Photovoltaic devices made from renewable biomaterials

Abstract

[Solution] A photovoltaic device made of renewable biomaterial, comprising a carrier, one or more microalgae cells, a cathode, a permeable separator, and an electrolyte solution, wherein the carrier comprises a plurality of conductive sheets extending in a planar direction, these conductive sheets being electrically connected to each other, the microalgae cells being provided on the carrier, the permeable separator being provided between the carrier and the cathode, the electrolyte solution being usable as a culture medium for algae and in contact with the cathode and microalgae cells, each conductive sheet having a first surface area for providing microalgae cells and in contact with the electrolyte solution, the cathode having a second surface area in contact with the electrolyte solution, and the microalgae cells becoming anodes by capturing sunlight in the electrolyte solution and growing as a microalgae layer on these conductive sheets.

Description

Technical Field

[0001] The present invention relates to a photovoltaic device, and particularly to a photovoltaic device manufactured from renewable biomaterials.

Background Art

[0002] Most conventional photovoltaic devices (also called solar cells) employ semiconductor materials, among which silicon is the main one, and other materials include GaAs, GaAlAs, InP, CdS, CdTe, etc.

[0003] As the demand for renewable energy increases, the amount of semiconductor materials or compound materials used in conventional photovoltaic devices is also increasing. Problems such as energy consumption, environmental pollution, and high costs generated during the production and recovery of these materials have also been taken up, discussed, and criticized. In particular, in the case of a photovoltaic device with high power generation efficiency, higher purity materials are required, so the above-mentioned problems have become more prominent.

[0004] Recently, bio-photovoltaic devices have been proposed, and as a technology for producing photovoltaic devices in a cleaner and more energy-saving manner, for example, there are Patent Documents 1 to 3, etc. However, conventional bio-photovoltaic devices have problems with poor power generation efficiency, so there is room for improvement.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0006] The present invention comprises a carrier, one or more microalgae cells, a cathode, a permeable separator, and an electrolyte solution, wherein the carrier comprises a plurality of conductive sheets extending in a planar direction, these conductive sheets being electrically connected to one another, the microalgae cells being provided on the carrier, the microalgae cells being of the genera Spirulina, Anabaena, Oschilatoria, Chlorella, Chlorococcum, or a combination thereof, the cathode comprising a conductive material, the permeable separator being provided between the carrier and the cathode, and the electrolyte solution being used as a culture medium for the algae. The present invention provides a photovoltaic device made of renewable biomaterials, wherein the electrolyte solution is in contact with the cathode and the microalgae cells, each conductive sheet has a first surface area on which the microalgae cells are placed and which is in contact with the electrolyte solution, the cathode has a second surface area in contact with the electrolyte solution, the ratio of the sum of the first surface areas of these conductive sheets to the second surface area of ​​the cathode is 32 to 64, and the microalgae cells capture sunlight in the electrolyte solution and grow as a microalgae layer on these conductive sheets to become the anode. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic diagram of a photovoltaic device according to one embodiment of the present invention. [Figure 2] A schematic diagram of a photovoltaic device in an experimental example of the present invention. [Figure 3] This is a photograph of a photovoltaic device, an experimental example of the present invention. [Figure 4] Figure 3 is a graph showing the voltage and current data for the experimental example. [Figure 5] This is a photograph from the second week of the experiment shown in Figure 3. [Figure 6] This is a photograph of a group of photovoltaic devices used in an experimental example of the present invention. [Figure 7] Figure 6 is a graph showing the voltage and current data for the experimental example. [Figure 8] Figure 6 is a photograph of the LED light bulb lit up in the experimental example. [Figure 9]This graph shows voltage and current data when different microalgae cells are used in the experimental examples of the present invention. [Modes for carrying out the invention]

[0008] In this specification and the claims, terms such as "first," "second," etc., are used when describing certain elements or features, but these terms are not used to limit these elements or features. They are used only to distinguish one element or feature from another. For example, a first element or feature can be described as a second element or feature, and similarly, a second element or feature can be described as a first element or feature.

[0009] When we say that an element is "located on top of," "covering," or "located above" another element, it may be directly located on top of that element, directly covering it, directly located above it, or interposed by another element. Conversely, when we say that an element is "directly located on top of," "directly covering," or "directly located above" another element, there is no intermediate element.

