Clamping device and method for clamping a stack of electrochemical units

Abstract

To create a clamping device for clamping a stack of electrochemical units arranged along a stacking direction and between clamping plates, wherein the clamping device comprises at least one clamping band system, each clamping band system comprising at least one clamping band having a first clamping band end and a second clamping band end, and at least one locking system for connecting a first clamping band end of a clamping band to a second clamping band end of the same clamping band or of another clamping band, wherein the locking system comprises a first locking element in contact with a first clamping band end, a second locking element in contact with a second clamping band end, and a clamping element for clamping the first locking element and the second locking element,In order to reduce or preferably completely avoid unwanted transverse force loading of the clamping element of at least one locking system of at least one tension band system of the clamping device during the clamping of the stack of electrochemical units, it is proposed that the first locking element and / or the second locking element have a substantially flat contact surface with which the respective locking element bears against a section of the tension band guided around the respective locking element and / or against one of the clamping plates during the tightening of the clamping element.

Description

[0001] The present invention relates to a clamping device for clamping a stack of electrochemical units arranged in a stacking direction and positioned between clamping plates, wherein the tensioning device comprises at least one tensioning band system, wherein each tensioning band system comprises at least one tensioning band having a first tensioning band end and a second tensioning band end, and at least one locking system for connecting a first tensioning band end of a tensioning band to a second tensioning band end of the same tensioning band or of another tensioning band, wherein the locking system each has a first locking element which is in contact with a first tension band end, a second locking element which is in contact with a second tension band end, and includes a tensioning element for tensioning the first locking element and the second locking element.

[0002] The tensioning of the stack of electrochemical units, which are part of an electrochemical device, by means of tension bands serves to provide sufficient compression of the electrochemical units in their electrochemically active areas.

[0003] The tension of the stack of electrochemical units is therefore relevant for the performance of the electrochemical device and must be within a defined tension force range.

[0004] For this purpose, at least one tension band of a tension band system is placed over the clamping plates, which limit the stack of electrochemical units at its two ends.

[0005] The clamping plates distribute the clamping force applied via the at least one clamping band over the electrochemically active areas of the electrochemical units.

[0006] One goal of clamping using the clamping device is to achieve the most homogeneous force distribution possible in the electrochemically active area of ​​the electrochemical units of the stack.

[0007] Since a single tension band is often not wide enough to cover a clamping plate across its entire width, several tension band systems, preferably three or more, are usually used.

[0008] It may be provided that each tension band system comprises only one tension band, which has two tension band ends that are tensioned together by means of a locking system.

[0009] Alternatively, it can also be provided that a tension band system has several tension bands, the ends of which are tensioned together via a corresponding number of locking systems.

[0010] The locking systems can be in contact with the clamping plates at the ends of the stack of electrochemical units.

[0011] Alternatively, the locking systems can be arranged laterally next to the stack of electrochemical units, spaced apart from the clamping plates.

[0012] The clamping force of the stack of electrochemical units is usually torque-controlled via a defined tightening torque of the screw connection, by means of which the locking elements of a locking system are connected to each other.

[0013] To achieve tension between the locking elements, there are different designs of locking systems.

[0014] For example, a locking system may comprise two locking elements designed as round bolts, each with a through hole. One of the through holes may be provided with an internal thread into which an external thread of a clamping screw, forming part of the clamping element, engages.

[0015] The locking elements are each enclosed by one end of the same tension band or by two different tension bands.

[0016] The ends of the tensioning straps can take the form of a loop, a tab, or a hook. Furthermore, it may be provided that a tab or hook is attached to a tensioning strap end via another element.

[0017] The locking elements of a locking system can be screwed together by tightening a tension screw.

[0018] Each tension band system can be pre-assembled and fitted over the stack of electrochemical units, including the clamping plates, with the locking system already closed.

[0019] Alternatively, it may be provided that the opened tensioning band system is placed around the stack of electrochemical units, including the clamping plates, and then the locking system or locking systems of the tensioning band system are closed by tightening the clamping element.

[0020] The locking elements, which are each enclosed by a tension band end, are often equipped with a locking device for assembly, since there should be play between the respective locking element and the tension band end assigned to the locking element in order to allow free rotation of the locking element in the tension band end - which is designed, for example, as a tension band loop.

[0021] Such a locking mechanism can, for example, be formed in the form of a step at a lateral end of the locking element. Preferably, a locking mechanism is provided at each lateral end of the locking element.

[0022] The diameter of the locking device is preferably larger than the diameter of the tension band loop encircling the respective locking element. In this case, each locking device defines a lateral edge of the tension band placed around the locking element.

[0023] Another way to create a loss-proof mechanism is to increase the diameter of the locking element by creating a recess in a tab of the tension band.

[0024] Since the locking elements, designed as round bolts, can rotate freely within the tension band loop of their respective end when the stack of electrochemical units is tensioned, the locking elements – especially with their anti-removal devices – roll down the surface of an adjacent clamping plate. This rolling is caused by the application of a force between the edges of the anti-removal devices of the locking element, which protrude beyond the tension band, and the adjacent clamping plate.

[0025] In the force-free state of the locking device, the through holes in the locking elements of the locking system, through which the clamping element extends, are ideally coaxial to each other.

