Electrochemical device and method for electrically connecting two cell terminals of electrochemical cells of an electrochemical device

Abstract

Electrochemical device comprising at least a first electrochemical cell (104) with a first cell terminal (134), a second electrochemical cell (104) with a second cell terminal (136), and a cell connector (132) electrically connecting the first cell terminal (134) and the second cell terminal (136), wherein the cell connector (132) comprises a first contact section (154) for connecting to the first cell terminal (134), a second contact section (156) for connecting to the second cell terminal (136), and an elastically and / or plastically deformable compensation area (206) that connects the first contact section (154) and the second contact section (156) and allows movement of these contact sections (154, 156) relative to each other.wherein the electrochemical device (100) comprises a receiving device (108) with at least a first receiving for the first electrochemical cell (104) and a second receiving for the second electrochemical cell (104), wherein the cell connector (132) comprises a base body (152) formed from a material having a coefficient of thermal expansion α that differs by less than 10% from the coefficient of thermal expansion α of the material of the receiving device (108), and wherein the receiving device (108) is configured as a heat sink (110) which is in thermally conductive contact with the electrochemical cells (104) received therein.

Description

The present invention relates to an electrochemical device comprising at least a first electrochemical cell with a first cell terminal, a second electrochemical cell with a second cell terminal and a cell connector electrically connecting the first cell terminal and the second cell terminal. Such electrochemical devices can be designed in particular as electrical accumulators, for example as lithium-ion accumulators. In a lithium-ion battery, the voltage difference between the two cell terminals (poles) of a single battery cell is approximately 3.6 V. To obtain a higher voltage level of, for example, approximately 360 V, which is required for many applications, such as in automotive drive technology, many such battery cells (for example, approximately 100) must be electrically connected in series. The accumulator cells, or electrochemical cells in general, can be grouped into modules, each containing several such electrochemical cells, with the installation direction of adjacent cells alternating so that positive and negative cell terminals alternate next to each other. These adjacent cell terminals of opposite polarity are directly connected to each other for series connection of the cells by means of a cell connector each. WO 2008 / 098193 A2, US 2004 / 0 166 727 A1 and WO 2009 / 041 735 A1 disclose electrochemical devices comprising at least a first electrochemical cell with a first cell terminal, a second electrochemical cell with a second cell terminal and a cell connector electrically connecting the first cell terminal and the second cell terminal, wherein the cell connector comprises a first contact section for connecting to the first cell terminal, a second contact section for connecting to the second cell terminal and an elastically and / or plastically deformable compensation area connecting the first contact section and the second contact section and allowing movement of these contact sections relative to each other. US Patent 3,537,907 A discloses a small battery consisting of four nickel-cadmium cells mounted in grooves of an aluminum heat sink provided with an electrically insulating layer. The cell connectors of the battery described in this patent are made of nickel, which has a coefficient of thermal expansion more than 43% lower than that of aluminum. US Patent 2007 / 0 020 513 A1 discloses various embodiments of electrochemical devices. In some of these embodiments, the electrochemical cells are held apart from one another by separators made of an electrically insulating plastic material. In other embodiments of an electrochemical device from this document, the electrochemical cells are arranged between the separator rods, with the interconnected cell terminals of two electrochemical cells arranged successively in a longitudinal direction of the electrochemical device being supported against the cooling separator rods by means of a connecting disk. The cooling separator rods are made of aluminum but are not in direct thermal contact with the electrochemical cells accommodated between them.In all embodiments of electrochemical devices from this publication, the negative terminal and the positive terminal of the electrochemical cells are arranged on opposite end faces of the respective cylindrical electrochemical cell. The present invention is based on the objective of creating an electrochemical device of the type mentioned above in which a reliable and operationally safe connection of the cell terminals is enabled. This problem is solved by an electrochemical device according to claim 1. The elastic and / or plastically deformable compensation area, by allowing the two contact sections of the cell connector to move relative to each other, serves to at least partially compensate a) a difference between a longitudinal strain of the cell connector on the one hand and a change in the distance between the longitudinal axes of the cell terminals connected by the cell connector on the other hand and / or b) a difference between a longitudinal strain of the first electrochemical cell on the one hand and a longitudinal strain of the second electrochemical cell on the other. In addition, the elastically and / or plastically deformable compensation area can also serve to at least partially compensate for differences in the positions of the cell terminals to be connected, which are based on manufacturing tolerances, especially in the axial direction of the electrochemical cells. In a preferred embodiment of the invention, the compensation area allows movement of the contact sections relative to each other in a longitudinal direction of the cell connector, which in the assembled state of the cell connector is oriented transversely, preferably essentially perpendicularly, to the axial direction of the electrochemical cells to be connected. Alternatively or additionally, the compensation area may be designed to allow movement of the contact sections relative to each other in a contact direction of the cell connector, which in the assembled state of the cell connector is essentially parallel to the axial direction of the electrochemical cells to be connected. The compensation area is preferably arranged between the first contact section and the second contact section of the cell connector. In order to enable the desired relative movement between the two contact sections of the cell connector, the compensation area is preferably provided with a profile, in particular with a wave structure and / or a zigzag structure and / or a beaded structure. In particular, it may be provided that the compensation area of ​​the cell connector has at least one wave or bead or kink line running transversely, preferably substantially perpendicularly, to the longitudinal direction of the cell connector. The groove can be designed as a full groove or as a half groove. In preferred embodiments of the electrochemical device, the compensation area of ​​the cell connector has several wave crests and / or wave troughs or several beads or several bend lines extending in this direction, preferably substantially perpendicular to the longitudinal direction of the cell connector, thereby increasing the deformability of the compensation area and the mobility of the contact sections relative to each other. Furthermore, it can be provided that the compensation area of ​​the cell connector comprises at least one, preferably wave-shaped, bridge. Such a bridge can, in particular, connect the first contact section of the cell connector and the second contact section of the cell connector. Preferably, several such bridges are arranged next to each other. Furthermore, it may be provided that the cell connector comprises two or more layers of material that are laminated together. In order to enable the coupling of a voltage measuring device to the cell connector and thus the cell terminals connected to each other via the cell connector, it is advantageous if the cell connector has at least one, preferably web-shaped, voltage tap. In order to ensure that, after at least partial compensation of the positional differences between the cell terminals to be connected, only low mechanical stresses and restoring forces are exerted on the cell terminals by the cell connector, it is advantageous if the compensation area of ​​the cell connector is made of a material with a yield strength R of at most 60 N / mm2, preferably of at most 40 N / mm2, and in particular of at most 20 N / mm2. Preferably, the compensation area is made of aluminum or an aluminum alloy. The electrochemical device comprises a receiving device with at least one first receptacle for the first electrochemical cell and a second receptacle for the second electrochemical cell. To reduce mechanical stresses occurring during operation of the electrochemical device, which can arise from differing thermal expansions of the cell connector on the one hand and the receiving device for the electrochemical cells on the other, it is advantageous for the cell connector to comprise a base body made of a material having a coefficient of thermal expansion α that differs by less than 10% from the coefficient of thermal expansion α of the receiving device material. If the coefficients of thermal expansion of these materials vary significantly from the ambient temperature to the operating temperature of the electrochemical device, this specification refers to the respective average coefficients of thermal expansion when heated from the ambient temperature (20°C) to the operating temperature of the electrochemical device (which is, for example, 60°C). To avoid such mechanical stresses, it is particularly advantageous if the material of the base body and the material of the receiving device are essentially the same. In particular, it may be provided that the material of the base body and the material of the receiving device are aluminium or an aluminium alloy. The electrochemical device can in particular be designed as an accumulator, especially as a lithium-ion accumulator. The present invention further relates to a method for electrically connecting a first cell terminal of a first electrochemical cell to a second cell terminal of a second electrochemical cell of an electrochemical device. The present invention is based on the further objective of creating a method by which a reliable and operationally safe connection of the cell terminals is achieved. This problem is solved according to the invention by a method for electrically connecting a first cell terminal of a first electrochemical cell with a second cell terminal of a second electrochemical cell of an electrochemical device according to claim 9. The connection of the cell connector to the cell terminals is preferably achieved by material bonding. To reduce the mechanical stresses occurring at the connection points between the cell connector and the cell terminals to be connected, it can be provided that the cell connector is deformed, preferably plastically, before being connected to the first cell terminal and / or before being connected to the second cell terminal, such that the first contact section of the cell connector to be connected to the first cell terminal and the second contact section of the cell connector to be connected to the second cell terminal are displaced relative to each other in such a way that differences in the