Photovoltaic device prepared from regrowth biological material

Abstract

A photovoltaic device made of a regrowable biological material, comprising a carrier comprising a plurality of electrically conductive sheets extending in a planar direction, the electrically conductive sheets being electrically connected to each other, one or more microalgae cells disposed on the carrier, a cathode disposed on the carrier, a permeable membrane disposed on the cathode, and an electrolyte solution disposed on the permeable membrane. The permeable diaphragm is arranged between the carrier and the cathode, the electrolyte can be used as an algae culture medium and is in contact with the cathode and the microalgae cells, each conducting strip is provided with a first surface area which is used for arranging the microalgae cells and is in contact with the electrolyte, the cathode is provided with a second surface area which is in contact with the electrolyte, and the second surface area is in contact with the electrolyte. The microalgae cells capture sunlight in the electrolyte and grow a microalgae layer on the conductive sheets to serve as an anode.

Description

[0001] A photovoltaic device made from reproducible biomaterials

[0002] [Technical Field of the Invention] The present invention relates to a photovoltaic device, and more particularly to a photovoltaic device made from regenerable biomaterials.

[0003] [Prior Art] Traditional photovoltaic devices (also known as solar cells) mostly use semiconductor materials, with silicon being the most common. Other materials include GaAs, GaAlAs, InP, CdS, and CdTe. With the increasing demand for renewable energy, the use of semiconductor or compound materials required for traditional photovoltaic devices has also increased. Furthermore, the energy consumption, environmental pollution, and high costs associated with the production and recycling of these materials have become increasingly discussed and criticized. In particular, for photovoltaic devices with high power generation efficiency, higher purity materials are required, making these issues even more significant. Recently, biophotovoltaic devices have been proposed as a cleaner and more energy-efficient way to produce photovoltaic devices, such as US9730433B2, US20120325290A1, and US8373064B2. However, existing biophotovoltaic devices suffer from poor power generation efficiency, and therefore, there is still a need for improvement.

[0004] SUMMARY OF THE INVENTION The present invention provides a photovoltaic device made from reproducible biomaterials, comprising a carrier, one or more microalgae cells, a cathode, a permeable membrane, and an electrolyte. The carrier comprises a plurality of conductive sheets extending along a planar direction and electrically connected to each other. The microalgae cells are disposed on the carrier and are of the genus Spirulina, Anabaena, Oscillatoria, Chlorella, Chlorella, or a combination thereof. The cathode comprises a conductive material. The permeable membrane is disposed between the carrier and the cathode. The electrolyte can serve as an algae culture medium and contacts the cathode and the microalgae cells. Each of the conductive sheets has a first surface area for the microalgae cells to be disposed on and in contact with the electrolyte. The cathode has a second surface area in contact with the electrolyte. The ratio of the sum of the first surface areas of the conductive sheets to the second surface area of ​​the cathode is between 32 and 64. The microalgae cells capture sunlight within the electrolyte and grow a microalgae layer on the conductive sheets, serving as an anode. In one embodiment, the apparatus further includes a light-transmitting container and a reaction chamber defined by the container, wherein the anode, cathode, and electrolyte are disposed within the reaction chamber. In one embodiment, the microalgae cells are green algae or blue algae. In one embodiment, the separator is a Nafion polymer membrane, a glass fiber membrane, an organic porous membrane, an inorganic porous membrane, or filter paper. In one embodiment, the electrolyte is Zarrouk's medium or Bold Basal medium. In one embodiment, the ratio is between 44 and 52. In one embodiment, the photovoltaic device generates a peak voltage greater than 450 mV. In one embodiment, the photovoltaic devices are connected in series. In one embodiment, the photovoltaic device group provides a current of at least 2 mA. In one embodiment, the photovoltaic device group provides a voltage of at least 3 V. [Brief Description of Figures] The designated representative figure is: [Figure 1]

[0005] FIG1 is a schematic diagram of a photovoltaic device according to an embodiment of the present invention.

[0006] FIG2 is a schematic diagram of a photovoltaic device according to an experimental example of the present invention.

[0007] FIG3 is a photograph of a photovoltaic device according to an experimental example of the present invention.

