RU2803926C1 - Bipolar fuel cell plate - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: bipolar plate of a fuel cell, which contains two identical thin-sheet elements with a corrugated relief. The elements of the bipolar plate are connected by contour welds with a preliminary rotation relative to each other by 180°, while the corrugated relief is made in an equilateral hexagonal active region in the form of rectilinear and wavy channels, with one collector located opposite each side of the hexagon. The wavelike and straight parts of the channels are connected to each other at the intersection points of the diagonals of the hexagon, where they repeatedly change directions by 60° with a total rotation of 180° around the center of symmetry with subsequent connection with wavelike parts with a simultaneous change of direction by 120°.

EFFECT: increasing the reliability of the bipolar plate, as well as expanding the layout capabilities.

6 cl, 6 dwg

Description

The invention relates to the field of direct conversion of chemical energy into electrical energy, in particular to the design of a bipolar plate of a fuel cell (FC).

There are known analogues of bipolar FC plates consisting of two thin-sheet elements connected (by soldering or welding) with an active region containing a corrugated relief on each element with the formation of channels outside for gases (fuel and oxidizer) and inside for a cooling medium, as well as manifolds for supplying gas and cooling media into the active region of bipolar FC plates (see, for example, patents RU 2516245 dated November 29, 2012; RU 2328060 dated November 23, 2006).

The design of a bipolar TE plate is also known (see patent RU 2723294 dated December 30, 2019), containing two identical thin-sheet metal elements connected by welding, with a preliminary rotation of 180° relative to each other. The latter contain in the middle part an active region of a rectangular shape with a corrugated relief in the form of wavy parallel channels. On the outer sides of the plates there are holes that form collectors when assembling the FC plates with each other, for supplying both gases (fuel and oxidizer) and a cooling medium.

The design of a bipolar TE plate is also known (see RF patent No. 2785834 dated 08/17/2022), containing two identical and connected by contour seams, with a preliminary rotation around the rotation axis by 180° relative to each other, metal thin-sheet elements, with an external contour, with an active an area containing corrugated relief in the form of straight and wavy channels, gas and cooling medium collectors communicating with the active area.

The specified design of a bipolar TE plate is the closest analogue of the claimed device in technical essence and is taken as a prototype.

The disadvantages of analogue technical solutions are:

1. The absence of the shape of the surface of the active region of the bipolar plate in the form of an equilateral regular hexagon does not make it possible to place one collector on each side, which reduces the uniformity of distribution of working media between the collectors and the active region and the reliability of the plate as part of the fuel cell in the fuel cell battery.

2. The absence of a center of symmetry and diagonals in the active region, one of which coincides with the rotation axis, does not allow the placement of gas collectors of the same name with a coolant collector between them at an angle of 120° on each side of the rotation axis, which reduces the layout capabilities of the formation areas with corrugated relief.

3. The absence of a regular equilateral hexagon with diagonals in the active region does not allow the gas medium channels to be made in the form of alternating rectilinear parts that change directions at the points of intersection with the diagonals and does not allow the elements to have wavy parts of the channels parallel to only one collector with a cooling medium with a monotonous decrease in the length of the wavy parts in the direction towards the axis of rotation. This does not make it possible to reduce the area of a complex section with wavy channels, which occupies more than 60% of the active region.

4. The absence of a center of symmetry in the active region does not allow the rectilinear parts of the channels, when changing directions, to perform a general rotation of 180° around the center of symmetry with subsequent connection with the wavy parts. This does not allow for a uniform layout of channels in areas with corrugated terrain.

5. The presence in the cooling medium cavity of variants of channel configurations of significant complexity with the general direction of the medium from the collector to the opposite collector can reduce the reliability when the cooling medium passes through the channels of the active region.

6. The external contour of the bipolar plate, which differs from a regular hexagon, does not allow creating a FC battery with the possibility of densely arranging it in a cavity of a hexagonal cross-section, or several FC batteries with each other. This significantly reduces layout capabilities.

7. The external contour of the bipolar plate, which differs from a circle, does not allow creating a FC battery with the possibility of densely arranging it in a cavity with a circular cross-section. This significantly reduces layout capabilities.

