Power supply for electro-synthetic or electro-energy cells

Abstract

Disclosed is a system and method for supplying electrical power to an electro-synthetic cell. A traction inverter is electrically connected to the electro-synthetic cell. The traction inverter comprises a control system. The control system is configured to operate the traction inverter in reverse, such that an alternating current (AC) input to the traction inverter is converted into a direct current (DC) output from the traction inverter to power the electro-synthetic cell.

Description

POWER SUPPLY FOR ELECTRO-SYNTHETIC OR ELECTRO-ENERGY CELLSTECHNICAL FIELD

[0001] The present invention broadly relates to power supply; and, more particularly, to power supply for electrochemical cells, for example, electro-synthetic or electro-energy cells. Example embodiments relate to systems and / or methods for power supply to electrosynthetic or electro-energy cells, such as industrial cell stacks wherein the architecture of single cells is such that numerous cells can be stacked together to effectively constitute a single electro-synthetic or electro-energy device or apparatus.BACKGROUND

[0002] An electro-energy cell is an electrochemical cell that generates electrical power over sustained periods of time, for use outside of the cell. Electro -energy cells are distinguished from other galvanic cells in that they require a constant external supply of reactants. The products of the electrochemical reaction must be also constantly removed from such cells. Unlike a battery, an electro-energy cell does not store chemical or electrical energy within the electro-energy cell.

[0003] Examples of electro-energy cells include but are not limited to hydrogen-oxygen Polymer Electrolyte Membrane (PEM) fuel cells, hydrogen-oxygen alkaline fuel cells, ammonia fuel cells, and the like.

[0004] An electro-synthetic cell may be similarly considered to be an electrochemical cell that manufactures one or more chemical materials over sustained periods of time, for use outside of the cell. The chemical materials may be in the form of a gas, liquid, or solid. Like an electro-energy cell, an electro-synthetic cell also requires a constant supply of reactants and a constant removal of products. Electro-synthetic cells may generally further require a constant input of electrical energy.

[0005] Examples of electro-synthetic cells include but are not limited to: water electrolysis cells, chlor-alkali cells, and cells for manufacturing hydrogen peroxide, ammonia, and the like.

[0006] Another feature of electro-synthetic or electro-energy cells is the large quantities of reactants and products that are typically involved in their operation. Such cells need to be constantly fed with substantial amounts of reactants, whilst significant volumes of products must be, simultaneously, constantly removed.

[0007] Large quantities of electrical energy are involved in operating electro -energy and electro-synthetic cells. Therefore, a key challenge in the development of these cells is to make them as energy efficient as possible during operation. This may be achieved, in part, by minimizing their electrical impedance. Impedance is the opposition that a cell circuit presents to an electrical current. One well-known method of minimizing impedance is to employ a cell architecture in which the anode and cathode electrodes of the cell are placed facing each other, as close as possible to each other, without touching (which would create a short circuit). The gap between the two electrodes should then, ideally, also be occupied by an electrolyte having the highest possible conductivity. In general, liquid electrolytes, as a class, have the highest conductivities of any electrolyte. An inter-electrode membrane / ionomer / diaphragm (also called a ‘separator’) may typically also be placed between the electrodes to prevent the electrodes from touching and to maintain the reactants consumed by and / or the products generated by each electrode separate from each other.

[0008] In industrial form, individual electro-synthetic and electro-energy liquid-gas cells may often be ‘stacked’ in electrical series with other individual cells to thereby create a ‘cell stack’. This is commonly achieved within a so-called ‘filter-press’ arrangement (also known as a ‘plate-and-frame’ arrangement). In such a configuration, individual cells having a substantially flat profile, may be stacked between two endplates that are compressed toward each other. This causes the intervening, stacked individual cells to: (i) make and maintain electrical contact with each other (in electrical series), and (ii) be securely held within the stack, to thereby: (iii) form a single electro-synthetic or electro-energy device, namely, a filter-press-type cell stack. The resulting cell stack is then, effectively, a single device that has the product output from all the incorporated cells, as well as their combined reactant consumption. In this way, large quantities of reactants and products may be accumulated into single, external, product and / or reactant streams, that are more easily managed than multiple smaller streams. Such a single device, or even a combination of multiple such single devices, may also be said to be components within an electro-synthetic or an electro-energy ‘cell’ (in the singular), despite the fact that they formally comprise multiple individual electro-synthetic or electro-energy cells. For example, such a single device may be said to be part of a single electro-synthetic or electroenergy cell, despite formally comprising of multiple individual electro-synthetic or electroenergy cells. This terminology may be routinely used when referring to an industrial electro-synthetic or electro-energy ‘cell’; i.e. an industrial electro-synthetic or electroenergy cell (in the singular) may comprise many individual electro-synthetic or electroenergy cells.

[0009] The engineering system, apparatus or arrangement that supports, manages, and / or controls such single, external, reactant and product streams, as well as the electrical current through the cell or cell stack, is known as the ‘balance-of-plant’, or ‘balance-of-stack’, or ‘balance-of-system’ .

[0010] The balance-of-plant of an electro-synthetic or electro-energy liquid-gas cell or cell stack may comprise a significant process engineering apparatus that consumes considerable energy, thereby affecting the overall energy efficiency of the full system. Moreover, the balance-of-plant may be more costly than the cells and cell stacks themselves, making it an economically important component of the overall electrosynthetic or electro-energy system. The balance-of-plant may be, additionally, critically important to ensuring that the cells / cell stacks operate reliably and safely and achieve their specified outputs.

[0011] The system components that manage the electrical energy going into or coming out of electro-energy and electro-synthetic cells form an integral part of the balance-of-plant. Because of the large quantities of electrical energy involved in operating electro-energyand electro-synthetic cells, a need exists for such power management components to be as energy efficient as possible in their operation. The higher their energy efficiency, the less wasteful of energy will be the overall system, with an accompanying lowering of operating costs and, in the case of an electro-synthetic cell, lower product costs.

[0012] An ‘industrial electrolyser’ as discussed herein, comprises a type of electrosynthetic cell, or assembly of individual electro-synthetic cells, or a stack of multiple individual electro-synthetic cells, or a combination of stacks that each comprise multiple individual electro-synthetic cells, that cumulatively requires a power input of greater than or equal to 50 kW power, and that uses electrical energy in the form of direct current (DC), to electrochemically drive a non-spontaneous chemical reaction in the individual cells present that results in the separation of chemical bonds. The word “lysis” means to separate or break, so electrolysis means “breakdown via electricity”. An ‘industrial electrolyser’ may typically further incorporate a balance-of-plant that supports, manages and / or controls the cells present. A non-limiting example of an industrial electrolyser is a water electrolyser of greater than or equal to 50 kW power that splits water into hydrogen gas and oxygen gas. Two types of water electrolysers are widely used industrially, namely, alkaline electrolysers and polymer electrolyte membrane (PEM) electrolysers.