[0008] FIG4 is a graph showing the voltage and current data for the experimental example in FIG3.

[0009] Figure 5 is a photograph of the experimental example in Figure 3 at the second week.

[0010] FIG6 is a photograph of a photovoltaic device assembly according to an experimental example of the present invention.

[0011] FIG7 is a graph showing the voltage and current data for the experimental example in FIG6 .

[0012] Figure 8 is a photograph of the light-emitting diode bulb in the experimental example of Figure 6 being lit.

[0013] FIG. 9 is a graph showing voltage and current data for different microalgae cells used in an experimental example of the present invention.

[0014] [Implementation Methods] Although terms such as "first," "second," and the like are used herein and in the claims to describe certain elements or features, these terms are not intended to limit these elements or features. These terms are used solely to distinguish one element or feature from another. For example, a first element or feature can be interpreted as a second element or feature, and similarly, a second element or feature can be interpreted as a first element or feature. When an element is referred to as being "on," "overlying," or "over" another element, it can be directly on, directly overlying, or directly over that element; or other elements may be present intervening. Conversely, when an element is referred to as being "directly on," "directly overlying," or "directly over" another element, there are no intervening elements. The terms used herein and in the claims are for the purpose of describing specific examples only and are not intended to be limiting. Unless the context clearly indicates otherwise or the number of elements is intended to be limited, the singular forms "a," "an," and "the" are intended to include the plural forms. It will be further understood that the terms "comprise" and / or "include," when used herein, indicate the presence of the recited features, elements, and / or components, but do not preclude the addition or presence of one or more other features, elements, components, and / or groups thereof. Indefinite and definite articles include the plural as well as the singular, unless the context clearly indicates otherwise. Unless otherwise indicated, all numerical values ​​for sizes, quantities, and physical properties used herein and in the claims are to be understood as being modified in all instances by the term "about." Therefore, unless otherwise indicated, the numerical parameters listed herein and in the claims are approximate values, which can be appropriately varied by those skilled in the art using the disclosure herein and in the claims to obtain the desired properties. The use of numerical ranges by endpoints includes all values ​​within that range as well as any range within that range; for example, 1 to 5 includes values ​​such as 1, 1.2, 1.5, 1.7, 2, 2.75, 3, 3.80, 4, and 5.The present invention discloses a photovoltaic device fabricated from reproducible biomaterials. Referring to FIG. 1 , in one example, the photovoltaic device comprises a carrier 10, one or more microalgae cells 20, an electrolyte 30, a cathode 40, and a permeable membrane 50. The electrolyte 30 is placed within a reaction chamber of a container 60. The carrier 10 includes a plurality of conductive sheets 101 extending along a planar direction, and the conductive sheets 101 are electrically connected to each other. In this embodiment, the conductive sheets 101 are electrically connected to each other via a conductive connector 12. The conductive sheets 101 are used to accommodate one or more microalgae cells 20. Each conductive sheet 101 has a first surface 101 a and a second surface 101 b opposite the first surface 101 a. The one or more microalgae cells 20 are disposed on the first surface 101 a and the second surface 101 b of the conductive sheets 101. The carrier 10 is placed in the electrolyte 30. The conductive sheets 101 can be made of metal, such as aluminum, stainless steel, or copper, or other conductive non-metallic materials. One or more microalgae cells 20 are immersed in the electrolyte 30. The one or more microalgae cells 20 may be of the genus Spirulma, Anabaena, Oscillatoria, Chlorella, Chlorococcum, or a combination thereof. In one example, the microalgae cells 20 are of a single species. In other examples, the microalgae cells 20 may be of multiple species. In one example, the microalgae cells 20 are green algae or cyanobacteria. The electrolyte 30 is a medium capable of culturing algae and is light-transmissive, such as Zarrouk's medium or Bold Basal medium. Thus, one or more microalgae cells 20 immersed in the electrolyte 30 grow on the carrier 10 to form a microalgae layer. The microalgae layer grown on the conductive sheets 101 serves as an anode. The cathode 40 is placed in the electrolyte 30 and can be made of conductive carbon paper or other cathode materials suitable for use in electrochemical cells.The separator 50 is placed in the electrolyte 30 and disposed between the anode and the cathode 40. The separator 50 allows the movement of ions such as hydrogen ions (H+) and hydroxide ions (OH-). A proton exchange membrane, such as a Nafion polymer membrane, a glass fiber membrane, an organic porous membrane, an inorganic porous membrane, or filter paper, can be used. The conductive sheet 101 is flat, i.e., its thickness is negligible compared to its length and width. Each conductive sheet 101 has a first surface area (the surface area of ​​the first surface 101a plus the surface area of ​​the second surface 101b). The cathode 40 can also be flat and have a second surface area 401. The first surface area and the second surface area 401 are defined as the area of ​​the portion in contact with the electrolyte 30. The ratio between the sum of the first surface areas of the conductive sheets 101 (i.e., the number of conductive sheets 101 multiplied by the surface area of ​​each conductive sheet 101) and the second surface area 401 of the cathode 40 is between 32 and 64. In one example, the ratio is between 44 and 52. By appropriately selecting the ratio between the first surface area and the second surface area 401, the photovoltaic device's power generation efficiency can be optimized while minimizing the use of anode and cathode materials. The conductive sheets 101 and the cathode 40 are electrically connected to a load 70 via an anode connector 11 and a cathode connector 41, respectively. The microalgae layer is a photosynthetic organism. When exposed to light 80, one or more microalgae cells 20 immersed in the electrolyte 30 grow on the conductive sheets 101. The microalgae layer undergoes photosynthesis, dissociating the surrounding electrolyte into oxygen, protons, and electrons (a process known as water photolysis). This, along with the electrolyte 30 and the cathode 40, forms an electrochemical cell, providing power to the load 70. The dissociated electrons migrate from the anode to the cathode 40, where the oxygen and protons are reduced to water. The microalgae layer can be filamentous cyanobacteria. The configuration of multiple conductive sheets 101 and the filamentous structure of the microalgae layer significantly increases the surface area of ​​the microalgae layer.The present invention is described in more detail below through experimental examples. However, the experimental examples of the present invention are not limited to the following content and can be appropriately changed.

