Method and apparatus for integrated electric electric power generation, storage, and supply distributed and networked at the same time

Abstract

An electric power retention distribution cell apparatus and method of operation of the cell includes a rechargeable battery assembly, a bi-directional inverter and a switch control operatively connectable to an electric utility grid, an outside power charging supply and at least one end user wherein the cell is selectively switched between the electric utility grid and the battery assembly to supply electric power to the one or more end users. The cell is connected to the power charging supply for charging the battery assembly, and for dividing the battery assembly into groups of batteries for storage at a lower terminal output voltages of each group than the battery assembly output voltage when in use as the primary power supply. Electric power supply networks are also described for a utility hub network formed using two or more cells, and for a regional utility hub network formed using multiple utility hubs.

Claims

1. A cost effective and resilient power system comprising: a) an electric utility power grid configured to supply electric grid energy; b) residential and commercial end users said residential and commercial users being connected to said electric utility power grid; c) at least one electric power retention distribution cell serving as a back-up power system, wherein said at least one electric power retention distribution cell comprises: i) at least one rechargeable battery assembly comprising at least one group of said rechargeable batteries, each of said at least one group of said rechargeable batteries comprising an optimal number of batteries grouped together to optimize retention of energy within each said at least one rechargeable battery assembly the optimal number of batteries being the maximum number of batteries connected serially while retaining energy over a period of time in the same manner as a single battery; ii) at least one bi-directional inverter connected to the rechargeable battery assembly, said bi-directional inverter configured for: A) inverting a first DC voltage from a first battery group and a second battery group to a first AC voltage of the electric utility grid; B) inverting a second DC voltage from the first battery group and the second battery group to a second AC voltage for delivery to the load; and C) inverting the first AC voltage from the electric utility grid to the first DC voltage to the first and second battery groups; iii. a plurality of switches having the ability to automatically and/or manually switch between modes based on system status, said plurality of switches in communication with said at least one bi-directional inverter, said modes selected from the group consisting of a charging mode; a retention mode; a supplying energy mode and combinations thereof; iv. a switch control system operably connected to the bi-directional inverter, to an electric utility grid, to a power charging supply, to said plurality of switch, and to at least one end user, said switch control system controlled by a programmable computer or at least one programmable microprocessor; d) a plurality of clusters, each of said clusters formed by a plurality said electric power retention distribution cells; e) an energy network, said energy network formed by said plurality of clusters, wherein said electrical grid integrates said cells into clusters and said wherein the switch control system is configured to selectively switch between the electric utility grid and the battery assembly of the electric power retention distribution cell as the primary electric power supply to the at least one end user; f) a renewable energy generation system, said renewable energy system to connected to said rechargeable battery based energy storage system, said system having the ability to provide power to the end user, said regeneration energy generation system is a regenerative power generator selected from the group consisting of a solar power generator, a wind power generator, and a geothermal power generator, wherein in case of equipment failure or battery depletion, the control switch system connects the grid to the residence or commercial entity and restores regular grid power supply to the end user by closing of a power grid switch, and opening said battery switch and further comprising an end user energy demand sensing system, so that when said battery is charged, said energy demand sensing system sends a signal to said control system which switches the power system to said storage mode which stays in said storage mode without use of stored energy, whereupon said demand sensing system sends a signal to said control system which switches the power system to retention mode to maximize energy savings until said control system senses demand on energy use and sends a signal to said control system which switches the power system to energy supply mode.

2. The power system of claim 1, wherein said switch control system is configured to: a) allow for the connection to the electric grid energy for delivery of power to the energy storage assembly and to said end user starting at a first set time; and b) allow for the disconnection of the grid energy from the energy storage assembly and the end user, and for the connection of energy storage assembly to the end user, at a second set time.

3. The power system of claim 1, where said batteries are selected from the group consisting of new rechargeable electric automobile/vehicle batteries, used electric automobile/vehicle batteries, and 12 volt batteries.

4. The power system of claim 3, wherein the switch control system has the ability to connect the at least one electric power distribution cell to the grid by closing a battery switch.

5. The power system of claim 1, wherein said computer or microprocessor has the ability to control when the end user is connected to the electric power utility grid and when the end user is using stored electric power in the at least one electric power distribution cell.

6. The power system of claim 1, wherein said rechargeable batteries have the ability to be charged by the current selected from the group consisting of the electric power grid, alternative sources of energy, and combinations thereof.

7. The power system of claim 1, further comprising plurality of sensors, each of said sensors having the ability to sense a state of charge (SoC) and to send a signal to the power system which in turn has the ability to to switch or connect to different modes of operations or functions.

8. The power system in claim 7, wherein the control system is pre-programmed with functional modes and comprises a rechargeable battery stored energy level feedback system which allows for switching amongst said functional modes based upon readings from said SoC sensors.

