TW201424195A - An indoor system and method of manufacturing an indoor system - Google Patents

Abstract

An indoor system comprises: a control unit; a rechargeable energy storage medium configured to provide power; and an energy harvesting module configured to generate electric power for charging the storage medium. The energy harvesting module may comprise a DSSC module. The DSSC module may comprise a single DSSC cell configured to output a voltage that is boosted by a voltage booster to a fixed or variable output voltage. Alternatively the DSSC module may comprise a plurality of DSSC cells connected in series. In the latter case the device may be configured so that the DSSC module may charge the storage medium directly. The system may be used for increasing the energy efficiency of a building, alternatively for environmental monitoring for comfort or horticulture.

Description

Indoor system and method of manufacturing an indoor system

The present invention relates to an indoor system and a method of manufacturing an indoor system.

Energy power generation has undergone many stages of evolution, from whale oil and charcoal to oil, and now into a new generation of so-called renewable energy. Such renewable energy sources include solar energy, biomass, geothermal energy, ocean currents and tidal energy, surges and wind energy. Petroleum-based power generation is the main energy source used in developed countries to date, including: its abundant reserves, easy transportation, mature industrial and refining processes, high usefulness of by-products, and can be realized at every point in the supply chain. Considerable business value added. World annual crude oil consumption reached 85 million barrels per day in 2009 and continues to increase. However, petroleum fossil fuels are depleting and global availability will fall sharply over the next few decades. Burning fossil fuels is also widely recognized as one of the main causes of climate change and an important source of environmental pollution. Efforts to reduce dependence on petroleum fuels are currently focused on renewable energy and focus on reducing energy use by efficiency measures. It is an object of the present invention to provide a renewable energy source for a device (such as a sensor, a controller, and a low power display) for facilitating energy savings in a building using an indoor energy harvesting device.

About 40% of global energy use is for buildings. And in the 40%, half is wasted. In other words, 20% of the world's energy consumption is a loss and can be saved. Minimizing this loss can effectively reduce energy consumption.

In the prior art, a sensor application using a dye sensitized solar cell (DSSC) has been described (US 2007/0132426-A1). However, we have found that the description given in this patent is coarser and the output parameters are too broad. In the fourth aspect of the invention, it is said that "it has a photoelectric conversion efficiency of 8% or higher, an open circuit voltage of between 0.6V and 0.7V, and a unit cell of between 10 mA/cm ² and 12 mA/cm ² . A short circuit current density". This has a very significant difference from DSSC, one of the sensor applications. Although data can be generated by a DSSC (a battery suitable for indoor or outdoor use), the sensor application should focus on a significantly lower current range. Indoor energy harvesting is widely accepted in the industry: 200 lux intensity fluorescent lamps or LED lights indicate a standard test condition for moderately illuminating a room. A state of the art DSSC can provide a power output of 6 μW/cm ² to 8 μW/cm ² under these conditions. Consider the size of the module specified in the patent solution 14 (30 mm × 30 mm) (which is equal to 9 cm ² ), so that the power delivered by the battery in the short circuit will not exceed 72 μW, which is lower than the power recommended in the request. One to three orders of magnitude. Therefore, the actual operating conditions described in this patent are strongly questioned. The specified operating voltage is also questionable. The technical solution 5 and the technical solution 13 specify that "one of the voltages supplied by the solar cell is in a range between 1.6V and 3.5V". Since the voltage output of a DSSC only falls between 0.5V and 0.7V, and the output is biased to the low end of the range under indoor illumination to obtain a 1.6V to 3.5V output voltage, it must be within the module. Four to seven batteries are connected in series. This is not a worthless task given the small size (9 cm ² ) of the claimed DSSC module. The description given in this patent does not explain how the DSSC module can supply an output voltage of 1.6V to 3.5V. For this reason, we often doubt the validity of this prior art.

According to the present invention, there is provided an indoor system comprising: an electronic control unit; a rechargeable energy storage medium configured to provide power to other components of the indoor system; and an energy harvesting module Configured to generate electrical power for charging the rechargeable storage medium.

According to the present invention, there is provided a method of manufacturing an indoor system, wherein the indoor system comprises: an electronic control unit; a rechargeable energy storage medium configured to provide electrical power to other components of the indoor system; An energy harvesting module configured to generate electrical power for charging the rechargeable storage medium.

Figure 1 depicts the principle of DSSC operation; Figure 2 shows the power output performance of the DSSC; Figure 3 shows the power output performance of the DSSC; Figure 4 shows the application for defect passivation of the high performance weak light DSSC; Figure 5 shows the TiO ₂ layer Comparison of DSSC performance under low light when the structure and thickness are changed; FIG. 6 is a schematic diagram of one DSSC module made up of a plurality of batteries connected in series; FIG. 7 shows a detailed device top view; FIG. 8 shows a DSSC A circuit diagram of one of the single battery modules; and FIG. 9 shows a top view of the device of the DSSC battery module.

