SE545850C2

SE545850C2 - Capacitive deionization device comprising individually controllable cdi cell electrodes

Info

Publication number: SE545850C2
Application number: SE2151484A
Authority: SE
Inventors: Carrillo Esteban Toledo; Kunjali Karthik Laxman
Original assignee: Stockholm Water Tech Ab
Priority date: 2021-12-06
Filing date: 2021-12-06
Publication date: 2024-02-20
Also published as: WO2023104383A1; SE2151484A1

Abstract

The present disclosure relates to a capacitive deionization (CDI) device.In an aspect, a CDI device (40) is provided comprising at least one inlet (47) where aqueous media enters the CDI device (40), a plurality of CDI cells (41a, 41b, 41c) configured to subject the aqueous media to capacitive deionization, each CDI cell being arranged with a first electrode (43a, 43b, 43c) and a second electrode (44a, 44b, 44c) arranged to be energized with opposite charges via a respective conductor (45a, 45b, 45c, 46a, 46b, 46c) in order to subject the aqueous media flowing through the CDI cell to capacitive deionization, and at least one outlet (48) where the aqueous media having been subjected to capacitive deionization by the CDI cells (41a, 41b, 41c) exits the CDI device (40). The CDI device (40) further comprises a processing unit (42) to which the conductors (45a, 45b, 45c, 46a, 46b, 46c) are connected, the processing unit (42) being configured to individually control each of the electrodes for providing a required voltage (V+, V-) to energize the first electrode (43a, 43b, 43c) and the second electrode (44a, 44b, 44c) of each CDI cell (41a, 41b, 41c) with a desired charge and for controlling interconnection of the electrodes between the CDI cells (41a, 41b, 41c) to selectably configure the CDI cells (41a, 41b, 41c) in parallel or series configuration.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a capacitive deionization (CDI) device.

BACKGROUND

[0002] The need for clean and potable water is continuously increasing due to factors such as environmental issues and population growth. As a consequence, also the need for desalination or deionization of water, such as seawater or brackish water, is increasing. There are several techniques for deionization of water, including for example distillation, reverse osmosis and electrodialysis. Another example of a technique for deionization of water is capacitive deionization (CDI).

[0003] CDI is generally used for electrosorption of charged contaminants like salts, metal ions, and charged organics from brackish water or other water sources which are not immediately suitable for human consumption. Compared to the formerly mentioned techniques, CDI has the advantage of being a relatively energy- efficient technology, especially for water having a fairly moderate charged contaminant concentration such as brackish water.

[0004] In the CDI technology, electrically conducting electrodes of activated carbon may be utilised for electrosorption of all types of charged contaminants. A selected number of CDI cells can be arranged in a CDI device depending on required electrosorption capacity of the CDI device; the higher the capacity, the greater the number of CDI cells. A typical CDI cell comprises of two oppositely placed electrodes separated by a non-conductive spacer through which water can ﬂow. The electrodes are polarized positively and negatively using a DC power source. Charged contaminants of counter-charge are electrically attracted to the respective electrodes and temporarily held by the electrodes. Thereby, the charged contaminants are removed from water present between the electrodes and the water being output from the CDI cell has thus been deionized and purified.

[0005] The deionization performance and net power consumption of a CDI device is a function of the connection configuration of the CDI cells inside a CDI device. For example, series connected cells require higher CDI voltage ratings, while parallel connected cells require lower DC voltage but higher DC current ratings. In addition, the net capacitance of the CDI device can also be affected based on the configuration of CDI cells within a CDI device.

[0006] A problem with a prior art CDI device is that the CDI cells included therein either are configured in a parallel or a series configuration, or a combination thereof where e.g. one set of cells is configured in series and connected in parallel with another set of series-coupled cells, which makes for a predefined an inﬂexible configuration and operation.

SUMMARY

[0007] One objective is to solve, or at least mitigate, this problem in the art and thus to provide an improved and more ﬂexible CDI device.