[0015] Figure 2 shows the configuration of the photovoltaic device used in the experimental example. The container 60 is a tubular container 60a made of acrylic, with an inner diameter of approximately 36 mm and a height of approximately 100 mm. The electrolyte 30 is injected into the tubular container 60a, with a volume of approximately 40 ml. The tubular container 60a is placed on a support plate 90°. The carrier 10 is composed of six sheets of aluminum foil, each with a surface area of ​​approximately 8 cm². The microalgae cells 20 are Spirulina, placed on both sides of the aluminum foil. The surface area of ​​the carbon paper of the cathode 40 is approximately 2 cm². The carbon paper is placed at the bottom of the tubular container 60a, with only the top surface of the carbon paper exposed to the electrolyte 30. Therefore, the first surface area of ​​the carrier 10 is approximately 96 cm². 2 The second surface area 401 of the cathode 40 is approximately 2 cm². In an experimental example, a 10W light-emitting diode was used to generate the illumination 80, and illumination was performed with a 12-hour light-dark cycle. The anode connector 11 and the cathode connector 41 were connected to a multimeter 71. In one example, the photovoltaic device generated a voltage peak greater than 450 mV.

[0016] Figure 3 shows a photograph of the photovoltaic device used in the experimental example. The photovoltaic device was operated and measured for approximately two weeks. The voltage and current of the photovoltaic device during these two weeks are shown in Figure 4. Line segment L1 represents the voltage, and line segment L2 represents the current. In the first week, the voltage of the photovoltaic device ranged from 400 mV to 600 mV. In the second week, the voltage exceeded 600 mV. The peak voltage during these two weeks was approximately 972 mV, and the measured current ranged from 1.0 mA to 8.0 mA. Observation of the microalgae layer on the carrier 10 revealed that a new layer of microalgae had grown on the carrier 10 in the second week, as shown in Figure 5. This new layer of microalgae aided water photolysis, thereby providing a higher voltage. To test the suitability of the photovoltaic device for commercial applications, the experimental example further connected six photovoltaic devices in series to form a photovoltaic device cluster, as shown in Figure 6. The photovoltaic device was operated and measured for approximately 3.5 weeks. The measured peak voltage was 4.74 V, the current ranged from 2.0 mA to 7.0 mA, and the voltage ranged from 3 V to 4.74 V. The voltage and current of the photovoltaic device during these 3.5 weeks are shown in Figure 7, with line segment L3 representing the voltage and line segment L4 representing the current. Figure 8 further demonstrates that the photovoltaic device can drive and illuminate LED bulbs. (a) through (d) of Figure 8 show the illumination of red, green, white, and pink LED bulbs, respectively. Table 1 shows the voltage ranges measured by photovoltaic devices using different microalgae cells. Using the configuration shown in Figure 1J, the voltage and current are shown in Figure 9. Line segment L5 represents the use of Spirulina, line segment L6 represents the use of Oscillatoria, line segment L7 represents the use of Chlorella, line segment L8 represents the use of Anabaena, and line segment L9 represents the use of Chlorella. Since the experimental example of Figure 9 was conducted differently from that of Figure 4, even if the same configuration is used (i.e., line segment L5 of Figure 9 and line segment L1 of Figure 4), the data are still different. Table 1 To verify that the photovoltaic device of the present