positions of the first cell terminal and the second cell terminal in the axial direction of the first electrochemical cell and the second electrochemical cell are at least partially, preferably substantially completely, compensated. It is particularly advantageous if the relative position of the first cell terminal and the second cell terminal in the axial direction of the first electrochemical cell and the second electrochemical cell is measured before the cell connector is deformed, so that the subsequent reshaping of the cell connector, especially the compensation area of ​​the cell connector, can be carried out in a targeted manner. Furthermore, the yield strength of at least part of the cell connector material can be reduced by heat treatment before and / or during the connection of the cell connector with the first cell terminal or with the second cell terminal; by such a reduction of the yield strength of the material through heat treatment, the mechanical stresses at the connection point during and / or after the metallurgical connection of the cell connector with the first cell terminal or with the second cell terminal can be reduced. The cell connector of the electrochemical device according to the invention can utilize the synergies of different materials and reduces or overcomes the disadvantages that are characteristic of known connection types of such cell connectors. The cell connector exhibits low electrical volume resistance and low contact resistances at the transitions between the cell terminals and the cell connector. Furthermore, the cell connector has a low mass and good handling characteristics and can be manufactured at low cost. The cell connector can be manufactured using established manufacturing processes and reliably connected to the cell terminals using process-reliable methods. The type of connection between the cell connector and the cell terminals ensures good corrosion protection for all components involved. Special embodiments of the cell connector and the electrochemical device according to the invention offer the advantages that a length compensation for compensating relative movements of the cell terminals relative to each other and / or a compensation for differences in the positions of the cell terminals along the axial direction of the cells caused by manufacturing tolerances or by different thermal length changes of the electrochemical cells are integrated into the cell connector. If a length compensation field is integrated into the cell connector, the cells connected by the cell connector are protected and their longevity is promoted. Furthermore, at least one voltage tap for individual cell monitoring can be integrated into the cell connector. This allows a voltage measuring device to be easily connected to each cell connector. Multiple cell connectors can be manufactured together in a single, integrated connector assembly, for example as stamped and bent parts, and then handled together until they are attached to their respective cell terminals. This significantly speeds up the assembly of the electrochemical device, as the cell connectors no longer need to be individually fed to the cell terminals to be connected. This considerably reduces handling costs. A modular design of the cell connectors results in process improvement. The present invention enables the production of cost-effective, reliable connecting elements for connecting individual electrochemical cells with high power density and short charging and discharging cycles. The cell connector creates the shortest possible and least lossy direct connection between any two electrochemical cells. The conductivity of the cell connector meets high standards, especially when the cell terminals are welded or soldered to the cell connector using a single-material weld. If the electrochemical device according to the invention is designed as an accumulator, it is particularly suitable as a high-capacity energy source, for example for powering motor vehicles. Further features and advantages of the invention are the subject of the following description and the graphic representation of exemplary embodiments. The drawings show: Fig. 1 a schematic perspective view of a module of an electrochemical device, comprising several, for example eight, electrochemical cells, a holding device for the cells, several cell connectors for electrically connecting the cell terminals of two electrochemical cells each, a circuit board for tapping the voltage from the cell connectors, and electrical connections for electrically connecting the module to other modules, to a charging device, or to a load; Fig. 2 a top view of a front view of the module from Fig. 1; Fig. 3 a schematic perspective view of the module corresponding to Fig. 1 without the holding device; Fig. 4 a schematic side view of the module without the holding device from Fig. 3; Fig. 5 a schematic top view of the circuit board of the module from Figs. 1, 2, 3 to 4; Fig.Fig. 6 a schematic top view of the front cell terminals of the module's electrochemical cells; Fig. 7 a top view corresponding to Fig. 6 of the front cell terminals of the electrochemical cells and a support frame in which the electrochemical cells are held; Fig. 8 a schematic top view of a group of cell connectors that are cut together from a starting material and connected to each other by connecting webs; Fig. 9 a schematic top view of the module's front cell terminals with the cell connectors of the cell connector group from Fig. 8 attached to the cell terminals, the connecting webs between the cell connectors still present; Fig. 10 a schematic top view of the module's front cell terminals and the cell connectors attached to them after the connecting webs between the cell connectors of the cell connector group have been removed; Fig.Fig. 11 a schematic section through two electrochemical cells and a cell connector with a base body, which is directly welded to a first cell terminal and indirectly welded to a second cell terminal via a contact area, wherein the contact area is connected to the base body by ultrasonic welding; Fig. 12 a schematic section through two electrochemical cells and a cell connector, which is directly welded to a first cell terminal and indirectly welded to a second cell terminal via a contact area, wherein the contact area is connected to the base body by laser welding along a weld seam; Fig. 13 a schematic section through two electrochemical cells and a cell connector, which is connected to a first cell terminal by welding and to a second cell terminal by soldering; Fig.Figure 14 shows a schematic top view of a cell connector having a deformable compensation area with a wave structure, wherein the wave structure has an amplitude directed parallel to the axial direction of the electrochemical cells and several, for example four, wave crests extending transversely to the axial direction of the electrochemical cells and several, for example three, wave troughs extending transversely to the axial direction of the electrochemical cells, and wherein the cell connector further comprises retaining webs for connecting the cell connector to the circuit board of the module; Figure 15 shows a schematic side view of the cell connector from Figure 14; Figure 16 shows a schematic side view of the cell connector from Figure 14 and the two electrochemical cells connected to each other by means of the cell connector; FigureFig. 17 a schematic top view of an alternative embodiment of a cell connector having a deformable compensation area comprising a wave structure, wherein the wave structure has an amplitude in the axial direction of the electrochemical cells and several, for example three, wave crests extending transversely to the axial direction of the electrochemical cells and several, for example two, wave troughs extending transversely to the axial direction of the electrochemical cells, and wherein the cell connector furthermore has no retaining webs; Fig. 18 a schematic side view of the cell connector from Fig. 17; Fig. 19 a schematic top view of an alternative embodiment of a cell connector with a deformable compensation area having a half-ribbed structure that transitions into contact areas of the cell connector at bend lines; Fig. 20 a schematic side view of the cell connector from Fig. 19; Fig.21 a schematic top view of an alternative embodiment of a cell connector with a deformable compensation area having a wave structure, wherein the wave structure has an amplitude in the axial direction of the electrochemical cells and comprises a wave crest extending transversely to the axial direction of the electrochemical cells and a wave trough extending transversely to the axial direction of the electrochemical cells; Fig. 22 a schematic side view of the cell connector from Fig. 21; Fig.23 A schematic top view of an alternative embodiment of a cell connector with a deformable compensation area, which has a wave structure, wherein the wave structure has an amplitude in the axial direction of the electrochemical cells and comprises several, for example two, wave crests extending transversely to the axial direction of the electrochemical cells and a wave trough extending transversely to the axial direction of the electrochemical cells; Fig. 24 A schematic side view of the cell connector from Fig. 23; Fig. 25 A schematic top view of an alternative embodiment of a cell connector with a deformable compensation area, which has a zigzag structure, wherein the zigzag structure has several, for example five, bend lines extending transversely to the axial direction of the electrochemical cells; Fig. 26 A schematic side view of the cell connector from Fig. 25; Fig.27 a schematic top view of an alternative embodiment of a cell connector with a deformable compensation area, which has a wave structure, wherein the wave structure has an amplitude in the axial direction of the electrochemical cells and comprises several, for example three, wave crests extending transversely to the axial direction of the electrochemical cells and several, for example two, wave troughs extending transversely to the axial direction of the electrochemical cells; Fig. 28 a schematic side view of the cell connector from Fig. 27; Fig.29 A schematic top view of an alternative embodiment of a cell connector with a deformable compensation area having a wave structure, wherein the wave structure has an amplitude in the axial direction of the electrochemical cells and comprises several, for example four, wave crests extending transversely to the axial direction of the electrochemical cells and several, for example three, wave troughs extending transversely to the axial direction of the electrochemical cells; Fig. 30 A schematic side view of the cell connector from Fig. 29; Fig.31 A schematic top view of an alternative embodiment of a cell connector with a deformable compensation area, which has a wave structure, wherein the wave structure has an amplitude in the axial direction of the electrochemical cells and comprises several, for example three, wave crests extending transversely to the axial direction of the electrochemical cells and several, for example two, wave troughs extending transversely to the axial direction of the electrochemical cells, wherein a base body of the cell connector is formed as a laminate of several, for example three, superimposed layers or material layers; Fig. 32 A schematic side view of the cell connector from Fig. 31; Fig. 33 An enlarged view of area A from Fig. 32; Fig.34 A schematic top view of an alternative embodiment of a cell connector with a deformable compensation area, which has a wave structure, wherein the wave structure has an amplitude in the axial direction of the electrochemical cells and comprises several, for example three, wave crests extending transversely to the axial direction of the