WO2025087867A1 - Cell contacting system for an electrochemical module and electrochemical module of an electrochemical device - Google Patents

Abstract

The invention relates to a cell contacting system for an electrochemical module which comprises a plurality of cell groups, each of which comprises a plurality of electrochemical cells, each electrochemical cell having a first cell terminal and a second cell terminal, the cell terminals being contacted by means of electrically conductive contact regions which follow the associated cell terminal along a contacting direction, the first cell terminals of a first cell group having the highest electric potential and the second cell terminals of a second cell group having the lowest electric potential and the first cell terminals of the first cell group being electrically connected to a first busbar and the second cell terminals of the second cell group being electrically connected to a second busbar, the electrochemical cells of the first cell group following one another along the longitudinal direction and the electrochemical cells of the second cell group following one another along the longitudinal direction and at least one of the busbars having a main surface which extends parallel to the longitudinal direction. In order to provide a cell contacting system of this type which at least partially overcomes the problems of known cell contacting systems, according to the invention the main surface of the at least one busbar extends substantially parallel to the contacting direction of the electrochemical module.

Description

Cell contact system for an electrochemical module and electrochemical module of an electrochemical device

The present invention relates to a cell contacting system for an electrochemical module of an electrochemical device, wherein the electrochemical module comprises a plurality of cell groups, each of which comprises a plurality of electrochemical cells, wherein each electrochemical cell has a first cell terminal and a second cell terminal, wherein the cell terminals are contacted by means of electrically conductive contact regions which follow the respective cell terminal along a contacting direction, wherein the first cell terminals of the electrochemical cells of a first cell group have the highest electrical potential during operation of the electrochemical module and the second cell terminals of the electrochemical cells of a second cell group have the lowest electrical potential during operation of the electrochemical module, and wherein the first cell terminals of the electrochemical cells of the first cell group are electrically conductively connected to a first current collecting bar and the second cell terminals of the electrochemical cells of the second cell group are electrically conductively connected to a second current collecting bar, wherein the electrochemical cells of the first cell group follow one another along a longitudinal direction of the electrochemical module and the electrochemical cells of the second cell group follow one another along the longitudinal direction of the electrochemical module and at least one of the current collecting bars has a main surface which extends parallel to the longitudinal direction of the electrochemical module.

A known cell contacting system for an electrochemical module of an electrochemical device of the above-mentioned type comprises two current collecting bars whose main surfaces extend parallel to the longitudinal direction or X-direction of the electrochemical module and perpendicular to the contacting direction or Z-direction of the electrochemical module. These two busbars are located in an additional layer above the cell terminals of the electrochemical cells and above cell connectors, through which the first cell terminals and second cell terminals of the electrochemical cells of the electrochemical module are electrically connected to one another. The arrangement of these two busbars in this additional layer above the cell terminals and the cell connectors for the series and parallel connection of the electrochemical cells of the electrochemical module requires additional installation space along the contact direction or Z-direction of the electrochemical module.

Furthermore, it is necessary to insert an electrically insulating layer between each of the busbars and the cell connectors arranged underneath to prevent short circuits.

Since the busbars each cover some of the electrochemical cells and at least sections of the cell connectors, several consecutive steps are necessary to manufacture the cell contact system comprising these busbars. First, the cell connectors must be contacted with the cell terminals of the electrochemical cells. Then, the electrical insulation layer must be arranged on at least some of the cell connectors and the electrochemical cells. Only then can the busbars be positioned over the cell connectors and the electrochemical cells and contacted with the first cell terminals of the electrochemical cells of the first cell group or with the second cell terminals of the electrochemical cells of the second cell group.

The fact that the busbars at least partially cover the cell connectors and the electrochemical cells of the electrochemical module also brings disadvantages with regard to the dissipation of heat from the electrochemical cells in the event of a so-called "thermal runaway". escaping hot gases. These hot gases remain in the space between the electrochemical cells and the busbars above them, which can cause other electrochemical cells located beneath the same busbar to heat up and then also enter a "thermal runaway" state, causing these other electrochemical cells to also release hot gas.

Furthermore, the electrochemical cells and cell connectors, each concealed by a busbar, cannot be directly exposed to or surrounded by a cooling medium from an immersion cooling system. This reduces the cooling performance of any immersion cooling system that may be present.

The present invention is based on the object of creating a cell contacting system of the type mentioned at the outset which at least partially overcomes the problems of the known cell contacting system explained above.

This object is achieved according to the invention in a cell contacting system having the features of the preamble of claim 1 in that the main surface of the at least one current collecting bar extends substantially parallel to the contacting direction of the electrochemical cells of the electrochemical module.

The fact that the at least one current busbar extends with its main surface not perpendicular to the contact direction or Z-direction of the electrochemical module, but essentially parallel to the contact direction or Z-direction, prevents cell terminals and cell connectors of the electrochemical module from being covered by this current busbar - seen along the contact direction or Z-direction of the electrochemical module. Because the at least one current busbar is not arranged in an additional level above the cell terminals and the cell connectors of the electrochemical module, the electrochemical module has a lower overall height in the contacting direction or Z-direction, at least in the region of this current busbar, when using the cell contacting system according to the invention.

Because the at least one current busbar does not cover any cell terminals of electrochemical cells or any cell connectors of the electrochemical module, the electrically conductive connection of the electrochemical cells to the cell connectors on the one hand and the electrically conductive connection of the cell terminals of the first cell group and the second cell group to the respectively assigned current busbar can be made simultaneously, in a single work step.

Furthermore, in the event of a thermal runaway of one of the electrochemical cells in the electrochemical module, the escaping hot gas can freely vent through the cell contact system and be removed from the electrochemical module. This prevents the hot gas from accumulating in a plane above the cell connectors and causing further thermal runaways of electrochemical cells.

