Electrochemical cell stacking unit

Abstract

The invention comprises an electrochemical cell stacking unit (10) consisting of electrochemical cells which can be used, for example, as a fuel cell unit for the electrochemical generation of electrical energy from hydrogen and / or as an electrolysis cell unit for the generation of hydrogen and oxygen from electrical energy.

Description

The invention relates to an electrochemical cell stack unit / cell unit consisting of electrochemical cells, which can be used, for example, as a fuel cell unit for electrochemically generating electrical energy from hydrogen and / or as an electrolysis cell unit for generating hydrogen and oxygen from electrical energy.Prior ArtElectrochemical cell stack units are used in a wide variety of stationary and mobile applications.In electrochemical cell stack units, a multiplicity of individual electrochemical cells are arranged as cell stacks, also referred to as cell stacks, stacked one on top of the other, so that cell stack units can generally be considered as galvanic energy generators or energy converters which convert fuel and oxidizing agent continuously supplied at an anode and cathode into electrical energy by means of redox reactions and vice versa.For electrolysis and fuel cell, different technology variants stand for selection, in particular PEM electrolysis or PEM fuel cell, wherein PEM stands for proton exchange membrane, alternatively, AEM (anion exchange membrane), SOEC (solid oxide electrolysis cell) or AEL (liquid alkaline electrolysis).The electrochemical cell stack of a cell stack unit is usually bounded by two high-voltage contact plates, wherein the high-voltage contact plates each comprise a high-voltage terminal for tapping an output voltage.In this case, for example, the high-voltage contact plate with the positive high-voltage terminal is attached directly above the cell stack end and the high-voltage contact plate with the negative high-voltage terminal is attached directly below the cell stack end. It is also possible for the high-voltage contact plate with the negative high-voltage terminal to be mounted directly above and the high-voltage contact plate with the positive high-voltage terminal to be mounted directly below the cell stack end.In certain embodiments, the electrochemical cell stack can have changes in length due to operation, so that the distance between the two high-voltage terminals, in particular the distance between the positive high-voltage terminal and the negative high-voltage terminal, accordingly also varies according to the cell stack height.Since the distance between the high-voltage terminals is thus not constant, a very complex busbar assembly, which occupies installation space and is cost-intensive, is required in order to carry the current from the electrochemical cell stack.Disclosure of the InventionAccording to the first aspect of the invention, an electrochemical cell stack unit is provided. The electrochemical cell stack unit includes:a first end plate arrangement having a first end plate, a first insulator plate and a first high-voltage contact plate, wherein the first high-voltage contact plate has a first high-voltage terminal,a second end plate arrangement having a second end plate, a second insulator plate and a second high-voltage contact plate, wherein the second high-voltage contact plate has a second high-voltage terminal,an adjustment plate arrangement having a movable adjustment plate and a high-voltage current collector plate, wherein the adjustment plate arrangement is arranged between the first end plate arrangement and the second end plate arrangement,an electrochemical cell stack having a first lower end region and a second upper end region, wherein the electrochemical cell stack is expandable, in particular variable in length, along a longitudinal axis of the electrochemical cell stack, wherein the first lower end region is electrically connected to the first high-voltage contact plate and the second upper end region is electrically connected to the high-voltage current collector plate,a plurality of elastic members for applying pressure to the electrochemical cell stack and performing a stroke compensation due to a change in length of the electrochemical cell stack, the elastic members being disposed between the displacement plate assembly and the second end plate assembly,a plurality of tension members, wherein the plurality of tension members hold the first end plate assembly, the second end plate assembly, the adjusting plate assembly, the electrochemical cell stack, and the plurality of elastic members, wherein the plurality of tension members are in a tensioned state and the plurality of elastic members are in a compressed state,at least one electrical current guide for transmitting an electrical energy, in particular for transporting a high-voltage current, between the high-voltage current collector plate of the adjusting plate arrangement and the second high-voltage connection of the second high-voltage contact plate of the second end plate arrangement, wherein the at least one electrical current guide is arranged between the high-voltage current collector plate and the second high-voltage connection,wherein the at least one electric current conduction can be varied in length during the execution of the stroke compensation of the electrochemical cell stack.The core idea of the invention is therefore not to tap off the output voltage directly above the height-variable cell stack end, as in the prior art, but rather