EP2617085A1

EP2617085A1 - Electrochemical energy storage device having flat cells and spacing elements

Info

Publication number: EP2617085A1
Application number: EP11758392.2A
Authority: EP
Inventors: Tim Schaefer; Jens Meintschel
Original assignee: Li Tec Battery GmbH
Current assignee: Li Tec Battery GmbH
Priority date: 2010-09-16
Filing date: 2011-09-07
Publication date: 2013-07-24
Also published as: US20130280590A1; KR20140004635A; DE102010045700A1; WO2012034667A1; CN103109395A; JP2013538001A

Abstract

The invention relates to an electrochemical energy storage device comprising a plurality of flat storage cells (2), which each have a first current conductor (18a) and a second current conductor (18b) on a narrow side of the storage cell (2); a plurality of spacing elements (4), which are each arranged between two storage cells (2) in order to maintain a predetermined distance between the storage cells (2); and a clamping apparatus (10) for clamping the storage cells (2) and the spacing elements (4) together to form a stack. The spacing elements (4) each have a first pressure surface (22a) and a second pressure surface (22b) on the two sides of the spacing element that face a storage cell (2). The one current conductor (18a, 18b) of the storage cells (2) is clamped by the clamping apparatus (10) between the first pressure surfaces (22a) of two spacing elements (4) by means of friction locking and the other current conductor (18b, 18a) of the storage cells (2) is clamped by the clamping apparatus (10) between the second pressure surfaces (22b) of two spacing elements (4) by means of friction locking. In the region of the first pressure surfaces (22a) and/or in the region of the second pressure surfaces (22b) of a spacing element (4), a contact element (26) is provided in order to establish an electrically conducting connection between the first or second pressure surfaces (22a, 22b) of a spacing element (4), and finally the spacing elements (4) and/or the contact elements (26) are designed in such a way that the compressions between the first pressure surfaces (22a) and between the second pressure surfaces (22b) are equal.

Description

Electrochemical energy storage device

with flat cells and spacers

Description

The present invention relates to an electrochemical energy storage device with flat cells and spacers.

It is known to build an electric energy storage device from a plurality of electrochemical storage cells, which are combined by means of a clamping device into a block. Such memory cells are, for example, so-called Pouch- or Coffeebag cells as flat and rectangular built memory cells for electric energy (battery cells, accumulator cells, capacitors, ...), whose electrochemically active part is surrounded by a foil-like packaging, through which electrical connections in sheet form , which are led so-called (current) arresters. The electrical series or parallel connection of the cells is effected by conductive contact elements, which establish the electrical connection between the corresponding current conductors of adjacent cells. It is common to arrange the cells in a stack, loosely received in a rack or pressed together by a clamp or the like, and to connect the above exposed poles or current conductor by suitable means. Such an electrochemical energy storage device is described, for example, in WO 2010/081704 A2.

It is an object of the present invention to provide an improved electrochemical energy storage device in which a plurality of arranged flat memory cells arranged on a narrow side current arresters in a stable block, securely fixed and reliably interconnected.

The object is achieved by an electrochemical energy storage device having the features of independent claim 1. Preferred embodiments and further developments of the invention form the subject of the dependent claims.

The electrochemical energy storage device of the invention comprises a plurality of flat memory cells each having a first current collector and a second current collector on a narrow side of the memory cell; a plurality of spacers each disposed between two memory cells for maintaining a predetermined distance between the memory cells; and a chuck for clamping the memory cells and spacers to a stack. The spacer elements each have on their two sides, which face a memory cell, a first pressure surface and a second pressure surface. In this case, in each case one current conductor of the memory cells between the first pressure surfaces of two spacer elements is clamped by means of frictional connection by the clamping device and the other current conductor of the memory cells between the second pressure surfaces of two spacer elements is clamped by means of adhesion by the clamping device. Furthermore, in each case in the region of the first pressure surfaces and / or in the region of the second pressure surfaces of a spacer element, a contact element for producing an electrically conductive connection between the first and second pressure surfaces of a spacer element is provided. In addition, the spacer elements and / or the contact elements are designed such that the compressions between the first pressure surfaces and between the second pressure surfaces are aligned with each other.