Furthermore, the cell terminals of the electrochemical cells of the electrochemical module and the cell connectors can be directly surrounded by the cooling medium of an immersion cooling system.

The busbar, which is aligned with its main surface parallel to the contact direction or Z-direction and parallel to the longitudinal direction or X-direction of the electrochemical module, can also be surrounded by a cooling medium. This increases the achievable cooling capacity and thus the performance of the electrochemical module. In a preferred embodiment of the cell contacting system according to the invention, it is provided that both current collecting rails of the module each have a main surface which extends parallel to the longitudinal direction or X-direction of the electrochemical module and parallel to the contacting direction of the electrochemical cells of the electrochemical module (Z-direction of the electrochemical module).

In this way, it is ensured that the cell contacting system does not include a current collecting bar that covers a cell terminal or a cell connector of the electrochemical module - seen in the contacting direction - so that the entire cell contacting system can be contacted with the electrochemical cells of the electrochemical module in a single operation.

Furthermore, it is impossible for hot gas escaping from an electrochemical cell in the event of a thermal runaway to be trapped between the cell terminals and cell connectors of the electrochemical module on the one hand and a current busbar of the cell contact system on the other hand, thus causing further thermal runaways of electrochemical cells.

In addition, in this case, the cell terminals of all electrochemical cells of the electrochemical module and all cell connectors can be directly surrounded by the cooling medium of an immersion cooling system.

Furthermore, all current busbars of the cell contact system can be surrounded by a cooling medium, which increases the achievable cooling capacity and thus the performance of the electrochemical module.

In order to save material and weight in the busbars, it is advantageous if an electrically conductive cross-section taken perpendicular to the longitudinal direction or X-direction of the electrochemical module at least one of the busbars increases at least in sections from one end region to the other end region of the relevant busbar.

In this way, the local current carrying capacity of the current busbar is adapted to the respective requirements at different locations along the longitudinal direction of the electrochemical module, because the sum of the currents to be discharged by the current busbar from the cell terminals of the respectively assigned cell group or the sum of the currents to be supplied to the cell terminals of the respectively assigned cell group decreases with increasing distance from the end region of the current busbar, which is closer to the external power connection of the electrochemical module.

It is preferably provided that the electrically conductive cross section of at least one of the busbars taken perpendicular to the longitudinal direction of the electrochemical module increases monotonically, particularly preferably continuously, from one end region to the other end region of the relevant busbar.

This increase in the electrically conductive cross section can be achieved in particular by a transverse extension of the at least one current busbar along the contacting direction of the electrochemical cells of the electrochemical module from one end region to the other end region of the relevant current busbar along the longitudinal direction of the electrochemical module increasing at least in sections, in particular monotonously, particularly preferably continuously.

Alternatively or in addition to this variation of the transverse extent of the at least one busbar, it can be provided that a material thickness of the at least one busbar increases from one end region to the other end region of the relevant busbar along the longitudinal direction of the electrochemical module, at least in sections, in particular monotonously, preferably continuously. The material thickness of the at least one busbar is its extension perpendicular to the longitudinal direction of the electrochemical module and perpendicular to the contact direction of the electrochemical cells of the electrochemical module.

In a preferred embodiment of the invention, it is provided that at least one of the busbars comprises at least one contact element for electrically conductive connection to a cell terminal of an electrochemical cell of a cell group adjacent to the busbar.

The at least one contact element preferably has a contact surface at which the contact element can be connected to the cell terminal of an electrochemical cell, preferably in a materially bonded manner, in particular by welding, particularly preferably by laser welding, wherein the contact surface is aligned substantially perpendicular to a main surface of the base body of the busbar.

Furthermore, it is advantageous if the at least one contact element comprises a contact region at which the contact element can be connected to a cell terminal of an electrochemical cell, preferably in a materially bonded manner, in particular by welding, particularly preferably by laser welding, and an elastically and/or plastically deformable compensation region via which the contact region is connected to the base body of the busbar.

Such a compensation area can compensate for manufacturing tolerances during assembly of the cell contact system to the electrochemical cells of the electrochemical module as well as at least partially compensate for changes in the relative positions between the various cell terminals of the same cell group during operation of the electrochemical device, which are caused, for example, by shock, vibrations or age-related dimensional changes of the electrochemical cells and the reduce the mechanical stresses acting on the connection point between a contact area of a current busbar and a cell terminal of an electrochemical cell.

In a preferred embodiment of the invention, it is provided that the at least one contact region, the at least one compensation region and the at least one base body of the respective busbar are formed integrally with one another.

Preferably, the busbar is designed as a stamped and bent body.

At least one of the busbars may be formed by cutting out of a flat starting material and at least partially reshaping the cut-out starting material.

In a preferred embodiment of the invention, it is provided that at least one of the busbars is formed from an aluminum material.

The cell contacting system according to the invention is particularly suitable for use as a component of an electrochemical module of an electrochemical device, wherein the electrochemical module comprises a plurality of cell groups, each of which comprises a plurality of electrochemical cells, and wherein the electrochemical module comprises a cell contacting system according to the invention.

It is preferably provided that several electrochemical cells of the electrochemical module are arranged at least partially between the two current busbars. Preferably, all electrochemical cells of the electrochemical module are arranged at least partially between the two current collecting bars of the cell contacting system.

In order to overcome the above-mentioned disadvantages of the known cell contacting system, it is advantageous if no component of one of the current busbars completely covers one of the electrochemical cells of the electrochemical module - seen in the contacting direction of the electrochemical cells of the electrochemical module.