[0013] Like other electro-synthetic cells, industrial electrolysers typically comprise multiple electrolysis cells ‘stacked’ together in one or more filter-press-type ‘cell stacks’ that is / are maintained and controlled by the surrounding ‘balance-of-plant’ engineering system. The power supply that feeds electrical power to the cell stacks of an industrial electrolyser is typically a key component of the balance-of-plant. The voltage, current, and power range produced by the power supply must typically be compatible with the voltage, current and power input required by the industrial electrolyser cell stack / s from beginning - of-life through to its end-of-life.

[0014] For the reasons given above, there is a need to optimise or improve the energy efficiency of the power supplies for industrial electrolyser cell stacks.

[0015] An ‘industrial power supply’, as described herein, is a rectifier and associated components, wherein the industrial power supply has been designed to convert alternating current (AC) (e.g. from the electrical grid) to direct current (DC), within a stationary, industrial setting. Preferably, though not exclusively, the industrial power supply has a power output of greater than or equal to 50 kW. Some non-limiting examples of industrial power supplies are provided in Table 1. It is to be understood that the listing in Table 1 is purely illustrative and not exhaustive. Other examples of industrial power supplies, not listed in Table 1, may exist.Table 1: Example industrial power supplies that are commercially available as at November 2023.

[0016] Commercially available industrial power supplies are typically configured to operate over a relatively wide range of voltages, currents, and power outputs, to be useful in many industrial applications. This maximises the volumes in which they are manufactured, thereby diminishing their cost. Industrial power supplies may be also termed power ‘converters’ as they may include one or several conversion stages. For example, some industrial rectifiers may only have a single AC-to-DC conversion stage. These converters often have a relatively small output voltage range (e.g., 540-850 V at 0-300 A).Other industrial rectifiers may have both an AC-to-DC conversion stage and a DC-to-DC conversion stage. These converters often have a larger output voltage range (e.g., 0-1000V at 0-300 A). Industrial converters can be split into two categories, single stage and multistage: Single stage converters are traditionally a six-pulse rectifier configuration with limited boost functionality. Multi-stage converters are traditionally a six -pulse rectifier configuration with a rectifier stage and a DC-to-DC conversion stage. Single stage converters may have a smaller output voltage range that is dependent on the input grid voltage. For example, an ABB ACS880 converter has an output voltage range of 540-860V with a standard 400 V input and a Siemens 6SL3300 converter has an output voltage range of 540-780 V with a standard 400 V input. However, multistage converters often have a wide output voltage range. For example, a RT22 module (supplied by Rectifier Technologies, https: / / www.rectifiertechnologies.com / ) and a CHARX module (supplied by Phoenix Contact, https: / / www.phoenixcontact.com / ) both have an output voltage range of 0-1000 V.

[0017] Commercially available industrial power supplies are generally designed to operate over a relatively wide range of voltages, currents, and power outputs. However, they are typically unable to achieve the highest possible peak energy efficiency at the specific voltages, currents, and power inputs required by industrial electrolyser cell stacks, at least when using standard transformers and switchgear. This may diminish the overall energy efficiency of the full industrial electrolyser system, including the power supply. While a bespoke, non-standard transformer can be designed to align the highest possible peak energy efficiency with the cell stack, this adds costs due to the low production volume of such a transformer. Non-standard or over-rated switchgear and other ancillaries may also need to be used.

[0018] Alternatively, an industrial power supply may be custom designed to constrain the voltage, current, and power range to exactly what the industrial electrolyser needs. Such a power supply may achieve the highest possible energy efficiency when powering the industrial electrolyser (without the need for non-standard transformers and switchgear). However, such custom engineering may typically limit the industrial utility of the industrialpower supply, restricting the volumes in which such an industrial power supply may be manufactured. The resulting low manufacturing volume may typically increase the cost of the power supply, often substantially so, as the sunk development costs must be amortized over a smaller production volume.

[0019] Accordingly, compromises involving energy efficiency and / or cost may be unavoidable when selecting a power supply for an industrial electrolyser. New approaches are needed to avoid such dilemmas.

[0020] Industrial power supplies may be air-cooled or liquid cooled. Liquid cooling of industrial electrical power supplies is generally more effective than air cooling because the specific heat of liquid water is about 4,200 J / (kg°C), which is higher than the specific heat of air at 1,005 J / (kg°C). Liquid cooling can be more advantageous over air-cooling in industrial power supplies. For example, liquid cooling provides a more efficient transfer of heat out of the device, thereby allowing it to be operated at a higher capacity and generate more heat. Further, there can be reduced audible noise due to the absence of fans used for cooling purposes; and reduced need for periodic maintenance as there is no need to replace air filters. The converter can be designed to be resistant to the ingress of dust, meaning that the internal components will not be exposed to dirt and dust. This may potentially increase the lifespan of the power supply, particularly when operating in harsh environments. Still further, the heat can be recovered using a heat recovery system, which is advantageous in certain industries; and there can be reduced substation air-conditioning costs. Accordingly, an increasing number of industrial power supplies are liquid cooled.

[0021] With liquid cooling, a base plate or base structure, the liquid cooling system which is heated by the internal components of the power supply, is typically kept at a steady temperature by circulating a cooling fluid through, about, or around it. The cooling liquid may be water, or a mixture of water and another fluid, such as a 50% water, 50% glycol mix. In industrial power supplies that are liquid cooled, the base plate or base structure is normally maintained below a maximum coolant operating temperature (according to the manufacturer’s ratings or specifications) of less than 60 °C, less than 59 °C, less than 58 °C, less than 57 °C, less than 56 °C, less than 55 °C, less than 54 °C, less than 53 °C, lessthan 52 °C, less than 51 °C, or less than 50 °C, for example at about 45 °C. That is, the liquid cooling system may be designed to remove heat at less than 60 °C, less than 59 °C, less than 58 °C, less than 57 °C, less than 56 °C, less than 55 °C, less than 54 °C, less than 53 °C, less than 52 °C, less than 51 °C, or less than 50 °C in such systems.

[0022] During operation, industrial electrolyser cell stacks may typically produce considerable heat that must be removed. Industrial electrolyser cell stacks must typically be continuously maintained at an operating temperature of greater than or equal to 60 °C, such as, for example, at about 80-90 °C. That is, the heat produced by such stacks must typically be removed at greater than or equal to 60 °C. Liquid cooling is typically used to cool industrial electrolysers and maintain them at their operating temperature of greater than or equal to 60 °C.