[0008] This is attained in an aspect by a CDI device comprising at least one inlet where aqueous media enters the CDI device, a plurality of CDI cells configured to subject the aqueous media to capacitive deionization, each CDI cell being arranged with a first electrode and a second electrode arranged to be energized with opposite charges via a respective conductor in order to subject the aqueous media ﬂowing through the CDI cell to capacitive deionization, and at least one outlet where the aqueous media having been subjected to capacitive deionization by the CDI cells exits the CDI device. The CDI device further comprises a processing unit to which the conductors are connected, the processing unit being configured to individually control each of the electrodes for providing a required voltage to energize the first electrode and the second electrode of each CDI cell with a desired charge and for controlling interconnection of the electrodes between the CDI cells to selectably configure the CDI cells in parallel or series configuration.

[0009] Advantageously, with this structure, the processing unit can selectably interconnect the electrodes of the CDI cells to attain any desired configuration. Further, the processing unit provides (e.g. from an external power supply) each electrode with the required voltage V+ or V- provided by conductors of the power supply. [0010] In an embodiment, the CDI device further comprises a wireless communication receiver configured to wirelessly receive user instructions to the processing unit on how to configure the CDI cells.[0011] In an embodiment, the CDI device further comprises a control interface via which the processing unit is configured to receive user instructions on how to configure the CDI cells.

[0012] In an embodiment, the control interface comprises a touch screen or a keypad and display via which a user may enter configuration instructions to the processing unit for configuring the CDI cells.

[0013] In an embodiment, the CDI device further comprises one or more sensors configured to measure current and/ or voltage of each conductor.

[0014] In an embodiment, the processing unit is configured to determine from the measured currents and/ or voltages if one or more CDI cells are faulty.

[0015] In an embodiment, the CDI device further comprises an interface configured to be connected to an external power source for powering the CDI device.

[0016] In an embodiment, the CDI device further comprises an internal power source configured to at least partly power the CDI device.

[0017] In an embodiment, the internal power source (59) being configured to be chargeable by the external power source via the interface (58).

[0018] In an embodiment, said one or more sensors configured to measure current and/ or voltage of each conductor is further configured to measure current and/ or voltage being supplied to the CDI device from the external power source or the internal power source, and the processing unit is configured to reconfigure the CDI cells to a configuration matching a current and/ or voltage delivery capacity of the external power source or the internal power source.

[0019] In an embodiment, the processing unit is configured to reconfigure the CDI cells to a configuration requiring less current and/ or voltage if the external power source or the internal power source does not have capacity to deliver a currently required current and/ or voltage to one or more of the CDI cells.

[0020] In an embodiment, the processing unit is configured to reconfigure the CDI cells to a configuration requiring more current and/ or voltage if the external power source or the internal power source have capacity to deliver a higher current and/ or voltage than the currently required current and/ or voltage to one or more of the CDI cells.[0021] In an embodiment, the processing unit is configured to supply power discharged by the CDI cells via the conductors during regeneration of the CDI cells to an energy storage.

[0022] In an embodiment, the energy storage is the internal power source or the external power source connected to the CDI device via the interface.

[0023] In an embodiment, the processing unit is configured to select a CDI cell configuration delivering an expected power and/ or voltage and/ or current via the conductors during regeneration.

[0024] In an embodiment, the processing unit is a microprocessor, a field- programmable gate array (FPGA) a complex programmable logic device (CPLD) or an application-specific integrated circuit (ASIC).

[0025] In an embodiment, the CDI device further comprises a front end plate being arranged with the inlet and the outlet, a main body arranged to accommodate the CDI cells, a back cover plate comprising through-holes via which the conductors pass between the CDI cell electrodes and the processing unit, and a back end plate being arranged with a cavity configured to accommodate the processing unit.

[0026] In an embodiment, a back end face of the back end plate is arranged with the interface configured to be connected to an external power source for powering the CDI device.

[0027] In an embodiment, each CDI cell is being arranged with a third electrode arranged to be energized via a respective conductor connected to the processing unit and which third electrode is configured to enable control and distribution of energy equally between the first electrode and the second electrode.

