Cell unit

Abstract

To provide a cell unit that is simple in design and can be used under high pressure.SOLUTION: A cell unit 2 comprises a substrate 10 defining first and second surfaces 11 and 12 opposite to each other, a hole 13 that passes through from the first surface 11 to the second surface 12, a membrane 21 disposed within the hole 13 to partition it into a first space 15 on the first surface 11 side and a second space 16 on the second surface 12 side, a first flow passage 40 formed in the substrate 10 to introduce a first fluid into the first space 15, a second flow passage 42 formed in the substrate 10 to lead out a second fluid from the second space 16, a first gasket 50 disposed on the first surface 11 to surround the first space 15 and the first flow passage 40, and a second gasket 51 disposed on the first surface 11 to surround the second flow passage 42 on the outside of the first gasket 50.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a cell unit. [Background technology]

[0002] For example, Patent Document 1 discloses a water electrolysis device, which generates hydrogen by splitting water into oxygen and hydrogen using electrical power. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-117140 Summary of the Invention [Problem to be solved by the invention]

[0004] To increase the efficiency of hydrogen production, it is necessary to generate hydrogen under high pressure, but the design of a water electrolysis device becomes complicated when used under high pressure.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a cell unit that has a simple design and can be used under high pressure. [Means for solving the problem]

[0006] A cell unit according to one embodiment of the present invention comprises a substrate defining a first surface and a second surface facing each other, a hole penetrating from the first surface to the second surface, a membrane disposed within the hole and separating the hole into a first space on the first surface side and a second space on the second surface side, a first flow path formed in the substrate for introducing a first fluid into the first space, a second flow path formed in the substrate for guiding a second fluid from the second space, a first gasket disposed on the first surface and surrounding the first space and the first flow path, and a second gasket disposed on the first surface and surrounding the second flow path outside the first gasket.

[0007] A cell unit according to one embodiment of the present invention comprises a third gasket arranged on the second surface and surrounding the second space and the second flow path, and a fourth gasket arranged on the second surface and surrounding the first flow path outside the third gasket.

[0008] A cell unit according to one aspect of the present invention includes a third flow path formed in the base material for leading the first fluid out of the first space, and the first gasket surrounds the third flow path.

[0009] In a cell unit according to one aspect of the present invention, the base material has a groove formed in the first surface that at least partially accommodates the first gasket.

[0010] In a cell unit according to one aspect of the present invention, the base material has a groove formed in the first surface that at least partially accommodates the second gasket.

[0011] In the cell unit according to one aspect of the present invention, the base material is formed from a resin material.

[0012] In a cell unit according to one aspect of the present invention, the membrane is an electrolyte membrane incorporated into a water electrolysis device or a fuel cell.

[0013] In the cell unit according to one aspect of the present invention, the first fluid is an electrolyte solution.

[0014] In a cell unit according to one aspect of the present invention, the second fluid is hydrogen. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a cell unit that has a simple design and can be used under high pressure. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view schematically illustrating the structure of a cell unit 2 incorporated in a water electrolysis apparatus 1 according to one specific example. [Figure 2] 1 is a cross-sectional view schematically illustrating the structure of a cell unit 2 incorporated in a water electrolysis apparatus 1 according to one specific example. [Figure 3] FIG. 1 is a plan view of the front surface 11 side of the cell unit 2 with one separator removed. [Figure 4] FIG. 10 is a plan view of the rear surface 12 side of the cell unit 2 with the other separator removed. [Figure 5] FIG. 4 is a plan view corresponding to FIG. 3 and schematically showing the anode side of the water electrolysis device 1 during use. [Figure 6] FIG. 5 is a plan view corresponding to FIG. 4 and schematically showing the cathode side of the water electrolysis apparatus 1 during use. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1 and 2 are cross-sectional views schematically showing the structure of a cell unit 2 incorporated in a water electrolysis apparatus 1 according to one specific example. FIG. 3 is a plan view of the front surface 11 side of the cell unit 2 with one separator removed. FIG. 4 is a plan view of the back surface 12 side of the cell unit 2 with the other separator removed. FIG. 1 is a cross-sectional view taken along line 1-1 in FIGS. 3 and 4. FIG. 2 is a cross-sectional view taken along line 2-2 in FIGS. 3 and 4. In FIGS. 1 and 2, the direction in which multiple cell units 2 are stacked is defined as stacking direction a.

