JP6305878B2 - Microbial fuel cell - Google Patents

Description

  The present invention relates to a microbial fuel cell utilizing microbial metabolism.

  Conventionally, urban greening has been performed in which plants are planted on the rooftops and walls of buildings. In urban greening, a method of rooting a plant after placing a soil layer on a building, a method of artificially fixing a plant without using a soil layer, and the like are taken.

  The following are examples of merits of urban greening. One is that in the process of water retention and transpiration by plants (and soil layers), the building is cooled by heat of vaporization to suppress the temperature rise in the building, resulting in an energy saving effect. As a result, the city as a whole has the effect of suppressing the heat island phenomenon.

  In addition, there is an effect of reducing deterioration caused by exposure of the building to ultraviolet rays and wind and rain, and extending the life of the building. Furthermore, carbon dioxide is fixed in the process of photosynthesis by plants, which has the effect of purifying air and preventing global warming. In addition, plants can improve the landscape of buildings and cities.

  Here, natural energy-based power generation such as solar power generation is known as a technology having an ecological effect on buildings.

  On the other hand, microbial fuel cells that generate electricity by the action of microorganisms in soil and mud are known. Examples of documents disclosing microbial fuel cells include Japanese Unexamined Patent Application Publication No. 2007-32405 (Patent Document 1) and Japanese Unexamined Patent Application Publication No. 2013-84541 (Patent Document 2). Patent Document 1 discloses a biofuel cell using photosynthetic bacteria. Patent Document 2 discloses a microbial fuel cell using anaerobic microorganisms.

JP 2007-32005 A JP2013-84541A

  The inventors of the present invention have studied to provide a power generation system that can generate power by effectively using a greening surface as well as a greening structure. As the power generation system, since it is excellent in that it is clean, the use of the above-described solar power generation system or microbial fuel cell was examined.

  However, in the case of the photovoltaic power generation system and the microbial fuel cell described in Patent Document 1, light is required for power generation, and it has been difficult to effectively use a greening surface that similarly needs light. In addition, the microbial fuel cell described in Patent Document 2 is used by burying a battery cylinder in a sludge, and it is difficult to configure a greening surface, and it cannot be used as a greening structure. .

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a microbial fuel cell that is a greening structure and at the same time capable of generating power by effectively using a greening surface. .

  The microbial fuel cell of the present invention includes a microorganism-containing layer containing current-generating bacteria and organic matter, a negative electrode that is disposed in contact with the microorganism-containing layer and extracts electrons generated by decomposition of the organic matter by the current-generating bacteria, and an external environment containing oxygen On the other hand, it is provided with a positive electrode that is arranged so that oxygen in the external environment is in contact with it and donates electrons to oxygen, and a greening base layer that can grow plants in the external environment above.

In one embodiment of the present invention, the positive electrode also functions as the greening substrate layer.
In one Embodiment of this invention, the said greening base material layer is provided so that attachment or detachment is possible.

  In one Embodiment of this invention, the ion conductive film arrange | positioned between the said positive electrode and the said negative electrode is provided.

In the present invention, the microorganism-containing layer preferably contains soil.
In one embodiment of the invention, the plant is a moss plant.

  According to the present invention, it is possible to provide a microbial fuel cell that is a greening structure and at the same time can generate power by effectively using a greening surface.

It is sectional drawing which shows typically the structure of the microbial fuel cell of 1st Embodiment. It is sectional drawing which shows typically the structure of the microbial fuel cell of 2nd Embodiment. It is sectional drawing which shows typically the structure of the microbial fuel cell of 3rd Embodiment. It is sectional drawing which shows typically the structure of the microbial fuel cell of 4th Embodiment. It is sectional drawing which shows typically the structure of the microbial fuel cell of 5th Embodiment. It is sectional drawing which shows typically the system of 6th Embodiment using a microbial fuel cell. It is sectional drawing which shows typically the structure of the microbial fuel cell of 7th Embodiment. It is sectional drawing which shows typically the structure of the microbial fuel cell of 8th Embodiment.