electrochemical cells and several, for example two, wave troughs extending transversely to the axial direction of the electrochemical cells, and wherein the compensation area is divided by several, for example three, wave-shaped slots into several, for example four, wave-shaped ribs, which are arranged next to each other in a direction transverse to the axial direction of the electrochemical cells, wherein the wave shape of the slots and the wave shape of the ribs have an amplitude transverse to the axial direction of the electrochemical cells; Fig. 35 A schematic side view of the cell connector from Fig.34; Fig. 36 a schematic top view of an alternative embodiment of a cell connector with a deformable compensation area, which is essentially planar but is subdivided by several, for example three, wave-shaped slots into several, for example four, wave-shaped webs, wherein the wave shape of the slots and the wave shape of the webs have an amplitude transverse to the axial direction of the electrochemical cells; Fig. 37 a schematic side view of the cell connector from Fig. 36; Fig. 38 a schematic top view of several cell connectors, each formed integrally with a conductor track for a voltage tap from the cell connectors; Fig. 39 a schematic side view of the cell connector assembly from Fig. 38, wherein the cell connectors are arranged at the cell terminals of the electrochemical cells of the module; Fig.Fig. 40 is a schematic perspective view of two modules of the electrochemical device, wherein an electrical connection of a first module is connected to an electrical connection of a second module via a module connector; Fig. 41 is a schematic side view of the two modules with the module connector from Fig. 40, looking at one narrow side of the modules; Fig. 42 is a schematic longitudinal section through the two modules and the module connector from Fig. 41, along line 42-42 in Fig. 41; Fig. 43 is a schematic perspective view of the module connector from Figs. 40, 41 to 42, seen from the side facing the electrical connections of the modules; Fig. 44 is a schematic perspective view of the module connector from Figs. 40, 41 to 42, seen from the side facing away from the electrical connections of the modules; Fig. 45 is a schematic side view of the module connector from Figs. 43 and 44; Fig.46 a schematic top view of the module connector from Figs. 43, 44 to 45, showing the side of the module connector facing away from the electrical connections of the modules; Fig. 47 a schematic top view of a specimen for determining the corrosion resistance of a weld between a cell terminal and a cell connector; Fig. 48 a schematic side view of the specimen from Fig. 47; Fig. 49 a schematic longitudinal section through the specimen from Figs. 47 and 48; Fig. 50 a schematic top view of an auxiliary frame for holding cell connectors; and Fig. 51 a schematic top view of a module support frame with a connector assembly held thereon. Identical or functionally equivalent elements are designated with the same reference symbols in all figures. An electrochemical device designated as a whole by 100 comprises several electrochemical modules 102, one of which is shown as a whole in Figs. 1, 2, 3 to 4. Each of the modules 102 comprises several, for example eight, electrochemical cells 104, each of which is received in a receptacle of a receiving device 108 of the module 102. This receiving device 108 can in particular be designed as a heat sink 110 which is in thermally conductive contact with the electrochemical cells 104 received therein in order to dissipate heat from the electrochemical cells 104 during the operation of the electrochemical device 100. The receiving device 108 is preferably made of a material that conducts heat well, for example aluminum or an aluminum alloy. As can best be seen from Figs. 3 and 4, which show the module 102 without the receiving device 108, the electrochemical cells 104 are arranged and aligned in the receiving device 108 surrounding them such that the axial directions 112 of the electrochemical cells 104, which run parallel to the central longitudinal axes 114 of the electrochemical cells 104, are essentially parallel to each other. As can best be seen from Fig. 4, each of the electrochemical cells 104 extends from a front cell terminal 116 (shown above in Fig. 4) in the respective axial direction 112 to a rear cell terminal 118 (shown below in Fig. 4), each cell terminal forming a positive pole or a negative pole of the electrochemical cell 104. The central longitudinal axes 114 of the electrochemical cells 104 are simultaneously central longitudinal axes of the cell terminals 116, 118 of the respective electrochemical cells 104. In module 102, adjacent electrochemical cells 104 are each oriented such that the cell terminals of two adjacent cells arranged on the same side of the module have opposite polarity. This is illustrated below with reference to Fig. 6, which shows the polarities of, for example, eight, front cell terminals 116 of the eight electrochemical cells 104 of a module 102. In this case, the front cell terminal 116 of the electrochemical cell 104a forms a positive pole of the electrochemical cell 104a in question, while the front cell terminal 116 of the electrochemical cell 104b adjacent in a first transverse direction 120 of the module 102 of the electrochemical cell 104a forms a negative pole of the electrochemical cell 104b. Accordingly, the front cell terminal 116 of the electrochemical cell 104c following the electrochemical cell 104b in the first transverse direction 120 forms a positive pole of the electrochemical cell 104c and the front cell terminal 116 of the electrochemical cell 104d following the electrochemical cell 104c in the first transverse direction 120 forms a negative pole of the electrochemical cell 104d. The front cell terminal 116 of module 102 of electrochemical cell 104e, which follows electrochemical cell 104d in a second transverse direction 122, which is oriented perpendicular to the first transverse direction 120 of module 102 and perpendicular to the axial directions 112 of electrochemical cells 104, forms a positive pole of electrochemical cell 104e. The front cell terminal 116 of the electrochemical cell 104f following the electrochemical cell 104e in the first transverse direction 120 forms a negative pole of the electrochemical cell 104f, while the front cell terminal 116 of the electrochemical cell 104g following the electrochemical cell 104f in the first transverse direction 120 forms a positive pole of the electrochemical cell 104g, and the front cell terminal 116 of the electrochemical cell 104h following the electrochemical cell 104g in the first transverse direction 120 finally forms a negative pole of the electrochemical cell 104h. If the anterior cell terminal 116 of an electrochemical cell 104 forms a positive pole of that electrochemical cell 104, then the posterior cell terminal 118 forms a negative pole of the same cell 104. If the anterior cell terminal 116 of an electrochemical cell 104 forms a negative pole of that electrochemical cell 104, then the posterior cell terminal 118 of the same electrochemical cell 104 forms a positive pole of the same electrochemical cell 104. The electrochemical device 100 can in particular be designed as an accumulator, in particular as a lithium-ion accumulator, for example of type LiFePO4. The electrochemical cells 104 of the electrochemical modules 102 can accordingly be designed as accumulator cells, in particular as lithium-ion accumulator cells, for example of the LiFePO4 type. As can be seen in particular from Fig. 3 and Fig. 4, the front ends of the electrochemical cells 104 with the front cell terminals 116 extend through a front support frame 124, which has a passage opening 126 for each electrochemical cell 104, and the rear ends of the electrochemical cells 104 with the rear cell terminals 118 extend through a rear support frame 128, which also has a passage opening 130 for each electrochemical cell 104. The holder frames 124 and 128 thus serve to position the electrochemical cells 104. The mounting frames 124 and 128 can be made of an electrically insulating material, for example, a plastic material. As can be seen in particular from the top view of Fig. 2, the electrochemical module 102 further comprises several cell connectors 132, by means of which the cell terminals of adjacent electrochemical cells 104 with different polarities are electrically connected to each other in order to connect all electrochemical cells 104 of the electrochemical module 102 electrically in series. Each cell connector 132 connects a first cell terminal 134 of positive polarity to a second cell terminal 136 of negative polarity of an adjacent electrochemical cell 104. As can be seen from Fig. 2, in particular the first cell terminal 134c of the electrochemical cell 104c and the second cell terminal 136b of the electrochemical cell 104b are connected to each other by a cell connector 132c, the first cell terminal 134e of the electrochemical cell 104e and the second cell terminal 136d of the electrochemical cell 104d are connected to each other by a cell connector 132e, and the first cell terminal 134g of the electrochemical cell 104g and the second cell terminal 136f of the electrochemical cell 104f are connected to each other by a cell connector 132g. To connect all electrochemical cells 104 of module 102 electrically in series, the rear cell terminals 118 of adjacent electrochemical cells 104 are also connected to each other by (not shown) cell connectors 132, namely the (negative) rear cell terminal 118 of electrochemical cell 104a to the (positive) rear cell terminal 118 of electrochemical cell 104b, the (negative) rear cell terminal 118 of electrochemical cell 104c to the (positive) rear cell terminal 118 of electrochemical cell 104d, the (negative) rear cell terminal 118 of electrochemical cell 104e to the (positive) rear cell terminal 118 of electrochemical cell 104f, and the (negative) rear cell terminal 118 of electrochemical cell 104g to the (positive) rear cell terminal 118 of electrochemical cell 104f. Cell terminal 118 of the electrochemical cell 104h. The front cell terminal 116 of the electrochemical cell 104a, which forms the beginning of the series connection of the electrochemical module 102, and the front cell terminal 116 of the electrochemical cell 104h, which forms the end of the series connection, are each electrically connected to an electrically conductive terminal 138 of the electrochemical module 102. Each of the electrical connections 138 comprises a contact element 140, for example designed as a stamped and bent part, with a contact section 142 which is fixed to the respective associated cell terminal, with a plug section 144, for example sword-shaped, which extends away from the contact section 142, for example in the first transverse direction 120 of the electrochemical module 102 and preferably perpendicular to the axial direction 112 of the electrochemical cells 104, and with a retaining web 146 which is narrow compared to the contact section 142 and the plug section 144, for example angle-shaped, which connects the contact element 140 to a holder 148 in the form of a printed circuit board 150 arranged on the front of the electrochemical module 102. An end of the retaining rib 146 facing away from the contact section 142 and the plug section 144 of the contact element 140 is electrically connected to a conductor track (not shown) on the back of the circuit board 150 facing the electrochemical cells 104. The retaining bridge 146 thus serves not only as a mechanical retaining element, but also as a voltage tap 151. Each of the cell connectors 132, which electrically connect a first cell terminal 134 and a second cell terminal 136, comprises a base body 152 with a first contact