JP2024018349A - Flow passage member, electrochemical cell, and electrochemical cell apparatus - Google Patents

Abstract

To provide a flow passage member, an electrochemical cell, and an electrochemical cell apparatus, each of which exhibits improved performance.SOLUTION: An electrochemical cell apparatus comprises a lamination of an electrolyte layer 3, a first electrode layer 4, and a flow passage member 6. The flow passage member 6 comprises a first gas passage 60a and a liquid passage 60c. The first gas passage 60a is situated in a first part 601a facing the first electrode layer 4 of a first surface 601 of the flow passage member 6. The liquid passage 60c is situated in a second part 601b surrounding the first part 601a in the first surface 601.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The disclosed embodiments relate to flow path members, electrochemical cells, and electrochemical cell devices.

Conventionally, technologies have been proposed that reversibly switch between water electrolysis and power generation using a single electrochemical cell.

JP 2018-78098 Publication

However, in the conventional technology, there is room for improvement, for example, in improving the performance of channel members located at both ends of an electrochemical cell and supplying fluid to the element section.

One aspect of the embodiments aims to provide a channel member, an electrochemical cell, and an electrochemical cell device that can improve performance.

A flow path member according to one aspect of the embodiment includes a first gas flow path and a liquid flow path. The first gas flow path is located at a first portion of the first surface of the flow path member. The liquid flow path is located in a second portion surrounding the first portion on the first surface.

Further, the electrochemical cell of the present disclosure includes an electrolyte layer, a first electrode layer, a second electrode layer, a first separator, and a second separator. The electrolyte layer has ionic conductivity. The first electrode layer and the second electrode layer face each other with the electrolyte layer in between. The first separator is located on the opposite side of the electrolyte layer across the first electrode layer. The second separator is located on the opposite side of the electrolyte layer with the second electrode layer in between. At least one of the first separator and the second separator is the channel member described above.

Further, an electrochemical cell device of the present disclosure includes a cell stack including the electrochemical cell described above.

According to one aspect of the embodiment, it is possible to provide a channel member, an electrochemical cell, and an electrochemical cell device that can improve performance.

FIG. 1 is a diagram schematically showing an electrochemical cell device according to an embodiment. FIG. 2 is a cross-sectional view schematically explaining the flow path member according to the first embodiment. FIG. 3 is a plan view schematically showing the flow path member according to the first embodiment. FIG. 4 is a plan view schematically showing the flow path member according to the first embodiment. FIG. 5 is a cross-sectional view schematically showing the flow path member according to the first embodiment. FIG. 6 is a sectional view schematically illustrating a flow path member according to the second embodiment. FIG. 7 is a plan view schematically showing a flow path member according to the second embodiment. FIG. 8 is a plan view schematically showing a flow path member according to the second embodiment. FIG. 9 is a cross-sectional view schematically showing a flow path member according to the second embodiment. FIG. 10 is a plan view schematically showing a flow path member according to the third embodiment. FIG. 11 is a plan view schematically showing a flow path member according to the third embodiment. FIG. 12 is a cross-sectional view schematically showing a flow path member according to the third embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a channel member, an electrochemical cell, and an electrochemical cell device disclosed in the present application will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below.

In order to make the explanation easier to understand, FIG. 1 shows a three-dimensional orthogonal coordinate system including a Z-axis with the vertically upward direction being the positive direction and the vertically downward direction being the negative direction. Such an orthogonal coordinate system may also be shown in other drawings used in the description below. Further, the same components as those of the electrochemical cell device 10 shown in FIG. 1 are given the same reference numerals, and the description thereof will be omitted or simplified.

Furthermore, it should be noted that the drawings are schematic, and the dimensional relationship of each element, the ratio of each element, etc. may differ from reality. Furthermore, drawings may include portions that differ in dimensional relationships, ratios, and the like.