8. The absence of contour welds in the form of adjacent intersecting linear segments of seams, with a mismatch of the intersection points of the segments with the length boundary points of adjacent segments, can lead to significant welding deformations, which reduces the reliability of the bipolar plate.

The technical result of the proposed design of a bipolar TE plate, while eliminating the indicated disadvantages, is to simplify the design, increase reliability and expand layout capabilities.

This result is achieved due to the fact that a bipolar TE plate with two identical and connected contour welds, with a preliminary rotation around the rotation axis by 180° relative to each other, metal thin-sheet elements, with an external contour, with an active area containing a corrugated relief in the form rectilinear and wavy channels, gas and cooling medium collectors communicating with the active region, while the surface of the active region is made in the form of an equilateral regular hexagon. On each side of the hexagon there is one collector, two with fuel (hydrogen), two with oxidizer (air) and two with coolant. The rotation axis coincides with one of the diagonals and the center of symmetry of the hexagon. On both sides of the rotation axis and parallel to the axis there are manifolds with a cooling medium, each of them located between adjacent gas manifolds of the same name at an angle of 120°. The corrugated relief in the elements, between the collectors with the same gas medium, is made with channels parallel to the sides of the hexagon. The channels are made both in the form of straight parts and in the form of wavy parts. The latter are located only at one manifold with the cooling medium. The length of the wavy parts monotonically decreases towards the axis of rotation. The area of the area with wavy channels is about 16% of the area of the active region. The straight parts are connected to each other and change direction by 60° at the points of intersection with the diagonals of the hexagon. All channels with straight parts, when changing the directions of their parts, are made with a general rotation of 180° in one direction around the center of symmetry of the hexagon. After which the straight channels are smoothly connected to the wavy channels with a simultaneous change of direction by 120°.

The internal channels between the plate elements for the cooling medium are made with at least three types of sections. On one, the channels are formed when the rectilinear channels of one element cross the rectilinear channels of the second element. In the second, the channels are formed when the straight channels of one element longitudinally intersect the wavy channels of the second element in the areas between the peaks and troughs of the waves in each wave. In the third, the channels are formed when the straight channels of one plate coincide with the straight channels of another plate.

The outer contour of the plate is made in the shape of a regular hexagon with coinciding diagonals and a center of symmetry with the hexagon of the active region. Another design is also possible, in which the outer contour of the plate is made in the shape of a regular hexagon with the diagonals of the hexagon located between the diagonals of the hexagon of the active region.

The outer contour of the plate can also be made in the shape of a circle with a center coinciding with the center of symmetry of the hexagon of the active region.

Contour welding is carried out along the outer perimeter of the plate and around the gas manifolds. In this case, the welds are preferably made in the form of adjacent intersecting linear sections of seams. Moreover, the intersection points of the segments do not coincide with the points of the length boundaries of adjacent segments.

The claimed technical solution is illustrated with graphic materials, where:

Figure 1 shows a thin-sheet metal element of a bipolar FC plate with coinciding centers of symmetry and diagonals of hexagons of the active region and external contour;

Figure 2 shows a bipolar TE plate consisting of two elements connected by welding from figure 1;

Figure 3 shows a bipolar TE plate with diagonals of hexagons of the active region and the outer contour located between each other;

Figure 4 shows a bipolar TE plate with an external contour in the shape of a circle;

Figure 5 (element A from figure 2) shows a fragment of the area where straight channels intersect wavy channels between elements in the active region;

Figure 6 (element B from figure 2) shows a fragment of a contour weld with the intersection of the linear sections of the seams.