  The microbial fuel cell of the present invention includes a microorganism-containing layer containing current-generating bacteria and organic matter, a negative electrode that is disposed in contact with the microorganism-containing layer and extracts electrons generated by the decomposition of organic matter by the current-generating bacteria, and oxygen Arranged so that oxygen in the external environment is in contact with the external environment, and includes a positive electrode that donates electrons to the oxygen, and a greening base layer that can grow plants in the external environment above. . Hereinafter, the microbial fuel cell of the present invention will be described more specifically by exemplifying embodiments. In the microbial fuel cell of each embodiment described in detail below, a negative electrode side soil layer is provided as a microorganism-containing layer.

[First Embodiment]
FIG. 1 is a cross-sectional view schematically showing the configuration of the microbial fuel cell of the first embodiment. A microbial fuel cell 11 shown in FIG. 1 has a housing 1 having an opening at the top, and is provided with a negative electrode portion 20 and a positive electrode portion 30 in order from the bottom of the housing 1. The positive electrode side soil layer 32 in the positive electrode part 30 also functions as a greening base material layer capable of growing the plant 61 in the upper external environment. The negative electrode part 20 and the positive electrode part 30 are provided in contact with each other, and are configured so that ions can move between them.

(Negative electrode part)
The negative electrode part 20 includes a negative electrode side soil layer 22 and a negative electrode 21 provided so as to be in contact therewith. In FIG. 1, the negative electrode 21 is provided above the negative electrode side soil layer 22, and the lower part is provided so as to be in contact with the negative electrode side soil layer 22. As long as the arrangement is in contact with the side soil layer 22, it may be provided inside the negative electrode side soil layer 22 or below the negative electrode side soil layer 22.

  The negative electrode side soil layer 22 is a soil containing current-generating bacteria and organic substances that can be metabolized by the current-generating bacteria, and may contain various nutrients as necessary. The negative electrode side soil layer 22 is, for example, humus. The water content of the negative electrode side soil layer 22 is not particularly limited, and may be in a mud state where the water content is large. Further, the negative electrode side soil layer 22 is not necessarily limited to soil, and is made of an aqueous solution containing current-generating bacteria and organic substances that can be metabolized by the current-generating bacteria, or an insulating material (eg, rock wool, absorbent cotton). It does not matter. In the negative electrode side soil layer 22, the next reaction (reaction R <b> 1) in which the current generating bacteria decompose organic substances is generated, and electrons are released, and the negative electrode 21 in contact with the negative electrode side soil layer 22 releases it through the negative electrode wiring 23. Electrons are taken out to the outside.

Organic substance + 2H ₂ O → CO ₂ + H ⁺ + e ⁻ (reaction R1)
Current-generating bacteria are bacteria that decompose organic substances such as sugar and acetic acid to release electrons, and examples include Shewanella bacteria. In the present embodiment, it is preferable that the oxygen concentration is low in the vicinity of the negative electrode 21. Therefore, the negative electrode side soil layer 22 is disposed below the positive electrode part 30 and is in a state in which oxygen is difficult to be supplied. It is preferable that it is a sex bacteria.

  The negative electrode 21 is preferably formed of a carbon material having high corrosion resistance. For example, a carbon felt or a material obtained by coating a metal substrate with carbon can be used. As the metal base material, it is preferable to use a mesh-like material made of SUS and having a large surface area. Examples of the carbon coating method include carbon plating with molten salt, non-woven fabric spraying, carbon-containing coating, sputtering, and the like.

  The negative electrode wiring 23 is preferably made of SUS or the like having high corrosion resistance, and may be further covered with an insulating resin or the like.