There are many energy usage scenarios in buildings that can be modified according to efficiency, including temperature control (heating and cooling), lighting, humidity control, security, and safety systems. Different levels of efficiency can be implemented using systems with varying degrees of complexity, intelligence, or "intelligence." In order to create a "smart" building, all possible energy waste must be minimized. In the residential consumer market, efficiency can be introduced into lighting, heating, and consumer electronics such as audiovisual, computing, and related equipment and air conditioners. Offices and commercial buildings can achieve efficiency in a very large number of identical areas, and both energy savings and relative energy savings can be even greater in such settings. Most of the energy in office and commercial buildings is only used during business hours, so if the power supply is not reduced or disconnected at the end of the working day, the power supply will continue to supply wasted energy until the next working time. Especially huge energy waste may be issued Born during the entire weekend or holiday period, the ratio of non-working time to working time increases during this period.

These energy conservation systems are also suitable and often compatible with monitoring and controlling residential comfort levels (eg, by air quality monitoring) or other environmental requirements (eg, horticultural control) while minimizing energy consumption. The intelligence and complexity of this sensing and control system depend on design and operation.

However, the more intelligent and complex the system, the more power it will consume. Therefore, an advanced, intelligent and complex monitoring and control system that results in efficient operational energy savings and high comfort will necessitate devices that require increased power. Considering the energy and environmental impacts that can be saved, the development of intelligent control systems is still considered beneficial. However, the adoption of such systems is in its infancy, which is due in large part to the challenges and costs associated with installation and maintenance.

The components of each device in an intelligent system can include a functional unit, an electronic control and signal transceiver unit, and a power supply. The functional unit can detect or transmit one or more of one of the sensors, the actuator, the display or other components of the information. The selection and design of the power supply is particularly important because it determines the allowable complexity of the device, the cost of components and maintenance, and the reliability and functionality of the entire system over its service life. Therefore, the choice and/or design of the power supply is extremely important.

In building management systems, "smart" sensing and control relies on the use of information from the internal environment to determine whether to cut, reduce or otherwise modify the energy usage in the building system. To achieve this efficiency, a variety of different sensing heads are needed for different purposes, such as light, temperature, humidity, motion or presence, and air quality. Unfortunately, the function of one sensor head is often quite different from the function of another sensor head. Therefore, sensors for multitasking functions required for effective energy savings have higher energy consumption. Regardless of how many sensing heads are used in the sensor unit, it is still desirable to use a single power supply (or power supply). However, the demand for this single power supply therefore increases with the number of sensing heads. Display and actuation in other wireless systems in buildings The device increases the power demand according to the frequency of changes in its state.

Basically, there may be three types of energy sources. The first type of energy source is a direct connection or other physical connection to the local power facility. The second type of energy is the use of disposable primary batteries (a standard battery). The third type of energy source is an energy harvesting device that uses one of the energies that can be used for the life of the entire device.

The first type of energy (a wired source) requires the installation of wires and connectors. These are typically ducted cables that pass through and along the wall and are located within the cavity of the building. This is expensive during building construction and installation, especially when refurbishment and power lines or connectors are damaged due to aging or other degradation to require maintenance and repair.

The second type of energy (using dry batteries) seems to be a convenient solution. But dry batteries usually have a very limited life. It also creates an environmental problem that is subject to cleaning and disposal within the regulations prescribed by local law. The need for frequent replacement is another management issue with associated costs. When a battery is exhausted and not replaced, the building loses its sensing and control system.

A third type of energy source is one of a solar energy (photovoltaic (PV)) battery energy harvesting device coupled to a power management and energy storage component that provides a reliable power source to the device.

For PV cells, most known energy harvesting devices operate only at outdoor light intensities and spectra. Very few solar cells work efficiently in indoor low light and highly diffuse light environments. This is because indoor lighting is usually less than 2.5% of outdoor light intensity. Most indoor light sources are spectrally shifted toward white light and are highly diffusive, which is a typical light source design to give uniformity and energy efficiency while maintaining a comfortable light level.

Amorphous germanium (a-Si) photovoltaic cells are only known commercial energy harvesting devices that have been successfully used in indoor lighting. Its performance results from its spectral response centered at 1.7 eV (730 nm) and can be fine tuned to shift this peak. However, a-Si suffered two problems. First, there are long-term stability issues under exposure that cannot be solved by an easy solution. this It is attributed to the so-called "Staebler-Wronski" effect caused by the unstable dangling bonds formed in the battery when depositing a film. This effect becomes more severe if the battery is operated in a humid environment. The second problem concerns the desire to produce higher power densities (i.e., the power per unit area of the photovoltaic cell is greater) to give smaller modules that can still power higher level devices. Since the technology of a-Si has existed for nearly forty years and has matured in the past two decades, new breakthroughs are unlikely to bring about a step change in performance. Organic Photovoltaic Cells (OPV) can also be considered as one of the technologies that compete with a-Si and dye-sensitized solar cells (DSSC); however, it has been reported that the power conversion efficiency of OPV is much lower than that of both a-Si and DSSC. .