The electrochemical module can in particular be designed as a battery module of an electrochemical device which is designed as a battery storage device.

The electrochemical cells of the electrochemical module can, for example, be lithium-ion batteries.

An electrochemical device comprising at least one such battery module is suitable, for example, as an energy storage device for an electric vehicle or for stationary storage purposes, for example as an energy buffer for a photovoltaic system or a wind turbine.

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

The drawings show:

Fig. 1 is a top plan view of an electrochemical module of an electrochemical device according to the prior art, the electrochemical module comprising several cell groups, which each comprise a plurality of electrochemical cells, wherein each electrochemical cell has a first cell terminal and a second cell terminal, wherein the cell terminals are contacted by means of electrically conductive contact areas which follow the respective cell terminal along a contacting direction, wherein the first cell terminals of the electrochemical cells of a first cell group have the highest electrochemical potential during operation of the electrochemical module and the second cell terminals of the electrochemical cells of a second cell group have the lowest electrochemical potential during operation of the electrochemical module, and wherein the first cell terminals of the electrochemical cells of the first cell group are electrically conductively connected to a first current collecting bar and the second cell terminals of the electrochemical cells of the second cell group are electrically conductively connected to a second current collecting bar, wherein the electrochemical cells of the first cell group follow one another along a longitudinal direction of the electrochemical module and the electrochemical cells of the second cell group follow one another along the longitudinal direction of the electrochemical module, and wherein the two current collecting bars each have a main surface which extends parallel to the longitudinal direction of the electrochemical module and perpendicular to the contact directions of the electrochemical cells;

Fig. 2 is a perspective view of an embodiment of an electrochemical module of an electrochemical device according to the invention, which differs from the embodiment shown in Fig. 1 in particular in that the two current collecting rails of the cell contacting system each have a main surface which extends parallel to the longitudinal direction of the electrochemical module and parallel to the contact directions of the electrochemical cells of the electrochemical module, wherein the electrochemical cells of the electrochemical module are arranged at least partially between the two current collecting bars, so that the two current collecting bars are arranged parallel to one another on opposite sides of the electrochemical module and are spaced apart from one another in a transverse direction of the electrochemical module oriented perpendicular to the longitudinal direction of the module and perpendicular to the contact directions of the electrochemical cells, with the viewing direction towards an upper side of the cell contacting system of the electrochemical module facing away from the electrochemical cells;

Fig. 3 is a perspective view of the cell contacting system of the electrochemical module from Fig. 2, viewed from below onto a side of the cell contacting system facing the electrochemical cells of the electrochemical module during operation of the electrochemical module;

Fig. 4 is a plan view of the side of the cell contacting system of Fig. 3 facing the electrochemical cells during operation of the electrochemical module, seen along the contacting direction;

Fig. 5 is a view of the cell contacting system of Figs. 3 and 4 along the longitudinal direction of the cell contacting system, looking in the direction of arrow 5 in Fig. 4; Fig. 6 is a perspective view of a cell connector of the cell contacting system of Figs. 3 to 5, by means of which the first cell terminals of a first cell group and the second cell terminals of a second cell group of the electrical module are connected in parallel to one another and the first cell group and the second cell group are connected in series with one another;

Fig. 7 is a partial plan view of the cell connector from Fig. 6;

Fig. 8 is a perspective view of a first current collecting bar of the cell contacting system;

Fig. 9 is a top plan view of the first busbar of Fig. 8;

Fig. 10 is a side view of the first current collecting bar, seen parallel to the transverse direction of the cell contacting system, looking in the direction of arrow 10 in Fig. 9;

Fig. 11 is a view of the first current collecting bar parallel to the longitudinal direction of the cell contacting system, looking in the direction of arrow 11 in Fig. 10;

Fig. 12 is a perspective view of a second current busbar of the cell contacting system;

Fig. 13 is a top plan view of the second busbar of Fig. 12;

Fig. 14 is a side view of the second current collecting bar, parallel to the transverse direction of the cell contacting system, looking in the direction of arrow 14 in Fig. 13; Fig. 15 is a view of the second current collecting bar parallel to the longitudinal direction of the cell contacting system, looking in the direction of arrow 15 in Fig. 14;

Fig. 16 is a perspective view of a plate-shaped support element of the cell contacting system; and

Fig. 17 is a top view of the plate-shaped support element of the cell contacting system from Fig. 16.

Identical or functionally equivalent elements are designated by the same reference numerals in all figures.

An embodiment of an electrochemical module of an electrochemical device 102, designated as a whole by 100, shown in Fig. 1, which is not according to the invention, comprises a plurality of electrochemical cells 104, which in the illustrated embodiment are designed as substantially cylindrical round cells 106.

The electrochemical cells 104 are preferably arranged at the positions of a hexagonal grid, so that (except for the edge electrochemical cells 104) each electrochemical cell 104 is surrounded by six neighboring electrochemical cells 104.

Each of the electrochemical cells 104 comprises a first cell terminal which is arranged centrally on the electrochemical cell 104 and extends along a contact direction 108 which is aligned parallel to the longitudinal central axis of the electrochemical cell 104.

Each of the electrochemical cells 104 further has a second cell terminal whose polarity is opposite to the polarity of the first cell terminal. In the present embodiment, the first cell terminals have a positive polarity and the second cell terminals have a negative polarity.

In principle, however, it can also be provided that the first cell terminals have a negative polarity and the second cell terminals have a positive polarity.

In the embodiment shown in the drawing, it is provided that the second cell terminal of each electrochemical cell 104 is arranged on the same end face of the electrochemical cell 104 as the first cell terminal.

It is preferably provided that the second cell terminal surrounds the first cell terminal in a ring shape.

