GB2628025A - Energy storage device and methods of charging - Google Patents

Energy storage device and methods of charging Download PDF

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Publication number
GB2628025A
GB2628025A GB2318529.1A GB202318529A GB2628025A GB 2628025 A GB2628025 A GB 2628025A GB 202318529 A GB202318529 A GB 202318529A GB 2628025 A GB2628025 A GB 2628025A
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GB
United Kingdom
Prior art keywords
current path
power source
sodium
ion cells
battery management
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
GB2318529.1A
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GB202318529D0 (en
Inventor
Roche Noel
Louis Fantham Thomas
Azhar Iqbal Muhammad
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Faradion Ltd
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Faradion Ltd
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Publication date
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Priority to GB2318529.1A priority Critical patent/GB2628025A/en
Publication of GB202318529D0 publication Critical patent/GB202318529D0/en
Publication of GB2628025A publication Critical patent/GB2628025A/en
Pending legal-status Critical Current

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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/42Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44Methods for charging or discharging
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/054Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/42Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44Methods for charging or discharging
    • H01M10/441Methods for charging or discharging for several batteries or cells simultaneously or sequentially
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/42Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44Methods for charging or discharging
    • H01M10/446Initial charging measures
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H02J7/0014Circuits for equalisation of charge between batteries
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H02J7/0014Circuits for equalisation of charge between batteries
    • H02J7/0016Circuits for equalisation of charge between batteries using shunting, discharge or bypass circuits
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007Regulation of charging or discharging current or voltage
    • H02J7/00712Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/007182Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H02J7/345Parallel operation in networks using both storage and other dc sources, e.g. providing buffering using capacitors as storage or buffering devices

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Secondary Cells (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

An energy storage device 10 includes a charging circuit 24 which is connected to all of one or more sodium-ion cells 20 and all of one or more battery management systems 22. The charging circuit provides a first current path 32 which transmits power from a power source 28 to all of the sodium ion cells, bypassing the battery management systems, to increase the potential of the cells from a first potential to a second potential which can operate the battery management systems. In response to operation of the battery management systems current is provided from a power source 42, via a second current path 36 of the charging circuit which includes the battery management systems, to increase the potential of the sodium ion cells to a third cell potential. A further energy storage device includes the charging circuit with first and second current paths connected to all of one or more supercapacitors and all of one or more battery management systems. The energy storage device may be useful for charging sodium-ion batteries which have been transported at low voltage, for example 0 V, and are below the lower voltage limit of operation of the battery management system.

Description

ENERGY STORAGE DEVICE AND METHODS OF CHARGING
FIELD OF THE INVENTION
The present invention relates to a novel energy storage device, particularly an energy storage device that includes one or more sodium-ion cells. The invention also relates to a method of charging said energy storage device.
BACKGROUND OF THE INVENTION
Sodium-ion cells are analogous in many ways to the lithium-ion cells that are in common use today; they are both reusable secondary cells that comprise an anode (negative electrode), a cathode (positive electrode) and an electrolyte material, both are capable of storing energy, and they both charge and discharge via a similar reaction mechanism. When a sodium-ion (or lithium-ion) cell is charging, Na' (or Li') ions de-intercalate from the cathode and insert into the anode. Meanwhile charge balancing electrons pass from the cathode through the external circuit containing the charger and into the anode of the battery. During discharge the same process occurs but in the opposite direction.
Sodium-ion cells have generated considerable interest and are considered as one of the most promising candidates for next-generation battery technology. However, one area that needs more attention is the development of novel energy storage devices that includes one or more sodium-ion cells.
A fundamental problem with lithium-ion cells is that their transportation and/or storage is inherently hazardous because, in most cases, lithium-ion cells are not safe when i) stored in a fully discharged state; or fi) discharged down to 0 volts or close to 0 volts. This is because copper from the current collector for the anode (negative) electrode dissolves as copper ions into the electrolyte, and on subsequent recharge, the dissolved copper ions will then plate on internal surfaces of the cell to form electrically conductive pathways. This not only reduces the capacity of the cell, but also results in the formation of internal short circuits and subsequent thermal runaway of a lithium-ion cell.
Discharging a lithium-ion cell to OV or close to OV (even if the cell is not charged again) can have serious consequences as the internal microstructure of the cell is already compromised by that point. For instance, issues such as: internal shorting due to growth of metallic dendritic copper, a decrease in the mechanical integrity of the separator, a weakened anode adhesion to the copper current collector (due to the dissolution of the copper current collector during overdischarge), reduced porosities in the cathode, and blockage of electrochemical active sites on the cathode can not only result in rapid capacity loss, but also pose serious thermal hazards such as dangerous temperature spikes which can result in thermal runaway.
Understandably this is of major concern, particularly to airlines, and to reduce these safety concerns, in 2013 the International Civil Aviation Organisation introduced very stringent controls on the bulk air transportation of lithium-based cells and implemented rules to control both the size (watt hours rating and amount of lithium) of lithium-ion batteries that are permitted to be transported, as well as the number of batteries allowed in each consignment.
Therefore, the best-known way to handle lithium-ion battery cells is to avoid any storage condition at or close to 0 Volts by ensuring that immediately upon manufacture, the lithium-ion battery is conditioned by a process involving at least two or three charge/discharge cycles, followed by a final charge to at least around 30 to 40% stage-of-charge. The cell must then be degassed and finally resealed before it is ready for storage and/or transportation.
Unlike lithium-ion cells, sodium-ion cells and supercapacitors can be safely stored and/or transported at or close to 0 Volts. For sodium ion cells this is the subject of International PCT Application published as WO 2016/027082 Al. In particular, disclosed is a process for making sodium-ion cells which are capable of safe storage and/or transportation. This is performed by discharging a charged/discharged sodium-ion cell in the range -0.1 to 1 Volts to thereby produce a sodium-ion cell that is in a state of charge (SOC) of from 0% to 20%.
Whilst WO 2016/027082 Al discloses that it is safe to maintain a sodium-ion cell in the range -0.1 to 1 Volts for safe storage and/or transportation, a new problem has now arisen. In particular, when an energy storage device that includes one or more systems for managing and or controlling cells such as a battery management system as well as one or more sodium-ion cells that have been subject to the process of WO 2016/027082 Al it is not clear how such an energy storage device is able to be charged. This may occur for instance when such an energy device has been transported to an end user at OV, and thus the energy storage device requires charging (e.g., during commissioning) before use.
A battery management system of an energy storage device will typically act to isolate one or more metal-ion cells included in said device from an associated load (i.e., an item which would discharge the device), or an associated power source (i.e., an item which would charge the device) when the average voltage across each cell falls below -1.2V which may be when the device is being stored and/or transported, and/or during a maintenance operation. This isolation may be directly performed by the battery management system, which may control a switching/isolating device such as a contactor or a Metal Oxide Semiconductor Field-effect Transistor (MOS-FET) to isolate one or more cells.
Commercially available battery management systems available at the priority date of this application are designed for use with lithium-ion cells. Therefore, during safe storage and/or transportation and/or maintenance of an energy storage device that comprises one or more lithium-ion cells, energy will always be available to power the battery management system. This is because discharging a lithium-ion cell to a fully discharged state; or ii) down to 0 volts or close to 0 volts can have serious consequences as set out above.
Therefore, when such an energy storage device that comprises one or more lithium-ion cells has been transported to an end user, and thus requires charging, the battery management system can be operated to enable charging to occur. That is, the battery management can act to remove any isolation between one or more lithium-ion cells and an associated power source because energy remains in the energy storage device. Expressed another way, an energy storage device that comprises one or more lithium-ion cells should never reach a lower voltage limit that cannot operate the battery management system to remove any isolation between one or more lithium-ion cells and an associated power source, to enable charging to occur.
In contrast, an energy storage device that comprises one or more sodium-ion cells could reach a lower voltage limit that cannot operate the battery management system. This is particularly so if all of the one or more sodium-ion cells in an energy storage device have been subject to the process of WO 2016/027082 A1. Consequently, because the battery management system cannot be operated (e.g., because all of the one or more sodium-ion cells are at OV), it is not possible to remove the isolation between all of the one or more sodium-ion cells and an associated power source to enable charging of the energy storage device through the battery management system.
Another limitation is the lower voltage limit of typical battery charging systems. If the energy storage device is at a voltage below the lower voltage limit of the charging system, energy cannot be delivered to charge the battery and an additional power source and/or manual intervention is required in such situations. Yet another limitation arises because commercial off the shelf battery management systems also need the voltage levels of both the charger and the battery to be in close proximity. Due to low impedances between storage devices and charging systems, there is a risk of high current flows in cases of significant voltage differences, which can cause damage to a battery management system.
The invention therefore aims to mitigate or eliminate one or more of the aforesaid disadvantages of the known art.
In particular, the aim of the present invention is therefore to provide a novel energy storage device which can be charged from cell potentials in which a battery management system cannot be operated (e.g., OV). The approach of the present invention will therefore reduce and/or eliminate the difficulties of charging an energy storage device comprising one or more battery systems and one or more sodium-ion cells, in which all of the one or more sodium-ion cells may have a cell potential of 0 volts or close to 0 volts, and in which all of the one or more battery management systems cannot be operated to remove the isolation between all of the one or more sodium-ion cells and an associated power source to enable charging to occur.