[0018] A water electrolysis apparatus 1 according to one specific example includes a cell stack formed by stacking one or more cell units 2 shown in Figures 1 and 2 in a stacking direction a. The cell stack has current collector plates and insulating plates (neither of which is shown) stacked in the stacking direction a on the cell units 2 at both ends in the stacking direction a. With the current collector plates and insulating plates stacked at each end, the cell stack is fastened in the stacking direction a by a pair of end plates (not shown). The water electrolysis apparatus 1 is assembled in this manner.

[0019] The current collecting plates are formed, for example, from a gas-impermeable conductive material. Examples of conductive materials include copper plates. The current collecting plates are formed from a metal material. Examples of metal materials include titanium. Terminals are provided on each current collecting plate. Current is supplied to each cell unit 2 from these terminals through the current collecting plate. The insulating plates are formed from an insulating material. Examples of insulating materials include rubber and resin. The end plates are formed from a metal material. Note that, for example, a plurality of bolts extending in the stacking direction a and nuts threaded onto the bolts are used to fasten the end plates.

[0020] 1 to 4, a cell unit 2 according to one embodiment of the present invention includes a substrate 10 that extends in a predetermined shape along an imaginary plane perpendicular to the stacking direction a. In this example, as is clear from FIGS. 3 and 4, the substrate 10 is formed, for example, in a circular shape in plan view. The substrate 10 is formed, for example, from a resin material. Resin materials include, but are not limited to, general-purpose plastics (such as polypropylene (PP)), general-purpose engineering plastics (such as polycarbonate (PC)), and super engineering plastics (such as polyphenylene sulfide (PPS)).

[0021] The substrate 10 defines a first surface, i.e., a front surface 11, and a second surface, i.e., a back surface 12, which are opposed to each other. In this example, the front surface 11 and the back surface 12 are defined along an imaginary plane perpendicular to the stacking direction a. The substrate 10 has a through hole 13 that penetrates from the front surface 11 to the back surface 12 in the stacking direction a. The through hole 13 is formed, for example, in a circular shape in a plan view. The through hole 13 is formed, for example, from a large diameter portion 13a that opens on the front surface 11 side and a small diameter portion 13b that opens on the back surface side. The diameter of the small diameter portion 13b is defined to be smaller than the diameter of the large diameter portion 13a. A step surface 13c is formed within the through hole 13 based on the difference in diameter between the large diameter portion 13a and the small diameter portion 13b.

[0022] The step surface 13c extends in an annular shape along, for example, an imaginary plane perpendicular to the stacking direction a. The cell unit 2 includes a membrane assembly 20 supported by this step surface 13c. The membrane assembly 20 is formed, for example, in a circular shape in a plan view. An annular member 14 having an annular shape is disposed in the large diameter portion 13a. The annular member 14 sandwiches the outer edge of the membrane assembly 20 between itself and the step surface 13c. In this way, the membrane assembly 20 divides the through hole 13 into a first space 15 on the front surface 11 side and a second space 16 on the back surface 12 side. The annular member 14 is formed, for example, from the same resin material as the substrate 10. In this example, the diameter of the inner peripheral surface of the annular member 14 is set to be approximately equal to the diameter of the small diameter portion 13b.

[0023] The membrane assembly 20 includes an electrolyte membrane 21 and catalyst layers 22 and 23 formed on the front and back surfaces of the electrolyte membrane 21, respectively. The electrolyte membrane 21 is, for example, an ion exchange membrane, specifically, an anion exchange membrane (AEM). The catalyst layers 22 and 23 are formed from a metal material such as platinum or an alloy of platinum and other metals. Gas diffusion layers (GDL) 24 and 25 are formed on the surfaces of the catalyst layers 22 and 23, respectively. The gas diffusion layers 24 and 25 are, for example, porous transport layers (PTL). Materials for forming the gas diffusion layers 24 and 25 include, for example, carbon cloth and carbon paper.