[0028] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Aspects and embodiments are now described, by way of example, with reference to the accompanying drawings, in which: [0030] Figure 1 schematically illustrates a prior art CDI device;

[0031] Figure 2 shows in a left-hand illustration a prior art 3-electrode CDI device while a right-hand illustration shows a cross-section of the CDI device taken along line B-B;

[0032] Figure 3 illustrates a prior art CDI device where CDI cells are coupled in parallel;

[0033] Figure 4 illustrates a prior art CDI device where CDI cells are coupled in series; [0034] Figure 5 illustrates a CDI device according to an embodiment;

[0035] Figure 6 illustrates a CDI device of Figure 5 where the CDI cells are coupled in a specific configuration according to an embodiment;

[0036] Figure 7 illustrates a front perspective exploded view of a CDI device according to an embodiment; and

[0037] Figure 8 illustrates a back perspective exploded view of the CDI device of Figure 7 according to an embodiment.

DETAILED DESCRIPTION

[0038] The aspects of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown.

[0039] These aspects may, however, be embodied in many different forms and should not be construed as limiting; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and to fully convey the scope of all aspects of invention to those skilled in the art. Like numbers refer to like elements throughout the description.

[0040] Figure 1 schematically illustrates a prior art CDI device 10 comprising a first electrode 2 and a second electrode 3. These electrodes are sometimes referred to as "primary electrodes" or "master electrodes". This is referred to as a ﬂat cell architecture, and while the architecture of prior art CDI devices may take on many different forms that does not necessarily have the appearance of that of Figure 1, Figure 1 is included for describing basic operational principle of a CDI device.

[0041] In Figure 1, the first and second electrodes are planar electrodes arranged in opposite, preferably in parallel to, each other. Aqueous media from which charged contaminants are to be removed is intended to ﬂow through the entire volume of the CDI device 10 including the first electrode 2 and the second electrode 3, as the electrode materials are permeable to aqueous media being for instance brackish water.

[0042] The first and second electrodes 2, 3 are usually separated by a first electrically nonconductive spacer 4. The device 10 further optionally comprises more than one non-conductive spacer, as illustrated in Figure 1 by a second electrically nonconductive spacer 4'. The purpose of the nonconductive spacer(s) is primarily to avoid the risk of electrical short-circuit between the first electrode 2 and the second electrode 3 during operation of the device

[0043] Aqueous media, such as water to be purified, is preferably passed through the nonconductive spacer(s). Usually, the electrodes 2, 3 are in direct contact with the spacer(s).

[0044] The CDI device 10 further comprises a first current collector 5 connected to the first electrode 2, and a second current collector 6 connected to the second electrode 3. In a conventional CDI device, the electrode selected as cathode is generally connected to the negative terminal of a DC supply, which is typically connected to electrical ground and the electrode selected as anode is polarized with reference to the cathode and connected to the positive terminal of the DC supply. The electrodes 2, 3 are connected via the respective current collectors 5, 6 to a DC power source (not shown) in order to enable polarization of the electrodes.

[0046] During operation of the CDI device 10, negatively charged contaminants are attracted to the positive electrode and held non-permanently in the positive electrode, while positively charged contaminants are attracted to the negative electrode and held non-permanently therein. Thereby, the charged contaminants are removed from the aqueous media present between the electrodes.[0047] The Applicant has further disclosed in European patent no. EP 3 642 165 optional use of a third electrode 8 arranged between the two primary electrodes 2, 3. As is understood, ion removal and capacity is proportional to the distribution and strength of the electric field generated at each of the primary electrodes 2,

[0048] The third electrode 8 is configured to be electrically grounded and the two primary electrodes 2, 3 are configured to be polarized with opposite charges with respect to the grounded third electrode 8. This ensures that the potential is divided substantially equally between the positive and negative electrodes, thus enabling symmetric removal capacities of negatively and positively charged contaminants which prevents unwanted changes in water pH and chemistry.

[0049] Figure 2 shows in a left-hand illustration a 3-electrode CDI deviceoperating according to the above description for Figure

[0050] The CDI device 20 of Figure 2 comprises an outer housing 21 adapted to confine the aqueous media inside the CDI cell during the deionization process. The outer housing 21 may have a cylindrical configuration such that it comprises a first end surface 21a, an envelope surface 21b, and a second end surface (not shown) opposing the first end surface 21a.