Since the current collector of the memory cells in each case between the first and second pressure surfaces of two spacer elements by means of adhesion through the Clamping means are clamped, a predetermined distance between adjacent memory cells of the cell block is maintained, which can be adjusted so that no clamping force is exerted on an electrochemically active part of the memory cells. This has advantages in terms of reliability, durability and temperature management of the memory cells.

Further, since contact elements for electrically connecting the first and / or second pressure surfaces are provided in the region of the pressure surfaces, the current conductors of adjacent cells can be electrically connected without additional connectors in the desired manner (i.e., series connection or parallel connection). The contact elements can be pre-assembled with the spacer elements or form a spacer itself; this facilitates the assembly. Further, since the contact elements are clamped as part of the spacer elements on the clamping device with and therefore held stationary, they can not be lost during operation of the device or are no further security measures required to prevent such.

Finally, since the compressions between the first pressure surfaces and between the second pressure surfaces are substantially equal to one another, the forces exerted on the current conductors of the memory cells via the first and second pressure surfaces can be absorbed and distributed uniformly and become engaged during clamping by the tensioning device one-sided yielding of the spacers and warping of the overall structure of the stack avoided.

In the present case, an "electrochemical energy storage device" is understood to mean any type of energy store which can be removed from electrical energy, wherein an electrochemical reaction takes place in the interior of the energy store can be connected in parallel to store a larger amount of charge or to achieve a desired operating voltage to be connected in series or form a combination of parallel and series connection.

In the present case, an "electrochemical cell" or "electrochemical energy storage cell" is understood to mean a device which serves to deliver electrical energy, the energy being stored in chemical form. In the case of rechargeable secondary batteries, the cell is also designed to receive electrical energy, convert it to chemical energy, and store it.

In the context of the present invention, a "current conductor" is to be understood as meaning an electrically conductive design element of an electrochemical storage cell which serves to transport electrical energy into or out of the storage cell In the other words, each electrode of the electrode stack of the memory cell has its own current conductor or the electrodes of the same polarity of the electrode stack are connected to a common current conductor. Accordingly, each memory cell has a first current conductor (eg for the positive pole connection) and a second current conductor (eg for the negative pole connection) .The shape of the current conductor is in the form of the memory cell or adapted to their electrode stack.

Preferably, the spacer elements also each have on their two sides, which face a memory cell, in the region of a narrow side, to which the current conductors of the memory cell are not arranged, a third pressure surface. The spacer elements and / or the contact elements are then designed so that the compressions between the first pressure surfaces, between the second pressure surfaces and between the third pressure surfaces are aligned with each other. The third pressure surface of the spacer elements is preferably provided in the region of a narrow side of the spacer elements opposite the first and second pressure surfaces. Alternatively, the third pressure surface can also be provided in the region of a narrow side of the spacer elements, which adjoins the narrow side on which the first and second pressure surfaces are provided. It is also possible to provide third pressure surfaces in several areas of the plurality of narrow sides of the spacer elements.

With the help of the third pressure surfaces of the spacer elements, the memory cells of the stack can be advantageously held at a further location. Preferably, the third pressure surfaces of two adjacent spacer elements take up a portion of an enclosure of the memory cell or a sealed seam of such an enclosure between them.

In a preferred embodiment of the invention, the memory cells of the stack are connected in series. For this purpose, the memory cells are preferably stacked one behind the other in such a way that the first current conductors and the second current conductors of the memory cells are arranged alternately one behind the other. In addition, a contact element for producing an electrically conductive connection between these one pressure surfaces of the spacer is provided in each case in the region of the one pressure surfaces of a spacer element and is in the region of the other pressure surfaces of a spacer an insulating construction for forming an electrical insulation between these other pressure surfaces of the spacer intended.

In a further preferred embodiment of the invention, the memory cells of the stack are connected in parallel. For this purpose, the memory cells are preferably stacked one behind the other in such a way that the first ones of the first current conductors of all the memory cells are arranged one behind the other and the second current collector of all memory cells are arranged one behind the other. In addition, a contact element for producing an electrically conductive connection between the first and second pressure surfaces of a spacer element is in each case provided in the region of the first pressure surfaces and in the region of the second pressure surfaces of a spacer element.