(Positive part)
The positive electrode part 30 includes a positive electrode side soil layer 32 and a positive electrode 31 provided so as to be in contact therewith. In FIG. 1, the positive electrode 31 is provided above the positive electrode-side soil layer 32 and the lower part is provided so as to be in contact with the positive electrode-side soil layer 32, but is not limited to such an arrangement. As long as the arrangement is not in contact with the side soil layer 32, energization with the negative electrode 21, and does not prevent the positive electrode side soil layer 32 from functioning as a greening base material layer, it may be provided inside the positive electrode side soil layer 32. Although it may be provided below the positive electrode side soil layer 32, the positive electrode 31 is preferably provided above the positive electrode side soil layer 32, that is, on the opening side, because it is preferably disposed in a place with a high oxygen concentration. .

In this embodiment, since the positive electrode side soil layer 32 functions also as the greening base material layer 62, it consists of the greening base material which can grow the plant 61. FIG. The positive soil layer 32 can take in oxygen and water supplied to the plant 61. The greening base material used here consists of soil, peat, etc., for example, and may contain various fertilizers as needed. Moreover, the positive electrode side soil layer 32 is not necessarily limited to soil, and may be an aqueous solution containing oxygen and nutrients of the plant 61 or an insulating material (eg, rock wool, absorbent cotton) containing the aqueous solution. In the positive electrode side soil layer 32, electrons are donated to oxygen from the positive electrode 31 in contact with the positive electrode side soil layer 32, and the following reaction (reaction R2) which is a reduction reaction of oxygen occurs. Hydrogen ions (H ⁺ ) generated in the reaction R1 in the negative electrode side soil layer 22 move to the positive electrode side soil layer 32 and are utilized as hydrogen ions (H ⁺ ) in the reaction R2.

O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O (reaction R2)
The positive electrode 31 is preferably a material having oxygen reducing ability or a material coated with them. For example, in addition to platinum, gold, carbon, etc., carbon modified with a platinum catalyst, carbon modified with an enzyme catalyst having oxygen reducing ability, carbon modified with a microorganism, and the like can be used. In consideration of cost and simplicity of production, it is preferably formed of a carbon material having high corrosion resistance. For example, a carbon felt or a material obtained by coating a metal substrate with carbon can be used. As the metal base material, it is preferable to use a mesh-like material made of SUS and having a large surface area. Examples of the carbon coating method include carbon plating with molten salt, non-woven fabric spraying, carbon-containing coating, sputtering, and the like.

  The positive electrode 31 has a plurality of through holes through which the plant 61 can penetrate so as not to prevent the plant 61 from growing upward. Moreover, since the positive electrode 31 has a through-hole, the positive electrode-side soil layer 32 can easily take in oxygen and water in the upper external environment and oxygen and water supplied to the plant 61.

  The positive electrode wiring 33 is preferably made of SUS or the like having high corrosion resistance, and may be further covered with an insulating resin or the like.

(Greening base layer)
In the present embodiment, the greening base material layer 62 serves as the positive soil layer 32 as described above. The greening base material layer 62 is configured such that the plant 61 can grow in the upper external environment. The plant 61 may be vegetated while growing on the greening base layer 62, or may be grown from the seed using a greening base including the seeds of the plant 61. The kind of the plant 61 is not limited, and various plants such as algae, moss, gramineous plant, and leguminous plant can be used. In addition, since moss can be vegetated with little soil, it is preferable from the point that the quantity of the soil of the greening base material layer 62 can be reduced.

(Casing)
The housing 1 is made of at least an insulator or a material subjected to insulation treatment that prevents the negative electrode 21 and the positive electrode 31 from being energized.

(Use / Effect)
In the microbial fuel cell of the present embodiment, an electromotive force is generated between the negative electrode wiring 23 and the positive electrode wiring 33 due to the reaction R1 and the reaction R2. The electromotive force generated by the microbial fuel cell of the present embodiment can be used not only as a power source for operating the electric appliance, but also by monitoring the magnitude of the generated electromotive force, the state of the greening substrate layer 62 ( For example, it is possible to detect wetness and nutrients).