<Embodiment>
FIG. 1 is a diagram schematically showing an electrochemical cell device according to an embodiment. As shown in FIG. 1, the electrochemical cell device 10 includes a plurality of electrochemical cells 1 and an end plate 7. The electrochemical cell device 10 has a cell stack including a plurality of electrochemical cells 1. The end plates 7 are members located at both ends of such a cell stack.

The electrochemical cell 1 includes an element section 2 and a separator 6. The element section 2 includes an electrolyte layer 3, a first electrode layer 4, and a second electrode layer 5.

The electrolyte layer 3 contains an electrolyte having ionic conductivity. As the electrolyte having ionic conductivity, for example, a solid polymer electrolyte, a polymer gel electrolyte, an inorganic solid electrolyte, etc. can be used. The solid polymer electrolyte may contain, for example, an electrolyte having proton (H ⁺ ) conductivity, that is, a perfluorosulfonic acid electrolyte such as Nafion (registered trademark), which is an acidic electrolyte. Further, the electrolyte layer 3 may contain water. Note that the electrolyte layer 3 is dense and does not easily allow gases such as hydrogen (H ₂ ) and oxygen (O ₂ ) to pass therethrough. Electrolyte layer 3 may further contain a binder.

The first electrode layer 4 contains, for example, an oxygen reduction catalyst and/or an oxygen generation catalyst. The oxygen reduction catalyst, for example, reduces oxygen supplied to the first electrode layer 4 to generate water. For example, platinum (Pt) can be used as the oxygen reduction catalyst. The oxygen generating catalyst may be, for example, a supported catalyst supported on a carrier. The carrier may be, for example, a carbon material, SnO ₂ or other conductive oxide.

The oxygen generating catalyst generates oxygen using, for example, water supplied to the first electrode layer 4. As the oxygen generation catalyst, for example, iridium oxide (IrO _x ) can be used. The oxygen generating catalyst may be used alone as catalyst particles, for example, or may be a supported catalyst supported on a carrier. The carrier may be, for example, a carbon material, SnO ₂ or other conductive oxide.

For example, the first electrode layer 4 reduces oxygen supplied from the separator 6 during power generation to generate water. Further, the first electrode layer 4 decomposes water supplied through the electrolyte layer 3 during water electrolysis, for example, and generates oxygen.

The first electrode layer 4 may include a diffusion layer having gas permeability. Further, the first electrode layer 4 may include a water-repellent layer having water-repellent properties.

The second electrode layer 5 may contain, for example, a hydrogen oxidation catalyst and/or a hydrogen generation catalyst. The hydrogen oxidation catalyst generates water using, for example, hydrogen supplied to the second electrode layer 5. Further, the hydrogen generation catalyst, for example, decomposes water supplied to the second electrode layer 5 and generates hydrogen. As such a hydrogen oxidation catalyst and/or hydrogen generation catalyst, for example, platinum (Pt) can be used. The hydrogen oxidation catalyst and/or the hydrogen generation catalyst may be used alone as catalyst particles, or may be a supported catalyst supported on a carrier, for example. The carrier may be, for example, a carbon material, SnO ₂ or other conductive oxide.

For example, the second electrode layer 5 oxidizes hydrogen supplied from the separator 6 during power generation to generate water. Further, the catalyst layer 5b decomposes water supplied through the electrolyte layer 3 during water electrolysis, for example, and generates hydrogen.

The second electrode layer 5 may include a diffusion layer having gas permeability. Further, the second electrode layer 5 may include a water-repellent layer having water-repellent properties.

Note that the element portion 2 may be rectangular or circular in plan view.

The separator 6 is positioned so as to sandwich the element section 2 therebetween. Separator 6 is located between adjacent element parts 2. The separator 6 has conductivity and electrically connects adjacent electrochemical cells 1. The material of the separator 6 may be, for example, metal. When the separator 6 is coated with an acid-resistant metal such as Pt or Au, the Fenton reaction is less likely to occur.

