Hybrid energy storage system, renewable energy system including the storage system, and method of using same

Abstract

This disclosure generally relates to stabilizing energy provided by an energy source, and more particularly to systems and methods for using multiple types of energy storage devices to selectively capture and provide energy. An energy source provides energy, and the energy storage devices selectively capture energy provided by the energy source in excess of an immediate energy requirement of a load and selectively provide energy when the immediate energy requirement of the load exceeds the energy provided by the energy source.

What is claimed: 
     
       1. A method of stabilizing power provided by an energy source to a load, the method comprising:
 capturing, in a first energy storage device, energy produced by the energy source in excess of an immediate energy requirement of the load unless an energy level of the first energy storage device is at a first maximum threshold; 
 capturing, in a second energy storage device, the energy produced by the energy source in excess of the immediate energy requirement of the load if the energy level of the first energy storage device is at the first maximum threshold, unless an energy level of the second energy storage device is at a second maximum threshold, wherein the first and the second energy storage devices are part of a hybrid energy storage system, the system comprising one or more of electrochemical cells, batteries, fuel cells, capacitors, compressed air tanks, flywheels, pumped hydro systems, flow batteries, and thermal storage systems; and 
 varying an intake rate threshold of the first energy storage device, an intake rate threshold of the second energy storage device, a discharge rate threshold of the first energy storage device, and a discharge rate threshold of the second energy storage device as a function of at least one of: a type of the energy storage device, an initial capacity of the energy storage device, a characteristic internal resistance of the energy storage device, a chemical resistance of the energy storage device, an electrolyte of the energy storage device, a temperature of the energy storage device, a state of charge of the energy storage device, a capacity loss of the energy storage device, an intake efficiency of the energy storage device, and a discharge efficiency of the energy storage device an energy requirement of the load and an energy production profile for the energy source. 
 
     
     
       2. The method of  claim 1 , further comprising:
 transferring energy from the first energy storage device to the second energy storage device in response to the energy level of the first energy storage device reaching the first maximum threshold; and 
 ceasing transferring energy from the first energy storage device to the second energy storage device in response to (i) the energy level of the first energy storage device reaching a first predetermined level, or (ii) the energy level of the second energy storage device reaching the second maximum threshold. 
 
     
     
       3. The method of  claim 1 , further comprising:
 providing energy from the first energy storage device to the load when the an immediate energy requirement of the load exceeds the energy produced by the energy source unless the energy level of the first storage device is at a first minimum threshold; and 
 providing energy from the second energy storage device to the load when the immediate energy requirement of the load exceeds the energy produced by the energy source and the energy level of the first storage device is at the first minimum threshold, unless an energy level of the second energy storage device is at a second minimum threshold. 
 
     
     
       4. The method of  claim 1 , further comprising:
 transferring energy from the second energy storage device to the first energy storage device in response to the energy level of the first energy storage device reaching a first minimum threshold; and 
 ceasing transferring energy from the second energy storage device to the first energy storage device in response to the energy level of the first energy storage device reaching a first predetermined level or the energy level of the second energy storage device reaching a second minimum threshold. 
 
     
     
       5. The method of claim  4  1, further comprising:
 transferring energy between the first energy storage device and the second energy storage device at a predetermined time interval, the transferring including said transferring comprising:
 providing energy from the first energy storage device to the second energy storage device if the energy level of the first energy storage device is greater than the first predetermined level; 
 providing energy from the second energy storage device to the first energy storage device if the energy level of the first energy storage device is less than the first predetermined level; and 
 ceasing providing energy from the first energy storage device to the second energy storage device or from the second energy storage device to the first energy storage device when the energy level of the first energy storage device reaches the first predetermined level or the energy level of the second storage device reaches the second minimum threshold or the second maximum threshold. 
 
 
     
     
       6. The method of  claim 1 , further comprising:
 varying a first predetermined level of the first energy storage device and a second predetermined level of the second energy storage device as a function of an energy requirement profile of the load; 
 varying the first predetermined level of the first energy storage device and the second predetermined level of the second energy storage device as a function of an energy output profile of the energy source; and 
 preventing capture of energy in at least one of the first and second energy storage devices as a function of at least one of: the a temperature of the energy storage device, a reduced storage or discharge efficiency of the energy storage device, a diminished capacity of the energy storage device, a number of cycles of the energy storage device, and a strain of the energy storage device. 
 