[0051] The housing 21 comprises an inlet 29 through which the aqueous media is introduced into the CDI device 20, and an outlet 30 through with the aqueous media exits the CDI device 20 after the deionization. The inlet and outlet may be concentric with the central axis of the CDI device 20, however other configurations are also possible. It may alternatively be envisaged that the inlet 29 and the outlet 30 are arranged at the same end of the CDI device

[0052] The CDI device 20 further comprises a first electrode 22 and a second electrode 23 (i.e. the primary electrodes) energized via conductors 25 and

[0053] The right-hand illustration shows a cross-section of the CDI device 20 taken along the line B-B where water to be cleaned ﬂows through the cylindrically shaped CDI device 20 entering at inlet 29 and exiting at outlet

[0054] The first electrode 22 and the second electrode 23 are wound about each other inside the cylindrical CDI device 20 and thus forms a circular cross-section. Further, the CDI device 20 comprises at least one electrically non-conductive spacer arranged in the space 24 between each turn of the electrodes around the central axisin order to avoid electrical short-circuiting between the first electrode 22 and the second electrode

[0055] During operation of the CDI device 20, negatively charged contaminants are attracted to the positive electrode and held-non-permanently in the positive electrode (i.e. to the first electrode 22 or the second electrode 23 depending on the energization). Simultaneously, positively charged contaminants are attracted to the negative electrode and held-non-permanently therein. Thereby, the contaminants are removed from the water ﬂowing through the CDI device 20 hence cleaning the water. As discussed, the CDI device 20 may further optionally comprise the third electrode 27 grounded via conductor 28 for serving the purpose of enabling control and distribution of the energy substantially equally between the first electrode 22 and the second electrode

[0056] As shown in Figures 3 and 4, the prior art CDI 20 (comprising three CDI cells in this particular example, but may in practice comprise tens of cells) is either configured in a parallel or a series configuration, or a combination where e.g. one set of cells is configured in series and connected in parallel with another set of series- coupled cells).

[0057] In the parallel configuration, each CDI cell operates independently of the others and hence a failure of one cell does not affect the other cells. However, all CDI cells are powered simultaneously and since each cell has independent current needs, the power supply should be able to deliver high current at low voltage.

[0058] In the series configuration, demands on the power supply is lower but the system is more vulnerable to failure. If one cell in the link fails, all cells fail and the system cannot operate. Typically, voltage requirements are higher and current needs are lower.

[0059] The electrodes 23a-c and 24a-c are energized via a positive-polarity conductor 25 and a negative-polarity conductor 26, respectively, which conductors in their turn are connected to an external power supply (not shown).

[0060] In other words, a problem in the art is that the selected configuration series / parallel / combination) is hardwired and reconfiguration is not possible unless the electrode conductors 25, 26 are physically re-routed.[0061] Figure 5 functionally illustrates a CDI device 40 according to an embodiment which overcomes this problem. As is understood, the CDI device 40 comprises an inlet 39 for aqueous media such as water to be cleaned, and an outlet where cleaned water exits the CDI device 40. In this particular exemplifying embodiment, the CDI device 40 comprises three CDI cells 41a, 41b, 41c for desalting the incoming water. [0062]

[0063] In the CDI device 40 of the embodiment illustrated in Figure 5, each first electrode 43a, 43b, 43c and each second electrode 44a, 44b, 44c is connected via an individual conductor 45a, 45b, 45c, 46a, 46b and 46c, respectively, to a central processing unit 42 (CPU) in the form of for example a microprocessor.

[0064] Further illustrated are the optional third electrodes 61a, 61b, 61c each connected to the CPU 42 via an individual conductor 62a, 62b and 62c, respectively.

[0065] Advantageously, with this structure, the CPU 42 can selectably interconnect the electrodes of the CDI cells 41a, 41b, 41c to attain any desired configuration. Further, the processing unit 42 provides (e.g. from an external power supply) each electrode with the required voltage V+ or V- provided by conductors 45, 46 of the power supply.