Further, the separator 6 is a flow path member having a plurality of flow paths. The separator 6a facing the first electrode layer 4 has, for example, a first gas flow path that supplies oxygen-containing gas to the first electrode layer 4 or recovers oxygen from the first electrode layer 4. The separator 6b facing the second electrode layer 5 has a second gas flow path that supplies hydrogen gas to the second electrode layer 5 or recovers hydrogen from the second electrode layer 5, for example. The separator 6 may have a liquid flow path that supplies water to the electrolyte layer 3 or recovers water from the electrolyte layer 3, for example.

[First embodiment]
FIG. 2 is a cross-sectional view schematically explaining the flow path member according to the first embodiment. As shown in FIG. 2, the separator 6 includes a first gas flow path 60a and a liquid flow path 60c.

The first gas flow path 60a is located at a first portion 601a of the first surface 601 facing the first electrode layer 4. The first gas flow path 60a supplies the first gas to the first electrode layer 4 or recovers the first gas from the first electrode layer 4. The first gas contains oxygen. The first gas may be air, for example.

The liquid flow path 60c is located on the first surface 601 at a second portion 601b surrounding the first portion 601a where the first gas flow path 60a is located. The liquid flow path 60c faces a portion of the electrolyte layer 3 adjacent to the first electrode layer 4 located around the first electrode layer 4. In other words, the first surface 601 has a first portion 601a facing the first electrode layer 4 and a second portion 602b surrounding the first portion 601a and facing the electrolyte layer 3. The liquid flow path 60c supplies water to the electrolyte layer 3 or recovers water from the electrolyte layer 3. Further, the liquid flow path 60c may discharge water collected from the electrolyte layer 3 to the outside.

A liquid 20 containing water is flowing through the liquid channel 60c. The liquid 20 may be, for example, water or an electrolyte. As the electrolyte, for example, an aqueous solution containing a base such as sodium hydroxide (NaOH) or potassium hydroxide (KOH), or an aqueous solution containing an acid such as hydrochloric acid (HCl) or sulfuric acid (H ₂ SO ₄ ) can be used. can. The electrolytic solution can be appropriately selected depending on the properties of the electrolyte (proton conductivity or hydroxide ion conductivity) that the electrolyte layer 3 has. The liquid flow path 60c may have acid resistance, alkali resistance, etc. as necessary.

As described above, since the separator 6 has the liquid flow path 60c around the first gas flow path 60a, water can pass through the slit provided in the first electrode layer 4, as in the form disclosed in Patent Document 1, for example. The structure is simplified compared to cases where the first gas and/or moisture is supplied and recovered, and leakage of the first gas and/or moisture is less likely to occur. Therefore, performance can be improved.

The structure of the separator 6 according to the first embodiment will be further explained using FIGS. 3 to 5. FIG. 3 is a plan view schematically showing the flow path member according to the first embodiment. FIG. 4 is a plan view schematically showing the flow path member according to the first embodiment. FIG. 5 is a cross-sectional view schematically showing the flow path member according to the first embodiment.

Separator 6 has a first surface 601 and a second surface 602. The first surface 601 is arranged on the first electrode layer 4 side of the electrochemical cell 1A as the first cell, and the second surface 602 is arranged on the electrochemical cell 1B as the second cell located next to the electrochemical cell 1A. is arranged on the second electrode layer 5 side.

The separator 6 has through holes 8 and 9 that penetrate in the thickness direction (X-axis direction). The through hole 8 is a supply port for supplying gas or water to the element section 2 of the electrochemical cell 1 through a flow path. The through hole 9 is an outlet for discharging gas or water from the element section 2 through a flow path. Note that the flow path includes a first gas flow path 60a, a second gas flow path 60b, and a liquid flow path 60c.

Through hole 8 includes supply ports 8a to 8c. The through hole 9 includes discharge ports 9a to 9c. The first gas flows through the supply port 8a and the discharge port 9a. A second gas containing hydrogen flows through the supply port 8b and the discharge port 9b. A liquid containing water flows through the supply port 8c and the discharge port 9c.