[0023] The temperature characteristics of the liquid cooling required in an industrial electrolyser may therefore be different to the temperature characteristics of the liquid cooling required in an industrial power supply. Therefore, two separate cooling systems are needed. The presence of two cooling systems may diminish the overall energy efficiency and increase the cost of the full industrial electrolyser system, including the power supply. Alternative approaches are needed to improve the energy efficiency of the full industrial electrolyser system, including the power supply, and improve the costeffectiveness of industrial electrolyser power supplies.

[0024] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.SUMMARY

[0025] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify all of the key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0026] The inventors have surprisingly discovered that the above challenges may be addressed and significantly ameliorated by using a traction inverter, including but not limited to an automotive traction inverter, to power an industrial electrolyser. The direction of operation of the traction inverter can be reversed to power the industrial electrolyser, wherein the cell stack / s of the industrial electrolyser have been configured to require voltage, current, and power ranges that substantially match the voltage, current, and power ranges produced by the traction inverter. That is, traction inverters, including automotive traction inverters, have surprisingly been found to avoid the compromises involving energy efficiency and / or cost of industrial electrolyser operation described earlier, if the cell stack / s of the industrial electrolyser can be and are configured to require voltage, current, and power ranges that substantially match the voltage, current, and power ranges produced by the traction inverter when the traction inverter is operated in the reverse direction.

[0027] A ‘traction inverter’, as discussed herein, is a device and associated components, with a power output, that, in normal operation, converts direct current (DC) (e.g. from a battery) to alternating current (AC) (e.g. for a motor) within a non-stationary, moving vehicle such as an automobile, an aircraft, or similar means of transport. Preferably, though not exclusively, a traction inverter has a power output of great than or equal to 50 kW. Preferably, though not exclusively, the power output of a traction inverter is intended to or designed to propel the motion of a non-stationery moving vehicle. An ‘automotive traction inverter’ as discussed herein, is a traction inverter that is specifically intended to or designed to power an electric motor that propels an electric vehicle (EV) automobile.

[0028] Traction inverters are similar to conventional inverters, such as solar inverters, insofar as, in normal operation, they convert DC electrical energy to AC electrical energy. However, traction inverters are different to conventional inverters in that conventional inverters are designed for use in stationary, fixed locations. It would generally be unusual and counter-intuitive to deploy inverters designed for mobile applications in a stationary, fixed application because this would be explicitly outside of the design parameters. In this case however, the inventors have surprisingly discovered that such an unexpected application may solve or significantly ameliorate the problems referred to above.

[0029] According to a first aspect, the invention provides a system for supplying electrical power to an electro-synthetic cell, the system comprising: an electro-synthetic cell; and, a traction inverter electrically connected to the electro-synthetic cell, the traction inverter comprising: a control system, wherein the control system is configured to operate the traction inverter in reverse such that an alternating current (AC) input to the traction inverter is converted into a direct current (DC) output from the traction inverter to power the electro-synthetic cell.

[0030] Preferably, but not exclusively, the electro-synthetic cell is an industrial electrolyser.

[0031] Preferably but not exclusively, the traction inverter is an automotive traction inverter.

[0032] Preferably, but not exclusively, the traction inverter comprises a liquid cooling system with a coolant.

[0033] In some preferred embodiments, the liquid cooling system and the coolant are common to both the traction inverter and the electro-synthetic cell. In other preferred embodiments, the coolant is in fluid communication with the traction inverter and the electro-synthetic cell.

[0034] During operation, the coolant preferably has a coolant temperature, which falls within a range, the maximum of which (i.e. the maximum coolant temperature) is greater than or equal to 50 °C, greater than or equal to 51 °C, greater than or equal to 52 °C, greater than or equal to 53 °C, greater than or equal to 54 °C, greater than or equal to 55 °C, greater than or equal to 56 °C, greater than or equal to 57 °C, greater than or equal to 58 °C, or greater than or equal to 59 °C, or greater than or equal to 60 °C.

[0035] During operation, the system preferably has a power density of greater than or equal to 5 kW / litre, greater than or equal to 6 kW / litre, greater than or equal to 7 kW / litre, greater than or equal to 8 kW / litre, greater than or equal to 9 kW / litre, greater than or equal to 10kW / litre, greater than or equal to 12 kW / litre, greater than or equal to 14 kW / litre, or greater than or equal to 18 kW / litre.

[0036] During operation, the system preferably has a specific power greater than or equal to 5 kW / kg, greater than or equal to 6 kW / kg, greater than or equal to 7 kW / kg, greater than or equal to 8 kW / kg, greater than or equal to 9 kW / kg, greater than or equal to 10 kW / kg, greater than or equal to 12 kW / kg, greater than or equal to 14 kW / kg, or greater than or equal to 18 kW / kg.

[0037] Preferably, the maximum coolant temperature may be greater than or equal to 60 °C, greater than or equal to 59 °C, greater than or equal to 58 °C, greater than or equal to 57 °C, greater than or equal to 56 °C, greater than or equal to 55 °C, greater than or equal to 54 °C, greater than or equal to 53 °C, greater than or equal to 52 °C, greater than or equal to 51 °C, or greater than or equal to 50 °C. Preferably, the traction inverter may have a power density greater than or equal to 5 kW / litre, greater than or equal to 6 kW / litre, greater than or equal to 7 kW / litre, greater than or equal to 8 kW / litre, greater than or equal to 9 kW / litre, greater than or equal to 10 kW / litre, greater than or equal to 12 kW / litre, greater than or equal to 14 kW / litre, or greater than or equal to 18 kW / litre. Preferably, the traction inverter may have a specific power greater than or equal to 5 kW / kg, greater than or equal to 6 kW / kg, greater than or equal to 7 kW / kg, greater than or equal to 8 kW / kg, greater than or equal to 9 kW / kg, greater than or equal to 10 kW / kg, greater than or equal to 12 kW / kg, greater than or equal to 14 kW / kg, or greater than or equal to 18 kW / kg.

[0038] The control system of the traction inverter may be adapted from an original configuration to operate the traction inverter in reverse to power the electro-synthetic cell. The control system may also be replaced with a replacement control system having an alternative configuration to operate the traction inverter in reverse to power the electrosynthetic cell.

[0039] The system preferably further comprises an interfacing hardware. The interfacing hardware may be adapted from an original configuration to enable connection to the electro-synthetic cell, or the interfacing hardware may be replaced by a replacementinterfacing hardware having an alternative configuration to enable connection to the electro-synthetic cell.

[0040] The system preferably further comprises a pre-charge circuit to provide power to the electro-synthetic cell. The pre-charge circuit may be adapted from an original configuration to provide power to the electro-synthetic cell, or the pre-charge circuit may be replaced by a replacement pre-charge circuit having an alternative configuration to provide power to the electro-synthetic cell.