9. The power system of claim 1, wherein said computer or said microprocessor has the ability to select charging times and determine whether renewable sources or the electric grid to be used for power, based upon specific criteria.

10. The power system of claim 1, wherein configurations of said batteries allow for said batteries to supply stored energy to said end user and continue recharging part of said batteries from renewable sources.

11. The power system of claim 1, wherein said computer or microprocessor allows for a change in programing functions from configuration of the batteries.

12. The battery assembly of claim 1, wherein at least one of the plurality of switches is a relay switch.

13. A power system resilient through multiple layers for residential and commercial users, said residential and commercial users being connected to said power system, said system comprising: a) a plurality of electric power retention distribution cells having the ability to store, retain, and supply energy, each of said cells comprising: i) a rechargeable battery assembly system comprising at least one rechargeable battery group, said rechargeable battery assembly system serving as a back-up power system; ii) a bi-directional inverter connected to the rechargeable battery assembly, said bi-directional inverter configured for: A) inverting a first DC voltage from a first battery group and a second battery group to a first AC voltage of the electric utility grid; and B) inverting a second DC voltage from the first battery group and the second battery group to a second AC voltage for delivery to the load; and C) inverting the first AC voltage from the electric utility grid to the first DC voltage to the first and second battery groups; iii) a plurality of switches having the ability to automatically and/or manually switch between modes based on system status, said plurality of switches in communication with said at least one bi-directional inverter, said modes selected from the group consisting of a charging mode; a retention mode; a supplying energy mode and combinations thereof; iv) a switch control system operably connected to the bi-directional inverter, to an electric utility grid, to a power charging supply and to at least one end user, said rechargeable battery assembly positional at locations of said residential and commercial users, said switch control system having a retention mode setting to preserve stored energy of said rechargeable batteries, b) an utility hub, to which said plurality of cells is attached, forming a cluster; c) a plurality of said clusters, each of said clusters formed by said plurality of said utility hubs; d) an energy network, wherein there is a two way transmission of energy to and from said plurality of clusters so that the switch control system is configured to selectively switch between the electric utility grid and the battery assembly of the electric power retention distribution cell as the primary electric power supply to the at least one end user and further comprising an end user energy demand sensing system, so that when said battery is charged, said energy demand sensing system sends a signal to said control system which switches the power system to storage mode and which stays in in storage mode without use of stored energy, whereupon said demand sensing system sends a signal to said control system which switches to the power system retention mode to maximize energy savings until said sensing system senses a demand on energy and sends a signal to said control system which switches the power system to energy supply mode.

14. The power system of claim 13, wherein said at least one battery group is formed by a series connection of said batteries.

15. The power system of claim 13, wherein the at least one battery group comprises at least one series of connection of said batteries and at least one set of parallel battery connections.

16. The power system of claim 13, further comprising a pre-programmed control system, said pre-programmed control system comprising either at least one microprocessor or a computer.

17. The power system of claim 13, where said batteries are selected from the group consisting of new rechargeable automobile/vehicle (EV) batteries, used electric automobile/vehicle (EV) batteries, and 12 volt batteries.

18. The power system of claim 13, wherein the switch control system is configured to: a) allow for the connection to the electric grid energy for delivery of power to the energy storage assembly and to said end user starting at a first set time; and b) allow for the disconnection of the grid energy from the energy storage assembly and the end user, and for the connection of energy storage assembly to the end user, at a second set time.

19. The power system of claim 18, wherein said computer or said microprocessor has the ability to select charging times and determine whether renewable sources or the electric grid will be used for power, based upon specific criteria.

20. The power system of claim 19, wherein said computer or said microprocessor allows for a change in programing functions from configuration of the batteries.

21. The power system of claim 13, wherein there is an optimal number of batteries grouped together to optimize retention of energy, within each said at least one rechargeable battery assembly the optimal number of batteries being the maximum number of batteries connected serially while retaining energy over a period of time in the same manner as a single battery.

22. The power system of claim 13, further comprising alternative renewable energy sources connected to the group consisting of the electric power grid, said rechargeable batteries, and combinations thereof.

23. The power system of claim 22, wherein said rechargeable batteries are charged by the current from the group consisting of the electric power grid, said alternative renewable sources of energy, and combinations thereof.

24. The power system of claim 22, wherein said computer or said microprocessor has the ability to select best charging times and determine whether said alternative renewable energy sources or the electric grid is to be used for power, based upon specific criteria.

25. The power system of claim 13, wherein said switch control system has preprogrammed modes selected from the list consisting of: a charging mode; a retention mode; a supplying mode; and combinations thereof.

26. The power system of claim 13, further comprising plurality of sensors, each of said sensors having the ability to sense a state of charge (SoC) and having the ability to switch or connect to different modes of operations or functions.

