Cell connector and method for producing a cell connector

Abstract

To create a cell connector for electrically conductively connecting at least one first cell terminal of a first electrochemical cell and at least one second cell terminal of a second electrochemical cell, comprising at least one first contact area, for electrically conductively connecting the cell connector to the at least one first cell terminal, at least one second contact area, for electrically conductively connecting the cell connector to the at least one second cell terminal, and at least one elastically and / or plastically deformable connection area, arranged in the flow path between the at least one first contact area and the at least one second contact area, the cell connector requiring little installation space and allowing a small distance between the electrochemical cells that are electrically conductively connected to one another by the cell connector, it is proposed that the connection area is formed at least partially from a work-hardened metallic material.

Description

[0001] Cell connector and method for producing a cell connector

[0002] The present invention relates to a cell connector for electrically connecting at least one first cell terminal of a first electrochemical cell and at least one second cell terminal of a second electrochemical cell, comprising at least one first contact region for electrically connecting the cell connector to the at least one first cell terminal, at least one second contact region for electrically connecting the cell connector to the at least one second cell terminal and at least one elastically and / or plastically deformable connecting region which is arranged in the current path between the at least one first contact region and the at least one second contact region.

[0003] Cell connectors for the electrically conductive connection of cell terminals of electrochemical cells of an electrochemical device have been used for a long time and are designed, for example, as aluminum bars, copper bars, bonding wires or cables.

[0004] The elastically and / or plastically deformable connection area of ​​a cell connector can comprise a mechanical compensation element. Such a compensation element can be designed, for example, as a wave, a bead, or a half-bead.

[0005] The at least one compensation element of the connection area can compensate for relative displacements of the cell terminals of the electrochemical cells electrically connected to one another by the cell connector, so that the forces acting on the cell terminals and the screw or joint connections by which the cell terminals are connected to the cell connector due to the relative displacements do not become excessive. The at least one compensation element must be as flexible as possible, but also capable of withstanding as many load cycles as possible, i.e., it must have high operational strength.

[0006] The relative movements of the cell terminals, which are to be compensated by at least one connection area, can result from operating loads such as shock, vibration or swelling of the electrochemical cells due to aging phenomena (so-called "swelling").

[0007] In addition to compensating for operating loads, the at least one compensation element can also serve, during the manufacture of the electrochemical device, to press the at least one first contact area or the at least one second contact area against the respective first cell terminal or the respective second cell terminal, respectively, in order to establish an electrically conductive connection, in particular by a welding process, for example, a laser welding process, in this held-down position of the cell connector at the respective cell terminal. Manufacturing tolerances are thereby compensated for with a low holding-down force.

[0008] In addition to providing the required mechanical flexibility, the cell connector must conduct the current between the electrochemical cells electrically connected by the cell connector, for which the cell connector should have the lowest possible ohmic resistance, low power loss and, consequently, a low temperature.

[0009] In known cell connectors for electrically connecting cell terminals of electrochemical devices, the compensation elements, such as a bead or a wave, are designed to be as high as possible (i.e., with a large extension along the contact direction or Z-direction of the electrochemical device), as long as possible (in particular, with a long plateau between two half-beads), and with large bending radii (to achieve the lowest possible mechanical stresses). This requires a large installation space for the cell connector and thus a large distance between the electrochemical cells, resulting in a low energy density of the electrochemical device.

[0010] Furthermore, a large number of compensation elements (e.g. waves, beads or half beads) are often used in the same connection area.

[0011] The present invention is based on the object of creating a cell connector of the type mentioned at the outset which requires little installation space and enables a small distance between the electrochemical cells which are electrically connected to one another by the cell connector.

[0012] This object is achieved according to the invention in a cell connector having the features of the preamble of claim 1 in that the connecting region is formed at least partially from a work-hardened metallic material.

[0013] By work hardening the metallic material, the material thickness can be reduced without also reducing the modulus of elasticity. This leads to greater flexibility or lower stiffness of the joint area.

[0014] Due to the increased flexibility resulting from the work hardening of the metallic material used, the forces acting on the connection point between each cell terminal and the cell connector can be reduced, thereby increasing the service life of the connection point in question.

[0015] Furthermore, work-hardening of the metallic material results in a strengthening effect, increasing its tensile strength and fatigue strength. This has a positive effect on the fatigue strength of the cell connector. Due to the higher fatigue strength in the region formed from the work-hardened metallic material, the at least one compensation element of the connection region, for example a wave, a bead, or a half-bead, can be designed with a lower height (i.e., with a smaller extension in the contact direction or Z-direction of the electrochemical device) and / or with a smaller extension perpendicular to the contact direction or Z-direction of the electrochemical device (for example, with shorter plateaus between two half-beads).

[0016] Alternatively or additionally, the bending radii of the at least one compensation element can be made smaller.

[0017] Each of the properties described above leads to a reduction in the space required for the arrangement of the cell connector.

[0018] Preferably, at least the at least one compensation element of the connecting region is formed at least partially from a work-hardened metallic material.

[0019] It is particularly advantageous if at least one compensation element of at least one connecting region of the cell connector is formed entirely from a work-hardened metallic material.