In the present invention, a dye-sensitized solar cell (DSSC) is used as an energy harvesting power source for indoor sensor applications as an improvement to a-Si that enables the described system. DSSC as a preferred photovoltaic cell for indoor use has several advantages over a-Si. First, DSSC has proven to be extremely stable and capable of surviving an equivalent life of more than 20 years in accelerated testing. Second, even when DSSC is currently in its premature development status, DSSC still produces electrical power with a higher regional density than a-Si. The principles of DSSC operation have been widely published and are recognized as shown in FIG. A key description of DSSC has been given below by published materials (Hagfeldt et al, Chem. Rev., 2010, 110, pages 6595 to 6663).

A mesoporous oxide layer is located at the center of the device, the mesoporous oxide layer being composed of metal oxides (eg, TiO ₂ ) that have been sintered together to establish electron conduction across the photoelectrode (also referred to as the working electrode (WE)). One of the rice particles is composed of a network. Usually, the film thickness is from 10 μm to 15 μm and the particle diameter of the nanoparticles is from 10 nm to 30 nm. The porosity is 50% to 60%. The mesoporous layer is deposited on a transparent conductive oxide (TCO) on a glass or other substrate. The most commonly used substrate is a glass coated with fluorine-doped tin oxide (FTO). A single layer of charge transfer dye sensitizer is attached to the surface of the mesoporous oxide layer. Photoexcitation of the dye sensitizer causes electrons to be injected into the conduction band of the oxide and the dye in its oxidized state. The dye is returned to its ground state by transferring electrons from an electrolyte, which is typically an organic solvent containing one of the iodide/triiodide redox system. Thus, the sensitizer dye is regenerated from the iodide by intercepting the recapture of the conduction band electrons. With the I ^- I of the oxidized form of ₃ ^- ions diffuse a short distance (less than 50 m) to pass through the electrolyte to the cathode (also referred to as counter electrode (CE)). The CE is coated with a thin layer of platinum catalyst in which the regeneration cycle is completed by electron transfer to reduce I ₃ ^- to I ^- . The circuit is completed via the externally applied load between CE and WE.

The potential generated under illumination corresponds to the difference between the Fermi level of the electrons in the mesoporous layer and the redox potential of the electrolyte. Therefore, the open circuit voltage (Voc) of a typical DSSC is a function of the metal oxide semiconductor Fermi level in WE, and the chemical potential of the electrolyte containing the iodide and triiodide redox system, and the concentration of the electrolyte. . The maximum possible Voc of a DSSC containing a TiO ₂ WE and an iodide/triiodide redox system in its electrolyte is about 0.9V.

WE can be formed by printing a nanoporous metal oxide paste (e.g., TiO ₂ ) on a FTO coated transparent conductive glass substrate. Scraper printing or screen printing is one of the most common printing techniques. After printing, drying, and sintering of TiO ₂ at about 500 ° C, WE is immersed in a dye bath containing one of the dye sensitizers. Sulfhydryl dyes are commonly used. The CE is formed by depositing a thin layer of platinum as a catalyst on the FTO coated glass by using vacuum sputtering, electroplating, electroless plating or printing (following sintering at about 450 ° C). Next, the electrodes are assembled and one of the sealants between the two electrode plates is used to form a fluid tight barrier around one of the cells. A UV curable sealant or a thermoplastic film is generally used as the sealing material. A controlled cell gap can be established by selecting one of the sealing materials to form the program correctly, the gap being the distance between the two electrodes. After assembly and sealing of the cell, the electrolyte is introduced into the pores of each of the cells that are pre-drilled through one of the counter electrode glass substrates. After filling, the holes are sealed.

Thus, electrons can be regenerated from the electrolyte iodide/triiodide redox system via a sensitizer and electrons are repeatedly supplied from the CE to the WE. The device generates electrical power from light and does not suffer from any permanent chemical transformation. For external loads, a DSSC behaves very similar to the other Type of photovoltaic battery.

However, DSSC photovoltaic cells have many unique features. The output potential varies little over a very wide range of light intensities. Even at low light as low as 200 lux, Voc remains as high as 0.5 V and even maintains 0.45 V at 50 lux. Thus, the proper design of the DSSC battery and module enables charging of an electronic device and proper operation of the electronic device under very dark light.

