JP2018189300A - Electrochemical compressor and heat pump device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochemical compressor having high airtightness and high efficiency, and a heat pump device using the same.SOLUTION: An electrochemical compressor 104 comprises a fixing plate 114, a power supply plate 116, a separator 118, and an electrolyte membrane-electrode assembly 120. The separator 118 is made of metal. Thereby, because a pressure difference between the inside and outside of the compressor can be kept by improving airtightness of the separator 118, the electrochemical compressor having high efficiency and a heat pump device using the same can be realized.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electrochemical compressor and a heat pump apparatus using the same.

  In recent years, the demand for protection of the global environment has been increasing, and there is a strong demand for higher efficiency in air conditioners and other heat pump devices. Under such circumstances, a new compression method that replaces a normal mechanical compressor is being demanded, and as one of them, an electrochemical compressor using an electrolyte membrane used in a fuel cell has been proposed.

When an electrolyte membrane used in fuel cells gives a potential difference to this, H ₂ changes to protons (H ⁺ ) due to an ionization reaction in the catalyst layer, and moves from the higher potential side of the electrolyte membrane to the lower potential side. To do. At this time, the proton moves through the electrolyte membrane with a polar substance serving as a refrigerant such as water, alcohol, and ammonia. A technique for compressing the refrigerant gas of a polar substance using this phenomenon is called “electrochemical compression”, and a compressor using electrochemical compression is called “electrochemical compressor”. Compressor) ".

  The structure of the electrochemical compressor is similar to that of a stack used in a fuel cell, and is composed of at least a fixed plate, electrodes, a separator, and an electrolyte membrane / electrode assembly (Membrane Electrode Assembly).

  A separator, which is one of the components, has a function of suppressing gas leakage and has been proposed with improved airtightness (see, for example, Patent Document 1).

  FIG. 6 is a perspective view of a separator used in a conventional fuel cell described in Patent Document 1.

  As shown in FIG. 6, the separator 18 used in the conventional fuel cell has a diffusion channel 24 so that the reaction gas (hydrogen or oxygen) is in uniform contact with the electrolyte membrane / electrode assembly for high efficiency. Is provided.

  In addition, a graphite plate or the like is used for the separator 18 in consideration of cost and productivity, and the separator 18 is impregnated with a polymer material in order to prevent the reaction gas from leaking to the outside.

JP 2001-85032 A

  However, when an electrochemical compressor is configured using the fuel cell separator 18, the following problems occur. That is, the operating pressure range inside the electrochemical compressor is different from that of the fuel cell, and the inside of the compressor is below atmospheric pressure, so that a large pressure difference occurs between the inside and outside of the compressor. Therefore, it is difficult for the separator 18 to maintain the pressure difference between the inside and the outside of the compressor, and the efficiency is lowered.

FIG. 7 shows a gas inflow path diagram when a separator used in a conventional fuel cell is used in an electrochemical compressor. This electrochemical compressor has been proposed by the present applicant, and includes an electrolyte membrane / electrode assembly 20, a separator 18 disposed so as to be in contact with the electrolyte membrane / electrode assembly 20, and a separator 18 It is comprised from the electric power feeding board 16 arrange | positioned so that it may contact. Reference numeral 14 denotes a fixed plate.

  In the electrochemical compressor configured as described above, the separator material used in the conventional fuel cell has a large pressure difference between the inside and the outside of the compressor even when impregnated with a polymer material. Gas passes through the separator 18 and gas other than protons and refrigerant flows into the compressor from the outside. This inflow of gas makes it difficult to maintain the pressure difference between the inside and outside of the compressor, resulting in a reduction in efficiency.

  The present invention solves such a conventional problem, and by changing the material of the separator to a material having low gas permeability, an electrochemical compressor having high airtightness and high efficiency, and a heat pump apparatus using the same The purpose is to provide.

  In order to solve the conventional problems, the electrochemical compressor of the present invention and the heat pump apparatus using the same are made of a separator made of metal.

  Thereby, the airtightness of the separator can be improved, and the pressure difference between the inside and the outside of the compressor can be maintained.

  Since the electrochemical compressor of the present invention and the heat pump device using the same can maintain the pressure difference between the inside and the outside of the compressor, the efficiency can be improved.

The schematic diagram which shows the structure of the heat pump apparatus in embodiment of this invention. The schematic diagram which shows the structure of the electrochemical compressor in the same embodiment Configuration diagram of electrolyte membrane / electrode composite in the same embodiment External view of separator in the same embodiment Schematic diagram of working fluid and electron flow inside electrochemical compression in the same embodiment Perspective view of separator used in conventional fuel cell Gas inflow path diagram when separator used in conventional fuel cell is used in electrochemical compressor

  The first invention includes at least a fixed plate, a power feeding plate, a separator, and an electrolyte membrane / electrode assembly (MEA), wherein the separator is made of metal.

  Thereby, the airtightness of the separator can be improved and the pressure difference between the inside and the outside of the compressor can be maintained without impairing, so that the efficiency of the electrochemical compressor can be improved.