[0020] If the cell connector comprises a plurality of connecting regions, it is preferably provided that all connecting regions of the cell connector are formed at least partially from a work-hardened metallic material.

[0021] In particular, it can be provided that all connection areas of the cell connector each comprise at least one contact element, which is at least partially formed from a work-hardened metallic material. It is particularly advantageous if all connection areas of the cell connector each comprise at least one compensation element, which is formed entirely from a work-hardened metallic material.

[0022] In a preferred embodiment of the invention, it is provided that all contact elements of all connection areas of the cell connector are formed at least partially from a work-hardened metallic material.

[0023] It is particularly advantageous if all compensation elements of all connection areas of the cell connector are made entirely of a work-hardened metallic material.

[0024] The cell connector according to the invention comprises at least one first contact region for electrically connecting the cell connector to a first cell terminal and at least one second contact region for electrically connecting the cell connector to a second cell terminal.

[0025] In principle, the cell connector can comprise any number of first contact areas for electrically connecting the cell connector to a corresponding number of first cell terminals at a first electrical potential and any number of second contact areas for electrically connecting the cell connector to a corresponding number of second cell terminals at a second electrochemical potential.

[0026] In this way, any number of first cell terminals can be electrically connected in series with a corresponding number of second cell terminals.

[0027] Preferably, each first contact region and / or each second contact region of the cell connector is assigned an elastically and / or plastically deformable connection region. In particular, it can be provided that the cell connector comprises a web region, which is connected via one or more connection regions to a corresponding number of first contact regions of the cell connector, and is connected via one or more connection regions to a corresponding number of second contact regions of the cell connector.

[0028] In principle, the work-hardened metallic material can be any material that has a specific electrical conductivity sufficient for the required current-carrying capacity of the cell connector.

[0029] For example, the work-hardened metallic material may be a copper material. Such a copper material is preferably composed of more than 50% copper by weight.

[0030] However, in a preferred embodiment of the invention, it is provided that the work-hardened metallic material is an aluminum material.

[0031] Preferably, the aluminum material contains more than 50% by weight of aluminum, more preferably more than 99.0% by weight of aluminum.

[0032] The work hardening of the metallic material is preferably achieved by mechanical cold deformation of a starting material.

[0033] If the connecting area of ​​the cell connector is formed by a forming process from a preferably flat starting material, the work hardening of the material can in principle take place before the forming process, during the forming process or after the forming process.

[0034] To achieve the most homogeneous cold forming and thus the most homogeneous work hardening of the metallic material, it is advantageous if the work hardening takes place before the forming process of the joining area. Work hardening is preferably achieved by reducing the material thickness of a metallic starting material.

[0035] A measure of the cold deformation of the starting material is the degree of deformation E, with s = (ho - hi) / ho, where ho is the material thickness of the starting material before work hardening and hi is the material thickness of the work hardened metallic material after cold deformation.

[0036] Preferably, the degree of deformation s of the work-hardened metallic material is at least 10%, in particular at least 20%, particularly preferably more than 30%, for example more than 60%.

[0037] Furthermore, it is preferably provided that the degree of deformation s of the work-hardened metallic material is less than 80%.

[0038] Work-hardened metallic aluminum materials are designated according to the American standard ANSI H35.1, the international standard ISO 2107 and the European standard AUF 515 with designations that begin with the letter H and follow two or three digits.

[0039] The work hardening states H12 (1 / 4-hard), H14 (1 / 2-hard), H16 (3 / 4-hard) and H18 (hard) according to the above-mentioned standards are particularly suitable as work-hardened aluminum materials for the connection area of ​​the cell connector.

[0040] For the operational strength of the cell connector, it is particularly advantageous if the tensile strength m of the work-hardened metallic material is more than 90 N / mm 2 , preferably more than 100 N / mm 2 , especially more than 120 N / mm2 , particularly preferably more than 140 N / mm 2 , is. Furthermore, it has proven advantageous for the manufacturability of the connection area by a forming process if the tensile strength R m of the work-hardened metallic material less than 160 N / mm 2 amounts.

[0041] The work-hardened metallic material has preferably been hardened by a mechanical cold-forming process.

[0042] In particular, it can be provided that the work-hardened metallic material is work-hardened by a cold rolling process, a stamping process or a forming process with local reduction of the material thickness.

[0043] Before the work hardening process, the work hardened material may have been soft annealed.

[0044] The cell connector can basically comprise one layer, two layers or more than two layers in the connection area.

[0045] In a preferred embodiment of the invention, it is provided that the cell connector is formed in a single layer at least in the connection area.

[0046] It is preferably provided that the connecting region is formed substantially entirely from the work-hardened metallic material.

[0047] The connecting region preferably has at least one elastically and / or plastically deformable compensation element. The compensation element is preferably formed from the work-hardened material.

[0048] Such a compensation element can be designed, for example, as a wave, a bead or a half-bead.

[0049] In preferred embodiments of the invention, the connecting region comprises at least one wave, one step, one plateau, and / or one half-bead. A wave, one step, or one half-bead can extend out of the plane spanned by the connecting direction and the transverse direction of the cell connector, or they can be essentially flat and be limited to the plane spanned by the connecting direction and the transverse direction of the cell connector.