27. The power system of claim 13, further comprising a flexible configuration allowing for the retaining, recharging, and supplying of energy so that said flexible configurations of said batteries allow for the supply stored energy to said end user while recharging said batteries from renewable sources.

28. The power system in claim 13, wherein said switch control system is pre-programmed with functional modes and comprises a rechargeable battery stored energy level feedback system based upon readings from said SoC sensors.

29. The power system of claim 13, comprising: a) a first said battery group; and b) a second said battery group; wherein a) said first said battery group and said second said battery group are configured to supply electric power to a load and in a first mode of operation the plurality of switches are configured to connect the first said battery group and the second said battery group in series so that the first said battery group and the second battery group can supply electric power to the load and wherein in a second mode of operation, the plurality of switches are configured to connect the first said battery group and the second said battery group in parallel, and disconnect the first said battery group and the second said battery group from the load.

30. The battery assembly of claim 29, further comprising a third said battery group configured to supply electric power to the load, wherein the plurality of switches is configured to: a) in the first mode of operation, connect the first said battery group, the second said battery group, and the third said battery group in series so that each of the said battery groups can supply electric power to the load; and b) in the second mode of operation, connect the first battery group, the second battery group, and the third battery group in parallel, and disconnect the first battery group, the second battery group, and the third battery group from the load.

31. The battery assembly of claim 29, wherein said at least one bi-directional inverter is connected to the first said battery group, the second said battery group, and the electric utility grid.

32. The battery assembly of claim 30, wherein the switch control system is configured to control the plurality of switches to operate in the first mode of operation and the second mode of operation.

33. The battery assembly of claim 32, further comprising a timer in communication with the switch control system, wherein the timer provides timing information to the switch control system.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a pictorial illustration of an integrated power system using the unit/cell concept to integrate electric power storage and supply.

(2) FIG. 2 is a block diagram of an integrated power system using the unit/cell concept to integrate electric power storage and supply.

(3) FIG. 3 is a block diagram of a cell cluster of an integrated power system formed by connecting multiple electric power retention distribution cells at a utility hub.

(4) FIG. 4 is a pictorial illustration of a regional integrated power system formed by multiple cell clusters connected together at a regional utility hub.

(5) FIG. 5 is a block diagram of a regional integrated power system formed by multiple electric power retention distribution cells connected to utility hubs joined together at a regional utility hub.

(6) FIG. 6 is a schematic diagram of an embodiment for the electrical operation of an electric power retention distribution cell.

(7) FIG. 7 shows circuit diagrams of series and parallel battery connections.

(8) FIG. 8 is a circuit diagram of a battery configuration in one embodiment of the battery assembly.

(9) FIG. 9 is a notional chart showing stored energy depletion over time for different battery voltages.

(10) FIG. 10 is an illustration of battery configurations used under test.

(11) FIG. 11 is a graph showing battery voltage versus SoC from 50% to 100%

(12) FIG. 12 is a graph of a manufacturer's data for battery capacity retention (%) over time.

(13) FIG. 13 is a graph of change in battery SoC over 30 days.

(14) FIG. 14 is a graph of change in battery SoC over 180 days.

(15) FIG. 15 is a flowchart showing a method of operation of a cell for delivering power to an end user according to one embodiment.

(16) FIG. 16 is a flowchart showing a method of operating a battery assembly of a cell according to one embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

(17) Embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, parts that are the same or correspond to each other have been given the same reference signs, and redundant descriptions thereof will not be given.

(18) A key element of the system is the use of electric car batteries at the end of their automotive life which can still have about 70 to 80% of their charging capacity when new. Unlike a battery's use in vehicles where conditions are fairly demanding with rapid discharging and charging, a residential/commercial use of the same battery gives the battery a second life once it is finished its automotive application. Use of recycled batteries also favorably adds to the cost/benefit of the system of the disclosure. The stored energy will meet full energy needs for days and when it is not in use, the stored energy can be preserved, nominally for up to a month, while also being available to meet any emergency back-up power situation.

(19) Referring now to FIGS. 1 and 2, FIG. 1 is a pictorial illustration and FIG. 2 is a corresponding block diagram of an integrated power system (IPS) according to the disclosure using the unit/cell concept to integrate electric power storage and supply. The integrated power system 10 includes a cell (or unit) 12 which contain a central control switch (CCS) 14 connected to an outside utility electric grid (UEG) 16, and a battery assembly 18 connected bi-directionally to an inverter/charger unit 20. Herein the central control switch is also simply referred to as control switch and the utility electric grid is at times simply referred to as the grid. Inverter/charger unit 20 is connected also via a bi-directional link to central control switch 14. Inverter/charger unit 20 functions both as a bi-direction inverter and a charger to battery assembly 18, but is referred to herein simply as inverter 20. A power meter 21 is connected in series with switch control 14 to utility electric grid 16. As used herein, units/cells refers to a localized power storage, switching and distribution unit or cell, one example of which is presented in FIGS. 1-2. The preferred term cell is predominately used herein for the localized power storage, switching and distribution system.

