DE102012212887A1 - Accumulator with galvanic cells - Google Patents

Abstract

The invention relates to an accumulator (10) with at least one galvanic cell (12), which comprises a film envelope (16) extending in a plane and designed as a flat body with a narrow side with a narrow side and a flat body has circumferential and extended in the plane of a flat body edge portion (22). The edge part (20) has a sealing seam (18) sealing the film envelope (16), through which a first connection electrode (22) and a second connection electrode (24) of the galvanic element (13), which is electrically separate from the first connection electrode (22) the film (16) is guided. The edge part (20) is at least partially embedded in a holding structure (40, 48, 50) of adhesive material covering the sealing seam (18).

Description

The invention relates to an accumulator having at least one fixed to a support, galvanic cell having a one in a plane extending, designed as a flat body designed with a narrow side galvanic element film envelope with a circulating on the narrow side of the flat body and in the plane of the flat body has extensive edge portion which has a sealing foil sealing seam, through which a first connection electrode and a second connection electrode of the galvanic element separated from the first connection electrode are guided out of the film envelope.

Such accumulators are z. B. used in the form of lithium-ion batteries as electrical energy storage. Accumulators according to the invention can be used in stationary and transient systems. As transient systems come z. B. all types of (land) vehicles, ships and aircraft into consideration. Accordingly, the invention also relates to such applications. Lithium-ion batteries usually contain up to 100 or even more galvanic elements which are arranged in a bag-shaped film casing and have an electrolyte in which lithium ions are displaced. With the bag-shaped film envelopes so-called bag cells or "pouch cells" are formed. The bag-shaped foil sheaths are produced by welding together flat foil lying on each other. The service life of lithium-ion batteries is significantly influenced by the tightness properties of the respective bag cells. During the operation of a vehicle, such bag cells are subject to vibrations and thus to mechanical stresses which can lead to leaks in a bag cell.

The object of the invention is to provide an accumulator with a long service life, in which at comparatively low weight electrical energy can be stored with a high energy density and which is particularly suitable for use as energy storage in a mobile application.

In addition, it is an object of the invention to provide a method for producing a rechargeable battery, which can be easily adapted to the dimensions of the galvanic cells in the accumulator and the space provided for the accumulator.

This object is achieved by an accumulator having the features of claim 1 and a method having the features of claim 12. Advantageous embodiments of the invention are indicated in the dependent claims.

In the accumulator according to the invention, the peripheral edge part is at least partially embedded in a holding structure of adhesive material covering the sealing seam.

The invention is based on the idea that adhesives which are suitable for the mechanical joining of assemblies can also fulfill a sealing function. One idea of the inventor is therefore to additionally seal the sealing or sealing seams (sealing or sealing beads) which are so decisive for the life of a rechargeable battery of galvanic cells, also referred to as bag cells, by embedding them in beads of adhesive material and thus additionally sealing them be that the gas exchange is avoided at the peripheral edge of a bag cell. The beads of adhesive material form a support structure / support structure. This structure is arranged between a base plate and an end plate. The use of the adhesive material has the advantage that the adhesive material on the one hand has a sealing function and on the other can damp vibrations. If, for example, the accumulator is used in a motor vehicle, then vibrations of the vehicle are transmitted to the accumulator. These vibrations can cause leaks in the foil sheaths. In the accumulator according to the invention, these oscillations are damped by means of the holding structure consisting of adhesive material.

Preferably, an elastomer is used as the adhesive material. An elastomer is a dimensionally stable, but elastically deformable plastic. Elastomers can thus be deformed so that they find their way back to their original, undeformed shape after deformation.

The elastomer is applied in a (highly) viscous state and subsequently cured, whereby the molding strength increases and elastic deformability is achieved. Depending on the method, the application viscosity is between 10 ² and 10 ¹⁰ mPa · s (milliPascal seconds), preferably between 10 ³ and 10 ⁴ mPa · s. As elastomers are mainly non-Newtonian liquids with a pronounced thixotropy (intrinsic viscosity). To apply the sealing seam under shear stress is a lowering of the dynamic viscosity, which facilitates the application, ie the application significantly. After application, the viscosity increases to values above the yield point, with the result that the applied sealing seam no longer changes its shape, ie no longer flows. The elastomer may be a silicone material, in particular a silicone rubber or an epoxy resin. In particular, can be provided as a deformable plastic, a polyester resin or other plastic, which can be cured with UV light. The hardness to be achieved after curing depends in particular on the particular application, so that elastomeric plastics with comparatively high hardness can be used.