The methods and/or uses of the present invention will also enable efficient charging of an energy storage device.
The present invention achieves these aims by providing a novel energy storage device for use with a power source, the energy storage device comprising: one or more sodium-ion cells; one or more battery management systems connected to all of the one or more sodium-ion cells; and a charging circuit connected to all of the one or more sodium-ion cells and all of the one or more battery management systems, the charging circuit being configured to: (a) directly or indirectly provide a first current path having a first conductor to transmit power from the power source to all of the one or more sodium-ion cells to, in use, increase a first cell potential of all of the one or more sodium-ion cells to a second cell potential that can operate all of the one or more battery management systems; (b) directly or indirectly provide a second current path having a second conductor to transmit power from the power source to all of the one or more sodium-ion cells, in which the second current path includes all of the one or more battery management systems; and (c) in response to the operation of all of the one or more battery management systems, in use, provide current flow from the power source via the second current path to all of the one or more sodium-ion cells to increase the second cell potential of all of the one or more sodium-ion cells to a third cell potential; and in which the first current path bypasses all of the one or more battery management systems in the second current path to pass a current from the power source via the first current path to all of the one or more sodium-ion cells.
Advantageously, because the first current path bypasses all of the one or more battery management systems in the second current path, the cell potential of all of the one or more sodium-ion cells can be increased from a first cell potential that is not able to operate all of the one or more battery management systems (e.g., OV) to a second cell potential that can operate all of the one or more battery management systems (e.g., 1.2V or greater). Consequently, the battery management system can then be operated to enable further charging of the energy storage device via the second current path, for instance by using an external DC power source, which is preferably a photovoltaic power source.
As used herein the term "battery management system" means a system that includes means to isolate all of the one or more sodium-ion cells included in an energy storage device from an associated load (i.e., an item which would discharge the device), or an associated power source (i.e., an item which would charge the device) when the average cell potential of all of the one or more sodium-ion cells falls below a certain average cell potential (i.e. falls below the second cell potential). Such an average cell potential may occur when the energy storage device is being stored and/or transported, and/or during a maintenance operation.
The term "cell potential" as used herein means an average cell potential which is measured across all of the one or more sodium-ion cells that are connected together in a series circuit. That is, the total potential measured across the cells connected in series divided by the number of cells in series. That is, for instance, in contrast to a parallel circuit. This definition therefore applies particularly to the terms "first cell potential", "second cell potential" and "third cell potential" as used herein.
In one embodiment, the second cell potential is a cell potential of 1.0V or greater, optionally 1.2V or greater. Preferably, the second cell potential is a cell potential from about 1V to about 3V.
More preferably, the second cell potential is a cell potential from about 1.2V to about 3V.
Preferably, all of the one or more battery management systems include one or more switches which are operable to move from an open position to a closed position when a first cell potential of all of the one or more sodium-ion cells has increased to a second cell potential.
In one embodiment, the third cell potential is a cell potential of 1.5V or greater. Preferably, the third cell potential is a cell potential from about 1.5V to about 4.5V.
More preferably, the third cell potential is a cell potential from about 2V to about 4.2V Preferably, the first current path and/or second current path comprises a positive conductor and a negative conductor. It will be appreciated that one of the positive or negative conductors maybe shared by both the first and second current path.
In one embodiment, the first current path and the second current path are configured to both use the same power source. Advantageously, this avoids the need for two or more power sources.
In one embodiment, the first current path is connected with the second current path to form a bypass line, ideally using one or more electrical connections. Preferably, one end of the bypass line is connected with the second current path on one side of all of the one or more battery management systems and preferably the other end of the bypass line is connected with the second current path on the other side of all of the one or more battery management systems.
Preferably, the bypass line includes one or more diodes and/or one or more voltage convertors. Ideally, at least one of the one or more voltage convertors includes a DC / DC converter.
Preferably, the bypass line includes one or more current overload devices. Such current overload devices may include a fuse, and ideally a resettable fuse.
Preferably, the bypass line includes a device selected from the group consisting of a diode, a voltage convertor, a current overload device, or a combination thereof.
Preferably, the bypass line further includes one or more switches. Ideally, when the switch is activated (i.e., it is switched 'ON'), current flows, in use, from the power source via the bypass line to all of the one or more sodium-ion cells.
Preferably, the energy storage device further comprises one or more input terminals connected to the second current path, which are typically connectable to an output of the power source. Ideally, the charging circuit is therefore so configured that in use current flows from the one or more input terminals via the second current path to all of the one or more sodium-ion cells.
Preferably, the energy storage device further includes a power source. The power source is ideally a DC power source. Preferably, the power source is a photovoltaic power source.
In one embodiment, the energy storage device of the present invention is for use with a first and a second power source, and in which the charging circuit is further configured to: (a) directly or indirectly provide a first current path having a first conductor to transmit power from the first power source to all of the one or more sodium-ion cells to, in use, increase a first cell potential of all of the one or more sodium-ion cells to a second cell potential that can operate all of the one or more battery management systems; (b) directly or indirectly provide a second current path having a second conductor to transmit power from the second power source to all of the one or more sodium-ion cells, in which the second current path includes all of the one or more battery management systems; and (c) in response to the operation of all of the one or more battery management systems, in use, provide current flow from the second power source via the second current path to all of the one or more sodium-ion cells to increase the second cell potential of all of the one or more sodium-ion cells to a third cell potential; and in which the first current path bypasses all of the one or more battery management systems in the second current path to pass a current from the first power source via the first current path to all of the one or more sodium-ion cells.
Again, because the first current path bypasses all of the one or more battery management systems in the second current path, the cell potential of all of the one or more sodium-ion cells can be increased from a first cell potential that is not able to operate all of the one or more battery management systems (e.g., OV) to a second cell potential that can operate all of the one or more battery management systems (e.g., 1.2V or greater). Consequently, the battery management system can then be operated to enable further charging of the energy storage device via the second current path, for instance by using an external DC power source, which is preferably a photovoltaic power source.
Preferably, the energy storage device comprises a switch in the first current path which is connectable with the first power source. Ideally, the charging circuit is configured so that when the first switch is activated (i.e., it is switched from OFF' to ON'), current flows, in use, from the first power source via the first current path to all of the one or more sodium-ion cells. The use of a switch which is connectable with the first power source advantageously allows the first power source to be selectively switched ON and OFF as appropriate at the discretion of a user. For instance, it may be desirable to keep all of the one or more sodium-ion cells at 0 volts or close to 0 volts during storage and/or transportation, and/or during a maintenance operation, but then increase the cell potential after such an event has occurred at the discretion of a user.
Preferably, the energy storage device further comprises one or more input terminals connected to the first current path. Ideally, these are connectable to an output of the first power source. Preferably, the charging circuit is configured that in use current flows from the one or more input terminals via the first current path to all of the one or more sodium-ion cells.
The use of one or more input terminals, ideally two or more input terminals, enables better user interaction with the energy storage device and allows an output of a power source to be easily connectable with the energy storage device. Preferably, the one or more input terminals comprises an IEC connector. Alternatively, the one or more input terminals may comprise two single pole connectors, one positive connector, and one negative connector. A specific example may include Amphenol RADSOK®.
Preferably, the first current path comprises one or more current limiting elements such as a diode, a MOSFET or a DC/DC converter transistor ideally operating in the linear region.
Preferably, the one or more input terminals are connected to the first current path via one or more current limiting elements such as a diode, a MOSFET or a transistor ideally operating in the linear region. Highly preferably, the current limiting element is a diode.
Preferably, the energy storage device comprises an output device that provides an indication that all of the one or more sodium-ion cells are at a cell potential of less than 1.2V, ideally less than 1.0V, and most ideally at a cell potential of OV or close to OV (e.g. ± 0.5V). An indication in this context is dependent upon how the device is powered as discussed below.
The use of an output device is advantageous because it ensures that all of the one or more sodium-ion cells are easily verifiable at a certain cell potential (e.g., DV or close to OV) which may be important during storage and/or transportation, and/or during a maintenance operation. More particularly, UN shipping regulations of sodium-ion cells suggest that under certain conditions it will be a requirement that such cells do not contain any electrical energy, and this should be easily verifiable. Therefore, it is desirable that the output device maybe a visual output device, such as a bulb or a light-emitting diode (LED). Ideally, when powered from the first power source the visual output device would be illuminated. Alternatively, when powered from all of the one or more sodium-ion cells, the visual output device would not be illuminated.
In one embodiment the output device is connectable with the power source, such as the first power source. Alternatively, the output device is connectable with all of the one or more sodium-ion cells.
Preferably, the energy storage device comprises a first power source. This is typically connected to all of the one or more sodium-ion cells, preferably via one or more current limiting elements such as a diode, a resistor, a MOSFET or a transistor ideally operating in the linear region. The use of one or more current limiting elements allows for current limitation from the first power source to all of the one or more sodium-ion cells.
Preferably, the first power source comprises one or more batteries, ideally non-rechargeable batteries. These may be lead-acid, silver-zinc, lithium iron disulphide or alkaline batteries such as those known in the prior art. An AA (LR6) battery pack is one example. Ideally, the first power source is a portable power source.
By providing the energy storage device with a first power source that comprises one or more batteries this advantageously permits an increase of a first cell potential of all of the one or more sodium-ion cells connected in series to a second cell potential that can operate all of the one or more battery management systems.