[0024] As is clear from FIGS. 1 and 2, an annular recess, i.e., a groove 13d, is formed in the stepped surface 13c. A gasket 17 is disposed in this groove 13d. The gasket 17 is, for example, an O-ring. The gasket 17 is crushed toward the inside of the groove 13d when the annular member 14 is pressed against the stepped surface 13c. As a result, the gasket 17 seals the gap between the first space 15 and the second space 16. The gasket 17 is made of an elastic material. Examples of elastic materials include fluororubber (FKM), ethylene propylene diene rubber (EPDM), and silicone rubber (VMQ).

[0025] A flow path member 26 is disposed in the first space 15, while a flow path member 27 is disposed in the second space 16. The flow path members 26, 27 are formed, for example, from a metal material and are circular in plan view. Examples of metal materials include stainless steel and aluminum. Specifically, the flow path members 26, 27 are mesh-like expanded metals or the like. The substrate 10 is sandwiched between a pair of flat separators 30, 31. The flow path members 26, 27 allow fluid to flow through the first space 15 and the second space 16, respectively. The flow path member 25 is in contact with the gas diffusion layer 24 and the separator 30. The flow path member 26 is in contact with the gas diffusion layer 25 and the separator 31. In this way, the flow path members 26, 27 electrically connect the separators 30, 31 and the membrane assembly 20.

[0026] The separator 30 is in contact with the front surface 11 of the substrate 10. The separator 31 is in contact with the back surface 12 of the substrate 10. The substrate 10 is clamped in the stacking direction a by the separators 30, 31 through clamping by the pair of end plates described above. The separators 30, 31 are formed, for example, from a metal material. Examples of metal materials include stainless steel and titanium. Note that, for example, the separator 30 also serves as the separator 31 of the other cell unit 2 that is stacked on the front surface 11 side of the substrate 10 relative to this cell unit 2. Similarly, for example, the separator 31 also serves as the separator 30 of the other cell unit 2 that is stacked on the back surface 12 side of the substrate 10 relative to this cell unit 2.

[0027] In the cell unit 2, the electrolyte membrane 21 forms a membrane, the first space 15 is the anode (oxygen electrode) side, and the second space 16 is the cathode (hydrogen electrode) side. That is, the catalyst layer 22 arranged in the first space 15 constitutes the anode electrode, while the catalyst layer 23 arranged in the second space 16 constitutes the cathode electrode. The cell unit 2 is formed with a flow path (first flow path) 40 for introducing the electrolytic solution (first fluid) into the first space 15, a flow path (third flow path) 41 for guiding the electrolytic solution and oxygen from the first space 15, and a flow path (second flow path) 42 for guiding hydrogen (second fluid) from the second space 16.

[0028] The flow path 40 has a manifold 40a that penetrates the substrate 20, separator 30, and separator 31 in the stacking direction a, and a recess 40b formed on the surface 11 of the substrate 10 and the surface of the annular member 14 that is continuous with the surface 11. In this example, the manifold 40a is formed adjacent to one side of the first space 15 in a radial direction perpendicular to the stacking direction a. The recess 40b connects the manifold 40a and the first space 15. The recess 40b is covered by the separator 30. In this example, as is clear from FIG. 3 , the recess 40b is formed as a single groove that connects the manifold 40a and the first space 15, but as an alternative example, the recess 40b may be formed as a plurality of grooves.

[0029] The flow path 41 has a manifold 41a that penetrates the substrate 20, the separator 30, and the separator 31 in the stacking direction a, and a recess 41b formed in the surface 11 of the substrate 10. In this example, the manifold 41a is formed adjacent to one side of the first space 15 on the radially opposite side from the other side on which the manifold 40a is formed. The recess 41b connects the first space 15 and the manifold 41a. The recess 41b is covered by the separator 30. In this example, as is clear from FIG. 3, the recess 41b is formed as a single groove that connects the first space 15 and the manifold 40a, but as an alternative example, the recess 41b may be formed as a plurality of grooves.