The bipolar FC plate consists of metal thin-sheet elements 1 with an active area 2 in the shape of a regular hexagon 3, which contains a corrugated relief in the form of parallel wave-like channels 4 and in the form of parallel straight channels 5. Opposite each side 6 of the hexagon of the active area 2 there are holes that form collectors 7, 8, 9, 10, 11, 12. Cooling medium manifolds 7 and 8 are located opposite each other, parallel to the axis of rotation 13 and between the gas manifolds of the same name 9 and 10 (hydrogen), adjacent to them, at an angle of 120°, 11 and 12 (air). The axis of rotation 13 is also one of the diagonals 14 of the hexagonal active region 2 with a center of symmetry 15. The wavy channels 4 are made in parts 32 and are located in the elements 1 parallel to only one side 6 of the hexagon 3 opposite one coolant collector 7. The length of the parts 32 channels 4 is in series decreases from the manifold 7 to the axis of rotation 13. The straight channels 5 are made, from the gas manifold 9, in parts 16 parallel to the sides of the hexagon 3 and are connected to each other at points 17 of intersection with the diagonals 14 with a simultaneous change of directions at angles of 60° and with a general rotation 180° in one direction around the center of symmetry 15 until connected to the wavy parts 32 with a simultaneous change of direction by 120° and end at the gas manifold 10. The cavities of the gas manifolds 9, 10, 11, 12 are connected by communication channels 18 with the active area 2 from the outside sides of the elements 1. The cavities of the collectors 7, 8 with the cooling medium are connected to the active area 2, between the elements 1, communication channels 19. Along the outer contour of the elements 1 and around all the collectors, sealing grooves 20 and 21 are made, respectively, and these grooves coincide with each other each other from the side of the external contour 28. Elements 1 are hermetically connected to each other, along the outer perimeter and around the gas collectors, by contour welds 22. Before welding, elements 1 are rotated relative to each other by 180° around the axis of rotation 13 and are mutually fixed using centering holes 27 In the cavity of the cooling medium, in the active region 2 of the bipolar plate, three types of sections 23, 24 and 33 are formed for the movement of the cooling medium, for example, from the collector 7 to the collector 8 in the direction perpendicular to the axis of rotation 13. In the section 23 there are straight channels 5 of one element 1 are crossed longitudinally and repeatedly by wave-like channels 4 of another element 1 between the peaks 25 and troughs 26 in each wave. In section 24, the rectilinear channels 5 of one element 1 cross transversely the channels 5 of another element 1. In section 33, the rectilinear channels 5 of one element 1 coincide with the rectilinear channels 5 of another element 1. The outer contour 28 of the bipolar plate can be made:

- in the shape of a regular hexagon with coinciding diagonals 14 and a center of symmetry 15 of hexagon 3;

- in the form of a regular hexagon with a common center of symmetry 15 with hexagon 3 of active area 2 and with diagonals 14 located between the diagonals of hexagon 3 of active area 2;

- in the shape of a circle with a center coinciding with the center of symmetry 15 of the hexagon 3 of the active area 2.

The contour welds 22 are made in the form of adjacent intersecting linear sections 29 of the seams. Points 30, intersections of segments 29, do not coincide with points 31 of the length boundaries of adjacent segments 29.

A bipolar FC plate can only operate as part of a FC battery, where the specified FC plates must alternate with membrane-electrode units (MEB) (not shown in the drawings). On the one hand, the MEA forms, with the bipolar FC plates, cavities of fuel (hydrogen) in parts 16 and 32 of channels 4 and 5, on the one hand, active region 2, on the other hand, cavities of the oxidizer (air) also in parts 16 and 32 of channels 4 and 5 active area 2. Sealing, both between the cavities and with the external environment, is carried out using gaskets (not shown) in the sealing grooves 20 and 21 when the fuel cell is compressed into a single package in the battery. The spatial position of the bipolar FC plates can be vertical, where the coolant collectors 7 and 8 should be located, respectively, below and above, or horizontal. When the plates are arranged vertically, the cooling medium enters through the lower manifold 7, and the exit through the upper manifold 8, which guarantees air removal in the channels of the cooling medium cavity. In this case, the entry and exit of gaseous media can be made between collectors 9 and 10 (hydrogen) and 11 and 12 (air) in any sequence. With a horizontal arrangement of the plates, the inlet and outlet of all media can be on either side of the collectors. The movement of a gaseous medium, for example, hydrogen, within the plate, can begin from the input manifold 9, then through the communication channels 18 the gas enters the outer surface of the active region 2 in the element 1, then into the straight channels 5, where it moves along the straight parts 16 parallel to the sides 6 hexagon 3 of the active area 2 with a change in direction by 60° at the points 17 of intersection with the diagonals 14 of the hexagon 3. With such a change in the direction of movement in the rectilinear channels 5, the overall rotation of the gas in one direction, around the center 15 of symmetry of the hexagon 3, reaches 180° . After which, gas from parts 16 of straight channels 5 smoothly passes into parts of 32 wave-shaped channels 4 with a change in direction by 120°, after which, through channels 18 messages, it exits into the output manifold 10. The movement of another gaseous medium, air, begins, for example, with input collector 11 and ends in the output collector 12. In this case, the composition of the channels between these collectors completely coincides with the previous description of the channels for hydrogen, but with the location of the channels on the back side of the fuel cell plate. The movement of the cooling medium begins from the input manifold 7, then through the channels 19 messages into the active area 2 with three types of sections 23, 24 and 33. In section 23, the movement occurs along the channels formed by the longitudinal intersection of the straight parts 16 of the channels 5 of one element 1, wavy parts 32 channels 4 of the second element 1 between the peaks 25 and troughs 26 of the waves in each wave. In section 24, the movement occurs along channels formed by the transverse intersection of the straight parts 16 of channels 5 of one element 1 with similar channels in the second element 1. In section 33, movement occurs along the rectilinear parts 16 of channels 5 that coincide with both elements 1. Next, the cooling medium moves through the channels 19 messages to output collector 8.