[0026] As the locking elements roll during the clamping of the stack of electrochemical units, the through holes, which are ideally coaxial in their unloaded state, tilt relative to each other. This results in an increasing shear force component being introduced into the clamping element, particularly into a clamping screw, as the clamping force is applied to the locking system during the clamping process. This shear force component leads to an increase in the tightening torque required to achieve the defined clamping force of the stack of electrochemical units.

[0027] The shear force component generated by the rolling of the locking elements is difficult to determine in advance and depends on various boundary conditions, such as the coefficient of static friction between the clamping plate and the locking element's retention device and / or the coefficient of static friction between the clamping plate and the clamping band. For locking elements with an internal thread, the friction between the locking screw and the thread flanks of the internal thread can also have a significant influence.

[0028] The tightening torque applied during the clamping process therefore only partially tightens the screw connection of a locking system, but also serves to compensate for the shear force component acting on the screw connection of the locking elements. This results in only a portion of the predefined clamping force actually being introduced into the ends of the clamping bands that are connected by the locking system.

[0029] This means that the predefined clamping force of the stack of electrochemical units is not achieved, which can lead to the compression of the electrochemical units of the stack of electrochemical units being too low.

[0030] Furthermore, the occurrence of the shear force component during the tensioning of the locking system leads to a significantly increased load on the tensioning element even after the tensioning process. This element is subjected not only to axial and torsional stress, but also to multiaxial stress. The tensioning element, particularly a tensioning screw, must therefore be considerably larger and require more installation space than would be necessary without the presence of the shear force component.

[0031] The present invention is based on the objective of creating a clamping device of the type mentioned at the outset, in which an unwanted transverse force load on the clamping element of at least one closure system or at least one tension band system of the clamping device is reduced or preferably completely avoided during the clamping of the stack of electrochemical units.

[0032] This problem is solved according to the invention in a clamping device with the features of the preamble of claim 1 by the fact that the first locking element and / or the second locking element has a substantially flat contact surface with which the respective locking element rests against a section of the clamping band guided around the respective locking element and / or against one of the clamping plates during the tightening of the clamping element.

[0033] The present invention is therefore based on the concept of preventing the rolling of at least one of the locking elements of a locking system on an adjacent clamping plate by a geometric change in the shape of the locking element, thereby creating a flat contact surface.

[0034] Preferably, the introduction of a clamping force from the relevant locking element via its at least one locking device directly into the adjacent clamping plate is also prevented.

[0035] Due to the presence of the flat contact surface, the at least one locking element slides directly or indirectly over the tensioning band placed around the locking element on the adjacent clamping plate during the clamping process, thus preventing the locking element from rolling off the clamping plate and therefore preventing the through holes in the two locking elements of a locking system from tilting relative to each other.

[0036] It may be provided that the flat mounting surface extends from a first lateral end of the relevant locking element to a second lateral end of the relevant locking element.

[0037] In this case, the flat contact surface extends over the entire width (i.e., the extension perpendicular to the longitudinal direction of the tension band) of the relevant locking element, including one or more locking devices of the locking element.

[0038] Alternatively, it can be provided that the flat mounting surface only includes a flat area of ​​a lateral surface of an anti-rotation device of the locking element or flat areas of the lateral surfaces of two anti-rotation devices of the locking element.

[0039] In this case, a deflection section of the locking element located between the anti-rotation devices can have a round cross-section, a polygonal cross-section, or any other geometric shape.

[0040] In a particular embodiment of the invention, the first locking element and / or the second locking element each comprise at least one anti-capture device, which has a cylindrical surface that includes a flat area. During tightening of the clamping element, the flat area of ​​the cylindrical surface of the at least one anti-capture device rests against one of the clamping plates. This effectively prevents the clamping element from rolling off the clamping plate and thus prevents the through holes in the two locking elements of a locking system from tilting relative to each other.

[0041] Alternatively or additionally, the problem underlying the invention in a clamping device with the features of the preamble of claim 1 is also solved according to the invention by the fact that at least one end of the clamping band is guided around one of the locking elements in such a way that the locking element in question is not in contact with a clamping plate adjacent to the locking element during the tightening of the clamping element.

[0042] In this embodiment of the invention, the diameter of the locking device is reduced so that it does not exceed the outer diameter of the tension band loop around the locking element. The inner diameter of the tension band loop remains smaller than the outer diameter of the locking device. When the locking elements of the locking system are tensioned together, only the tension band slides on the surface of the clamping plate, while the locking element enclosed by the tension band, including its at least one locking device, has no contact with the clamping plate. In this way, the transmission of a clamping force from the locking element, via its at least one locking device, directly into the clamping plate is effectively prevented.

[0043] It may be provided that at least one of the locking elements comprises a deflection section around which the tension band end assigned to the locking element is guided, and comprises at least one loss-proof device, wherein a radius R of the loss-proof device exceeds a radius r of the deflection section by a difference Δ which is smaller than a material thickness s of the tension band in the area of ​​the relevant tension band end.

[0044] The deflection section can essentially be cylindrical.

[0045] Preferably, in this embodiment, the first locking element and / or the second locking element comprises two locking devices which are spaced apart from each other by the deflection section of the respective locking element.

[0046] Alternatively or additionally, the problem underlying the invention in a clamping device with the features of the preamble of claim 1 is also solved according to the invention by the fact that the clamping element of at least one closure system of at least one clamping band system comprises a clamping screw and a clamping nut arranged on the clamping screw.