In particular, it can be provided that the second cell terminal is arranged on the outer circumference of the front side of the electrochemical cell 104.

Of course, the first cell terminal and the second cell terminal of the same electrochemical cell 104 are electrically isolated from each other.

The electrochemical cells 104 are arranged in a housing 110 of the electrochemical module 100.

The housing 110 comprises first boundary walls 112 which extend in a longitudinal direction 114 of the electrochemical module 100, which is also referred to below as the X-direction of the electrochemical module 100.

Furthermore, the housing 110 comprises second boundary walls 116 which extend in a transverse direction 118 of the electrochemical module 100, which is also referred to below as the Y-direction of the electrochemical module 100. Furthermore, the housing 110 comprises a housing base (not shown) on which the electrochemical cells 104 are arranged and which can preferably be cooled by means of a cooling device (not shown) of the electrochemical module 100 or itself forms a component of such a cooling device.

The housing base is preferably oriented perpendicular to the contact direction 108 of the electrochemical module 100, which is also referred to below as the Z-direction of the electrochemical module 100.

The longitudinal direction 114 or X-direction of the electrochemical module 100 and the transverse direction 118 or Y-direction of the electrochemical module 100 are preferably aligned perpendicular to the contacting direction 108 or Z-direction of the electrochemical module 100.

Furthermore, the longitudinal direction 114 or X-direction of the electrochemical module 100 and the transverse direction 118 or Y-direction of the electrochemical module 100 are preferably aligned perpendicular to each other.

The electrochemical module 100 further comprises a cell contacting system 120, which preferably closes an opening of the housing 110 of the electrochemical module 100.

The cell contacting system 120 preferably comprises a carrier element 122 and cell connectors 124 arranged on the carrier element 122.

The electrochemical cells 104 form cell groups 126, the first cell terminals and/or the second cell terminals of which are each at the same electrical potential. In the embodiment shown in Fig. 1, 27 electrochemical cells 104a, whose first cell terminals have the highest electrochemical potential during operation of the electrochemical module 100 and which follow one another along the longitudinal direction 114 of the electrochemical module 100 adjacent to the first boundary wall 112a shown at the bottom in Fig. 1, form a first cell group 126a of the electrochemical module 100.

Correspondingly, in the embodiment shown in Fig. 1, 27 electrochemical cells 104, whose second cell terminals have the lowest electrochemical potential during operation of the electrochemical module 100 and follow one another along the longitudinal direction 114 of the electrochemical module 100 adjacent to the first boundary wall 112b shown at the top in Fig. 1, form a second cell group 126b of the electrochemical module 100.

The cell contacting system 120 of the electrochemical module 100 further comprises a first current collecting bar 128a having a main surface 130a having an approximately trapezoidal shape and extending parallel to the longitudinal direction 114 and parallel to the transverse direction 118 of the electrochemical module 100 and perpendicular to the contacting direction 108 across numerous electrochemical cells 104 of the electrochemical module 100.

The width of the first busbar 128a, i.e. its extension along the transverse direction 118 of the electrochemical module 100, initially increases from right to left in Fig. 1 and then remains constant.

At its left end, the first bus bar 128a is connected to a power terminal (not shown) of the electrochemical module 100, to which a module connector (also not shown) for connecting the electrochemical module 100 to another electrochemical module 100 or to another component of an electrical charge/discharge circuit can be connected. Thus, the electrically conductive cross section of the first current busbar 128a also increases with decreasing distance from the power connection of the electrochemical module 100, which is sensible because the first current busbar 128a has to carry the current from more and more electrochemical cells 104 of the first cell group 126a with decreasing distance from the power connection of the electrochemical module 100.

The first current collecting bar 128a is electrically conductively connected to the central first cell terminals of the electrochemical cells 104 of the first cell group 126a via a respective connection region 132 and a respective first contact region 134.

The first contact regions 134 are preferably connected to the central first cell terminal of the electrochemical cells 104 of the first cell group 126a in a materially bonded manner, in particular by welding, preferably by laser welding.

The connecting region 132 located between the base body 136 and a respective first contact region 134 is elastically and/or plastically deformable in order to be able to compensate for manufacturing tolerances and/or positional tolerances occurring during operation of the electrochemical module 100 between the first cell terminals of the electrochemical cells 104 of the first cell group 126a.

The cell contacting system 120 further comprises a second bus bar 128b, which is electrically conductively connected to the second cell terminals of the electrochemical cells 104 of the second cell group 126b of the electrochemical module 100. As can be seen from Fig. 1, the second busbar 128b is designed and arranged substantially mirror-symmetrically with respect to a longitudinal center plane 138 of the electrochemical module 100, which extends parallel to the contacting direction 108 and parallel to the longitudinal direction 114 of the electrochemical module 100.

The second busbar 128b is also connected at its left end (in Fig. 1) to a power connection (not shown) of the electrochemical module 100, wherein this power connection can also be connected via a module connector (not shown) to another electrochemical module 100 or to another component of the charge/discharge circuit.

The electrically conductive cross section of the second busbar 128b also increases, at least in sections, from right to left due to an increase in the width of the second busbar 128b, i.e., its extension along the transverse direction 118 of the electrochemical module 100.

The second busbar 128b is electrically conductively connected to a second cell terminal of an electrochemical cell 104 of the second cell group 126b via a connection region 132 and a second contact region 140.

The second contact region 140 is preferably connected in a materially bonded manner, in particular by welding, preferably by laser welding, to the respective second cell terminal of an electrochemical cell 104 of the second cell group 126b.

The second cell terminals of the electrochemical cells 104 of the second cell group 126b are connected in parallel to one another by the second current busbar 128b. The first cell terminals of the electrochemical cells 104 of the first cell group 126a are connected in parallel to one another by the first current busbar 128a.