Preferably, the energy storage device comprising a housing, and ideally the first power source is enclosed within the housing of the energy storage device. That is, the first power source is preferably contained within the same housing as the energy storage device of the present invention. As such, this provides a more user-friendly charging experience and saves time connecting the energy storage device to an accompanying separate power source.
Preferably, the first power source comprises one or more primary electrochemical cells. Primary electrochemical cells in this context means electrochemical cells which are non-rechargeable.
In one embodiment, all of the one or more sodium-ion cells are at a first cell potential of less than 1.2V, ideally less than 1.0V, more ideally less than 0.5V. That is, in one embodiment the first cell potential is a cell potential of less than 1.2V, ideally less than 1.0V, and more ideally less than 0.5V.
In one embodiment, all of the one or more sodium-ion cells are at a first cell potential from about -2.5V to about -0.5V. That is, in one embodiment the first cell potential is a cell potential from about -2.5V to about -0.5V.
In one embodiment, all of the one or more sodium-ion cells are at a first cell potential from about OV to about -0.5V. That is, in one embodiment the first cell potential is a cell potential from about OV to about -0.5V.
In one embodiment, all of the one or more sodium-ion cells are at a first cell potential of about OV to about 0.5V, and ideally about OV. That is, in embodiment the first cell potential is a cell potential from about OV to about 0.5V, and ideally about OV.
Preferably, the energy storage device is combined or integral with a portable power source.
Preferably, all of the one or more battery management systems in the second current path will not facilitate the second current path at a cell potential of less than the lower operating voltage of a commercially available low power microcontroller. The lower limit of a typical commercially available low power microcontroller is 1.8V, in some cases 1.2V, or in further cases 1.0V. That is, all of the one or more battery management systems will not permit current flow from the second power source to all of the one or more sodium-ion cells at a cell potential of less than 1.2V (e.g., OV), or optionally less than 1.0V.
Thus, preferably, all of the one or more battery management systems in the second current path will not facilitate the second current path at a cell potential of less than 1.2V, or optionally less than 1.0V.
Indeed, in a contemporary typical Commercial Off The Shelf (COTS) battery management system, a voltage of -1.0V or greater is required to operate the battery management system because of the intrinsic requirements of microcontrollers and MOSFETS. Thus, when all of the one or more sodium-ion cells have a cell potential of less than 1.2V (optionally less than 1.0V), the battery management system is not able to operate.
Preferably, the energy storage device comprises a second power source.
Preferably, the second power source is a DC power source, ideally a photovoltaic power source.
The energy storage device of the present invention is preferably a sodium-ion battery pack or a sodium-ion battery module.
The present invention also provides, in another aspect, a photovoltaic power source associated or integrated with an energy storage device as disclosed herein.
The present invention also provides, in another aspect, a DC power source associated or integrated with an energy storage device as disclosed herein.
The present invention also provides, in another aspect, a method of charging an energy storage device, the method comprising: a) providing an energy storage device comprising one or more sodium-ion cells, one or more battery management systems connected to all of the one or more sodium-ion cells, and a charging circuit connected to all of the one or more sodium-ion cells and all of the one or more battery management systems; b) associating or integrating the energy storage device with a power source; c) directly or indirectly providing a first current path having a first conductor to transmit power from the power source to all of the one or more sodium-ion cells to, in use, increase a first cell potential of all of the one or more sodium-ion cells to a second cell potential that can operate all of the one or more battery management systems; d) directly or indirectly providing a second current path having a second conductor to transmit power from the power source to all of the one or more sodium-ion cells, in which the second current path includes all of the one or more battery management systems; and e) in response to the operation of all of the one or more battery management systems, in use, providing current flow from the power source via the second current path to all of the one or more sodium-ion cells to increase the second cell potential of all of the one or more sodium-ion cells to a third cell potential; and in which the first current path bypasses all of the one or more battery management systems in the second current path to pass a current from the power source via the first current path to all of the one or more sodium-ion cells.
In one embodiment, the second cell potential is a cell potential of 1.0V or greater, optionally 1.2V or greater. Preferably, the second cell potential is a cell potential from about 1V to about 3V.
More preferably, the second cell potential is a cell potential from about 1.2V to about 3V.
Preferably, all of the one or more battery management systems include one or more switches which are operable to move from an open position to a closed position when a first cell potential of all of the one or more sodium-ion cells has increased to a second cell potential.
In one embodiment, the third cell potential is a cell potential of 1.5V or greater. Preferably, the third cell potential is a cell potential from about 1.5V to about 4.5V.
More preferably, the third cell potential is a cell potential from about 2V to about 4.2V Preferably, the first current path and/or second current path comprises a positive conductor and a negative conductor. It will be appreciated that one of the positive conductor or negative conductor maybe shared by both the first and second current path.
In one embodiment, the first current path and the second current path are configured to both use the same power source. Advantageously, this avoids the need for two or more power sources.
In one embodiment, the first current path is connected with the second current path to form a bypass line, ideally using one or more electrical connections. Preferably, one end of the bypass line is connected with the second current path on one side of all of the one or more battery management systems and preferably the other end of the bypass line is connected with the second current path on the other side of all of the one or more battery management systems.
Preferably, the bypass line includes one or more diodes and/or one or more voltage convertors. Ideally, at least one of the one or more voltage convertors includes a DC / DC converter.
Preferably, the bypass line includes one or more current overload devices. Such current overload devices may include a fuse, and ideally a resettable fuse.
Preferably, the bypass line includes a device selected from the group consisting of a diode, a voltage convertor, a current overload device, or a combination thereof.
Preferably, the bypass line further includes one or more switches. Ideally, when the switch is activated (i.e., it is switched 'ON'), current flows, in use, from the power source via the bypass line to all of the one or more sodium-ion cells.
Preferably, the method further comprises providing one or more input terminals connected to the second current path, which are typically connectable to an output of the power source. Ideally, the charging circuit is therefore so configured that in use current flows from the one or more input terminals via the second current path to all of the one or more sodium-ion cells.
Preferably, the energy storage device further includes a power source. The power source is ideally a DC power source. Preferably, the power source is a photovoltaic power source.
Preferably, the method of steps b) to e) further comprise: b) associating or integrating the energy storage device with a first power source and a second power source, in which the first power source is associated or integrated with the energy storage device prior to step c), and in which the second power source is associated or integrated with the energy storage device either prior to, or after, step c); c) directly or indirectly providing a first current path having a first conductor to transmit power from the first power source to all of the one or more sodium-ion cells to, in use, increase a first cell potential of all of the one or more sodium-ion cells to a second cell potential that can operate the one or more battery management systems; d) directly or indirectly providing a second current path having a second conductor to transmit power from the second power source to all of the one or more sodium-ion cells, in which the second current path includes all of the one or more battery management systems; and e) in response to the operation of all of the one or more battery management systems, in use, providing current flow from the second power source via the second current path to all of the one or more sodium-ion cells to increase the second cell potential of all of the one or more sodium-ion cells to a third cell potential; and in which the first current path bypasses all of the one or more battery management systems in the second current path to pass a current from the first power source via the first current path to all of the one or more sodium-ion cells.
Again, because the first current path bypasses all of the one or more battery management systems in the second current path, the cell potential of all of the one or more sodium-ion cells can be increased from a first cell potential that is not able to operate the one or more battery management systems (e.g., OV) to a second cell potential that can operate the one or more battery management systems (e.g., 1.2V or greater). Consequently, the battery management system can then be operated to enable further charging of the energy storage device via the second current path, for instance by using an external DC power source, which is preferably a photovoltaic power source.
Preferably, the method further comprises providing a switch in the first current path which is connectable with the first power source. Ideally therefore step c) comprises directly or indirectly activating the first switch (i.e., switching it 'ON') to pass a current via the first current path from the first power source to all of the one or more sodium-ion cells. The use of a switch which is connectable with the first power source advantageously allows the first power source to be selectively switched ON and OFF as appropriate at the discretion of a user. For instance, it may be desirable to keep all of the one or more sodium-ion cells at 0 volts or close to 0 volts during storage and/or transportation, and/or during a maintenance operation, but then increase the cell potential after such an event has occurred at the discretion of a user.
Preferably, the method further comprises providing one or more input terminals connected to the first current path. Ideally, these are connectable to an output of the first power source. Preferably therefore step c) comprises using the one or more input terminals such that current flows from the one or more input terminals via the first current path to all of the one or more sodium-ion cells. The use of one or more input terminals, ideally two or more input terminals, enables better user interaction with the energy storage device and allows an output of a power source to be easily connectable with the energy storage device. Preferably, the one or more input terminals comprises an IEC connector. Alternatively, the one or more input terminals may comprise two single pole connectors, one positive connector, and one negative connector. A specific example may include Amphenol RADSOK®.
Preferably, the method further comprises providing a first current path which includes one or more current limiting elements such as a diode, a MOSFET or a DC/DC convertor transistor ideally operating in the linear region.
Preferably, the one or more input terminals are connected to the first current path via one or more current limiting elements such as a diode, a MOSFET or a transistor ideally operating in the linear region. Highly preferably, the current limiting element is a diode.
Preferably, the method further comprises providing an output device that provides an indication that all of the one or more sodium-ion cells are at a cell potential of less than 1.2V, ideally less than 1.0V, most ideally at a cell potential of OV or close to OV (e.g. ± 0.5V).