Since the microbial fuel cell of this embodiment is provided with the greening base material layer 62, it can be used for rooftop greening and wall surface greening. Moreover, since the greening base material layer 62 also serves as the positive electrode side soil layer 32, ion movement occurs. Therefore, the growth of the plant 61 can be adjusted by controlling the movement of ions in the greening substrate layer 62.

  Furthermore, in the microbial fuel cell of this embodiment, the positive electrode 31 can use oxygen in the external environment or oxygen supplied to the plant 61 for the reaction R2, so that the frequency of maintenance of the positive electrode side soil layer 32 is reduced. can do.

[Second Embodiment]
FIG. 2 is a cross-sectional view schematically showing the configuration of the microbial fuel cell according to the second embodiment. A microbial fuel cell 12 shown in FIG. 2 has a housing 1 having an opening on the upper side, and is provided with a negative electrode portion 20 and a positive electrode portion 30 in order from the lower side of the housing 1. The positive electrode side soil layer 32 in the positive electrode part 30 functions as a greening base material layer capable of growing the plant 61 in the upper external environment. The negative electrode part 20 and the positive electrode part 30 are provided via the ion conductive film 4, and are configured so that ions can move between the two.

  The configuration of the microbial fuel cell of the present embodiment is different from that of the first embodiment in that the ion conductive film 4 is provided between the negative electrode portion 20 and the positive electrode portion 30, and in the negative electrode portion 20, the negative electrode 21 Is different only in that it is provided inside the negative electrode side soil layer 22. Only elements that are different from the first embodiment will be described below.

(Ion conductive membrane)
The ion conductive film 4 is a film having ion conductivity. Accordingly, hydrogen ions (H ⁺ ) generated in the reaction R1 in the negative electrode part 20 pass through the ion conductive film 4 and move to the positive electrode part 30, and are used as hydrogen ions (H ⁺ ) in the reaction R2 in the positive electrode part. Moreover, since the ion conductive film 4 can suppress or block the movement of oxygen from the positive electrode portion 30 to the negative electrode portion 20, the reaction R1 when using an anaerobic bacterium that generates current is more efficiently performed. Can proceed.

  The ion conductive film 4 can be formed, for example, by mixing agar salt with potassium chloride or sodium chloride. The ion conductive membrane 4 may be a commercially available Nafion (registered trademark, manufactured by DuPont) or the like. An oxygen absorber may be further added to the ion conductive film 4. As the oxygen absorber, for example, an organic substance having an oxygen reducing ability, an inorganic substance having an oxygen adsorptivity, or the like can be used. The ion conductive film 4 is provided between the positive electrode part 30 and the negative electrode part 20. In FIG. 1, the ion conductive film 4 is provided in contact with the positive electrode side soil layer 32 on the upper surface and in contact with the negative electrode side soil layer 22 on the lower surface. Yes. Depending on the configuration of the positive electrode part 30 and the negative electrode part 20, the ion conductive film 4 may be in direct contact with the positive electrode 31 or the negative electrode 21.

(Use / Effect)
In the microbial fuel cell of the present embodiment, an electromotive force is generated between the negative electrode wiring 23 and the positive electrode wiring 33 due to the reaction R1 and the reaction R2. The electromotive force generated by the fuel cell of the present embodiment can be used not only as a power source for operating the electric appliances, but also by monitoring the magnitude of the generated electromotive force, the state of the greening substrate layer 62 (for example, , Wetness, nutrients) can also be detected.

Since the microbial fuel cell of this embodiment is provided with the greening base material layer 62, it can be used for rooftop greening and wall surface greening. Moreover, since the greening base material layer 62 also serves as the positive electrode side soil layer 32, ion movement occurs. Therefore, the growth of the plant 61 can be adjusted by controlling the movement of ions in the greening substrate layer 62.

  The microbial fuel cell of the present embodiment can improve the amount of power generation by using the ion conductive membrane 4, and can be made thin when obtaining the same amount of power generation. Therefore, the microbial fuel cell can be configured to be lighter and is useful when used for rooftop greening and wall surface greening.