section 154, which in the assembled state of the cell connector 132 is connected to the (positive) first cell terminal 134 of an electrochemical cell 104, and a second contact section 156, which in the assembled state of the cell connector 132 is connected to a (negative) second cell terminal 136 of another electrochemical cell 104. The base body 132 of the cell connector 132 is preferably manufactured as a stamped and bent part. In the embodiment of a cell connector 132 shown in Figs. 2 and 8 to 10, the base body 152 of the cell connector 132 further comprises a first retaining web 158, with which the cell connector 132 is fixed to the holder 148 and which electrically connects the first contact section 154 with an associated conductor track of the circuit board 150, and a second retaining web 160, by means of which the cell connector 132 is also fixed to the holder 148 and which electrically connects the second contact section 156 with an associated conductor track of the circuit board 150. Each cell connector 132 of the electrochemical module 102 is assigned a separate conductor track on the circuit board 150, and these conductor tracks are connected to a (not shown) control unit of the electrochemical device 100, so that the electrical potential of the respective cell connector 132 and the cell terminal 116 assigned to it can be tapped by the control unit via the respective assigned conductor track and the electrically conductive retaining tabs 158 or 160. The first retaining bridge 158 and the second retaining bridge 160 thus also serve as voltage taps 162, via which the electrical potential of the cell connector 132 can be tapped and evaluated by the control unit of the electrochemical device 100. Furthermore, it is possible to carry out charge equalization between different electrochemical cells 104 via the voltage taps 162 using the control unit of the electrochemical device 100. Since the first contact section 154 and the second contact section 156 of the cell connector 132 are at the same electrical potential, it is sufficient if one of the retaining webs 158, 160 is connected to an associated conductor track of the circuit board 150. A particularly simple and time-saving assembly of several cell connectors 132 and, if necessary, also the electrical connections 138 in the form of contact elements 140 on the cell terminals 116 of the electrochemical module 102 is achieved if the base bodies 152 of several cell connectors 132 and preferably also the contact elements of the electrical connections 138 of the module 102 are cut together from a starting material, in particular stamped out, and subsequently form a connector assembly 164 (see Fig. 8), in which the cell connectors 132 are integrally connected to each other by connecting webs 166 and can thus be handled as a unit. In particular, it may be provided that the connector assembly 164, which may be designed as a stamped grid 168, has a frame web 170 surrounding the cell connectors 132 and, if applicable, also the contact elements 140, on which the cell connectors 132 and the contact elements 140 are held by individual connecting web sections 172. This connector assembly 164 is arranged during the assembly of the electrochemical module 102 in the desired arrangement with the electrochemical cells 104 of the module 102, which penetrate the front support frame 124 (see Fig. 7), whereupon the contact sections 154 and 156 of the cell connectors 132 and the contact elements 140 of the electrical connections 138 are connected, preferably by a material bond, to the respective associated cell terminal 116, so that the assembly state shown in Fig. 9 is reached, in which the cell connectors 132 and contact elements 140 of the connector assembly 164 are still integrally connected to each other via the connecting webs 166. Subsequently, the connecting webs 166, i.e. the frame web 170 and the individual connecting web sections 172, are separated from the cell connectors 132 and the contact elements 140, so that the assembly state shown in Fig. 10 is achieved, in which the individual cell connectors 132 and contact elements 140 are no longer electrically connected to each other. To complete the electrochemical module 102, the holder 148 in the form of the circuit board 150 is then arranged on the front of the electrochemical module 102 and connected to the retaining ribs 158, 160 or 146 (preferably by soldering), so that the final assembly state of the electrochemical module 102 shown in Fig. 2 is achieved. In one variant of the above-described method for mounting the cell connectors 132 and the contact elements 140 on the cell terminals 116 of the electrochemical module 102, the connector assembly 164 as a whole is connected to the holder 148 in the form of the circuit board 150 before the cell connectors 132 and the contact elements 140 are arranged in the desired assignment to the electrochemical cells 104 of the module 102 and fixed to them. For this purpose, the retaining webs 158, 160 and 146 of the cell connectors 132 or the contact elements 140 are connected to the conductor tracks of the holder 148, preferably by soldering. Subsequently, the connecting webs 166, i.e. the frame web 170 and the individual connecting web sections 172, are separated from the cell connectors 132 and the contact elements 140, so that the individual cell connectors 132 and contact elements 140 are no longer electrically connected to each other. To complete the electrochemical module 102, the holder 148 in the form of the circuit board 150 with the cell connectors 132 and contact elements 140 held thereon is then arranged on the front of the electrochemical module 102 such that the cell connectors 132 and the contact elements 140 are positioned in the desired arrangement with the electrochemical cells 104 of the module 102, which penetrate the front holder frame 124, whereupon the contact sections 154 and 156 of the cell connectors 132 and the contact elements 140 of the electrical connections 138 are connected, preferably by a material bond, to the respective cell terminal 116, so that finally the final assembly state of the electrochemical module 102 shown in Fig. 2 is also achieved. In another variant of the above-described method for mounting the cell connectors 132 and the electrical connections 138 in the form of the contact elements 140 on the cell terminals 116 of the electrochemical module 102, the connector assembly 164 as a whole is not connected to the holder 148 in the form of the circuit board 150, but to the front holder frame 124 of the electrochemical module 102, as shown in Fig. 51. The cell connectors 132 and the contact elements 140 of the connector assembly 164 are each separately fixed to the front holder frame 124, for example by clamping or locking using suitable clamping elements or locking elements. Subsequently, the connecting webs 166, i.e. the frame web 170 and the individual connecting web sections 172, are separated from the cell connectors 132 and the contact elements 140. In a further step, the front retaining frame 124 with the cell connectors 132 and the contact elements 140 held thereon is placed onto the electrochemical cells 104 of the module 102 in such a way that the front ends of the electrochemical cells 104 penetrate the respective associated through-openings 126 in the front retaining frame 124 and the cell connectors 132 and the contact elements 140 are positioned in the desired arrangement to the electrochemical cells 104 of the module 102. The contact sections 154 and 156 of the cell connectors 132 and the contact elements 140 of the electrical connections 138 are then connected, preferably by material bonding, to the respective associated cell terminal 116. To complete the electrochemical module 102, the holder 148 in the form of the circuit board 150 is then arranged on the front of the electrochemical module 102 and connected to the retaining ribs 158, 160 or 146 (preferably by soldering), so that finally the assembly state of the electrochemical module 102 shown in Fig. 2 is reached. In this variant for mounting the cell connectors 132 and the contact elements 140 on the cell terminals 116, the front retaining frame 124 serves as a holder on which the cell connectors 132 and the contact elements 140 are each separately fixed before the connecting webs 166 of the connector assembly 164 are separated. Various possibilities for the material-bonded connection of a cell connector 132 with the associated first cell terminal 134 and the associated second cell terminal 136 are described below with reference to Figs. 11, 12 to 13: As can be seen, for example, from Fig. 11, the (positive) first cell terminal 134 of an electrochemical cell 104g comprises a base body 174 made of an electrically conductive, preferably metallic, first material, for example aluminum or an aluminum alloy, wherein the first base body 174 has a first contact surface 176 made of the first material associated with the cell connector 132. The second cell terminal 136 of the electrochemical cell 104f, which is to be connected to the first cell terminal 134 by the cell connector 132, comprises a second base body 178 made of an electrically conductive, preferably metallic, corrosion-prone material, for example a low-alloy steel material, wherein the second base body 178 is provided with a corrosion protection layer 180 made of a second material, for example nickel or a nickel alloy, which at the same time forms a first corrosion protection material. The corrosion protection layer 180 has a second contact surface 182 facing the cell connector 132, made of the second material or first corrosion protection material. The base body 152 of the cell connector 132 is preferably formed from the first material, i.e., from the same material as the first base body 174 of the first cell terminal 134. Furthermore, in this embodiment, the cell connector 132 comprises a contact area 184 connected to the base body 152, made of a third material which also forms a second corrosion protection material. The contact area 184 of the cell connector 132 is preferably designed as a contact body 186 manufactured separately from the base body 152 and is fixed in the area of ​​the second contact section 156 of the base body 152, preferably by a material bond, on the side of the base body 152 facing the cell terminals 134, 136. In the embodiment shown in Fig. 11, it is particularly provided that the contact area 184 is fixed to the base body 152 by ultrasonic welding. The third material or the second corrosion protection material from which the contact area 184 is formed can, in particular, be essentially identical to the second material or the first corrosion protection material from which the corrosion protection layer 180 of the second cell terminal 136 is formed. For example, it may be stipulated that the third material or the second corrosion protection material is nickel or a nickel alloy. Alternatively, it can also be provided that the third material or the second corrosion protection material is a chromium alloy. During the assembly of the electrochemical module 102, the base body 152 of the cell connector 132 is connected to the first cell terminal 134 by welding, preferably by laser welding, after the cell connector 132 has been positioned in the desired manner relative to the two cell terminals 134, 136. The contact area 184 of the cell connector 132 is welded to the second cell terminal 136 by a weld seam, which is indicated in Fig. 11 by the broken line 188, wherein the weld seam 188 is preferably produced by laser welding. During this welding process, the corrosion protection layer 180 of the second cell terminal 136 is melted and thereby at least partially penetrated; however, during the welding process, so much of the second corrosion protection material from the contact area 