Optionally, step c) of the method of the present invention does not occur unless an indication has been provided by the output device that all of the one or more sodium-ion cells are at cell potential of OV or close to OV. An indication in this context is dependent upon how the device is powered as discussed below.
The use of an output device is advantageous because it ensures that all of the one or more sodium-ion cells are easily verifiable at a certain cell potential (e.g., OV or close to OV) which may be important during storage and/or transportation, and/or during a maintenance operation. More particularly, UN shipping regulations of sodium-ion cells suggest that under certain conditions it will be a requirement that such cells do not contain any electrical energy, and this should be easily verifiable. Therefore, it is desirable that the output device maybe a visual output device, such as a bulb or a light-emitting diode (LED). Ideally, when powered from the first power source the visual output device would be illuminated. Alternatively, when powered from all of the one or more sodium-ion cells, the visual output device would not be illuminated.
In one embodiment the output device is connectable with the power source, such as the first power source. Alternatively, the output device is connectable with all of the one or more sodium-ion cells.
Preferably, the method further comprises providing a first power source. This is typically connected to all of the one or more sodium-ion cells, preferably via one or more current limiting elements such as a diode, a resistor, a MOSFET or a transistor ideally operating in the linear region. The use of one or more current limiting elements allows for current limitation from the first power source to all of the one or more sodium-ion cells.
Preferably, the first power source comprises one or more batteries, ideally non-rechargeable batteries. These may be lead-acid or silver-zinc or lithium-iron disulphide or alkaline batteries such as those known in the prior art. An AA (LR6) battery pack is one example. Ideally, the first power source is a portable power source.
By providing the energy storage device with a first power source that comprises one or more batteries this advantageously permits an increase of a first cell potential of all of the one or more sodium-ion cells connected in series to a second cell potential that can operate all of the one or more battery management systems.
Preferably, the method further comprises providing an energy storage device comprising a housing, and ideally the first power source is enclosed within the housing of the energy storage device. That is, the first power source is preferably contained within the same housing as the energy storage device of the present invention. As such, this provides a more user-friendly charging experience and saves time connecting the energy storage device to an accompanying separate power source.
Preferably, the first power source comprises one or more primary electrochemical cells. Primary electrochemical cells in this context means electrochemical cells which are non-rechargeable.
In one embodiment, all of the one or more sodium-ion cells are at a first cell potential of less than 1.2V, ideally less than 1.0V, more ideally less than 0.5V. That is, in one embodiment the first cell potential is a cell potential of less than 1.2V, ideally less than 1.0V, and more ideally less than 0.5V.
In one embodiment, all of the one or more sodium-ion cells are at a first cell potential from about -2.5V to about -0.5V. That is, in one embodiment the first cell potential is a cell potential from about -2.5V to about -0.5V.
In one embodiment, all of the one or more sodium-ion cells are at a first cell potential from about OV to about -0.5V. That is, in one embodiment the first cell potential is a cell potential from about OV to about -0.5V.
In one embodiment, all of the one or more sodium-ion cells are at a first cell potential of about OV to about 0.5V, and ideally about OV. That is, in embodiment the first cell potential is a cell potential from about OV to about 0.5V, and ideally about OV.
Preferably, the energy storage device is combined or integral with a portable power source.
Preferably, all of the one or more battery management systems in the second current path will not facilitate the second current path at a cell potential of less than the lower operating voltage of a commercially available low power microcontroller. The lower limit of a typical commercially available low power microcontroller is 1.8V, in some cases 1.2V, or in further cases 1.0V. That is, all of the one or more battery management systems will not permit current flow from the second power source to all of the one or more sodium-ion cells at a cell potential of less than 1.2V (e.g., OV), or optionally less than 1.0V.
Thus, preferably, all of the one or more battery management systems in the second current path will not facilitate the second current path at a cell potential of less than 1.2V, or optionally less than 1.0V.
Indeed, in a contemporary typical Commercial Off The Shelf (COTS) battery management system, a voltage of -1.0V or greater is required to operate the battery management system because of the intrinsic requirements of microcontrollers and MOSFETS. Thus, when all of the one or more sodium-ion cells have a cell potential of less than 1.2V (optionally less than 1.0V), the battery management system is not able to operate.
Preferably, the energy storage device comprises a second power source.
Preferably, the second power source is a DC power source, ideally a photovoltaic power source.
The energy storage device of the method of the present invention is preferably a sodium-ion battery pack or a sodium-ion battery module.
The present invention also provides, in another aspect, an energy storage device that has been charged according to the method as described herein. That is, a charged energy storage device.
The present invention also provides, in another aspect an energy storage device for use with a power source, the energy storage device comprising: one or more supercapacitors; one or more battery management systems connected to all of the one or more supercapacitors; and a charging circuit connected to all of the one or more supercapacitors and all of the one or more battery management systems, the charging circuit being configured to: (a) directly or indirectly provide a first current path having a first conductor to transmit power from the power source to all of the one or more supercapacitors to, in use, increase a first cell potential of all of the one or more supercapacitors to a second cell potential that can operate all of the one or more battery management systems; (b) directly or indirectly provide a second current path having a second conductor to transmit power from the power source to all of the one or more supercapacitors in which the second current path includes all of the one or more battery management systems; and (c) in response to the operation of all of the one or more battery management systems, in use, provide current flow from the power source via the second current to all of the one or more supercapacitors to increase the second cell potential of all of the one or more supercapacitors to a third cell potential; and in which the first current path bypasses all of the one or more battery management systems in the second current path to pass a current from the power source via the first current path to all of the one or more supercapacitors.
The preferred features described above with respect to the embodiments comprising one or more sodium-ion cells equally apply to the embodiment above comprising one or more supercapacitors.
The present invention also provides, in another aspect, a charging circuit for use with a power source and an energy storage device comprising one or more sodium-ion cells, one or more battery management systems connected to all of the one or more sodium-ion cells, the charging circuit being connectable to all of the one or more sodium-ion cells and all of the one or more battery management systems, and the charging circuit being configured to: (a) directly or indirectly provide a first current path having a first conductor to transmit power from the power source to all of the one or more sodium-ion cells to, in use, increase a first cell potential of all of the one or more sodium-ion cells to a second cell potential that can operate all of the one or more battery management systems; (b) directly or indirectly provide a second current path having a second conductor to transmit power from the power source to all of the one or more sodium-ion cells, in which the second current path includes all of the one or more battery management systems; and (c) in response to the operation of all of the one or more battery management systems, in use, provide current flow from the power source via the second current path to all of the one or more sodium-ion cells to increase the second cell potential of all of the one or more sodium-ion cells to a third cell potential; and in which the first current path bypasses all of the one or more battery management systems in the second current path to pass a current from the power source via the first current path to all of the one or more sodium-ion cells.
Similarly, the preferred features described above with respect to the embodiments comprising one or more sodium-ion cells equally apply to this embodiment relating to the charging circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described with reference to the following figures in which: Figure 1 shows an energy storage device according to the present invention; Figure 2 shows a circuit diagram of a first current path and a second current path according to a first embodiment of the present invention using two external power sources with a battery management system having a switch in a position which prevents the flow of current in the second current path; Figure 3 shows a circuit diagram of a first current path and a second current path according to the first embodiment of the present invention using two external power sources with a battery management system having a switch in a position which enables the flow of current in the second current path; Figure 4 shows a circuit diagram of a first current path using an internal power source according to a second embodiment of the present invention with a switch in a position which prevents the flow of current in the first current path; Figure 5 shows a circuit diagram of a first current path using an internal power source according to a second embodiment of the present invention with a switch in a position which allows the flow of current in the first current path; Figure 6 shows a circuit diagram of a first current path and a second current path according to a third embodiment of the present invention using one single external power source with a battery management system having a switch in a position which prevents the flow of current in the second current path; Figure 7 shows a circuit diagram of a first current path and a second current path according to a third embodiment of the present invention using one single external power source with a battery management system having a switch in a position which enables the flow of current in the second current path; Figure 8 shows a circuit diagram of a first current path and a second current path according to a fourth embodiment of the present invention using one single external power source with a battery management system having a switch in a position which prevents the flow of current in the second current path; Figure 9 shows a circuit diagram of a first current path and a second current path according to a fourth embodiment of the present invention using one single external power source with a battery management system having a switch in a position which enables the flow of current in the second current path; and Fig 10 shows a circuit diagram of a first current path and a second current path according to a fifth embodiment of the present invention using one single external power source as well as additional electrical components provided to a bypass line.
DETAILED DESCRIPTION
General structure of the device Referring to Figure 1, an energy storage device 10 for use with a power source 28, 42, 46, 54 is shown having a housing 11. Figure 1 does not show the power sources 28, 42, 46, 54. These, are instead, represented schematically in the circuit diagrams of Figures 2 to 10.
As shown in Figure 1, the housing 11 of the energy storage device 10 has a generally rectangular shape. The housing 11 comprises a front panel 12, a rear panel 14 (not shown), two side panels 16, 18 (only one side shown), a base panel 19 (not shown) and a roof panel 21. The front panel 12 and rear panel 14 are shorter in length than the two side panels 16, 18. Two handles 17 to margins of the front panel 12 are provided to permit easy movement of the energy storage device 10.