[0041] In some embodiments, the control system of the traction inverter is adapted or replaced to operate the traction inverter in reverse to power the electro-synthetic cell, and the interfacing hardware of the traction inverter is adapted or replaced to enable connection to the electro- synthetic cell; and the pre-charge circuit of the traction inverter is adapted or replaced to power the electro-synthetic cell,

[0042] The control system may be adapted to detect if the alternating current (AC) input to the traction inverter has three-phase voltage waveforms and if so to convert the three- phase voltage waveforms into the direct current (DC) output from the traction inverter.

[0043] In some embodiments, the pre-charge circuit charges up a load voltage of the electro-synthetic cell to a DC bus capacitor voltage in the traction inverter to prevent a large in-rush current at start-up of the system.

[0044] According to a second aspect, the invention provides a traction inverter electrically connected to an electro-synthetic cell, the traction inverter comprising a control system, wherein the control system is configured to operate the traction inverter in reverse such that alternating current (AC) input to the traction inverter is converted into direct current (DC) output from the traction inverter to power the electro-synthetic cell.

[0045] According to a third aspect, the invention provides a traction inverter used in the system of the first aspect.

[0046] According to a fourth aspect, the invention provides a traction inverter connected to an industrial electrolyser, the traction inverter comprising: a control system, wherein the control system is configured to operate the traction inverter in reverse such that alternating current (AC) is converted into direct current (DC) to power the industrial electrolyser, wherein the traction inverter comprises a liquid cooling system, wherein the maximum coolant temperature is greater than or equal to 50 °C, wherein the power density of the traction inverter is greater than or equal to 5 kW / litre, wherein the traction inverter has a specific power greater than or equal to 5 kW / kg, wherein the control system of the traction inverter is adapted or replaced to operate the traction inverter in reverse to power the industrial electrolyser, and wherein the interfacing hardware of the traction inverter is adapted or replaced to enable connection to the electrolyser; and / or wherein the pre-charge circuit of the traction inverter is adapted or replaced to power the industrial electrolyser. The maximum coolant temperature is preferably greater than or equal to 60 °C.

[0047] According to a fifth aspect, the invention provides a traction inverter connected to an industrial electrolyser, the traction inverter comprising: a control system, wherein the control system is configured to operate the traction inverter in reverse such that alternating current (AC) is converted into direct current (DC) to power the industrial electrolyser, wherein the traction inverter comprises a liquid cooling system, wherein the maximum coolant temperature is greater than or equal to 60 °C, wherein the power density of the traction inverter is greater than or equal to 18 kW / litre, wherein the traction inverter has a specific power greater than or equal to 18 kW / kg, wherein the control system of the traction inverter is adapted or replaced to operate the traction inverter in reverse to power the industrial electrolyser, and / or wherein the interfacing hardware of the traction inverter is adapted or replaced to enable connection to the electrolyser; and / or wherein the pre-charge circuit of the traction inverter is adapted or replaced to power the industrial electrolyser, wherein the control system is replaced with a control system to detect incoming three-phase voltage waveforms and convert them into a controllable DC output, and / or wherein the precharge circuit is replaced to charge up the industrial electrolyser load voltage to the DC bus capacitor voltage in the traction inverter to prevent a large in-rush current at start-up.

[0048] According to a sixth aspect, the invention provides a method for powering an electro-synthetic cell, the electro-synthetic cell comprising: at least one electrode requiring a supply of direct current (DC) for operation of the electro-synthetic cell; a traction inverter electrically connected to the electro-synthetic cell, the method comprising: operating the traction inverter in reverse such that alternating current (AC) input to the traction inverter is converted into direct current (DC) output from the traction inverter and supplied to the at least one electrode.

[0049] Preferably, the electro-synthetic cell is an industrial electrolyser.

[0050] Preferably, the traction inverter comprises a control system, and the control system is configured to operate the traction inverter in reverse.

[0051] The method preferably comprises configuring the electro-synthetic cell and / or the at least one electrode to require a voltage, and / or a current, and / or a power input range that are substantially similar to a voltage, and / or a current and / or a power output range of the traction inverter.

[0052] The traction inverter is preferably an automotive traction inverter.

[0053] Multiple electro-synthetic cells may be provided in one or more cell stacks.

[0054] Configuring the at least one electrode preferably involves configuring a size of the at least one electrode to provide for a selected range of currents. Configuring an individual cell of the multiple electro-synthetic cells preferably comprises configuring a number of the individual cells in the one or more cell stacks to provide for a selected range of voltages. Configuring an individual cell of the multiple electro-synthetic cells preferably comprises optimizing the one or more cell stack to avoid or minimise the incidence or effect of shunt or bypass currents to provide for a selected range of power inputs.

[0055] The control system preferably enables constant reverse operation of the traction inverter. The method preferably involves detecting, by the control system, if the alternatingcurrent (AC) input to the traction inverter has three-phase voltage waveforms and, if so, converting the three-phase voltage waveforms into the direct current (DC) output from the traction inverter. The method may further include a pre-charge circuit to charge up a load voltage of the electro-synthetic cell to a DC bus capacitor voltage in the traction inverter to prevent a large in-rush current at start-up of the electro-synthetic cell.

[0056] According to the seventh aspect, the invention provides the system, the traction inverter, or the method of the previous aspects, wherein the traction inverter has a power output of greater than or equal to 50 kW.

[0057] According to the eighth aspect, the invention provides the system, the traction inverter, or the method of the previous aspects, wherein the traction inverter has been intended to or designed to propel a non-stationery moving vehicle.

[0058] Traction inverters may be configured to operate in reverse. That is, traction inverters may be configured to convert alternating current (AC) into direct current (DC). For example, during regenerative braking in an electric motor vehicle, an automotive traction inverter may convert AC power (e.g. from a spinning electric vehicle motor) into DC power (e.g. stored in the electric vehicle batteries).

[0059] Traction inverters may be distinguished from industrial power supplies in several important aspects that are described below.