[0047] In this case, preferably none of the locking elements of the locking system have an internal thread. Instead, the locking system is tightened by tightening the clamping nut relative to the clamping screw. While this can, in principle, cause the through holes of the locking elements to tilt relative to each other, thus applying a shear force component to the clamping screw, the tightening can be achieved via the clamping nut. This means that the tightening torque between the clamping nut and the clamping screw is independent of any deflection of the clamping screw in the area between the locking elements of the locking system, which occurs due to the shear force component.

[0048] Alternatively or additionally, the problem underlying the present invention is also solved according to the invention in a clamping device with the features of the preamble of claim 1 by the fact that the clamping element of at least one closure system of at least one clamping band system is guided through a through hole in the first closure element, wherein the smallest diameter of the through hole exceeds the largest outer diameter of the clamping element in the area of ​​the through hole by at least 5%, preferably by at least 10%.

[0049] Increasing the diameter of the through-hole in the locking element creates more clearance between the shank of the tensioning screw and the boundary wall of the through-hole in the locking element. This reduces friction between the tensioning screw and the locking element, allowing a greater proportion of the tightening torque of the tensioning screw to be used for tensioning the ends of the tension bands guided around the locking elements of the locking element.

[0050] Alternatively or additionally, the problem underlying the present invention is also solved according to the invention in a clamping device with the features of the preamble of claim 1 by the fact that the clamping element of at least one closure system of at least one clamping band system is guided through a through hole in the second closure element, wherein the smallest diameter of the through hole exceeds the largest outer diameter of the clamping element in the area of ​​the through hole by at least 5%, preferably by at least 10%.

[0051] In a preferred embodiment of the invention, it is provided that the clamping element of at least one closure system of at least one tension band system comprises a clamping screw which engages in an internal thread which is arranged in one of the closure elements.

[0052] Furthermore, it is preferably provided that at least one of the tension band ends forms a tension band loop in which the tension band is guided back onto itself and fixed to a fixing section of the tension band.

[0053] Furthermore, it is advantageous if at least one of the tension band ends has at least one passage opening, preferably at least two passage openings, through which the tensioning element passes.

[0054] It is preferably provided that at least one clamping element of at least one locking system of at least one tensioning band system comprises a clamping screw which has an actuation area, and / or a clamping nut which has an actuation area, wherein the passage opening through which the clamping element passes in the clamped state of the clamping device is arranged between the actuation area of ​​the clamping screw or the clamping nut on the one hand and the locking element of the locking system that is closest to the actuation area on the other hand.

[0055] An actuating tool, such as a screwdriver or wrench, can be applied to the actuating area of ​​the clamping screw or clamping nut in order to rotate the clamping screw or clamping nut around its longitudinal central axis.

[0056] The present invention further relates to a method for clamping a stack of electrochemical units that follow one another along a stacking direction and are arranged between clamping plates, by means of a clamping device, wherein the clamping device comprises at least one clamping band system, wherein each clamping band system has at least one clamping band having a first clamping band end and a second clamping band end, and comprising at least one locking system for connecting a first tension band end of a tension band to a second tension band end of the same tension band or of another tension band, wherein the locking system each has a first locking element which is in contact with a first tension band end, a second locking element which is in contact with a second tension band end, and includes a tensioning element for tensioning the first locking element and the second locking element.

[0057] The present invention is based on the further objective of creating a method for clamping a stack of electrochemical units in which tilting of through holes in the closure elements of a closure system relative to each other is prevented or at least reduced during the execution of a screw connection between the closure elements of a closure system of a tension band system of the clamping device during the clamping of the stack of electrochemical units of an electrochemical device.

[0058] This problem is solved in a method for clamping a stack of electrochemical units with the features of the preamble of claim 15 according to the invention in that the locking elements, the tension band ends and the clamping element are designed such that when the clamping element is tightened, essentially no transverse force component directed transversely to a longitudinal direction of the clamping element acts on the clamping element from the locking elements.

[0059] The method according to the invention is preferably carried out using a clamping device according to the invention for clamping a stack of electrochemical units.

[0060] The clamping device according to the invention for clamping a stack of electrochemical units is preferably used according to the method according to the invention for clamping a stack of electrochemical units.

[0061] Specific embodiments of the method according to the invention have already been explained above in connection with specific embodiments of the clamping device according to the invention.

[0062] The clamping device according to the invention is particularly suitable for clamping a stack of electrochemical units which are part of an electrochemical device.

[0063] The electrochemical device can be designed, for example, as a fuel cell device (in particular a polymer electrolyte membrane fuel cell device), as an electrolyzer or as an electrochemical compressor.

[0064] Further features and advantages of the invention are the subject of the following description and the graphic representation of exemplary embodiments.