Before curing, the elastomer can also be injected into any shape. First, it is not yet elastic, i. the elastomer does not yet return to its original shape. Thus, simply by spraying the viscous elastomer, any holding structure of adhesive material can be produced which remains dimensionally stable after curing, drying, cooling and / or reacting.

Preferably, the elastomeric material for an accumulator is applied with the laying of beads by means of shaping dies.

The adhesive material for the support structure in an accumulator according to the invention can also be applied in the so-called airless spray process. In this process, under high pressure (about 200 bar), the highly viscous material is applied in small drops in a sharply limited form. Another possibility for applying adhesive material is printing in an inkjet process.

Depending on the application, the following plastics are suitable as adhesive material for the support structure in an accumulator according to the invention:
Acrylonitrile butadiene acrylate, acrylonitrile methyl methacrylate, butadiene rubbers, butyl rubbers, ethylene-ethyl acrylate copolymers, ethylene-propylene copolymers, ethylene-propylene-diene rubbers, ethylene vinyl acetates, fluororubbers, isoprene rubbers, polyisobutylenes, polyurethanes, styrene Butadiene rubbers, styrene-butadiene-styrenes, vinyl chloride / ethylene and the like. In particularly preferred embodiments, natural rubber or silicone rubber is used. They are characterized by good processing and resistance properties. Also suitable are silanes, polyvinyl chloride (PVC plastisols), polyurethane (1K-PUR, 2K-PUR), PMMA plastisols (polymethyl metharrylate) and epoxy resins. To quickly reach a viscosity above the yield point, 2-component systems or moisture-curing systems are particularly suitable, wherein the relative humidity can be increased artificially and / or temporarily for rapid curing.

Preferably, the adhesive material consists of materials which harden quickly on their own, so that no curing process is required before the next stacking operation (insertion of the galvanic cell, application of the next sealing seam bead). Should intermediate curing be necessary, however, short-term heat input or modified atmosphere composition processes (eg, increasing relative humidity) would be the preferred choice.

Especially in the area of connection electrodes, which protrude from the film envelope, there is a great risk of leaks. In particular, a penetration of moisture is to prevent. Conventionally, this has been taken into account by the connecting seams, in particular in the region of the terminal electrodes have been made particularly large or wide. Due to the invention, it is now possible to make the sealing seams of the film envelope, which are generally designed as welds, comparatively narrow. This has the advantage that accumulators according to the invention build smaller and thus in the overall view have an increased energy density. The required tightness is ensured by the embedding in the adhesive material of the beads.

In particular, it has proven to be advantageous for the region in which the connection electrodes protrude from the film envelope to be embedded in the adhesive material.

In order to increase the tightness of the galvanic cell, it has also proven to be advantageous that the peripheral connection seam of the galvanic cell is completely surrounded by adhesive material. The connecting seam represents the edge of the galvanic cell.

The inventive method for producing a rechargeable battery comprises the construction of a battery stack with galvanic cells arranged on one another. The battery stack of galvanic cells is made by means of adhesive beads. In this case, the galvanic cells are additionally sealed in a single operation by the beads of adhesive material and glued into a stack. This allows sealing and mechanical stabilization of a battery stack in one and the same operation. With the method according to the invention it is therefore possible to produce batteries cost.

In addition, it is also possible to give the battery stack in an accumulator a basically arbitrary shape. Consequently, the method for manufacturing a rechargeable battery can be adapted very easily to different forms of battery bags by adapting the structure of the applied adhesive material to the shape of the battery bags, so that again the connecting seams of the battery bags used in FIG Adhesive material to be embedded. Thus, it is possible with little effort to adapt the dimensions of batteries to the various installation situations that arise in different applications. The low cost results in particular in that no special, adapted to the bag shape tool is required.

In the following the invention will be explained in more detail with reference to the embodiments schematically illustrated in the drawing.