The tensioning device preferably has a plurality, preferably two or four, of tie rods which extend through bores in the first and second current conductors. By such an arrangement, the clamping force is concentrated where the clamping force is supposed to act, namely on the current conductors.

To avoid short circuits, the tie rods are preferably sheathed with an electrically insulating material or surrounded by a continuous insulating sleeve.

Preferably, the contact elements are formed of an electrically conductive material and received in the spacer elements. The insulating structures preferably each have at least one support element of an electrically insulating material (preferably glass or ceramic material), which is accommodated in the respective spacer element.

By thus formed and arranged contact elements or support elements of the material used for the specific tasks of contacting and support can be minimized and the total weight can be reduced by saving the usually heavier material for contacting. Particularly preferably, the end face of the support elements is at least the same size, in particular larger than the end face of the contact elements. So can the Verpresskräfte reliably absorbed and damage spacers are avoided.

Preferably, the contact elements and the support elements are substantially sleeve-shaped and received in corresponding recesses in the spacer elements. The tensioner, i. Preferably, the tie rods then preferably pass through this sleeve-shaped Kontaktbzw. Support elements through. In an alternative preferred embodiment, the contact and / or support elements are strip-shaped and received in corresponding recesses in the spacer elements and provided with through holes, in which run the tie rods. In a further preferred alternative, the spacer elements are formed completely as a support element or as a contact element. In all cases, a particularly space-saving arrangement is achieved in which contacting and clamping are realized by concentric components. In addition, we concentrated the clamping force of the clamping device on the contact elements and therefore achieved a particularly reliable electrical contact.

Preferably, each spacer element is formed as a substantially four-sided frame. In this case, two parallel frame sides are in each case in particular formed with pressure webs with first / second or third pressure surfaces lying opposite the end face. Thus, each memory cell is arranged in the stacking direction between two frames, and the distance of the spacer elements transversely to the stacking direction is fixed by the connecting the pressure bridges frame sides. Therefore, the stack of memory cells and spacers already stabilizes during assembly itself.

Particularly preferably, the stack has two conductive, preferably frame-shaped pressure end pieces, which rest on the first or last spacer element in the stacking direction, clamped on the clamping device with the stack are and are electrically connected in each case via the contact elements in the first and last spacer element with a current collector of the first or last memory cell. In this way, the end pieces serve as poles of the electrochemical energy storage device, on which the total voltage can be tapped.

The invention is particularly advantageous in lithium-ion batteries applicable. The foregoing and other features, objects and advantages of the present invention will become more apparent from the following description made with reference to the accompanying drawings. In it show, mostly schematic and not always true to scale:

1 is a perspective view of a cell block according to the invention in the assembled state. an exploded perspective view of the cell block of Figure 1 according to a first embodiment in partially assembled state. a partial plan view of the cell block of Figure 2 in horizontal longitudinal section.

Fig. 4 is an enlarged view of the detail IV in Fig. 3;

5 shows a frame of the cell block of FIG. 2 with contact elements in FIG

Exploded view;

Fig. 6 is a schematic plan view of a narrow side of the cell block of Fig. 2 for explaining the series connection of the memory cells; FIG. 7 shows a frame of a cell block according to a second exemplary embodiment in a view corresponding to FIG. 5; FIG. 8 is an enlarged partial view of a cell block according to a third

Embodiment in a Fig. 4 analog view;

9 shows a frame of the cell block of FIG. 8 with contact elements in FIG

Exploded view; a schematic plan view of a narrow side of the cell block of Figure 8 for explaining the parallel connection of the memory cells. and FIG. 11 is an enlarged partial view of a cell block according to a fourth embodiment

Embodiment in a Fig. 4 corresponding view.