[0010] The terms used in this specification and in the claims are used only to describe specific examples and are not intended to be limiting. Unless otherwise explicitly stated in the context, or unless the number of elements is intentionally limited, the singular forms “one” and “the said” as used herein also include the plural forms. Furthermore, it should be understood that, as used herein, the terms “include” and / or “inclusion” indicate the presence of the described features, elements and / or components, but do not exclude the addition or presence of one or more other features, elements, components and / or groups thereof. The indefinite and definite articles include both singular and plural forms unless the context suggests otherwise.

[0011] Unless otherwise specified, all numerical values ​​relating to size, number, and physical properties described herein and in the claims should be understood to be modified in all cases with the term “approximately.” Therefore, unless otherwise stated, all numerical parameters described herein and in the claims are approximations, and a person skilled in the art can modify these approximations as appropriate to obtain desired properties using the information disclosed herein and in the claims. Where numerical ranges are given at endpoints, this includes all numerical values ​​within that range and any range within that range; for example, 1 to 5 includes numerical values ​​such as 1, 1.2, 1.5, 1.7, 2, 2.75, 3, 3.80, 4, and 5.

[0012] The present invention discloses a photovoltaic device made from renewable biomaterials, referring to Figure 1, in one example, the photovoltaic device comprises a carrier 10, one or more microalgae cells 20, an electrolyte solution 30, a cathode 40, and a permeable separator 50, the electrolyte solution 30 being placed in a reaction chamber of a container 60.

[0013] The carrier 10 includes a plurality of conductive sheets 101 extending along a planar direction, and these conductive sheets 101 are electrically connected to one another. In this embodiment, these conductive sheets 101 are electrically connected to one another by conductive connectors 12, and one or more microalgae cells 20 are provided on these conductive sheets 101, each conductive sheet 101 having a first surface 101a and a second surface 101b opposite to the first surface 101a, and one or more microalgae cells 20 are provided on the first surface 101a and the second surface 101b of these conductive sheets 101, the carrier 10 is placed in an electrolyte solution 30, and the conductive sheets 101 may be, for example, metals such as aluminum, stainless steel or copper, or other conductive nonmetallic materials.

[0014] One or more microalgae cells 20 are immersed in an electrolyte solution 30, and the one or more microalgae cells 20 may be of the genus Spirulina sp., Anabaena sp., Oscillatoria sp., Chlorella sp., Chlorococcum sp. or a combination thereof. In one example, the microalgae cells 20 are of a single type of microalgae cells, but in some examples, the microalgae cells 20 may be of multiple types of microalgae cells. In one example, the microalgae cells 20 are green algae or cyanobacteria.

[0015] The electrolyte solution 30 can be used as a culture medium for algae and has light permeability. For example, Zarrouk medium or Bold Basal medium is adopted. Thereby, the one or more microalgae cells 20 immersed in the electrolyte solution 30 grow on the carrier 10 to form a microalgae layer, and the microalgae layer growing on these conductive sheets 101 is used as an anode.

[0016] The cathode 40 is installed in the electrolyte solution 30, and as the cathode 40, a conductive carbon paper or other cathode material available for an electrochemical cell can be adopted.

[0017] The separator 50 is installed in the electrolyte solution 30 and is provided between the anode and the cathode 40. The separator 50 can move ions such as hydrogen ions (H + ), hydroxide ions (OH - ), etc., and a proton exchange membrane, for example, a Nafion polymer membrane, a glass fiber membrane, an organic porous membrane, an inorganic porous membrane or filter paper, etc. can be adopted.

[0018] The conductive sheet 101 is plate-shaped, meaning its thickness can be ignored compared to its length and width, and each conductive sheet 101 has a first surface area (the sum of the surface area of ​​the first surface 101a and the surface area of ​​the second surface 101b). The cathode 40 may also be plate-shaped and has a second surface area 401, and the first and second surface areas 401 are defined as the area of ​​the portion in contact with the electrolyte solution 30. The ratio of the sum of the first surface areas of these conductive sheets 101 (i.e., the number of conductive sheets 101 multiplied by the surface area of ​​each conductive sheet 101) to the second surface area 401 of the cathode 40 is between 32 and 64, and in one example, the ratio is between 44 and 52. By appropriately selecting the ratio of the first surface area to the second surface area 401, the power generation efficiency of the photovoltaic device can be optimized with the use of the minimum amount of electrode material.