[0030] The flow path 42 has a pair of manifolds 42a, 42a that penetrate the substrate 20, the separator 30, and the separator 31 in the stacking direction a, and a recess 42b formed in the rear surface 12 of the substrate 10. In this example, the pair of manifolds 42a, 42a are formed adjacent to the second space 16 on both sides of the second space 16 in the radial direction. One recess 42b communicates with one manifold 42a and the second space 16, and the other recess 42b communicates with the other manifold 42a and the second space 16. In this example, as is clear from FIG. 4, the recess 42b is formed as a single groove that communicates with the second space 16 and the manifold 42a, but as an alternative example, the recess 42b may be formed as a multiple-groove groove.

[0031] 3 and 4, the manifolds 40a, 41a of the flow paths 40, 41 are disposed at positions on opposite sides in the radial direction with the first space 15 and the second space 16 interposed therebetween, while the manifolds 42a, 42a of the flow path 42 are disposed at positions on opposite sides in the radial direction with the first space 15 and the second space 16 interposed therebetween. In this example, the manifolds 40a, 41a and the manifolds 42a, 42a are disposed at angular intervals of 90 degrees around the center point of the substrate 10 in a plan view. However, the manifolds 40a, 41a and the manifolds 42a, 42a may be disposed relative to each other at other angular intervals in a plan view.

[0032] A gasket (first gasket) 50 is disposed on the surface 11 of the substrate 10, surrounding the first space 15 and the flow paths 40 and 41 from the outside. In this example, the gasket 50 is formed in a generally elliptical shape in a plan view. The gasket 50 is formed, for example, from the same material as the gasket 17. The gasket 50 is at least partially disposed in an annular recess, i.e., a groove 10a, formed on the surface 11. That is, the groove 10a has a depth sufficient to accommodate at least a portion of the gasket 50 before elastic deformation. On the surface 11 of the substrate 10, the gasket 50 is crushed into the groove 10a by the separator 30. In this way, the gasket 50 seals the first space 15 and the flow paths 40 and 41.

[0033] Similarly, gaskets (second gaskets) 51, 51 are arranged on the surface 11 of the substrate 10, surrounding the flow paths 42, i.e., the pair of manifolds 42a, 42a, respectively. The gaskets 51, 51 are arranged outside the gasket 50. In this example, the gasket 51 is formed in a circular shape in a plan view. The gasket 51 is formed from, for example, the same material as the gaskets 17, 50. Each of the gaskets 51 is at least partially arranged in an annular recess, i.e., a groove 10b, formed on the surface 11. That is, the groove 10b has a depth sufficient to accommodate at least a portion of the gasket 51 before elastic deformation. On the surface 11 of the substrate 10, the gasket 51 is crushed into the groove 10b by the separator 30. In this way, the gasket 51 seals the flow paths 42.

[0034] Meanwhile, a gasket (third gasket) 52 is disposed on the rear surface 12 of the substrate 10, surrounding the second space 16 and the flow path 42 from the outside. In this example, the gasket 52 is formed in a generally elliptical shape in a plan view. The gasket 52 is formed from the same material as, for example, the gaskets 17, 50, and 51. The gasket 52 is at least partially disposed in an annular recess, i.e., a groove 10c, formed on the rear surface 12. That is, the groove 10c has a depth sufficient to accommodate at least a portion of the gasket 52 before elastic deformation. On the rear surface 12 of the substrate 10, the gasket 52 is crushed into the groove 10c by the separator 31. In this way, the gasket 52 seals the second space 16 and the flow path 42.

[0035] Similarly, gaskets (fourth gaskets) 53, 53 are arranged on the back surface 12 of the substrate 10, surrounding the flow paths 40, i.e., the manifolds 40a, 41a, respectively. The gaskets 53, 53 are arranged outside the gasket 52. In this example, the gasket 53 is formed in a circular shape in a plan view. The gasket 53 is formed from the same material as the gaskets 17, 50, 51, and 52, for example. Each of the gaskets 53 is at least partially arranged in an annular recess, i.e., a groove 10d, formed on the back surface 12. That is, the groove 10d has a depth sufficient to accommodate at least a portion of the gasket 53 before elastic deformation. On the back surface 12 of the substrate 10, the gasket 53 is crushed into the groove 10d by the separator 31. In this way, the gasket 53 seals the flow paths 40, 41.

