Reversible electrical energy storage device, battery, storage system and associated process

Abstract

The reversible electrical energy storage device (9) comprises at least one storage branch (10) having at least two energy storage modules (16), the ends (12, 14) of the storage branch being intended to be connected to a reversible electrical energy conversion device. The device further comprises disconnectors (17) connecting each end of the branch to an energy storage module and connecting the energy storage modules together in series. Figure for the abstract: Fig 2

Description

Title of the invention: Reversible electrical energy storage device, battery, storage system and associated method

[0001] The present invention relates to the storage of electrical energy and more particularly relates to an electrical energy storage device, an electrical energy storage battery comprising one or more storage devices, a method of implementing the device and an electrical energy storage system comprising the battery.

[0002] Generally, an electrical energy storage system comprises an electrical power converter connected to a low voltage battery, i.e. the voltage at the terminals of the battery is less than 1500 volts DC.

[0003] The power converter made from semiconductor switches generally delivers the electrical power contained in the battery to a power bus supplying, for example, ship engines.

[0004] According to another mode of operation, the power converter can recharge the battery from the power bus.

[0005] An intervention on the low voltage battery does not require medium or high voltage approval, in particular for the consignment, maintenance or replacement of the batteries.

[0006] In addition, there are protective devices such as circuit breakers configured to protect the low voltage battery during a fault.

[0007] To obtain a set of electrical energy storage systems capable of delivering high power, it is known to connect several electrical energy storage systems to the power bus.

[0008] When the power converter is of the inverter type, high power is, for example, a delivered power greater than 800 kVA.

[0009] When the power converter is of the chopper type, high power is, for example, a delivered power greater than 850kW.

[0010] However, since each storage system includes a power converter, it is necessary to provide a large space to accommodate the power converters.

[0011] Furthermore, the use of multiple power converters complicates the control circuit of the entire storage system and makes the entire storage system expensive.

[0012] Another known solution consists of connecting the low voltage batteries together in series in order to obtain a high voltage battery delivering high power under a voltage generally greater than 1500 volts, for example under a voltage of 5000 volts.

[0013] However, the series connection of low voltage batteries forms a medium voltage battery, having for example at its terminals a voltage of 5000 volts. The medium voltage battery belongs to the category of high voltage devices requiring medium or high voltage approval for any work on the medium voltage battery.

[0014] Furthermore, the protection devices configured to protect the low voltage batteries during a failure are not suitable for protecting the medium voltage battery.

[0015] It is therefore proposed to overcome all or part of the drawbacks linked to electrical energy storage systems delivering high power according to the state of the art, in particular to simplify and facilitate the implementation of such systems.

[0016] In view of the above, there is proposed, according to a first aspect, a reversible electrical energy storage device comprising at least one storage branch comprising at least two energy storage modules, the ends of the storage branch being intended to be connected to a reversible electrical energy conversion device.

[0017] The device further comprises disconnectors connecting each end of the branch to an energy storage module and connecting the energy storage modules together in series.

[0018] Advantageously, the device comprises at least one second storage branch connected in parallel with said storage branch.

[0019] Preferably, a secondary static cut-off device connects one of the ends of each branch to the disconnector arranged between said end of said branch and said energy storage module adjacent to said end, the secondary static cut-off device being configured to cut the connection between said end and said disconnector when a current flowing in said secondary static cut-off device is greater than a predetermined threshold secondary current or upon receipt of a command issued by control means.

[0020] Advantageously, each energy storage module comprises an electrical energy storage means and monitoring means configured to measure electrical and thermal characteristics of each energy storage means and transmit the measured values ​​to control means.

[0021] According to another aspect, there is proposed an electrical energy storage battery comprising at least two connection terminals and a reversible energy storage device as defined previously, each end of the storage branch being connected to a different connection terminal.

[0022] According to another aspect, there is proposed an electrical energy storage battery comprising at least two connection terminals and at least two reversible energy storage devices as defined previously, the energy storage devices being connected in series, the two free ends of the storage branches each being connected to a different connection terminal.

[0023] According to yet another aspect, there is proposed an electrical energy storage system comprising an electrical energy storage battery as defined previously, control means configured to control the disconnectors and a reversible electrical energy conversion device connected to the terminals of the battery, the control means being further configured to control, where appropriate, the secondary static cut-off device.