A first embodiment of the present invention will now be described with reference to FIGS. 1 to 6. 1 is a perspective view of a cell block 1 of the present invention in the assembled state; Fig. 2 is an exploded perspective view of the cell block 1 according to the first embodiment in a partially assembled state; Fig. 3 is a partial plan view of the cell block 1 in horizontal longitudinal section in a plane "III" in Fig. 1. Fig. 4 is an enlarged view of a detail "IV" in Fig. 3; FIG. 5 shows a spacer element from FIG. 2 with a contact element in an exploded view; FIG. and FIG. 6 shows a partial plan view of a narrow side of the cell block of FIG. 2.

1, a cell block 1 has a plurality of memory cells 2 (galvanic cells, accumulator cells or the like, only one visible in FIG. 1), a plurality of intermediate frames 4 serving as spacers, two end frames 6, two pressure glasses 8 and four tie rods 10 with both sides mounted nuts 12 as a clamping device. One of the two end frames 6, the intermediate frame 4 and the second of the two end frames 6 form a stack which is held together by means of the tie rods 10 and the nuts 12 via the pressure glasses 8 arranged at the end. The memory cells 2 are located within the structure formed by the stacked frames 4, 6.

FIG. 2 shows the cell block 1 from FIG. 1 in a perspective partial exploded view. That the nuts 12 are removed and on the viewer side facing the pressure gland 8, the end frame 6, a memory cell 2 and an intermediate frame 4 are deducted from the tie rods 10.

According to the illustration in FIG. 2, the memory cells 2 are constructed as so-called flat cells or pouch cells, each having a first current conductor 18a and a second current conductor 18b on a narrow side. In this embodiment, the memory cells 2 following one another in the stack are rotated relative to one another, so that in each case a second current conductor 18b follows in the stacking direction on a first current conductor 18a and vice versa. In this way, a series connection of the memory cells 2 can be formed, as illustrated in FIG. 6.

Furthermore, each memory cell 2 has an active part 14, a sealing seam (an edge region) 16 and the two current conductors 18a, 18b. In the active part 14 take place the electrochemical reactions for storage and delivery of electrical energy. In principle, any type of electrochemical reaction can be used to construct the memory cells; However, the description relates in particular to lithium-ion batteries, to which the invention is particularly well applicable due to the requirements of mechanical stability and heat balance and economic importance. The active part 14 is sandwiched by two films, wherein the protruding edges of the films are gas-tight and liquid-tight welded together and form the so-called sealed seam 16. As shown in FIGS. 2 and 3, a positive first current collector 18a and a negative second current collector 18b project from a narrow side of the memory cell 2. In each case at least one bore 20 (hereinafter referred to as pole bore) is present in the current conductors 18a, 18b.

The memory cells 2 are threaded with the pole holes 20 on the tie rods 10, in such a way that in each case a memory cell 2 is arranged either between two intermediate frame 4 or between an intermediate frame 4 and an end frame 6. The frames 4, 6 are constructed so that the active part 14 of the memory cells 2 in the cavity of the frame 4, 6 is arranged, while first and second pressure surfaces 22a, 22b press against the flat sides of the current conductors 18a, 18b and this after tightening the Retain tie rod 10 and nuts 12. Preferably, third pressure surfaces 23 of the frames 4, 6 take up a part of the sealing seam 16 of the memory cells 2 between them in order to also position the ends of the memory cells 2 facing away from the current conductors 18a, 18b in the cell block 1 at a distance. The sides of the frames 4, 6 are also referred to as pressure bridges.

The frames 4, 6 furthermore have bores 24 arranged in their pressure surfaces 22a, 22b, 23, in which part sleeve-shaped contact elements 26, 27 are accommodated. More specifically, 4 contact elements 26 are arranged in the intermediate frame and 6 contact elements 27 are arranged in the end frame, which differ only in their lengths (in the stacking direction), since the intermediate frame 4 are thicker than the end frame 6. The holes 24 and the contact elements 26, 27 are aligned with the pole holes 20 in the current conductors 18a, 18b of the memory cells 2. Thus, the frame 4, 6 threaded with their holes 24 and contact elements 26, 27 via the tie rods 10. As can be seen in particular in FIGS. 4 to 6, in each intermediate frame 4 only one contact element 26 is received in a bore 24, either in the region of the first pressure surfaces 22a or in the region of the second pressure surfaces 22b. In addition, the contact elements 26 are alternately arranged in the intermediate frame 4, that is, in two successive stack in the intermediate frame 4, the contact element 26 is provided in the bore 24 in the region of the first pressure surfaces 22a in a first intermediate frame 4, while in a second intermediate frame 4, the contact element 26 is provided in the bore 24 in the region of the second pressure surfaces 22b.