[0066] The optional third electrodes 61a, 61b, 61c will not be discussed in further detail in the following as these electrodes in this particular example all are connected to ground. Nevertheless, the CPU 42 may individually address the third electrodes if required via the corresponding conductors 62a, 62b, 62c.

[0067] Thus, the CPU 42 serves as switching logic for interconnecting the electrodes as desired and providing the required voltage. In case of using a CPU 42, it may be necessary to have the CPU 42 executing different pieces of software for different series / parallel configurations being selected. As is understood, the software may be stored in an internal memory of the CPU 42 or an external memory located adjacent to the CPU

[0068] Figure 6 illustrates a particular configuration being selected by the CPU 42 as required by a user or operator of the CDI device 40. As mentioned, the optional third electrodes are shown in Figure 6, but are assumed to be connected via the CPU 42 to ground. 1O

[0069] Assuming for instance that the CDI device 40 is configured with all three cells connected in parallel in order to be failure-proof, but that it has been noted that the power grid (i.e. the external power source) from time to time - such as for instance between 17:00 and 19:00 weekdays - cannot deliver the amount current required for implanting the fully parallel configuration.

[0070] An operator of the CDI device 40 may hence select a less power-consuming configuration. For instance, the operator may determine that first cell 41a and second cell 41b should be coupled in series to consume less power, while third cell 41c is connected in parallel to provide redundancy.

[0071] It may be envisaged that the CDI device 40 is arranged with a control interface, such as a touch screen or a keypad and display, where the user freely may select configuration for the CPU 42 to execute.

[0072] It may further be envisaged that the user downloads an app to her phone or tablet via which the user selects a desired configuration and sends a configuration instruction accordingly to the CDI device 40 wirelessly for the CPU 42 to execute.

[0073] Now, the CPU 18 performs the following interconnections to attain the above-described configuration where the first cell 41a is coupled in series with the second cell 41b while the third cell 41c is connected in parallel with both the first cell 41a and the second cell 41b: - 2ttd electrode 44a of 1st cell is connected via conductor 46a to negative polarity V-; - 1st electrode 43a of 1st cell 41a is connected via 2ttd conductor 45a to conductor 46b and further to 2ttd electrode 44b of 2ttd cell 41b; - 1st electrode 43b of 2ttd cell 41b is connected via conductor 45b to positive polarity V+; - 1st electrode 43c of gtd cell 41c is connected via conductor 45c to positive polarity V+; and - 2ttd electrode 44c of gtd cell 41c is connected via conductor 46c to negative polarity V-.[0074] As advantageously can be concluded, the CPU 42 may selectively interconnect any one electrode to another electrode and further supply any one electrode with a desired polarity.

[0075] The CPU 42 incorporates a voltage processing unit (or has an external voltage processing unit connected to it) since if the cell configuration is changed, the CPU 42 will generally also dynamically have to change the DC voltage that is applied to the electrodes via the corresponding conductors.

[0076] Figure 7 illustrates a front perspective exploded view of a CDI device 40 according to an embodiment. This particular CDI device 40 is arranged with both inlet 47 and outlet 48 through the same pipe at a front end covered by a front end plate 50. Thus, the pipe will be switched from serving as an inlet 47 to serving as an outlet 48 and vice versa.

[0077] The CDI device 40 further comprises a cylindrically shaped main bodyaccommodating a plurality of CDI cells.

[0078] The main body 51 is closed at a back end by a back cover plate 52 to which a back end plate 53 is attached by means of fasteners such as screws 54. The back end plate 53 is arranged with a cavity in which the CPU 42 is accommodated, to which CPU the individually addressable CDI cell electrode conductors 45a, 46a are connected via through-holes

[0079] In this example, an I/ U sensor 49 is further arranged in the cavity of the back end plate 53 for measuring voltage and/ or current of the conductors 45a, 46a, 61a and possibly also the amount of power being supplied to the individual CDI cells and the whole CDI device 40, as will be described.

[0080] The CPU 42 may further be connected to a wireless communication receiver and/ or transmitter, such as a transceiver 56, for communicating with a remotely located device such as a smart phone 60. As previously mentioned, the CDI device 40 may in an embodiment be capable of receiving configuration instructions from the user via the smart phone 60 and the transceiver 56 which are forwarded to the CPU 42 for configuring the cells as desired.