to conduct the current at the cell stack end further via the adjusting plate arrangement and via the at least one electrical current guide into the end plate arrangement, with the result that the output voltage can be tapped off in particular at the high-voltage contact plate of the end plate arrangement.By forwarding the current via the adjusting plate arrangement and the at least one electric current guide, in particular the second high-voltage terminal for tapping off the output voltage is displaced further upward, i.e. into the end plate arrangement above the electrochemical cell stack.In the context of the present invention, the first high-voltage terminal is preferably designed as a negative high-voltage terminal and the second high-voltage terminal is preferably designed as a positive high-voltage terminal. However, it is also possible that, conversely, the first high-voltage terminal is designed as a positive high-voltage terminal and the second high-voltage terminal is designed as a negative high-voltage terminal.The displacement of the positive high-voltage terminal into the end plate arrangement above the electrochemical cell stack has the particular advantage over the prior art that a constant distance between the two high-voltage terminals, in particular a constant distance between the positive high-voltage terminal and the negative high-voltage terminal, can be ensured.Thus, a very complex, space-consuming and cost-intensive assembly of a plurality of busbar systems is no longer required in order to carry the current from the electrochemical cell stack. The current can be conducted to the outside in a very simple manner via the high-voltage connections of the end plate arrangements.Further features and advantages of the invention are given below.In order to be able to conduct the current at the cell stack end further via the adjustment plate arrangement, it is preferably provided according to a first embodiment that the movable adjustment plate is designed to be electrically conductive in a contact region with the electrical current guide or comprises an electrically conductive material, wherein the contact region is fluid-tight and pressure-tight and electrically insulated from the external environment.The movable adjustment plate can also be embodied as non-electrically conductive, as is customary in the prior art, and cannot comprise an electrically conductive material.In order nevertheless to be able to pass on the current at the cell stack end via the latter, provision is preferably made, according to a second embodiment, for the at least one electrical current guide to be connected directly to a current collector of the high-voltage current collector plate in order to produce a high-voltage connection.The basic idea of the invention is to provide a simple and cost-effective electric current conduction for transmitting an electrical energy, in particular for transporting a high-voltage current, between the high-voltage current collecting plate of the adjusting plate arrangement and the second high-voltage connection of the second high-voltage contact plate of the second end plate arrangement.For this purpose, according to the invention, it is provided that the at least one electric current guide is arranged between the high-voltage current collector plate and the second high-voltage terminal.Furthermore, according to the invention, it is provided that the at least one electric current conduction can be varied in length during the execution of the stroke compensation of the electrochemical cell stack.For this purpose, the at least one electrical current guide is preferably designed as an electrically conductive high-voltage spring.Preferably, the at least one electric power supply is designed in a further exemplary embodiment as a flexible high-voltage power cable.Preferably, the at least one electric current guide is formed in a further exemplary embodiment as a multi-layer flexible high-voltage rail.Preferably, the at least one electric current guide is designed in a further exemplary embodiment as a deflectable high-voltage rail linkage.Preferably, the at least one electric current guide is designed as a flexible ground strip in a further exemplary embodiment.Further advantages, features and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can be essential to the invention individually or in any combination.The invention is explained in more detail below with reference to the accompanying drawings.The schematic figures show: FIG. 1 is a perspective view of an electrochemical cell stack unit according to a first embodiment of the present invention, FIG. 2 is a front view of an electrochemical cell stack unit according to the first embodiment of the present invention, including a plurality of high-voltage electrically conductive springs, FIG. 3 is a front view of an electrochemical cell stack unit according to the first embodiment of the present invention including a plurality of flexible high-voltage power cables, FIG. 4 is a front view of an electrochemical cell stack unit according to the second embodiment of the present invention with an electrically conductive high-voltage spring, FIG. 5 is a view of a first endplate assembly according to another embodiment of the present invention; and FIG. 6 is a view of a second end plate assembly according to another embodiment of the present invention.FIG. 1 is a perspective view of an electrochemical cell stack unit 10 according to a first embodiment of the present invention.The electrochemical cell stack