Show it:

1 an accumulator containing a plurality of galvanic cells;

2 to 4 the galvanic cells and the structure of the accumulator;

5 a cut of the one in the 4 shown accumulator assembly along the sectional area AA;

6 a made with the reference numeral VI indicated enlarged section 5 with an electrode region of the galvanic cells of the accumulator;

7 a portion of an accumulator having a holding structure of adhesive material in which cooling channels are formed;

8th a portion of another accumulator having a holding structure of adhesive material and cooling channels;

9 and 10 a plant for the production of accumulators.

The Indian 1 shown accumulator 10 has a base plate 28 and an end plate 30 , which preferably consists of a lightweight material, such as die-cast aluminum, but which may also consist of a particular thermoset plastic material. The base plate 28 and the end plate 30 have a Standardungsbemaßung and have a design that z. B. is designed for the installation of the accumulator in the bottom pan of a motor vehicle.

The accumulator 10 has an accumulator wall made of beads of adhesive material 52 holding a stack of eight galvanic cells 12 surrounds, each connecting electrodes 22 . 24 exhibit. The connection electrodes 22 . 24 the galvanic cells 12 enforce the accumulator wall 52 , The accumulator wall 52 is made by superimposing caterpillars of adhesive material, eg approx. 10 mm wide and 15 mm are high. Such caterpillars of adhesive material are used in motor vehicle technology, for example for the bonding of windscreens in motor vehicle bodies use. The accumulator wall 52 acts for the galvanic cells 12 as a holding structure. It is thus also possible to use an accumulator according to the invention with more than eight galvanic cells 12 train. Alternatively, a large battery of several small modules according to the invention is assembled (and possibly housed in a common housing.

For stabilizing the stack of galvanic cells 12 are the base plate 28 and the end plate 30 through fastening straps 32 connected.

The 2 to 6 show the galvanic cells 12 and explain the structure of the accumulator 10 , The galvanic cells 12 of the accumulator 10 are designed as a so-called pouch cell or coffee bag cell. The galvanic cells contain a galvanic element 13 in the form of a lithium-ion battery.

The galvanic element 13 is an in-plane cuboidal flat body consisting of a plurality of thin coated copper or aluminum metal foils, each separated by an ion-permeable, electrolyte-impregnated separator to form a sandwich structure. The sandwich structure with the electrolyte-soaked separator is in a foil wrapper 16 arranged from a fluid-tight plastic-aluminum composite material. The foil cover 16 is from a first slide 15 and a second foil 17 together. The foil cover 16 has one in the plane of the galvanic element 13 extended edge part 20 that is a sealing seam 18 having. With the sealing seam 18 becomes the foil cover 16 sealed. Through the sealing seam 18 are the connection electrodes 22 . 24 the galvanic cell 12 guided. The edge part 20 the foil cover 16 surrounds the galvanic element.

The connection electrodes 22 , 24 are spaced from each other. In the illustrated embodiment, the first 22 and the second terminal electrode 24 on one and the same side of the galvanic cell 12 positioned. But it is also possible in principle that the connection electrodes 22 . 24 on different sides of the galvanic cell 12 protrude.

It should also be noted that the galvanic element 13 does not necessarily have to be designed as a cuboid flat body. The galvanic element can basically also be designed as a flat body with an arbitrary base area.

The edge part 20 the foil cover 16 is in the accumulator wall 52 embedded. The support structure of the accumulator wall 52 covers the sealing seam 18 and surrounds the outer contour 21 the edge part 20 ,

The accumulator 10 is manufactured by on the in the 1 shown base plate 28 in the area of its peripheral edge a first caterpillar 40 is applied from a particular elastomeric adhesive material. On the caterpillar 40 adhesive material then becomes a galvanic cell 12 hung up. The on the base plate 28 applied first caterpillar 40 made of adhesive material is dimensioned so that the sealing seam 18 the galvanic cell 12 on the caterpillar 40 lying approximately in the middle.

In a next step, then becomes another caterpillar 48 made of adhesive material on the peripheral edge part 20 the galvanic cell 12 applied. The edge part 20 the galvanic cell 12 gets into the caterpillars 40 . 48 embedded in adhesive material. The two sides of the sealing seam 18 are covered with adhesive material. The outer contour 21 the edge part 20 is there with the adhesive material of the caterpillars 40 . 48 surround.

