Fuel cell stack assembly with compression device

Abstract

There is provided a cell stack assembly (100) comprising at least: an electrical energy generating cell stack body (102) having a plurality of unit cells stacked in a stacking direction (104): first and second end plates (106) sandwiching the cell stack body (102), where at least one end plate (106) has an opening (108, 114) in a side surface (110); and at least one compression element (1) configured to compress the cell stack (102) between the first and second end plates (106) in the stacking direction (104) wherein the at least one compression element (1) comprises a belt element (2) having a first attachment element (8) arranged at a first end (4) and a second attachment element (10) arranged at a second end (6), wherein the first attachment element (8) is an anchor bolt-like element (12) protruding from the compression element (1) perpendicular to the stacking direction (104), and the second attachment element (10) is an anchor bolt-like element (8) protruding from the compression element perpendicular to the stacking direction (104) or a pressure adjustment element (24) configured to adjust a pressure exerted by the at least one compression element (1) in the stacking direction (104), wherein each anchor bolt-like element (12) is integrally formed with the belt element (2) or is permanently fixed to the belt element (2), and wherein at least one anchor bolt-like element (12) is inserted into an opening (108) provided in a side face (110) of at least one end plate (106).

Description

Technical Field

[0001] The invention relates to a battery stack assembly. Background Art

[0002] Typically, a cell stack assembly such as a fuel cell stack comprises a stack body comprising a plurality of unit cells stacked in a stacking direction. Each unit cell comprises at least two plates, so-called flow field plates, which are arranged on top of each other and have a flow field for reactants on one side and a flow field for a cooling fluid on the other side. Thus, the flow fields of adjacent plates form channels through which the corresponding fluids flow.

[0003] In order to avoid any fluid leakage and achieve fluid sealing of the battery stack, the stack body is compressed in the stacking direction by means of a compression element. For example, document KR101466507A1 describes a stack assembly in which the stack body is clamped between two end plates. Each end plate includes an insertion groove and a fixing plate, the insertion groove having a recess on the side surface of the end plate, and the fixing plate extends from the bottom surface of the insertion groove parallel to the outer peripheral surface of the end plate and extends into the insertion groove. The compression of the stack assembly is achieved by inserting the two ends of the fastening band between the insertion groove of the end plate and the fixing plate, and the fastening band extends along the side surface of the stack body, wherein each end of the fastening band is T-shaped. However, in order to insert the fastening band between the insertion groove and the fixing plate of the end plate, the required stack compression exceeds the compression of the completed stack assembly. In other words, the stack body must be subjected to greater compression during the stacking process of the battery stack than during normal operation. Therefore, during the installation of the fastening band, there is a risk that components of the battery stack assembly are damaged. Summary of the invention

[0004] It is therefore an object of the present invention to provide a battery stack assembly having an improved compression element for a battery stack assembly which reduces the risk of damaging the battery stack assembly during installation of the compression element.

[0005] This object is solved by a cell stack assembly according to claim 1 .

[0006] In the following, a battery stack assembly, in particular a fuel cell stack assembly, is provided, comprising at least one electric energy generating battery stack body, the electric energy generating battery stack body having a plurality of unit cells stacked in a stacking direction, wherein each unit cell is preferably a unit fuel cell including a bipolar plate and a membrane electrode assembly. The stack assembly also comprises first and second end plates and at least one compression element, the first and second end plates sandwiching the electric energy generating battery stack body, wherein at least one end plate has an opening in a side surface, and the compression element is configured to compress the battery stack body between the first and second end plates in the stacking direction.

[0007] At least one compression element comprises a band element having a first end and a second end, wherein at least one compression element comprises a first attachment element arranged at the first end and a second attachment element arranged at the second end. The first attachment element is an anchor bolt-shaped element protruding from the compression element perpendicular to the stacking direction, and the second attachment element is an anchor bolt-shaped element protruding from the compression element perpendicular to the stacking direction or a pressure adjustment element configured to adjust the pressure applied by at least one compression element in the stacking direction, wherein each anchor bolt-shaped element is integrally formed with the band element or permanently fixed to the band element, wherein at least one anchor bolt-shaped element is inserted into an opening provided in the side of at least one end plate. This configuration has the advantage that excessive compression of the stack assembly can be avoided during assembly. More specifically, during assembly, the stack is compressed to the height of the completed stack assembly at most, so that the attachment element can be inserted into the corresponding opening in the end plate. Therefore, the risk of damaging the stack body components is reduced. In addition, since at least one anchor bolt-shaped element is permanently fixed to the band element or integrally formed with the band element, the height of the stack assembly can be maintained during the life of the stack assembly.

