Electrochemical cell with overhang

Abstract

The present invention relates to an electrochemical cell assembly (10) comprising a housing (32) and an end plate (14), wherein the housing (32) has a protruding upright section (48) extending beyond the end plate (14).

Description

Technical Field

[0001] This invention relates to the field of electrochemical battery stacks, and more particularly to fuel cell stacks and electrolyzer battery stacks. More specifically, this invention relates to an electrochemical battery assembly. Background Technology

[0002] Fuel cells and electrolyzers are both examples of electrochemical cells. A fuel cell is a type of energy conversion device that converts electrochemical fuel into electrical energy. An electrolyzer is a fuel cell that operates in reverse mode, using electrical energy to break down a compound into its constituent parts, such as water (H2O) into hydrogen and oxygen. Reversible cells can operate in both modes. These types of electrochemical cells typically include electrochemical active layers that can be configured to either convert electrochemical fuel into electrical energy (fuel cell) or use electrical energy to break down a compound into its constituent parts (electrolyzer).

[0003] This invention particularly relates to solid oxide batteries (SOCs). Such solid oxide batteries (SOCs) typically include an electrolyte layer formed of solid oxides, such as yttrium-stabilized zirconium oxide (YSZ), cerium oxide doped with gadolinium oxide, or cerium-gadolinium oxide (CGO). SOCs can operate as solid oxide fuel cells (SOFCs) or as solid oxide electrolyzers (SOECs).

[0004] Typically, multiple such battery cells are stacked together to form a "stack" of battery cells, also known as a "repeating battery cell." This stack is usually arranged between two end plates on opposite sides of the stack, thus forming an electrochemical battery assembly. The end plates typically serve as inlets for supplying fluid, particularly fuel, to the battery stack. For this purpose, at least one of the two end plates may include at least one through-hole formed in the at least one end plate to form a fluid port for supplying fluid from outside the electrochemical battery assembly to the battery cell stack. An electrical contact may be provided on the other end plate. In this invention, the fluid port and electrical contact may also be arranged in other ways.

[0005] In the assembled state, the stack is typically held in a compressed state between the endplate assemblies to ensure tight and uniform contact between the individual cell units. For this purpose, prior art electrochemical cell assemblies include additional compression devices such as levers, compression springs, or bolts. Compression is also known to be provided via a housing. The housing surrounds the stack and extends around the outer periphery of the cell units to enclose the stack cavity. The housing is secured to the endplates, and the cell stack between the endplates is compressed, with the endplates fixed in an opposing position to each other by attachment to the housing.

[0006] The attachment between the housing and the end plate can be achieved in different ways, such as welding. Summary of the Invention

[0007] The purpose of this invention is to provide an electrochemical battery assembly or stack that achieves flexibility in the connection between the housing and the end plate and can compensate for manufacturing tolerances.

[0008] According to the present invention, an electrochemical battery assembly is provided, comprising: a first end plate assembly having a first end plate, a second end plate assembly having a second end plate, and a stack of battery cells, the stack comprising a plurality of battery cells stacked together along a stacking direction, each of the plurality of battery cells defining an outer perimeter in a plane extending perpendicular to the stacking direction.

[0009] The battery cell stack is arranged between the first end plate and the second end plate along the stacking direction, preferably held in a compressed state between the first end plate and the second end plate. The first end plate and the second end plate are preferably located on opposite sides of the battery cell stack, such that when viewed along the stacking direction, one of the two end plates is located in front of the battery cell stack, while the other end plate is located behind the battery cell stack.

[0010] The electrochemical battery assembly also includes a housing that surrounds the stack and extends around the outer periphery of the battery cell to enclose a cavity within the stack. The battery cell is sealed by the housing to prevent fuel leakage from the cavity. The housing is connected to a first end plate and a second end plate located on opposite sides of the stack of battery cells.

[0011] The housing is connected to at least one of the two end plates, namely the first end plate and / or the second end plate, by a weld seam extending along the outer perimeter of the connected end plates. This weld seam is specifically formed using cold metal transfer welding. In particular, if the housing and end plate fail to make complete contact along the entire outer perimeter of the end plate, cold metal transfer welding can produce spatter particles that may enter the enclosed stack cavity. Similar problems arise when other welding methods are used to connect the housing and end plates.