In the case of an intermediate frame 4, the contact elements 26 thereby make electrical contact between the current conductors 18a, 18b of the memory cells 2 arranged on the respective pressure surfaces 22a, 22b, while in the case of an end frame 6, the contact sleeves 27 make electrical contact between one another produce positive and negative current conductors 18a, 18b of a memory cell 2 and one of the pressure goggles 8. In the area of the respective other pressure surface 22b, 22a, in which no contact elements are arranged, the frame 4, 6 forms an electrical insulation between the current conductors 18b, 18a of two memory cells 2 or the current conductor 18b, 18a and the pressure goggles 8.

As a result of the alternately rotated memory cells 2 and the alternating arrangement of the contact elements 26 in the bores 24 of the intermediate frames 4, all the memory cells 2 in the cell block 1 are connected to one another "positive-to-negative", ie a series connection of the memory cells 2 in FIG the cell block 1 realized. Moreover, the current collector 18a, 18b of the first and last memory cell 2 in the cell block 1 not connected to another memory cell 2 is connected to the respective pressure gland 8 via the contact element 27 in the respective end frame 6, so that the pressure goggles 8 have a positive pole and a negative pole form, where the pole voltage of the entire cell block 1 is applied. The frames 4, 6 are, as described above, made of a low cost, electrically insulating material such as plastic, solid or fiber reinforced. In contrast, the contact elements 26, 27 are made of an electrical conductor such as copper or brass, bronze or other copper alloy or other metal or other metal alloy, with or without the conductivity-enhancing coating such as silver or gold ,

The contact elements 26, 27 are based on the back of the current conductors 18a, 18b against the material of the frame 4, 6 from. If the material of the frame 4, 6 is more compliant than the material of the contact elements 26, 27, to avoid uneven compression of the frame 4, 6 on both lateral sides by appropriate measures to ensure that the compliance of the frame 4, 6 on the Side without contact element (insulating side) of Gesamt- yielding of frame material and sleeve material on the side with the contact elements 26, 27 (contact side) corresponds. Suitable measures for matching the overall upsets or stiffnesses on both lateral sides of the frames 4, 6, for example, an increased fiber content on the insulating side in the case of a fiber-reinforced plastic; different material or raw material compositions on insulating and contacting side; the use of stiffening inserts on the insulating side; and a larger web width, at least supporting web width, on the insulating side. These measures can be carried out individually or in combination in order to arrive at the desired result.

In Fig. 3, which shows a horizontal longitudinal sectional view of the cell block 1 in a plane III in Fig. 1, the changeable arrangement of the contact elements 26 in the intermediate frame 4 and the contact elements 27 in the end frame 6 can be seen. Likewise, the structure of the intermediate frame 4 and the end frame 6 can be seen. The frames 4, 6 are formed so that the first and second pressure surfaces (22a and 22b, not designated in the figure) on the opposite flat sides of the current collector 18a, 18b of the memory cells Press 2. They also have a thickness such that an air gap 30 is formed between the active parts 14 of the memory cells 2. On the one hand, this air gap 30 keeps mechanical pressure loads away from the active parts 14, so that traceable disturbances in the electrochemical function are avoided. On the other hand, cooling of the storage cells 2 is possible via the air gap 30.