[0060] Firstly, traction inverters are specifically designed to convert direct current (DC) to alternating current (AC) in non-stationary, vehicular settings. The nature of mobile applications and their associated issues, for example the issue of the limited space and weight, the requirement for minimization of space and weight in mobile applications (in which space and weight is at a premium), means that the efficiency, weight, and size of the traction drive inverter have been key considerations in the design of traction inverter technology. By contrast, the weight, and volume of industrial power supplies is not as critical due to the stationary nature of typical use-cases for industrial power supply technology. Thus, traction inverters may, secondly, also routinely be far more compact thanindustrial power supplies, this being a key requirement in non-stationary, vehicular settings but of much lower importance in stationary, industrial settings. For example, traction inverters may routinely exhibit high power densities of greater than or equal to 5 kW / litre, greater than or equal to 6 kW / litre, greater than or equal to 7 kW / litre, greater than or equal to 8 kW / litre, greater than or equal to 9 kW / litre, greater than or equal to 10 kW / litre, greater than or equal to 12 kW / litre, greater than or equal to 14 kW / litre, or greater than or equal to 18 kW / litre. They may also exhibit high specific powers of greater than or equal to 6 kW / kg, greater than or equal to 6 kW / kg, greater than or equal to 7 kW / kg, greater than or equal to 8 kW / kg, greater than or equal to 9 kW / kg, greater than or equal to 10 kW / kg, greater than or equal to 12 kW / kg, greater than or equal to 14 kW / kg, or greater than or equal to 18 kW / kg. Thirdly, because of their compact design, traction inverters must typically be liquid cooled, with the temperature of the liquid coolant during operation being notably higher than in industrial power supplies. For example, traction inverters may routinely have a maximum coolant operating temperature of greater than or equal to 60 °C, such as, for example, -70-90 °C. Traction inverters may, fourthly, typically be configured to output narrower ranges of voltage, current, and power than industrial power supplies, during continuous operation, since traction inverters are designed for very specific, mobile applications, for example powering a particular electric vehicle, which may only need high power for short periods of time during acceleration of the vehicle. Such narrower ranges may provide for higher peak energy efficient operation than can be achieved with the wider ranges that may be typically employed by industrial power supplies. Traction inverters may, fifthly, typically utilise high performance electronic components such as insulated gate bipolar transistor (IGBT) and / or silicon carbide (SiC) switches; traction inverters based on such components are readily commercially available. Such components may, sixthly, allow for higher energy efficiencies than can be achieved with older, less sophisticated components. There is, seventhly, therefore also a better developed supply chain for components used in high efficiency designs within traction inverters when compared with industrial power supplies due to the proliferation of the electric vehicle market. Eighthly, traction inverters have a long history of utilizing high performance electronic components, such as IGBT and SiC switches. Their operation with such components and high efficiency designs has been thoroughly developed into a maturetechnology that is now well documented and highly reliable. By contrast, the requirement for the optimization of high efficiency and compact industrial power supply designs is a more recent trend, with a shorter history. The shorter history indicates a potentially smaller amount of accurate reliability data when compared to that with traction drives. Ninthly, traction inverters such as but not limited to automotive traction inverters, may be manufactured in much larger production runs than industrial power supplies. For example, automotive traction inverters may be manufactured in hundreds of thousands of units per year, this being not unusual in the automotive industry. Such high-volume manufacturing may result in lower costs / prices per unit than is possible for the industrial power supplies that are manufactured on smaller scale.

[0061] The inventors have surprisingly found that: (a) if the cell stack / s of an industrial electrolyser can be designed and configured such that their voltage, current, and power requirements substantially match those of a traction inverter when it is operated in reverse, and (b) if the traction inverter may be adapted or altered to connect to and control the cell stack / s of an industrial electrolyser thus configured, then this may increase the comparative, overall energy efficiency and lower the overall cost of the full industrial electrolyser system, relative to the use of an industrial power supply.

[0062] Step (a) above may involve: configuring a size of the electrodes in the cell stack / s to provide for a particular range of currents, configuring the number of cells in the cell stack / s to provide for a particular range of voltages, and / or optimizing the size of the electrodes, the number of cells, and their configuration in the cell stack / s to avoid or minimise the incidence or effect of ‘shunt’ currents (also called ‘bypass’ currents) to provide for a particular range of power inputs.

[0063] Step (b) may involve:adapting or replacing the control system of the traction inverter to allow the traction inverter to provide DC power to operate the industrial electrolyser, adapting or replacing the interfacing hardware of the traction inverter to allow the traction inverter to provide power to operate the industrial electrolyser, adapting or replacing the control system to detect incoming three-phase voltage waveforms and convert them into a controllable DC output, and / or adapting or replacing a pre-charge circuit of the traction inverter to power the industrial electrolyser. Preferably, the pre-charge circuit is adapted or replaced to charge up the industrial electrolyser load voltage to the DC bus capacitor voltage in the traction inverter to prevent a large in-rush current at start-up.METHOD OF USE

[0064] There is further provided a method for powering an industrial electrolyser with a traction inverter, including an automotive traction inverter, operating in reverse, the method comprising:(1) configuring the individual cells and their electrodes in a cell stack of the industrial electrolyser to require voltages, currents, and power input ranges that are substantially similar to those that are produced by the traction inverter. This may involve configuring: the size of the electrodes in the cell stack / s to provide for a particular range of currents; the number of cells in the cell stack / s to provide for a particular range of voltages; and / or optimizing the size of the electrodes, the number of cells, and their configuration in the cell stack / s to avoid or minimise the incidence or effect of ‘shunt’ currents (also called ‘bypass’ currents) to provide for a particular range of power inputs;(2) adapting or replacing the control system and / or the interface hardware and / or other components of the traction inverter. For example, the control system may be changed to enable constant reverse operation of the traction inverter. In another example, the interface hardware of the traction inverter may be changed. In a further example, a new control system or interface may be retrofitted; connecting the traction inverter to the industrial electrolyser; and(3) passing an electrical current from the traction inverter into the industrial electrolyser.ADDITIONAL ASPECTS

[0065] There is further provided means to simplify step (1) above, these means involving: employing industrial electrolyser cell stack / s capable of high energy efficiency, including but not limited to the cell stacks described in International Patent Publication Nos. W02022056603, W02022056604, W02022056605, and W02022056606, which are hereby incorporated by references. This may improve the overall energy efficiency of the full industrial electrolyser system, including the power supply; avoiding ‘shunt’ currents (also called ‘bypass’ currents) in the industrial electrolyser cell stack / s using techniques including but not limited to those described in International Patent Publication Nos. W02022056603, W02022056604, W02022056605, and W02022056606, which are hereby incorporated by references.

[0066] In the context of the present invention, the words “comprise”, “comprising” and the like are to be construed in their inclusive, as opposed to their exclusive, sense, that is in the sense of “including, but not limited to”.

[0067] The invention is to be interpreted with reference to the at least one of the technical problems described or affiliated with the background art. The present aims to solve or ameliorate at least one of the technical problems and this may result in one or moreadvantageous effects as defined by this specification and described in detail with reference to the preferred embodiments of the present invention.BRIEF DESCRIPTION OF THE FIGURES

[0068] Figure 1 schematically depicts an example embodiment wherein the traction inverter and a cell stack of an industrial electrolyser have separate liquid cooling loops.