Since the two current busbars 128a and 128b are located in an additional layer above the cell connectors 124 for the series and parallel connection of the remaining electrochemical cells 104 of the electrochemical module 100, additional installation space is required along the contact direction 108 or Z-direction.

Furthermore, it is necessary to insert an electrically insulating layer between each of the busbars 128a, 128b and the cell connectors 124 arranged underneath them in order to avoid short circuits.

Since the bus bars 128a and 128b each cover some of the electrochemical cells 104 and at least portions of the cell connectors 124, several sequential steps are necessary to manufacture the cell contacting system 120.

First, the cell connectors 124 must be contacted with the cell terminals of the electrochemical cells 104. Then, the electrical insulation layer must be arranged on at least a portion of the cell connectors 124 and the electrochemical cells 104. Only then can the current collecting bars 128a and 128b be positioned over the cell connectors 124 and over the electrochemical cells 104 and contacted with the first cell terminals of the electrochemical cells 104 of the first cell group 126a and with the second cell terminals of the electrochemical cells 104 of the second cell group 126b, respectively. The fact that the busbars 128a and 128b at least partially cover the cell connectors 124 and the electrochemical cells 104 of the electrochemical module 100 also entails disadvantages with regard to the removal of gases escaping from the electrochemical cells 104.

A hot gas escaping from an electrochemical cell 104 spreads beneath one of the current busbars 128a, 128b without being able to be dissipated by the electrochemical cells 104. This causes other electrochemical cells 104 located beneath the same current busbar 128a or 128b to heat up and then also enter a so-called "thermal runaway" state, causing these other electrochemical cells to also release hot gas.

In order to provide a means of discharging such hot gases away from the electrochemical cells 104, through-openings would have to be provided in the current collecting bars 128a and 128b; however, such through-openings would lead to a reduction in the current-carrying capacity of the current collecting bars 128a, 128b.

If the electrochemical module 100 is to be cooled by immersion cooling, the electrochemical cells 104 and cell connectors 124, each concealed by a busbar 128a or 128b, cannot be directly exposed to the respective cooling medium or be surrounded by the cooling medium. This reduces the cooling capacity of the immersion cooling system and thus the performance of the electrochemical module 100.

A second embodiment of an electrochemical module 100 according to the invention shown in Figs. 2 to 17 differs from that shown in Fig. 1 illustrated first embodiment in that the first current collecting bar 128a and the second current collecting bar 128b of the cell contacting system 120 are designed and arranged such that their main surfaces 130a and 130b respectively extend substantially parallel to the contact direction 108 or Z-direction of the electrochemical module 100 and parallel to the longitudinal direction 114 or X-direction of the electrochemical module 100.

As can be seen from Fig. 8, which shows the first power connection rail 128a as a whole, and from Fig. 10, which shows the rear region of the first power connection rail 128a facing away from the power connection of the electrochemical module 100, the electrically conductive cross section of the first power collection rail 128a, taken perpendicular to the longitudinal direction 114 or X-direction of the electrochemical module 100, increases at least in sections from one end region 142 to the other end region 144, which is closer to the power connection of the electrochemical module 100, and in particular preferably monotonically, particularly preferably continuously.

In the rear region of the first busbar 128a facing away from the power connection of the electrochemical module 100, its lower edge 146 facing away from the first contact regions 134 runs obliquely to the longitudinal direction 114 or X-direction of the electrochemical module 100 and obliquely to the contacting direction 108 or Z-direction of the electrochemical module 100.

In a front region facing the power connection of the electrochemical module 100, the lower edge 146 of the first busbar 128a preferably runs substantially parallel to the longitudinal direction 114 or X-direction of the electrochemical module 100 and preferably substantially perpendicular to the contacting direction 108 or Z-direction of the electrochemical module 100. The transverse extent of the first busbar 128a along the contacting direction 108 or Z-direction of the electrochemical module 100 therefore increases from the one end region 142, which faces away from the power connection of the electrochemical module 100, to a transition point 148 and is then preferably substantially constant from the transition point 148 to the other end region 144 of the first busbar 128a, which is closer to the power connection of the electrochemical module 100.

In the embodiment of the cell contacting system 120 shown in the drawing, it is provided that the material thickness of the base body 136 of the first busbar 128a is substantially constant along the longitudinal direction 114 or X-direction of the electrochemical module 100.

In a variant of this embodiment, however, it could be provided that the material thickness of the base body 136, that is to say its extent along the transverse direction 118 or Y-direction of the electrochemical module 100, increases at least in sections from one end region 142 to the other end region 144 of the first busbar 128a along the longitudinal direction 114 or X-direction of the electrochemical module 100, preferably monotonically, particularly preferably continuously.

As can be seen from Figs. 8 to 11, the first current collecting bar 128a comprises for each electrochemical cell 104 of the first cell group 126a a contact element 152 for electrically conductive connection to the first cell terminal of each electrochemical cell 104 of the first cell group 126a.

Each of these contact elements 152 has a - preferably substantially flat - contact surface 150, at which the respective contact element 152 is connected to the first cell terminal of an electrochemical cell 104 the first cell group 126a, wherein this contact surface 150 is preferably oriented substantially perpendicular to the main surface 130a of the base body 136 of the first busbar 128a and preferably perpendicular to the contacting direction 108 or Z-direction of the electrochemical module 100.

Each of the contact elements 152 of the first busbar 128a has a first contact region 134, on which the contact surface 150 is arranged and on which the contact element 152 can be connected, preferably in a materially bonded manner, in particular by welding, particularly preferably by laser welding, to the central first cell terminal of an electrochemical cell 104 of the first cell group 126a.