  In the second invention, in particular, the separator of the first invention is made of stainless steel. Thereby, since it becomes difficult to corrode a separator with water or an electric current, durability of an electrochemical compressor can be improved.

  In the third invention, in particular, the material of the separator of the first or second invention is SUS316.

  Thereby, since the corrosion resistance of a separator further improves, the durability of an electrochemical compressor can be further improved.

  4th invention is set as the structure which performed the gold plating process on the surface of the separator of any one of 1st to 3rd invention.

  Thereby, the conductivity of the separator is improved and the corrosion resistance is also improved, so that the efficiency of the electrochemical compressor can be improved and the durability can be improved.

  5th invention is a heat pump apparatus, This heat pump apparatus has a refrigerant circuit which connected the compressor, the condenser, the expansion mechanism, and the evaporator cyclically | annularly by piping, The said compressor is 1st to 4th. This is an electrochemical compressor according to any one of the inventions.

  Thereby, this heat pump apparatus can reduce the power consumption by the high efficiency which an electrochemical compressor has, and can implement | achieve energy saving.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a schematic diagram showing the configuration of the heat pump apparatus according to Embodiment 1 of the present invention.

  In FIG. 1, a heat pump apparatus 102 includes at least an electrochemical compressor 104 for compressing a refrigerant (not shown), a condenser 110 for condensing the refrigerant compressed by the electrochemical compressor 104, and the condensed refrigerant. An expansion mechanism 126 having a variable opening degree and an evaporator 108 for evaporating the expanded refrigerant are provided, and the electrochemical compressor 104, the condenser 110, the expansion mechanism 126, and the evaporator 108 are connected in a ring shape by piping. A refrigerant circuit 112 is configured.

  The refrigerant circuit 112 is filled with a refrigerant and a non-condensable gas (not shown) as working fluid. The refrigerant is a polar substance that is a condensable fluid, and water is used in the present embodiment. The non-condensable gas is an electrochemically active gas and is used for compressing the refrigerant in the refrigerant circuit 112, and hydrogen is used in the present embodiment.

  In the present invention, the term “electrochemically active gas” means ionization and ionization to polarize a substance in the electrolyte membrane from one surface with a relatively high potential to the other with a relatively low potential. A gas that has the ability to move to a surface.

  Next, the electrochemical compressor 104 will be described.

  FIG. 2 is a schematic diagram showing a configuration of an electrochemical compressor according to the embodiment.

  In FIG. 2, the electrochemical compressor 104 includes a stack 122 in which a plurality of cells 128 are stacked, and a fixing plate 114 that fixes the cells 128 so as to sandwich them.

  The cell 128 includes an electrolyte membrane / electrode assembly 120, a separator 118 disposed so as to be in contact with the electrolyte membrane / electrode assembly 120, and a power supply plate 116 disposed so as to be in contact with the separator 118. It consists of and.

  Here, the separator 118 is formed of SUS316, and the surface is further plated with gold.

  Next, the electrolyte membrane / electrode assembly 120 will be described.

  FIG. 3 is a configuration diagram of the electrolyte membrane / electrode assembly 120 in the same embodiment.

  In FIG. 3, the electrolyte membrane / electrode assembly 120 includes a first electrode 136 and a second electrode 138 arranged so as to sandwich an electrolyte membrane 134 made of a polymer material.

  Here, examples of the electrolyte membrane 134 include a perfluorosulfonic acid membrane such as Nafion (registered trademark of DuPont).

  Each of the first electrode 136 and the second electrode 138 includes a gas diffusion layer 140 made of a conductive base material such as carbon cloth, and a catalyst layer 142 made of a catalyst supported on the conductive base material.

  Note that a noble metal catalyst containing a noble metal may be used for the catalyst layer 142.

  Next, the configuration of the separator 118 will be described.

  FIG. 4 is an external view of the separator in the same embodiment.

  In FIG. 4, the separator 118 is provided with a diffusion channel 124 formed by a groove such as a serpentine shape so that the working fluid uniformly contacts the first electrode 136 of the electrolyte membrane / electrode assembly 120. Yes.

  About the electrochemical compressor comprised as mentioned above and the heat pump apparatus using the same, the operation | movement and an effect | action are demonstrated below.

  The working fluid composed of the refrigerant and the non-condensable gas that has absorbed the ambient heat by the evaporator 108 and flows into the electrochemical compressor 104 passes through the refrigerant circuit 112.

  Here, FIG. 5 shows a schematic diagram of the flow of working fluid and electrons inside the electrochemical compressor according to the embodiment.

In FIG. 5, the working fluid that has flowed into the electrochemical compressor 104 is uniformly brought into contact with the first electrode 136 of the electrolyte membrane / electrode assembly 120 through the diffusion flow path 124 provided in the separator 118. A voltage is applied between the first electrode 136 and the second electrode 138 so that the first electrode 136 becomes higher in potential. The hydrogen molecules (H ₂ ) of the non-condensable gas that is in contact with the catalyst layer 142 on the first electrode 136 side release electrons by an ionization reaction, ionize them into protons (H ⁺ ), and have polarity.