184 containing the second corrosion protection material enters the microstructure and in particular the free surface of the weld seam 188 that, after completion of the welding process, the weld seam 188 is formed of a corrosion-protected material at least on its free surface, but preferably in its entire microstructure. This corrosion-protected material consists predominantly of the corrosion-prone material of the second base body 178 and the second corrosion protection material originating from the contact area 184 of the cell connector 132, by which the corrosion-prone material is alloyed to form a corrosion-protected material. The corrosion protection effect of the first corrosion protection material and / or the second corrosion protection material can be based in particular on the fact that the first corrosion protection material and / or the second corrosion protection material contains at least one corrosion protection metal in a proportion of at least 50 percent by weight. In particular, it may be provided that the first corrosion protection material and / or the second corrosion protection metal contains nickel as a corrosion protection metal. Alternatively or additionally, it may be provided that the first corrosion protection material and / or the second corrosion protection material contains chromium as a corrosion protection metal. The first corrosion protection material and / or the second corrosion protection material may also contain both nickel and chromium as corrosion protection metals, provided that the total proportion of both corrosion protection metals in the first corrosion protection material or in the second corrosion protection material is at least 50 percent by weight. The corrosion resistance of the corrosion-protected material at the free surface of the formed weld 188 is preferably tested by a neutral salt spray test (NSS test) in accordance with DIN EN ISO 9227 (July 2006 edition). Regarding the execution of such a neutral salt spray test, reference is made to the aforementioned standard, and this standard is hereby incorporated into the present description. For the performance of the salt spray test, a specimen 190 of the type shown in Fig. 47, Fig. 48 to Fig. 49 is produced. The specimen 190 comprises a cuboid base 192 with a square end face 194, which has an edge length b of, for example, 12 mm. The base 192 consists of the corrosion-prone material of the second base body 178 of the second cell terminal 136, i.e., for example, the low-alloy steel material which is provided on its surface with the corrosion protection layer made of the first corrosion protection material, for example, nickel or a nickel alloy. A cuboid support 196 is placed on the end face 194, which has a square end face 198 facing the base 192 with an edge length a of, for example, 15 mm and a thickness d of, for example, 0.5 mm, and is connected by welding along an annular closed weld seam 188', in particular by means of a laser weld seam, under the same conditions as when welding the cell connector 132 to the second cell terminal 136. The specimen 190 produced in this way is subjected to the neutral salt spray test (NSS test) in a spray chamber for a test period of 96 hours in accordance with DIN EN ISO 9227 (as of July 2006). After completion of the neutral salt spray test, a visual assessment of the surface of the specimen 190, in particular of the weld 188', and a visual assessment of a section along a section plane 199 running in the axial direction of the specimen 190 through the weld 188' (see Fig. 49) is carried out. During visual inspection, the material of the inspected weld 188' is assigned a rating according to the following rating scheme: - Rating 1: no change, no discoloration, no corrosion; - Rating 2: discoloration or color change, but no corrosion; - Rating 3: traces of corrosion, only a few small, pinpoint areas; - Rating 4: slight corrosion with numerous small, pinpoint areas, but without continuous corroded areas; - Rating 5: moderate corrosion, continuous corroded areas; - Rating 6: severe corrosion, sample completely corroded. In order to be considered corrosion-resistant, the material of the specimen, in particular the weld 188' of the specimen 190, may be rated at most 3 after the neutral salt spray test (NSS test). The rating determined by the neutral salt spray test on the weld 188' of the specimen 190 is assigned to the material of the weld 188 between the second cell terminal 136 and the contact area 184 of the cell connector 132. As an alternative to using a contact body 186 that is manufactured separately from the base body 152 of the cell connector 132 and subsequently joined to the base body 152 by a material bond, a contact area 184 can also be used which comprises a coating produced on the base body 152, in particular an electroplated coating, made of the second corrosion protection material. The base body 152 of the cell connector 132 is preferably made of aluminum or an aluminum alloy. Preferably, the aluminum content of the material of the base body 152 is at least 99.5 percent by weight. In order to minimize mechanical stresses during the operation of the electrochemical device 100, which may arise from different thermal expansions of the cell connectors 132 on the one hand and the receiving device 108 for the electrochemical cells 104 on the other, it is advantageous if the material of the base body 152 of the cell connector 132 has a coefficient of thermal expansion α that differs by less than 10% from the coefficient of thermal expansion α of the material of the receiving device 108. If the coefficients of thermal expansion of these materials vary considerably from the ambient temperature to the operating temperature of the electrochemical device 100, this specification refers to the respective average coefficients of thermal expansion when heated from the ambient temperature (20°C) to the operating temperature of the electrochemical device 100. It is therefore particularly advantageous if the base body 152 and the receiving device 108 are made of essentially the same material, for example both of aluminum or an aluminum alloy. In an alternative possibility for the material-bonded connection of the cell connector 132 with the first cell terminal 134 and the second cell terminal 136, shown schematically in Fig. 12, the contact area 184, which is designed as a contact body 186 produced separately from the base body 152 of the cell connector 132, is not fixed by ultrasonic welding, but by laser welding along a weld seam indicated by line 200 in Fig. 12 on the base body 152. Furthermore, the possibility shown in Fig. 12 for the material-bonded connection of the cell connector 132 with the cell terminals 134 and 136 corresponds with regard to structure, function and method of manufacture to the possibility shown in Fig. 11, to the above description of which reference is made in this respect. An alternative possibility for the material-bonded connection of the cell connector 132 with the cell terminals 134 and 136, shown schematically in Fig. 13, differs from the possibilities shown in Fig. 11 and Fig. 12 in that the cell connector 132 is not welded to the second cell terminal 136, but instead is connected to the second cell terminal 136 by soldering. Furthermore, in this embodiment, the contact area 184 made of the third material or the second corrosion protection material is not formed by a contact body 186 produced separately from the base body 152 and subsequently bonded to the base body 152, but by a coating 202 arranged on the base body 152, for example made of nickel or a nickel alloy. The coating 202 extends at least over the side of the second contact section 156 of the base body 152 that faces the second cell terminal 136 in the assembled state of the electrochemical module 102. As can be seen from Fig. 13, the coating 202 can also extend over the same side of the first contact section 154 and / or over the side of the base body 152 facing away from the cell terminals 134 and 136 in the assembled state. The soldering of the contact area 184 in the form of the coating 202 to the second cell terminal 136 can be carried out, for example, by means of a solder foil 204 made of a soft solder, in particular a lead-free soft solder, for example, the solder with the composition SnAg3.5. Soldering using a soft solder with a low soldering temperature (less than approximately 250°C) offers the advantage that thermally sensitive components of the electrochemical module 102, especially insulating parts made of plastic material, are not damaged during the assembly of the cell connector 132. As an alternative to using a soft solder, a hard solder, for example a silver-based hard solder, can also be used, wherein the hard solder is preferably melted for soldering by means of a short-time laser in order to avoid damage to thermally sensitive components of the electrochemical module 102. The coating 202, which forms the contact area 184 of the cell connector 132, can in particular be an electroplated coating. As an alternative to soldering the contact area 184 of the cell connector 132 to the cell terminal 136, these elements can also be glued together using an electrically conductive adhesive. For bonding, an epoxy resin adhesive with an electrically conductive filler can be used in particular. The electrically conductive filler may include, in particular, silver. The electrically conductive adhesive can be applied to one of the elements to be bonded or to both elements, whereupon both elements are brought into contact with the adhesive layer and the adhesive layer is cured. The curing of the adhesive layer can be achieved in particular by applying heat, at a temperature higher than room temperature. The two elements to be bonded together are preferably pressed against each other under pressure until these elements are bonded together by the adhesive. Suitable electrically conductive adhesives include, in particular, the following: - the silver-containing epoxy resin adhesive marketed under the name LOCTITE® 3880 by Henkel Technologies, Heydastraße 10, 58093 Hagen, Germany. For information regarding the chemical and physical properties and the processing steps for this adhesive, please refer to the technical data sheet for LOCTITE® 3880 dated June 2005, which is hereby incorporated into this description. - the silver-containing hard epoxy adhesive marketed by Master Bond Inc., 154 Hobart Street, Hackensack, NJ 07601-3922, USA, under the name Master Bond Supreme 10HT / S.Regarding the physical and chemical properties and the processing steps for this adhesive, please refer to the technical data sheet for Master Bond Supreme 10HT / S adhesive, and this data sheet is incorporated into this description. This is the silver-containing epoxy resin adhesive distributed by Master Bond Inc., 154 Hobart Street, Hackensack, NJ 07601-3922, USA, under the designation Master Bond FL901S. Regarding the physical and chemical properties and the processing steps for this adhesive, please refer to the technical data sheet for... The adhesive Master Bond FL901S is referenced, and this data sheet is made part of the present description in this respect. During operation of the electrochemical device 100, differences in temperature and / or coefficients of thermal expansion between the cell connectors 132 and the receiving device 108 for the electrochemical cells 104 can lead to a difference in the longitudinal expansion of the cell connectors 132 and a change in the distance between the longitudinal axes 114 of the cell terminals 134 and 136 connected by the cell connectors 132. A temperature change alters the relative positions of the cell terminals 134 and 136 connected by a cell connector 132 in the transverse directions 120 or 122 of the module 102, which are oriented perpendicular to the axial direction 112 of the electrochemical cells 104. Furthermore, due to different longitudinal expansions of the electrochemical cells 104 connected to each other by a cell connector 132, a change in the relative positions between the connected cell terminals 134 and 136 along the axial direction 112 of the connected electrochemical cells 104 may occur. In order to compensate for such differences between a longitudinal elongation of the cell connector 132 on the one hand and a change in the distance between the longitudinal axes 114 of the cell terminals 134 and 136 connected by the cell connector 132 on the other hand and / or such differences between a longitudinal elongation of a first electrochemical cell (for example 104g) and a second electrochemical cell (for example 104f) connected by the cell connector 132, the following is provided in the figures shown in Figs. 