[0050] In order to reduce the thermal conductivity of the cell connector, it can be provided that the cell connector has at least one cross-section-reduced region in the current path between the at least one first contact region and the at least one second contact region, in which the electrically conductive cross-section of the cell connector is reduced by at least one recess.

[0051] Such a recess can in particular be designed as a passage opening which completely penetrates a base body of the cell connector from a first outer side of the cell connector to a second side of the cell connector.

[0052] It is particularly advantageous if the at least one region with a reduced cross-section is arranged in at least one connecting region of the cell connector, which is at least partially formed from a work-hardened metallic material.

[0053] For example, it can be provided that the cross-section-reduced region is arranged on a compensation element of such a connecting region.

[0054] The region of the cell connector formed from the work-hardened metallic material can extend into the at least one first contact region and / or into the at least one second contact region, since contact regions with a lower material thickness are easier to weld. In preferred embodiments of the invention, it is therefore provided that the at least one first contact region and / or the at least one second contact region of the cell connector are formed at least partially from a work-hardened metallic material.

[0055] In particular, it can be provided that the cell connector is formed substantially entirely from a work-hardened metallic material.

[0056] The cell connector according to the invention is particularly suitable for use as a component of a cell contacting system for an electrochemical device comprising a plurality of electrochemical cells, wherein the cell contacting system comprises at least one cell connector according to the invention.

[0057] Such a cell contacting system according to the invention is particularly suitable for use as a component of an electrochemical device comprising a plurality of electrochemical cells and a cell contacting system according to the invention.

[0058] Such an electrochemical device can be designed in particular as an energy storage device, for example for an electric vehicle or for a stationary storage application.

[0059] The electrochemical cells can in particular be designed as lithium-ion battery cells.

[0060] The present invention further relates to a method for producing a cell connector for electrically connecting at least one first cell terminal of a first electrochemical cell and at least one second cell terminal of a second electrochemical cell, wherein the cell connector comprises at least one first contact region for electrically connecting the cell connector to the at least one first cell terminal, at least one second contact region for electrically connecting the cell connector to the at least one second cell terminal and at least one elastically and / or plastically deformable connecting region which is arranged in the current path between the at least one first contact region and the at least one second contact region.

[0061] The present invention is based on the further object of creating such a method for producing a cell connector, by means of which a cell connector is created which requires little installation space and enables a small distance between the electrochemical cells which are electrically conductively connected to one another by the cell connector.

[0062] This object is achieved by a method for producing a cell connector of the type mentioned above, the method comprising the following:

[0063] Providing a metallic starting material;

[0064] Work hardening at least a portion of the metallic starting material to form a work hardened metallic material; and

[0065] Formation of at least one connecting region of the cell connector by forming the work-hardened metallic material or during the work-hardening of the metallic starting material to form the work-hardened metallic material.

[0066] It is preferably provided that the at least one connecting region is formed by forming the metallic material which has already been work-hardened before the forming process.

[0067] It has proven particularly advantageous if the metallic starting material is soft-annealed prior to cold-working. Particular embodiments of the method according to the invention for producing a cell connector have already been explained above in connection with particular embodiments of the cell connector according to the invention for electrically connecting cell terminals.

[0068] The method according to the invention for producing a cell connector is particularly suitable for producing the cell connector according to the invention.

[0069] The cell connector according to the invention is preferably produced by the method according to the invention for producing a cell connector.

[0070] Further features and advantages of the invention are the subject of the following description and the drawings of exemplary embodiments.

[0071] The drawings show:

[0072] Fig. 1 is a perspective view of a cell connector for electrically connecting a first cell terminal of a first electrochemical cell and a second cell terminal of a second electrochemical cell, wherein the cell connector comprises a first contact region for electrically connecting the cell connector to the first cell terminal, a second contact region for electrically connecting the cell connector to the second cell terminal, and an elastically and / or plastically deformable connecting region which is arranged in the current path between the first contact region and the second contact region, wherein the connecting region is formed from a work-hardened metallic material;

[0073] Fig. 2 shows a longitudinal section through the cell connector from Fig. 1; Fig. 3 shows a diagram showing the course of the 0.2% yield strength (R P o,2), the course of the tensile strength (R m) and represents the elongation at break (Aio) of aluminium as a function of the degree of deformation or cold rolling (s);

[0074] Fig. 4 is a perspective view of a contact region and a connection region of a cell connector formed from a work-hardened metallic material, and of a web region of the cell connector formed from a non-work-hardened metallic material;

[0075] Fig. 5 is a longitudinal section through the contact area, the deformation area and the web area of ​​the cell connector from Fig. 4;

[0076] Fig. 6 shows a longitudinal section through a first contact region, a connecting region and a second contact region of a cell connector, wherein the connecting region comprises a shaft as a compensation element;

[0077] Fig. 7 shows a longitudinal section through a first contact region, a connecting region and a second contact region of a cell connector, wherein the connecting region comprises a step or half-bead as a compensation element;

[0078] Fig. 8 shows a longitudinal section through a first contact region, a connecting region and a second contact region of a cell connector, wherein the connecting region comprises two (differently high) half beads as compensation elements;