[0019] These conductive sheets 101 and cathode 40 are electrically connected to the load 70 by an anode connector 11 and a cathode connector 41, respectively. The microalgae layer is a photosynthetic organism, and upon receiving light 80, one or more microalgae cells 20 immersed in the electrolyte solution 30 grow on these conductive sheets 101 to form the microalgae layer. The microalgae layer performs photosynthesis, dissociating the surrounding electrolyte solution to obtain oxygen, protons, and electrons, i.e., performing water photolysis, thereby forming an electrochemical cell with the electrolyte solution 30 and cathode 40 to supply power to the load 70. The electrons obtained by dissociation move from the anode to the cathode 40, and the oxygen and protons are reduced to water at the cathode 40. The microalgae layer may also be filamentous cyanobacteria. By utilizing a configuration consisting of multiple conductive sheets 101 and a filamentous microalgae layer, the surface area of ​​the microalgae layer can be significantly increased.

[0020] The present invention will be described more specifically below with reference to experimental examples; however, the experimental examples of the present invention are not limited to the following and may be modified as appropriate.

[0021] Figure 2 shows the configuration of the photovoltaic device used in the experimental example. An acrylic tubular container 60a is used as the container 60, with an inner diameter of approximately 36 mm and a height of approximately 100 mm. An electrolyte solution 30 is poured into the tubular container 60a, with a volume of approximately 40 mL. The tubular container 60a is placed on a support plate 90.

[0022] The carrier 10 consists of six sheets of aluminum foil, and the surface area of ​​one side of the aluminum foil is approximately 8 cm². 2 The microalgae cells 20 employ the genus Spirulina, and these Spirulina cells are placed on two sides of the aluminum foil. The surface area of ​​the carbon paper of the cathode 40 is approximately 2 cm². 2 The carbon paper is placed at the bottom of the tubular container 60a, and only the upper surface of the carbon paper is exposed to the electrolyte solution 30. Therefore, the first surface area of ​​the carrier 10 is approximately 96 cm². 2 Therefore, the second surface area 401 of cathode 40 is approximately 2 cm². 2 That is the case.

[0023] In the experimental example, light 80 is generated using a 10W light-emitting diode and irradiated in a 12-hour light-dark cycle, with the anode connector 11 and cathode connector 41 connected to a multimeter 71. In one example, the photovoltaic device generates a peak voltage greater than 450mV.

[0024] Figure 3 shows a photograph of the photovoltaic device used in the experimental example. The operation and measurement period for the photovoltaic device was approximately two weeks. Figure 4 shows the voltage and current of the photovoltaic device over these two weeks, with line segment L1 representing voltage and line segment L2 representing current. In the first week, the voltage of the photovoltaic device was in the range of 400mV to 600mV, but in the second week, the voltage of the photovoltaic device reached over 600mV, with a peak voltage of approximately 972mV during this two-week period, and the measured current was in the range of 1.0mA to 8.0mA. Observation of the microalgae layer on the carrier 10 revealed, as shown in Figure 5, that a new microalgae layer had grown on the carrier 10 in the second week. This new microalgae layer contributes to the photodegradation of water and therefore provides a high voltage.

[0025] To test whether the photovoltaic device meets the requirements for commercial use, the experimental example further connects six of the photovoltaic devices in series to form a photovoltaic device group, as shown in Figure 6. The operation and measurement period of this photovoltaic device group continued for approximately 3.5 weeks. The peak voltage measured in this manner was 4.74V, the current was in the range of 2.0mA to 7.0mA, and the voltage was in the range of 3V to 4.74V. Figure 7 shows the voltage and current of the photovoltaic device group over this 3.5-week period, with line segment L3 representing voltage and line segment L4 representing current. Figure 8 further shows that each of the photovoltaic devices can drive and light up a light-emitting diode (LED) bulb, with Figures 8(a) to (d) showing the illumination of red, green, white, and pink LED bulbs, respectively.