[0012] To enhance the flexibility of electrochemical battery assembly assembly, the housing extends along the stacking direction beyond at least one of the connected first and / or second end plates, such that the housing includes a protruding upright section. This protruding upright section allows the housing and end plates to be connected at locations defined by the end plate positions (along the stacking direction) and at variable positions on the housing. For example, this structure can accommodate variations in the thickness of the battery stack. The battery stack can be compressed to the desired degree between the end plates, and the end plates can be connected to the housing at appropriate locations on one side of the protruding upright section to maintain this compression. The length of the housing along the stacking direction does not limit the position of the end plates, as the end plates can "move" along the housing, thereby lengthening or shortening the protruding upright section of the housing. This not only accommodates variations in battery stack height due to manufacturing tolerances but also allows the use of the same type of housing to manufacture different types of electrochemical battery assemblies with different battery stacks and varying numbers of cells.

[0013] On the side of the battery cell stack with the protruding upright section, the housing is connected to the corresponding end plate by a weld. This weld can extend along the outer periphery of the end plate. The weld can be surrounded and connected to the housing. Specifically, the weld can be connected to the protruding upright section of the housing. This weld is located inside the housing, allowing for a suitable position to be selected along the extension of the housing in the stacking direction.

[0014] On one side of the battery cell stack with a protruding upright section, the housing can be connected to the corresponding end plate via a weld. The weld can extend along the outer perimeter of the end plate and can be located at the corner formed between the protruding upright section of the housing and the end plate. This is an easily accessible location, and the weld can be easily formed here.

[0015] On the side of the battery cell stack with the protruding upright section, the casing and the corresponding end plate can be connected by a weld formed by cold metal transfer welding. The other end plate can also be connected in the same way. Cold metal transfer welding is an excellent connection method suitable for mass production processes.

[0016] The housing includes at least two skirt-shaped segments extending along the stacking direction. Specifically, the housing may consist essentially of two skirt-shaped segments. The skirt-shaped segments may be arranged around the stack during assembly and then connected to end plates to ensure the sealing and compression of the stack.

[0017] Specifically, the shell includes at least one skirt-like segment, particularly two skirt-like segments, which have a U-shaped cross-section when viewed along the stacking direction. Such skirt-like segments can be conveniently placed around the stack in a brace-like manner. These two U-shaped skirt-like segments can be placed around the stack from opposite sides and then connected to each other. The "U-shape" here includes two straight legs extending toward the opening side, and a connecting segment located on the opposite side of the opening side. For example, the connecting segment can be curved, straight, or composed of multiple interconnected straight segments. In particular, one of the multiple straight segments can be positioned perpendicular to the legs and, in particular, can connect to another straight segment that extends at an angle from the perpendicular segment toward the legs. Specifically, the leg length of the U-shaped segment can be greater than the distance between the two legs.

[0018] The protruding upright section of the housing can extend beyond the corresponding end plate (the end plate located on one side of the protruding upright section) by a distance greater than the thickness of the end plate. This ensures that sufficient space is left to form a weld for connecting the housing and the end plate.

[0019] The housing may include a protruding upright section located only on one side of the battery cell stack. This provides sufficient flexibility to form welds on the housing and end plates.

[0020] On the side of the battery cell stack opposite the protruding upright section, the housing may contact the end plate along the stacking direction. When viewed along the stacking direction, the housing may be "located" above the end plate opposite the protruding upright section. This end plate may provide an abutment to the housing in the stacking direction. The end plate may also include a protruding section that is surrounded by the housing in the assembled state. This protruding section may provide an abutment to the housing in the radial direction (perpendicular to the stacking direction).

[0021] On the side of the battery cell stack opposite to the protruding upright section, when viewed along the stacking direction, the end plate extends beyond the housing in a plane perpendicular to the stacking direction; specifically, the end plate extends beyond the housing circumferentially in a plane perpendicular to the stacking direction. This achieves housing positioning and serves as an abutment in the aforementioned stacking direction. The end plate on this side of the stack can form the base of the assembly, and the area of ​​the end plate on this side of the stack is larger than that of the end plate on the opposite side.