Following this will be on the caterpillar 48 from adhesive material another galvanic cell 12 put on and then with a caterpillar 50 made of adhesive material with the bead 48 glued from adhesive material, wherein the edge part of the galvanic cell 12 embedded in the adhesive material, the sealing seam 18 covered on both sides with adhesive material and the outer contour 21 the edge part 20 from the adhesive material of the caterpillars 48 . 50 is surrounded.

This process continues accordingly so as to form a stack with a plurality of galvanic cells 12 to accomplish. A galvanic cell 12 in the stack is on each one of caterpillars 40 . 48 . 50 set of adhesive material formed holding structure. The support structure for a galvanic cell 12 has a caterpillar 40 . 48 . 50 made of adhesive material on which the galvanic cell 12 with its peripheral edge part 20 rests and contains a caterpillar 48 . 50 made of adhesive material, on the edge part 20 the relevant galvanic cell 12 is applied. By the successive application of the caterpillars 40 . 48 . 50 becomes the accumulator wall 52 built up. The holding structures made of elastomeric adhesive material with the caterpillars 40 . 48 . 50 cause for the galvanic cells both a support and a sealing function. In addition, the support structures damp vibrations and vibrations that accumulate in the accumulator 10 be initiated when this z. B. is mounted in a motor vehicle. This will be undesirable, life-reducing mechanical shocks of galvanic cells 12 in the accumulator 10 reduced.

By the galvanic cells in the area of the terminal electrodes 22 . 24 in the adhesive material of the caterpillars 40 . 48 . 50 embedded, it is possible to use the galvanic cells 12 here additionally seal. The design of the accumulator according to the invention 10 thus allows diffusion of moisture through the connection seam in the galvanic cell is largely prevented.

If the beads of adhesive material have a height of eg 15 mm and a width of z. B. 10 mm and the galvanic cells 12 are about 10 mm thick, touch the galvanic cells 12 in the accumulator 10 not each other. But if the distance between the galvanic cells 12 here is less than 5 mm, so are the galvanic cells 12 depending on their state of charge pressed together

By means of the caterpillars 40 . 48 . 50 From adhesive material it is also possible to have a different geometrical dimensioning of galvanic cells 12 compensate, such as a different thickness of the material of the film envelope 16 a galvanic cell 12 or a different dimensioning in the foil cover 16 arranged galvanic element 13 ,

It is also possible to measure the surface by means of a camera system and to calculate unevennesses before applying the next following bead application. By appropriate application of the track material or the spray rate can be made with this order a height correction.

At the base plate 28 and the end plate 30 of the accumulator 10 there are fastening straps 32 comprising mechanically connecting the base plate and end plate to means for stabilizing the accumulator 10 enable. It should be noted that an inventive accumulator 10 also by means of the base plate 28 and end plate 30 connected tie rods or straps can be additionally stabilized. Moreover, it is possible to glue an accumulator according to the invention in a stabilizing, in particular cup-shaped container.

The 7 shows a portion of an alternative constructed accumulator 10 ' that has several cooling channels 34 which is in the accumulator wall 52 ' are integrated. Also the cooling channels 34 are with a caterpillar 40 ' made of adhesive material. The cooling channels 34 in the accumulator wall 52 ' are closed. This ensures that one through the cooling channels 34 through-flow cooling medium not with the galvanic cells 12 in contact.

The 8th shows a portion of another alternative accumulator 10 '' one of caterpillars 40 '' . 48 '' constructed accumulator wall 52 '' that with cooling channels 34 ' is trained. The cooling channels 34 ' run here so that the galvanic elements 12 in the accumulator 10 '' can be flowed directly by a cooling fluid. If the galvanic cells 12 in the accumulator 10 ' outgas, here can from a galvanic cell 12 released medium via a cooling channel 34 ' also be dissipated.

As a cooling fluid in the accumulators described above 10 ' . 10 '' is suitable both liquid and gaseous medium.