A state-of-the-art multi-junction a-Si cell (which consists of a-Si/nc-Si/nc-Si structure) has an efficiency of 12.5%. The state-of-the-art DSSC is reported to produce 11.4% power conversion efficiency (which is comparable to a-Si). However, a key point is that these records are obtained under the standard sun test of "One Sun" (which is 1000 W/m ² with an AM 1.5 spectrum (a simulated strong sunlight)) and therefore generally not used indoors. Related.

The indoor unit operates at much lower light intensities and in spectra that are significantly different from standard solar testing. Without exception, PV cells with reported recording performance have been configured and optimized for standard solar test conditions. Therefore, for indoor applications, new batteries must be designed to be optimized for room light intensity and spectrum. For these indoor light environments, due to the difficulty in expressing the total incident power in W/cm ² , accurately due to the complex combination of light intensity, spectrum and diffusion, the intensity is usually in luminous flux per unit area ("lux" ) is the unit, not the standard "one sun score", "W/m ² " or "W/cm ² ".

As a rule of thumb for approximate comparison, the "one sun" standard is approximately 120,000 lux. A typical indoor light environment can span from 50 lux to 3000 lux, which (as mentioned above) does not exceed about 2.5% of "one sun", which is very low strength compared to one of the standard tests.

All types of solar cells behave very differently between outdoor light conditions and indoor light conditions (especially between strong light conditions (such as "one sun") and low light conditions). For example, Randall and Jacot report this phenomenon (Renewable Energy, 2003, 28, pp. 1851 to 1864), and we now describe some of the findings of Randall and Jacot. When the incident light intensity is reduced from 1000W/m ² light intensity to 1W/m ² (1W/cm ² ) light intensity, the efficiency of the crystalline germanium battery will decrease from above 12% to 0%; at this level, a crystal The 矽 battery effectively produces zero power. The drop in the same range in an a-Si cell is significantly smaller, from 7% to 5.5%.

In the present invention, we focus on the energy harvesting device circuitry, electronics, and application requirements, and in particular, focus on managing the DSSC photovoltaic module voltage output and maximizing its power density. The indoor system of the present invention can have a functional unit that enables the indoor system to perform one function other than generating electrical power for charging the rechargeable storage medium and recharging the rechargeable energy storage medium. For example, the functional unit can be a sensing unit, a visual display, an actuator or an audio device.

In PVSEC, Hamburg 2011, Texas Instruments reported a comparison of indoor light energy harvesting capacity between organic PV (OPV), a-Si, and DSSC. In Figure 2, there are three columns at each light environment data point. The three pillars on the left indicate the power density of DSSC, OPV and a-Si from left to right. DSSC is three times better in this literature than OPV and a-Si. We report that the DSSC made by the inventors is further 40% better than the DSSC in this original document. Thus, under a fluorescent light source, the DSSC made by the inventors is 4.2 times better than OPV and a-Si, from 50 lux light intensity up to 10,000 lux light intensity.

This validated test data clearly states that DSSC produces much higher power densities than both a-Si and OPV in indoor low light conditions.

Under the LED light, which is used as an energy-saving lamp in most modern commercial lighting environments and with a spectrum very similar to the more common fluorescent lamps, the most advanced a-Si solar cells produce per cm under 100-lux illumination. ² 3μW one of the nominal power. This power output continues to increase from 100 lux at least up to 100,000 lux, and it is safe to assume an output linearity from 50 lux up to 1000 lux. As shown in Figures 2 and 3, the DSSC (as described in the present invention) can easily win on similarly linear power outputs under the same light conditions, as demonstrated by DSSCs up to 5000 lux and larger. Thus, for low light energy spectra, the PV power output under low light is practical in μW/cm ² /100 lux or μlux/cm ² increments of 100 lux. In the present invention, DSSC output power density is superior to the effectiveness of a-Si of the most advanced technology (which is 3.5μW / cm ² / 100lux), and further has superior 6μW across the range 50lux to 10000lux / cm ² /100lux. In the context of an energy harvesting device interior, this high conversion efficiency is a consistent factor in the application of indoor devices, such as sensor networks, and will become more critical as device power requirements for network nodes increase.

Modifications to the DSSC described by the inventors can be made to optimize performance in low light indoor environments.

Any embodiment of the invention may include passivation of defects on one or more inner surfaces, as the case may be. Defects on the surface of the internal material have a negative impact on DSSC performance. There are currently two major defect locations. One is a defect on a transparent conductive surface such as a fluorine-doped tin oxide (FTO) surface. The other is a defect on the working electrode of one of the working electrodes of a nanocrystalline porous titania.

FTO is an exemplary transparent conductor of one of the DSSCs that can be used in the present invention. Its surface usually has many defects, such as non-uniformity of the FTO coverage area. Electrons injected from the excited sensitizer into the TiO ₂ working electrode should be delivered to the external load through the FTO conductor. However, defects on the surface of the FTO can cause electrons to recombine with the oxidized sensitizer or iodide (the oxidized portion of the redox pair in the electrolyte), thus reducing overall cell efficiency.