The proposed bipolar TE plate allows achieving the following results:

1. Simplify the design by significantly reducing the area occupied by wave-shaped channels in the active region.

2. Increase operational reliability due to:

- uniform arrangement of collectors with working media around the perimeter of the hexagonal active region;

- simplifying the design of channels for the cooling medium in the active region;

- elimination of welding deformations of the bipolar plate of the fuel cell.

3. Increase layout capabilities due to:

- location of gas manifolds of the same name, with a coolant manifold between them, on each side of the rotation axis;

- changing the directions of parts of rectilinear channels and their general rotation by 180° around the center of symmetry of the hexagon of the active region;

- making the outer contour of the bipolar FC plate in the shape of a regular hexagon or circle to allow a dense arrangement of the FC battery with the specified plates in cavities with a hexagonal or circular cross-section.

Claims (6)

1. Bipolar plate of a fuel cell containing two identical and connected by contour welds with a preliminary rotation around the rotation axis by 180° relative to each other, metal thin-sheet elements, with an external contour, with an active region containing a corrugated relief in the form of straight and wavy channels, collectors, gas and cooling media communicating with the active area, characterized in that the surface of the active area is made in the form of an equilateral regular hexagon with one collector located on each side, with the axis of rotation coinciding with one of the diagonals and the center of symmetry of the hexagon, with In this case, in the plate, on both sides of the rotation axis and parallel to the latter, there are collectors with a cooling medium, and each of them is located between adjacent gas collectors of the same name, while the corrugated relief in the elements, between the collectors with the same gas medium, is made in the form parts of channels parallel to the sides of the hexagon, both straight parts and wavy parts located only at one collector with the cooling medium, the length of the latter decreasing towards the axis of rotation, while the straight parts are connected to each other and change directions by 60° at the intersection points with hexagon diagonals, while all channels with straight parts, when changing the directions of the parts, are made with a general rotation of 180° in one direction around the center of symmetry of the hexagon and then smoothly connected to parts of the wavy channels with a simultaneous change of direction by 120°, while the internal channels between the plate elements for the cooling medium are made at the intersection of the corrugated reliefs of the elements. 2. Bipolar plate according to claim 1, characterized in that the internal channels between the elements of the plate for the cooling medium are made with at least three types of sections, on one - when the straight channels of one element cross transversely with the straight channels of the second element, on the second - when the straight channels of one element longitudinally intersect the wavy channels of the second element between the peaks and troughs of the waves in each wave, on the third - when the straight channels of both elements coincide. 3. Bipolar plate according to claim 1, characterized in that the outer contour of the plate is made in the shape of a regular hexagon with coinciding diagonals and a center of symmetry with the hexagon of the active region. 4. Bipolar plate according to claim 1, characterized in that the outer contour of the plate is made in the shape of a regular hexagon with hexagon diagonals located between the diagonals of the active region hexagon. 5. Bipolar plate according to claim 1, characterized in that the outer contour of the plate is made in the shape of a circle with a center coinciding with the center of symmetry of the hexagon of the active region. 6. Bipolar plate according to any one of paragraphs. 1-5, characterized in that the contour welds are made in the form of adjacent intersecting linear sections of seams, and the intersection points of the seams do not coincide with the points of the length boundaries of adjacent sections.