[0022] On one side of the protruding upright section, a splash guard may be provided between the housing and the corresponding end plate. The splash guard may be made of a sealing rope that extends around the circumferential portion of the end plate and protrudes from the end plate, so that the sealing rope is compressed between the housing and the end plate.

[0023] A splash guard may be located between the weld and the stack cavity enclosed by the housing. The splash guard is configured to form a seal between the housing and the first and / or second end plates before the housing and the corresponding end plates are joined by the weld, thereby preventing welding spatter from entering the enclosed stack cavity.

[0024] The sealing rope in this invention is a flexible, elongated element that extends flexibly along the outer periphery of the end plate and conforms to the shape of the end plate's outer periphery. The diameter of the sealing rope can be compressed to a certain extent, or deformed in that direction. Good sealing contact can be achieved even if the housing and end plate are not uniformly aligned along the entire periphery of the end plate. The gap between the housing and the end plate may vary along the periphery. Using a flexible sealing rope can effectively compensate for this variation, particularly because the sealing rope can be compressed and / or deformed along its diametrical direction (the diameter extends perpendicular to the larger longitudinal extension of the sealing rope).

[0025] Sealing cords may include fiberglass. In particular, sealing cords may be fiberglass sealing cords. Such sealing cords have extremely high heat resistance, effectively prevent splashing, and do not release harmful substances within the enclosed stack cavity.

[0026] The sealing cord is located in a positioning groove that extends along the periphery of the connected end plate on one side of the protruding upright section. This positioning groove allows the sealing cord and end plate to be assembled before connection with the housing. The positioning groove holds the sealing cord in the correct position and facilitates manipulation of the end plate with the sealing cord, for example, by an assembly machine.

[0027] The positioning groove may have a first defining wall and a second defining wall defining the positioning groove along the stacking direction. At least one of the defining walls may be constituted by a separate element or part of a separate element, which is connected to the remainder of the connected end plate located on one side of the protruding upright section. In particular, the defining walls (e.g., separate pieces) may be connected in a detachable manner. During assembly, a sealing rope may be inserted into the positioning groove, and then the defining wall is attached, for example, by threading or welding, to ensure a firm alignment and positioning of the sealing rope on the end plate. Subsequently, the housing may be pressed onto the end plate radially (in the extending plane of the end plate; perpendicular to the stacking direction) and welded to secure the housing and end plate together.

[0028] The sealing cord can be configured as a closed loop, particularly a non-elastic closed loop. This design is especially advantageous when used in conjunction with a positioning groove, as the sealing cord can be securely fixed in place, and its construction and position effectively resist mechanical interference. In particular, an "openable" positioning groove with a limiting wall provided by an independent connector is advantageous because it facilitates the assembly of the closed loop sealing cord to the end plate.

[0029] The combination of the sealing cord and the protruding upright section of the housing also offers advantages, as the weld can be positioned within the area of ​​the protruding upright section, essentially "located" above the end plate. The thickness of the end plate can be selected to accommodate the dimensions of the sealing cord, without requiring additional thickness to achieve the connection between the end plate and the housing, since the weld can be positioned at the corner formed between the end plate and the protruding upright section. The sealing cord prevents spatter generated during welding from entering the enclosed stack cavity, thereby ensuring the reliability of the electrochemical cell assembly.

[0030] Further details, aspects and embodiments of the invention may be derived from the following description and drawings. Attached Figure Description

[0031] In the attached diagram: Figure 1 A perspective view of an embodiment of an uncased electrochemical battery assembly is shown; Figure 2 It shows a casing, according to Figure 1 A side view of the electrochemical battery assembly shown; Figure 3 It shows along Figure 2 A cross-sectional view taken from line III-III in the diagram; Figure 4 It shows Figure 3 Details of the central IV region; Figure 5 A portion of an alternative embodiment of an electrochemical battery assembly is shown. Detailed Implementation

[0032] In this specification and the accompanying drawings, repeated reference numerals are intended to indicate the same or similar features or elements.

[0033] Figure 1 An exemplary embodiment of an electrochemical battery assembly 10 is schematically illustrated. The electrochemical battery assembly 10 includes a first endplate assembly 12 having a first endplate 14, a second endplate assembly 16 having a second endplate 18, and a stack 20 of battery cells 22 (also referred to herein as “battery repeating cells”). Figure 1 The main purpose is to provide an overview of the electrochemical battery assembly 10 and its components through examples.