[0026] Table 1 shows the voltage range measured by photovoltaic devices employing different microalgae cells. Figure 9 shows the voltage and current when using the configuration shown in Figure 1, with line segment L5 representing the Spirulina genus, line segment L6 representing the Oschilatoria genus, line segment L7 representing the Chlorococcus genus, line segment L8 representing the Anabaena genus, and line segment L9 representing the Chlorella genus. Because the experimental flow in Figure 9 differs from that in Figure 4, even if the same configuration is used (i.e., line segment L5 in Figure 9 and line segment L1 in Figure 4), there will be differences in the data. [Table 1]

[0027] To verify that the photovoltaic device of the present invention can achieve better power generation efficiency, Table 2 compares the peak voltage measured in an experimental example with the configuration shown in Figure 1 with an experimental example based on the literature: Ahiahonu, E., Anku, WW, Roopnarain, A., Green, E., Serepa-Dlamini, MH, & Govender, PP (2022). Exploring indigenous freshwater chlorophytes in integrated biophotovoltaic system for simultaneous wastewater treatment, heavy metal biosorption, CO2biofixation and biodiesel generation. Bioelectrochemistry, 147, 108208. [Table 2]

[0028] According to the present invention, by utilizing a configuration that combines filamentous cyanobacteria in a microalgae layer with multiple conductive sheets 101, the surface area of ​​the microalgae layer can be significantly increased. Furthermore, by controlling the ratio of the first surface area to the second surface area, the photovoltaic device can achieve good power generation efficiency with low-cost materials and configuration. [Explanation of Symbols]

[0029] 10 Carriers 11 Anode Connectors 101 Conductive Sheet 101a First surface 101b Second surface 12 connectors 20 Microalgae cells 30 Electrolyte solution 40 Cathode 401 Second surface area 41 Cathode Connector 50 Separators 60 containers 60a Tubular container 70 load 71 Multimeter 80 light 90 Support Plate L1, L2, L3, L4, L5, L6, L7, L8, L9 line segment

Claims

1. A carrier comprising a plurality of conductive sheets extending along a planar direction, wherein these conductive sheets are electrically connected to one another, One or more microalgae cells provided on the carrier, the microalgae cells being of the genera Spirulina, Anabaena, Oschilatoria, Chlorella, Chlorococcus, or a combination thereof, The cathode is a conductive material, A permeable separator is provided between the carrier and the cathode, It can be used as a culture medium for algae, and is light-permeable, comprising an electrolyte solution that comes into contact with the cathode and the microalgae cells, Each of the conductive sheets has a first surface area on which the microalgae cells are provided and which is in contact with the electrolyte solution, and the cathode has a second surface area in contact with the electrolyte solution, and the ratio of the sum of the first surface areas of these conductive sheets to the second surface area of ​​the cathode is 32 to 64, and the microalgae cells capture sunlight in the electrolyte solution and grow as a microalgae layer on these conductive sheets to become anodes. A photovoltaic device made from renewable biomaterials.

2. The photovoltaic device according to claim 1, further comprising a light-transmitting container and a reaction chamber determined by the container, wherein the anode, the cathode, and the electrolyte solution are provided in the reaction chamber.

3. The photovoltaic device according to claim 1, wherein the microalgae cells are green algae or cyanobacteria.

4. The photovoltaic device according to claim 1, wherein the separator is a Nafion polymer membrane, a glass fiber membrane, an organic porous membrane, an inorganic porous membrane, or filter paper.

5. The photovoltaic apparatus according to claim 1, wherein the electrolyte solution is Zarrouk medium or Bold Basal medium.

6. The photovoltaic device according to claim 1, wherein the ratio is 44 to 52.

7. The photovoltaic device according to claim 1, wherein the photovoltaic device generates a peak voltage greater than 450 mV.

8. A group of photovoltaic devices comprising a plurality of photovoltaic devices according to any one of claims 1 to 7, wherein the photovoltaic devices are connected in series with each other.

9. The photovoltaic device group according to claim 8, wherein the photovoltaic device group provides a current of at least 2 mA.

10. The photovoltaic device group according to claim 8, wherein the photovoltaic device group provides a voltage of at least 3V.

Images