The end frames 6 have, as well visible in Fig. 3, a smaller thickness than the intermediate frame 4. This takes into account the fact that only one side of the end frame 6, a memory cell 2 is arranged. Accordingly, the contact elements 27, which are arranged in the end frame 6, also shorter than the contact elements 26, which are arranged in the intermediate frame 4. FIG. 4 shows the contacting region between two memory cells 2 as a detail IV in FIG. 3. The air gap 30 between the active parts 14 of the memory cells 2 can also be clearly seen. By free cuts 32, 33 in the pressure surfaces 22a and 22b of the intermediate frame 4 ensures that the pressure surfaces 22a, 22b exert pressure only on the respective current collector 18a, 18b, but not on the other edge region of the memory cells 2 with the sealed seam 16. The cutouts 32 on the insulating side are deeper than on the contacting side. The end frame 6, in contrast to the intermediate frame 4 only on a flat side cutouts 32, 33. The tie rod 10 carries a continuous sleeve 34 made of an insulating material, in addition, a distance 36 is provided between the tie rod 10 and the components penetrated by it. As a result, the tie rod 10 with respect to the conductive or floating parts, so the current conductors 18a, 18b, the pressure goggles 8 and the contact sleeves 26, 27 electrically isolated, and a short circuit is effectively avoided. Although not shown in detail in the figure, the frames 4, 6, the pressure goggles 8 and the memory cells 2 are kept radially centered so that between the tie rods 10 and the conductive or floating parts 18a, 18b, 26, 27, 8, the distance 36 is always respected; Suitable means for centering are about dowel pins or a geometrically matched shape of the stacked components. Also not shown in the figures, is also provided for a suitable isolation of the nuts 12 against the pressure goggles 8; This can be done for example by insulating discs or collar bushings whose cylinder part protrudes into the respective pressure gland 8.

For the construction of the memory cells 2, it can be seen in FIG. 4 that the current arresters 18a, 18b of the plus and minus sides have different thicknesses. Also here are the foils 38 for wrapping the active parts 14 of the memory cells 2 to see.

In Fig. 5, an intermediate frame 4 is shown individually in perspective view with the first pressure surfaces 22a, the second pressure surfaces 22b, the third pressure surfaces 23, the holes 24 and the cutout 33. In the one bore 24 of the intermediate frame 4, which is arranged in the region of the second pressure surfaces 22b, a sleeve-shaped contact element 26 is used in this case.

FIG. 6 again illustrates the sequence of the first and second current conductors 18a, 18b of the memory cells 2 and the corresponding alternately arrangement of the contact elements 26 for realizing the series connection of the memory cells 2 of the cell block 1.

Now, a second embodiment of the present invention will be described with reference to FIG. 7. The view of FIG. 7 corresponds to that of FIG. 5 for the first embodiment. As shown in Fig. 7, in the intermediate frame 4 of the cell block 1 sleeve-shaped contact elements 26 made of an electrically conductive material and sleeve-shaped support members 42 made of an electrically insulating material added. In this case, a contact element 26 is disposed in the bore 24 in the region of a pressure surfaces 22b of the intermediate frame 4 and a support member 42 in the bore 24 in the region of the other pressure surfaces 22a of the intermediate frame 4 is arranged. The positions of the contact elements 26 and the support elements 42 are alternately selected in the intermediate frame 4, which is successive in the cell block 1, in order to realize the series connection of the memory cells 2 explained above in connection with the first exemplary embodiment. The end frame 6 of the cell block 1 have in this embodiment, according to additional, arranged on the side of the insulating pressure surfaces support sleeves in addition to the contact sleeves 27.

The support elements 42 are made of a material having a contact elements 26, 27 corresponding to the flexibility or strength. Therefore, the contact sleeves 26, 27, which rest against the current conductors 18a, 18b of the memory cells 2, can be effectively supported on the support sleeves which rest on the rear side of the current conductors 18a, 18b. A one-sided compression of the frame 4, 6 is therefore avoided as well as a sinking of the contact sleeves 26, 27 and thereby caused deformation of the current collector 18a, 18b.

Optionally, the support sleeves 42 may have a larger outer diameter than the contact sleeves 26 in order to develop a particularly effective support effect. The support sleeves 26 are made of a hard, electrically insulating material such as a glass or ceramic material or a hard, possibly fiber-reinforced plastic. The above statements apply mutatis mutandis to the support sleeves which are arranged in the end frame 6.