[0034] The stack 20 is disposed between the first endplate assembly 12 and the second endplate assembly 16. The stack 20 includes a plurality of battery repeating units 22, which are stacked on top of each other along the stacking direction 24. The arc-shaped arrow C indicates the circumferential direction. Figure 2 The arrow R in the diagram indicates the radial direction. As described above, the battery repeating unit 22 can be a fuel cell unit, an electrolyzer cell unit, or a reversible battery unit that includes an electrochemical active layer (not shown).

[0035] In the example shown, the second end plate 18 includes four through holes 26. The through holes 26 extend along the stacking direction 24 and form corresponding fluid ports 28 for conveying fluid between the exterior of the electrochemical cell assembly 10 and the stack 20 of the cell repeating unit 22. The location and number of the through holes 26 or the corresponding fluid ports 28 may vary.

[0036] In the illustrated embodiment, end plate assemblies 12 and 16 further include an insulating plate 30. The respective end plates 14, 18 and the insulating plate 30 are stacked on top of each other along the stacking direction 24. In the electrochemical cell assembly 10, the insulating plate 30 is located between the respective end plates 14, 18 and the stack 20 of the cell repeating unit 22 (e.g., see...). Figure 2 A).

[0037] In the assembled state, the stack 20 is preferably held in a compressed state between the first end plate assembly 12 and the second end plate assembly 16. For this purpose, the electrochemical cell assembly 10 may include additional compression devices (not shown) known in the art, such as pull rods, compression springs, or bolts. Compression may also be provided by a housing 32, which... Figure 1 Not shown in the image.

[0038] Figure 2 An example of such a housing 32 is shown, wherein the housing 32 includes a first skirt-shaped segment 34 and a second skirt-shaped segment 36. Both skirt-shaped segments 34 and 36 of the housing 32 are connected to a first end plate 14 via a first weld 38 and to a second end plate 18 via a second weld 40. The housing 32 surrounds the stack 20 and extends around the outer periphery of the battery cell 22 to enclose a stack cavity 42 in which the battery stack 20 is housed (see [link to documentation]). Figure 3 ). Figure 2 The configuration shown is as follows Figure 3 Middle Figure 2 Line III III. Cross-sectional view taken from the sample. (See image below.) Figure 3As shown, the second end plate 18 includes an inwardly biased (radially biased in a direction perpendicular to the stacking direction 24) protrusion 44 that provides an internal abutment 46 (in a radial direction perpendicular to the stacking direction 24) for the housing 32 or the two skirt-shaped sections 34 and 36.

[0039] exist Figure 2 and Figure 3 In the example, the first end plate 14 is surrounded by the skirt-shaped segments 34 and 36 of the housing 32, and the first end plate 14 extends beyond the housing 32 along the orientation of the stacking direction 24. Figure 3 (and Figure 4 In order to make the illustration clearer, the components arranged in the closed stack cavity 42 are not shown in the figure.

[0040] The housing 32 is provided with a protruding standing segment 48. This protruding standing segment 48 is formed by the portion of the housing 32 extending beyond the connected first end plate 14 along the stacking direction 24. A first weld 38 connecting the housing 32 or the first skirt-shaped segment 34 and the second skirt-shaped segment 36 of the housing 32 to the first end plate 14 is located on the protruding standing segment 48 of the housing 32 and is surrounded by the housing 32. The first weld 38 is located in the corner between the housing 32 and the first end plate 14.

[0041] Figure 4 Shown in magnified form Figure 3 Part IV, i.e., the area around the first weld 38, is shown in the figure. The spatter trap 50 is clearly shown in this illustration. In this embodiment, the spatter trap 50 is composed of a sealing cord 52. In this embodiment, the sealing cord 52 is provided with fiberglass cord, and in this example, the fiberglass cord is formed as a closed loop around the first end plate 14. Other types and configurations of sealing cords may also be used. The sealing cord 52 can be used as the spatter trap 50, or other types of spatter traps 50 may be used, or foreign objects may be prevented from entering the enclosed stack cavity 42 in other ways, for example, by selectively connecting the housing 32 and the end plate 14 in a spatter-free manner.