If a cooling liquid is used as the cooling fluid and a flow restrictor is arranged between an expansion tank, not shown, and the cooling channels, then it can be achieved that the cooling fluid provides further damping against vibrations of the galvanic cells 12 causes. In addition to the shown forms of cooling channels 34 . 34 ' can also be provided instead of cooling channels with a large free diameter and a variety of small cooling channels.

The 9 and 10 show a plant 54 for producing the accumulators described above 10 . 10 ' . 10 '' , The attachment 54 contains robots 56 . 58 and has one around a rotation axis 62 according to the arrow 64 movable turntable 60 , Alternatively, this can be done with any suitable kinematics or positioning technology with freely programmable control. The robot 56 is a gripping system. This will be the base plate first 28 positioned. Then by means of the robot 58 through a nozzle 59 a caterpillar 40 . 40 ' . 40 '' made of adhesive material on the base plate 28 applied and then a galvanic cell 12 with the gripping system or robot 56 on this caterpillar 40 . 40 ' . 40 '' made of adhesive material. After the caterpillar 40 . 40 ' . 40 '' has developed from adhesive material by increasing the viscosity (curing) according to stability, is in another layer the next bead 48 . 48 ' . 48 '' applied and the next galvanic cell 12 is placed. Then another bead is applied as an adhesive material and so on. The final step is then the end plate 30 applied and the corresponding accumulator 10 . 10 ' . 10 '' to finish.

By simply reprogramming the robot 58 it is possible in this manufacturing process, the shape and the course of the beads 40 . 40 ' . 40 '' to any forms of galvanic cells 12 adapt. A complex tool change is not required.

In summary, in particular the following preferred features of a device according to the invention are to be noted: The invention relates to an accumulator 10 with at least one galvanic cell 12 comprising a galvanic element formed in a plane and designed as a flat body with a narrow side 13 surrounding foil cover 16 with a circumferential on the narrow side and in the flat body and extended in the plane of a flat body edge part 22 Has. The edge part 20 has a the film cover 16 sealing sealing seam 18 through which a first connection electrode 22 and one of the first terminal electrode 22 electrically separated second connection electrode 24 of the galvanic element 13 from the slide 16 is guided. The edge part 20 is at least partially in a the sealing seam 18 covering holding structure 40 . 48 . 50 embedded in adhesive material.

LIST OF REFERENCE NUMBERS

10, 10 ', 10' '

 accumulator

12

 galvanic cell

13

 galvanic element

14

 flat body

15, 17

 foil

16

 film cover

18

 sealing seam

20

 edge part

21

 outer contour

22, 24

 terminal electrodes

28

 baseplate

30

 End plate

32

 mounting tabs

34, 34 '

 cooling channel

40, 40 ', 40 ", 48, 48', 48", 50

 Caterpillars of adhesive material

52, 52 ', 52' '

 accumulators wall

54

 investment

56, 58

 robot

60

 turntable

62

 axis of rotation

64

 arrow

Claims (13)