[0079] Fig. 9 shows a longitudinal section through a first contact region, a connecting region, and a second contact region of a cell connector, wherein the connecting region comprises four half-beads as compensation elements; Fig. 10 shows a longitudinal section through a first contact region, a connecting region, and a second contact region of a cell connector, wherein the connecting region comprises two half-beads as elastically and / or plastically deformable compensation elements and further comprises a plateau arranged between the half-beads;

[0080] Fig. 11 shows a longitudinal section through a first contact region, a connecting region and a second contact region of a cell connector, wherein the connecting region comprises two half-beads as elastically and / or plastically deformable compensation elements and further comprises a plateau arranged between the half-beads, wherein the plateau has a greater length along a connecting direction of the cell connector pointing from the first contact region to the second contact region than the plateau of the cell connector from Fig. 10; and

[0081] Fig. 12 shows a longitudinal section through a first contact region, a connecting region and a second contact region of a cell connector, wherein the connecting region comprises two half-beads as elastically and / or plastically deformable compensation elements and further comprises a plateau arranged between the half-beads, wherein the heights of the half-beads in a contacting direction of the cell connector oriented perpendicular to the connecting direction of the cell connector have greater heights than the half-beads of the cell connector shown in Fig. 10.

[0082] Identical or functionally equivalent elements are designated by the same reference numerals throughout the figures. A cell connector 100 shown in Figs. 1 and 2 serves to electrically connect a first cell terminal 102 of a first electrochemical cell 104 and a second cell terminal 106 of a second electrochemical cell 108 (see Fig. 2).

[0083] The electrochemical cells 104 and 108 form components of a battery module 110 of an electrochemical device designated as a whole by 112, which may comprise a plurality of battery modules 110, each of which in turn comprises a plurality of electrochemical cells 104, 108.

[0084] The electrochemical device 112 can be designed in particular as an accumulator, in particular as a lithium-ion accumulator.

[0085] The electrochemical cells 104, 108 of the electrochemical modules can be designed accordingly as accumulator cells, in particular as lithium-ion accumulator cells.

[0086] The first cell terminal 102 can have positive or negative polarity; the second cell terminal 106 then has the opposite polarity, for example, the negative polarity or the positive polarity.

[0087] The cell connector 100 comprises a base body 114, which in turn has a first contact region 116, which is electrically conductively connected to the first cell terminal 102 of the first electrochemical cell 104 in the assembled state of the cell connector 100, and a second contact region 118, which is electrically conductively connected to the second cell terminal 106 of the second electrochemical cell 108 in the assembled state of the cell connector 100.

[0088] The base body 114 of the cell connector 100 is preferably manufactured as a stamped and bent part. In the embodiment shown in Figs. 1 and 2, the base body 114 of the cell connector 100 is formed entirely from a work-hardened metallic material.

[0089] The work-hardened metallic material is preferably an aluminum material.

[0090] In particular, it may be provided that the work-hardened metallic material contains more than 99.0% by weight of aluminum.

[0091] The degree of deformation s of the work-hardened metallic material is preferably at least 10%, in particular at least 20%, particularly preferably more than 30%, for example approximately 50%.

[0092] Furthermore, the degree of deformation s of the work-hardened metallic material is preferably less than 80%, in particular less than 60%.

[0093] In the diagram of Fig. 3, the course of the 0.2% proof stress (R P o,2), the tensile strength (R m ) and the elongation at break (Aio) of cold-hardened pure aluminum as a function of the degree of deformation or cold rolling degree s.

[0094] The degree of deformation s results from the original material thickness ho of the still unworked material and the material thickness difference Ah, by which the material thickness of the material is reduced by work hardening, to s = Ah / ho .

[0095] The work hardening of the metallic starting material, in particular aluminum, can be carried out, for example, by a cold rolling process or by a stamping process.

[0096] As can be seen from Fig. 3, the tensile strength Rm of the metallic material increases monotonically with increasing deformation degree or cold rolling degree s. If a soft-annealed aluminum sheet, whose state is designated Hill, is used as the metallic starting material, then before work hardening (i.e., at s = 0), it is in a soft initial state with a tensile strength of approximately 80 N / mm 2 .

[0097] If this starting material is work-hardened to a degree of deformation of 10%, it reaches the state H12 (1 / 4-hard), with an increased tensile strength of approximately 100 N / mm 2 .

[0098] If the annealed starting material is work-hardened to a degree of hardening of 20%, it reaches the state H14 (1 / 2-hard), in which the tensile strength is slightly above 110 N / mm 2 lies.

[0099] If the starting material is work-hardened to a degree of deformation of approximately 36%, it reaches the state H16 (3 / 4-hard), in which the tensile strength increases to approximately 125 N / mm 2 is increased.

[0100] If the starting material is work-hardened to a degree of deformation of approximately 62%, it reaches the H18 (hard) state, in which the tensile strength is approximately 145 N / mm 2 amounts.

[0101] If the starting material is work-hardened to a degree of deformation of approximately 86%, it reaches the H19 (extra hard) state, in which the tensile strength is approximately 172 N / mm 2 amounts.

[0102] At the preferred degree of deformation of s = 50%, the work-hardened aluminum material lies between the H16 and H18 states, with a tensile strength of approximately 136 N / mm 2 Such a cold-worked aluminum material exhibits particularly high flexibility and fatigue strength, which is advantageous for the formation of elastically and / or plastically deformable structures, particularly in a stamped and bent part.