On the other hand, the working electrode of the DSSC can be composed of TiO ₂ nanocrystalline particles. These nanocrystalline particles are typically produced at very low cost and with minimal refinement and purification procedures. Thus, similar to the FTO surface, the TiO ₂ surface is also covered with high density defects, which are the non-uniformities of the structure and/or composition of the titanium dioxide. At intense light intensities such as 1 sun (i.e., about 120,000 lux), the photocurrent is large and the number of recombination events and the resulting leakage current are not significant (comparatively). However, under low light conditions where the photocurrent is much lower than one solar condition (i.e., about 120,000 lux), the leakage current caused by the same defect density becomes more significant with respect to the photocurrent.

Such as the following techniques may be used to passivate the FTO and / or defects in the TiO _2: During the process, the reaction of the electrode immersed in the chemical solution (e.g. deg.] C of from about 70 to about 40mM TiCl ₄ solution) for approximately 30 minutes. After immersion in the chemical bath, the coated material (FTO coated glass or TiO ₂ nanocrystalline particles) may be sintered by air in a furnace in a period of from about 15 minutes to about 90 minutes. This passivation procedure is especially critical for a low light environment. This phenomenon has been studied and reported (LM Peter, J., Phys. Chem. C 2007, 111, pages 6601 to 6612). The parameters of the impregnation chemistry can vary within one of the surrounding optimization conditions. For example, the TiCl ₄ concentration, operating temperature, and immersion time can vary from about 20 mM to about 60 mM, from about 45 ° C to about 85 ° C, and from about 15 minutes to about 45 minutes, respectively.

Although a technique has been described by, for example, Ito et al. (Chem. Commun., 2005, pages 4351 to 4353) or by Kay et al. (US005525440A), such prior art has not been reported for a weak light. The advantages of this technology in DSSC energy in an indoor environment. In Figure 4, the inventors demonstrate the application for achieving defect passivation of high performance low light DSSCs.

Any embodiment of the invention may have a modified TiO ₂ working electrode layer structure, as the case may be. Standard DSSCs designed to operate under one solar condition (i.e., about 120,000 lux) have been extensively studied and the TiO ₂ layer structure and thickness have been optimized for high absorption and energy conversion under intense light. The structure comprises an absorber layer of a thickness of from 12 μm to 14 μm and a scattering layer of a thickness of from 5 μm to 6 μm (Ito et al., International Journal of Photoenergy Volume 2009, Article ID 517609). The absorbing layer consists essentially of ca. ₂₀ nm diameter TiO ₂ nanoparticles to result in a sintered porous structure having a very large surface area. The scattering layer consists essentially of ca. 400 nm diameter TiO ₂ having a significantly lower surface area. The absorbing layer almost fully supports the DSSC photocurrent due to its very large surface area.

The inventors of the present invention have discovered that this layer structure and thickness are not optimally designed in a very low light environment. This layer structure can be modified to optimize DSSC performance in low light environments. The thickness of the scattering layer can be kept constant, but the thickness of the absorbing layer can be reduced to, for example, between about 2 [mu]m and about 4 [mu]m to optimize performance. This minimizes the effect of defects on the surface of TiO ₂ by reducing the total surface area. Defects in the surface area of TiO ₂ result in an increase in the number of recombinations and result in a leakage current and poor overall conversion efficiency. The maximum photocurrent available is a function of one of the TiO ₂ surface areas. Therefore, a higher photocurrent will require a higher TiO ₂ surface area to support. Since the surface of TiO ₂ is covered with defects, an increased surface area may contain more defects. The photocurrent in a weak light environment is much lower than the photocurrent under strong light conditions. We expect that the light current of 10000 lux of incident light is less than 10% of the photocurrent of one sun (ie, about 120,000 lux). Therefore, the surface area can be reduced to supply the photocurrent.

Theoretically, the thickness of TiO ₂ can be reduced to 10% of the thickness of TiO ₂ for one solar condition, such as one thickness of about 1.5 μm. To maintain the limitations of screen printing of the titanium dioxide layer, the thickness of the titanium dioxide on the working electrode of from about 1.5 μm to about 5 μm has exhibited significant performance improvements in the final cell and remains when the thickness of the absorber layer approaches approximately 6 μm to about 7 μm. high efficiency. Therefore, the thickness of the absorbing layer may be about 1.5 μm to 7 μm for the low light state. In Fig. 5, the inventors have revealed results showing a comparison of DSSC performance under low light when the TiO ₂ layer structure and thickness are varied. According to these experimental data, a 3 μm TiO ₂ absorbing layer results in higher performance than a thicker layer.

