# US 10,319,870 B2 · Photovoltaic module with a controllable infrared protection layer

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- Number: US 10,319,870 B2
- Document ID: US10319870B2
- Status: Granted
- Kind: B2
- Application number: 12/887,156
- Filed: 2010-09-21
- Published: 2011-05-05
- Granted: 2019-06-11
- Earliest claimed: 2009-11-02
- Assignees: International Business Machines Corporation
- Applicants: Lawrence A. Clevenger; Timothy J. Dalton; Maxime Darnon; Rainer Krause; Gerd Pfeiffer; Kevin Prettyman; Carl J. Radens; Brian C. Sapp
- Inventors: Lawrence A. Clevenger; Timothy J. Dalton; Maxime Darnon; Rainer Krause; Gerd Pfeiffer; Kevin Prettyman; Carl J. Radens; Brian C. Sapp
- Web page: https://patentgrep.com/patent/US10319870B2

## CPC

- H10F 77/492: {Spectrum-splitting means, e.g. dichroic mirrors}
- G02B 26/007: {the movable or deformable optical element controlling the colour, i.e. a spectral characteristic, of the light}
- H10F 19/80: Encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells
- H10F 19/807: {Double-glass encapsulation, e.g. photovoltaic cells arranged between front and rear glass sheets}
- H10F 19/85: Protective back sheets
- Y02E 10/52: PV systems with concentrators
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

An apparatus, system, and method are disclosed for a photovoltaic module, the photovoltaic module comprising a plurality of photovoltaic cells, a controllable infrared protection layer, and a protection switching means. The controllable infrared protection layer is for reducing the infrared radiation absorbed by the photovoltaic module, where the controllable infrared protection layer has a first state and a second state. When the infrared protection layer is in the first state the transmission of infrared radiation to the photovoltaic cells is higher than when the infrared protection layer is in the second state. The protection switching means is for switching the controllable infrared protection layer between the first state and the second state.

## Claims

### Claim 1

A photovoltaic module comprising:
a plurality of photovoltaic cells, wherein the photovoltaic module has a front side and a back side, the plurality of photovoltaic cells producing electricity when the front side of the photovoltaic module is illuminated;
a glass substrate coupled to the front side of the photovoltaic module;
a controllable infrared protection layer for reducing the infrared radiation absorbed by the photovoltaic module, wherein the controllable infrared protection layer has a first state and a second state, wherein when the infrared protection layer is in the first state the transmission of infrared radiation to the photovoltaic cells is higher than when the infrared protection layer is in the second state, the controllable infrared protection layer comprising a polymer layer with reflective liquid crystals, the polymer layer comprising a top electrode and a bottom electrode, wherein one of the top electrode and the bottom electrode is adjacent to the glass substrate, wherein the polymer layer is in the first state when the top electrode and the bottom electrode are at the same potential and the polymer layer is in the second state when a switching voltage is applied across the top electrode and the bottom electrode, wherein light of the visible wavelength travels through the polymer layer and the glass substrate to reach the plurality of photovoltaic cells in the first state and in the second state;
a protection switching means for switching the controllable infrared protection layer between the first state and the second state, the protection switching means comprising a voltage supply adapted for applying a switching voltage to the top electrode and the bottom electrode.

### Claim 2 (depends on 1)

The photovoltaic module of claim 1, wherein the polymer layer with reflective liquid crystals comprises cholesteric liquid crystals.

### Claim 3 (depends on 1)

The photovoltaic module of claim 1, wherein the controllable infrared protection layer comprises an ultraviolet reflector, the ultraviolet reflector reflecting ultraviolet radiation in the first state and the second state.

### Claim 4 (depends on 3)

The photovoltaic module of claim 3, wherein the ultraviolet reflector comprises one or more of acetone (AcAc) chelated silane, 3-glycidoxypropyl-trimethoxysilane (GPTMS) modified nano-titania sol, methacrylate functionalized silane, and nanoscaled boehmite particles.

### Claim 5 (depends on 1)

The photovoltaic module of claim 1, wherein the photovoltaic module further comprise a temperature sensor, the temperature sensor measuring a module temperature representative of the temperature of the plurality of photovoltaic cells, and wherein the protection switching means is adapted for switching the controllable infrared protection layer from the first state to the second state when the module temperature exceeds a predetermined temperature threshold.

### Claim 6 (depends on 1)

The photovoltaic module of claim 1, wherein the protection switching means comprises a thermal expansion element, wherein the temperature of the thermal expansion element switches the controllable infrared protection layer between the first state and the second state.

