An electrochemical desalination system (10) includes a first and a second electrochemical device (12, 14) and a controller (18). The first and second electrochemical devices (12, 14) each comprises a electrochemical desalination module comprising at least one pair of electrodes (32, 33, 34, 35) and a compartment between each pair of electrodes (32, 33, 34, 35) for receiving an electrolyte solution. Each of the first and second electrochemical desalination devices comprises a plurality of successive operation cycles. Each cycle comprises a charging mode of operation for charging each pair of electrodes (32, 33, 34, 35) and for adsorbing ions in the electrolyte solution on the electrodes, and a discharging mode of operation for discharging the pair of electrodes (32, 33, 34, 35) and for desorbing ions from the pair of electrodes (32, 33, 34, 35). One of the first and second electrochemical desalination devices is in a discharging mode and the at least one pair of electrodes release electrical current, while the other of the first and second electrochemical desalination devices is in a charging mode of operation and receives the electrical current released from said one of the first and second electrochemical desalination device.

WE CLAIM :
1. An electrochemical desalination system comprising:
a first and a second electrochemical devices each comprising an electrochemical desalination module comprising at least one pair of electrodes and a compartment between each pair of electrodes for receiving an electrolyte solution, each of the first and second electrochemical desaUnation devices comprising a plurality of successive operation cycles, each cycle comprising a charging mode of operation for charging each pair of electrodes and for adsorbing ions in the electrolyte solution on the electrodes, and a disdiarging mode of operation for discharging the pair of electrodes and for desorbing ions iix)m the pair of electrodes; and
a controller configured to control the system that the first and second electrochemical desalination devices have interleaved charging and discharging modes of operation, wherein one of the first and second electrochemical desalination devices is in a discharging mode and the at least one pair of electrodes release electrical current, while the other of the first and second electrochemical desalination devices is in a charging mode of operation and receives the electrical current released from said one of the first and second electrochemical desalination device.
2. The system of claim 1, wherein the controller is configured to control the system such that each of the first and second electrochemical desalination devices has an equal cycle time.
3. The system of claim 1, wherein the controller is configured to control the system such that a charging time for the charging mode of operation equals a discharging time for the discharging mode of operation for each of the first and second electrochemical desalination devices.
4. The system of claim 1, wherein the controller is configured to control the system such that the charging mode of operation of each of the Hrst and second electrochemical desalination devices comprises a normal discharging mode of operation and a compulsory discharging mode of operation.

5. The system of claim 1, wherein the first and second electrochemical desalination devices comprise at least one bi-directional converter electrically connected between the electrochemical desalination module and a power supply.
6. The system of claim 5, wherein each of the bi-directional converters comprises a bi-directional DC/DC converter for transmitting a direct current to the electrochemical desalination module of one of the first and second electrochemical desalination devices during the charging mode of operation, and transmitting a direct current to the other of the first and second electrochemical desalination devices.
7. The system of claim 1, comprises at least two first electrochemical desalination devices connected in series and at least two second electrochemical desalination devices connected in series for respectively continuous removal of ions.

8. The system of claim 7, wherein the controller is configured to control one of the at least two electrochemical desalination devices to have interleaved diarging and discharging modes of operation with at least one of the at least two second electrochemical desalination device.
9. An electrochemical desalination method comprising:
operating a first electrochemical desalination device in a chargmg mode of operation comprising:
charging at least one pair of electrodes of the first electrochemical desalination device with opposite polarities;
passing an electrolyte solution through a compartment between each pair of electrodes of the first electrochemical desalination device;
adsorbing ions in the electrolyte solution on the at least one pair of electrodes; and
exiting a dilute solution out of the first electrochemical desalination device; and

operating the first electrochemical desalination device in a discharging mode of operation comprising:
releasing electric energy stored in the at least one pair of electrodes of the first electrochemical desalination device to a second electrochemical desalination device, and charging at least one pair of electrodes of the second electrochemical desalination device using the electric energy released by the at least one pair of electrodes of the first electrochemical desalination device; and
desorbing ions accumulated on the at least one pair of electrodes of the first electrochemical desalination device into the electrolyte solution in the compartment.
10. The method of claim 9, wherein charging the at least one pair of electrodes of a first electrochemical desalination device comprises receiving a direct current released during a discharging mode of operation of the at least one pair of electrodes of the second electrochemical desalination device.
11. The method of claim 10 further comprising obtaining charging/discharging current profiles for the first and second electrochemical desalination devices, and controlling a converter to output currents for charging/disdiarging the pairs of electrodes respectively according to the charging/discharging current profiles.

12. The method of claim 9, wherein the discharging mode of operation comprises a normal discharging mode of operation for a normal discharging time and releasing a direct ciurent driven by the electric energy stored in the at least one pair of electrodes in the first electrochemical desalination device during the normal discharging time.
13. The method of claim 12, wherein the normal discharging mode of operation comprises comparing if an instantaneous discharging energy released from the pair of electrodes of the first electrochemical desalination device meet an

instantaneous energy requirement for charging the pair of electrodes of the second electrochemical desalination device.
14. The method of claim 13, wherein comparing comprises comparing an
instantaneous discharging electric power of the flrst electrochemical desalination
device with an instantaneous charging electric power of the second electrochemical
desalination device.
15. The method of claim 12, wherein the discharging mode of operation further comprises a compulsory discharging mode of operation for a compulsory discharging time by transmitting a direct current to the at least one pair of electrodes of the first electrochemical desalination device with revised polarities.
16. The method of claim IS further comprising calculating and determining a normal discharging current, normal discharging time, compulsory discharging current and compulsory discharging time based on a previous operation cycle or the average of several previous operation cycles.
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17. The method of claim 16, wherein the calculating and determining of the
normal discharging time and compulsory disdiarging time is repeated at a certain time
interval.
18. The method of claim 17, wherein the normal charging time and
compulsory discharging time are determined such that a difference of an energy
output from the Hrst electrochemical desalination device and an energy input to the
first electrochemical desalination device is maximized.
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MANISHA SINGFrnklT?
Agentforthe Applic : ~101
LEXORBIS
Intellectual P^, 709/710, T< , . . 15-17,Toi^;. NewDel2ii-liL-ov;i
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