[0024] Preferably, the electrical energy storage system further comprises a primary static cut-off device connecting the reversible electrical energy conversion device to the electrical energy storage battery, the primary static cut-off device being configured to cut the connection between the battery and the reversible electrical energy conversion device when a current flowing in said primary static cut-off device is greater than a predetermined primary threshold current.

[0025] According to another aspect, there is provided a ship comprising an electrical energy storage system as defined above.

[0026] According to another aspect, there is provided a method of storing electrical energy.

[0027] The method comprises a locking step comprising the opening of disconnectors of at least one storage branch of at least one reversible electrical energy storage device, said branch comprising at least two energy storage modules and in which the disconnectors connect each end of the branch to an energy storage module and connect the energy storage modules together in series.

[0028] Preferably, the method comprises opening a primary static cut-off device connecting a reversible electrical energy conversion device to the electrical energy storage device to cut the connection between the electrical energy storage device and the electrical energy conversion device when a current flowing in said primary static cut-off device is greater than a predetermined threshold primary current.

[0029] Advantageously, the method comprises opening a secondary static cut-off device connecting one end of the branch to the disconnector arranged between said end of said branch and said energy storage module to cut the connection between said end and said disconnector when a current flowing in said secondary static cut-off device is greater than a secondary current of predetermined threshold.

[0030] Other characteristics and advantages of the invention will appear on reading the following description of embodiments of the invention, given solely as non-limiting examples and with reference to the drawings in which:

[0031] [Fig-1] illustrates an embodiment of a ship according to the invention;

[0032] [Fig.2] illustrates a first example of embodiment of a battery according to the invention;

[0033] [Fig.3] illustrates a second example of embodiment of a battery according to the invention; And

[0034] [Fig.4] illustrates an example of implementation of a storage system according to the invention.

[0035] Reference is made to [Fig.l] which illustrates an embodiment of a ship 1 comprising propulsion engines 2 comprising propellers for moving the ship 1 in the water, a power bus 3 supplying the engines 2 and a reversible electrical energy storage system 4 supplying the bus 3.

[0036] Of course, the storage system 4 can be implemented for other applications, for example to power a compressor.

[0037] The storage system 4 comprises an electrical energy storage battery 5 comprising two connection terminals 51, 52 connected to a primary static cut-off device 6.

[0038] The storage system 4 further comprises a reversible electrical energy conversion device 7 connected to the primary static device 6 and to the power bus 3.

[0039] The reversible electrical energy conversion device 7 is made from semiconductor components such as power transistors.

[0040] The primary static device 6 is made from semiconductors, and cuts the connection between the battery 5 and the conversion device 7 when a current II flowing in said device is greater than a predetermined threshold primary current.

[0041] The primary threshold current is for example equal to 2500 A for a voltage of 4000 Vdc delivered by the battery 5.

[0042] When the current II is greater than the primary threshold current, the system 4 is considered to be faulty so that the primary static device 6 makes it possible to detect the fault and protect the system 4, thus avoiding its degradation.

[0043] Alternatively, the storage system 4 does not include a primary static device 6

[0044] When the motors 2 are of the direct current motor type, the conversion device 7 comprises a chopper generating a direct current voltage from the voltage of the battery 5 to power the motors 2.

[0045] When the motors 2 are of the alternating current motor type, the conversion device 7 comprises an inverter generating a multi-phase alternating voltage at from battery voltage 5 to power motors 2.

[0046] The storage system 4 further comprises control means 8.

[0047] [Fig.2] illustrates a first example of embodiment of the battery 5

[0048] The battery 5 comprises an electrical energy storage device 9 comprising two terminals 91, 92 each connected to a different terminal 51, 52 of the battery 5.

[0049] The storage device 9 comprises two storage branches 10, 11 connected in parallel, a first end 12, 13 of the branches 10, 11 being connected to a first terminal 91 of the storage device 9, and the second end 14, 15 of the branches 10, 11 being connected to the second terminal 92 of the storage device 9.

[0050] Each branch 10, 11 comprises three identical energy storage modules 16 and disconnectors 17 connecting each end 12, 13, 14, 15 of each branch 10, 11 to a storage module 16 and connecting the storage modules 16 of the same branch 10, 11 in series.

[0051] Each storage module 16 comprises a means 18 for storing electrical energy, and monitoring means 19 measuring electrical and thermal characteristics of each storage means 18 and transmitting the measured values ​​to the control means 8.

[0052] Each storage module 16 comprises, for example, a low-voltage battery or a supercapacitor, the voltage across the storage means being equal to or less than 1500 volts DC so that each storage means is governed by the regulations relating to low-voltage storage devices.