Incidentally, the cell block of this embodiment is substantially the same as that of the first embodiment described above. Now, a third embodiment of the present invention will be described with reference to FIGS. 8 to 10. The views of FIGS. 8 to 10 correspond to those of FIGS. 4 to 6 for the first embodiment. The memory cells 2 of the cell block 1 are connected in parallel in this embodiment. For this purpose, between all the first and second pressure surfaces 22a, 22b of the spacer elements serving as intermediate frame 4 contact elements 26 are arranged in the bores 24 of the intermediate frame. In addition, all the memory cells 2 of the cell block 1 are arranged the same, so that the first current collector 18a of all memory cells 2 are arranged one behind the other and next to the second current collector 18b of all memory cells 2 are arranged one behind the other.

Incidentally, the cell block of this third embodiment substantially corresponds to that of the first embodiment described above.

Now, a fourth embodiment of the present invention will be described with reference to FIG. 11. In this case, the view of FIG. 11 corresponds to that of FIG. 4 for the first exemplary embodiment.

11 shows the contacting region between a first current conductor 18a of a memory cell 2 and a second current conductor 18b of an adjacent memory cell 2. As shown in FIG. 11, a contact spring 44 is provided in the contacting region of the intermediate frame 4, which makes contact between the current conductors 18a, 18b of the two adjacent memory cells 2 produces. The contact spring 44 is made of a good conductor material (see above) and has a U-shaped profile. The contact spring 44 is attached from the outside to the first and second pressure surfaces 22a, 22b of the intermediate frame 4. The intermediate frame 4 has at this point a smaller thickness than in the remaining area, and the inner width of the U-profile of the contact spring 44 corresponds to the Thickness of the intermediate frame 4 at this point. The outer width of the U-profile of the contact spring 44 corresponds to the thickness of the intermediate frame 4 outside the pressure surfaces 22a and 22b to be contacted. The contact spring 44 has in its protruding legs bores which are aligned with the bores 24 in the pressure surfaces 22a and 22b of the intermediate frame 4 and have the same diameter.

The above explanations also apply to the end frames, which are not shown in detail for this embodiment. There, contact springs are to be used with a smaller width corresponding to the smaller thickness of the end frame.

The contact springs 44 provide no significant resistance to the pressure applied by the tie rods, so that no asymmetrical compression in the contacting and insulating regions of the intermediate frame 4 arise. The contact springs 44 extend over the entire height of the pressure ridge of the frame, so that a notch of the pressure surfaces 22a, 22b is not to be expected. In a modification, the contact springs 44 are provided on the laterally exposed surface with an insulating coating or there is provided an insulating cover.

Incidentally, the cell block of this fourth embodiment substantially corresponds to that of the first embodiment described above. In addition, the cell block of the fourth embodiment can also be combined with the insulating support members 42 of the second embodiment. In addition to the embodiments described above, further embodiments of the invention are conceivable for the person skilled in the art. Thus, in a modification, instead of the above-described end and intermediate frames, rocker-shaped spacers (spacing or mounting bolts) are used, which together form the frame described above. The spacer bars have bores and contact elements as described above and, like the frames on a lateral side of the cell block, are threaded onto the tie rods in alternation with the current conductors of the memory cells. Since the tie rods are fixed by the pressure goggles in their radial position, after tightening on the pressure goggles forms a rigid and stable block, which is easier than a cell block with frame due to the lower material usage. Optionally, the pressure goggles will be thicker than in the embodiments described above or have stiffeners. Instead of sleeves or contact springs, the spacer bars can be made entirely of a conductor material or of an electrically insulating material, wherein the material chosen for the insulating spacer bars is one which has a printed material conformed to the pressure compliance.

In a further modification spacer bars are as described above in corresponding recesses of the frame 4, 6 held.

In another modification, two or more tie rods are used per conductor.