Furthermore, each contact element 152 of the first busbar 128a has an elastically and/or plastically deformable compensation region 154, via which the respective first contact region 134 is connected to the base body 136 of the first busbar 128a.

In the embodiment of an electrochemical module 100 shown in the drawing, it is provided that all first contact regions 134 of the first current busbar 128a, all compensation regions 154 of the first current busbar 128a and the base body 136 of the first current busbar 128a are formed integrally with one another.

The second busbar 128b, which is shown in Fig. 12 as a whole and in Figs. 13 to 15 in detail, in its rear region facing away from the second power connection of the electrochemical module 100 assigned to the second busbar 128b, is designed and arranged mirror-symmetrically with respect to the longitudinal central axis 138 of the electrochemical module 100, except for the design of the contact elements 152. The second busbar 128b also has a main surface 130b which extends parallel to the contacting direction 108 or Z-direction of the electrochemical module 100 and parallel to the longitudinal direction 114 or X-direction of the electrochemical module 100.

An electrically conductive cross section of the second current busbar 128b taken perpendicular to the longitudinal direction 114 or X-direction of the electrochemical module 100 increases at least in sections, preferably monotonically, particularly preferably continuously, from one end region 142 of the second current busbar 128b, which faces away from the second current connection of the electrochemical module 100, to the other end region 144 of the second current busbar 128b, which faces the second current connection of the electrochemical module 100.

The transverse extent of the second busbar 128b along the contacting direction 108 or Z-direction of the electrochemical module 100 also increases at least in sections, preferably monotonically, particularly preferably continuously, from one end region 142 of the second busbar 128b to the other end region 144 of the second busbar 128b along the longitudinal direction 114 or X-direction of the electrochemical module 100.

In particular, it is provided that the transverse extent of the second busbar 128b increases from the one end region 142, which faces away from the second power connection of the electrochemical module 100, to a transition point 148 and remains substantially constant in the region from the transition point 148 to the other end region 144 of the second busbar 128b, which faces the second power connection of the electrochemical module 100. An edge 146 of the base body 136 of the second busbar 128b, facing away from the contact elements 152 of the second busbar 128b, runs in the region from one end region 142 to the transition point 148 obliquely to the longitudinal direction 114 or X-direction of the electrochemical module 100 and obliquely to the contacting direction 108 or Z-direction of the electrochemical module 100. In the region from the transition point 148 to the other end region 144, this edge 146 preferably runs substantially parallel to the longitudinal direction 114 or X-direction of the electrochemical module 100 and perpendicular to the contacting direction 108 or Z-direction of the electrochemical module 100.

Alternatively or additionally, it can be provided that the material thickness of the base body 136 of the second busbar 128b, that is to say the extension of the base body 136 along the transverse direction 118 or Y-direction of the electrochemical module 100, increases at least in sections, preferably monotonically, particularly preferably continuously, from one end region 142 of the second busbar 128b to the other end region 144 of the second busbar 128b along the longitudinal direction 114 or X-direction of the electrochemical module 100.

The second busbar 128b comprises, for each electrochemical cell 104 of the second cell group 126b of the electrochemical module 100, a second contact region 140 for electrically conductive connection to the respective second cell terminal of the respective electrochemical cell 104 of the second cell group 126b.

Each of the contact elements 152 of the second busbar 128b has a contact surface 150 at which the respective contact element 152 can be connected to the second cell terminal of one of the electrochemical cells 104 of the second cell group 126b, wherein this contact surface 150 is substantially perpendicular to the main surface 130b of the base body 136 of the second busbar 128b and perpendicular to the contacting direction 108 or Z-direction of the electrochemical module 100.

Furthermore, each of the contact elements 152 of the second busbar 128b comprises a second contact region 140, at which the respective contact element 152 can be connected - preferably in a materially bonded manner, in particular by welding, particularly preferably by laser welding - to the second cell terminal of one of the electrochemical cells 104 of the second cell group 126b, and an elastically and/or plastically deformable compensation region 154, via which the respective second contact region 140 is connected to the base body 136 of the second busbar 128b.

In the embodiment of an electrochemical module 100 shown in the drawing, it is provided that all second contact regions 140 of the second current busbar 128b, all compensation regions 154 of the second current busbar 128b and the base body 136 of the second current busbar 128b are formed integrally with one another.

Each of the busbars 128a, 128b is preferably formed by cutting out of a flat starting material and by at least partially forming the cut-out starting material.

The bus bars 128a and 128b are formed from an electrically conductive material, preferably a metallic material.

In particular, it can be provided that the busbars 128a and 128b are formed from an aluminum material. This can be pure aluminum or an aluminum alloy whose largest weight fraction consists of aluminum. As best seen in Fig. 5, the base bodies 136 of the first bus bar 128a and the second bus bar 128b are aligned substantially parallel to each other and parallel to the longitudinal direction 114 or X-direction of the electrochemical module 100 and spaced apart from each other along the transverse direction 118 or Y-direction of the electrochemical module 100.

All electrochemical cells 104 of the electrochemical module 100 are arranged - at least partially - between the opposing power connection rails 128a and 128b.

The electrochemical cells 104 of the first cell group 126a and the second cell group 126b are connected in series with the respective adjacent cell groups 126 of the electrochemical module 100, whose electrochemical cells 104 each follow one another in the longitudinal direction 114 or X-direction of the electrochemical module 100, by means of cell connectors 124, as shown by way of example in Figs. 6 and 7.

Through these cell connectors 124, the first cell terminals of the electrochemical cells 104 of a cell group 126 and the second cell terminals of the electrochemical cells 104 of an adjacent cell group 126 of the electrochemical module 100 are also connected in parallel to one another.