(20) The central control switch is also connected to alternate energy or power sources 17 (FIG. 2), such as a wind power generator (WPG) 17a and/or a photovoltaic panel (PVP) 17b (FIG. 1) via one or more directional links to the alternate energy sources. The one or more alternate power sources delivery output power to the battery assembly of the cell. An appropriate interface (not shown) could be used with the battery assembly. As used herein, energy and power, as in energy source or power source are used interchangeably. Central control switch 14 is also connected via one or more directional links to a residential and/or a commercial (residential/commercial) end user 22 of electric energy. Any number of end users could be connected to the cell as indicated by the dashed lines to end user 23 in FIG. 2. Although illustrated as a single additional end user 23, it is understood that end user 23 can represent any number of additional end users connected to cell 12.

(21) FIG. 3 is a block diagram of a cell cluster 24 of an integrated power system formed by connecting multiple electric cells 12a-12d at utility hub 26 which is connected to utility electric grid 16. FIG. 3 shows four distributed and independent units/cells 12 connected together at utility hub 26 to form the cluster; however the number of cells is not so limited. Any number of two or more cells could make up a cluster. There could be, for example, more than four cells, as indicated by the dashed line cell n designated in FIG. 3 as 12n. By utilizing one or more current utility grids, all units/cells are networked-integrated together.

(22) Referring next to FIGS. 4 and 5, FIG. 4 is a pictorial illustration, and FIG. 5 is a corresponding block diagram, of a regional integrated power system formed by multiple cell clusters connected together at a regional utility hub. The embodiment of FIGS. 4-5 is a system arrangement for a regional utility network using clusters of cells connected together through utility hubs, and the utility hubs (A-D in the example of FIG. 5) joined at regional utility hub 28. The number of clusters joined together at a regional utility hub is not limited to four but can consist of two or more clusters. This is indicated in FIG. 5 by utility hub 24n to show that additional cell clusters can be connected to the regional utility hub. Although not illustrated, the same concept can be extended to a country-wide scale. Thus another embodiment of the disclosure is its application in providing a vast regional, or a country-wide, network by interconnecting two or more regional utility hubs together to form an integrated power system made up of individual, localized electric cells (cells).

(23) The described systems and components that center on the cell electric storage and distribution concept work in counter-phase with the utility electric grid's power demand. During the electrical grid's high load demand (usually during the day time), the cell supplies needed electrical power to a home or business by use of the stored DC voltage in combination with an inverter/charger unit that converts the DC power to AC. During the electric grid's low load demand (usually during the night time), stored electrical power in the cell is replenished also by use of the inverter/charger unit which converts AC power from the grid to DC to charge the batteries during night time when the electrical grid's load is usually low and the energy is less costly.

(24) FIG. 6 is a schematic diagram of the electrical operational of a cell. FIG. 6 provides additional schematic details to the block diagram of FIG. 2. Where components in FIG. 6 are the same as in FIG. 2, those components are referenced by the same numbering used in FIG. 2. The cell has a battery assembly (BAA) 18, connected to a bi-directional inverter 20, which connects to central control switch 14. The bi-directional inverter is rated to handle power from 2.5 to 12 kW.

(25) The central control switch includes four circuit breakers, 14a-14d. Circuit breaker 14a protects the circuit for delivery of electric power, when switch 38a is closed, from alternate energy source(s) 17 to the cell and to battery assembly 18. The power from alternate energy source 17 may be received at the cell as either AC or DC power. Hence, the power inputted through circuit breaker 14a is connected to inverter 20 for a determination of whether the received power is AC, and if it is, the AC is inverted to DC for delivery to the battery assembly. If the power received from alternate energy source 17 is DC, then it is delivered as input to the battery assembly without any inversion.

(26) Circuit breaker 14b protects the circuit for delivery of AC electric power, when switch 38b is closed, from the inverter of the cell to the residential or commercial end user 22. Circuit breaker 14c protects the line for delivery of utility electric grid power 16 to the end user 22 when switch 38c is closed. Switch 38c would be closed when the utility electric grid is furnishing the primary electric supply to the end user. Switch 38c might also be closed to allow the grid to provide auxiliary power to the end user (e.g. for some controls) even when the cell is serving as the end user's primary electric supplier. In this case, the end user remains connected to the grid but uses much less grid power, namely only auxiliary power as needed. Circuit breaker 14d protects the circuit for delivery of utility electric grid power, when switch 38d is closed, to inverter 20 of cell 12, where the utility grid AC power is inverted to DC power and provided as a controlled DC power input to the battery assembly. Switch 38e is closed to supply auxiliary power, as needed, from the utility electric grid to alternate energy source 17 for on-site power generation, to inverter 20 which also functions as a battery charger to battery assembly 18, and to the battery assembly. An electric power meter (KV2-GE) 21 is used in the cell to monitor the operation by measuring standard parameters in the industry, such as power, voltage, and current. Meter 36 is connected in series or in parallel, or a combination thereof, with utility electric grid 16 as such connections are known in the industry.