[0103] In the assembled state of the cell connector 100, the first contact region 116 and the second contact region 118 of the cell connector 100 are connected by screwing or preferably by a material fit to the respectively assigned cell terminal 102 or 106.

[0104] Such a material connection is preferably produced by welding, in particular laser welding, or by soldering.

[0105] In order to enable direct access to the cell terminals 102 and 106, for example for measuring purposes, even after the cell connector has been firmly connected to the cell terminals 102 and 106, the first contact region 112 can be provided with a, for example substantially rectangular, through-opening 120 and / or the second contact region 118 of the base body 114 can be provided with a, for example substantially rectangular, through-opening 122.

[0106] During operation of the electrochemical device 112, due to different temperatures and / or different thermal expansion coefficients of the cell connector 100 on the one hand and a (not shown) receiving device for the electrochemical cells 104, 108 on the other hand, a difference can occur between a longitudinal expansion of the cell connector 100 on the one hand and a change in the distance between the longitudinal axis 124 of the first cell terminal 102 and the longitudinal axis 126 of the second cell terminal 106 on the other hand. A change in temperature changes the relative positions of the cell terminals 102, 106 connected to one another by the cell connector 100 in a connection direction 130 oriented perpendicular to the axial direction or contact direction 128 and / or in a transverse direction 132 oriented perpendicular to the contact direction 128 and perpendicular to the connection direction 130.

[0107] The connection direction 130 lies in a plane containing the longitudinal axes 124, 126 of the cell terminals 102 and 106 and runs parallel to a longitudinal direction 134 of the cell connector 100.

[0108] In particular, the connection direction 130 runs through a center of the passage opening 120 in the first contact region 116 and through a center of the passage opening 122 in the second contact region 118 of the cell connector 100.

[0109] Furthermore, due to different longitudinal expansions of the electrochemical cells 104 and 108 connected to one another by the cell connector 100, a change in the relative positions between the interconnected cell terminals 102 and 106 along the contact direction 128 of the cell terminals 102, 106 may occur.

[0110] In order to be able to compensate for such relative movements between the interconnected cell terminals 102, 106 and thus between the first contact region 116 and the second contact region 118 of the cell connector 100 in the longitudinal direction 134 of the cell connector 100, in the transverse direction 132 of the cell connector 100 and / or in the contact direction 128 of the cell connector 100 aligned parallel to the contact direction 128 of the cell terminals 102, 106, the base body 114 of the cell connector 100 comprises an elastically and / or plastically deformable connecting region 136, which is arranged between the first contact region 116 and the second contact region 118 in the current path of the cell connector 100 and connects the two contact regions 116 and 118 to one another. In the embodiment shown in Fig.In the embodiment of a cell connector 100 shown in Figures 1 and 2, the deformable connecting region 136 comprises, as an elastically and / or plastically deformable compensation element 138, a shaft 140 whose wave crest 142 extends parallel to the transverse direction 132 of the cell connector 100.

[0111] Furthermore, the cell connector in the current path between the first contact region 112 and the second contact region 114 preferably comprises at least one, particularly preferably several, in the illustrated embodiment two, cross-section-reduced regions 144, in which the electrically conductive cross-section of the cell connector 100 is reduced by at least one or preferably by several, in the illustrated embodiment by eleven, recesses 146.

[0112] The recesses 146 are preferably formed as through-openings 148 in the base body 114 of the cell connector 100 and extend from a bottom side 150 of the base body 114, which in the assembled state of the cell connector 100 faces the cell terminals 102, 106 to be connected to one another, to a top side 152 of the base body 114, which in the assembled state of the cell connector 100 faces away from the cell terminals 102, 106 to be connected to one another, through the entire base body 114 of the cell connector 100.

[0113] The recesses 146 or through-openings 148 follow one another along a perforation line 154 of the respective reduced-cross-section region 144 and are separated from an adjacent other recess 146 or through-opening 148 or from an edge of the base body 114 of the cell connector 100 by a constriction of the reduced-cross-section region 144.

[0114] Preferably, at least one of the through-openings 148 of the reduced-cross-section region 144 is formed as a circular hole 156. Particularly preferably, all through-openings 148 of the reduced-cross-section region 144 are each formed as a circular hole 156.

[0115] In principle, the passage openings 148 of the reduced-cross-section region 144 can also have a different shape, for example the shape of an elongated hole.

[0116] However, a through-opening 148 designed as a circular hole 156 is less likely to tear out when the cell connector 100 is subjected to alternating mechanical stress than a through-opening designed as an elongated hole.

[0117] The electrically conductive cross section of each reduced-cross-section region 144 is preferably less than half, in particular less than a third, particularly preferably less than a quarter, of the electrically conductive cross section that the respective reduced-cross-section region 144 would have without the presence of the recesses 146.

[0118] Furthermore, the electrically conductive cross-section of each reduced-cross-section region 144 of the cell connector 100 is preferably less than half, in particular less than a third, particularly preferably less than a quarter, of the electrically conductive cross-section of a region 158 of the cell connector 100 adjoining the respective reduced-cross-section region 144 in the current path between the first contact region 116 and the second contact region 118 of the cell connector 100.

