by means of which the stack 21 opposite to the clamping unit 10 in the upper of the in 1 area is seized.

The gripper 30 also has two opposite jaws 32A , 32B, in turn, one of the two jaws 32A in particular by means of a pneumatic unit 34 can be moved against the opposite fixed jaw 32B. The displaceable clamping jaw 32A is in this case in particular on a guide rail 36 a linear guide of the gripper 30 guided. At the top, the gripper points 30 continue a mounting plate 38 for attachment to a robot hand 40 ( 6B ) of an industrial robot 42 on.

A plant 43 for automated banding according to the 6A . 6B has the industrial robot 42 , the gripper 30 , the tensioning unit held by it 10 which (in the 6A . 6B not shown) biasing device 2 and further a banding device 44 on. This has an unwinding unit 46 , a heating zone 48 and a pressure roller mounted on an arm 50 on. The unwinding unit 46 also has an in 7 sectional brake unit 52 on. The brake unit 52 serves to bias the tape 24 , For this purpose, the brake unit comprises 52 a leadership role 54 as well as two rollers 56 , The ribbon 24 is between each leadership role 54 and passed through one of the rollers. The two rollers 56 are against the leadership role 54 pressed, preferably by means of damper elements 58 , The rollers 56 are therefore fastened by a variable suspension, which results in a total of one on the band 24 applied biasing force can be varied. The set preload force for pretensioning the band 24 is preferably in the range between 10 to 20 N.

The method for automated banding of the stack 21 is as follows: In a first step, the individual memory cells 23 together with the printing plates 22 in the clamping unit 10 inserted ( 1 ). To do this, first use the preload unit 6 the clamping elements 14 biased. The two jaws 16A . 16B are therefore in the open state, so that the individual memory cells 23 and the printing plates 22 can be easily inserted. The loading of the clamping unit 10 with memory cells 23 and the printing plates 22 is preferably also done in a manner not shown here automated without manual interaction.

Subsequently, the connection between the gripping element 20 and eyelets 18 solved so that by the prestressed clamping elements 14 the stack 21 in the clamping unit 10 between the jaws 16A . 16B is clamped.

In the next step, the gripper moves 30 using the industrial robot 42 to the pretensioner 2 and the stack 21 is with the jaws 32A , 32B of the gripper 30 opposite the clamping unit 10 resorted. Then the stack 21 together with the clamping unit 10 from the pretensioner 2 taken out and to the banding device 44 guided.

Subsequently, in a first step, an end piece of the tape 24 on one of the two printing plates 22 fixed. This is the tape 24 and in particular also the printing plate 22 heated so that each of the plastic melts something. The ribbon 24 is against the surface of the printing plate 22 pressed, so that a cohesive (welding) connection is formed.

Below is the stack 21 using the gripper 30 on the fixed banding device 44 suitably guided along, so that the tape successively around the circumference of the stack 21 is handled around. The stack 21 This is from the gripper 30 in particular also rotated and on the (fixed) pressure roller 50 guided along with its peripheral side.

The ribbon 24 goes through the heating zone continuously 48 in which at least the surface of the tape 24 is melted. The ribbon 24 is preferably in several layers around the stack 21 wound. The banding process becomes the band 24 using the pressure roller 50 against the pile 21 pressed. Within the heating zone 48 the strip is heated in total to a temperature above 200 ° C, in particular to a temperature in the range between 240 ° and 300 ° C. The heating zone 48 is formed in particular in the manner of a furnace.

To provide sufficient tension for the band 24 to get through this before entering the warming zone 48 still in the 7 illustrated brake unit 52 ,

After the end of the tape process, the tape becomes 24 initially separated. Then the gripper moves 30 with the banded stack 21 again to the pretensioner 2 back, put there the clamping unit 10 with the banded stack 21 from. Preferably in particular such that when depositing automatically the gripping elements 20 in the eyelets 18 intervention. Using the bias unit 6 then become the clamping elements 14 cocked again, so the banded stack 21 is released. Then this is from the clamping unit 10 in turn, in turn, automatically taken, for example, using a second robot.

Through the system described here 43 Overall, a process-reliable automated banding of a stack 21 allows. At the same time, due to the special design of the components selected here, the entire system can be used universally for different stack sizes, ie the system can be easily scaled for different stack sizes.

By using a fiber-reinforced plastic band 24 in combination with the plastic printing plates 22 is - in contrast to the use of conventional metal frame - initially achieved a significant weight savings. In addition, with the structure selected here, a banding with a high band bias voltage is ensured, so that changes in position of the individual memory cells during operation 23 at least largely avoided.