[0081] The CDI 40 may further comprise a control interface 57, such as a touch screen or a keypad and display, via which a user may enter configuration instructions to the CPU 42 for configuring the cells as desired.[0082] Figure 8 illustrates a back perspective exploded view of the CDI deviceof Figure 7 according to an embodiment.

[0083] As illustrated, the main body 51 of the CDI device 40 accommodates a multitude of CDI cells 41. In this exemplifying embodiment, the CDI device 40 comprises 18 cells, but any appropriate number may be envisaged depending on application. Further shown is an interface 58 to an external power supply arranged at a back face of the back end plate

[0084] In an alternative embodiment, the CDI device 40 comprises an internal power source 59, for instance located in the cavity of the back end plate 53 adjacent to the CPU

[0085] In a further embodiment, it is envisaged that the internal power sourcemay be charged by an external power source via the interface

[0086] In an embodiment, the I/ U sensor 49 is arranged to measure current and/ or voltage of the conductors 45a-c, 46a-c and 62a-c being individually connected to each electrode 43a-c, 44a-c and 61a-c.

[0087] Advantageously, by measuring the voltage and/ or current of each CDI cell 41a-41c, the CPU 42 may detect a potentially faulty cell. In response to detecting one or more faulty cells, the CDI device 41 may be reconfigured by the processing unit. The CPU 42 may for instance conclude that there is a short circuit in a cell if a current on a conductor is too high or if the voltage between the electrodes of a cell is too low.

[0088] For instance, assuming that the three cells 41a-c are connected in series and the second (middle) cell 41b becomes faulty, the CPU 42 may reconfigure the electrodes 43a, 44a and 43c, 44c of the remaining two cells 41a and 41c such that the first and the third cells 41a, 41c are connected in series (and the second cell 41b is disconnected). Even though the deionization capacity of the CDI device 40 may be decreased, it is still possible for the device to continue operation.

[0089] Further in an embodiment, the I/ U sensor 49 is also configured to measure current and/ or voltage being supplied to the CDI device 40 from the external power source (or the internal power source 59). Advantageously, the CPU 42 may then itself select a suitable CDI cell configuration by taking into account the supply capacity of the internal / external power source.[0090] For instance, with reference to the example described with reference to Figure 6; the CPU 42 may determine from the measured current and/ or voltages of the I/ U sensor 49 the current and/ or voltage required by each CDI cell 41a, 41b, 41c in a particular configuration, such as all three CDI cells being coupled in parallel.

[0091] The CPU 42 may then determine, using the I/ U sensor 49, current and/ or voltage delivery capacity of the internal / external power source.

[0092] In this example, the CPU 42 determines that the internal / external power source cannot meet the requirements, for instance that the power source cannot deliver the required current, and therefore selects an alternative configuration which the power source has the capacity to serve, namely the first cell 41a and the second cell 41b coupled in series while the third cell 41c is coupled in parallel.

[0093] Conversely, if the internal/ external power source can deliver more current and/ or voltage than what is currently required by the CDI cells 41a, 41b, 41c, a more demanding configuration may be selected, such as more cells being coupled in parallel.

[0094] As mentioned, in case the CPU 42 is a microprocessor, the CPU 42 will execute different pieces of software for different series/parallel configurations being selected, which advantageously may be performed on the ﬂy.

[0095] In case the CPU 42 is a field-programmable gate array (FPGA) or a complex programmable logic device (CPLD), the CPU 42 will have to be reprogrammed if a different configuration is selected which may require that the operation of the CDI device 40 is temporarily paused.

[0096] In case an application-specific integrated circuit (ASIC) is utilized, the ASIC must be changed to another ASIC providing the new configuration since ASICs are hardwired. As is understood, any appropriate custom made hardware device with these capabilities may be utilized.