(27) Battery assembly 18 is a battery storage bank with an energy storage capacity of from 9.6 to 50 kWh. Batteries can be connected together by use of series battery connections, parallel battery connections, or a combination of series and parallel battery connections. For example, nine 12 VDC batteries can be connected in series to produce an output of 108 VDC that is inputted to inverter 20 for inversion to AC power. In another arrangement, a set of three 12 VDC batteries can be connected in series to produce an output of 36 VDC, and then three such sets be connected in series to also produce an output of 108 VDC.

(28) In operation, the cell is set to time its connection and disconnection to the end user to supply and not supply, respectively, electrical power to the end user so to reduce or minimize electric power cost to the end user. For example, at a first predetermined time in the evening or night time (the first set time), the control switch 14 connects the cell to the grid (UEG) by closing switch 38d. This causes delivery of grid electric energy to inverter 20 which converts the AC grid power to DC and delivers DC electricity at the inverter's output to charge the batteries in the battery assembly. DC electricity is thus stored in the batteries of the battery assembly during the time that the cell is connected to the grid through switch 38d. At a second predetermined time in the morning (second set time), with the batteries in the battery assembly being fully charged, control switch 14 disconnects the grid by opening switches 38c and 38d and connects (in series) the cell to the end user by closing switch 38b. In this stage, the cell is the main energy supplier to the end user, as DC power stored in battery assembly 18 now flows to inverter 20 where it is converted to AC power and delivered through closed switch 38b to the end user 22. In this situation, switch 38c can optionally also remain closed to provide auxiliary power to the end user if desired.

(29) In case of equipment failure or battery depletion (detected by appropriate monitoring devices, not shown), the control switch connects the grid to the residence or commercial entity and restores regular grid power supply to the end user by closing of switch 38c and opening of switch 38b. During the day and/or night, the cell, and specifically its battery assembly 18, can also be charged by using available alternative energy sources 17, such as solar (photovoltaic cells), wind, or geothermal power generators, by closing switch 38a. These alternative energy sources are referred to as on-site power generation, which encompasses alternate power generation sources in the vicinity of the cell or within a reasonable power transportation distance to the cell. Switch 38e may be closed during either or both of the first and second set times to provide auxiliary power from the grid to the on-site power generation of the alternate energy source, which may consist of one or more alternate energy source, to the inverter 20 and to battery assembly 18.

(30) The control switch and its individual switches may be controlled by a microprocessor, a computer, or by other automated devices. For example, an operator could input into a computer desired first and second set times for designating when the grid or the cell is to be the primary electric supplier to the end user.

(31) It is understood that, although not shown in the figures, standard electrical meters, using either a series or parallel connection as appropriate, circuit breakers, and other devices as used in the delivery and receipt of electrical power could be included in the schematic circuit diagram of FIG. 6 and in connecting the cell to other parts of the described integrated power system.

(32) Battery Configuration

(33) Battery assembly 18 stores the electrical energy of the cell for distribution to one or more end users at preselected times. FIG. 7 shows the basic arrangements for series and parallel connections of multiple batteries. FIG. 7(A) is a circuit for a series connection of nine 12 volt (12 VDC) batteries to give an output voltage of 108 VDC. FIG. 7(B) is a circuit for a parallel connection of three sets of three 12 volt batteries connected in series to give an output voltage of 36 VDC. FIG. 8 is an illustration of one embodiment of a battery arrangement in the battery assembly. The figure shows a battery scheme that utilizes a combination of series and parallel battery configuration, similar to FIG. 7(B), in connecting battery configurations 81a through 81i as indicated by the circuit of FIG. 8. Each battery configuration designated as 81a through 81i consists of three 12 VDC batteries connected in series so that each configuration provides 36 VDC of voltage across its outputs. For simplicity, the three series-connected batteries in each configuration are not individually shown and instead are represented by the respective blocks 81a through 81i. Relay switches (S) 83a-83f are added in the circuit as indicated in FIG. 8 and function to disconnect certain of the batteries 81a-81i as illustrated in order to store and preserve energy for a longer period of time (nominally for up to a month), and to connect the batteries when the stored energy is used as the primary power supply to the end user. In the battery arrangement circuit of FIG. 8, the voltage at the output terminals of the battery assembly 18 (FIG. 6) with relay switches 83a-83f closed is 108 VDC. The voltage level at the output of battery assembly 18 can be achieved by use of different battery connection configurations. The battery scheme of FIG. 8 is shown as one embodiment of a battery arrangement.