[0065] The drawings show: Fig. 1 a schematic side view of a first embodiment of an electrochemical device comprising a stack of electrochemical units arranged along a stacking direction and between two clamping plates, and a clamping device for clamping the stack of electrochemical units between the clamping plates, wherein the clamping device comprises one or more clamping band systems, wherein each tension band system comprises a tension band having a first tension band end and a second tension band end, and a locking system for connecting the first tension band end of the tension band to the second tension band end of the same tension band, wherein the locking system each has a first locking element which is in contact with the first tension band end, a second locking element which is in contact with the second end of the tension band, and a tensioning element for tensioning the first locking element and the second locking element comprises, wherein the first locking element and the second locking element each have a substantially planar contact surface with which the locking element indirectly rests against one of the clamping plates over a section of the clamping band during the tightening of the clamping element, wherein the planar contact surface extends from a first lateral end of the locking element to a second lateral end of the locking element, with the viewing direction perpendicular to the stacking direction and perpendicular to a common direction of rotation of all clamping band systems of the clamping device, wherein the common direction of rotation is directed from a first clamping band end of a first clamping band system to a second clamping band end of the same clamping band system, which is clamped to the first clamping band end by means of the clamping element; Fig. 2 a schematic longitudinal section through a locking system of a tension band system of the electrochemical device Fig. 1, parallel to a longitudinal median plane of the locking system aligned parallel to the stacking direction and parallel to the common direction of rotation; Fig. 3 a perspective view of a locking system of the electrochemical device resting against a clamping plate from the Fig. 1 and Fig. 2; Fig. 4 a perspective view of a locking system of a tension band system in a second embodiment of an electrochemical device, in which the first locking element and the second locking element each have a locking device for the tension band at their lateral ends and a substantially planar contact surface is provided on the locking devices, while a deflection section of the respective locking element located between the locking devices, around which the respective tension band end is guided, has a circular cross-section; Fig. 5 a partially cutaway view of one of the locking elements of a locking system of a tension band system in a third embodiment of an electrochemical device, in which the tension band end associated with the locking element is guided around the locking element in such a way that the locking element is not in contact with a clamping plate adjacent to the locking element during the tightening of the tensioning element, wherein the locking element comprises a deflection section around which the tension band end associated with the locking element is guided, and a locking device at each of its two lateral ends, wherein a radius R of the locking device exceeds the radius r of the deflection section of the locking element by a difference Δ which is smaller than a material thickness s of the tension band in the region of the tension band end; Fig. 6 a schematic longitudinal section through the locking system of a tension band system of the electrochemical device Fig. 5, along line 6 - 6 in Fig. 5; Fig. 7 a schematic longitudinal section through a locking system of a tensioning band system of a tensioning device for clamping a stack of electrochemical units in a fourth embodiment of an electrochemical device, in which each of the tensioning band systems comprises a tensioning element having a tensioning screw and a tensioning nut arranged on the tensioning screw, wherein a shank of the tensioning screw extends through a first through-hole in a first locking element and through a second through-hole in a second locking element of the locking system, wherein the locking screw is guided in both through-holes with such a large clearance that an external thread of the tensioning screw does not come into contact with the first locking element or the second locking element; and Fig. 8 a schematic longitudinal section through a locking system of a tension band system of a tensioning device for clamping a stack of electrochemical units in a fifth embodiment of an electrochemical device, in which the clamping element comprises a clamping screw whose external thread engages in an internal thread on one of the locking elements, while the clamping screw is guided in a through hole of the other locking element with so much play that the shank of the clamping screw does not come into contact with the boundary wall of this through hole when the clamping screw is tightened.

[0066] Identical or functionally equivalent elements are designated with the same reference symbols in all figures.

[0067] One in the Fig. The first embodiment of an electrochemical device, designated as a whole by 100, shown in Figures 1 to 3, comprises a stack 102 of electrochemical units 104 which follow one another along a stacking direction 106 and are arranged between two clamping plates 108.

[0068] The electrochemical device 100 can, for example, be designed as a fuel cell device, as an electrolyzer or as an electrochemical compressor.

[0069] Furthermore, the electrochemical device 100 comprises a clamping device 110 for clamping the stack 102 of the electrochemical units 104 between the clamping plates 108, wherein the clamping device 110 comprises one or more clamping band systems 112, preferably two or more clamping band systems 112, in particular three or more clamping band systems 112, and especially preferably four or more clamping band systems 112.

[0070] Each tension band system 112 comprises a tension band 114, which has a first tension band end 116 and a second tension band end 118.

[0071] Each of the tension band ends 116 and 118 can, for example, be designed as a tension band loop 120, wherein an end piece 122 of the respective tension band 114 is returned to a respective assigned fixing section 124 of the respective tension band 114, preferably lying substantially flat against the fixing section 124 and is fixed to the fixing section 124, preferably by a material bond.

[0072] This fixing of the end piece 122 to the respective assigned fixing section 124 of the tension band 114 can be done, for example, by gluing, soldering or welding.

[0073] During the Fig. In the embodiment of an electrochemical device 100 shown in Figures 1 to 3, each tension band system 112 comprises a locking system 126 for connecting the first tension band end 116 of the tension band 114 with the second tension band end 118 of the same tension band 114.

[0074] The locking system 126 comprises a first locking element 128, which is in contact with the first tension band end 116, a second locking element 130, which is in contact with the second tension band end 118, and a tensioning element 132 for tensioning the first locking element 128 and the second locking element 130.

[0075] In the illustrated embodiment, the clamping element is designed as a clamping screw 134.

[0076] Each tensioning screw 134 comprises a screw head 136, which may, for example, include an actuating end 138 of the tensioning screw 134 and a thinner head area 140 of the tensioning screw 134, and a shaft area 142, which is provided at least partially with an external thread 144.

[0077] How best to get from the Fig. 2 and Fig. As can be seen in Figure 3, the locking elements 128 and 130 of the locking system 126 in this embodiment of a clamping device 110 are preferably designed as round bolts 146, each of which has a through hole 148 extending in the radial direction of the respective round bolt 146 and arranged axially in the center.

[0078] The shaft area 142 of the tensioning screw 134 extends through both through holes 148.