[0053] The device 9 further comprises a secondary static cut-off device 20 connecting the first ends 12, 13 of each branch 10, 11 to the disconnector 17 arranged between the first end 12, 13 of each branch 10, 11 and the storage module 16 adjacent to the first end 12, 13.

[0054] The secondary static cut-off device 20 is made from semiconductor switches and cuts the connection between the first 12, 13 end and said disconnector 17 when a current 12 flowing in the secondary static device is greater than a predetermined threshold secondary current to prevent degradation of the device 9 in the event of failure.

[0055] The secondary threshold current is for example equal to 400A.

[0056] The control means 8 control the disconnectors 17 and the secondary static device 20 to cut the connection between the first 12, 13 end and said disconnector 17 when the current 12 is lower than the threshold secondary current.

[0057] The control means 8 comprise, for example, a processing unit controlling the disconnectors 17 and the secondary static device 20.

[0058] The control means 8 supervise each storage means 18 to identify a failure of a module 16 and isolate said branch 10, 11 comprising the module faulty of the other branch 11, 10 of the device 9 by opening the static device 20 of the faulty branch then by opening the disconnectors adjacent to the faulty module 16.

[0059] During a maintenance step of the device 9 on one of the storage branches 10, 11, the control means 8 open the secondary static device 20 of said branch 10, 11 then open the disconnectors 17 of said branch so that the voltage at the terminals of each module 16 is less than a voltage of 1500 volts.

[0060] Only low voltage authorization is necessary to work on the storage modules of the battery 5 when the disconnectors 17 are open.

[0061] When the disconnectors 17 are open, they can be connected to earth.

[0062] Alternatively, the secondary static device 20 connects the second ends 14, 15 of each branch 10, 11 to the disconnector 17 arranged between the second ends 14, 15 of each branch 10, 11 and the storage module 16 adjacent to the second ends 14, 15.

[0063] According to yet another variant, the device 9 does not comprise a secondary static device 20.

[0064] Alternatively, each branch comprises a different number of modules 16 other than three connected in series, each branch comprising at least two modules 16 connected in series.

[0065] The number of modules 16 connected in series is determined according to the value of the desired voltage at terminals 91, 92 of the device 9.

[0066] As each branch 10, 11 comprises three modules 16, the voltage at the terminals 91, 92 of the device 9 is equal to a maximum of 4500 volts.

[0067] The battery 5 delivering a maximum direct voltage of 4500 volts forms a medium voltage battery requiring only low voltage authorization to work on said battery 5.

[0068] Furthermore, only one conversion device 7 is required to power the bus 3 from the medium voltage battery 5.

[0069] According to another embodiment, the device 9 comprises at least one storage branch or more than two storage branches in parallel.

[0070] [Fig.3] illustrates a second example of embodiment of the battery 5.

[0071] The battery 5 comprises two devices 21, 22 identical to the device 9 connected in series.

[0072] The two free ends of the storage branches of the devices 21, 22 are each connected to a different connection terminal 51, 52 of the battery 5.

[0073] Connecting storage devices in series makes it possible to obtain a battery 5 with a higher voltage in order to store even more electrical energy, for example a maximum voltage of 9000 volts.

[0074] Of course, more than two storage devices can be connected in series.

[0075] According to another embodiment, the storage devices placed in series can each deliver a different voltage, the voltage at the terminals 51, 52 of the battery 5 being equal to the sum of the voltages delivered by the storage devices placed in series.

[0076] [Fig.4] illustrates an example of implementation of the storage system 4.

[0077] It is assumed that the disconnectors 17 are closed so that the battery 5 supplies the conversion device 7 via the primary static cut-off device 6.

[0078] During a lockout step 30, the control means 8 open the disconnectors 17 so that the voltage at the terminals of each module 16 is less than 1500 volts, allowing possible intervention on the modules 16, for example to replace a faulty module 16 or to carry out maintenance operations on one of the modules 16.

[0079] If the branches 10, 11 of the battery 5 each comprise a secondary static device 20, the control means 8 open the secondary static devices 20 then when the secondary static devices 20 are open, the control means 8 open the disconnectors 17.

[0080] When the intervention on the modules 16 is finished, during a step 31, the control means 8 close the disconnectors 17 so that the conversion device 7 transfers the electrical energy contained in the battery 5 to the bus 3.