unit 10 comprises a first end plate arrangement 40, a second end plate arrangement 60, a displacement plate arrangement 50, an electrochemical cell stack 20 having a first lower end region 21 and a second upper end region 22, and a plurality of clamping elements 90. Thus, the electrochemical cell stack unit 10 according to the invention can generally be considered as a galvanic energy generator or energy converter, which converts fuel and oxidizing agent continuously supplied at an anode and cathode into electrical energy by means of redox reactions and vice versa. In the figures shown, the electrochemical cell stack 20 is specifically designed as an FC cell stack which is constructed from individual electrochemical cells stacked one on top of the other.FIG. 2 is a front view of an electrochemical cell stack unit 10 according to the first embodiment of the present invention. The electrochemical cell stack 20 is expandable, in particular variable in length, along a longitudinal axis L of the electrochemical cell stack 20.The electrochemical cell stack 20 is constructed from individual electrochemical cells stacked one on top of the other, which can expand or contract again during working operation due to the action of pressure and heat. The expansion of the individual electrochemical cells in turn leads to an extension or shortening of the electrochemical cell stack 20.In other words, the electrochemical cell stack 20 has changes in length due to operation, which are compensated by a plurality of elastic elements 80.The elastic elements 80 serve in particular for applying pressure to the electrochemical cell stack 20 and for performing a stroke compensation as a result of the change in length of the electrochemical cell stack 20. In the figures shown, the elastic elements 80 are designed as tension springs, for example.As can be seen easily in FIG. 2, the electrochemical cell stack unit 10 further comprises a plurality of clamping elements 90.In the present invention, the tension members 90 are preferably configured as strap straps having attachment ends 95, the strap straps 90 each surrounding the first end plate assembly 40, and the attachment ends 95 of the strap straps 90 each connected to the second end plate assembly 60, such that the first end plate assembly 40, the second end plate assembly 60, the displacement plate assembly 50, the electrochemical cell stack 20, and the plurality of elastic members 80 are retained by the plurality of strap straps 90, with the plurality of strap straps 90 in a tensioned state and the plurality of elastic members 80 in a compressed state.The first end plate arrangement 40 comprises a first end plate 41, a first insulator plate 42 and a first high-voltage contact plate 43, wherein the first high-voltage contact plate 43 has a first high-voltage connection 44.The second end plate arrangement 60 comprises a second end plate 61, a second insulator plate 62 and a second high-voltage contact plate 63, wherein the second high-voltage contact plate 63 has a second high-voltage terminal 64.Within the scope of the present invention, the first high-voltage terminal 44 is preferably designed as a negative high-voltage terminal and the second high-voltage terminal 64 is preferably designed as a positive high-voltage terminal. However, it is also possible that, conversely, the first high-voltage terminal 44 is designed as a positive high-voltage terminal and the second high-voltage terminal 64 is designed as a negative high-voltage terminal.The distance between the first high-voltage terminal 44, in particular the positive high-voltage terminal, and the second high-voltage terminal 64, in particular the negative high-voltage terminal, is constant.In other words, the distance between the first high-voltage terminal 44 and the second high-voltage terminal 64 does not vary at any point in time during the working operation, in particular during the current transmission and the tapping of the output voltage.In the FIGS. 1, 2, 3, 4, 5, 6 to 7 shown, the high-voltage terminals 44, 64 are shown in a lateral region of the high-voltage contact plates 43, 63 for the purpose of illustration and for the purpose of better understanding. The high-voltage connections 44, 64 can in reality be mounted in any suitable region of the high-voltage contact plates 43, 63.The adjustment plate assembly 50 includes a movable adjustment plate 51 and a high voltage current collector plate 53, wherein the adjustment plate assembly 50 is disposed between the first end plate assembly 40 and the second end plate assembly 60.As can also be seen easily in FIG. 2, the electrochemical cell stack unit 10 further comprises at least one electrical current guide 70 for transmitting an electrical energy, in particular for transporting a high-voltage current, between the high-voltage current collecting plate 53 of the adjusting plate arrangement 50 and the second high-voltage terminal 64 of the second high-voltage contact plate 63 of the second end plate arrangement 60, wherein the at least one electrical current guide 70 is arranged above the high-voltage current collecting plate 53 and below the second high-voltage terminal 64, wherein the at least one electrical current guide 70 can be varied in length during the execution of the stroke compensation of the electrochemical cell stack 20.The first lower end portion 21 of the electrochemical cell stack 20 is electrically connected to the first high-voltage contact plate 43 and the second upper end portion 22 of the electrochemical cell stack 