As a result, the proton (H ⁺ ) of the non-condensable gas is forcibly moved from the first electrode 136 to the second electrode 138 side in the electrolyte membrane 134 due to the potential difference. At that time, the water molecules (H ₂ O) of a plurality of refrigerants, which are polar substances, are moved together.

Then, the proton (H ⁺ ) of the non-condensable gas that has passed through the electrolyte membrane 134 receives electrons by the reaction opposite to the previous ionization reaction at the catalyst layer 142 on the second electrode 138 side, and from the proton (H ⁺ ) state. The state returns to the original hydrogen molecule (H ₂ ) state.

Water molecules (H ₂ O) of the refrigerant accompanied by one proton (H ⁺ ) of the non-condensable gas that is forcibly moved by the potential difference between the first electrode 136 and the second electrode 138 By moving a plurality of pieces from the electrode 136 side to the second electrode 138 side, the density of water molecules (H ₂ O) of the refrigerant is higher on the second electrode 138 side than on the first electrode 136 side. That is, a refrigerant compression phenomenon occurs across the electrolyte membrane / electrode assembly 120.

  Here, in this embodiment, water is used as the refrigerant, but the same effect can be obtained even if a natural refrigerant such as alcohol or ammonia is used as the refrigerant.

  The compressed refrigerant is cooled and condensed by the condenser 110, and then is decompressed by the expansion mechanism 126 and returns to the evaporator 108 again.

  Here, for example, cooling or the like is performed using an action of taking away ambient heat when the refrigerant evaporates in the evaporator 108.

  Further, when the refrigerant is condensed in the condenser 110, for example, heating or the like is performed using an action of radiating heat to the surroundings.

  Next, the function of the separator 118 constituting the electrochemical compressor 104 will be described.

  Since the separator 118 has a coolant channel 124 formed of, for example, a serpentine-shaped groove, the working fluid can be uniformly brought into contact with the electrolyte membrane / electrode assembly 120.

  In addition, since the separator 118 is a highly conductive material, electrons released by the ionization reaction described above can be efficiently guided to the other electrode.

  Here, if a substance other than the working fluid flows from the outside of the heat pump device 102 into the refrigerant circuit 112 in which the working fluid flows, it is difficult to maintain the pressure difference between the inside and the outside of the electrochemical compressor 104. Become. Therefore, the material constituting the heat pump device 102 is required to be a material with low gas permeability that can block the outside and the inside of the heat pump device 102. Therefore, the material forming the separator 118 is also required to have low gas permeability.

  In the electrochemical compressor 104 of the present embodiment, since the separator 118 is made of metal, the airtightness of the separator 118 can be improved, and the pressure difference between the inside and the outside of the electrochemical compressor 104 is maintained. be able to. As a result, the efficiency of the electrochemical compressor 104 can be increased.

  Furthermore, in this embodiment, since the separator 118 is made of stainless steel, the separator 118 is hardly corroded even when water or current flows, so that durability can be improved.

  Furthermore, in the present embodiment, by using SUS316 as the material of the separator 118, the corrosion resistance of the separator 118 is further improved, so that the durability can be improved.

  In this embodiment, SUS316 is used for the separator 118, but a stainless material having a different composition such as SUS316L or SUS304, or a metal material having high corrosion resistance such as a titanium alloy can also be used.

  In this embodiment, the surface of the separator 118 is subjected to gold plating, whereby the conductivity of the separator 118 is improved and the efficiency can be improved. Moreover, since corrosion resistance also improves, durability can also be improved.

  In the present embodiment, the fixing plate 114, the power feeding plate 116, and the separator 118 are each composed of independent components. However, if they have the same function, they need not be independent components.

  As described above, the present invention can provide an efficient compressor and a heat pump device using the same by maintaining the pressure difference between the inside and the outside of the electrochemical compressor. Therefore, it can be widely applied to not only an air conditioner but also a refrigeration heat pump apparatus such as a wine cellar.

104 Electrochemical Compressor 112 Refrigerant Circuit 114 Fixed Plate 116 Power Feed Plate 118 Separator 120 Electrolyte Membrane / Electrode Assembly

Claims (5)

An electrochemical compressor comprising at least a fixed plate, a power feeding plate, a separator, and an electrolyte membrane / electrode assembly (MEA), wherein the separator is made of metal. The electrochemical compressor according to claim 1, wherein the separator is made of stainless steel. The electrochemical compressor according to claim 1 or 2, wherein the separator is made of SUS316. The electrochemical compressor according to any one of claims 1 to 3, wherein a surface of the separator is subjected to gold plating. The heat pump apparatus which has the refrigerant circuit which connected the compressor, the condenser, the expansion mechanism, and the evaporator cyclically | annularly by piping, and made the said compressor the electrochemical compressor of any one of Claim 1 to 4.

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