[0097] With reference again to Figure 5, the positive and negative contaminants in water - i.e. the water waste - temporarily held by the electrodes of the CDI cells must occasionally be released and ﬂushed from the CDI device in order to prevent excessive accumulation of the contaminants at the electrodes, since such accumulation will decrease the contaminants removal capacity of the CDI device This process is referred to as regeneration.[0098] Thus, assuming that for the first cell 41a, the first electrode 43a is connected to the positive polarity V+ thereby attracting and temporarily storing the negatively charged contaminants, while the second electrode 44a is connected to the negative polarity V- thereby attracting and temporarily storing the positively charged contaminants.

[0099] During regeneration of the first CDI cell 41a, the positive polarity V+ will be removed for the first electrode 43a while the negative polarity V- will be removed for the second electrode 44a (and they may both be connected to the third electrode 61a which is connected to circuit ground; in other words the three electrodes will be short-circuited with each other). As a result, the positive and negative contaminants will be released from the respective electrode.

[00100] Now, a CDI cell of a CDI device works like a capacitor which stores energy when it is cleaning water (i.e. temporarily holding positive and negative contaminants) and discharges energy when it is releasing the waste.

[00101] The energy of e.g. the first cell 41a will thus be discharged via the first electrode 43a and the second electrode 44 and the respective conductors 45a and 46a, respectively.

[00102] Advantageously, the CPU 42 is in an embodiment configured to transport the energy discharged by a CDI cell - in this example the energy being discharged from the first CDI cell 41a via the conductors 45a and 46a, - to an energy storage such as the internal power source 59 being for instance a rechargeable battery.

[00103] In a further embodiment, it is envisaged that the discharged energy is output via the interface 58 to the external power supply, in which case it ultimately may be fed back to the power grid.

[00104] In case of an internal rechargeable battery 59, such batteries typically have an operating voltage of 12 V or 24 V, while a CDI cell of a CDI device typically have a peak voltage ranging from 1.2 VDC to 3 VDC.

[00105] The CPU 42 may in such case connect six CDI cells (in case of a 12-V battery) or twelve CDI cells (in case of a 24-V battery) in series to provide the required charging voltage or 12 V or 24 V during regeneration of the CDI device

[00106] Hence, the CPU 42 is configured to select a CDI cell configuration delivering an expected power and/ or voltage and/ or current via the conductors 45a, 45b, 45c, 46a, 46b, 46c during regeneration.

[00107] The aspects of the present disclosure have mainly been described above with reference to a few embodiments and examples thereof. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims.

[00108] Thus, while various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims

1. A capacitive deionization, CDI, device (40) comprising: at least one inlet (47) where aqueous media enters the CDI device (40); a plurality of CDI cells (41a, 41b, 41c) configured to subject the aqueous media to capacitive deionization, each CDI cell being arranged with a first electrode (43a, 43b, 43c) and a second electrode (44a, 44b, 44c) arranged to be energized with opposite charges via a respective conductor (45a, 45b, 45c, 46a, 46b, 46c) in order to subject the aqueous media ﬂowing through the CDI cell to capacitive deionization; and at least one outlet (48) where the aqueous media having been subjected to capacitive deionization by the CDI cells (41a, 41b, 41c) exits the CDI device (40); the CDI device (40) further comprising: a processing unit (42) to which the conductors (45a, 45b, 45c, 46a, 46b, 46c) are connected, the processing unit (42) being configured to individually control each of the electrodes for providing a required voltage (V +, V-) to energize the first electrode (43a, 43b, 43c) and the second electrode (44a, 44b, 44c) of each CDI cell (41a, 41b, 41c) with a desired charge and for controlling interconnection of the electrodes between the CDI cells (41a, 41b, 41c) to selectably configure the CDI cells (41a, 41b, 41c) in parallel or series configuration.

2. The CDI device (40) of claim 1, further comprising: a wireless communication receiver (56) configured to wirelessly receive user instructions to the processing unit (41) on how to configure the CDI cells (41a, 41b, 41c).

3. The CDI device (40) of claims 1 or 2, further comprising: a control interface (57) via which the processing unit (42) is configured to receive user instructions on how to configure the CDI cells (41a, 41b, 41c).

4. The CDI device (40) of claim 3, a control interface (57) comprising: a touch screen or a keypad and display via which a user may enter configuration instructions to the processing unit (42) for configuring the CDI cells (41a, 41b, 41c).