The front panel 12 is also provided with a negative terminal 13 and a positive terminal 15 which are discussed in further detail below. These permit the input of power into the energy device 10 and are represented schematically as a pair of input terminals 37a and 37b; and/or a pair of input terminals 31a and 31b; and/or a pair of input terminals 68a and 68b, in the circuit diagrams of Figure 2 to 10. The negative terminal 13 and the positive terminal 15 may comprise 2 x single pole high power connectors (e.g., Amphenol RADSOK®).
The housing 11 as shown in Figure 1 is a 19 inch, 4U, rack unit which is commonplace in the art. Enclosed within the housing 11 is one or more sodium-ion cells 20 which take the form of one or more electrochemical cells. As well as a connection to a negative input terminal 13 and a connection to a positive input terminal 15 provided to the front panel 12, the housing 11 also encloses one or more battery management systems 22 and an associated charging circuit 24 as described in detail below. The one or more battery management systems 22 may be conveniently attached to the inside of the front panel 12 to save space.
In one embodiment, with reference to Figures 4 and 5, enclosed within the housing 11 is a first power source 46. The first power source 46 ideally takes the form of a primary battery pack for example an AA ( LR6) cell. Such a battery pack is considered as portable in the art. In an alternative embodiment, with reference to Figures 2 and 3, the first power source 28 is external to the housing 11, in which case the first power source 28 is associated or integrated with the energy storage device via the negative terminal 13 and the positive terminal 15. These are shown as a pair of input terminals 37a and 37b in Figure 2.
The front panel 12 may also be provided with a switch 52 (not shown in Figure 1) which is described in further detail below with reference to Figures 4 and 5. The switch 52 in this embodiment controls current flow from the first power source 46.
Finally, the front panel 12 may also be provided with an output device 82 (not shown in Figure 1). This output device 82 (such an LED or bulb) provides an indication that all of the one or more sodium-ion cells 20 are at a certain cell potential (e.g., OV or close to OV), which is a requirement of UN shipping regulations under certain conditions. When used in combination with the embodiment described with reference to Figures 4 and 5, the output device 82 may be powered by the first power source 46 and thus have its own associated circuitry (not shown). Alternatively, the output device 82 may be powered by all of the one or more sodium-ion cells 20, and thus have its own associated circuitry (not shown). When powered from the first power source 46 the output device 82 would be illuminated at OV or close to OV. Alternatively, when powered from all of the one or more sodium-ion cells 20, the output device 82 would not be illuminated at OV or close to OV.
Embodiment that uses two different power sources (both external) Referring now to Figure 2 which illustrates a circuit diagram of a first current path 32 and second current path 36, which form part of the charging circuit 24 of the energy storage device 10.
As shown, the first current path 32 comprises a first conductor 34 having a positive and a negative conductor in the form of conductors 35a, 35b, 35c, 35d, 35e. As shown, wires 35a, 35b and 35c act as a positive conductor and wires 35d and 35e act as a negative conductor. These conductors 35a, 35b, 35c, 35d, 35e conned, via terminals 37a, 37b to a first power source 28, and at the other end, to all of the one or more sodium-ion cells 20. The first power source 28 in this embodiment is an external DC power source. Therefore, the first power source 28 connects to the first current path 32 via input terminals 37a, 37b such that in use current flows from the input terminals 37a, 37b via the first current path 32 using conductors 35a, 35b, 35c, 35d, 35e to the one or more sodium-ion cells 20. As also shown, the input terminal 37a connects to the first current path 32 using a diode 30 such that in use current flows through the diode 30 to the one or more sodium-ion cells 20. The diode 30 is positioned in the positive conductor in which one end of the diode 30 is connected with all of the one or more sodium-ion cells 20 using conductors 35b and 35c, and the other end of the diode 30 is connected with the first power source 28 via wire 35a.
The use of a diode 30 is beneficial if the first power source 28 is connected with all of the one or more sodium-ion cells 20 via terminals which can be inadvertently connected incorrectly. The input terminals 37a, 37b are connected with output terminals 39a, 39b of the first power source 28 using positive and negative electrical conductors as shown in Figure 2.
The first current path 32 is an electrical current path which permits the transfer of electrical energy to the one or more sodium-ion cells 20 when all of the one or more sodium-ion cells have an average cell potential of less than -1.2V, or in some cases, less than 1.0V. As shown in Figure 2, the first current path 32 does not include any battery management systems 22.
Thus, when all of the one or more sodium-ion cells 20 are at a first cell potential of OV (e.g., upon arrival at a customer location after transportation of the energy storage device 10), the conductor 34 permits the transfer of electrical energy from the first power source 28 to all of the one or more sodium-ion cells 20 to enable the first cell potential of OV to increase to a second cell potential which can operate the one or more battery management systems 22.
This second cell potential is typically 1.2V or greater because typically the one or more battery management systems 22 cannot operate at average cell potentials of less than 1.2V.
The absence of any battery management systems 22 in the first current path 32 enables the first current path 32 to bypass all of the one or more battery management systems 22, which are instead, present in the second current path 36. Therefore, a current can pass from the first power source 28 via the first current path 32 to all of the one or more sodium-ion cells 20 without needing any of the one or more battery management systems 22 to be in operation. That is, electrical energy can be supplied to all of the one or more sodium-ion cells 20 when the sodium-ion cells 20 are at an average first cell potential of less than 1.2V (e.g., OV) and the battery management systems 22 in the second current path 36 cannot operate.
As shown in Figure 2, the second current path 36 comprises a second conductor 38 having a positive and negative conductor in the form of conductors 40a, 40b, 40c, 35c, 35d. As shown, conductors 40a, 40b and 35c act as a positive conductor and conductors 40c and 35d act as a negative conductor. Conductors 35c and 35d to the one or more sodium-ion cells 20 may be common to both the first current path 32 and the second current path 36 as would be clear to the skilled person. Conductors 40a, 40b, 40c, 35c, 35d, connect, at one end, to a second power source 42, and at the other end, to all of the one or more sodium-ion cells 20 via a battery management system 22. The battery management system 22 is positioned in the path of the positive conductor in which one end of the battery management system 22 is connected with all of the one or more sodium-ion cells 20 using wires 40a and 35c, and the other end of the battery management system 22 is connected with the first power source 28 via wire 40b.
The battery management system 22 controls an electrically operated switch 23 to isolate all of the one or more sodium-ion cells 20. In Figure 2, the battery management system 22 is shown with its switch 23 in the open position, meaning that all of the one or more sodium-ion cells 20 are isolated from the second power source 42.
The second power source 42 is an external DC power source, such as a photovoltaic source. Therefore, the second power source 42 connects to the second current path 36 via input terminals 31a, 31b such that in use current flows from the input terminals 31a, 31b via the second current path 36 using conductors 40a, 40b, 40c, 35c, 35d to all of the one or more sodium-ion cells 20. The input terminal 31a to connects to the second current path 36 via the battery management system 22 such that when the switch 23 in the battery management system 22 is closed, in use, current flows through the battery management system 22 from the second power source 42 to all of the one or more sodium-ion cells 20.
Figure 3 shows a duplicate version of Figure 2 but illustrating the switch 23 in the battery management system 22 in a closed position. Thus, this enables current flow through the battery management system 22 from the second power source 42 to all of the one or more sodium-ion cells 20. The input terminals 31a, 31b are connected with output terminals 41a, 41b of the second power source 42 using electrical conductors as shown in Figure 2.
The second current path 36 is an electrical current path with permits the transfer of electrical energy to all of the one or more sodium-ion cells 20 when all of the one or more sodium-ion cells 20 have, for example, an average cell potential of 1.2V or greater. As shown in Figures 2 and 3, the second current path 36 includes a battery management system 22.
When all of the one or more sodium-ion cells 20 are at a first cell potential of OV (e.g., upon arrival at a customer location after transportation of the energy storage device 10), the battery management system 22 is not able to activate the switch 23 (i.e. move it from open to closed) to permit current to flow from the second power source 42 to all of the one or more sodium-ion cells 20. That is, all of the one or more the battery management systems 22 will not facilitate current flow from the second power source 42 to all of the one or more sodium-ion cells 20 when all of the one or more sodium-ion cells 20 are at a first cell potential of less than 1.2V (e.g., OV). This is shown in Figure 2 because the switch 23 is in the open position, meaning that all of the one or more sodium-ion cells 20 are isolated from the second power source 42.
Therefore, in the present invention, the first current path 32 enables electrical energy to move from the first power source 28 to all of the one or more sodium-ion cells 20 via the first current path 32. In particular, because all of the one or more the battery management systems 22 are bypassed in the first current path 32, this permits the first cell potential (e.g., OV) of all of one or more sodium-ion cells 20 to increase to a second cell potential (typically 1.2V or greater) which can then operate all of the one or more battery management systems 22 in the second current path 36. Then, in response to the operation of all of the one or more battery management systems 22, the switch 23 can move from its open position (Figure 2) to a closed position (Figure 3), such that current is then able to flow from the second power source 42 to all of the one or more sodium-ion cells 20 to increase the second cell potential of all of the one or more sodium-ion cells to a third cell potential. The third cell potential is greater than the second cell potential, and typically is -2.85V, which is a typical minimum operating voltage of a commercial inverter.
Embodiment that uses two different power sources (one internal; one external) A further embodiment of the present invention is now described. In this embodiment, the first power source is an internal DC power source in contrast to an external DC power source as described above with reference to Figures 2 and 3.