20 is electrically connected to the high-voltage current collecting plate 53.During the working operation of the electrochemical cell stack unit 10, a high-voltage electric current of high intensity is generated by the plurality of individual electrochemical cells of the electrochemical cell stack 20, which can be branched off from the first high-voltage terminal 44 and the second high-voltage terminal 64 for connection to external power-consuming devices. The insulator plates 42, 62 serve in particular to completely avoid an electrical loss from the high-voltage contact plates 43, 63 to the outside.In the prior art, the second high-voltage terminal 64, i.e. the positive high-voltage terminal, is mounted directly on the second upper end region 22 of the electrochemical cell stack 20. Since the electrochemical cell stack 20 has changes in length due to operation, the distance between the two high-voltage terminals 44, 64 accordingly also varies according to the cell stack height. The electric current guide 70 according to the invention is intended to eliminate this problem.The core idea of the invention is not to tap off the output voltage directly at the second upper end region 22 of the electrochemical cell stack 20, as in the prior art, but rather to conduct the current at the second upper end region 22 of the electrochemical cell stack 20 further via the adjusting plate arrangement 50 and via the at least one electrical current guide 70 into the second end plate arrangement 60, with the result that the output voltage can be tapped off in particular at the second high-voltage connection 64 of the second high-voltage contact plate 61 of the second end plate arrangement 60.By passing on the current via the adjusting plate arrangement 50 and the at least one electrical current guide 70, the positive high-voltage terminal 64 is in particular displaced further upward, i.e. into the second high-voltage contact plate 61 of the second end plate arrangement 60 above the electrochemical cell stack 20, in order to pick off the output voltage. The displacement of the positive high-voltage terminal 64 has the particular advantage over the prior art that a constant distance between the two high-voltage terminals 44, 64, in particular a constant distance between the positive high-voltage terminal 64 and the negative high-voltage terminal 44, can be ensured.According to the invention, at least one electric current guide 70 is provided. Preferably, a plurality of electric current guides 70 are provided.In FIG. 2, a plurality of electric current guides 70 are provided, which are designed as electrically conductive high-voltage springs 71.The high-voltage electrically conductive springs 71 differ from the elastic elements 80 designed as tension springs.The electrically conductive high-voltage springs 71 are suitable in particular for static or dynamic electrical applications. The electrically conductive high-voltage springs 71 enable a constant and reliable high-voltage connection even in the event of impacts and vibrations. The high voltage electrically conductive springs 71 effectively handle high, medium and low current over a long period of time with minimal heat build-up in a compact space.In order to be able to conduct the current at the second upper end region 22 of the electrochemical cell stack 20 further via the adjustment plate arrangement 50, it is preferably provided according to a first embodiment that the movable adjustment plate 51 is designed to be electrically conductive in a contact region 55 with the electrical current guide 70 or comprises an electrically conductive material, wherein the contact region 55 is electrically insulated from the external environment.It is possible for the contact region 55 to have at least one high-voltage passage for carrying through the at least one electric current guide 70. Via the high-voltage passage, for example, a direct high-voltage connection can be established between the electrical current guide 70 and the high-voltage current collector plate 53 of the adjusting plate arrangement 50.FIG. 3 is a front view of an electrochemical cell stack unit 10 according to the first embodiment of the present invention including a plurality of flexible high-voltage power cables 72.In this embodiment, no more expensive and high-quality electrically conductive high-voltage springs 71 are required in order to be able to conduct the current at the second upper end region 22 of the electrochemical cell stack 20 further via the adjusting plate arrangement 50. The flexible high-voltage power cables 72 can be easily guided within the already inserted elastic elements 80, i.e. the tension springs, or laterally parallel to the tension springs.The flexible high-voltage power cables 72 have very good electrical conductivity. In addition, the flexible high-voltage power cables 72 have very good insulation in regions in order to be able to be guided within the elastic elements 80 already used.FIG. 4 shows a front view of an electrochemical cell stack unit 10 according to the second embodiment of the present invention with an electrically conductive high-voltage spring 71.In this embodiment, the movable adjustment plate 51, as is customary in the prior art, is embodied to be non-electrically conductive and does not comprise any electrically conductive material. The elastic elements 80 likewise have no electrically conductive function and are designed as conventional tension springs.In order to be able to transfer the current at the second upper end region 22 