[0008] Preferably, the strap element has a predetermined length. Preferably, the length is adapted to provide a desired pressure of the stack assembly under operating conditions. This enables the pressure to be determined in the case where the first and second attachment elements are configured as anchor bolt-like elements, without the risk of over-compressing the stack assembly. For example, at least one compression element may be made of sheet metal. Preferably, the anchor bolt-like elements may be welded, glued and / or riveted to the strap element.

[0009] According to another embodiment, the anchor bolt-shaped element and / or the pressure regulating element has a bolt-shaped element, wherein the bolt-shaped element has a circular, rectangular, elliptical, triangular or polygonal cross section and / or has a square, cone, truncated cone or pyramid shape and / or has at least one chamfered edge. Preferably, the opening formed in at least one end plate has a shape complementary to the bolt-shaped element. This has the advantage that the position of the bolt-shaped element can be defined within the opening. In addition, the contact area between the opening and the bolt-shaped element can be increased, which increases the friction between the opening and the bolt-shaped element, so that the position of the bolt-shaped element in the opening is fixed.

[0010] Furthermore, the anchor bolt-like element comprises at least one position fixing element configured to fix the position of the anchor bolt-like element. This reduces the risk of the anchor bolt-like element being detached from the end plate due to vibrations and / or other external forces.

[0011] Preferably, the anchor bolt-like element comprises a through hole, wherein the longitudinal axis of the through hole is perpendicular to the stacking direction, wherein the through hole is suitable for accommodating the position fixing element and / or interacting with the position fixing element. This enables the position fixing element to be inserted through the through hole. For example, the position fixing element can be permanently fixed in an opening of the end plate, and the anchor bolt-like element can be assembled to the position fixing element and fixed in position by suitable means such as nuts, glue and / or welding. Optionally, the position fixing element can be inserted and fixed in the end plate through the through hole in the anchor bolt-like element.

[0012] According to another embodiment, the pressure regulating element comprises a tensioning element, which is suitable for applying tension in a direction parallel to the stacking direction. Preferably, the tensioning element is also configured to continuously adjust the pressure applied in the stacking direction. Thus, the tensioning element is able to continuously increase and / or reduce the pressure applied to the battery stack assembly. In addition, the pressure regulating element may include a through hole, wherein the longitudinal axis of the through hole is parallel to the stacking direction, wherein the through hole is suitable for accommodating the tensioning element and / or interacting with the tensioning element.

[0013] Preferably, the position fixing element and / or the tensioning element is a bolt or a screw.

[0014] According to another embodiment, the pressure regulating element comprises a ring, which is formed at the second end of the band element by folding the band element back onto itself and fastening the folded end to the band element, wherein a bolt-shaped element with a through hole is fixed in the ring. For example, the folded end of the band element can be welded, screwed, bolted, riveted and / or glued to the remaining band element. The bolt-shaped element can be arranged in the ring and fixed to the band element. Furthermore, the band element can be provided with an opening such as a slot or an elongated hole, so that the bolt-shaped element is at least partially accessible after the bolt-shaped element is fixed in the ring of the band element. For example, the bolt-shaped element can be welded, screwed, bolted, riveted and / or glued to the ring.

[0015] Further preferred embodiments are defined in the dependent claims as well as in the description and drawings. Hence, elements described or shown in combination with other elements may exist alone or in combination with other elements without departing from the scope of protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In the following, preferred embodiments of the present invention are described in conjunction with the accompanying drawings, wherein the accompanying drawings are only exemplary and are not intended to limit the scope of protection. The scope of protection is limited only by the attached claims.

[0017] The accompanying drawings show:

[0018] Figure 1 shows a perspective view of a compression element according to a first embodiment,

[0019] Figure 2 Shows that there is Figure 1 An exploded side view of the battery stack assembly showing the compression element,

[0020] Figure 3 shows a perspective view of a compression element according to a second embodiment, and

[0021] Figure 4 Shows that there is Figure 3 An exploded side view of the cell stack assembly showing the compression elements. DETAILED DESCRIPTION

[0022] In the following, identical or similar functional elements are denoted by the same reference numerals.