[0119] In the embodiment of a cell connector 100 shown in Figs. 1 and 2, the cell connector 100 has a plurality of, for example two, cross-sectionally reduced regions 144 spaced apart from one another in the longitudinal direction 134 of the cell connector 100 in the current path between the first contact region 116 and the second contact region 118 of the cell connector 100. In particular, it can be provided that a first cross-section-reduced region 144a is arranged in a first flank 160a of the compensation element 138 of the connecting region 136, which is designed as a shaft 140, for example, and faces the first contact region 112 of the cell connector 100, and / or a second cross-section-reduced region 144b is arranged in a second flank 160b of the compensation element 138 of the connecting region 136, which is designed as a shaft 140, for example, and faces the second contact region 118 of the cell connector 100.

[0120] The base body 114 of the cell connector 100 is preferably formed from a material having a thermal conductivity of at least 200 W / mK and / or a specific heat capacity of at least 800 J / kgK.

[0121] The work-hardened aluminum materials described above exhibit these properties.

[0122] The base body 114 of the cell connector 100 is preferably separated from a flat starting material, for example by punching or cutting, for example laser cutting.

[0123] Subsequently, the starting material is brought into the final shape of the base body 114 by a forming process, for example a deep-drawing process and / or a stamping process, wherein the at least one compensation element 138 of the connecting region 136 is formed by forming.

[0124] The work hardening of the metallic starting material of the cell connector 100 can generally be carried out before, during, or after the forming process by which the at least one compensation element 138 of the connecting region 136 is formed. Likewise, the cutting out of the through-openings 148 of the reduced-cross-section regions 144 can generally be carried out before or after the forming process by which the at least one compensation element 138 of the connecting region 136 is formed.

[0125] The passage openings 148 are preferably separated from the material of the base body 114, for example punched out or cut out, preferably by means of a laser.

[0126] The recesses 146 or through-openings 148 preferably have a rounded edge in order to prevent tearing of the base body 114 after the recesses 146 or through-openings 148 have been produced in the base body 114.

[0127] Due to the small extent of the recesses 146 or through-openings 148 in the longitudinal direction 134 or in the connection direction 130 of the cell connector 100, the electrical resistance of the current path of the cell connector 100 from the first contact region 116 to the second contact region 118 is only slightly increased by the cross-section-reduced regions 144.

[0128] However, the thermal conductivity of the cell connector 100 is greatly reduced by the cross-sectional reduction in the area of ​​the cross-sectionally reduced regions 144 of the cell connector 100.

[0129] The mechanical properties of the connection region 136 of the cell connector 100, which serve to compensate for positional tolerances between the first contact region 116 and the second contact region 118, are retained. Because the strong cross-sectional reduction in the reduced-cross-section regions 144 only acts over a very short distance along the connection direction 130 for the electrical current flowing between the first contact region 116 and the second contact region 118 of the cell connector 100, the increase in the electrical resistance of the cell connector 100 is only slight, preferably less than 10%.

[0130] However, the reduction in cross-section in the reduced-cross-section regions 144 represents a significant obstacle to the transfer of heat, so that the thermal resistance of the cell connector 100 in the longitudinal direction 134 or in the connection direction 130 increases by preferably at least 200%.

[0131] Due to this significant increase in the thermal resistance of the cell connector 100, the propagation of a temperature increase from the first electrochemical cell 104 to the second electrochemical cell 108 is significantly delayed, preferably by at least 10 seconds, in particular by at least 15 seconds, particularly preferably by at least 20 seconds.

[0132] This prevents a thermal runaway (heating due to a malfunction of an electrochemical cell) of the first electrochemical cell 104 from also triggering a thermal runaway of the second electrochemical cell 108 due to heat transfer via the cell connector 100.

[0133] The work hardening of the material in the region of the at least one compensation element 138 of the connecting region 136 of the cell connector 100 results in the use of a smaller material thickness, in particular a smaller sheet thickness of the starting material, while maintaining the same modulus of elasticity. This leads to greater flexibility of the at least one compensation element 138 in the connecting region 136 and to lower rigidity thereof.

[0134] Due to the increased flexibility of the connecting region 136 as a result of the material used to form the at least one compensation element 138, the forces acting on the connection point, for example a weld seam, between a respective cell terminal 102, 106 on the one hand and the cell connector 100 on the other hand during operation of the electrochemical device are reduced, thereby increasing the service life of the connection point.

[0135] Furthermore, the work-hardened material from which the at least one compensation element 138 is formed has an increased tensile strength and an increased fatigue strength.

[0136] This has a positive effect on the operational strength of the connection region 136 of the cell connector 100 during operation of the electrochemical device 112.

[0137] As already mentioned, the starting material for the production of the work-hardened metallic material is preferably a soft-annealed sheet (in the Hill condition), which is hardened by the work-hardening process, for example a cold rolling process or a stamping process, optionally to one of the conditions H12, H14, H16 or H18.

[0138] Since the at least one compensation element 138 made of the work-hardened material has a higher fatigue strength, the shape and number of the compensation elements 138 can be adapted accordingly.