     
     
       7. The method of  claim 1 , wherein
 the capturing, in the first energy storage device, of energy produced by the energy source in excess of the immediate energy requirement of the load further includes capturing energy in the first energy storage device in excess of the an immediate energy requirement of the load up to an intake rate threshold of the energy source, and 
 the capturing, in the second energy storage device, of energy produced by the energy source in excess of the immediate energy requirement of the load further includes capturing energy in the second energy storage device in excess of the sum of the immediate energy requirement of the load and the intake rate threshold of the first energy source. 
 
     
     
       8. The method of  claim 1 , further comprising:
 providing energy from the first energy storage device to the load when the an immediate energy requirement of the load exceeds the energy produced by the energy source up to a discharge rate threshold of the first energy storage device; and 
 providing energy from the second energy storage device to the load when the immediate energy requirement of the load exceeds the sum of the energy produced by the energy source and the discharge rate threshold of the first energy storage device up to a discharge rate threshold of the second energy storage device. 
 
     
     
       9. A system for providing power to a load, the system comprising:
 an energy source configured to provide power; 
 a first energy storage device configured to selectively capture power from the energy source and selectively provide the captured power to the load; 
 a second energy storage device configured to selectively capture power from the energy source and selectively provide captured power to the load, wherein the first and the second energy storage devices are part of a hybrid energy storage system, the system comprising one or more of electrochemical cells, batteries, fuel cells, capacitors, compressed air tanks, flywheels, pumped hydro systems, flow batteries, and thermal storage systems; and 
 an energy flow controller including a power monitor configured to: (i) monitor a difference between the power provided by the energy source and an immediate energy requirement of the load, and (ii) produce a power signal indicative of the monitored difference, based on an energy requirement of the load and an energy production profile for the energy source; 
 a first energy level monitor configured to monitor an energy level of the first energy storage device and provide a first energy level signal indicative of the energy level of the first energy storage device, 
 a second energy level monitor configured to monitor an energy level of the second energy storage device and provide a second energy level signal indicative of the energy level of the second energy storage device, 
 an energy converter configured to respond to a capture signal for converting power from the energy source into power for at least one of the first and second energy storage devices and; 
 a switch signal for directing the converted power to at least one of the first energy storage device and the second energy storage device,; and
 a controller configured to (i) receive the power signal, the first energy level signal, and the second energy level signal, and (ii) determine from the power signal that the power provided by the energy source exceeds the immediate energy requirement of the load and provide the capture signal and the switch signal to the energy converter such that the energy provided by the energy source in excess of the immediate energy requirement of the load is captured in the first energy storage device unless the first energy level signal indicates that the energy level of the first energy storage device is at a first maximum threshold whereupon the controller alters the switch signal such that the energy converter directs the energy in excess of the immediate energy requirement of the load to the second energy storage device unless the second energy level signal indicates that the energy level of the second energy storage device is at a second maximum threshold. 
 
 
     
     
       10. The system of  claim 9 , wherein
 the energy converter includes (i) a rectifier configured to convert power from the energy source into energy for storage in at least one of the first energy storage device and the second energy storage device, and (ii) an inverter configured to convert energy from at least one of the first energy storage device and the second energy storage device into power for the load. 
 
     
     
       11. The system of  claim 9 , wherein the energy converter is further configured to respond to a first transfer signal from the controller for transferring energy from the first energy storage device to the second energy storage device, and the controller is further configured to (iii) provide the first transfer signal when the first energy level signal indicates that the energy level of the first energy storage device has reached the first maximum threshold, and (iv) cease providing the first transfer signal in response to the first energy level signal indicating that when the energy level of the first energy storage device has reached a first predetermined level or the second energy level signal indicating that the energy level of the second energy storage device has reached the second maximum threshold. 
     