[0079] The through-hole 148a in the first locking element 128 of the locking system 126 is designed such that its diameter is slightly larger than the outer diameter of the external thread 144 of the clamping screw 134, so that the clamping screw 134 is guided with minimal play in the through-hole 148a of the first locking element 128.

[0080] The through-hole 148b in the second locking element 130, however, is provided with an internal thread 150, which is designed to be complementary to the external thread 144 of the clamping screw 134, so that the external thread 144 of the clamping screw 134 engages in the internal thread 150 of the through-hole 148b in the second locking element 130. This makes it possible to clamp the first locking element 128 and the second locking element 130 against each other by screwing the clamping screw 134 with its external thread 144 into the internal thread 150 of the second locking element 130, thereby shortening the distance between the longitudinal center axes of the first locking element 128 and the second locking element 130.

[0081] Each of the locking elements 128 and 130 comprises a central deflection section 156, which is limited at its end faces (lateral ends) by locking devices 154, which project in the radial direction of the locking element 128 or 130 beyond the deflection section 156.

[0082] The deflection section 156 is designed as a cylinder with radius r, which is flattened on the side facing the clamping plate 108 when the locking system 126 is mounted. The lateral surface 162 of the deflection section 156 thus comprises a cylindrical section-shaped area 158 and a flat area 160.

[0083] How best to get from the Fig. 2 and Fig. As can be seen in Figure 3, the first tension band end 116 of the tension band 114 rests against the first locking element 128 over a portion of the cylindrical section 158 of the outer surface 162 of the deflection section 156 and over the flat area 160 of the outer surface 162 of the deflection section 156 of the first locking element 128. The first tension band end 116 is provided with two through-openings 152a and 152a' through which the tensioning element 130, in the form of the tensioning screw 134, extends when the locking system 126 is assembled.

[0084] In a corresponding manner, the second tension band end 118 lies against the second locking element 130 over a part of the cylindrical section-shaped area 158 of the outer surface 162 of the deflection section 156 of the second locking element 130 and over the flat area 160 of the outer surface 162 of the deflection section 156 of the second locking element 130.

[0085] The second end of the tension band 118 has two passage openings 152b and 152b' through which the shaft area 142 of the tensioning element 132, which is designed as a tensioning screw 134 and is provided with the external thread 144, extends in the assembled state of the locking system 126.

[0086] Furthermore, both locking elements 128 and 130 are each provided with a locking device 154 at their end faces.

[0087] Each of the locking devices 154 can, for example, be designed as a cylindrical disc with radius R, which is flattened on its side facing the clamping plate 108 when the locking system 126 is mounted. The outer surface 164 of the locking device 154 thus comprises a cylindrical section 166 and a flat (planar) section 168, the outer diameter of which exceeds the inner diameter of the tension band loop 120 of the first tension band end 116 or the second tension band end 118, so that the respective tension band end 116, 118 is prevented by the locking devices 154 of the first locking element 128 or the second locking element 138 from sliding down the deflection section 156 of the respective associated locking element 128, 130 in its axial direction.

[0088] The flat area 168 of the outer surfaces 164 of the locking devices 154 of each of the locking elements 128 and 130 runs essentially parallel to the flat area 160 of the outer surface 162 of the deflection section 156 of the same locking element 128 or 130.

[0089] Preferably, the flat areas 168 of the outer surfaces 164 of the locking devices 154 of a locking element 128 or 130 are flush with the flat area 160 of the outer surface 162 of the deflection section 156 of the same locking element 128 or 130, so that the flat areas 168 of the outer surfaces 164 of the locking devices 154 together with the flat area 160 of the outer surface 162 of the deflection section 156 of the respective locking element 128 or 130 form a flat contact surface 170 of the respective locking element 128 or 130 extending continuously from one lateral end of the respective locking element 128 or 130 to the other lateral end of the respective locking element 128 or 130.

[0090] In this case, the locking elements 128 and 130 do not lie directly against the respective adjacent clamping plate 108, but only indirectly via the tensioning band 114, which extends around the deflection section 156 of the respective locking element 128 or 130 and in particular covers the flat area 160 of the outer surface 162 of the deflection section 156.

[0091] Since the flat areas 168 of the outer surfaces 164 of the locking devices 154 of the locking elements 128 and 130 are flush with the flat area 160 of the outer surface 162 of the deflection section 162 of the respective locking element 128 or 130, the locking devices 154 of the locking elements 128 and 130 are spaced apart from the surface of the respective adjacent clamping plate 108 by the material thickness s of the tension band 114 in this embodiment.

[0092] In this way, a direct force transmission from the locking elements 128 and 130 via their locking devices 154 into the adjacent clamping plate 108 is prevented.

[0093] When the stack 102 of electrochemical units 104 of the electrochemical device 100 is clamped, and the clamping screw 134 of the locking system 126 is screwed with its external thread 144 into the internal thread 150 of the second locking element 130, thus tightening the clamping screw 134, only the clamping band 114 slides on the surface of the adjacent clamping plate 108 in the area where it rests against the flat area 168 of the cylindrical surface 160 of a deflection section 156 of one of the locking elements 128, 130. The provision of the flat contact surface 170 on the locking elements 128 and 130 thus prevents the locking elements 128 and 130 from rolling on the surface of the clamping plate 108.