[0036] Next, the use of the water electrolysis device 1 will be described below. In the water electrolysis device 1, an electrolyte solution is supplied to the first space 15 of each cell unit 2 via the flow path 40. The electrolyte solution is, for example, an alkaline solution with a pH of 14 or less. When a direct current is supplied to the current collector, a water electrolysis reaction occurs in each cell unit 2. Oxygen is produced on the anode side, i.e., the first space 15, and hydrogen is produced on the cathode side, i.e., the second space 16. Specifically, water in the electrolyte solution diffuses through the electrolyte membrane 21 and moves to the cathode side, where hydrogen (H2) and hydroxide ions (OH - ) is produced (H2O → H2 + 2OH - On the other hand, hydroxide ions move to the anode side through the electrolyte membrane 21. As a result, water (H2O) and oxygen (O2) are generated from the hydroxide ions on the anode side (2OH - →1 / 2O2+H2O+2e - Hydrogen produced on the cathode side is discharged from the cell unit 2 through a flow path 42. On the other hand, oxygen and water produced on the anode side are discharged from the cell unit 2 through a flow path 41.

[0037] FIG. 5 is a plan view corresponding to FIG. 3 and schematically illustrating the anode side of the water electrolysis device 1 during use. FIG. 6 is a plan view corresponding to FIG. 4 and schematically illustrating the cathode side of the water electrolysis device 1 during use. During use of the water electrolysis device 1, as shown in FIG. 5, on the anode side of each cell unit 2, the electrolyte solution is introduced from the manifold 40a through the recess 40b into the first space 15, and then from the recess 41b through the manifold 41a and discharged from the cell unit 2 together with oxygen. As shown by the arrows in FIG. 5, the electrolyte pressure P1 acts uniformly from the inside to the outside of the gasket 50. The electrolyte pressure P1 is typically set to less than 1 MPa.

[0038] As shown in FIG. 6, on the cathode side of each cell unit 2, hydrogen generated in the second space 16 is discharged from the manifolds 42a, 42a through the recesses 42b, 42b. A hydrogen pressure P2 acts uniformly on the gasket 52 from the inside to the outside, as shown by the arrows in FIG. 6. The hydrogen pressure P2 is usually set to be greater than the electrolyte pressure P1. Furthermore, on the outside of the gasket 52, the gaskets 53, 53 surrounding the manifolds 40a, 41a, respectively, are subjected to an electrolyte pressure P1 from the inside to the outside. On the other hand, on the anode side, on the outside of the gasket 50, the hydrogen pressure P2 acts from the inside to the outside on the gaskets 51, 51 surrounding the manifolds 42a, 42a, respectively.

[0039] In the water electrolysis apparatus 1 described above, the pressure acting on the gaskets 50 and 51 on the anode side of each cell unit 2 is unidirectional, from the inside to the outside. Similarly, the pressure acting on the gaskets 52 and 53 on the cathode side of each cell unit 2 is unidirectional, from the inside to the outside. In other words, no pressure acts on the gaskets 50 to 53 from the outside to the inside. As a result, even if the hydrogen pressure P2 is set to a high pressure, the gaskets 50 and 53 only need to be designed according to that pressure P2. This simplifies the design of the strength of the substrate 10 and other components constituting the cell unit 2 and the design of the gaskets 50 and 53. This allows the cell unit 2 to be used under high pressure with a simple design.

[0040] On the other hand, as a comparative example, for example, a case where gasket 50 surrounds gaskets 51, 51 on the anode side, or a case where gasket 52 surrounds gaskets 53, 53 on the cathode side, can be considered. In these comparative examples, for example, on the anode side, electrolytic solution pressure P1 acts on gasket 53 from the outside to the inside, while hydrogen pressure P2 acts on gasket 53 from the inside to the outside. In other words, pressure acts on gasket 51 from two different directions. Therefore, for example, when increasing the pressure P2 of the generated hydrogen, the strength design of substrate 10 and the like constituting cell unit 2 and the design of gasket 51 become complicated. The same can be said for the cathode side.