The supply port 8a and the discharge port 9a are connected to the first gas flow path 60a. The first gas flow path 60a has a flow path 61 and a flow path 62. The flow path 61 is a space located inside the separator 6 and extending along the YZ plane. The flow path 62 is a slit-shaped gas flow path opened in the first surface 601, extends in the thickness direction (X-axis direction), and communicates with the flow path 61. The flow paths 61 and 62 are not limited to the illustrated shapes.

The first gas is introduced into the flow path 61 located inside the separator 6 from the supply port 8a. A part of the first gas introduced into the flow path 61 is supplied from the flow path 62 to the first electrode layer 4 (see FIG. 5). The remainder of the first gas introduced into the channel 61 and the reacted first gas recovered from the first electrode layer 4 are discharged through the channel 61 to the outlet 9a.

The supply port 8c and the discharge port 9c are connected to the liquid flow path 60c. The liquid channel 60c has a channel 65 and a channel 66. The flow path 65 is located inside the separator 6 and extends along the YZ plane. The flow path 66 annularly surrounds the flow path 62 in plan view. Further, the flow path 66 communicates with the flow path 65.

Liquid such as water is introduced into the flow path 65 located inside the separator 6 from the supply port 8c. The liquid introduced into the flow path 65 is supplied to the electrolyte layer 3 (see FIG. 2) from the flow path 66. The remainder of the liquid introduced into the channel 66 and the liquid recovered from the electrolyte layer 3 are discharged through the channel 65 to the outlet 9c.

The flow path 65 and the flow path 66 may have the same or different widths when viewed in plan. For example, if the width of the flow path 66 is made larger than the width of the flow path 65, water can be quickly supplied to the electrolyte layer 3, so that the performance is further improved.

The supply port 8b and the discharge port 9b are connected to the second gas flow path 60b. The second gas flow path 60b has a flow path 63 and a flow path 64. The flow path 63 is located inside the separator 6 and extends along the YZ plane. The flow path 64 is a gas flow path that is open to the second surface 602, extends in the thickness direction (X-axis direction), and communicates with the flow path 63. The flow path 64 has a meandering shape in plan view. The flow paths 63 and 64 are not limited to the illustrated shapes.

The second gas is introduced into the flow path 63 located inside the separator 6 from the supply port 8b. A part of the second gas introduced into the flow path 63 is supplied from the flow path 64 to the second electrode layer 5 (see FIG. 5). The remainder of the second gas introduced into the channel 63 and the reacted second gas recovered from the second electrode layer 5 are discharged through the channel 63 to the outlet 9b.

Note that the space between the separator 6 and the element section 2 may be sealed air-tightly or liquid-tightly using a sealing member or the like, if necessary. For example, the reliability of the electrochemical cell device 10 can be improved by sealing the space between the flow path 62 and the flow path 66 shown in FIG. 3, the outer peripheral portion of the flow path 66, and the outer peripheral portion of the flow path 64 shown in FIG. improves.

In this way, the separator 6 according to this embodiment includes the first gas flow path 60a and the liquid flow path 60c. The first gas flow path 60a is located at a first portion 601a of the first surface 601. The liquid flow path 60c is located on the first surface 601 at a second portion 601b surrounding the first portion 601a. Thereby, the separator 6 can have improved performance.

[Second embodiment]
FIG. 6 is a sectional view schematically illustrating a flow path member according to the second embodiment. As shown in FIG. 6, the separator 6 has a metal portion 6A and a resin portion 6B.

The metal portion 6A is located at a first portion 601a of the first surface 601 facing the first electrode layer 4. The resin portion 6B is located in a portion that does not face the first electrode layer 4, such as the second portion 601b of the first surface 601. The first gas flow path 60a is located so as to penetrate the metal portion 6A. In this way, the separator 6 may be composed of two or more members having different characteristics.

FIG. 7 is a plan view schematically showing a flow path member according to the second embodiment. FIG. 8 is a plan view schematically showing a flow path member according to the second embodiment. FIG. 9 is a cross-sectional view schematically showing a flow path member according to the second embodiment.