[0042] In the example shown herein, the first end plate 14 is provided with a positioning groove 54 for the sealing cord 52. The positioning groove 54 extends along the outer periphery of the first end plate 14. The positioning groove 54 extends along the circumferential portion of the end plate 14. The positioning groove 54 is located in the circumferential end face of the end plate 14. The positioning groove 54 is positioned on the circumferential end face of the end plate 14 to face the enclosed stacked cavity 42. The positioning groove 54 provides space for the sealing cord 52 and secures the sealing cord in place so that the sealing cord contacts the housing 32.

[0043] A sealing cord 52 is arranged around the circumferential portion of the first end plate 14 and extends outward from the first end plate 14, thereby compressing the sealing cord 52 between the housing 32 and the (connected) first end plate 14. The sealing cord 52 has a degree of flexibility, allowing it to be pressed into the positioning groove 54 during assembly when the housing is pressed radially inward before the weld 38 is formed. The sealing cord 52 forms circumferential contact with the housing 32, such that all gaps between the housing and the first end plate 14 are sealed by the sealing cord 52. This ensures that any spatter generated during the formation of the first weld 38 connecting the first end plate 14 to the housing 32 does not enter the closed stack cavity 42. Spatter is captured by the sealing cord 52, which constitutes the splash guard 50.

[0044] In the example shown, the construction of the splash guard 50 is described in conjunction with the first end plate 14, but a splash guard for the second end plate 18 can also be provided.

[0045] exist Figure 4 In the example shown, the first end plate 14, including the positioning groove 54, includes a removable element 56. The positioning groove 54 has an upper first defining wall 58 and a lower defining wall 60. In this example, since the lower second defining wall 60 is provided by the removable element 56, the lower second defining wall 60 is detachably connected to the remainder of the connected first end plate 14. By removing the removable element 56, the positioning groove can be "opened" to allow the installation of the sealing cord 52. The removable element 56 can also be configured as a separate element that is permanently attached (non-removable) to the first end plate 14 after the sealing cord 52 is introduced into the positioning groove 54.

[0046] During assembly, in the first step, before the removable component 56 is connected to the rest of the first end plate 14, the sealing cord 52 is inserted into the positioning groove 54. In the second step, the removable component 56 is attached to the first end plate 14. This attachment can be permanent, for example, by adhesive or welding, or it can be releasable, for example, by connecting bolts, screws, or snap-fit ​​devices. Afterward, the housing 32 is attached to the end plates 14 and 18, and the end plates 14 and 18 are permanently connected to the housing 32 via welds 38 and 40.

[0047] like Figure 4 As shown, the protruding upright section 48 of the housing 32 is also marked, and the first weld 38 surrounds the housing 32, which combines... Figure 3 As already described in [the text]. For example... Figure 4 As shown, the positioning groove 50 occupies a large portion of the thickness of the end plate 14. Nevertheless, the protruding upright section 48 still allows for the application of the weld 38.

[0048] Figure 5Another example of an electrochemical cell assembly 10 is shown, which has a housing 32 including a protruding upright section 48. The electrochemical cell assembly 10 is shown in the state before the second section 36 is attached. At this time, only the first section 34 of the housing 32 is arranged around the periphery of the stack 20 and the first end plate 14. A splash guard 50 is provided between the housing 32 and the first end plate, the splash guard 50 being provided by a sealing cord 52 extending around the first end plate 14. An electrical connector 62 is provided on the first end plate 14. The electrical connector 62 may alternatively be provided at other locations in the electrochemical cell assembly 10.

Claims

1. An electrochemical battery assembly (10), comprising: A first endplate assembly (12) having a first endplate (14); a second endplate assembly (16) having a second endplate (18); and a stack (20) of battery cells (22), the stack (20) comprising a plurality of battery cells (22) stacked together along a stacking direction (24), each of the plurality of battery cells (22) defining an outer periphery in a plane extending perpendicular to the stacking direction (24), the stack (20) of battery cells (22) being arranged between the first endplate (14) and the second endplate (18) along the stacking direction (24); and a housing (32) surrounding the stack (20) and extending around the outer periphery of the battery cells (22) to enclose a stack cavity (42), wherein the housing (32) is connected to the first endplate (14) and the second endplate (18). Its features are, The housing (32) extends along the stacking direction (24) beyond at least one of the connected first end plate (14) and / or second end plate (18), such that the housing (32) includes a protruding upright section (48).