[0139] If the connecting region 136 comprises a plurality of corrugations 140 as compensation elements 138, the number of corrugations can be reduced. If the connecting region 136 has at least one corrugation 140 and / or at least one half-bead as compensation element 138, the height of the corrugation 140 or the half-bead, i.e., their extension along the contact direction 128 of the cell connector 100, can be reduced, which leads to a reduction in the required installation space for the cell contact system in the contact direction 128.

[0140] If the connecting region 136 has at least one plateau which is arranged between two waves 140, between two half-beads or between a wave 140 and a half-bead, the length of the plateau, i.e. its extension in the longitudinal direction 134 of the cell connector 100, can be reduced due to the work hardening of the material from which the connecting region 136 is formed.

[0141] If the connecting region 136 has bent regions with a bending radius, these bent regions can be designed with smaller bending radii due to the work hardening of the material from which these bent regions are formed.

[0142] All this leads to a reduction in the installation space required for the arrangement of the cell contact system.

[0143] It is preferably provided that the material thickness of the base body 114 of the cell connector 100 is mechanically reduced in the region of at least one compensation element 138 of the connecting region 136, for example by stamping, in order to cold harden the material of the respective compensation element 138.

[0144] The work-hardened compensation element 138 can, for example, be a wave 140, a half-bead, or a bead. The material of the base body 114 of the cell connector 100 can also be work-hardened at least in sections in the first contact region 116 and / or in the second contact region 118 of the cell connector 100 and therefore have a lower material thickness, since contact regions 116, 118 with a lower material thickness, i.e., with a smaller extension along the contact direction 128, are easier to weld and thus easier to connect to the respectively associated cell terminal 102, 106.

[0145] Cold hardening, particularly through stamping, increases the flexibility and fatigue strength of the cell connector 100 while requiring less space.

[0146] In the embodiment of a cell connector 100 shown in Figs. 1 and 2, the entire material of the base body 114 is work hardened.

[0147] 4 and 5 show a section of a second embodiment of a cell connector 100, in which a first contact region 116 made of a work-hardened material is connected to a web region 162 made of a non-work-hardened material via a connecting region 136 made of a work-hardened material.

[0148] At least one second contact region 118 (not shown) is connected to the web region 162 via a further connection region 136 (not shown).

[0149] As can best be seen from the longitudinal section through the first contact region 116, the connection region 136 and the web region 162 of the cell connector 100 from Fig. 4 in Fig. 5, the material thickness hi of the base body 114 of the cell connector 100 in the first contact region 116 and in the connection region 136 is significantly less than the material thickness ho of the base body 114 of the cell connector 100 in the web region 162 of the cell connector 100. For example, it can be provided that the material thickness hi is approximately 50% of the material thickness ho.

[0150] The embossing of the material of the first contact region 116 and the connecting region 136 to the lower material thickness hi can be carried out before, during or after the formation of the compensation element 138 in the connecting region 136 by a forming process.

[0151] In the embodiment shown in Figs. 4 and 5, the connecting region 136 comprises a shaft 140 as an elastically and / or plastically deformable compensation element 138.

[0152] However, the connecting region 136 could also comprise a half-bead instead of a wave 140, or the connecting region 136 could comprise a plurality of compensation elements 138, for example a plurality of waves 140, a plurality of half-beads or at least one wave 140 and at least one half-bead.

[0153] Various embodiments showing how a connecting region 136 formed from a work-hardened material can be formed from one or more compensation elements 138 are shown in Figs. 6 to 12, each in a longitudinal section along the connecting direction 130 through a connecting region 136.

[0154] Fig. 6 shows an embodiment of a cell connector 100 in which the connecting region 136 arranged between a first contact region 116 and a second contact region 118 comprises a shaft 140 as a compensation element 138.

[0155] Fig. 7 shows an embodiment of a cell connector 100 in which the connecting region 136 arranged between a first contact region 116 and a second contact region 118 comprises a half-bead 164 as a compensation element 138. The half-bead 164 has a substantially S-shaped or Z-shaped cross-section.

[0156] In the embodiment of a cell connector 100 shown in Fig. 8, the connecting region 136 arranged between a first contact region 116 and a second contact region 118 comprises, as compensation elements 138, a first half-bead 164a, which adjoins the first contact region 116, and a second half-bead 164b, which adjoins the second contact region 118.

[0157] In the embodiment of a cell connector 100 shown in Fig. 9, the connecting region 136 arranged between a first contact region 116 and a second contact region 118 comprises, as compensation elements 138, a first half-bead 164a which adjoins the first contact region 116, a second half-bead 164b which adjoins the first half-bead 164a, a third half-bead 164c which adjoins the second half-bead 164b, and a fourth half-bead 164d which adjoins the second contact region 118.

[0158] All four half beads 164a to 164d each have a substantially S-shaped or Z-shaped cross-section.

[0159] An embodiment of a cell connector 100 shown in Fig. 10 differs from the embodiment shown in Fig. 8 in that a plateau 166 is arranged between the two half-beads 164a and 164b, which the connecting region 136 comprises as elastically and / or plastically deformable compensation elements 138. This plateau connects the first half-bead 164a and the second half-bead 164b to one another. The plateau 166 is essentially flat and aligned essentially parallel to the first contact region 116 and essentially parallel to the second contact region 118 of the cell connector 100, but is offset in the contacting direction 128 from both the first contact region 116 and the second contact region 118.