[0069] Figure 2 schematically depicts an example embodiment wherein the traction inverter and a cell stack of an industrial electrolyser have a common liquid cooling loop.

[0070] Figure 3 schematically depicts an example method of applying embodiments of the invention.DESCRIPTION OF THE INVENTION

[0071] Preferred embodiments of the invention will now be described with reference to the accompanying drawings and non-limiting examples.

[0072] In this document, the term ‘user’ refers to the person filing or wishing to file a patent application. The term ‘agent’ refers an appropriately skilled professional capable of drafting and filing patent applications. In most cases, the agent is a patent attorney, patent attorney firm, or lawyer skilled with patent prosecution.DEFINITIONS

[0073] An ‘electro-energy cell’, as discussed herein, is an electrochemical cell that generates electrical power continually or continuously, over indefinite periods of time, for use outside of the cell. Electro-energy cells may require a constant external supply of reactants during operation. The products of the electrochemical reaction may be also constantly removed from such cells during operation. An electro-energy cell may be aliquid-gas cell. An example of an electro-energy cell is a hydrogen-oxygen fuel cell. This example is also a liquid-gas cell.

[0074] An ‘electro-synthetic cell’, as discussed herein, is an electrochemical cell that manufactures one or more chemical materials continually or continuously, over indefinite periods of time, for use outside the cell. The chemical materials may be in the form of a gas, liquid, or solid. Like an electro-energy cell, an electro-synthetic cell may also require a constant supply of reactants and a constant removal of products during operation. Electrosynthetic cells may generally further require a constant input of electrical energy during operation. An electro-synthetic cell may be a liquid-gas cell. An example of an electrosynthetic cell is a water electrolysis cell. This example is also a liquid-gas cell.

[0075] Electro-energy and electro-synthetic cells, as discussed herein, differ from other types of electrochemical cells, such as batteries, sensors and the like, in that they do not incorporate within the cell body all / some of the reactants they require to operate, nor all / some of the products they generate during operation. These may, instead, be constantly brought in from, or removed to the outside of the cell during operation. For example, electro-energy cells are distinguished from galvanic cells in that galvanic cells store their reactants and products within the cell body. Unlike a battery, an electro-energy cell does not store chemical or electrical energy within it. Similarly, while some electrochemical sensors may consume reactants and generate products in limited quantities during the sensing operation, all / some of these are stored within the cell body itself.

[0076] The term ‘cell’ as used herein may refer to an individual cell in the singular or to a collection of individual cells in the plural. For example, an electro-energy or electrosynthetic ‘cell’ may refer to a single, individual electro-energy or electro-synthetic cell, or it may refer to a plurality of individual electro-energy or electro-synthetic cells combined into a single device.

[0077] An ‘industrial electrolyser’ as discussed herein, is defined to comprise a type of electro-synthetic cell, or an assembly of individual electro-synthetic cells, or a stack of multiple individual electro-synthetic cells, or a combination of stacks that each compriseof multiple individual electro-synthetic cells, of cumulatively greater than or equal to 50 kW power, that employs electrical energy in the form of a direct current (DC) to electrochemically drive a non-spontaneous chemical reaction within the individual electrosynthetic cells present that results in the separation of chemical bonds. The word "lysis" means to separate or break, so electrolysis means "breakdown via electricity". An ‘industrial electrolyser’ may typically further incorporate a balance-of-plant that supports, manages and / or controls the cells present. An example of an industrial electrolyser is a water electrolyser of greater than or equal to 50 kW power that splits water into hydrogen gas and oxygen gas. Two types of water electrolysers are widely used industrially, namely, alkaline electrolysers and polymer electrolyte membrane (PEM) electrolysers.

[0078] An ‘industrial power supply’, as discussed herein, is defined as a rectifier and associated components, having a power output, wherein the industrial power supply has been designed to convert alternating current (AC) to direct current (DC), preferably within a stationary, industrial setting. Preferably, though not exclusively, the industrial power supply has a power output of greater than or equal to 50 kW.

[0079] A ‘traction inverter’, as discussed herein, is defined as a device and associated components, with a power output, configured to convert direct current (DC) to alternating current (AC) within a non-stationary, moving vehicle such as an automobile, an aircraft, or similar means of transport. Preferably, though not exclusively, a traction inverter has a power output of greater than or equal to 50 kW. Preferably, though not exclusively, the power output of a traction inverter is intended to or designed to propel the motion of the non-stationery moving vehicle. An ‘automotive traction inverter’ is herein defined as a traction inverter that is specifically intended to or designed to power an electric motor that propels an electric vehicle (EV) automobile.

[0080] The terms ‘maximum coolant temperature’ or ‘maximum coolant operating temperature’, as used herein, are defined as the maximum temperature that may be reached by the liquid coolant during continuous or continual use of a liquid-cooled device, according to the manufacturer’s ratings or specifications, or in practical application. The‘coolant’ is defined as the cooling liquid, which may be water, a mixture of water and another fluid, such as a 50% water, 50% glycol mix, or a coolant liquid of any type.

[0081] The “power density” of a power supply (including, but not limited to, an industrial power supply, a traction inverter, or an automotive traction inverter) is herein defined as the power per unit volume of the power supply (which may also be termed the ‘volumetric power density’).

[0082] The “specific power” of a power supply (including, but not limited to, an industrial power supply, a traction inverter, or an automotive traction inverter) is herein defined as the power per unit mass of the power supply (which may also be termed the ‘gravimetric power density’).EXAMPLE EMBODIMENTS OF THE INVENTION

[0083] The inventors have surprisingly discovered that employing a commercially available traction inverter, operating in reverse, to power an industrial electrolyser may result in higher energy efficiencies and lower overall system costs, compared to the use of a commercially available industrial power supply if: (a) the cell stack / s of an industrial electrolyser can be designed and configured such that their voltage, current, and power requirements substantially match, but never exceed those of a traction inverter when it is operated in reverse, and (b) the traction inverter may be adapted or altered to connect to and control the cell stack / s of an industrial electrolyser thus configured.

[0084] Traction inverters may be distinguished from industrial power supplies in being specifically designed to convert direct current (DC) to alternating current (AC) in non- stationary, vehicular settings, whereas industrial power supplies are designed to convert alternating current (AC) to direct current (DC) in stationary, non-vehicular settings.