Each cell connector 124 thus serves as a parallel cell connector.

Each of the cell connectors 124 comprises a base body 156 which, viewed along the contact direction 108 or Z-direction of the electrochemical module 100, has a wave-like or zigzag shape. For contacting each first cell terminal of an electrochemical cell 104 of a neighboring cell group 126, the cell connector 124 comprises a first contact region 134, and for connecting to each second cell terminal of an electrochemical cell 104 of the other neighboring cell group 126, the cell connector 124 comprises a second contact region 140.

Each first contact region 134 is connected to the base body 156 of the cell connector 124 via an elastically and/or plastically deformable compensation region 154.

Likewise, every second contact region 140 of the cell connector 124 is connected to the base body 156 of the cell connector 124 via an elastically and/or plastically deformable compensation region 154.

As can be seen from Fig. 6, the compensation regions 154 can, for example, each have an S-shaped or Z-shaped cross-section.

All cell connectors 124 of the cell contacting system 120 are held on a carrier element 122, which is shown separately in Figs. 16 and 17.

The support element 122 is preferably plate-shaped.

The carrier element 122 has a passage opening 158 for each electrochemical cell 104 of the electrochemical module 100, through which the central first cell terminal of the respective electrochemical cell 104 can be contacted with a first contact area 134 of a cell connector 124 or the first current collecting bar 128a and the second cell terminal of the electrochemical cell 104 can be contacted with a second contact area 140 of another cell connector 124 or the second current collecting bar 128b. The carrier element 122 is formed from an electrically insulating material, in particular from a plastic material.

In the embodiment of an electrochemical module 100 shown in Figs. 2 to 17, the current collecting bars 128a and 128b have thus been relocated to two opposite outer sides of the electrochemical module 100, preferably to the longer outer sides of the substantially cuboid-shaped electrochemical module 100.

The main surfaces 130a, 130b of the base bodies 136 of the busbars 128a and 128b are aligned perpendicular to the contact surfaces 150 of the first contact regions 134 and the second contact regions 140 of the cell connectors 124.

The transverse extent of the busbars 128a and 128b, i.e. their extent along the contacting direction 108 or Z-direction of the electrochemical module 100, can correspond at least in sections to the total length of the electrochemical cells 104 along the contacting direction 108 or Z-direction of the electrochemical module 100.

Because the busbars 128a and 128b are not arranged in an additional plane above the cell connectors 124, the electrochemical module 100 has a lower overall height in the Z-direction.

Because the busbars 128a and 128b are arranged laterally on the electrochemical module 100, the cell terminals of the electrochemical cells 104 and the cell connectors 124 of the electrochemical module 100 are not covered by the busbars 128a or 128b. The electrically conductive connection of the electrochemical cells 104 to the cell connectors 124 and to the busbars 128a and 128b of the cell contact system 120 can therefore be established simultaneously, in a single step. Furthermore, in the event of a thermal runaway of one of the electrochemical cells 104 of the electrochemical module 100, the escaping hot gas can freely degas through the cell contact system 120 and be removed from the electrochemical module 100. This prevents the hot gas from accumulating in a plane above the cell connectors 124 and causing further thermal runaways of electrochemical cells 104.

Furthermore, the cell terminals of the electrochemical cells 104 of the electrochemical module 100 and the cell connectors 124 can be directly surrounded by the cooling medium of an immersion cooling system.

The current collecting bars 128a and 128b arranged laterally on the electrochemical module 100 can also be surrounded by a cooling medium—both on their outer side facing away from the electrochemical cells 104 and on their inner side facing the electrochemical cells 104. This increases the achievable cooling capacity and thus the performance of the electrochemical module 100.

To save material and weight, the geometry of the busbars 128a, 128b is adapted to the respective local current load and optimized according to the respective current density. This requires that, at least in sections, the electrically conductive cross-section of the busbars 128a, 128b decreases with increasing distance from the power connection of the electrochemical module 100 assigned to the respective busbar 128a, 128b. This can be achieved by tapering the base body 136 of the respective busbar 128a, 128b. The respective local current carrying capacity of the current busbars 128a, 128b can be determined both via the transverse extent, i.e. via the extent of the base body 136 of the respective current busbar 128a, 128b along the contact direction 108 or Z-direction of the electrochemical module 100, and/or via the respective local material thickness of the base body 136 of the Current busbar 128a, 128b, i.e. over the extension of the respective base body 136 along the transverse direction 118 or Y-direction of the electrochemical module 100.

The second embodiment of the electrochemical module 100 shown in Figs. 2 to 17 has a reduced overall height in the contacting direction 108 or Z-direction of the electrochemical module 100.

This design offers increased safety due to better removal of hot gases (better venting behavior).

The simultaneous contactability of the cell terminals of the electrochemical cells 104 of the electrochemical module 100 with the cell connectors 124 and with the busbars 128a, 128b improves the manufacturability and assembly of the cell contacting system 120 of the electrochemical module 100, thereby reducing production costs.

Because the electrochemical cells 104 and the cell connectors 124 are not covered by the busbars 128a, 128b, the flow of cooling medium around these elements of the electrochemical module 100 can be optimized, thereby improving the performance of the electrochemical module 100.

By adapting the local transverse extent and the local material thickness of the base body 136 of the busbars 128a, 128b, the total weight of the busbars 128a, 128b can be reduced particularly effectively.

Otherwise, the second embodiment of an electrochemical module 100 shown in Figs. 2 to 17 corresponds in terms of structure, function and method of manufacture to the first embodiment shown in Fig. 1, to the above description of which reference is made in this respect.