[0023] Figure 1 A compression element 1 according to a first embodiment is shown. The compression element 1 has a band-like element 2 having a first end 4 and a second end 6. A first attachment element 8 and a second attachment element 10 are arranged at the first end 4 and the second end 6, respectively. Figure 1 In the embodiment, both attachment elements 8, 10 are anchor bolt-like elements 12 protruding from the compression element 1 perpendicularly to the longitudinal direction of the band element 2. Figure 2 As can be seen in FIG. 1 , the longitudinal direction of the band element 2 is parallel to the stacking direction 104 of the battery stack assembly 100 , so that when arranged at the battery stack assembly 100 , the anchor bolt-like elements 8 , 10 protrude perpendicularly to the stacking direction 104 from the compression element 1 .

[0024] The band element 2 has a predetermined length and is made of a metal sheet. Each anchor bolt-shaped element 12 is permanently fixed to the band element by welding, and each anchor bolt-shaped element 12 is configured to be inserted into an opening ( Figure 2 However, the anchoring bolt-like element 12 can also be glued and / or riveted to the belt element 2 or can even be formed integrally with the belt element 2, for example by a casting process.

[0025] The anchor bolt-shaped element 12 comprises a bolt-shaped element 14 having a cylindrical shape with a chamfered top edge 16. Alternatively, the bolt-shaped element 14 may have any other suitable shape that can be inserted into the opening. For example, the bolt-shaped element 14 may have a circular, rectangular, elliptical, triangular or polygonal cross section and / or may have a square, cone, truncated cone or pyramid shape.

[0026] Figure 2 1 shows an exploded side view of a battery stack assembly 100. The battery stack assembly 100 may be a fuel cell stack assembly. Figure 2As shown, the battery stack assembly 100 includes an electric energy generating battery stack 102, and the battery stack 102 has a plurality of unit cells stacked in a stacking direction 104. The stack assembly 102 also includes first and second end plates 106 sandwiching the electric energy generating battery stack 102. The electric energy generating battery stack 102 is sandwiched between two terminal plates 118, and the terminal plates 118 are insulated from the end plates 106 by two insulating plates 120.

[0027] exist Figure 2 In the embodiment of the present invention, the two end plates 106 have an opening 108 in each side 110, the side 110 having a normal vector perpendicular to the stacking direction 104. The opening 108 has a shape complementary to the bolt-like element 14. This configuration has the advantage that the attachment elements 8, 10 increase the contact area between the bolt-like element 14 and the opening 108.

[0028] When assembling the stack assembly 100, the stack is compressed to a predetermined height and then the bolt-like elements 14 of the attachment elements 8, 10 are inserted into the corresponding openings 108 in the end plates 106. In order to account for any deviations in the dimensions of the components of the stack assembly 100, such as tolerances caused by manufacturing, the stack assembly 100 also includes two spring elements 122 and a compression plate 124. The compression plate 124 is arranged between the upper insulating plate 114 and the upper end plate 106, wherein the spring elements are arranged between the compression plate 124 and the end plate 106. Because each anchor bolt-like element 12 is permanently fixed to the band element 2 by welding, the position of the attachment elements 8, 10 is fixed, so that the compression amount and height of the stack are maintained during the life of the stack assembly 100.

[0029] In order to fix the position of the attachment elements 8, 10, the two anchor bolt-like elements 12 each include a through hole 18, through which a screw 20 is inserted, and the screw 20 is screwed into a thread 112 provided in the opening 108 of the end plate 106. Therefore, the through hole 18, the screw 20 and the thread 112 form a position fixing element configured to fix the position of the attachment elements 8, 10. Alternatively, the position fixing element may be a bolt permanently fixed in the opening 108 of the end plate 106, and the anchor bolt-like element 12 may be assembled to the position fixing element and fixed in position by suitable means such as nuts, glue and / or welding.

[0030] Figure 3 A compression element 1 according to a second embodiment is shown. The compression element has a band-like element 2 having a first end 4 and a second end 6. A first attachment element 8 and a second attachment element 10 are arranged at the first end and at the second end, respectively. Figure 3 In the embodiment, the first attachment element 8 is an anchor bolt-like element 12 as described above. The second attachment element 10 is configured to adjust the pressure ( Figure 4)'s pressure regulating element 24.