(34) Turning next to FIG. 9, a notional chart is presented of stored energy depletion over time for different battery voltages of 36 VDC and 108 VDC. The two energy depletion graphs in FIG. 9 are for demonstration purposes, that is, they are based on predicted figures. Energy leaks that cause energy depletion for a given voltage depend on a number of factors. There are internal leaks, leaks though air (due to humidity, temperature, temperature cycling, etc.), and surface leaks (due to moisture, dust deposits, temperature, etc.). Each of the factors will depend on actual battery types, assembly configuration and voltage. For example electric car battery assemblies usually operate at higher voltages (e.g., 300-440V). At the higher voltages external leaks in real-word conditions can increase significantly during the time. FIG. 9 gives an estimated predicted performance of battery energy storage using assumptions to approximate real world conditions made for various internal and external battery leakage factors. The graphs show greater stored energy depletion over 30 days when the battery level is stored at 108 VDC and a lesser depletion, and hence more favorable results, where the battery level is stored at the lower 36 VDC.

(35) Electrical use for U.S. households is 110 VAC. The use of an inverter to convert DC voltage to AC voltage, and the use of transformers to increase or decrease voltage to match residential/commercial use create additional energy losses. Having a minimal difference in the level of the inputted DC voltage to an inverter from the desired output AC voltage is beneficial in that it minimizes energy loss in the inversion process, and thus matching the input/output voltages is most desirable. Optimal results are therefore realized with a 108 VDC output from battery assembly 18.

(36) However, to store energy in batteries for a long time (e.g., 30 days) and decrease energy losses during this time due to leaks (e.g., surface/air discharge and self/internal discharge), a lower voltage (than 110 VDC) will help greatly to preserve the energy, as FIG. 9 shows. Thus, to decrease losses during storage, storing the batteries at the more favorable 36 VDC level, as is accomplished by the circuit of FIG. 8, will extend energy storage over time when the cell is not in use. The design in one embodiment utilizes the combination of series and parallel battery configurations as shown in FIG. 8 where the S-relay switches selectively disconnect batteries in order to store and preserve energy for the longer time of up to a month.

(37) Test Description:

(38) Two sets of batteries, each consisting of nine 12v batteries, were assembled as shown in FIG. 10. In the first set (FIG. 10(A)), only 3 batteries were connected in series to form a group, and the three groups were disconnected from one another. This formed three 36 VDC units. In the second set (FIG. 10(B)), all batteries were connected in series to form a single 108 VDC unit. All batteries were charged to identical levels and then disconnected from the charger and kept in the same environment and conditions for 30 days. During that time measurements were taken of the stored energy in each set at the end of every 10-day period by measuring voltage and current. At the end of the 30-day period the 3 group 36 V batteries of the first set were connected in series to achieve 108 VDC output unit, similar to that of the second set. Then, the total residual stored energy was measured in both sets. This allowed a comparison to be made of the performance for energy storage of the two sets of nine 12 V batteries. These are the measurement results plotted in the chart of FIG. 9, discussed previously. The test confirms that it is important to disconnect units so to store the energy in the batteries at the lower (36V) DC voltage to achieve greater energy storage (less loss) for a longer period of time (30 days)

(39) Battery Assembly State of Charge Test Results.

(40) Determining the State of Charge (SoC) of a battery is a key factor for battery quality control in all applications. SoC as an indicator of stored energy is measured using methods accepted by the industry. See, for example, Methods for State-of-Charge Determination and their Applications, Sabine Piller et al., Journal of Power Sources, 2001, pp. 113-120, herein incorporated by reference. Long term energy storage testing typically uses type PS-1250 batteries. An exemplary SoC graph is presented in FIG. 11 which plots battery voltage as a function of its SoC in showing the relationship between a battery's open circuit voltage and its SoC. Use of this graph helps to accurately determine changes in battery electrical charge levels over time by measuring open circuit voltage. In view of this and other battery quality control advances, battery operation is currently changing to what could more accurately be called battery management than simply battery protection.

(41) To determine the best battery configuration for the battery assembly 18 of cell 12, tests were conducted to determine the battery's retention of its electric charge using different configurations. SoC was measured for purposes of this disclosure using methods accepted by the industry.

(42) A standard 12 volt, lead acid battery was used. Specifically the inventor used a Power Sonic battery model PS-1250F1 manufactured by Power-Sonic Corporation in San Diego, Calif., rated at 12 volt and 5.0 amp-hr. This specific type of battery was used for demonstration and proof of concept purposes. While the actual results (numbers of SoC) for metal ion batteries may vary, the concept for an optimal set of batteries as described will still apply.