of the electrochemical cell stack 20 nevertheless, it is provided according to the second embodiment that the at least one electrical current guide 70, in particular the electrically conductive high-voltage spring 71, is directly connected to a current collector 54 of the high-voltage current collector plate 53 for producing a high-voltage connection.In order to completely avoid an electrical loss from the high-voltage current collector plate 53 to the outside, the adjusting plate arrangement 50 has a third insulator plate 52.In the figures shown, for purposes of illustration and for better understanding, the electric current guide 70 is guided in a lateral region of the electrochemical cell stack 20. The electric current guide 70 can in fact be guided in any suitable region.It is also possible that the electric current guide 70 according to the invention is designed in a further embodiment as a multi-layer flexible high-voltage rail 73.Such a multilayer flexible high-voltage rail 73 can consist, for example, of a plurality of individual copper current rails which are deformable, in particular bendable. As a result, the multi-layer flexible high-voltage rail 73 is very well suited for high dynamic loads and high temperatures. At the same time, the multi-layer flexible high-voltage rail 73 is very well suited for compensating system movements, in particular for compensating the stroke of the electrochemical cell stack 20 during working operation.The multi-layer flexible high-voltage rail 73 is also very light and has a very good electrical conductivity. In addition, the flexible high-voltage rail 73 has, in some regions, very good insulation with respect to the external environment.It is also possible that the electric current guide 70 according to the invention is designed in a further embodiment as a deflectable high-voltage rail linkage 74.Such a deflectable high-voltage rail linkage 74 can consist, for example, of electrically conductive and insulated rods, hinges and ball joints. The rods may be formed, for example, from copper, aluminum or another electrically conductive material.The rods are very robust and are very well suited for precise translatory movements under high dynamic loads and high temperatures.The deflectable high-voltage rail linkage 74 is thus likewise very well suited for the stroke compensation of the electrochemical cell stack 20 during the working operation.In a further embodiment, the electric current guide 70 according to the invention can be designed as a flexible ground strip 75. Such a flexible mass strap 75 can have, for example, a flat cross-sectional profile and consist of a braid of a plurality of thin copper wires or a packet of thin copper sheets. The flexible ground strip 75 has a very good electrical conductivity and, in some areas, a very good insulation.In the illustrated FIGS. 1, 2, 3 to 4, the end plates 41, 61, the insulator plates 42, 62, and the high-voltage contact plates 43, 63 are formed as separate components.In a further embodiment, the insulator plates 42, 62 and the high-voltage contact plates 43, 63 are integrated in the end plates 41, 61, such that the end plate arrangements 40, 60 each consist of only one plate. Such an individual plate can be, for example, a plate formed from a plurality of different materials, which plate has an electrical conductivity and electrical insulation in regions.In a further embodiment, the insulator plate 52 and the high-voltage current collector plate 53 are integrated in the movable adjustment plate 51, so that the adjustment plate arrangement 50 consists of only one plate.FIG. 5 shows a view of a first endplate assembly 40 according to another embodiment of the present invention. In the illustrated first end plate assembly 40, the first end plate 41, the first insulator plate 42 and the first high-voltage contact plate 43 are integrated, so that the illustrated first end plate assembly 40 consists of only one plate.The illustrated first end plate arrangement 40 has a plurality of openings 45 for the connection points of the connection lines (media feed, discharge).As can be seen easily in FIG. 5, the first high-voltage terminal 44, that is to say the negative high-voltage terminal, is provided in a lateral edge region. However, the first high-voltage terminal 44 may be mounted in any suitable region of the illustrated first end plate assembly 40.FIG. 6 shows a view of a second endplate assembly 60 according to another embodiment of the present invention.In the illustrated second end plate assembly 60, the second end plate 61, the second insulator plate 62, and the second high-voltage contact plate 63 are integrated, so that the illustrated second end plate assembly 60 is made of only one plate.In comparison with the first end plate arrangement 40 shown in FIG. 5, the second end plate arrangement 60 shown in FIG. 6 does not have any openings for the connection points of the connection lines (media feed, discharge).As can be seen easily in FIG. 6, the second high-voltage terminal 64, i.e. the positive high-voltage terminal, is provided in a corresponding lateral edge region. However, the second high-voltage terminal 64 may be mounted in any suitable region of the illustrated second end plate assembly 60.The first high-voltage terminal 44 and the second high-voltage terminal 64 can be arranged identically to one another in an analogous manner. The first high-voltage terminal 44 and the second high-voltage terminal 64 may also be arranged at different positions independently of one another.