[0031] The pressure regulating element 24 has a cylindrical bolt-shaped element 26. Alternatively, the bolt-shaped element 26 can have any other suitable shape. For example, the bolt-shaped element 26 can have a circular, rectangular, elliptical, triangular or polygonal cross section and / or can have a square, cone, truncated cone or pyramid shape and / or have at least one chamfered edge. In addition, the pressure regulating element 24 includes a ring 28, which is formed at the second end 6 of the compression element 1 in the following manner, folding the band element 2 back onto itself and fastening the folded end to the band element 2. For example, the folded end can be welded, screwed, bolted, riveted and / or glued. The bolt-shaped element 26 is arranged in the ring 28 and fixed to the band element 2 by welding. In this case, the band element 2 is provided with an elongated hole 30 so that the bolt-shaped element 26 is at least partially accessible after the bolt-shaped element 28 is welded to the band element 2.

[0032] Figure 4 1 shows an exploded side view of a battery stack assembly 100. The battery stack assembly 100 may be a fuel cell stack assembly. Figure 4 As shown, the battery stack assembly 100 includes an electric energy generating battery stack 102, and the battery stack 102 has a plurality of unit cells stacked in a stacking direction 104. The stack assembly 102 also includes a first and a second end plate 106, and the first and the second end plates 106 sandwich the electric energy generating battery stack 102. The electric energy generating battery stack 102 is sandwiched between two terminal plates 118, and the terminal plates 118 are insulated from the end plates 106 by two insulating plates 120. In order to solve any deviations in the dimensions of the components of the stack assembly 100, such as tolerances caused by manufacturing, the stack assembly 100 also includes two spring elements 122 and a compression plate 124. The compression plate 124 is arranged between the upper insulating plate 114 and the upper end plate 106, wherein the spring element is arranged between the compression plate 124 and the end plate 106.

[0033] like Figure 4 As shown, one of the end plates 106 has an opening 108 as described above, which has a shape complementary to the bolt-like element 14 of the first attachment element 8. The other end plate 106 has an opening 114, which is suitable for receiving the pressure adjustment element 24 of the second attachment element 10. In addition, the other end plate 106 includes a through hole 116, through which a tensioning element 32 such as a screw or bolt can be inserted, and the through hole 116 is configured to cooperate with the hole 34 in the bolt-like element 26.

[0034] When assembling the stack assembly 100, the first attachment element 8 with the anchor bolt-like element 12 is inserted into the corresponding opening 108. The other end can then be aligned with the opening 114 in the other end plate 106, and the tensioning element 32 can then be tightened with an appropriate torque so that the pressure applied to the stack 100 is adjustable while the stack 100 still maintains a certain rigidity.

[0035] The tensioning element 32 is adapted to apply tension in a direction parallel to the stacking direction 104. By tightening and / or loosening the tensioning element 32, the pressure applied by the compression element 1 in the stacking direction 104 can be continuously adjusted. Therefore, the tensioning element 32 is capable of continuously increasing and / or decreasing the pressure applied to the battery stack assembly 100. The hole 34 can be configured as a through hole, wherein the longitudinal axis of the through hole is parallel to the stacking direction 104.

[0036] In summary, the described compression elements provide a compressive holding force that can be maintained throughout the life of the battery stack assembly. More specifically, embodiments having two anchor bolt-like elements can provide as much rigidity as a screw while using significantly less space and weight. In addition, since the length is completely predetermined, the risk of tilting, force imbalance and / or other assembly-related problems is eliminated or at least reduced. In addition, embodiments having a pressure adjustment element provide sufficient rigidity while still being adjustable to accommodate changes in battery stack height.

[0037] An advantage of both described embodiments is that the compression elements are arranged only on the sides of the cell stack assembly, so that the surfaces on the top and bottom of the cell stack assembly are free and can be used for other functions.