[0081] If the branches 10, 11 of the battery 5 each comprise a secondary static device 20, the control means 8 close the disconnectors 17 then, when the disconnectors 17 are closed, the control means 8 close the secondary static devices 20.

[0082] If the current II is greater than the primary threshold current (step 32), the primary static cut-off device 6 cuts the connection between each storage device 9 of the battery 5 and the electrical energy conversion device 7 (step 33).

[0083] If the current 12 of one of the branches 10, 11 is greater than the secondary threshold current (step 34), the secondary static device 20 for cutting off said branch cuts the connection between said branch of the storage device 9 and the electrical energy conversion device 7 (step 33).

[0084] Since the electrical energy conversion device 7 is reversible, according to another operating mode of the electrical energy conversion device 7, the modules 16 of the battery 5 can be charged from an electrical energy source connected to the electrical energy conversion device 7.

[0085] The electrical energy source may for example comprise a wind turbine so that the electrical energy produced by the wind turbine is stored in the battery 5 for a further use.

Claims

Claims

1. A reversible electrical energy storage device (9) comprising at least one storage branch (10) comprising at least two energy storage modules (16), the ends (12, 14) of the storage branch being intended to be connected to a reversible electrical energy conversion device (7), the device further comprising disconnectors (17) connecting each end of the branch to an energy storage module and connecting the energy storage modules together in series, characterized in that each energy storage module (16) comprises an electrical energy storage means (18) and monitoring means (19) configured to measure electrical and thermal characteristics of each energy storage means and transmit the measured values ​​to control means (8).

2. Device according to claim 1, comprising at least one second storage branch (11) connected in parallel with said storage branch (10).

3. Device according to one of claims 1 or 2, in which a secondary static cut-off device (20) connects one of the ends (12, 13) of each branch (10, 11) to the disconnector (17) arranged between said end of said branch and said energy storage module adjacent to said end, the secondary static cut-off device being configured to cut the connection between said end and said disconnector when a current flowing in said secondary static cut-off device is greater than a predetermined threshold secondary current or upon receipt of a command issued by control means (8).

4. Battery (5) for storing electrical energy comprising at least two connection terminals (51, 52) and a reversible energy storage device (9) according to any one of claims 1 to 3, each end (12, 14) of the storage branch being connected to a different connection terminal.

5. Battery (5) for storing electrical energy comprising at least two connection terminals (51, 52) and at least two reversible energy storage devices (22, 21) according to any one of claims 1 to 3, the energy storage devices being connected in series, the two free ends of the storage branches each being connected to a different connection terminal.

6. Electrical energy storage system (4) comprising an electrical energy storage battery (5) according to one of claims 4 and 5, control means (8) configured to control the disconnectors (17) and a reversible electrical energy conversion device (7) connected to the terminals of the battery, the control means (8) being further configured to control, where appropriate, the secondary static cut-off device (20).

7. An electrical energy storage system (4) according to claim 6, further comprising a primary static cut-off device (6) connecting the reversible electrical energy conversion device (7) to the electrical energy storage battery (5), the primary static cut-off device being configured to cut the connection between the battery and the reversible electrical energy conversion device when a current flowing in said primary static cut-off device is greater than a predetermined primary threshold current.

8. Vessel (1) comprising an electrical energy storage system (4) according to one of claims 6 or 7.

9. Method for storing electrical energy, characterized in that the method comprises a locking step comprising the opening of disconnectors (17) of at least one storage branch (10, 11) of at least one reversible electrical energy storage device (9), said branch comprising at least two energy storage modules (16) and in which the disconnectors connect each end of the branch to an energy storage module and connect the energy storage modules together in series, characterized in that each energy storage module (16) comprises an electrical energy storage means (18) and monitoring means (19) configured to measure electrical and thermal characteristics of each energy storage means and transmit the measured values ​​to control means (8).

10. A method of storing electrical energy according to claim 9, comprising opening a primary static cut-off device (6) connecting a reversible electrical energy conversion device (7) to the electrical energy storage device (9) to cut the connection between the electrical energy storage device and the electrical energy conversion device when a current flowing in said primary static cut-off device is greater than a current predetermined threshold primary.

11. Method for storing electrical energy according to one of claims 9 or 10, comprising opening a secondary static cut-off device (20) connecting one end of the branch (10, 11) to the disconnector (17) arranged between said end of said branch and said energy storage module (16) to cut the connection between said end and said disconnector when a current flowing in said secondary static cut-off device is greater than a predetermined threshold secondary current.

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