Referring now to Figure 4 which illustrates a circuit diagram of an alternative first current path 44, which uses an internal battery as a first power source 46. The charging circuit 24 and first power source 46 are enclosed within the housing 11 of the energy storage device 10 as shown in Figure 4. As shown, the first current path 44 comprises a first conductor 47 having a positive conductor and a negative conductor in the form of electrical conductors 48a, 48b, 48c, 48d, 48e, 48f. As shown, 48a, 48b, 48d, 48e act as a positive conductor and 48c and 48f act as a negative conductor. These conductors 48a, 48b, 48c, 48d, 48e, 48f connect the first power source 46 to all of the one or more sodium-ion cells 20. As set out above, in this embodiment, the first power source 46 is internal DC power source.
Therefore, the first power source 46 connects to the first current path 44 such that in use current flows to all of the one or more sodium-ion cells 20 using conductors 48a, 48b, 48c, 48d, 48e, 48f. As also shown, the first power source 46 connects to all of the one or more sodium-ion cells 20 via a resistor 50 and a switch 52. The switch 52 can move between an open position (Figure 4) and a closed position (Figure 5). Thus, when the switch 52 is activated (i.e., it is switched 'ON' -as per Figure 5), current flows, in use, from the first power source 46 via the first current path 44 comprising a resistor 50, to all of the one or more sodium-ion cells 20. The switch 52 can be operated by a user of the energy storage device 10.
The first current path 44 is an electrical current path which permits the transfer of electrical energy to all of the one or more sodium-ion cells 20 when all of the one or more sodium-ion cells 20 have, for example, an average cell potential of less than 1.2V. As shown in Figures 4 and 5, the first current path 44 does not include any battery management systems 22. Thus, when the sodium-ion cells 20 are at a first cell potential of OV (e.g., upon arrival at a customer location after transportation of the energy storage device 10), and the switch 52 is turned ON by a user of the energy storage device 10, electrical energy is transferred from the first power source 46 to all of the one or more sodium-ion cells 20 to enable the first cell potential of OV to increase to a second cell potential which can operate the one or more battery management systems 22. This second cell potential is typically 1.2V or greater because typically all of the one or more battery management systems 22 cannot operate at average cell potentials of less than 1.2V.
The absence of any battery management systems 22 in the first current path 44 enables the first current path 44 to bypass all of the one or more battery management systems 22, which are instead, present in the second current path 36. Therefore, a current can pass from the first power source 46 via the first current path 44 to all of the one or more sodium-ion cells 20 without needing any of the one or more battery management systems 22 to be in operation. That is, electrical energy can be supplied to all of the one or more sodium-ion cells 20 when the all of the one or more sodium-ion cells 20 are at an average first cell potential of less than 1.2V (e.g., OV) and the battery management systems 22 in the second current path 36 cannot operate.
The second current path 36 in this embodiment with reference to Figures 4 and 5 is the same as the second current path 36 in the embodiment described above with reference to Figures 2 and 3. In particular, because all of the one or more the battery management systems 22 are bypassed in the first current path 44, this permits the first cell potential (e.g., OV) of all of the one or more sodium-ion cells 20 to increase to a second cell potential (typically 1.2V or greater) which can then operate all of the one or more battery management systems 22 in the second current path 36. Then, in response to the operation of all of the one or more battery management systems 22, the switch 23 can move from its open position (Figure 2) to a closed position (Figure 3)), such that current is then able to flow from the second power source 42 to all of the one or more sodium-ion cells 20 to increase the second cell potential of all of the one or more sodium-ion cells to a third cell potential. The third cell potential is greater than the second cell potential, and typically is -2.85V, which is the minimum operating voltage of a commercial inverter.
Embodiment that uses one power source A further embodiment of the present invention is now described. In this embodiment, a single power source 54 is used to charge the energy storage device 10, compared to two different power sources as described with reference to Figures 2 to 5. Referring now to Figure 6 which illustrates a circuit diagram of a first current path 56 and a second current path 58, which form part of the charging circuit 24 of the energy storage device 10.
The first current path 56 comprises a first conductor 60 having a positive and a negative conductor in the form of conductors 62a, 62b, 66a. As shown, conductor 66a acts as a positive conductor and conductors 62a and 62b act as a negative conductor. In use, the first conductor 60 permits power to be transferred from the power source 54 to all of the one or more sodium-ion cells 20. In this embodiment, the power source 54 is an external DC power source such as a photovoltaic power source (i.e., external to the housing 11 of the energy storage device 10). The first current path 56 and the second current path 58 each use the same power source 54. Thus, a common (i.e. shared) positive conductor 66a from the power source 54 is used for the first current path 56 and the second current path 58.
The second current path 58 comprises a second conductor 64 having a positive and a negative conductor in the form of electrical conductors 66a, 66b, 66c, 66d. As shown, conductor 66a acts as a positive conductor and conductors 66b, 66c and 66d act as a negative conductor. Conductors 66b and 66a to the one or more sodium-ion cells 20 may be common to both the first current path 32 and the second current path 36 as would be clear to the skilled person. In use, the second conductor 64 permits power to be transferred from the power source 54 to all of the one or more sodium-ion cells 20. As shown by Figure 7, the second current path 58 connects the power source 54 to all of the one or more sodium-ion cells 20 via a battery management system 22.
The battery management system 22 is positioned in the path of the negative conductor 66d and 66c in which one end of the battery management system 22 is connected with all of the one or more sodium-ion cells 20 using conductor 66d, and the other end of the battery management system 22 is connected with the power source 54 via conductor 66c. The battery management system 22 controls an electrically operated switch 23 to isolate all of the one or more sodium-ion cells 20. In Figure 6, the battery management system 20 is shown with its switch 23 in the open position, meaning that all of the one or more sodium-ion cells 20 are isolated from the power source 54 via the second current path 58.
The power source 54 in this embodiment is an external DC power source, such as a photovoltaic source, and its current is shared between the first current path 56 and the second current path 58. Therefore, the power source 54 connects to the first current path 56 and second current path 58 via input terminals 68a, 68b such that in use current flows from the input terminals 68a, 68b via the first current path 56 or the second current path 58 (when the switch 53 is closed) to all of the one or more sodium-ion cells 20. The input terminals 68a, 68b are connected to output terminals 70a, 70b of the power source 54 using electrical conductors as shown in Figure 6.
The first current path 56 is connected with the second current path 58 via two electrical connections 72a, 72b to form bypass line 74 to bypass the battery management system 22 in the second current path 58. Thus, one end 74a of the bypass line 74 is connected with the second current path 58 on one side of the battery management system 22 and the other end 74b of the bypass line 74 is connected with the second current path 58 on the other side of the battery management system 22. This bypass line 74 includes a current limiting diode 76.
The first current path 56 is an electrical current path which permits the transfer of electrical energy to all of the one or more sodium-ion cells 20 when all of the one or more sodium-ion cells have an average cell potential of less than 1.2V. As shown in Figure 6, the first current path 56 as the bypass line 74 does not include any battery management systems 22.
Thus, when all of the one or more sodium-ion cells 20 are at a first cell potential of OV (e.g., upon arrival at a customer location after transportation of the energy storage device 10), the conductor 60 permits the transfer of electrical energy from the power source 54 using the bypass line 74 to all of the one or more sodium-ion cells 20 to enable the first cell potential of OV to increase to a second cell potential which can operate the one or more battery management systems 22. This second cell potential is typically 1.2V or greater because all of the one or more battery management systems 22 cannot typically operate at average cell potentials of less than 1.2V.
The absence of any battery management systems 22 in the first current path 56 enables the first current path 56 to bypass all of the one or more battery management systems 22, which are instead, present in the second current path 58. Therefore, a current can pass from the power source 54 via the first current path 56 to all of the one or more sodium-ion cells 20 without needing any of the one or more battery management systems 22 to be in operation. That is, electrical energy can be supplied to all of the one or more sodium-ion cells 20 when all of the one or more sodium-ion cells 20 are, for example, at an average first cell potential of less than 1.2V (e.g., OV) and the battery management systems 22 in the second current path 58 cannot operate.
The battery management system 22 controls an electrically operated switch 23 to isolate all of the one or more sodium-ion cells 20. In Figure 6, the battery management system 22 is shown with its switch 23 in the open position, meaning that all of the one or more sodium-ion cells 20 are isolated from the power source 54 via the second current path 58. Figure 7 shows a duplicate version of Figure 6 but showing the switch 23 in the battery management system 22 in a closed position. Thus, when the switch 23 is in a closed position this enables current flow via the second current path 58 through the battery management system 22 from the power source 54 to all of the one or more sodium-ion cells 20. As will be described below, the second current path 58 is an electrical current path which permits the transfer of electrical energy to the one or more sodium-ion cells 20 when all of the one or more sodium-ion cells have, for example, an average cell potential of 1.2V or greater.
In particular, when all of the one or more sodium-ion cells 20 are at a first cell potential of OV (e.g., upon arrival at a customer location after transportation of the energy storage device 10), the battery management system 22 is not able to deactivate the switch 23 (i.e. move it from open to closed) to permit current to flow from the second power source 42 to all of the one or more sodium-ion cells 20. That is, all of the one or more the battery management systems 22 will not facilitate current flow from the power source 54 via the second current path 58 to all of the one or more sodium-ion cells 20 when all of the one or more sodium-ion cells 20 are at a first cell potential of, for example, less than 1.2V (e.g., DV). This is shown in Figure 6 because the switch 23 is in the open position, meaning that all of the one or more sodium-ion cells 20 are isolated from the power source 54 via the second current path.