Claims

Patent claims 1. A cell contacting system for an electrochemical module (100) of an electrochemical device (102), wherein the electrochemical module (100) comprises a plurality of cell groups (126), each comprising a plurality of electrochemical cells (104), wherein each electrochemical cell (104) has a first cell terminal and a second cell terminal, wherein the cell terminals are contacted by means of electrically conductive contact regions (134, 140) which follow the respective cell terminal along a contacting direction (108), wherein the first cell terminals of the electrochemical cells (104) of a first cell group (126a) have the highest electrical potential during operation of the electrochemical module (100) and the second cell terminals of the electrochemical cells (104) of a second cell group (126b) have the lowest electrical potential during operation of the electrochemical module (100), and wherein the first cell terminals of the electrochemical cells (104) of the first cell group (126a) are electrically conductively connected to a first current collecting bar (128a) and the second cell terminals of the electrochemical cells (104) of the second cell group (126b) are electrically conductively connected to a second current collecting bar (128b), wherein the electrochemical cells (104) of the first cell group (126a) follow one another along a longitudinal direction (114) of the electrochemical module (100) and the electrochemical cells (104) of the second cell group (126b) follow one another along the longitudinal direction (114) of the electrochemical module (100), and at least one of the current collecting bars (128a, 128b) has a main surface (130a, 130b) which extends parallel to the longitudinal direction (114) of the electrochemical module (100), characterized in that the main surface (130a, 130b) of the at least one current collecting bar (128a, 128b) extends substantially parallel to the contacting direction (108) of the electrochemical cells (104) of the electrochemical module (100). 2. Cell contacting system according to claim 1, characterized in that both current collecting bars (128a, 128b) of the module (100) each have a main surface (130a, 130b) which extends parallel to the longitudinal direction (114) of the electrochemical module (100) and parallel to the contacting direction (108) of the electrochemical cells (104) of the electrochemical module (100). 3. Cell contacting system according to one of claims 1 or 2, characterized in that an electrically conductive cross-section of at least one of the current collecting bars (128a, 128b) taken perpendicular to the longitudinal direction (114) of the electrochemical module (100) increases at least in sections from one end region (142) to the other end region (144) of the relevant current collecting bar (128a, 128b). 4. Cell contacting system according to one of claims 1 or 2, characterized in that an electrically conductive cross-section of at least one of the current collecting bars (128a, 128b) taken perpendicular to the longitudinal direction (114) of the electrochemical module (100) increases monotonically from one end region (142) to the other end region (144) of the relevant current collecting bar (128a, 128b). 5. Cell contacting system according to one of claims 3 or 4, characterized in that a transverse extension of the at least one current collecting rail (128a, 128b) along the contacting direction (108) of the electrochemical cells (104) of the electrochemical module (100) increases at least in sections from one end region (142) to the other end region (144) of the respective current busbar (128a, 128b) along the longitudinal direction (114) of the electrochemical module (100). 6. Cell contacting system according to one of claims 3 to 5, characterized in that a material thickness of the at least one current collecting bar (128a, 128b) increases at least in sections from one end region (142) to the other end region (144) along the longitudinal direction (114) of the electrochemical module (100). 7. Cell contacting system according to one of claims 1 to 6, characterized in that the two current collecting rails (128a, 128b) comprise base bodies (136) which are aligned substantially parallel to one another and spaced apart from one another along a transverse direction (118) of the electrochemical module (100). 8. Cell contacting system according to one of claims 1 to 7, characterized in that at least one of the current collecting bars (128a, 128b) comprises at least one contact element (152) for electrically conductive connection to a cell terminal of an electrochemical cell (104) of a cell group (126a, 126b) adjacent to the current collecting bar (128a, 128b). 9. Cell contacting system according to claim 8, characterized in that the at least one contact element (152) has a contact surface (150) at which the contact element (152) can be connected to the cell terminal of an electrochemical cell (104), wherein the contact surface (150) is oriented substantially perpendicular to a main surface (130a, 130b) of the base body (136) of the current collecting bar (128a, 128b). 10. Cell contacting system according to one of claims 8 or 9, characterized in that the at least one contact element (152) comprises a contact region (134, 140) at which the contact element (152) can be connected to a cell terminal of an electrochemical cell (104), and an elastically and/or plastically deformable compensation region (154) via which the contact region (134, 140) is connected to the base body (136) of the current collecting bar (128a, 128b). 11. Cell contacting system according to claim 10, characterized in that the at least one contact region (134, 140), the at least one compensation region (154) and the at least one base body (136) of the respective current collecting bar (128a, 128b) are formed integrally with one another. 12. Cell contacting system according to one of claims 1 to 11, characterized in that at least one of the current collecting bars (128a, 128b) is formed by cutting out of a flat starting material and at least partially reshaping the cut-out starting material. 13. Cell contacting system according to one of claims 1 to 12, characterized in that at least one of the current collecting bars (128a, 128b) is formed from an aluminum material. 14. An electrochemical module of an electrochemical device (102), wherein the electrochemical module (100) comprises a plurality of cell groups (126), each comprising a plurality of electrochemical cells (104), and wherein the electrochemical module (100) comprises a cell contacting system (120) according to any one of claims 1 to 13. 15. Electrochemical module according to claim 14, characterized in that a plurality of electrochemical cells (104) of the electrochemical module (100) are arranged at least partially between the two current collecting bars (128a, 128b). 16. Electrochemical module according to one of claims 14 or 15, characterized in that no component of one of the current collecting bars (128a, 128b) completely covers one of the electrochemical cells (104) of the electrochemical module (100) - viewed in the contacting direction (108) of the electrochemical cells (104) of the electrochemical module (100).