As shown in FIG. 7, the separator 6 has a metal portion 6A located inside the flow path 66 and a resin portion 6B located outside the flow path 66 on the first surface 601. The flow path 66 may be formed by the resin portion 6B.

Further, as shown in FIG. 8, the second surface 602 of the separator 6 may have a metal portion 6A and a resin portion 6B, similarly to the first surface 601.

The material of the metal portion 6A may be, for example, metal. If the metal portion 6A has an acid-resistant metal such as Pt or Au on its surface, the Fenton reaction is less likely to occur.

Further, the material of the resin portion 6B may be, for example, an acrylic resin or a fluororesin resin having acid resistance and heat resistance. The resin portion 6B may have conductivity or insulation. When the metal part 6A includes a first metal part 6A1 located on the first surface 601 and a second metal part 6A2 located on the second surface 602, and the resin part 6B has insulation properties, for example, as shown in FIG. A through hole 67 is provided between the first metal portion 6A1 and the second metal portion 6A2, and a conductor portion 68 is positioned inside the through hole 67 to electrically connect the first metal portion 6A1 and the second metal portion 6A2. You may let them. Thereby, the adjacent electrochemical cells 1 can be properly electrically connected. The conductor portion 68 may be, for example, a lead wire.

As described above, since the separator 6 has the resin portion 6B, it is expected that the weight of the electrochemical cell device 10 will be reduced, for example. Furthermore, the degree of freedom in designing the separator 6 is increased.

[Third embodiment]
FIG. 10 is a plan view schematically showing a flow path member according to the third embodiment. FIG. 11 is a plan view schematically showing a flow path member according to the third embodiment. FIG. 12 is a cross-sectional view schematically showing a flow path member according to the third embodiment.

The separator 6 according to this embodiment differs from the separators 6 according to the above-described embodiments in that the separator 6 is located inside the separator 6 and does not have a flow path extending along the YZ plane.

The first gas flow path 60a has a flow path 62A (first flow path) located on the first surface 601 and a flow path 61A (second flow path) located on the second surface 602. The flow path 62A and the flow path 61A are connected through a through hole 69 (third flow path) that penetrates the separator 6 in the thickness direction.

Note that, as shown in FIG. 12, in the electrochemical cell device 10 according to the present embodiment, the second electrode layer 5 facing the second surface 602 is smaller in plan view than the first electrode layer 4 facing the first surface 601. The area when doing so may be small. This makes it easier to appropriately position the through hole 69.

The liquid flow path 60c has a flow path 65A located on the first surface 601 and connected to the flow path 66. Further, the second gas flow path 60b has flow paths 63A and 64A located on the second surface 602. The flow path 64A is a portion facing the second electrode layer 5. The flow path 63A connects between the supply port 8b and the flow path 64A, and between the flow path 64A and the discharge port 9b. The area of the flow paths 63A and 64A, which are the portions located on the second surface 602 of the second gas flow path 60b, is larger than the area of the flow path 62A, which is the portion of the first gas flow path 60a that faces the first electrode layer 4. It can be small. Further, the area of the flow path 64A, which is the portion of the second gas flow path 60b facing the second electrode layer 5, is the area of the flow path 62A, which is the portion of the first gas flow path 60a, which is the portion facing the first electrode layer 4. May be smaller.

In this manner, the separator 6 according to the present embodiment does not have a flow path inside the separator 6, so that the strength of the separator 6 is improved. Further, since there is no need to provide a flow path inside the separator 6, the separator 6 can be easily manufactured.

<Method for manufacturing channel member>
Separator 6 can be produced by a conventionally known method. For example, each channel may be produced using a three-dimensional printer or the like. Furthermore, if the separator 6 is made of metal, for example, a plurality of thin plates may be laminated and joined together with a sealant or the like, or a through hole may be formed in the block and then only the hole on the outside may be closed.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit thereof. For example, the second gas may be caused to flow through the first gas flow path 60a, and the first gas may be caused to flow through the second gas flow path 60b. In such a case, the arrangement of the element section 2 may be changed depending on the flow of the first gas and the second gas.