2. The electrochemical battery assembly (10) according to the preceding claim, wherein, On one side of the stack (20) of the battery cell (22) having the protruding upright section (48), the housing (32) is connected to the corresponding end plate (14, 18) by welds (38, 40), such that the welds (38, 40) extend along the outer periphery of the end plate (14, 18) and are surrounded and connected to the housing, in particular the welds are connected to the protruding upright section (48) of the housing (32).

3. The electrochemical battery assembly (10) according to any one of the preceding claims, wherein, On one side of the stack (20) of the battery cell (22) having the protruding upright section (48), the housing (32) is connected to the corresponding end plate (14, 18) by welds (38, 40), the welds (38, 40) extending along the outer periphery of the end plate (14, 18) and located at the corner between the protruding upright section (48) formed on the housing (32) and the end plate (14, 18).

4. The electrochemical battery assembly (10) according to any one of the preceding claims, wherein, On one side of the stack (20) of the battery cell (22) having the protruding upright section (48), the housing (32) and the corresponding end plates (14, 18) are connected by welds (38, 40) formed by cold metal transition welding.

5. The electrochemical battery assembly (10) according to any one of the preceding claims, wherein, The housing (32) includes at least two skirt-shaped segments (34, 36) extending along the stacking direction (24).

6. The electrochemical battery assembly (10) according to any one of the preceding claims, wherein, The housing (32) includes at least one, particularly two, skirt-shaped segments (34, 36) that have a U-shaped cross-section when viewed along the stacking direction (24).

7. The electrochemical battery assembly (10) according to any one of the preceding claims, wherein, The protruding upright section (48) of the housing (32) extends beyond the corresponding end plates (14, 18) by a distance greater than the thickness of the end plates (14, 18).

8. The electrochemical battery assembly (10) according to any one of the preceding claims, wherein, The housing (32) includes a protruding upright section (48) located only on one side of the stack (20) of the battery cell (22).

9. The electrochemical battery assembly (10) according to the preceding claim, wherein, On the side opposite to the protruding upright section (48) of the stack (20) of the battery cell (22), the housing (32) contacts the end plate (14, 18) along the stacking direction.

10. The electrochemical battery assembly (10) according to any one of claims 8 or 9, wherein, On the side opposite to the protruding upright section (48) of the stack body (20) of the battery cell (22), when viewed along the stacking direction, the end plates (14, 18) extend beyond the housing (32) in a plane perpendicular to the stacking direction, and in particular, the end plates extend beyond the housing (32) around the entire circumference of the housing (32) in a plane perpendicular to the stacking direction.

11. The electrochemical battery assembly (10) according to any one of the preceding claims, wherein, On one side of the protruding upright section (48), a splash guard (50) is provided between the housing (32) and the corresponding end plates (14, 18), wherein the splash guard (50) is provided by a sealing rope (52) that extends around the circumferential portion of the end plates (14, 18) and extends out of the end plates, such that the sealing rope (52) is compressed between the housing (32) and the end plates (14, 18).

12. The electrochemical battery assembly (10) according to the preceding claim, wherein, The sealing rope (52) comprises glass fiber, and in particular, the sealing rope (52) is a glass fiber sealing rope (52).

13. The electrochemical cell assembly (10) according to any one of claims 11 and 12, wherein, The sealing rope (52) is located in the positioning groove (54), which extends along the periphery of the connected end plates (14, 18) located on one side of the protruding upright section.

14. The electrochemical cell assembly (10) according to any one of claims 11 to 13, wherein, The positioning groove (54) has a first defining wall (58) and a second defining wall (60) that define the positioning groove (54) along the stacking direction (24), and at least one of the defining walls (58, 60) is connected, in particular detachably connected, to the remainder of the connected first end plate and / or second end plate (14, 18).

15. The electrochemical cell assembly (10) according to any one of claims 11 to 14, wherein, The sealing rope (52) is configured as a closed loop, particularly a non-elastic closed loop.

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