  Furthermore, in the microbial fuel cell of this embodiment, the positive electrode 31 can use oxygen in the external environment or oxygen supplied to the plant 61 for the reaction R2, so that the frequency of maintenance of the positive electrode side soil layer 32 is reduced. can do.

[Third Embodiment]
FIG. 3 is a cross-sectional view schematically showing the configuration of the microbial fuel cell according to the third embodiment. A microbial fuel cell 13 shown in FIG. 3 has a housing 1 having an opening on the upper side, and is provided with a negative electrode portion 20 and a positive electrode portion 30 in order from the lower side of the housing 1. And the greening base material layer 62 is further provided in the upper part of the opening part of the housing | casing 1 so that removal is possible. The negative electrode part 20 and the positive electrode part 30 are provided in contact with each other, and are configured so that ions can move between them. In addition, between the negative electrode part 20 and the positive electrode part 30, the ion conductive film as provided in 2nd Embodiment can also be provided. By providing the ion conductive membrane, the amount of power generation can be improved.

  The microbial fuel cell of the present embodiment is different from the configuration of the first embodiment in that a greening base material layer 62 is provided above the opening of the housing 1 separately from the positive electrode 30, and the positive electrode of the positive electrode 30. The only difference is that the side soil layer 32 is not configured to double as the greening base material layer 62. The positive electrode 31 is configured to have a plurality of through-holes as in the first embodiment, and the positive electrode-side soil layer 32 includes oxygen and water in the upper external environment, and the upper greening base material layer. It becomes easy to take in oxygen and water supplied to the plant 61 vegetated in 62. Only elements that are different from the first embodiment will be described below.

(Greening base layer)
The greening base material layer 62 is as described in the first embodiment except that it does not serve as the positive electrode side soil layer 32 and is detachably provided above the opening of the housing 1.

(Use / Effect)
In the microbial fuel cell of the present embodiment, an electromotive force is generated between the negative electrode wiring 23 and the positive electrode wiring 33 due to the reaction R1 and the reaction R2. The electromotive force generated by the fuel cell of the present embodiment can be used as a power source for operating the electric appliance.

  Since the microbial fuel cell of this embodiment is provided with the greening base material layer 62, it can be used for rooftop greening and wall surface greening. Since the greening base material layer 62 can be easily removed, the plant 61 can be easily exchanged according to the state, season, etc. of the plant 61.

  Furthermore, in the microbial fuel cell of this embodiment, the positive electrode 31 can use oxygen in the external environment or oxygen supplied to the plant 61 for the reaction R2, so that the frequency of maintenance of the positive electrode side soil layer 32 is reduced. can do.

[Fourth Embodiment]
FIG. 4 is a cross-sectional view schematically showing the configuration of the microbial fuel cell of the fourth embodiment. The microbial fuel cell 14 shown in FIG. 4 has a housing 1 having an opening on the upper side, and is provided with a negative electrode portion 20 and a positive electrode side soil layer 32 of a positive electrode portion 30 in order from the lower portion of the housing 1. And the positive electrode 31 of the positive electrode part 30 is further provided above the opening part of the housing | casing 1 so that removal is possible. The positive electrode 31 also functions as a greening base layer capable of growing the plant 61 in the upper external environment. The negative electrode part 20 and the positive electrode part 30 are provided in contact with each other, and are configured so that ions can move between them. In addition, between the negative electrode part 20 and the positive electrode part 30, the ion conductive film as provided in 2nd Embodiment can also be provided. By providing the ion conductive membrane, the amount of power generation can be improved.

  The configuration of the microbial fuel cell of the present embodiment is different from that of the first embodiment in that the positive electrode 31 serves as the greening base material layer 62 instead of the positive electrode side soil layer 32 of the positive electrode part 30. Is different in that it is detachably provided above the opening of the housing 1. Only elements that are different from the first embodiment will be described below.