Further, in each of the embodiments described above, the separator 6 is illustrated as having a rectangular shape in plan view, but the separator 6 is not limited to this, and may have a circular shape or a polygonal shape, for example.

Further, the flow path structure of the separator 6 according to the third embodiment may be adopted as the separator 6 according to the second embodiment.

Further, in each of the embodiments described above, the through hole 8 is a supply port, and the through hole 9 is a discharge port, but the supply port and the discharge port may be replaced. Further, the separator 6 may have a plurality of first gas flow paths 60a and a plurality of second gas flow paths 60b, and the number of through holes 8 and 9 may be increased accordingly.

As described above, (1) the flow path member according to the embodiment includes a first gas flow path located at a first portion on the first surface, and a second gas flow path located at a second portion surrounding the first portion on the first surface. and a liquid flow path.

(2) The flow path member described in (1) above may include a second gas flow path on a second surface located on the opposite side of the first surface.

(3) The channel member according to (2) above may include a resin portion, a first metal portion located at the first portion, and a second metal portion located at the second surface. good.

(4) The channel member described in (3) above may include a conductor portion that electrically connects the first metal portion and the second metal portion.

(5) The first gas flow path described in (2) to (4) above includes a first flow path located on the first surface and a second gas flow path located on the second surface. It may have a second flow path that does not communicate with the flow path, and a third flow path that penetrates the flow path member in the thickness direction and connects the first flow path and the second flow path.

(6) In the flow path member according to (5) above, when viewed from above, the area of the portion located on the second surface of the second gas flow path is The area may be smaller than the area of the portion located on one surface.

(7) The electrochemical cell according to the embodiment includes an electrolyte layer having ion conductivity, a first electrode layer and a second electrode layer facing each other with the electrolyte layer in between, and A first separator located on the opposite side of the electrolyte layer, and a second separator located on the opposite side of the electrolyte layer with the second electrode layer in between, the first separator and the second separator, At least one may be the channel member described in any one of (1) to (6) above.

Further, (8) the electrochemical cell device according to the embodiment may include a cell stack including the electrochemical cell described in (7) above.

Further advantages and modifications can be easily deduced by those skilled in the art. Therefore, the broader aspects of this disclosure are not limited to the specific details and representative embodiments shown and described above. Accordingly, various changes may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

1 Electrochemical cell 2 Element part 3 Electrolyte layer 4 First electrode layer 5 Second electrode layer 6 Separator 7 End plate 10 Electrochemical cell device

Claims (8)

a first gas flow path located in a first portion of the first surface;
and a liquid flow path located at a second portion surrounding the first portion on the first surface. The flow path member according to claim 1, further comprising a second gas flow path on a second surface located on the opposite side of the first surface. A resin part,
The channel member according to claim 2, comprising a first metal part located at the first portion and a second metal part located at the second surface. The channel member according to claim 3, further comprising a conductor portion that electrically connects the first metal portion and the second metal portion. The first gas flow path includes a first flow path located on the first surface, a second flow path located on the second surface that does not communicate with the second gas flow path, and a thickness of the flow path member. The flow path member according to claim 2, further comprising a third flow path that penetrates in the direction and connects the first flow path and the second flow path. The area of the portion of the second gas flow path located on the second surface is smaller than the area of the portion of the first gas flow path located on the first surface in plan view. Channel member. an electrolyte layer having ionic conductivity;
a first electrode layer and a second electrode layer facing each other with the electrolyte layer in between;
a first separator located on the opposite side of the electrolyte layer with the first electrode layer in between;
a second separator located on the opposite side of the electrolyte layer with the second electrode layer in between;
An electrochemical cell, wherein at least one of the first separator and the second separator is the channel member according to any one of claims 1 to 6. An electrochemical cell device comprising a cell stack comprising the electrochemical cell according to claim 7.

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