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 104f: 30, Fig. 31, Fig. 32, Fig. 33, Fig. 34, Fig. 35, Fig. 36 to Fig.In the alternative embodiments of cell connectors 132 shown in Figure 37, it is provided that the respective cell connector 132 comprises an elastically and / or plastically deformable compensation area 206, which is arranged between the first contact section 154 and the second contact section 156 of the cell connector 132 and connects the two contact sections 154 and 156 together. Preferably, the base body 152 of the cell connector 132 is provided with such a compensation area 206. In the embodiment of a cell connector 132 shown in Figs. 14 and 15, the deformable compensation area 206 has a wave structure, wherein the wave structure comprises several waves with an amplitude directed parallel to the axial direction 112 of the cells 104 to be connected by the cell connector 132 and essentially perpendicular to the contact surfaces 208 and 210, with which the cell connector 132 rests on the first cell terminal 134 and on the second cell terminal 136 respectively in the assembled state.These waves have several, for example four, wave crests extending transversely, preferably substantially perpendicularly, to the axial direction of the electrochemical cells 104 and transversely, preferably substantially perpendicularly, to a longitudinal direction 212 of the cell connector 132 and substantially parallel to a transverse direction 214 of the cell connector 132, which is oriented perpendicularly to the longitudinal direction 212 of the cell connector 132 and perpendicular to the axial direction 112 of the electrochemical cells 104, and wave troughs 218 arranged between the wave crests 216 and extending transversely, preferably substantially perpendicularly, to the axial direction 112 of the electrochemical cells 104, and transversely, preferably substantially perpendicularly, to the longitudinal direction 212 of the cell connector 132 and substantially parallel to the transverse direction 214 of the cell connector 132. The wave crests 216 protrude upwards in a contact direction 217 of the cell connector 132 perpendicular to the contact surfaces 208 and 210 of the cell connector 132, which in the assembled state of the cell connector 132 corresponds to the axial direction 112 of the cells 104, while the wave troughs 218 protrude downwards (towards the cells 104 to be connected) in the contact direction 217. As in the embodiment of a cell connector 132 shown in Figs. 1, 2, 3 to 4, which is essentially planar in the area between the contact sections 154 and 156, the embodiment of a cell connector 132 shown in Figs. 14 and 15, which includes a deformable compensation area 206 between the two contact sections 154 and 156, has two retaining webs 158 and 160 by which the cell connector 132 can be connected to the holder 148 and which can serve for the electrically conductive connection of the cell connector 132 to a conductor leading to the control unit of the electrochemical device 100, so that the retaining webs 158 and 160 can also be used in particular as voltage taps 162. Each of the retaining webs 158 and 160 can be provided with a bend 220 to bridge a height difference between the position of the cell connector 132 and the position of the holder 148 in the axial direction 112 of the electrochemical cells 104. The corrugated structure of the deformable compensation area 206 of the cell connector 132 ensures that the compensation area 206 is easily elastically and / or plastically deformable, allowing the second contact section 156 to be displaced relative to the first contact section 154 both in the axial direction 112 of the electrochemical cells 104 and in the longitudinal direction 212 of the cell connector 132. This compensates for the aforementioned differences in the relative positions of the cell terminals 134 and 136 to be connected by the cell connector 132. This prevents the occurrence of excessive mechanical stresses at the connection points between the cell connector 132 on the one hand and the first cell terminal 134 and the second cell terminal 136 on the other. In particular, by flattening or steepening the wave crests 216 and the wave troughs 218, the extent of the compensation area 206 in the longitudinal direction 212 of the cell connector 132 can be changed, and thus the distance between the first contact section 154 and the second contact section 156 can be increased or decreased. By changing the slopes of the wave crests 216 and the wave troughs 218 asymmetrically, the first contact section 154 and the second contact section 156 can be shifted relative to each other in the axial direction 112 of the electrochemical cells to be connected. The mechanical stresses occurring at these connection points during the operation of the electrochemical device 100 can be further reduced if the deformable compensation area 206 of the cell connector 132 is made of a material with a relatively low yield strength R of at most 60 N / mm2, preferably of at most 40 N / mm2, in particular of at most 20 N / mm2. Furthermore, to reduce the mechanical stresses occurring at the connection points between the cell connector 132 and the cell terminals 134 and 136 to be connected, it can be provided that the cell connector 132 is deformed, preferably plastically, before being connected to the first cell terminal 134 and / or before being connected to the second cell terminal 136, such that the first contact section 154 of the cell connector 132 to be connected to the first cell terminal 134 and the second contact section 156 of the cell connector 132 to be connected to the second cell terminal 136 are displaced relative to each other in such a way that differences in the positions of the first cell terminal 134 and the second cell terminal 136 in the axial direction 112 of the electrochemical cells 104 to be connected, which may be caused, for example, by manufacturing tolerances, are at least partially, preferably substantially completely, compensated. In this case, it is particularly advantageous if the relative positions of the first cell terminal 134 and the second cell terminal 136, which are to be connected by the cell connector 132, are measured before the corresponding deformation of the cell connector 132. Furthermore, the yield strength of the cell connector material 132 in the compensation area 206 and / or in the first contact section 154 and / or in the second contact section 156 can be reduced by heat treatment before and / or during the metallurgical bonding of the cell connector 132 with the first cell terminal 134 and / or with the second cell terminal 136. Such a reduction of the material's yield strength by heat treatment can reduce the mechanical stresses at the connection point during and / or after the metallurgical bonding of the cell connector 132 with the first cell terminal 134 or with the second cell terminal 136. Furthermore, the embodiment of a cell connector 132 shown in Figs. 14, 15 to 16 corresponds in terms of structure, function and manufacturing method to the previously described embodiments of cell connectors 132 without a deformable compensation area 206, to whose preceding description reference is made. An alternative embodiment of a cell connector 132 shown in Figs. 17 and 18 differs from the embodiment shown in Figs. 14, 15 to 16 in that the wave structure of the deformable compensation area 206 has only three wave crests 216 extending in the transverse direction 214 of the cell connector 132 instead of four, and only two wave troughs 218 extending along the transverse direction 214 instead of three. Furthermore, this embodiment of a cell connector 132 does not have retaining webs 158, 160 for connecting the cell connector 132 to the holder 148. Such a cell connector 132 is therefore only held to the electrochemical module 102 by the material-bonded connection with the cell terminals 134 and 136. This embodiment of a cell connector 132 and all embodiments of cell connectors 132 described below, which are shown without retaining webs 158, 160, can in principle also be provided with one or more retaining webs 158 or 160, which can in particular also serve as voltage taps 162. Furthermore, the embodiment of a cell connector 132 shown in Figs. 17 and 18 corresponds in terms of structure, function and method of manufacture to the embodiment shown in Figs. 14, 15 to 16, to whose preceding description reference is made. An alternative embodiment of a cell connector 132 shown in Figs. 19 and 20 differs from the embodiment shown in Figs. 14, 15 to 16 in that the deformable compensation area 206 has a half-ribbed structure instead of a wave structure, which has two rib crests 222 extending in the transverse direction 214 of the cell connector 132 and transitions at a first bend line 224 into the first contact section 154 and at a second bend line 226 into the second contact section 154 of the cell connector 132. Furthermore, the embodiment of a cell connector 132 shown in Figs. 19 and 20 corresponds in terms of structure, function and method of manufacture to the embodiment shown in Figs. 14, 15 to 16, to whose preceding description reference is made. An alternative embodiment of a cell connector 132 shown in Figs. 21 and 22 differs from the embodiment shown in Figs. 14, 15 to 16 in that the deformable compensation area 206 has a wave structure which comprises only a wave crest 216 extending in the transverse direction 214 of the cell connector 132 and only a wave trough 218 extending in the transverse direction 214 of the cell connector 132. Furthermore, the embodiment of a cell connector 132 shown in Figs. 21 and 22 corresponds in terms of structure, function and method of manufacture to the embodiment shown in Figs. 14, 15 to 16, to whose preceding description reference is made in this respect. An alternative embodiment of a cell connector 132 shown in Figs. 23 and 24 differs from the embodiment shown in Figs. 14, 15 to 16 in that the deformable compensation area 206 has a wave structure which comprises two wave crests 216 extending in the transverse direction 214 of the cell connector 132 and a wave trough 218 extending between the wave crests 216 in the transverse direction 214 of the cell connector 132. Moreover, the embodiment of a cell connector 132 shown in Figs. 23 and 24 corresponds in terms of structure, function and method of manufacture to the embodiment shown in Figs. 14, 15 to 16, to whose preceding description reference is made. An alternative embodiment of a cell connector 132 shown in Figs. 25 and 26 differs from the embodiment shown in Figs. 14, 15 to 16 in that the deformable compensation area 206 has a zigzag structure with several, for example five, fold lines 228 extending transversely, preferably substantially perpendicularly, to the axial direction 112 of the electrochemical cells 104 to be connected and substantially along the transverse direction 214 of the cell connector 