(Positive electrode)
The positive electrode 31 is not limited as long as the positive electrode 31 includes a conductive material and a greening base material and can be removed. For example, the structure provided with the carbon-coated mesh-like metal base material and the greening base material in a metal base material, and these are hold | maintained integrally so that removal is possible is mentioned. The greening base material and the plant 61 are as described in the first embodiment.

(Use / Effect)
In the microbial fuel cell of the present embodiment, an electromotive force is generated between the negative electrode wiring 23 and the positive electrode wiring 33 due to the reaction R1 and the reaction R2. The electromotive force generated by the fuel cell of the present embodiment can be used as a power source for operating the electric appliance.

  Since the microbial fuel cell of this embodiment is provided with the greening base material layer 62, it can be used for rooftop greening and wall surface greening. Since the positive electrode 31 that also serves as the greening base layer 62 can be easily removed, the plant 61 can be easily replaced in accordance with the state, season, etc. of the plant 61.

  Furthermore, in the microbial fuel cell of this embodiment, the positive electrode 31 can use oxygen in the external environment or oxygen supplied to the plant 61 for the reaction R2, so that the frequency of maintenance of the positive electrode side soil layer 32 is reduced. can do.

[Fifth Embodiment]
FIG. 5 is a cross-sectional view schematically showing the configuration of the microbial fuel cell of the fifth embodiment. A microbial fuel cell 15 shown in FIG. 5 includes a housing 1 having an opening on the upper side, and is provided with a negative electrode portion 20 and a positive electrode side soil layer 32 of a positive electrode portion 30 in order from the lower portion of the housing 1. The positive electrode side soil layer 32 in the positive electrode part 30 also functions as a greening base material layer capable of growing the plant 61 in the upper external environment. The negative electrode part 20 and the positive electrode part 30 are provided in contact with each other, and are configured so that ions can move between them. In addition, between the negative electrode part 20 and the positive electrode part 30, the ion conductive film as provided in 2nd Embodiment can also be provided. By providing the ion conductive membrane, the amount of power generation can be improved.

  The microbial fuel cell of this embodiment is different from the configuration of the first embodiment only in that a plurality of through holes are provided on the bottom surface of the housing 1. The microbial fuel cell of the present embodiment can be used by being embedded in the soil layer 71. When used in this manner, the microbial fuel cell is decomposed from the soil layer 71, which is an external environment, to the negative electrode side soil layer 22 and decomposed. The target organic matter is continuously supplied.

(Use / Effect)
In the microbial fuel cell of the present embodiment, an electromotive force is generated between the negative electrode wiring 23 and the positive electrode wiring 33 due to the reaction R1 and the reaction R2. The electromotive force generated by the fuel cell of the present embodiment can be used as a power source for operating the electric appliance.

  The microbial fuel cell of the present embodiment includes the greening base layer 62 and can be used by being embedded in the soil layer 71. Therefore, the microbial fuel cell can be used for greening of large-scale land such as farmland and ground. . In addition, since the current generating bacteria and the organic matter to be decomposed are continuously supplied from the soil layer 71 which is the external environment to the negative electrode side soil layer 22, the reaction R1 in the negative electrode part 20 is likely to occur stably and stably for a long time. It is possible to generate electric power.

  Furthermore, in the microbial fuel cell of this embodiment, the positive electrode 31 can use oxygen in the external environment or oxygen supplied to the plant 61 for the reaction R2, so that the frequency of maintenance of the positive electrode side soil layer 32 is reduced. can do.

[Sixth Embodiment]
FIG. 6 is a cross-sectional view schematically showing a system of a sixth embodiment using a microbial fuel cell. The system shown in FIG. 6 is configured using the microbial fuel cell 11 of the first embodiment.

  In the system of the present embodiment, in addition to the microbial fuel cell 11, a control circuit 81 that performs control by an electromotive force obtained between the negative electrode wiring 23 and the positive electrode wiring 33, and a water storage tank 82 in which water is stored in advance. A water injection pipe 84 connected to the water storage tank 82, and an electromagnetic valve 83 that opens and closes between the water storage tank 82 and the water injection pipe 84.