Most deployed solar power and communication modules used in the market to enable sensors are the EnOcean STM110. This product contains some innovations that reduce the power consumed by the components. However, it is still only capable of powering a limited range of simple function sensors (contact, temperature and humidity) in a metered cycle. A multi-tasking sensor such as an infrared based gas or occupancy sensor or an advanced device would require higher operating power from its energy harvesting module to obtain and transmit data at a feasible rate.

Energy harvesting implementation

One method for continuously driving a device for one (several) DSSC battery is by recharging one of, for example, a rechargeable battery (alternatively, a supercapacitor or other capacitor) The storage medium is charged and the reservoir is provided with energy to the sensor unit to keep it from interrupting operation. Therefore, the two parameters are critical to the DSSC module used to drive the sensor unit: first, to allow one of the battery charges to be sufficient for the output voltage (potential difference); and second, to operate during a given period of time Enough energy produced by the device.

The device requires a certain drive potential provided by the storage medium to be available when power is required for a measurement, control or communication activity. Therefore, the energy harvesting (EH) module that charges the battery must also deliver a sufficient potential above one of the threshold potentials so that the battery is effectively charged during production. The total energy (including all churning considerations) fed into the battery reservoir must equal or exceed the energy consumed by the operation of the device. These two conditions should be met in the operating environment, which becomes critical when the device is required to operate in a dim light.

A single DSSC battery provides 0.4V to 0.75V of power depending on the light intensity. The power input of a typical sensor device has a range of 3V to 5V so that the battery reservoir is required to be charged at a similar level. In the present invention, we have introduced three methods for a DSSC EH module to provide the required voltage and power output for an indoor sensor application. The first method is "including one of a plurality of batteries connected in series", and the second method is "including a module having a large-sized single cell having a voltage boosted to a fixed potential", and a third The method is "including a module having a large-sized single cell having one of the output voltages boosted to a variable potential".

DSSC module including multiple batteries connected in series

The first solution is to use a module consisting of multiple cells connected in series such that the DSSC output voltage is multiplied. This method is widely used in the solar cell industry. However, this method has the disadvantage that the series cells must first be physically separated and then connected through the interconnect. Separation and interconnection areas cannot produce optical power and are therefore referred to as "dead zones" or "inactive zones." All of the PV modules interconnected by the series battery encounter the same dilemma: no matter what the undesired loss of the power generation area, the dead zone cannot be avoided. In the case of a module area where the device is designed to be fixed, it is usually reduced by minimizing the number of interconnected batteries. The dead zone optimizes the module design according to the highest possible efficiency. In an interconnected DSSC module, the loss due to deadband can vary from 10% to 40% depending on the number of batteries, and module size, geometry, structure, and manufacturing procedures.

A DSSC module including a large-sized single cell having an output voltage boosted to a fixed potential

The second method is to construct a power harvesting power source with a fixed output voltage using a large-size single-cell DSSC module. A module made of a large battery of this type does not require an inter-cell connection, which results in no loss of the active area. However, this design only produces a single cell output voltage that is typically insufficient to charge a battery. However, this problem can be solved by using a booster external to the DSSC module to boost the output voltage. A booster can convert up to 92% of the total power, depending on operating conditions. Therefore, the power loss due to voltage boosting is between 8% and 20%. The unit cell modules produced can be as small as 1 cm ² up to as large as possible. Since the device operates in low light and therefore has a low current, the sheet resistance does not limit the individual battery area as in the case of conventional solar modules. However, the power generated from a 1 cm ² area is too small for any useful application at present. Therefore, both useful applications and manufacturing feasibility are considered. If the light is dark, the practical size falls between 2 cm x 2 cm (or 4 cm ² equivalent area) to a maximum of 50 cm x 50 cm (or 2500 cm ² equivalent area). Since the power loss due to the sheet resistance is I ² * R, where I represents current and R represents sheet resistance. In a dim light, the current is low enough that power loss is negligible. One of the proposed square shapes is merely for ease of description. In fact, any battery of any shape, such as a rectangle with an aspect ratio below ten (10), will also work. The aspect ratio is defined herein as the ratio of its length divided by its width. Thus, the cell module of this size in the range from 4cm ² to 2500cm ² area.

Since it is not constrained by a square or rectangular shape, DSSC with one of the boost voltages has high flexibility when designing the shape. Since there is only one battery, there is no need to worry about matching the battery size to maintain equal current flow through each battery. For example, in a device having one of the screens made by e-paper ^® , LCD or other display technology, even when the width is narrow, the boundary still represents a considerable area and can be expected to be used for light energy harvesting. For this narrow but large boundary area, it is not possible to manufacture a series-connected multi-cell module for energy harvesting in a space-efficient or technically feasible manner. A single cell DSSC (which conforms to the boundary form of the display) with a voltage boosted to the supply requirements of the device can be used as an excellent energy harvester. As another example, a large size DSSC having a fixed boost output voltage can be very useful as a central energy harvester to supply energy to multiple storage media or directly to a localized region (such as in a greenhouse). Multiple energy and environmental control devices.