Therefore, in the present invention, the first current path 56 enables electrical energy to move from the power source 54 to all of the one or more sodium-ion cells 20 via the first current path 56. In particular, because all of the one or more the battery management systems 22 are bypassed in the first current path 56, this permits the first cell potential (e.g., OV) of all of the one or more sodium-ion cells 20 to increase to a second cell potential (typically 1.2V or greater) which can then operate all of the one or more battery management systems 22 in the second current path 58. Then, in response to the operation of all of the one or more battery management systems 22, the switch 23 can move to from its open position (Figure 6) to a closed position (Figure 7)), such that current is then able to flow current flow from the power source 54 via the second current path 58 to all of the one or more sodium-ion cells 20 to increase the second cell potential of all of the one or more sodium-ion cells to a third cell potential. The third cell potential is greater than the second cell potential, and typically is -2.85V, which is the minimum operating voltage of a commercial inverter.
Embodiment that uses one power source (including an internal DC / DC convertor) This embodiment is identical to the embodiment described with reference to Figures 6 and 7 above with the exception that the diode 76 in the bypass line 74 of the first current path 56 has been replaced with a DC / DC voltage converter 78, as shown with reference to Figures 8 and 9. The DC / DC convertor 78 additionally requires a connection to the negative conductor of the second current path 58 as shown by the negative conductor 80 in Figures 8 and 9. The DC / DC converter 78 converts a voltage of the power source 54 to a voltage that is suitable to charge the energy storage device 10 via the first current path 56.
In Figure 8, the battery management system 22 is shown with its switch 23 in the open position, meaning that all of the one or more sodium-ion cells 20 are isolated from the power source 54 via the second current path 58. Figure 9 shows a duplicate version of Figure 8 but showing the switch 23 in the battery management system 22 in a closed position. Thus, when the switch 23 is in a closed position this enables current flow via the second current path 58 through the battery management system 22 from the power source 54 to all of the one or more sodium-ion cells 20.
Embodiment that uses one power source (including an additional protection device) A final embodiment of the present invention is now described with reference to Figure 10.
This embodiment includes both a diode 76 and a DC/DC convertor 78 in the bypass line 74 of the first current path 56. As in Figures 8 and 9, the DC/DC convertor 78 additionally requires a connection to the negative conductor of the second current path 58 as shown by the negative conductor 80 in Figure 10. Additionally, the first current path 56 comprises a current overload device 81, which can preferably be a resettable fuse or more preferably be an active protection to protect the devices and conductors from high inrush currents and/or overcurrents. A switch 52 is used in this path 56 as an additional control measure to disconnect the bypass line 74.
Method of the present invention A method of charging an energy storage device 10 from an average cell voltage of OV is now described in the scenario of installing the energy storage device 10 for the first time after transporting the device 10 to a location for use.
An energy storage device 10 as described in the embodiment of Figures 4 and 5 is provided. Furthermore, all of the one or more sodium-ion cells in the energy storage device 10 are at an average first cell potential of OV. The energy storage device 10 also includes within its housing 11 an LR6 battery pack as a first power source 46. Upon installation, the device is connected to a second power source 42 via input terminal 31a, 31b. Because all of the one or more sodium-ion cells in the energy storage device 10 are at a first average cell potential of OV, the output device 82 as an LED on the front panel 12 provides a visual indication of this to the installer. As such, the installer is prompted to turn switch 52 ON' to begin a two-stage charging process of all of the one or more sodium-ion cells in the energy storage device 10.
By turning switch 52 'ON', this causes current to pass from the first power source 46 via a first current path 44 to all of the one or more sodium-ion cells 20. Importantly, the first current path 44 bypasses all of the one or more battery management systems 22 in the second current path 36 because the first current path 44 is separate (i.e., distinct) from the second current path 36. As such, turning switch 52 'ON', increases a first average cell potential of OV of all of the one or more sodium-ion cells 20 to a second cell potential of above 1.2V, which can then operate the one or more battery management systems 20.
As this point, because the one or more battery management systems 20 can now operate, and current can flow from the second power source 42 to all of the one or more sodium-ion cells 20 via the second current path 36 to increase the second cell potential of all of the one or more sodium-ion cells to a third cell potential. Photovoltaic energy as the second power source 42 is then stored in the energy storage device 10.
For embodiments 6-9, when the power source 54 and all of the one or more sodium-ion cells 20 are at different voltages, an undesirable high current may flow upon direct connection. Thus, the bypass path 74, can include current regulating devices (e.g. 76) to transfer energy from the power source 54 to the energy storage device 10, to raise the voltage of all of the one or more sodium-ion cells 20. These current regulation devices, function as a variable impedance path between 20 and 54 to limit the flow of current. Once all of the one or more sodium ion cells 20 reach a cell potential at which the BMS 22 can start operation, it will close the switch 23 to connect the DC source 54 to store energy in energy storage device 20 via path 58.
The embodiment in Figure 10 requires an operation of a switch 52, which when closed will allow current to pass through conductor 74 to all of the one or more sodium-ion cells 20, initially via diode 76. For high capacity energy storage devices, the current limiting device 76, operating in a linear mode may undesirably consume (i.e., waste a lot of) energy, and the energy storage device 10 may take a long period of time to achieve a cell potential at which the BMS 22 can operate. A DC/DC converter 78, provided in the first current path 56, can act as a high efficiency current regulator to speed up this process. Once the required cell potential is achieved, the switch 23 may be activated by the BMS 22 to complete the second current path 58, and switch 52 may be used to discontinue current through the first current path 56.
The present disclosure is intended to be an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated by the figures or the specific description as set out above.
For example, whilst the use of diodes and/or DC / DC voltage converters have been demonstrated in their specific locations as described above, it could be envisaged that they could be placed elsewhere. For instance, the use of an external DC / DC voltage converter could be positioned between the output terminals of a power source and the input terminals of the energy storage device according to the present invention to enable greater compatibility with different types of power source.
Additionally, whilst the specific embodiments illustrated by the figures and the specific description as set out above utilise one or more sodium-ion cells in the energy storage device, it could be envisaged that such one or more sodium-ion cells could be replaced with one or more supercapacitors.

Claims (29)

  1. CLAIMSAn energy storage device (10) for use with a power source (28; 42; 46; 54), the energy storage device (10) comprising: one or more sodium-ion cells (20); one or more battery management systems (22) connected to all of the one or more sodium-ion cells (20); and a charging circuit (24) connected to all of the one or more sodium-ion cells (20) and all of the one or more battery management systems (22), the charging circuit (24) being configured to: (a) directly or indirectly provide a first current path (32; 44; 56) having a first conductor (34; 47; 60) to transmit power from the power source (28; 46; 54) to all of the one or more sodium-ion cells (20) to, in use, increase a first cell potential of all of the one or more sodium-ion cells (20) to a second cell potential that can operate all of the one or more battery management systems (22); (b) directly or indirectly provide a second current path (36; 58) having a second conductor (38; 64) to transmit power from the power source (42; 54) to all of the one or more sodium-ion cells (20), in which the second current path (36; 58) includes all of the one or more battery management systems (22); and (c) in response to the operation of all of the one or more battery management systems (22), in use, provide current flow from the power source (42; 54) via the second current path (36; 58) to all of the one or more sodium-ion cells (20) to increase the second cell potential of all of the one or more sodium-ion cells (20) to a third cell potential; and in which the first current path (32; 44; 56) bypasses all of the one or more battery management systems (22) in the second current path (36; 58) to pass a current from the power source (28; 46; 54) via the first current path (32; 44; 56) to all of the one or more sodium-ion cells (20).
  2. 2. The energy storage device according to claim 1, in which the first current path (56) and the second current path (58) are configured to both use the same power source (54).
  3. 3. The energy storage device according to any one of claims 1 to 2, in which the first current path (56) is connected with the second current path (58) via one or more electrical connections (72a, 72b) to form a bypass line (74) in which one end (74a) of the bypass line (74) is connected with the second current path (58) on one side of all of the one or more battery management systems (22) and the other end (74b) of the bypass line (74) is connected with the second current path (58) on the other side of all of the one or more battery management systems (22).
  4. 4. The energy storage device according to claim 3, in which the bypass line (74) further includes a device selected from the group consisting of a diode (76), a voltage convertor (78), a current overload device (81), or a combination thereof.
  5. The energy storage device according to claim 3, in which the bypass line (74) further includes a switch (52), such that when the switch (52) is activated (i.e., it is switched ON'), current flows, in use, from the power source (54) via the bypass line (74) to all of the one or more sodium-ion cells (20).
  6. 6. The energy storage device according to any one of claims 1 to 5, further comprising one or more input terminals (31a, 31b; 68a, 68b) connected to the second current path (36; 58) and connectable to an output of the power source (42; 54), and the charging circuit (24) being so configured that in use current flows from the one or more input terminals (31a, 31b; 68a, 68b) via the second current path (36; 58) to all of the one or more sodium-ion cells (20).
  7. 7. The energy storage device according to any one of claims 1 to 6, further comprising a power source (42; 54), in which the power source (42; 54) comprises a photovoltaic power source.