Accumulator ( 10 ) with at least one galvanic cell ( 12 ) comprising a galvanic element (1) extending in one plane, designed as a flat body with a narrow side ( 13 ) surrounding film wrapper ( 16 ) with a circumferential on the narrow side of the flat body and extended in the plane of the flat body edge part ( 20 ), one has the foil cover ( 16 ) sealing sealing seam ( 18 ), through which a first connection electrode ( 22 ) and one of the first connection electrode ( 22 ) electrically separated second connection electrode ( 24 ) of the galvanic element ( 13 ) from the foil cover ( 16 ), characterized in that the edge part ( 20 ) at least partially into a sealing seam ( 18 ) covering holding structure ( 40 . 48 . 50 ) is embedded from adhesive material. Accumulator according to claim 1, characterized in that the galvanic element ( 13 ) between a first and a second film ( 15 . 17 ) arranged with one in the edge part ( 20 ) circumferential sealing seam ( 18 ), the support structure ( 40 . 48 . 50 ) of adhesive material, the sealing seam ( 18 ) covers on both sides. Accumulator according to claim 1 or 2, characterized in that the support structure ( 40 . 48 . 50 ) the outer contour ( 21 ) of the edge part ( 20 ) surrounds. Accumulator according to one of claims 1 to 3, characterized in that the adhesive material is an elastomer and / or a plastic from the following group: acrylonitrile-butadiene acrylates, acrylonitrile-methyl methacrylates, butadiene rubbers, butyl rubbers, ethylene-ethyl acrylate copolymers, Ethylene-propylene copolymers, ethylene-propylene-diene rubbers, ethylene-vinyl acetates, fluororubbers, isoprene rubbers, polyisobutylenes, styrene-butadiene rubbers, styrene-butadiene-styrenes, vinyl chloride / ethylene, natural rubber or silicone rubber, silanes, polyvinyl chlorides (PVC) Plastisols), polyurethanes (1K-PUR, 2K-PUR), PMMA plastisols (polymethyl methacrylates) and epoxy resins. Accumulator according to one of claims 1 to 4, characterized in that the first and second connection electrode ( 22 . 24 ) by the support structure ( 40 . 48 . 50 ) are passed from adhesive material and one together with at least a portion of the edge part ( 20 ) in the support structure ( 40 . 48 . 50 ) of adhesive material embedded intermediate section. Accumulator according to one of claims 1 to 5, characterized in that the adhesive material, the peripheral edge part ( 20 ) of the film casing ( 16 ) surrounds. Accumulator according to one of Claims 1 to 6, characterized by a stack with a large number of galvanic cells ( 12 ), each having a galvanic element (FIG. 1) extending in one plane and designed as a flat body with a narrow side (FIG. 13 ) surrounding film wrapper ( 16 ) with a circumferential on the narrow side of the flat body and extended in the plane of the flat body edge part ( 20 ) which have a foil wrapper ( 16 ) sealing sealing seam ( 18 ), through which a first connection electrode ( 22 ) and one of the first connection electrode ( 22 ) electrically separated second connection electrode ( 24 ) of the galvanic element ( 13 ) from the foil cover ( 16 ), wherein the peripheral edge part ( 20 ) at least partially into a sealing seam ( 18 ) covering the galvanic cell ( 12 ) associated holding structure ( 40 . 48 . 50 ) is embedded from adhesive material. Accumulator according to claim 7, characterized in that the one galvanic cell ( 12 ) associated holding structure ( 40 ) on a base plate ( 28 ) or an end plate ( 30 ) or at one of a neighboring galvanic cell ( 12 ) associated holding structure ( 48 ) is determined from adhesive material. Accumulator according to claim 7 or 8, characterized in that the galvanic cells ( 12 ) associated holding structures ( 40 . 48 . 50 ) an accumulator wall ( 52 ) form. Accumulator according to claim 9, characterized in that the accumulator wall ( 52 ' . 52 '' ) a fluid channel ( 34 . 34 ' ) for a cooling medium. Method for producing a rechargeable battery (according to one of Claims 1 to 10) ( 109 in which on a base plate ( 28 ) a first caterpillar ( 40 ) is applied from adhesive material whose course the course of the edge part ( 20 ) of the galvanic cell ( 12 ), in which the galvanic cell ( 12 ) in the area of the border ( 20 ) arranged connecting seam ( 18 ) on the first caterpillar ( 40 ) and then on the first caterpillar ( 40 ) another caterpillar ( 48 ) is applied from adhesive material whose course of the course of the edge part ( 20 ) of the galvanic cell ( 12 ) and the edge portion of the galvanic cell with the first bead ( 40 ) and creates a holding structure of adhesive material, in which the edge part ( 20 ) of the galvanic cell ( 12 ) is embedded. Method according to claim 11, characterized in that with the first bead ( 40 ' . 40 '' ) and the second caterpillar ( 48 ' . 48 '' ) to the edge part ( 20 ) of the galvanic cell ( 12 ) substantially vertically extending fluid channel ( 34 . 34 ' ) is formed. Contraption ( 54 ) for producing a rechargeable battery (according to one of claims 1 to 10) ( 10 ) with a method according to claim 11 or 12, characterized by An institution ( 58 ) for handling a tool ( 59 ), with which a caterpillar ( 40 ) can be applied from adhesive material whose course the course of the edge part ( 20 ) of the galvanic cell ( 12 ) and a gripper device ( 56 ), with which the galvanic cell ( 12 ) in the spent caterpillar ( 40 ) can be inserted from adhesive material.

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