(43) Two battery configurations were tested. In one configuration, nine 12 volt batteries were connected in series to give an output of 108 VDC, as illustrated in FIG. 10(B). In the other configuration, nine 12 volt batteries were connected in series in groups of three, and the three groups then connected in parallel, to give an output of 36 VDC of each group, as illustrated in FIG. 10(A). Both configurations (A) and (B) were left open circuited for purposes of the test. Each time each battery of FIGS. 10(A) and 10(B) was disconnected from any load for its SoC measurement 100, that it, an open circuit measurement 100 was made. The test environment was controlled and maintained. The temperature was at 63 F, and humidity at 28-30%. The resulting plot of data is as shown on the graph of FIG. 11, which plots the open circuit voltage of the battery versus its SoC, where the data points are the average of the measurements made on each of the nine batteries. FIG. 11 shows that at the start point where the battery is 93% charged its starting voltage is approximately 12.85 VDC. As the battery charge decreases over time, its open circuit voltage decreases rather linearly down to approximately 12.05 volts at a 50% charge level (with appropriate extrapolation done on the graph).

(44) The tests were conducted using three sets of battery assembly: set #1 consisted of nine 12 VDC batteries connected in series (FIG. 10 (B)) to give a nominal 108 VDC at the output terminals; set #2 consisted of three 12 VDC batteries connected in series in three groups, and the three groups were connected in parallel (FIG. 10 (A)) to give a nominal 36 VDC at the output terminals; set #3 was a control set consisting of one 12 volt battery.

(45) FIG. 12 presents the manufacturer's data of its battery's capacity retention during the storage time standing period of from 0 to 20 months for different temperatures from 41 F-104 F.

(46) Test Results

(47) In real-world conditions and environment, energy stored in a battery can change/deplete due to internal leaks and external conditions (humidity, moisture dust, temperature, etc.). Internal battery leakage is recognized in the industry at about 5%. The external leakage can be studied ideally with control of outside factors, such as temperature, humidity, etc. External factors were controlled in the actual tests conducted the results of which are presented in FIGS. 13-14 and these confirm the prediction results of FIG. 9. One set of actual test results are shown in the graph of FIG. 13, which plots data, again from the average taken of measurements at the output terminals of the three sets under test, SoC over a standing time of from 0 to 30 days. The test results show that there were appreciable differences in state of charge between battery assembly sets 1 (912V) and 2 (312V). However, there was no difference observed between set 2 (312V) and control set 3 (112V). The conclusion is that set 2 (36V) is optimal for longer term energy storage. The experiment proves that even in a well-controlled environment (best case scenario), stored energy will deplete differently based on the battery set configuration.

(48) The same test was extended to a longer standing time (storage time) of 6 months, and the graph of FIG. 14 shows these results. This longer term test shows that sets #2 (312V) and #3 (112V) after 180 days, have very similar states of charge, yet the SoC for set #1 (912V batteries) is much less. This is consistent with the results of the shorter 30-day storage time test. Both tests thus establish that by switching to 36V battery sets, these 36V sets will preserve stored energy on the same level as a single battery unit. The important lesson from the test is that, when in longer term storage, dividing the battery assembly into smaller open circuit voltages ( of the total voltage to be used) will decrease the internal leak of energy from the batteries.

(49) FIG. 15 shows a flow chart for a method of operating a cell for delivering power to an end user such as shown in the embodiment of FIGS. 2 and 6. In step S 1501, a cell is formed with a central control switch having a plurality of switches, a bi-directional inverter and a batter assembly operationally connected together such as, for example, shown in FIG. 6. In step 1503, the cell is electrically connected to an electric utility grid, to an alternate power supply and to an end user. The alternate power supply could be one or more alternate power supplies, such as generated by wind power, hydro-electric power or photovoltaic cells. The alternate power supply could be one or more of these combinations of alternate power supplies. The end use could be one or more end users of electricity.

(50) In step S 1505, a selection is made as to whether or not to deliver power form the primary supply, which in this embodiment is from the electric utility grid, to the end user. If the primary supply or supplier is selected, the method proceeds to step S 1507 which connects to the end user. If the primary supply is not selected, the method proceeds to step S 1508 where another selection is made at step S 1511. Here the selection is whether to store the batteries, and specifically to store the charge of the batteries that make up the battery assembly, or to charge the batteries in the battery assembly, or to connect the battery assembly as the primary power supply to the end user. If the selection is to store the charge of the batteries in the battery assembly, an appropriate connection is made by the cell's central control switch to connect or disconnect selected groups of batteries in the battery assembly to the battery assembly's storage state, as indicated at step S 1515. It is understood that the central control switch can be connected to a computer or microprocessor for switch activation, and also that timers could be used to automate further the timing and manner in which the central switch control is to be operated.