     
       12. The system of  claim 9 , wherein the energy converter is further configured to respond to a discharge signal for converting energy from at least one of the first and second energy storage devices into power for the load and a second switch signal for determining which of the first and second energy storage devices to convert the energy from, and wherein the controller is further configured to provide the discharge signal and the second switch signal to the energy converter when the power signal indicates that the immediate energy requirement of the load exceeds the energy produced by the energy source such that the energy is provided from the first energy storage device unless the first energy level signal indicates that the energy level of the first storage device is at a first minimum threshold whereupon the controller alters the switch signal such that the energy converter converts energy from the second energy storage device for the load, unless the second energy level signal indicates that the energy level of the second energy storage device is at a second minimum threshold. 
     
     
       13. The system of claim  12  9, wherein the energy converter is further responsive to a second transfer signal for transferring energy from the second energy storage device to the first energy storage device, and the controller is further configured to (iii) provide the second transfer signal to the energy converter in response to the first energy level signal indicating that when the energy level of the first energy storage device has reached the first minimum threshold, and (iv) cease providing the second transfer signal to the energy converter in response to the first energy level signal indicating that when the energy level of the first energy storage device has reached a first predetermined level or the second energy level signal indicating that the energy level of the second energy storage device has reached the second minimum threshold. 
     
     
       14. The system of claim  13  9, wherein
 the controller is further configured to (iii) selectively provide one of the first transfer signal and the second transfer signal to the energy converter at a predetermined time interval, (iv) provide the first energy transfer signal if the first energy level signal indicates that energy level of the first energy storage device is greater than the first predetermined level, (v) provide the second energy transfer signal if the second energy level signal indicates that the energy level of the first energy storage device is less than the first predetermined level, and (vi) cease providing the first energy transfer signal or the second energy transfer signal when the first energy level signal indicates that the energy level of the first energy storage device has reached the first predetermined level or the second energy level signal indicates that the energy level of the second storage device has reached the second minimum threshold or the second maximum threshold. 
 
     
     
       15. The system of  claim 9 , wherein the controller is further configured to (iii) vary a first predetermined level of the first energy storage device and a second predetermined level of the second energy storage device as a function of an energy requirement profile of the load, (iv) vary the first predetermined level of the first energy storage device and the second predetermined level of the second energy storage device as a function of and an energy output profile of the energy source, and (v) (iv) prevent capture of energy in at least one of the first and second energy storage devices as a function of at least one of a temperature of the energy storage device, a reduced storage or discharge efficiency of the energy storage device, a diminished capacity of the energy storage device, a number of cycles of the energy storage device, and a strain of the energy storage device. 
     
     
       16. The system of  claim 9 , wherein
 the energy flow controller is configured to capture energy in the first energy storage device produced by the energy source in excess of the immediate energy requirement of the load up to an intake rate threshold of the first energy storage device, and to capture energy in the second energy storage device produced by the energy source in excess of the sum of the immediate energy requirement of the load and the intake rate threshold of the first energy storage device. 
 
     
     
       17. The system of  claim 9 , wherein
 the energy flow controller is configured to provide energy from the first energy storage device to the load when the immediate energy requirement of the load exceeds the energy produced by the energy source up to a discharge rate threshold of the first energy storage device, and to provide energy from the second energy storage device to the load when the immediate energy requirement of the load exceeds the sum of the energy produced by the energy source and the discharge rate threshold of the first energy storage device up to a discharge rate threshold of the second energy storage device. 
 
     
     
       18. A method of stabilizing power provided by an energy source to a load, the method comprising:
 capturing, in a first energy storage device, energy produced by the energy source in excess of an immediate energy requirement of the load up to an intake rate threshold of the first energy storage device; 
 capturing, in a second energy storage device, energy produced by the energy source in excess of the sum of the immediate energy requirement of the load and the intake rate threshold of the first energy storage device wherein the first and the second energy storage devices are part of a hybrid energy storage system, the system comprising one or more of electrochemical cells, batteries, fuel cells, capacitors, compressed air tanks, flywheels, pumped hydro systems, flow batteries, and thermal storage systems; and 
 varying an intake rate threshold of the first energy storage device, an intake rate threshold of the second energy storage device, a discharge rate threshold of the first energy storage device, and a discharge rate threshold of the second energy storage device as a function of at least one of: a type of the energy storage device, an initial capacity of the energy storage device, a characteristic internal resistance of the energy storage device, a chemical resistance of the energy storage device, an electrolyte of the energy storage device, a temperature of the energy storage device, and a state of charge of the energy storage device, a capacity loss of the energy storage device, an intake efficiency of the energy storage device, and a discharge efficiency of the energy storage device. 
 