  The electric energy obtained between the negative electrode wiring 23 and the positive electrode wiring 33 is used by the control circuit 81 to open and close the electromagnetic valve 83 at a predetermined timing. When the electromagnetic valve 83 is opened, the water in the water storage tank 82 flows into the water injection pipe 84 due to water pressure, and water is dripped onto the plant 61 from the water injection port 85 provided in the water injection pipe 84. The electromagnetic valve 83 is closed again by electrical energy obtained between the negative electrode wiring 23 and the positive electrode wiring 33 at a predetermined timing.

  According to this embodiment, since it can be set as the system which can supply water to the plant 61 automatically, the maintenance of the plant 61 becomes easy. The control circuit 81 preferably has a function of storing electric power so that electric power can be used in addition to opening and closing of the electromagnetic valve 83. As the water in the water storage tank 82, for example, stored rainwater may be used, or tap water may be used. A pump may be used instead of the electromagnetic valve 83.

  Although the system is configured using the first microbial fuel cell 11 in FIG. 6, the system can be configured in the same manner using the microbial fuel cells of the second to fifth embodiments. The application of the first to fifth microbial fuel cells is not limited to these, and various devices can be used as a load. For example, by turning on the LED with the obtained electric power, it can be used as illumination or electrical decoration of a greening place. Moreover, the electric power obtained by the microbial fuel cell can also be used as a power source for various sensors. For example, a human sensor can be provided at a greening site for crime prevention.

[Seventh Embodiment]
FIG. 7 is a cross-sectional view schematically showing the configuration of the microbial fuel cell according to the seventh embodiment. A microbial fuel cell 16 shown in FIG. 7 has a housing 1 having an opening on the upper side, and is provided with a positive electrode portion 30 and a negative electrode portion 20 in order from the bottom of the housing 1. The negative electrode side soil layer 22 in the negative electrode part 20 functions as a greening base material layer capable of growing the plant 61 in the upper external environment. The negative electrode part 20 and the positive electrode part 30 are provided in contact with each other, and are configured so that ions can move between them. In addition, between the negative electrode part 20 and the positive electrode part 30, the ion conductive film as provided in 2nd Embodiment can also be provided. By providing the ion conductive membrane, the amount of power generation can be improved. Further, when the ion conductive film is used, the positive electrode side soil layer 32 can be omitted.

  The configuration of the microbial fuel cell of the present embodiment is different from that of the first embodiment in that a plurality of through holes are provided in the bottom surface of the housing 1, a positive electrode 31 is disposed on the bottom surface, and a greening group. The difference is that the material layer 62 is the negative electrode side soil layer 22.

(Use / Effect)
In the microbial fuel cell of the present embodiment, an electromotive force is generated between the negative electrode wiring 23 and the positive electrode wiring 33 due to the reaction R1 and the reaction R2. The electromotive force generated by the fuel cell of the present embodiment can be used as a power source for operating the electric appliance.

  The microbial fuel cell according to the present embodiment is characterized in that since the positive electrode 31 is not disposed on the greening base material layer 62, the greening base material layer 62 is easily maintained despite the integrated structure. Further, even when maintenance of the greening base material layer 62 is performed, since it is not necessary to disassemble the positive electrode 31 and the negative electrode 21, stable power generation is possible before and after the maintenance. Furthermore, since a plurality of through holes are provided on the bottom surface of the housing 1, it is possible to discharge excess moisture given to the plant.

  Since the microbial fuel cell of the present embodiment can have a structure similar to that of a general flower pot, using the power obtained by the microbial fuel cell, lighting of LEDs, sensing of the state of plants and soil, It is possible to provide a flower pot capable of driving an automatic water supply system as shown in the sixth embodiment.