List of reference numerals:

1 cell block

2 memory cell

4 spacer element, intermediate frame

6 end frame

8 pressure glasses

10 tie rods

12 mother

14 active part of 2

16 sealed seam of 2

18a first current conductor of 2

18b second current collector of 2

20 pole hole in 18a or 18b

22a first printing surface of 4, 6

22b second printing area of 4, 6

23 third printing area of 4, 6

24 hole in 4, 6

26, 27 contact element, contact sleeve

28 hole in 8

30 air gap

32, 33 Free cut in 4, 6

34 coating or sleeve of 10

36 distance

38 wrapping film of 2

40 hole in 4

42 support sleeve

44 contact spring

Claims

P a n t a n s p r e c h e

Electrochemical energy storage device, with

a plurality of flat memory cells (2), each having a first

Current conductor (18 a) and a second current collector (18 b) at one

Have narrow side of the memory cell (2);

a plurality of spacer elements (4), each between two

Memory cells (2) are arranged to maintain a predetermined distance between the memory cells (2); and

a tensioning device (10) for clamping the memory cells (2) and

Spacer elements (4) to a stack,

wherein the spacer elements (4) each have a first pressure surface (22a) and a second pressure surface (22b) on their two sides which face a memory cell (2),

wherein in each case one current conductor (18a, 18b) of the memory cells (2) between the first pressure surfaces (22a) of two spacer elements (4) by means of frictional connection by the clamping device (10) is clamped and the other current conductor (18b, 18a) of the memory cells (2 ) between the second pressure surfaces (22b) of two spacer elements (4) is clamped by means of adhesion by the clamping device (10),

wherein a contact element (26) for producing an electrically conductive connection between the first and second pressure surfaces (22a, 22b) of a

Distance element (4) is provided, and

wherein the spacer elements (4) and / or the contact elements (26) are configured so that the compressions between the first pressure surfaces (22a) and between the second pressure surfaces (22b) are aligned with each other. Energy storage device according to claim 1,

characterized in that

the spacer elements (4) in each case on its two sides facing a memory cell (2), in the region of a narrow side, on which the current conductors (18a, 18b) of the memory cell (2) are not arranged, have a third pressure surface (23) ; and

the spacer elements (4) and / or the contact elements (26) are designed so that the compressions between the first pressure surfaces (22a), between the second pressure surfaces (22b) and between the third pressure surfaces (23) are aligned with each other.

Energy storage device according to claim 1 or 2,

characterized in that

the memory cells (2) are stacked one behind the other in such a way that the first current conductors (18a) and the second current conductors (18b) of the memory cells (2) are arranged alternately one behind the other; and

a contact element (26) for producing an electrically conductive connection between these one pressure surfaces (22a, 22b) of the spacer element (4) is provided in each case in the region of the one pressure surfaces (22a, 22b) of a spacer element (4) and in the region of the other pressure surfaces ( 22b, 22a) of a spacer element (4) an insulating construction for forming an electrical insulation between these other pressure surfaces (22b, 22a) of the spacer element (4) is provided.

Energy storage device according to claim 1 or 2,

characterized in that

the memory cells (2) are stacked one behind the other such that the first ones of the first current conductors (18a) of all the memory cells (2) are arranged one behind the other and the second current conductors (18b) of all the memory cells (2) are arranged one behind the other; and

in each case in the region of the first pressure surfaces (22a) and in the region of the second pressure surfaces (22b) of a spacer element (4), a contact element (26) for producing an electrically conductive connection between the first and second pressure surfaces (22a, 22b) of a

Distance element (4) is provided.

Energy storage device according to one of the preceding claims, characterized in that

the tensioning device comprises a plurality of tie rods (10) extending through bores (20) in the first and second current conductors (18a, 18b), respectively.

the contact elements (26) are formed from an electrically conductive material and are received in the spacer elements (4).

Energy storage device according to one of claims 3, 5 and 6, characterized in that

the insulating structures each comprise at least one support element (42) made of an electrically insulating material, which is accommodated in the spacer element (4).

the contact elements (26) and / or the support elements (42) are substantially sleeve-shaped and are received in corresponding recesses (40) in the spacer elements (4); and the tensioning device (10) extends through the sleeve-shaped contact or support elements (26, 42). 9. Energy storage device according to one of the preceding claims, characterized in that the spacer elements (4) are each designed as a substantially four-sided frame.