A DSSC module including a large-sized single cell having an output voltage boosted to a variable potential

One of the advantages of a booster is that the output potential can be varied within a certain range (for example, the Texas Instruments bq25504 "Ultra Low Power Boost Converter" has an output between 2.5V and 5.25V). This gives a good flexibility to its application. Devices made by different manufacturers have voltage inputs of different specifications. A single cell DSSC module having a voltage boosted to a variable range can supply the storage medium and device with a variable voltage input requirement within the range. This simplifies the power management design of the device and significantly saves R&D and manufacturing costs.

Embodiment 1 (including a DSSC module of a plurality of batteries connected in series)

As shown in a schematic diagram of FIG. 6, a DSSC module is made up of a plurality of batteries connected in series. A detailed view of the device is shown in FIG. The available space of the battery area is 6 cm x 6 cm or 36 cm ² . Portions of this space are used for interconnections and therefore cannot be used to generate power. In this embodiment, each DSSC cell produces at least 0.5 V at a 200 lux light intensity from a fluorescent source. There are eight batteries connected in series, and therefore, the total voltage output (open circuit voltage) is 4.0 V or higher. This is sufficient to charge a battery or alternative storage medium of a 3.0V to 3.5V rated voltage and thereby drive the connected sensor unit. A linear, buck or boost rectifier circuit, an overvoltage/undervoltage protection circuit, and a shunt charging circuit may be included between the DSSC module and the storage medium.

In the light range of 50 lux to 10,000 lux, the output power of the DSSC module is roughly proportional to the total active (power generation) area. One of the modules in this design has a typical active area of 27 cm ² and the power loss due to the dead zone in the interconnect on the module is 25%. For example, a DSSC produces 6.4 μW/cm ^{2 of} output power under a 200 lux fluorescent lamp, achieving a total output power of 172 μW. This output power and voltage is sufficient to drive a sensor unit in constant operation.

Embodiment 2 (including a DSSC module having a large-sized single cell having a fixed boost voltage output)

This second embodiment describes a module having the same usable battery area (6 cm x 6 cm) as in Embodiment 1 and under the same light condition (200 lux fluorescence). Fig. 8 is a schematic circuit diagram, and Fig. 9 is a plan view showing a device of a 6 cm x 6 cm DSSC unit. With a 0.5V output voltage, it produces 230μW of output power. The DSSC output voltage can be converted to any value from 2.5V to 5.25V by using a booster (eg, Texas Instruments bq25504 "Ultra Low Power Boost Converter") to enable charging of a wide range of storage batteries. The bq25504 has a conversion efficiency of 80% (under a 200 lux fluorescent lamp) and can reach 92% at higher light intensities. After boosting the voltage, the EH module thus produces a net output power of 184 μW. The net output power is still slightly higher than the power generated by the series interconnect module of Example 1 (which produces 172 μW).

In the present invention, although a battery for an energy storage medium has been described, it should be understood that in most cases, other types of energy storage media (eg, a conventional or super capacitor) may be used as an alternative and provide the same functionality, Although they are not explicitly mentioned in the description.

Claims (47)