[Eighth Embodiment]
FIG. 8 is a cross-sectional view schematically showing the configuration of the microbial fuel cell according to the eighth embodiment. The microbial fuel cell 17 shown in FIG. 8 has a housing 1 having an opening at the top, and in order from the bottom of the housing 1, a positive electrode 31, a positive soil layer 32 that also serves as a negative soil layer 22, a negative electrode 21, and a positive electrode side. A negative electrode-side soil layer 22 that also serves as the soil layer 32 and a positive electrode 31 are provided. The negative electrode side soil layer 22 on the resurface functions as a greening base layer 62 capable of growing the plant 61 in the upper external environment. Here greening substrate layer, to may be independently on the positive electrode 31 as shown in the third embodiment, itself cathode 31 as shown in the fourth embodiment have a greening base layer It doesn't matter. The negative electrode part 20 and the positive electrode part 30 are provided in contact with each other, and are configured so that ions can move between them. In addition, between the negative electrode part 20 and the positive electrode part 30, the ion conductive film as provided in 2nd Embodiment can also be provided. By providing the ion conductive membrane, the amount of power generation can be improved.

  The microbial fuel cell of this embodiment is different from the configuration of the seventh embodiment in that the positive electrode 31 is also arranged on the upper surface.

(Use / Effect)
In the microbial fuel cell of the present embodiment, an electromotive force is generated between the negative electrode wiring 23 and the positive electrode wiring 33 due to the reaction R1 and the reaction R2. The electromotive force generated by the fuel cell of the present embodiment can be used as a power source for operating the electric appliance.

  In the microbial fuel cell of the present embodiment, the positive electrode 31 is disposed on the bottom surface and the top surface of the housing, so that the electrode area of the positive electrode can be increased and the power generation amount of the microbial fuel cell can be increased. Furthermore, since a plurality of through holes are provided on the bottom surface of the housing 1, it is possible to discharge excess moisture given to the plant.

  Since the microbial fuel cell of the present embodiment can have a structure similar to that of a general flower pot, using the power obtained by the microbial fuel cell, lighting of LEDs, sensing of the state of plants and soil, It is possible to provide a flower pot capable of driving an automatic water supply system as shown in the sixth embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Case, 4 Ion conductive membrane, 11, 12, 13, 14, 15, 16, 17 Microbial fuel cell, 20 Negative electrode part, 21 Negative electrode, 22 Negative electrode side soil layer, 23 Negative electrode wiring, 30 Positive electrode part, 31 Positive electrode, 32 Positive electrode side soil layer, 33 Positive electrode wiring, 61 Plant, 62 Greening base material layer, 71 Soil layer, 81 Control circuit, 82 Water storage tank, 83 Solenoid valve, 84 Water injection pipe.

Claims (6)

A microorganism-containing layer containing current generating bacteria and organic matter;
A negative electrode that is disposed in contact with the microorganism-containing layer and extracts electrons generated by the decomposition of the organic matter by the current-generating bacteria;
A positive electrode that is arranged so that oxygen in the external environment is in contact with an external environment containing oxygen, and donates electrons to oxygen;
With a greening base material layer capable of growing plants in the upper external environment,
The greening base layer is detachably provided,
Microbial fuel cell. The microbial fuel cell according to claim 1 , comprising an ion conductive membrane disposed between the positive electrode and the negative electrode. A microorganism-containing layer containing current generating bacteria and organic matter;
A negative electrode that is disposed in contact with the microorganism-containing layer and extracts electrons generated by the decomposition of the organic matter by the current-generating bacteria;
A positive electrode that is arranged so that oxygen in the external environment is in contact with an external environment containing oxygen, and donates electrons to oxygen;
A greening substrate layer capable of growing plants in the upper external environment;
A microbial fuel cell comprising an ion conductive membrane disposed between the positive electrode and the negative electrode. The microbial fuel cell according to claim 1, wherein the positive electrode is also the greening base material layer.   The microbial fuel cell according to claim 1, wherein the microorganism-containing layer includes soil.   The microbial fuel cell according to claim 1, wherein the plant is a moss plant.

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