     
     
       19. The method of  claim 18 , further comprising:
 providing energy from the first energy storage device to the load when the immediate energy requirement of the load exceeds the energy produced by the energy source up to the discharge rate threshold of the first energy storage device; and 
 providing energy from the second energy storage device to the load when the immediate energy requirement of the load exceeds the sum of the energy produced by the energy source and the discharge rate threshold of the first energy storage device up to the discharge rate threshold of the second energy storage device,. 
 
     
     
       20. The method of  claim 18 , further comprising:
 varying the intake rate threshold of the first energy storage device, the intake rate threshold of the second energy storage device, the discharge rate threshold of the first energy storage device, and the discharge rate threshold of the second energy storage device further as a function of at least one of: a cooling capacity of the energy storage device, a heat dissipation coefficient of the energy storage device, an ambient air temperature profile, an energy requirement of the load, an initial capacity of the energy storage device, a characteristic internal resistance of the energy storage device, a chemical resistance of the energy storage device, an electrolyte of the energy storage device, a temperature of the energy storage device, a capacity loss of the energy storage device, an intake efficiency of the energy storage device, and a discharge efficiency of the energy storage device, and a cycle rate profile, and an energy production profile for the energy source. 
 
     
     
       21. A system for providing energy to a load, the system comprising:
 an energy source;   a first storage device that stores energy;   a second storage device that stores energy, wherein the first and the second energy storage devices are part of a hybrid energy storage system, the system comprising one or more of electrochemical cells, batteries, fuel cells, capacitors, compressed air tanks, flywheels, pumped hydro systems, flow batteries, and thermal storage systems;   a controller for monitoring energy requirements of the load, conditions of the first storage device, and conditions of the second storage device, wherein
 energy is transmitted from the energy source to the load under the condition that the energy source meets the requirements of the load, and/or 
 energy is transmitted from at least one of the first storage device and the second storage device to the load under the condition that the energy source is not available, energy being transmitted from at least one of the first storage device and the second device based on the monitored conditions of each of the first storage device and the second storage device, and 
   the controller is further configured to vary an intake rate threshold of the first energy storage device, an intake rate threshold of the second energy storage device, a discharge rate threshold of the first energy storage device, and a discharge rate threshold of the second energy storage device as a function of at least one of: an energy requirement of the load and an energy production profile for the energy source.   
     
     
       22. The system of claim 21 wherein the controller determines whether to transmit energy from the first storage device to the second storage device based on at least one of charge and/or discharge capabilities of the first and second storage devices, type of energy demand, energy requirement, and/or state of charge of the first and second storage devices. 
     
     
       23. The system of claim 21 wherein each of the first storage device and the second storage device is comprised of a plurality of storage devices. 
     
     
       24. The system of claim 23 wherein each of the plurality of storage devices of the first storage device has different charge and/or discharge capabilities than each of the plurality of storage devices of the second storage device. 
     
     
       25. A device for stabilizing energy provided to a load from an energy source, the device comprising:
 a first storage device configured to provide energy to the load and to draw energy from the energy source;   a second storage device configured to provide energy to the load and to draw energy from the energy source, wherein the first and the second energy storage devices are part of a hybrid energy storage system, the system comprising one or more of electrochemical cells, batteries, fuel cells, capacitors, compressed air tanks, flywheels, pumped hydro systems, flow batteries, and thermal storage systems;   a sensor that determines an energy requirement of the load, wherein
 the first storage device provides energy to the load under the condition that the energy requirement of the load exceeds the energy provided by the energy source, and 
 the second storage device provides energy to the load under the condition that the energy requirement of the load exceeds the energy provided by the energy source; and 
   a controller configured to vary an intake rate threshold of the first energy storage device, an intake rate threshold of the second energy storage device, a discharge rate threshold of the first energy storage device, and a discharge rate threshold of the second energy storage device as a function of at least one of: an energy requirement of the load, and an energy production profile for the energy source.