[0085] Traction inverters may be configured to operate in reverse; that is, to convert alternating current (AC) into direct current (DC). For example, during regenerative braking in an electric motor vehicle, an automotive traction inverter may convert AC power (e.g.from a spinning electric vehicle motor) into DC power (e.g. stored in the electric vehicle batteries). Regenerative braking is essentially an energy recovery mechanism. During regenerative braking, the kinetic energy of a moving vehicle or object is converted into a form that can be either used immediately or stored until needed. In this mechanism, the electric traction motor utilises the momentum of the vehicle to recover energy that would otherwise be lost as heat to the brake discs. In contrast, in conventional braking systems, excess kinetic energy is converted to unwanted and wasted heat due to friction in the brakes. With rheostatic brakes, kinetic energy is recovered by using electric motors as generators but is dissipated as heat in resistors. This is designed to improve the overall energy efficiency of the vehicle. Operating a traction inverter in reverse refers to a three- phase supply input being converted into a direct current output. A new control system may be required to facilitate the reverse conversion. A pre-charge circuit can be repurposed to slowly ramp up the current when the load (an industrial electrolyser, in the case of the present invention) is connected to the DC output terminal of the converter.

[0086] When operating in traction inverter mode, the control system can use a motor control algorithm to control the inverter to produce a controllable three-phase voltage that best controls the traction motor. When the traction inverter is operated in reverse, this control system can be replaced with a control system that detects incoming three-phase voltage waveforms and can convert these into a controllable DC output.

[0087] The capacitor inside a traction inverter may require slow charging of the battery prior to connection to prevent the occurrence of a large current that could potentially damage the automotive battery or capacitor. In traction inverter mode, at start-up, the capacitor can be slowly charged to the battery voltage before outputting current to the motor. When the traction inverter is operating in reverse mode, the pre-charge circuit may be operated to give soft-starting capability to slowly charge up the industrial electrolyser load voltage to the capacitor voltage. This can be done to avoid a large in-rush current at start-up.

[0088] For the reasons discussed below, traction inverters, including automotive traction inverters, have surprisingly been found to avoid the compromises discussed in thebackground section, involving energy efficiency and / or cost of industrial electrolyser operation.

[0089] Traction inverters are designed for very specific, mobile applications. Traction inverters may typically be configured to output narrower ranges of continuous voltage, current, and power than some industrial power supplies, including when the traction inverters operate in reverse. That is, when converting AC current to DC current. Such narrower ranges may provide for higher peak energy efficient operation than can be achieved with the wider ranges that may be typically employed by industrial power supplies. The inventors have surprisingly found that if the cell stack / s of an industrial electrolyser are designed such that their voltage, current, and power requirements substantially match those of a traction inverter when it is operated in reverse, then this may increase the comparative, overall energy efficiency of the full industrial electrolyser system, including the power supply.

[0090] Traction inverters may, moreover, typically be readily commercially available at a substantially lower cost than comparable industrial power supplies, as traction inverters may be produced in very high volumes. For example, a traction inverter used in an electric vehicle may be produced in volumes of hundreds of thousands of units per year, which may far exceed the production run of any industrial power supply. This feature may reduce the comparative, overall cost of the full industrial electrolyser system, including the power supply.

[0091] A traction inverter may be adapted to operate in reverse, to convert AC current to DC current. That is, adaptation may involve changes to the control system and and / or the interface hardware and / or other components of the traction inverter. For example, the control system may be changed to enable constant reverse operation of the traction inverter. In another example, the interface hardware of the traction inverter may be changed. In a further example, a new control system or interface may be retrofitted.

[0092] Accordingly, employing a commercially available traction inverter, operating in reverse, to power an industrial electrolyser may result in higher energy efficiencies andlower costs overall, compared to the use of a commercially available industrial power supply.

[0093] Using a traction inverter, including an automotive traction inverter, to power an industrial electrolyser may, additionally, avoid the aforementioned need for two different cooling systems, for the following reasons:

[0094] Traction inverters are typically liquid cooled. Unlike industrial power supplies, traction inverters may routinely employ a maximum coolant operating temperature of greater than or equal to 60°C, greater than or equal to 59 °C, greater than or equal to 58 °C, greater than or equal to 57 °C, greater than or equal to 56 °C, greater than or equal to 55 °C, greater than or equal to 54 °C, greater than or equal to 53 °C, greater than or equal to 52 °C, greater than or equal to 51 °C, or greater than or equal to 50 °C, such as, for example, about 70 °C to about 90°C, this being generally required in non-stationary, mobile applications.

[0095] The maximum coolant temperature required in an industrial electrolyser (greater than or equal to 60°C) may be the same as, or similar to the maximum coolant temperature of a traction inverter. It may be possible to have a single liquid cooling system for both the industrial electrolyser and the traction inverter. Such an arrangement may provide for a comparative improvement in the overall energy efficiency and decrease in the cost of the full industrial electrolyser system, including the power supply.

[0096] Traction inverters, including automotive traction inverters, may potentially be suitable power systems for industrial electrolysers, for the following reasons:

[0097] Traction inverters, which are routinely commercially available, may typically utilise high performance electronic components such as Insulated Gate Bipolar Transistor (IGBT) and silicon carbide (SiC) switches. Such components may allow for higher energy efficiencies that cannot be achieved with older, less sophisticated components. Issue such as ‘range anxiety’, which is experienced with many electric vehicle owners, means that the efficiency, weight, and volume of the traction drive inverter have been key considerationswith the design of this technology. In contrast, the efficiency, weight and volume of industrial power supplies has not been as critical due to the stationary nature of typical usecases for this technology and the fact that previous industrial application did not call for ultra-efficient drives. There is, accordingly, a better developed supply chain for components used in high efficiency designs within traction inverters when compared with industrial power supplies.

[0098] Moreover, traction inverters have a long history of utilizing high performance electronic components, such as Insulated Gate Bipolar Transistor (IGBT) and silicon carbide (SiC) switches. Their operation with such components and high efficiency designs has been thoroughly developed into a mature technology that is well documented and highly reliable. By contrast, the requirement for the optimization of high efficiency and compact industrial power supply designs is a more recent trend, with a shorter history. The shorter history indicates a potentially smaller amount of accurate reliability data when compared to that with traction drives.

[0099] Traction inverters may be highly compact, as is typically needed in non-stationary, mobile applications. Traction inverters may be, for example, far more compact than conventional industrial power supplies. The use of traction inverters to power an industrial electrolyser may therefore provide a comparable reduction in the overall footprint of the full industrial electrolyser system, including the power supply. The reason for the compact dimensions and high-power density of automotive traction inverters is largely because automobile companies have been attempting to reduce the drive weight and volume to improve vehicle performance and range. Power density is not as critical in stationary industrial applications, so industrial power supplies have typically not been optimised as much in this respect.

[0100] The invention therefore provides a traction inverter operated in reverse to provide power to operate an industrial electrolyser.

[0101] Preferably but not exclusively, the traction inverter is an automotive traction inverter.