(51) If the selection is made to charge the batteries, then an appropriate switch control is activated to connect a power charging supply to the battery assembly to charge the batteries in the battery assembly as indicated at step S 1509. The power charging supply could include the electric utility grid power and/or power from other alternate power sources, such as wind and photovoltaic power sources as mentioned above. The alternate power sources or the electric utility grid power source can be used individually, in combination, or selectively along or in combination used any power charging supply. If the selection is to use the battery assembly as the primary power supply to the end user, the appropriate switching connections are made to connect the battery assembly to the end user as indicated at step S 1513. The cell's bi-directional inverter is used when charging the battery assembly from the power charging supply by inverting AC power to DC power for delivery to the battery assembly. The cell's bi-directional inverter is also used when the battery assembly is selected as the primary power supply to the end user by inverting the DC battery assembly power to AC power for delivery to the end user.

(52) FIG. 16 shows a flowchart for a method of operating a battery assembly such as used in an embodiment of the cell. In step S 1601, a battery assembly is formed by connecting batteries together. The connection could be a series connection or a parallel connection of batteries. It could also be a combination of series and parallel connections of groups of batteries. In step S 1603, one or more switches are installed at predetermined locations in the battery assembly so to connect and disconnect batteries or groups of batteries. For example, multiple series connections of batteries could form battery groups, and a switch or switches can be used to connect or disconnect the groups of batteries. In one embodiment, groups of batteries are disconnected by activation of the one or more switches when the battery assembly is in storage and not being used for delivery of power to the end user, and are connected by activation of the one or more switches when the battery assembly is being used for changing of the batteries from an outside power charging supply source, or for delivery of electric power to the end user.

(53) In step S 1605, a selection is made as to whether or not the battery assembly is to be used to supply electric power as the primary supplier to the end user. If the battery assembly is selected to be the primary supplier, the battery assembly is appropriately switched so that the output of the battery assembly is connected to the end user, as indicated at step S 1607. The DC voltage of the battery assembly may be connected to an inverter to invert the DC voltage to AC voltage for delivery to the end user. Since the inverter is a component separate from the battery assembly, it is not shown in FIG. 16, but the line of S 1607 would connect to the inverter in routing the electric power of the battery assembly to the end user. It is understood that there could be more than one end user.

(54) If the battery assembly is not selected to be the primary supplier, the battery assembly is appropriately switched so that the process proceeds, as indicated by step S 1608, to the next step S 1611 where a selection is made as to whether the battery assembly is to be charged or stored. If the battery assembly is to be charged, the battery assembly is appropriately switched to connect to an outside power charging supply as indicated at step S 1609. The outside power charging supply could be from alternate energy sources, such as photovoltaic cells, wind turbines or hydro-electric generators. The power charging supply could also be from the electric utility grid. Any one of these exemplary energy sources or any combination of alternate energy sources can be used as the power charging supply of FIG. 16 to charge the battery assembly. In one embodiment, the switching in of a power charging supply can be automated, for example by connecting a voltage level detector to the battery assembly, and when the voltage level at output terminals of the battery assembly drop below a preset level, then the battery assembly is automatically switched to connect to the power charging supply. In another embodiment, power from an alternate energy source, such as photovoltaic cells or wind turbines which generate electricity only in certain conditions (the presence of sunlight or wind, in the two examples given), could be connected to an energy storage device as part of the battery assembly. Such an energy storage device could be, for example, a capacitor or bank of capacitors, and the battery assembly then selectively connected to that energy storage device when the battery assembly is to be charged.

(55) If the selection is made to store the charge of the batteries in the battery assembly, then the battery assembly is appropriately switched so that the outside power charging supply is not connected and the batteries are stored as indicated at step S 1613 in an open circuit state. In one embodiment, when switched to the storage state, one or more switches in the battery assembly are activated to groups of batteries connected together where each group has an output terminal voltage that is less than the output voltage of the battery assembly when all the batteries are connected together.

(56) Note that the processes or method steps included in FIGS. 15 and 16 and the descriptive text associated therewith do not have to be performed chronologically in the order described in the flowcharts. Some of the processes may be performed in a parallel manner or may be performed as a sub-routine.

(57) The disclosure explains how residential or commercial distributed generation and storage can be networked through utilities. This will ease the stress on electrical grid during peak times. Furthermore, if regulated and controlled correctly, use of the cell concept will provide much needed power storage ballast for the electric utility grid so to reduce or possibly eliminate crashes/blackouts. After scaling to a significant number of systems participating in the network (achieving a critical mass), the integrated and distributed character of this disclosure can at the same time add robustness and redundancy which can withstand large scale/regional emergencies. Hence, the residential/commercial power generation and storage capability is a critical enabler to achieve a robust and sustainable energy system. FIGS. 4-5, as previously discussed, presents an example of how distributed and independent cell sites can be used together to form a cell cluster through a utility hub, which can then connect to other clusters through a regional utility hub to create a regional or country-wide network. This concept allows localizing power emergencies/outages and eliminating a network-wide cascade/domino effect by restricting any such adverse event to a predefined regional level.

(58) The embodiments disclosed in this application are to be considered in all respects as illustrative and not limiting. The scope of the disclosure is indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.