[0094] By preventing the rolling motion, the through holes 148 in the locking elements 128 and 130 are prevented from tilting relative to each other. In contrast to prior art locking systems, with increasing force applied to the locking system 126, the [missing information] in the Fig. In the embodiments shown in Figures 1 to 3, no transverse force component is introduced into the clamping screw 134 of the locking system 126. Due to the elimination of this transverse force component, there is also no increase in the tightening torque required to achieve the predefined clamping force of the stack 102 of electrochemical units 104 of the electrochemical device 100.

[0095] Rather, the tightening torque applied during the assembly process is essentially entirely used to tighten the screw connection of the clamping screw 134. This results in the predefined clamping force being essentially completely transferred to the clamping band ends 116 and 118 and thus to the clamping band 114. Therefore, the predefined clamping force of the stack 102 of electrochemical units 104 is fully achieved, and the electrochemically active areas of the electrochemical units 104 are clamped with sufficient clamping force.

[0096] In this embodiment, the tensioning screw 134 is subjected only to axial and torsion stresses, but not to deflection perpendicular to its longitudinal center axis.

[0097] The tensioning screw 134 can therefore be dimensioned smaller than in the state of the art and thus also requires less installation space.

[0098] One in Fig. Figure 4 shows a partial representation of the second embodiment of an electrochemical device 100, which differs from the one shown in the Fig. 1 to 3 of the first embodiment, in that the deflection sections 156 of the locking elements 128 and 130 of each locking system 126 of a tension band system 112 are completely cylindrical and have no flattening.

[0099] In this embodiment, the lateral surfaces 162 of the deflection sections 156 of the closure elements 128 and 130 therefore comprise only a cylindrical area 172 and no flat area 160.

[0100] In this embodiment, the flat contact surface 170 of each locking element 128 or 130 is therefore formed exclusively by the flat areas 168 of the outer surfaces 164 of the locking devices 154 of the locking elements 128 or 130.

[0101] The distance Δ by which the planar area 168 of the outer surfaces 164 of the locking devices 154 protrudes in the radial direction of the respective locking element 128 or 130 beyond the outer surface 162 of the deflection section 156 is, in this embodiment, preferably equal to or greater than the material thickness s of the tension band 114.

[0102] This ensures that the locking elements 128 and 130, in the assembled state of the locking system 126, are in contact with the flat areas 168 of the outer surfaces 164 of their locking devices 154 on the surface of the respective adjacent clamping plate 108.

[0103] Due to the flatness of these planar areas 168 of the outer surfaces 164 of the locking devices 154, it is also excluded in this embodiment that the locking elements 128 and 130 roll off the clamping plate 108 when the clamping screw 134 of the locking system 126 is tightened.

[0104] Thus, in this embodiment as well, tilting of the through holes 148 in the locking elements 128 and 130 relative to each other is prevented.

[0105] Therefore, this second embodiment achieves the same advantages as the one described in the Fig. 1 to 3 first embodiment shown.

[0106] In principle, the deflection sections 156 of the closure elements 128 and 130 in the second embodiment can have any other cross-section instead of a circular cross-section, for example a polygonal cross-section.

[0107] Furthermore, the statement in the Fig. 4 second embodiment of an electrochemical device 100 with regard to structure, function and method of manufacture with the one described in the Fig. 1 to 3 of the first embodiment shown, to the preceding description of which reference is made.

[0108] One in the Fig. 5 and Fig. Figure 6 shows a partial representation of a third embodiment of an electrochemical device 100, which differs from the one shown in the Fig. 1 to 3 of the first embodiment, in that both the deflection sections 156 and the locking devices 154 of the locking elements 128 and 130 of each locking system 126 of a tension band system 112 are not flattened on one side, but are essentially cylindrical.

[0109] The radius R of each locking device 154 exceeds the radius r of the deflection section 156 of the respective locking element 128 or 130 by a difference Δ, which is smaller than the material thickness s of the tension band 114 guided around the respective deflection section 156 in the area of ​​the respective tension band end 116 or 118.

[0110] This ensures that the tension band end 116 or 118 assigned to a locking element 128 or 130 is guided around the respective locking element 128 or 130 in such a way that the locking element 128 or 130 does not come into contact with the clamping plate 108 adjacent to the locking element 128 or 130 during the tightening of the clamping screw 134.

[0111] Rather, during the clamping of the stack 102 of electrochemical units 104 of the electrochemical device 100, only the respective clamping band end 116 or 118 is in contact with the surface of the adjacent clamping plate 108.

[0112] This ensures that no force can be transmitted from the locking elements 128 and 130 via their locking devices 154 directly into the clamping plate 108.

[0113] During the tightening of the clamping screw 134, only the respective end of the clamping band 116 or 118 slides on the surface of the clamping plate 108, so that the locking devices 154 of the locking elements 128 and 130 do not roll off the clamping plate 108 and thus the through holes 148 in the locking elements 128 and 130 do not tilt relative to each other.

[0114] Therefore, this embodiment also achieves the same advantages as the one described in the Fig. 1 to 3 first embodiment shown.

[0115] In this third embodiment, the diameter of the locking devices 154 is reduced so that it does not exceed the outer diameter of the tension band loop 120 of the first tension band end 116 or of the second tension band end 118.

[0116] The inner diameter of the respective tension band loop 120 is still smaller than the outer diameter of the locking devices 154, so that slippage of the tension band loop 120 in the axial direction of the first locking element 128 or the second locking element 130 from the deflection section 156 of the respective locking element 128 or 130 is prevented.