5. The CDI device (40) of any one of the preceding claims, further comprising: one or more sensors (49) configured to measure current and/ or voltage of each conductor (45a, 45b, 45c, 46a, 46b, 46c).

6. The CDI device (40) of claim 5, the processing unit (42) being configured to determine from the measured currents and/ or voltages if one or more CDI cells (41a, 41, 41c) are faulty.

7. The CDI device (40) of any one of the preceding claims, further comprising: an interface (58) configured to be connected to an external power source for powering the CDI device (40).

8. The CDI device (40) of any one of the preceding claims, further comprising: an internal power source (59) configured to at least partly power the CDI device (40)-

9. The CDI device (40) of claims 7 and 8, the internal power source (59) being configured to be chargeable by the external power source via the interface (58).

10. The CDI device (40) of any one of claims 7-9, wherein: said one or more sensors (49) configured to measure current and/ or voltage of each conductor (45a, 45b, 45c, 46a, 46b, 46c) further is configured to measure current and/ or voltage being supplied to the CDI device (40) from the external power source or the internal power source (59); and the processing unit (42) is configured to reconfigure the CDI cells (41a, 41b, 41c) to a configuration matching a current and/ or voltage delivery capacity of the external power source or the internal power source (59).

11. The CDI device (40) of claim 1o, wherein: the processing unit (42) is configured to reconfigure the CDI cells (41a, 41b, 41c) to a configuration requiring less current and/ or voltage if the external power source or the internal power source (59) does not have capacity to deliver a currently required current and/ or voltage to one or more of the CDI cells (41a, 41b, 41c).

12. The CDI device (40) of claims 1o or 11, wherein: the processing unit (42) is configured to reconfigure the CDI cells (41a, 41b, 41c) to a configuration requiring more current and/ or voltage if the external power sourceor the internal power source (59) have capacity to deliver a higher current and/ or voltage than the currently required current and/ or voltage to one or more of the CDI cells (41a, 41b, 41c).

13. The CDI device (40) of any one of claims 7-12, wherein: the processing unit (42) is configured to supply power discharged by the CDI cells (41a, 41b, 41c) via the conductors (45a, 45b, 45c, 46a, 46b, 46c) during regeneration of the CDI cells (41a, 41b, 41c) to an energy storage.

14. The CDI device (40) of claim 13, the energy storage being the internal power source (59) or the external power source connected to the CDI device (40) via the interface (58).

15. The CDI device (40) of any one of claims 13 or 14, wherein the processing unit (42) is configured to select a CDI cell configuration delivering an expected power and/ or voltage and/ or current via the conductors (45a, 45b, 45c, 46a, 46b, 46c) during regeneration.

16. The CDI device (40) of any one of the preceding claims, the processing unit (42) being a microprocessor, a field-programmable gate array, FPGA, a complex programmable logic device, CPLD, or an application-specific integrated circuit, ASIC.

17. The CDI device (40) of any one of the preceding claims, further comprising: a front end plate (50) being arranged with the inlet (47) and the outlet (48); a main body (51) arranged to accommodate the CDI cells (41a, 41b, 41c): a back cover plate (52) comprising through-holes (55) via which the conductors (45a, 45b, 45c, 46a, 46b, 46c) pass between the CDI cell electrodes (43a, 43b, 43c, 44a, 44b, 44c) and the processing unit (42); and a back end plate (53) being arranged with a cavity configured to accommodate the processing unit (42).

18. The CDI device (40) of claims 7 and 14, wherein: a back end face of the back end plate (53) being arranged with the interface (58) configured to be connected to an external power source for powering the CDI device (40)-

19. The CDI device (40) of any one of the preceding claims, each CDI ce11 being arranged with a third e1ectrode (61a, 61b, 61c) arranged to be energized via a respective conductor (62a, 62b, 62c) connected to the processing unit (42) and which third e1ectrode is configured to enable control and distribution of energy equa11y between the first e1ectrode (43a, 43b, 43c) and the second e1ectrode (44a, 44b, 44c).