[0041] In the water electrolysis apparatus 1 described above, the gaskets 50 to 53 are all disposed in the grooves 10a to 10d formed in the front surface 11 or rear surface 12 of the substrate 10. However, any or all of the grooves 10a to 10d may be omitted. That is, the gaskets 50 to 53 may be, for example, adhered to the front surface 11 or rear surface 12 of the substrate 10. Furthermore, although the substrate 10 and membrane assembly 20 of each cell unit 2 are all formed to be circular in plan view, they may also be formed to be other polygonal shapes, such as rectangular, in plan view. Regarding the dimensions related to the water electrolysis apparatus 1, the substrate 10 may have a diameter of, for example, approximately 300 mm to 1000 mm. Furthermore, in the stacking direction a, each cell unit 2 may have a thickness of, for example, approximately 1 mm to 5 mm.

[0042] Furthermore, each cell unit 2 of the water electrolysis system 1 uses an anion exchange membrane (AEM) as the electrolyte membrane 21, but instead, a solid polymer electrolyte membrane such as a proton exchange membrane (PEM) may be used. In this case, pure water is supplied to the anode side of each cell unit 2. In the above-described embodiment, the cell unit 2 is incorporated into the water electrolysis system 1, but it may also be incorporated into a fuel cell.

[0043] Although the present invention has been described above through the above embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0044] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. Furthermore, the above-described embodiments do not limit the scope of application of the present invention, but may include any object to which the present invention can be applied. The components of the above-described embodiments, as well as their arrangement, materials, conditions, shape, size, etc., are not limited to those exemplified and can be modified as appropriate. For example, the present invention includes differences that arise during implementation due to manufacturing tolerances, etc. Furthermore, components shown in different embodiments can be partially substituted or combined with each other to the extent that they are not technically inconsistent. Furthermore, the various configurations can be selectively combined as appropriate to achieve at least some of the above-described problems and effects. [Explanation of symbols]

[0045] REFERENCE SIGNS LIST 1 water electrolysis device, 2 cell unit, 10 substrate, 10a, 10b, 10c, 10d groove, 11 surface (first surface), 12 back surface (second surface), 13 through-hole (hole), 13a large diameter portion, 13b small diameter portion, 13c stepped surface, 13d groove, 14 annular member, 15 first space, 16 second space, 17 gasket, 20 membrane assembly, 21 electrolyte membrane, 22, 23 catalyst layer, 24, 25 gas diffusion layer, 26 flow path member, 27 flow path member, 30, 31 separator, 40 flow path (first flow path), 40a manifold, 40b recess, 41 flow path (third flow path), 41a manifold, 41b recess, 42 flow path (second flow path), 42a manifold, 42b recess, 50 Gasket (first gasket), 51 gasket (second gasket), 52 gasket (third gasket), 53 gasket (fourth gasket), a stacking direction, P1 pressure, P2 pressure

Claims

1. a substrate defining a first surface and a second surface facing each other; a hole penetrating from the first surface to the second surface; a membrane disposed in the hole and dividing the hole into a first space on the first surface side and a second space on the second surface side; a first flow path formed in the base material for introducing a first fluid into the first space; a second flow path formed in the base material for leading out a second fluid from the second space; a first gasket disposed on the first surface and surrounding the first space and the first flow path; a second gasket disposed on the first surface and surrounding the second flow path outside the first gasket;

2. a third gasket disposed on the second surface and surrounding the second space and the second flow path; The cell unit according to claim 1 , further comprising: a fourth gasket disposed on the second surface and surrounding the first flow path outside the third gasket.

3. a third flow path formed in the base material for leading out the first fluid from the first space; The cell unit according to claim 1 or 2, wherein the first gasket surrounds the third flow path.

4. The cell unit according to claim 1 , wherein the base has a groove formed in the first surface that at least partially accommodates the first gasket.

5. The cell unit according to claim 1 , wherein the base has a groove formed in the first surface that at least partially accommodates the second gasket.

6. The cell unit according to claim 1 , wherein the base material is made of a resin material.

7. 2. The cell unit according to claim 1, wherein the membrane is an electrolyte membrane incorporated in a water electrolysis device or a fuel cell.

8. The cell unit according to claim 7 , wherein the first fluid is an electrolyte.

9. The cell unit of claim 8 , wherein the second fluid is hydrogen.

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