[0117] Moreover, the one in the Fig. 5 and Fig. 6 third embodiment of an electrochemical device 100 with regard to structure, function and method of manufacture with the one described in the Fig. 1 to 3 of the first embodiment shown, to the preceding description of which reference is made.

[0118] One in Fig. Figure 7 shows a partial illustration of the fourth embodiment of an electrochemical device 100, which differs from the one shown in the Fig. 1 to 3 of the first embodiment, in that the clamping screw 134 of each locking system 126 does not engage in an internal thread 150 of one of the locking elements 128, 130 of the locking system 126, but instead engages with a clamping nut 174, which is arranged on the end region of the shaft of the clamping screw 134 facing away from the screw head 136.

[0119] The clamping nut 174 has an internal thread 176 which is complementary to the external thread 144 of the clamping screw 134.

[0120] The clamping nut 174 can comprise an actuation area 178, on which, for example, a wrench or other actuation tool can engage, and a sleeve area 180, which has a smaller outer diameter than the actuation area 178.

[0121] In the assembled state of the locking system 126, the clamping nut 174 is arranged on one side of one of the locking elements 130 of the locking system 126 facing away from the other locking element 128 and presses this locking element 130 towards the other locking element 128.

[0122] The locking screw 134 is guided in the two through holes 148a, 148b of the first locking element 128 and the second locking element 130 respectively with such a large clearance that the external thread 144 of the clamping screw 134 does not come into contact with the first locking element 128 or with the second locking element 130.

[0123] In this embodiment, the locking devices 154 of the locking elements 128 and 130 are indeed in contact with the respective adjacent clamping plate 108 during the clamping of the stack 102 of electrochemical units 104 of the electrochemical device 100, so that when the clamping element 132 is tightened, the locking elements 128 and 130 can roll off the clamping plate 108. Preferably, however, the clearance of the clamping screw 134 in the through holes 148a, 148b is so large that even if the through holes 148a and 148b tilt relative to each other, no transverse force component is applied to the clamping screw 134.

[0124] Furthermore, the tightening of the screw connection of the locking system 126 can be achieved by rotating the clamping nut 174 about the longitudinal axis of the clamping screw 134. This makes the tightening torque between the clamping nut 174 and the clamping screw 134 independent of any possible deflection of the clamping screw 134 in the area between the locking elements 128 and 130 due to a possible shear force component introduced into the clamping screw 134.

[0125] Even with a relatively strong deflection of the clamping screw 134, it is thus ensured that the full tightening torque acts between the first clamping band end 160 and the second clamping band end 118, so that the predefined clamping force of the stack 102 of electrochemical units 104 is fully achieved and sufficient compression of the electrochemically active areas of the electrochemical units 104 of the electrochemical device 100 is achieved.

[0126] At the in Fig. In the fourth embodiment shown in Figure 7, the friction between the clamping screw 134 and the internal thread of the second locking element 130 is thus reduced by the fact that the external thread 144 of the clamping screw 134 does not engage in an internal thread of the second locking element 130 at all, but exclusively in the internal thread 176 of the clamping nut 174.

[0127] Moreover, the in Fig. 7 fourth embodiment of an electrochemical device 100 with regard to structure, function and method of manufacture with the one described in the Fig. 1 to 3 of the first embodiment shown, to the preceding description of which reference is made.

[0128] One in Fig. Figure 8 shows a partial illustration of the fifth embodiment of an electrochemical device 100, which differs from the one shown in the Fig. 1 to 3 of the first embodiment, in that the through-hole 148a in the first closure element 128, on which the screw head 136 of the clamping screw 134 rests, has been enlarged in diameter so that the clamping screw 134 is guided in this through-hole 148a with so much play that the shaft of the clamping screw 134 does not come into contact with the boundary wall of this through-hole 148a when the clamping screw 134 is tightened during the clamping of the stack 102 of electrochemical units 104 of the electrochemical device 100.

[0129] This prevents a transverse force from being exerted on the clamping screw 134 by the first clamping element 128 when the locking elements 128 and 130 roll down the surface of the adjacent clamping plate 108 during the tightening of the clamping screw 134.

[0130] This also reduces the friction between the external thread 144 of the clamping screw 134 and the internal thread 150 of the through hole 148b in the second locking element 130.

[0131] In this way, the occurrence of a transverse force component leading to a deflection of the clamping screw 134 when tightening the clamping screw 134 cannot be completely avoided, but it can at least be reduced, so that a reduction of the tightening torque of the locking system 126 applied in the assembly process of the electrochemical device 100 is at least reduced.

[0132] Preferably, the diameter of the through hole 148a in the first closure element 128 exceeds the outer diameter of the external thread 144 of the clamping screw 134 by at least 5%, particularly preferably by at least 10%.

[0133] Moreover, the in Fig. Figure 8 shows the fifth embodiment of an electrochemical device 100 with regard to its structure, function and method of manufacture, compared to the one described in the Fig. 1 to 3 of the first embodiment shown, to the preceding description of which reference is made.