  8. 8. The energy storage device according to claim 1, for use with a first (28; 46) and a second power source (42), and in which the charging circuit (24) is further configured to: (a) directly or indirectly provide a first current path (32; 44) having a first conductor (34; 47) to transmit power from the first power source (28; 46) to all of the one or more sodium-ion cells (20) to, in use, increase a first cell potential of all of the one or more sodium-ion cells (20) to a second cell potential that can operate all of the one or more battery management systems (22); (b) directly or indirectly provide a second current path (36) having a second conductor (38) to transmit power from the second power source (42) to all of the one or more sodium-ion cells (20), in which the second current path (36) includes all of the one or more battery management systems (22); and (c) in response to the operation of all of the one or more battery management systems (22), in use, provide current flow from the second power source (42) via the second current path (36) to all of the one or more sodium-ion cells (20) to increase the second cell potential of all of the one or more sodium-ion cells (20) to a third cell potential; and in which the first current path (32; 44) bypasses all of the one or more battery management systems (22) in the second current path (36) to pass a current from the first power source (28; 46) via the first current path (32; 44) to all of the one or more sodium-ion cells (20).
  9. 9. The energy storage device according to claim 8, further comprising a switch (52) in the first current path (44) that is connectable with the first power source (46), and the charging circuit (24) being so configured that when the switch (52) is activated (i.e., it is switched 'ON'), current flows, in use, from the first power source (46) via the first current path (44) to all of the one or more sodium-ion cells (20).
  10. 10. The energy storage device according to any one of claims 1 to 9, further comprising an output device (82) arranged to provide an indication that all of the one or more sodium-ion cells (20) are at cell potential of OV or close to OV.
  11. 11. The energy storage device according to claim 8, further comprising one or more input terminals (37a, 37b) connected to the first current path (32) and connectable to an output of the first power source (28), and the charging circuit (24) being so configured that in use current flows from the one or more input terminals (37a, 37b) via the first current path (32) to all of the one or more sodium-ion cells (20).
  12. 12. The energy storage device according to claim 11, in which the one or more input terminals (37a, 37b) are connected to the first current path via one or more diodes (30).
  13. 13. The energy storage device according to claim 8, further comprising a first power source (46), optionally in which the first power source (46) is connected to all of the one or more sodium-ion cells (20) via one or more resistors (50).
  14. 14. The energy storage device according to claim 13, in which the first power source (46) is a power source which comprises one or more batteries.
  15. 15. The energy storage device according to any one of claims 1 to 14, in which all of the one or more sodium-ion cells (20) are at a first cell potential of less than 1.2V.
  16. 16. The energy storage device according to any one of claims 1 to 15, in which all of the one or more battery management systems (22) in the second current path (36; 58) will not facilitate the second current path (36; 58) at a cell potential of less than 1.2V.
  17. 17. The energy storage device according to any one of claims 8 to 16, further comprising a second power source (42), in which the second power source (42) is a photovoltaic power source.
  18. 18. The energy storage device according to any one of claims 1 to 17, in which the second cell potential is a cell potential of 1.0V or greater.
  19. 19. The energy storage device according to any one of claims 1 to 18, in which the third cell potential is a cell potential of 1.5V or greater.
  20. 20. A photovoltaic power source associated or integrated with an energy storage device (10) according to any one of claims 1 to 19.
  21. 21. A method of charging an energy storage device (10), the method comprising: a) providing an energy storage device (10) comprising one or more sodium-ion cells (20), one or more battery management systems (22) connected to all of the one or more sodium-ion cells (20), and a charging circuit (24) connected to all of the one or more sodium-ion cells (20) and all of the one or more battery management systems (22); b) associating or integrating the energy storage device (10) with a power source (28; 42; 46; 54); c) directly or indirectly providing a first current path (32; 44; 56) having a first conductor (34; 47; 60) to transmit power from the power source (28; 46; 54) to all of the one or more sodium-ion cells (20) to, in use, increase a first cell potential of all of the one or more sodium-ion cells (20) to a second cell potential that can operate all of the one or more battery management systems (20); d) directly or indirectly providing a second current path (36; 58) having a second conductor (38; 64) to transmit power from the power source (42; 54) to all of the one or more sodium-ion cells (20), in which the second current path (36; 58) includes all of the one or more battery management systems (22); and e) in response to the operation of all of the one or more battery management systems (22), in use, providing current flow from the power source (42; 54) via the second current path (36; 58) to all of the one or more sodium-ion cells (20) to increase the second cell potential of all of the one or more sodium-ion cells (20) to a third cell potential; and in which the first current path (32; 44; 56) bypasses all of the one or more battery management systems (22) in the second current path (36; 58) to pass a current from the power source (28; 46; 54) via the first current path (32; 44; 56) to all of the one or more sodium-ion cells (20).
  22. 22. The method according to claim 21, in which the first current path (56) and the second current path (58) are configured to both use the same power source (54).
  23. 23. The method according to claim 21, in which the first current path (56) is connected with the second current path (58) via one or more electrical connections (72a, 72b) to form a bypass line (74) in which one end (74a) of the bypass line (74) is connected with the second current path (58) on one side of all of the one or more battery management systems (22) and the other end (74b) of the bypass line (74) is connected with the second current path (58) on the other side of all of the one or more battery management systems (22).
  24. 24. The method according to claim 21, in which steps b) to e) further comprise: b) associating or integrating the energy storage device (10) with a first power source (28; 46) and a second power source (42), in which the first power source (28; 46) is associated or integrated with the energy storage device (10) prior to step c), and in which the second power source (42) is associated or integrated with the energy storage device (10) either prior to, or after, step c); c) directly or indirectly providing a first current path (32; 44) having a first conductor (34) to transmit power from the first power source (28; 46) to all of the one or more sodium-ion cells (20) to, in use, increase a first cell potential of all of the one or more sodium-ion cells (20) to a second cell potential that can operate the one or more battery management systems (20); d) directly or indirectly providing a second current path (36) having a second conductor (38) to transmit power from the second power source (42) to all of the one or more sodium-ion cells (20), in which the second current path (32) includes all of the one or more battery management systems (22); and e) in response to the operation of all of the one or more battery management systems (22), in use, providing current flow from the second power source (42) via the second current path (36) to all of the one or more sodium-ion cells (20) to increase the second cell potential of all of the one or more sodium-ion cells (20) to a third cell potential; and in which the first current path (32; 44) bypasses all of the one or more battery management systems (22) in the second current path (36) to pass a current from the first power source (28; 46) via the first current path (32) to all of the one or more sodium-ion cells (20).
  25. 25. The method according to any one of claims 21 to 24, further comprising providing an output device (82) arranged to provide an indication that all of the one or more sodium-ion cells (20) are at cell potential of OV or close to OV, and in which step c) does not occur unless an indication has been provided by the output device (82) that all of the one or more sodium-ion cells (20) are at cell potential of OV or close to OV.
  26. 26. The method according to any one of claims 21 to 25, in which all of the one or more sodium-ion cells (20) are at a first cell potential of less than 1.2V.
  27. 27. The method according to any one of claims 21 to 26, in which all of the one or more battery management systems (22) in the second current path (36; 58) will not facilitate the second current path (36; 58) at a cell potential of less than 1.2V.
  28. 28. An energy storage device which has been charged according to the method of any one of claims 21 to 27.
  29. 29. An energy storage device (10) for use with a power source (28; 42; 46; 54), the energy storage device (10) comprising: one or more supercapacitors; one or more battery management systems (22) connected to all of the one or more supercapacitors; and a charging circuit (24) connected to all of the one or more supercapacitors and all of the one or more battery management systems (22), the charging circuit (24) being configured to: (a) directly or indirectly provide a first current path (32; 44; 56) having a first conductor (34; 47; 60) to transmit power from the power source (28; 46; 54) to all of the one or more supercapacitors to, in use, increase a first cell potential of all of the one or more supercapacitors to a second cell potential that can operate all of the one or more battery management systems (22); (b) directly or indirectly provide a second current path (36; 58) having a second conductor (38; 64) to transmit power from the power source (42; 54) to all of the one or more supercapacitors in which the second current path (36; 58) includes all of the one or more battery management systems (22); and (c) in response to the operation of all of the one or more battery management systems (22), in use, provide current flow from the power source (42; 54) via the second current path (36; 58) to all of the one or more supercapacitors to increase the second cell potential of all of the one or more supercapacitors to a third cell potential; and in which the first current path (32; 44; 56) bypasses all of the one or more battery management systems (22) in the second current path (36; 58) to pass a current from the power source (28; 46; 54) via the first current path (32; 44; 56) to all of the one or more supercapacitors.
GB2318529.1A 2023-12-04 2023-12-04 Energy storage device and methods of charging Pending GB2628025A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113937865A (en) * 2021-11-24 2022-01-14 长沙新材料产业研究院有限公司 Battery management system and power supply system
CN116666788A (en) * 2023-07-31 2023-08-29 苏州融硅新能源科技有限公司 Battery pack, management method thereof and battery management system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113937865A (en) * 2021-11-24 2022-01-14 长沙新材料产业研究院有限公司 Battery management system and power supply system
CN116666788A (en) * 2023-07-31 2023-08-29 苏州融硅新能源科技有限公司 Battery pack, management method thereof and battery management system

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