132. Furthermore, the embodiment of a cell connector 132 shown in Figs. 25 and 26 corresponds in terms of structure, function and method of manufacture to the embodiment shown in Figs. 14, 15 to 16, to whose preceding description reference is made. An alternative embodiment of a cell connector 132 shown in Fig. 27 and Fig. 28 differs from the embodiment shown in Fig. 17 and Fig. 18 in that the cell connector 132 does not have a contact area 184 made of the third material or the second corrosion protection material arranged on the second contact section 156. In principle, however, any embodiment of a cell connector 132 shown in this description and the accompanying drawings without such a contact area 184 can be provided with such a contact area 184. Moreover, the embodiment of a cell connector 132 shown in Figs. 27 and 28 corresponds to the embodiment shown in Figs. 17 and 18, to whose preceding description reference is made. An alternative embodiment of a cell connector 132 shown in Figs. 29 and 30 differs from the embodiment shown in Figs. 14, 15 to 16 in that the cell connector 132 does not have retaining webs 158, 160 for connecting the cell connector 132 to a holder 148. This cell connector 132 is therefore held in the assembled state only by the material-bonded connection with the first cell terminal 134 and the second cell terminal 136 to the electrochemical module 102. Furthermore, the embodiment of a cell connector 132 shown in Figs. 29 and 30 corresponds in terms of structure, function and method of manufacture to the embodiment shown in Figs. 14, 15 to 16, to whose preceding description reference is made. An alternative embodiment of a cell connector 132 shown in Figs. 31, 32 to 33 differs from the embodiment shown in Figs. 27 and 28 in that the base body 152 of the cell connector 132 is not formed in one piece, but is formed as a laminate of several, for example three, layers of material 230 arranged one above the other. The structure enabling elastic and / or plastic deformation of the compensation area 206, in particular its wave structure, remains intact. In all other embodiments of cell connectors 132 disclosed in this description and in the accompanying drawings, the base body 152 can also comprise such a laminate. Furthermore, the embodiment of a cell connector 132 shown in Figs. 31, 32 to 33 corresponds in terms of structure, function and method of manufacture to the embodiment shown in Figs. 27 and 28, to whose preceding description reference is made in this respect. An alternative embodiment of a cell connector 132 shown in Figs. 34 and 35 differs from the embodiment shown in Figs. 27 and 28 in that the deformable compensation area 206 is subdivided by several, for example three, wave-shaped slots 232 into several, for example four, wave-shaped webs 234, which are arranged next to each other in the transverse direction 214 of the cell connector 132. The waveform of the slots 232 and the webs 234 exhibits an amplitude in the transverse direction 214 of the cell connector 132. Furthermore, the cell connector 132 can be provided with several, for example three or four, approximately circular segment-shaped recesses 236 at the lateral edges of the deformable compensation area 206 in order to ensure that the outer webs 234 also have an approximately constant width over their longitudinal extent and also an approximately wave-like shape on their outer side. The slots 232 and the subdivision of the compensation area 206 into several webs 234 increase the deformability of the compensation area 206 and facilitate the creation of an offset between the contact sections 154 and 156 of the cell connector 132. Furthermore, the embodiment of a cell connector 132 shown in Figs. 34 and 35 corresponds in terms of structure, function and method of manufacture to the embodiment shown in Figs. 27 and 28, to whose preceding description reference is made in this respect. An alternative embodiment of a cell connector 132 shown in Figs. 36 and 37 differs from the embodiment shown in Figs. 34 and 35 in that the deformable compensation area 206 is essentially planar and thus does not have a wave structure with an amplitude in the axial direction of the electrochemical cells 104 to be connected. In this embodiment of a cell connector 132, the elastic and / or plastic deformability of the compensation area 206 is caused exclusively by the wave-shaped slots 323, which divide the compensation area 206 into several wave-shaped webs 234, which are arranged next to each other in the transverse direction 214 of the cell connector 132. Furthermore, the embodiment of a cell connector 132 shown in Figs. 36 and 37 corresponds in terms of structure, function and method of manufacture to the embodiment shown in Figs. 34 and 35, to whose preceding description reference is made in this respect. All described embodiments of cell connectors 132 can be provided with at least one through-hole in the first contact section 154 and / or in the second contact section 156 and optionally in the contact area 184 of the cell connector 132 in order to enable electrical contacting of the first cell terminal 134 or the second cell terminal 136, which is materially connected to the cell connector 132, for measurement purposes, which can be used to determine the electrical contact resistance of the connection between the cell connector 132 and the respective cell terminal 134, 136. In the embodiment of an electrochemical device 100 described above, particularly with reference to Fig. 2, the cell connectors 132 and the electrical connections 138 of the electrochemical module 102 are connected to the conductor tracks of a printed circuit board 150 via retaining webs 158, 160 and 146 respectively, wherein the cell connectors 132 and the contact elements 140 of the electrical connections 138 are manufactured separately from the conductor tracks of the printed circuit board 150 and are only electrically connected to the conductor tracks of the printed circuit board 150 during the assembly of the electrochemical module 102. In contrast, in the alternative embodiment of an electrochemical device 100 shown in Fig. 38 and Fig. 39, each cell connector 132 is formed in one piece with an associated conductor track 238. The conductor tracks 238 are not fixed to a circuit board, but are self-supporting. In this embodiment, the contact elements 140 of the electrical connections 138 of the electrochemical module 102 are also preferably formed in one piece with a respective associated conductor track 238. The free ends of the conductor tracks 238 facing away from the cell connectors 132 are electrically connected to a connecting bridge 240, which can be replaced by a plug of a corresponding multi-core cable connection leading to the control unit of the electrochemical device 100, so that the electrical potentials of the cell connectors 132 can be tapped by the control unit. In this embodiment, the cell connectors 132 are held on an auxiliary frame 241, which is made of an electrically insulating material, for example a plastic material, and is shown separately in Fig. 50. The auxiliary frame 241 has an associated recess 243 for each cell connector 132, which allows the passage of the respective cell connector 132 to the cell terminals 134 and 136 to be connected by the cell connector 132 and / or the passage of the cell terminals 134 and 136 to be connected by the cell connector 132 to the respective cell connector 132. Furthermore, the auxiliary frame 241 has a projection 245, on both sides of which the contact elements 140 are arranged (see Fig. 38 ). The conductor tracks 238 can be supported on the auxiliary frame 241. The cell connectors 132 and / or the contact elements 140 can be fixed, for example, by clamping or snapping them onto the auxiliary frame 241, which serves as a holder for the cell connectors 132 and the contact elements 140, using suitable clamping elements or snap-lock elements. The auxiliary frame 241 makes it possible to handle the assembly consisting of the cell connectors 132, the contact elements 140 and the associated conductor tracks 238 of an electrochemical module 102 as a unit during the assembly of the module 102, thus facilitating the assembly of the electrochemical module 102. In the embodiment of the electrochemical device 100 shown in Figs. 38 and 39, the cell connectors 132 and the contact elements 140 initially form a one-piece connector assembly 164 with the conductor tracks 238 and the connecting bridge 240, in which the cell connectors 132 and the contact elements 140 are integrally connected to each other by the conductor tracks 238 and the connecting bridge 240, the connecting bridge 240 being removed when the cell connectors 132 and the contact elements 140 have been metallurgically connected to the respective cell terminals 116 and / or have been connected to the auxiliary frame 241. Furthermore, the embodiment of an electrochemical device 100 shown in Figs. 38 and 39 corresponds in terms of structure, function and method of manufacture to the embodiment shown in Figs. 1, 2, 3 to 4, to whose preceding description reference is made in this respect. Each of the embodiments of an electrochemical device 100 described above can comprise several electrochemical modules 102, which are preferably connected electrically in series. Such a series circuit can be produced in particular by electrically connecting an electrical terminal 138 of a first electrochemical module 102a to an electrical terminal 138 (of opposite polarity) of a second electrochemical module 102b by means of a module connector 242, as shown in Figs. 40, 41 to 42. Details of the module connector 242 can be seen in Figs. 43, 44, 45 to 46, in which the module connector 242 is shown separately. The module connector 242 comprises two plug units 244 for connecting the module connector 242 to the electrical terminals 138 of the electrochemical modules 102a and 102b to be connected to each other, wherein the plug units 244 each comprise a plug housing 246, for example approximately cuboid in shape, which is made, for example, of a metallic material, in particular of a stainless steel material. Each connector housing 246 encloses a receptacle 248, which extends in a connection direction 250 of the module connector 242 and into which a connector section 144 of a contact element 140 of the electrical connection 138 of an electrochemical module 102 can be inserted. As can be seen from Fig. 46, in the inlet 248 two opposing contact tongues 252 are further arranged, between which the respective plug section 144 is clamped under elastic preload when the module connector 242 is arranged on the electrochemical module 102 in question. Furthermore, each connector housing 246 is provided on its outside with locking elements 254 for locking the connector housing 246 to an electrical insulating body (not shown) and with projections 256 which can serve as a guide element and / or as a stop when connecting the respective connector housing 246 to the insulating body in question. The contact tongues 252 of each connector unit 244 are electrically connected to an angled connecting tab 258, which protrudes from the end of the connector housing 246 facing away from the module 102 to be connected and whose free leg 260 extends away from the respective connector housing 246 in a longitudinal direction 262 of the module connector 242, transversely, preferably substantially perpendicularly, to the connection direction 250. The free legs 260 of the connecting lugs 258 of the two plug units 244 are directed in opposite directions along this longitudinal direction 262. The connecting tabs 258 of the two plug units 244 are electrically connected to each other by a flexible conductor 264, which is preferably formed in one piece from a fabric tape 266 woven from electrically conductive