Claims

[1] Clamping device for clamping a stack (102) of electrochemical units (104) which follow one another along a stacking direction (106) and are arranged between clamping plates (108), wherein the clamping device (110) comprises at least one clamping band system (112), wherein each tension band system (112) comprises at least one tension band (114) which has a first tension band end (116) and a second tension band end (118), and comprising at least one locking system (126) for connecting a first tension band end (116) of a tension band (114) to a second tension band end (118) of the same tension band (114) or of another tension band (114), wherein the locking system (126) comprises a first locking element (128) which is in contact with a first tension band end (116), a second locking element (130) which is in contact with a second tension band end (118), and a clamping element (132) for clamping the first locking element (128) and the second locking element (130) comprises, characterized by , that the first locking element (128) and / or the second locking element (130) has a substantially flat contact surface (170) with which the respective locking element (128, 130) bears against a section of the tensioning band (114) guided around the respective locking element (128, 130) and / or against one of the clamping plates (108) during the tightening of the clamping element (132). [2] Clamping device according to claim 1, characterized by , that the planar mounting surface (170) extends from a first lateral end of the relevant closure element (128, 130) to a second lateral end of the relevant closure element (128, 130). [3] Clamping device according to one of claims 1 or 2, characterized by, that the first locking element (128) and / or the second locking element (130) each comprise at least one locking device (154) which has a cylindrical surface (164) which includes a flat area (168), wherein the locking element (128, 130) in question bears against one of the clamping plates (108) with the flat area (168) of the cylindrical surface (164) of the at least one locking device (154) during the tightening of the clamping element (132). [4] Clamping device according to the preamble of claim 1, characterized by , that at least one end of the tension band (116, 118) is guided around one of the locking elements (128, 130) in such a way that the locking element (128, 130) in question is not in contact with a clamping plate (108) adjacent to the locking element (128, 130) during the tightening of the tensioning element (132). [5] Clamping device according to claim 4, characterized by, that at least one of the locking elements (128, 130) comprises a deflection section (156) around which the tension band end (116, 118) assigned to the locking element (128, 130) is guided, and comprises at least one loss-proof device (154), wherein a radius (R) of the loss-proof device (154) exceeds a radius (r) of the deflection section (156) by a difference (Δ) which is smaller than a material thickness (s) of the tension band (114) in the area of ​​the tension band end (116, 118) in question. [6] Clamping device according to claim 5, characterized by , that the deflection section (156) is essentially cylindrical. [7] Clamping device according to one of claims 5 or 6, characterized by , that the first locking element (128) and / or the second locking element (130) comprises two locking devices (154) which are spaced apart from each other by the deflection section (156) of the respective locking element (128, 130). [8] Clamping device according to the preamble of claim 1, characterized by , that the clamping element (132) comprises at least one locking system (126) and at least one tensioning band system (112), a clamping screw (134) and a clamping nut (174) arranged on the clamping screw (134). [9] Clamping device according to the preamble of claim 1, characterized by , that the clamping element (132) of at least one closure system (126) of at least one tension band system (112) is passed through a through hole (148a) in the first closure element (128), wherein the smallest diameter of the through hole (148a) exceeds the largest outer diameter of the clamping element (182) in the area of ​​the through hole (148a) by at least 5%. [10] Clamping device according to the preamble of claim 1, characterized by, that the clamping element (132) of at least one closure system (126) of at least one tension band system (112) is passed through a through hole (148b) in the second closure element (130), wherein the smallest diameter of the through hole (148b) exceeds the largest outer diameter of the clamping element (132) in the area of ​​the through hole (148b) by at least 5%. [11] Clamping device according to any one of claims 1 to 10, characterized by , that the clamping element (132) of at least one locking system (126) of at least one tension band system (112) comprises a clamping screw (134) which engages in an internal thread (150) which is arranged on one of the locking elements (128, 130). [12] Clamping device according to any one of claims 1 to 11, characterized by, that at least one of the tension band ends (116, 118) forms a tension band loop (120) in which the tension band (114) is guided back on itself and is fixed to a fixing section (124) of the tension band (114). [13] Clamping device according to any one of claims 1 to 12, characterized by , that at least one of the tension band ends (116, 118) has at least one passage opening (152) through which the tensioning element (132) passes. [14] Clamping device according to claim 13, characterized by, that at least one clamping element (132) of at least one locking system (126) of at least one tensioning band system (112) comprises a clamping screw (134) which has an actuating area (138) and / or a clamping nut (174) which has an actuating area (178), wherein the passage opening (152) through which the clamping element (132) passes in the clamped state of the clamping device (110) is arranged between the actuating area (138; 178) of the clamping screw (134) or the clamping nut (174) on the one hand and the locking element (128; 130) of the locking system (126) which is closest to the actuating area (138; 178) on the other hand. [15] Method for clamping a stack (102) of electrochemical units (104) arranged along a stacking direction (106) and between clamping plates (108) by means of a clamping device (110), wherein the clamping device (110) comprises at least one clamping band system (112), wherein each tension band system (112) comprises at least one tension band (114) which has a first tension band end (116) and a second tension band end (118), and comprising at least one locking system (126) for connecting a first tension band end (116) of a tension band (114) to a second tension band end (118) of the same tension band (114) or of another tension band (114), wherein the locking system (126) comprises a first locking element (128) which is in contact with a first tension band end (116), a second locking element (130) which is in contact with a second tension band end (118), and a clamping element (132) for clamping the first locking element (128) and the second locking element (130) comprises, characterized by , that the locking elements (128, 130), the tension band ends (116, 118) and the tensioning element (132) are designed such that when the tensioning element (132) is tightened, essentially no transverse force component oriented perpendicular to a longitudinal direction of the tensioning element (132) acts from the locking elements (128, 130) onto the tensioning element (132).

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