[0160] As can be seen from Fig. 10, the plateau 166 between the first half-bead 164a and the second half-bead 164b has a length li along the connecting direction 130.

[0161] Furthermore, the plateau 166 has an offset vi relative to the first contact region 116 of the cell connector 100 along the contacting direction 128.

[0162] An embodiment of a cell connector 100 shown in Fig. 11 differs from the embodiment shown in Fig. 10 in that the length of the plateau 166 in the embodiment of Fig. 11 is greater than the length li of the plateau 166 along the connection direction 130 in the embodiment shown in Fig. 10.

[0163] The offset vi of the plateau 166 relative to the first contact region 116 along the contacting direction 128, however, is the same in the two embodiments according to Figs. 10 and 11.

[0164] A further embodiment of a cell connector 100 shown in Fig. 12 differs from the embodiment shown in Fig. 10 in that the offset V2 of the plateau 166 relative to the first contact region 116 in the embodiment shown in Fig. 12 is greater than the offset vi of the plateau 166 relative to the first contact region 116 along the contacting direction 128 in the embodiment shown in Fig. 10. In contrast, the length li of the plateau 166 along the connecting direction 130 in the embodiment of a cell connector 100 shown in Fig. 12 is essentially the same as the length li of the plateau 166 along the connecting direction 130 in the embodiment of a cell connector 100 shown in Fig. 10.

[0165] Of course, an embodiment of a cell connector could also be created in which both the offset of the plateau 166 relative to the first contact region 116 along the contacting direction 128 and the length of the plateau 166 along the connecting direction 130 are different from the corresponding dimensions of the cell connector 100 shown in Fig. 10.

Claims

Patent claims 1. Cell connector for the electrically conductive connection of at least one first cell terminal (102) of a first electrochemical cell (104) and at least one second cell terminal (106) of a second electrochemical cell (108), comprising at least one first contact region (116) for the electrically conductive connection of the cell connector (100) to the at least one first cell terminal (102), at least one second contact region (118) for the electrically conductive connection of the cell connector (100) to the at least one second cell terminal (106), and at least one elastically and / or plastically deformable connecting region (136) which is arranged in the current path between the at least one first contact region (116) and the at least one second contact region (118), characterized in that the connecting region (136) is formed at least partially from a work-hardened metallic material.

2. Cell connector according to claim 1, characterized in that the work-hardened metallic material is an aluminum material or a copper material.

3. Cell connector according to one of claims 1 or 2, characterized in that the degree of deformation (s) of the work-hardened metallic material is at least 10%.

4. Cell connector according to one of claims 1 to 3, characterized in that the tensile strength (Rm) of the work-hardened metallic material is more than 90 N / mm 2 amounts.

5. Cell connector according to one of claims 1 to 4, characterized in that the work-hardened metallic material is work-hardened by a cold rolling process, a stamping process or a forming process with local reduction of the material thickness.

6. Cell connector according to one of claims 1 to 5, characterized in that the cell connector (100) is formed in a single layer at least in the connecting region (136).

7. Cell connector according to one of claims 1 to 6, characterized in that the connecting region (136) is formed substantially entirely from the work-hardened metallic material.

8. Cell connector according to one of claims 1 to 7, characterized in that the connecting region (136) has at least one elastically and / or plastically deformable compensation element (138) made of the work-hardened material.

9. Cell connector according to claim 8, characterized in that the connecting region (136) comprises at least one wave (140), a step, a plateau (166) and / or a half-bead (164).

10. Cell connector according to one of claims 1 to 9, characterized in that the cell connector (100) has at least one cross-section-reduced region (144) in the current path between the at least one first contact region (116) and the at least one second contact region (118), in which the electrically conductive cross-section of the cell connector (100) is reduced by at least one recess (146).

11. Cell connector according to one of claims 1 to 10, characterized in that the at least one first contact region (116) and / or the at least one second contact region (118) of the cell connector (100) is at least partially formed from a work-hardened metallic material.

12. Cell contacting system for an electrochemical device (112) comprising a plurality of electrochemical cells (104, 108), comprising at least one cell connector (100) according to one of claims 1 to 11.

13. An electrochemical device comprising a plurality of electrochemical cells (104, 108) and a cell contacting system according to claim 12.

14. A method for producing a cell connector (100) for electrically connecting at least one first cell terminal (102) of a first electrochemical cell (104) and at least one second cell terminal (106) of a second electrochemical cell (108), wherein the cell connector (100) comprises at least one first contact region (116) for electrically connecting the cell connector (100) to the at least one first cell terminal (102), at least one second contact region (118) for electrically connecting the cell connector (100) to the at least one second cell terminal (106), and at least one elastically and / or plastically deformable connecting region (136) arranged in the current path between the at least one first contact region (116) and the at least one second contact region (118), the method comprising the following: Providing a metallic starting material; Work hardening at least a portion of the metallic starting material to form a work hardened metallic material; and Formation of at least the at least one connection region (136) of the cell connector (100) by forming the work-hardened metallic material or during the work-hardening of the metallic starting material to form the work-hardened metallic material.

15. A method according to claim 14, characterized in that the metallic starting material is soft annealed before work hardening.

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