wires, in particular from a flat strand and has several, for example four, folds 268. The electrically conductive wires of the fabric tape 266 are preferably made of copper as the electrically conductive component. A first end section 270a of the conductor 264 is fixed to a side of the connecting lug 258 of the first plug unit 244a facing the electrochemical module 102 to be connected in the connected state of the module connector 242, for example by welding, in particular by ultrasonic welding. The first end section 270a extends in the longitudinal direction 262 of the module connector 242 away from the connection tab 258 of the first plug unit 244a, in the direction away from the second plug unit 244b, and can be provided with a bend 271 by which the part of the first end section 270a facing away from the first plug unit 244a is offset along the connection direction 250 towards the module 102 to be connected. The end of the first end section 270a facing away from the connecting flag 258 transitions at a first fold line 272a, which runs obliquely, preferably at an angle of approximately 45°, to the longitudinal direction 262 of the module connector 242 and to the local longitudinal direction of the fabric tape 266 in the first end section 270a, into an approximately trapezoidal first connection section 274a, in which the local longitudinal direction of the conductor 264 runs parallel to a transverse direction 276 of the module connector, which is oriented perpendicular to the longitudinal direction 262 and perpendicular to the connection direction 250 of the module connector 242. The folding 268a at the first fold line 272a is preferably carried out such that the first connecting section 274a is arranged on the side of the first end section 270a facing away from the modules 102 to be connected. The first connecting section 274a transitions through a fold 268b at a second fold line 272b, which runs obliquely, preferably at an angle of approximately 45°, to the transverse direction 276 of the module connector 242 and to the local longitudinal direction 278 of the conductor 264 in the first connecting section 274a, into a compensating section 280, which extends laterally past the plug units 244a and 244b parallel to the longitudinal direction of the module connector 242, wherein the compensating section 280 is offset in the transverse direction 276 of the module connector 242 relative to the plug units 244a, 244b and relative to the first end section 270a of the conductor 264. The compensating section 280 of the conductor 264 can be provided with an electrically insulating covering 282, which may be made, for example, of an elastomeric plastic material, in particular of a PVC material. The broad sides 284, 284' of the ribbon-shaped compensating section 280 of the conductor 264 are oriented essentially perpendicular to the connection direction 250 of the module connector 242. At its end furthest from the first connecting section 274a, the compensating section 280 transitions by means of a fold 268c at a third fold line 272c, which runs obliquely, preferably at an angle of approximately 45°, to the longitudinal direction 262 of the module connector 242 and to the local longitudinal direction 278 of the conductor 264 in the compensating section 280, into a second connecting section 274b, which is essentially trapezoidal and extends from the compensating section 280 in the transverse direction 276 of the module connector 242 to the side of the compensating section 280 on which the plug units 244a and 244b are arranged. The folding takes place at the second fold line 272b and at the third fold line 272c such that the compensating section 280 is arranged on the side of the first connecting section 274a and the second connecting section 274b facing the modules 102a, 102b to be connected. As can be seen in particular from Fig. 45, the compensating section 280 therefore does not extend beyond the connecting lugs 258 of the plug units 244 in the connection direction 250 onto the side of the plug units 244 facing away from the modules 102a, 102b to be connected, so that the module connector 242 has a particularly small extent in the connection direction 250. The second connecting section 274b transitions into a second end section 270b by means of a fold 268d at a fourth fold line 272d running obliquely, preferably at an angle of approximately 45°, to the transverse direction 276 of the module connector 242 and to the local longitudinal direction 278 of the conductor 264 in the second connecting section 274b. This second end section extends from the second connecting section 274a to the terminal tab 258 of the second connector unit 244b and is fixed to the side of this terminal tab 258 facing the modules 102a, 102b to be connected, for example by welding, in particular by ultrasonic welding. The second end section 270b can also be provided with a bend 271, by which the part of the second end section 270b facing away from the second plug unit 244b is offset along the connection direction 250 towards the module 102 to be connected. The folding 268d along the fourth fold line 272d is carried out in such a way that the second end section 270b of the conductor 264 is arranged on the side of the second connecting section 274b facing the modules 102a, 102b to be connected. As can be seen in particular from Fig. 46, the compensating section 280 of the conductor 264 has a length L in the longitudinal direction 262 of the module connector 242, which is greater than the distance D between the opposite ends of the connecting lugs 258 of the plug units 244a, 244b. Due to this large distance available for compensating tolerances and the increased flexibility of the geometric shape of the conductor 264 resulting from the folds 268, the described module connector 242 enables a particularly easy change in the relative positions of the plug units 244a and 244b to each other, so that deviations in the relative position of the plug sections 144 to be inserted into the plug units 244a, 244b of the electrical connections 138 of the electrochemical modules 102a, 102b to be connected, caused by manufacturing tolerances or by changes during the operation of the electrochemical device 100, are compensated particularly easily and effectively.

Claims

Electrochemical device comprising at least a first electrochemical cell (104) with a first cell terminal (134), a second electrochemical cell (104) with a second cell terminal (136), and a cell connector (132) electrically connecting the first cell terminal (134) and the second cell terminal (136), wherein the cell connector (132) comprises a first contact section (154) for connecting to the first cell terminal (134), a second contact section (156) for connecting to the second cell terminal (136), and an elastically and / or plastically deformable compensation area (206) that connects the first contact section (154) and the second contact section (156) and allows movement of these contact sections (154, 156) relative to each other.wherein the electrochemical device (100) comprises a receiving device (108) with at least a first receiving for the first electrochemical cell (104) and a second receiving for the second electrochemical cell (104), wherein the cell connector (132) comprises a base body (152) formed from a material having a coefficient of thermal expansion α that differs by less than 10% from the coefficient of thermal expansion α of the material of the receiving device (108), and wherein the receiving device (108) is configured as a heat sink (110) which is in thermally conductive contact with the electrochemical cells (104) received therein. Electrochemical device according to claim 1, characterized in that the compensation area (206) of the cell connector (132) has at least one wave (216, 218) or bead (222) or kink line (228) extending transversely to the longitudinal direction (212) of the cell connector (132). Electrochemical device according to one of claims 1 or 2, characterized in that the compensation area (206) of the cell connector (132) comprises at least one web (234). Electrochemical device according to claim 3, characterized in that the bridge (234) connects the first contact section (154) of the cell connector (132) and the second contact section (156) of the cell connector (132) together. Electrochemical device according to one of claims 1 to 4, characterized in that the cell connector (132) comprises two or more layers of material (230) laminated together. Electrochemical device according to one of claims 1 to 5, characterized in that the cell connector (132) has at least one voltage tap (151). Electrochemical device according to one of claims 1 to 6, characterized in that the compensation area (206) of the cell connector (132) is formed from a material with a yield strength R of at most 60 N / mm2. Electrochemical device according to one of claims 1 to 7, characterized in that the electrochemical device (100) is designed as an accumulator. Method for electrically connecting a first cell terminal (134) of a first electrochemical cell (104) to a second cell terminal (136) of a second electrochemical cell (104) of an electrochemical device (100), comprising the following process steps: - providing a cell connector (132) comprising a first contact section (154) for connecting to the first cell terminal (134), a second contact section (158) for connecting to the second cell terminal (136), and an elastically and / or plastically deformable compensation area (206) that connects the first contact section (154) and the second contact section (156) and allows movement of these contact sections (154, 156) relative to each other; - connecting the cell connector (132) to the first cell terminal (134) and to the second cell terminal (136);wherein the electrochemical device (100) comprises a receiving device (108) with at least a first receiving (106) for the first electrochemical cell (104) and a second receiving (106) for the second electrochemical cell (104), wherein the cell connector (132) comprises a base body (152) formed from a material having a coefficient of thermal expansion α that differs by less than 10% from the coefficient of thermal expansion α of the material of the receiving device (108), and wherein the receiving device (108) is configured as a heat sink (110) which is in thermally conductive contact with the electrochemical cells (104) received therein. The method according to claim 9, characterized in that the cell connector (132) is deformed before being connected to the first cell terminal (134) and / or before being connected to the second cell terminal (136) such that the first contact section (154) of the cell connector (132) to be connected to the first cell terminal (134) and the second contact section (156) of the cell connector (132) to be connected to the second cell terminal (136) are displaced relative to each other in such a way that differences in the positions of the first cell terminal (134) and the second cell terminal (136) in the axial direction (112) of the first electrochemical cell (104) and the second electrochemical cell (104) are at least partially compensated. Method according to claim 10, characterized in that the relative positions of the first cell terminal (134) and the second cell terminal (136) in the axial direction (112) of the first electrochemical cell (104) and the second electrochemical cell (104) are measured before the deformation of the cell connector (132). Method according to one of claims 9 to 11, characterized in that the yield strength of at least a part of the material of the cell connector (132) is reduced by heat treatment before and / or during the connection of the cell connector (132) with the first cell terminal (134) or with the second cell terminal (136).

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