[0038] Reference numerals

[0039] 1 Compression element

[0040] 2 With components

[0041] 4 First End

[0042] 6 Second End

[0043] 8 First attachment element

[0044] 10 Second attachment element

[0045] 12 Anchor bolt-like elements

[0046] 14 Bolt-like elements

[0047] 16 Top edge

[0048] 18 through holes

[0049] 20 position fixed element

[0050] 24 Pressure regulating element

[0051] 26 bolt-like elements

[0052] 28 rings

[0053] 30 Slim hole

[0054] 32 tensioning elements

[0055] 34 through holes

[0056] 100 Battery stack components

[0057] 102 Electricity generating battery stack

[0058] 104 Stacking direction

[0059] 106 End Plate

[0060] 108 Opening

[0061] 110 Side

[0062] 112 Thread

[0063] 114 Opening

[0064] 116 Through Hole

[0065] 118 Terminal board

[0066] 120 Insulation board

[0067] 122 Spring element

[0068] 124 Compression Plate

Claims

1. A battery stack assembly (100), in particular a fuel cell stack assembly, comprising at least: An electric energy generating cell stack (102) having a plurality of unit cells stacked in a stacking direction (104), wherein each unit cell is preferably a unit fuel cell including a bipolar plate and a membrane electrode assembly, First and second end plates (106) sandwiching the power generating cell stack (102), wherein at least one of the end plates (106) has an opening (108, 114) in a side (110), and at least one compression element (1) configured to compress the electrical energy generating cell stack (102) between the first and second end plates (106) in the stacking direction (104), Features The at least one compression element (1) comprises a strip-like element (2) having a first end and a second end (4, 6), wherein the at least one compression element (1) comprises a first attachment element (8) arranged at the first end (4) and a second attachment element (10) arranged at the second end (6), wherein the first attachment element (8) is an anchor bolt-like element (12) protruding from the compression element (1) perpendicular to the stacking direction (104), and the second attachment element (10) is an anchor bolt-like element (12) protruding perpendicular to the stacking direction (104). An anchor bolt-like element (8) protruding from the compression element in the stacking direction (104) or a pressure adjustment element (24) configured to adjust the pressure applied by the at least one compression element (1) in the stacking direction (104), wherein each anchor bolt-like element (12) is formed integrally with the belt element (2) or is permanently fixed to the belt element (2), wherein at least one anchor bolt-like element (12) is inserted into an opening (108) provided in a side surface (110) of the at least one end plate (106).

2. The battery stack assembly (100) according to claim 1, wherein the strip-shaped element (2) has a predetermined length.

3. A battery stack assembly (100) according to claim 1 or 2, wherein the anchoring bolt-shaped element (12) and / or the pressure adjusting element (24) has a bolt-shaped element (14, 26), wherein the bolt-shaped element (14, 26) has a circular, rectangular, elliptical, triangular or polygonal cross-section, and / or has a square, cone, truncated cone or pyramid shape, and / or has at least one chamfered edge.

4. The battery stack assembly (100) according to claim 3, wherein the opening (108, 114) formed in the at least one end plate (106) has a shape complementary to the bolt-like element (14, 26).

5. A battery stack assembly (100) according to any one of the preceding claims, wherein the anchor bolt-like element (12) includes at least one position fixing element (20), which is configured to fix the position of the attachment element (8, 10) in the opening (108, 114).

6. A battery stack assembly (100) according to claim 5, wherein the anchoring bolt-like element (12) includes a through hole (18), wherein the longitudinal axis of the through hole (18) is perpendicular to the stacking direction (104), and wherein the through hole (18) is suitable for accommodating the position fixing element (20) and / or interacting with the position fixing element (20).

7. The battery stack assembly (100) according to any of the preceding claims, wherein the pressure regulating element (24) comprises a tensioning element (32), the tensioning element (32) being suitable for applying a tensile force in a direction parallel to the stacking direction (104).

8. The battery stack assembly (100) according to claim 7, wherein the pressure regulating element (24) includes a through hole (34), wherein the longitudinal axis of the through hole (34) is parallel to the stacking direction (104), and wherein the through hole (34) is suitable for accommodating the tensioning element (32) and / or interacting with the tensioning element (32).

9. A battery stack assembly (100) according to claim 8, wherein the pressure regulating element (24) includes a ring (28), which is formed at the second end (6) of the belt element (2) by folding the belt element (2) backward onto the belt element (2) itself and fastening the folded end to the belt element (2), wherein the bolt-like element (24, 26) having the through hole (34) is fixed in the ring (28).

10. The battery stack assembly (100) according to claims 5 to 9, wherein the position fixing element (20) and / or the tensioning element (32) is a bolt or a screw.

11. The cell stack assembly (100) according to any one of the preceding claims, wherein the at least one compression element (1) is made of a metal sheet.

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