The high system flexibility for the treatment of cell modules of different sizes is particularly due to the selected robot technology with suitable robot control and the flexible gripping technology on the one hand, the clamping unit 10 and on the other hand also the gripper 30 achieved.

LIST OF REFERENCE NUMBERS

2

biasing means

4

baseplate

6

biasing unit

8th

holder

10

clamping unit

12

mounting plate

14

clamping elements

16A

first jaw

16B

second jaw

18

eyelet

20

gripping element

21

stack

22

printing plate

23

memory cells

24

tape

25

cell module

26

survey

30

grab

32A, B

jaws

34

pneumatic unit

36

guide rail

38

mounting plate

40

robotic hand

42

industrial robots

43

investment

44

Bandierungsvorrichtung

46

unwinding

48

heating zone

50

pressure roller

52

brake unit

54

leadership

56

caster

58

damping element

Claims (16)

Method for producing a cell module (25), in particular for an electric or hybrid vehicle, in which a stack (21) of storage cells (23) is wrapped by means of a band (24), in particular a fiber-reinforced plastic band, characterized in that - Memory cells (23) of the stack (21) in a clamping unit (10) are braced against each other, - the tensioned stack (21) of a gripper (30) gripped and a banding device (44) is fed, - the tensioned stack (21) and the banding device (44) is automatically guided relative to one another in such a way that the band (24) is wound around the tensioned stack (21) and keeps the stack (21) in the tensioned state after the banding, - then the tensioning unit (10) is loosened and the stack (21) is released. Method according to Claim 1 , characterized in that the clamping unit (10) comprises a clamping element (14) for exerting the clamping force on the stack (21), wherein the clamping element (14) in a biasing means (2) is biased, the stack (21) inserted and clamped and then the clamping unit (10) with the stack (21) clamped therein is taken out of the pretensioning device (2) by means of the gripper (30). Method according to Claim 2 , characterized in that the biasing means (2) for automatically biasing the clamping element (14) comprises a biasing unit (6) with a gripping element (20), which preferably when inserting the clamping unit (10) in the biasing means (2), the clamping element (14 ) automatically attacks. Method according to Claim 2 or 3 , characterized in that after the banding, the clamping unit (10) is brought back into the biasing means (2) for automated release of the stack (21). Method according to one of the preceding claims, characterized in that at least on one end side of the stack (21) a pressure plate (22) is arranged, which by means of a jaw (16A, 16B) of the clamping unit (10) against the stack (21) is pressed , Method according to Claim 5 , characterized in that the pressure plate (22) edge-side elevations (26) and the band (24) between two elevations (26) is laid. Method according to Claim 6 , characterized in that the clamping jaw (16A, 16B) between two elevations (26) engages. Method according to one of Claims 5 to 7 , characterized in that the pressure plate (22) consists of plastic. Method according to one of the preceding claims, characterized in that the gripper (30) on a robot hand (40) of an industrial robot (42) is attached. Method according to one of the preceding claims, characterized in that the banding device (44) is arranged stationary and the clamping unit (10) is rotated with the clamped therein stack (21) for banding by means of the gripper (30). Method according to one of Claims 5 to 8th , characterized in that the band (24) at the beginning of the banding with the pressure plate (22) is welded. Method according to one of the preceding claims, characterized in that the band (24) is melted before banding. Method according to one of the preceding claims, characterized in that the banding device (44) has an unwinding unit (46) for the band (24) and subsequently a heating zone (48) and the band (24) is continuously passed through the heating zone (48) during banding ) running. Method according to one of the preceding claims, characterized in that the banding device (44) has a braking unit (52) for the band (24), so that the band (24) is biased by striping from the banding device (44) during banding. Method according to one of the preceding claims, characterized in that the banding device (44) has a pressure roller (50) by means of which the band (24) is pressed against the stack (21) during the banding. Plant (43) for producing a cell module (25), in particular for a method according to one of the preceding claims, which is designed for automated wrapping of a stack (21) of memory cells (23) with a band (24), and comprises: - A clamping unit (10) in which the memory cells (23) of the stack (21) are braced against each other, a banding device (44) for wrapping the stack (21) with a band (24), - A gripper (30) for gripping the in the clamping unit (10) tensioned stack (21) and for supplying the same to the banding device (44), wherein the gripper (30) and the banding device (44) relative to each other so automated feasible, that the tape (24) is wound around the tensioned stack (21).

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