invention can achieve better power generation efficiency, Table 2 compares the peak voltage measured based on the experimental example according to the configuration shown in Figure 1J and the experimental example prepared according to the following literature: Ahiahonu, EK, Anku, WW, Roopnarain, A., Green, E., Serepa-Dlamini, M. H., & Govender, PP (2022). Exploring indigenous freshwater chiorophytes in integrated biophotovoltaic system for simultaneous wastewater treatment, heavy metal biosorption, CO2 biofixation and biodiesel generation. Bio electro chemistry, 147, 108208. Table 2 According to the present invention, the filamentous blue-green algae in the microalgae layer, combined with the configuration of multiple conductive sheets 101, can significantly increase the surface area of ​​the microalgae layer. Furthermore, by controlling the ratio between the first surface area and the second surface area, the photovoltaic device can achieve excellent power generation efficiency using low-cost materials and configurations.

Claims

Claims [Scope of patent application] 1. A photovoltaic device made of reproducible biomaterials, characterized in that: The invention comprises: a carrier comprising a plurality of conductive sheets extending in a planar direction, the conductive sheets being electrically connected to each other; one or more microalgae cells disposed on the carrier, the microalgae cells being of the genus Spirulina, Anabaena, Oscillatoria, Chlorella, Chlorella, or a combination thereof; a cathode comprising a conductive material; a permeable membrane disposed between the carrier and the cathode; and a light-transmissive electrolyte capable of serving as an algae culture medium, contacting the cathode and the microalgae cells. Each conductive sheet has a first surface area for the microalgae cells to be located and in contact with the electrolyte. The cathode has a second surface area in contact with the electrolyte. The ratio of the sum of the first surface areas of the conductive sheets to the second surface area of ​​the cathode is between 32 and 64. The microalgae cells capture sunlight in the electrolyte and grow a microalgae layer on the conductive sheets, which serves as an anode.

2. The photovoltaic device according to claim 1, characterized in that The invention also includes a light-transmitting container and a reaction chamber defined by the container, wherein the anode, the cathode and the electrolyte are arranged in the reaction chamber. The photovoltaic device according to claim 1, characterized in that The microalgae cells are green algae or blue algae. The photovoltaic device according to claim 1, characterized in that The diaphragm is a Nafion polymer membrane, a glass fiber membrane, an organic porous membrane, an inorganic porous membrane or filter paper. The photovoltaic device according to claim 1, characterized in that The electrolyte is Zarrouk's medium or Bold Basal's medium. The photovoltaic device according to claim 1, characterized in that The ratio ranges from 44 to 52. The photovoltaic device according to claim 1, characterized in that The photovoltaic device generates a peak voltage greater than 450 millivolts. A photovoltaic device group comprises a plurality of photovoltaic devices according to any one of claims 1 to 7, wherein the photovoltaic devices are connected in series. The photovoltaic device group according to claim 8, characterized in that: The photovoltaic device array provides a current of at least 2 milliamperes. The photovoltaic device group according to claim 8, characterized in that The photovoltaic device array provides a voltage of at least 3 volts.

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