An indoor system comprising: an electronic control unit; a rechargeable energy storage medium configured to provide electrical power to other components of the indoor system; and an energy harvesting module configured to generate The electrical power used to charge the rechargeable storage medium. The indoor system of claim 1, wherein the energy harvesting module comprises a dye sensitized solar cell (DSSC) module. The indoor system of claim 2, wherein the DSSC module comprises a nanocrystalline high energy band gap semiconductor metal oxide between a substrate and a porous scattering layer of a nanocrystalline high energy band gap semiconductor metal oxide particle. One of the particles of the porous absorbing layer, wherein the porous absorbing layer has a thickness of at most 7 μm. The indoor system of claim 3, wherein the porous absorbent layer has a thickness of at least 1.5 μm. The indoor system of claim 3 or 4, wherein the porous scattering layer has a thickness of at least 6 μm and/or at most 8 μm. The indoor system of any one of claims 3 to 5, wherein the TiO ₂ particles of the porous scattering layer generally have a diameter larger than a diameter of the TiO ₂ particles of the porous absorbing layer. The indoor system of any one of claims 2 to 6, wherein: the DSSC module includes a single DSSC battery configured to output a voltage; and the energy harvesting module includes a configuration to enable the single DSSC battery The voltage output is boosted to produce a booster that is one of sufficient potential differences for efficient charging of the rechargeable energy storage medium. The indoor system of claim 7, wherein the output voltage is fixed after the boost conversion. The indoor system of claim 7, wherein the output voltage is variable after boost conversion. The indoor system of any one of claims 7 to 9, wherein the single DSSC battery has a substantially square shape. The indoor system of any one of claims 7 to 9, wherein the single DSSC battery has a substantially rectangular shape having a width to height ratio of less than one. The indoor system of any one of claims 7 to 9, wherein the single DSSC battery has an irregular shape. The requested item 7 to 12 of a chamber system, wherein the single one of the DSSC having a total plane area in the range of about 4cm ² to from about 2500cm ^2. The indoor system of any one of claims 2 to 6, wherein the DSSC module comprises a plurality of DSSC batteries connected in series. The indoor system of claim 14, wherein the DSSC module is configured to charge the energy storage medium without voltage boosting. The indoor system of claim 14, wherein the energy harvesting module includes a booster configured to boost a voltage output of the DSSC module such that the DSSC module passes the booster The energy storage medium is indirectly charged. The indoor system of any one of claims 14 to 16, wherein the DSSC module comprises at least two DSSC batteries connected in series. The indoor system of any one of claims 7 to 17, wherein the DSSC battery or each DSSC battery of the DSSC module comprises: a working electrode; a counter electrode; and an electrolyte filled in the working electrode and the counter Between the electrodes. The indoor system of claim 18, wherein the working electrode comprises a nanoparticle of a nanocrystalline high energy band gap semiconductor metal oxide, wherein the metal oxide optionally comprises TiO ₂ . The indoor system of any one of claims 18 to 19, wherein the working electrode adsorbs a dye. The indoor system of any one of claims 18 to 20, wherein the counter electrode comprises a catalyst layer coated with platinum or carbon. An indoor system according to any one of the preceding claims, wherein the energy harvesting module delivers at least 2.0 μW/cm ² of light intensity increment per 100 lux in a range of input light intensities from 50 lux to 10,000 lux of a fluorescent or LED lamp. A power density. An indoor system according to any of the preceding claims, which is designed and optimized according to room light and scattered light, in particular according to visible spectrum light having a wavelength from about 400 nm to about 800 nm. An indoor system according to any of the preceding claims, comprising: one or more functional units. The indoor system of claim 24, wherein one of the functional units comprises one or more of a sensing unit, a visual display, an actuator, and an audio device. The indoor system of claim 25, wherein the sensing unit is configured to sense at least one parameter of the indoor environment. The indoor system of claim 25, wherein the sensing unit comprises a single sensing head configured to sense a single parameter. The indoor system of claim 25, wherein the sensing unit comprises a plurality of sensing heads each configured to sense a single parameter. The indoor system of claim 25, wherein the sensing unit comprises a single sensing head configured to sense one of a plurality of parameters. The indoor system of claim 25, wherein the sensing unit comprises a plurality of sensing heads each configured to sense a plurality of parameters. An indoor system according to any of the preceding claims, comprising: a wireless communication transceiver. The indoor system of any of the preceding claims, wherein the rechargeable energy storage medium is a rechargeable battery or a supercapacitor. An indoor system according to any of the preceding claims, wherein the system has the use of increasing energy use efficiency. An indoor system according to any of the preceding claims, wherein the system has the purpose of monitoring environmental parameters to enhance the building comfort of the building occupants. An indoor system according to any of the preceding claims, wherein the system has the use of monitoring environmental parameters to produce a controlled horticultural environment. An indoor system according to any of the preceding claims, wherein the system is an indoor sensing and control system. A method of manufacturing an indoor system, the indoor system comprising: an electronic control unit; a rechargeable energy storage medium configured to provide electrical power to other components of the indoor system; and an energy harvesting module, It is configured to generate electrical power for charging the rechargeable storage medium. The method of claim 37, wherein the substrate of the working electrode is coated with a fluorine-doped tin oxide, FTO. The method of claim 37 or 38, comprising: treating the surface of the FTO and/or one of the porous scattering layers for passivation purposes to reduce surface defects. The method of claim 39, wherein the treating comprises: immersing the surface in an aqueous solution of TiCl ₄ . The method of claim 40, wherein the concentration of TiCl _{4 in} the aqueous solution is in a range from about 20 mM to about 60 mM. The method of any one of claims 40 to 41, wherein the temperature of the TiCl ₄ aqueous solution is in the range of from about 45 ° C to about 80 ° C. The method of any one of claims 40 to 42, wherein the immersion time is in the range of from about 15 minutes to about 45 minutes. The method of any one of claims 39 to 43, wherein the processing further comprises: using an air sintering process of a combustion furnace. The method of claim 44, wherein the furnace has a temperature in a range from about 400 ° C to about 550 ° C. The method of claim 44 or 45, wherein the sintering time maintained at the highest temperature is in the range of from about 15 minutes to about 90 minutes. The method of any one of claims 37 to 46, wherein the indoor system has the features of any one of claims 2 to 36.