### Claim 7

A photovoltaic module system, the photovoltaic module system comprising:
a photovoltaic module comprising:
a plurality of photovoltaic cells, wherein the photovoltaic module has a front side and a back side, the plurality of photovoltaic cells producing electricity when the front side of the photovoltaic module is illuminated;
a glass substrate coupled to the front side of the photovoltaic module;
a controllable infrared protection layer for reducing the infrared radiation absorbed by the photovoltaic module, wherein the controllable infrared protection layer has a first state and a second state, wherein when the infrared protection layer is in the first state the transmission of infrared radiation to the photovoltaic cells is higher than when the infrared protection layer is in the second state, the controllable infrared protection layer comprising a polymer layer with reflective liquid crystals, the polymer layer comprising a top electrode and a bottom electrode, wherein one of the top electrode and the bottom electrode is adjacent to the glass substrate, wherein the polymer layer is in the first state when the top electrode and the bottom electrode are at the same potential and the polymer layer is in the second state when a switching voltage is applied across the top electrode and the bottom electrode, wherein light of the visible wavelength travels through the polymer layer and the glass substrate to reach the plurality of photovoltaic cells in the first state and in the second state; and
a protection switching means for switching the controllable infrared protection layer between the first state and the second state, the protection switching means comprising a voltage supply adapted for applying a switching voltage to the top electrode and the bottom electrode;
a temperature sensor for measuring a photovoltaic module temperature representative of the temperature of the plurality of photovoltaic cells; and
a control system adapted for:
receiving the photovoltaic module temperature measurement;
signaling the protection switching means when the photovoltaic module temperature measurement exceeds a predetermined threshold; and
switching the controllable infrared protection layer from the first state to the second state in response to receiving a signal indicating that the photovoltaic module temperature measurement exceeds a predetermined threshold.

### Claim 8

A computer program product for execution by a control system for controlling a photovoltaic module system, the photovoltaic module system comprising
a photovoltaic module comprising:
a plurality of photovoltaic cells, wherein the photovoltaic module has a front side and a back side, the plurality of photovoltaic cells producing electricity when the front side of the photovoltaic module is illuminated;
a glass substrate coupled to the front side of the photovoltaic module;
a controllable infrared protection layer for reducing the infrared radiation absorbed by the photovoltaic module, wherein the controllable infrared protection layer has a first state and a second state, wherein when the infrared protection layer is in the first state the transmission of infrared radiation to the photovoltaic cells is higher than when the infrared protection layer is in the second state, the controllable infrared protection layer comprising a polymer layer with reflective liquid crystals, the polymer layer comprising a top electrode and a bottom electrode, wherein one of the top electrode and the bottom electrode is adjacent to the glass substrate, wherein the polymer layer is in the first state when the top electrode and the bottom electrode are at the same potential and the polymer layer is in the second state when a switching voltage is applied across the top electrode and the bottom electrode, wherein light of the visible wavelength travels through the polymer layer and the glass substrate to reach the plurality of photovoltaic cells in the first state and in the second state; and
a protection switching means for switching the controllable infrared protection layer between the first state and the second state; and
a temperature sensor for measuring a photovoltaic module temperature representative of the temperature of the plurality of photovoltaic cells,
the computer program product comprising machine executable instructions for performing the steps of:
monitoring the photovoltaic module temperature;
determining if the photovoltaic module temperature measurement exceeds a predetermined threshold;
signaling the protection switching means when the photovoltaic module temperature measurement exceeds a predetermined temperature threshold;
monitoring the production of electricity by the photovoltaic module;
calculating a maintenance schedule based on the measurement of the production of electricity and of temperature to determine performance of the photovoltaic module; and
sending a message that maintenance is requested in response to determining that performance of the photovoltaic module has decreased below a predetermined level.

### Claim 9

A method for operating a photovoltaic module system, wherein the method comprising:
monitoring temperature of a photovoltaic module, the photovoltaic module comprising
a plurality of photovoltaic cells, wherein the photovoltaic module has a front side and a back side, the plurality of photovoltaic cells producing electricity when the front side of the photovoltaic module is illuminated;
a glass substrate coupled to the front side of the photovoltaic module;
a controllable infrared protection layer for reducing the infrared radiation absorbed by the photovoltaic module, wherein the controllable infrared protection layer has a first state and a second state, wherein when the infrared protection layer is in the first state the transmission of infrared radiation to the photovoltaic cells is higher than when the infrared protection layer is in the second state, the controllable infrared protection layer comprising a polymer layer with reflective liquid crystals, the polymer layer comprising a top electrode and a bottom electrode, wherein one of the top electrode and the bottom electrode is adjacent to the glass substrate, wherein the polymer layer is in the first state when the top electrode and the bottom electrode are at the same potential and the polymer layer is in the second state when a switching voltage is applied across the top electrode and the bottom electrode, wherein light of the visible wavelength travels through the polymer layer and the glass substrate to reach the plurality of photovoltaic cells in the first state and in the second state; and
a protection switching means for switching the controllable infrared protection layer between the first state and the second state, the protection switching means comprising a voltage supply adapted for applying a switching voltage to the top electrode and the bottom electrode;
determining if the photovoltaic module temperature measurement exceeds a predetermined temperature threshold; and
signaling the protection switching means when the photovoltaic module temperature measurement exceeds the predetermined temperature threshold;
monitoring the production of electricity by the photovoltaic module;
calculating a maintenance schedule based on the measurement of the production of electricity and of temperature to determine performance of the photovoltaic module; and
sending a message that maintenance is requested in response to determining that performance of the photovoltaic module has decreased below a predetermined level.