Claims

Electrochemical cell stack unit (10) comprising: - a first end plate arrangement (40) having a first end plate (41), a first insulator plate (42) and a first high-voltage contact plate (43), wherein the first high-voltage contact plate (43) has a first high-voltage terminal (44), - a second end plate arrangement (60) having a second end plate (61), a second insulator plate (62) and a second high-voltage contact plate (63), wherein the second high-voltage contact plate (63) has a second high-voltage terminal (64), - an adjustment plate arrangement (50) having a movable adjustment plate (51) and a high-voltage current collector plate (53), wherein the adjustment plate arrangement (50) is arranged between the first end plate arrangement (40) and the second end plate arrangement (60), an electrochemical cell stack (20) having a first lower end region (21) and a second upper end region (22), wherein the electrochemical cell stack (20) is expandable, in particular variable in length, along a longitudinal axis (L) of the electrochemical cell stack (20), wherein the first lower end region (21) is electrically connected to the first high-voltage contact plate (43) and the second upper end region (22) is electrically connected to the high-voltage current collecting plate (53), - a plurality of elastic elements (80) for applying pressure to the electrochemical cell stack (20) and for carrying out a stroke compensation as a result of a change in length of the electrochemical cell stack (20), wherein the elastic elements (80) are arranged between the adjusting plate arrangement (50) and the second end plate arrangement (60), - a plurality of clamping elements (90), wherein the plurality of clamping elements (90) holds the first end plate arrangement (40), the second end plate arrangement (60), the adjusting plate arrangement (50), the electrochemical cell stack (20) and the plurality of elastic elements (80), wherein the plurality of clamping elements (90) are in a clamped state and the plurality of elastic elements (80) are in a compressed state, - at least one electric current guide (70) for transmitting an electric energy, in particular for transporting a high-voltage current, between the high-voltage current collecting plate (53) of the adjusting plate arrangement (50) and the second high-voltage terminal (64) of the second high-voltage contact plate (63) of the second end plate arrangement (60), wherein the at least one electric current guide (70) is arranged between the high-voltage current collector plate (53) and the second high-voltage terminal (64), - wherein the at least one electric current guide (70) can be varied in length during the execution of the stroke compensation of the electrochemical cell stack (20).Electrochemical cell stack unit (10) according to Claim 1, characterized in that the movable adjustment plate (51) is designed to be electrically conductive in a contact region (55) with the at least one electrical current guide (70) or comprises an electrically conductive material, wherein the contact region (55) is electrically insulated from the external environment.Electrochemical cell stack unit (10) according to Claim 1, characterized in that the at least one electrical current guide (70) is connected directly to a current collector (54) of the high-voltage current collector plate (53) for producing a high-voltage connection.Electrochemical cell stack unit (10) according to one of the preceding claims, characterized in that the at least one electrical current guide (70) is designed as an electrically conductive high-voltage spring (71).Electrochemical cell stack unit (10) according to one of the preceding claims 1 to 3, characterized in that the at least one electrical power supply (70) is designed as a flexible high-voltage power cable (72).Electrochemical cell stack unit (10) according to one of the preceding claims 1 to 3, characterized in that the electrical current guide (70) is formed as a multi-layer flexible high-voltage rail (73).Electrochemical cell stack unit (10) according to one of the preceding claims 1 to 3, characterized in that the electrical current guide (70) is designed as a deflectable high-voltage rail linkage (74).Electrochemical cell stack unit (10) according to one of the preceding claims 1 to 3, characterized in that the electrical current guide (70) is designed as a flexible ground strip (75).

Images