[0102] Preferably but not exclusively, the traction inverter has a liquid cooling system, and the maximum coolant temperature, during operation, is greater than or equal to 60 °C. In other examples, the maximum coolant temperature is greater than or equal to 59 °C, greater than or equal to 58 °C, greater than or equal to 57 °C, greater than or equal to 56 °C, greater than or equal to 55 °C, greater than or equal to 54 °C, greater than or equal to 53 °C, greater than or equal to 52 °C, greater than or equal to 51 °C, or greater than or equal to 50 °C.

[0103] There is provided a traction inverter operating in reverse to power an industrial electrolyser, wherein the traction inverter and the industrial electrolyser have a common liquid cooling system and the maximum coolant temperature is greater than or equal to 60 °C. In other examples, the maximum coolant temperature is greater than or equal to 59 °C, greater than or equal to 58 °C, greater than or equal to 57 °C, greater than or equal to 56 °C, greater than or equal to 55 °C, greater than or equal to 54 °C, greater than or equal to 53 °C, greater than or equal to 52 °C, greater than or equal to 51 °C, or greater than or equal to 50 °C. In another aspect, a liquid coolant of the liquid cooling system may be in fluid communication with both the traction inverter and the industrial electrolyser.

[0104] In another aspect, the traction inverter has a power density of greater than or equal to 5 kW / litre. In other examples, the traction inverter has a power density of greater than or equal to 6 kW / litre, greater than or equal to 7 kW / litre, greater than or equal to 8 kW / litre, greater than or equal to 9 kW / litre, greater than or equal to 10 kW / litre, greater than or equal to 12 kW / litre, greater than or equal to 14 kW / litre, or greater than or equal to 18 kW / litre.

[0105] In still another aspect, the traction inverter has a specific power of greater than or equal to 5 kW / kg. In other examples, the traction inverter has a specific power of greater than or equal to 6 kW / kg, greater than or equal to 7 kW / kg, greater than or equal to 8 kW / kg, greater than or equal to 9 kW / kg, greater than or equal to 10 kW / kg, greater than or equal to 12 kW / kg, greater than or equal to 14 kW / kg, or greater than or equal to 18 kW / kg.

[0106] In a further aspect, the control system of the traction inverter is adapted or replaced to allow the traction inverter to power the industrial electrolyser.

[0107] In a still further aspect, the interfacing hardware of the traction inverter is adapted or replaced to allow the traction inverter to power the industrial electrolyser.

[0108] Preferably, the control system of the traction inverter is adapted or replaced to allow the traction inverter to provide power to operate the industrial electrolyser, wherein the interfacing hardware of the traction inverter is adapted or replaced to allow the traction inverter to provide power to operate the industrial electrolyser.

[0109] In a further aspect, there is provided a traction inverter wherein a pre-charge circuit of the traction inverter is adapted to power the industrial electrolyser.

[0110] Preferably, a pre-charge circuit of the traction inverter is replaced to power the industrial electrolyser.

[0111] Preferably but not exclusively, the control system of the traction inverter is adapted or replaced to power the industrial electrolyser, and the interfacing hardware of the traction inverter is adapted or replaced to enable connection to the electrolyser; and wherein the pre-charge circuit of the traction inverter is adapted or replaced to power the industrial electrolyser.

[0112] In a still further aspect, there is provided a traction inverter wherein the control system is replaced with a control system to detect incoming three-phase voltage waveforms and convert them into a controllable DC output.

[0113] Preferably, the pre-charge circuit is replaced to charge up the industrial electrolyser load voltage to the DC bus capacitor voltage in the traction inverter to prevent a large in-rush current at start-up.

[0114] The inventors have therefore surprisingly found that: (a) if the cell stack / s of an industrial electrolyser can be designed and configured such that their voltage, current, and power requirements substantially match those of a traction inverter when it is operated in reverse, and (b) if the traction inverter may be adapted or altered to connect to and control the cell stack / s of an industrial electrolyser thus configured, then this may increase the comparative, overall energy efficiency and lower the overall cost of the full industrial electrolyser system, relative to the use of an industrial power supply.

[0115] Step (a) above may involve: configuring a size of the electrodes in the cell stack / s to provide for a particular range of currents, configuring the number of cells in the cell stack / s to provide for a particular range of voltages, and / or optimizing the size of the electrodes, the number of cells, and their configuration in the cell stack / s to avoid or minimise the incidence or effect of ‘shunt’ currents (also called ‘bypass’ currents) to provide for a particular range of power inputs.

[0116] Step (b) may involve: adapting or replacing the control system of the traction inverter to allow the traction inverter to provide power to operate the industrial electrolyser, adapting or replacing the interfacing hardware of the traction inverter to allow the traction inverter to provide power to operate the industrial electrolyser, adapting or replacing the control system to detect incoming three-phase voltage waveforms and convert them into a controllable DC output, and / oradapting or replacing a pre-charge circuit of the traction inverter to power the industrial electrolyser. Preferably, the pre-charge circuit is adapted or replaced to charge up the industrial electrolyser load voltage to a capacitor voltage in the traction inverter to prevent a large in-rush current at start-up.METHOD OF USE

[0117] There is further provided a method for powering an industrial electrolyser with a traction inverter, including an automotive traction inverter, operating in reverse, the method comprising:(1) configuring the individual cells and their electrodes in a cell stack of the industrial electrolyser to require voltages, currents, and power input ranges that are substantially similar to those of the traction inverter. This may involve configuring: the size of the electrodes in the cell stack / s to provide for a particular range of currents; the number of cells in the cell stack / s to provide for a particular range of voltages; and / or optimizing the size of the electrodes, the number of cells, and their configuration in the cell stack / s to avoid or minimise the incidence or effect of ‘shunt’ currents (also called ‘bypass’ currents) to provide for a particular range of power inputs;(2) adapting or replacing the control system and / or the interface hardware and / or other components of the traction inverter. For example, the control system may be changed to enable constant reverse operation of the traction inverter. In another example, the interface hardware of the traction inverter may be changed. In a further example, a new control system or interface may be retrofitted; connecting the traction inverter to the industrial electrolyser; and(3) passing an electrical current from the traction inverter into the industrial electrolyser.ADDITIONAL ASPECTS

[0118] There is further provided means to simplify step (1) above, these means involving: employing industrial electrolyser cell stack / s capable of high energy efficiency, including but not limited to the cell stacks described in International Patent Publication Nos. W02022056603, W02022056604, W02022056605, and W02022056606, which are hereby incorporated by references. This may improve the overall energy efficiency of the full industrial electrolyser system, including the power supply; avoiding ‘shunt’ currents (also called ‘bypass’ currents) in the industrial electrolyser cell stack / s using techniques including but not limited to those described in International Patent Publication Nos. W02022056603, W02022056604, W02022056605, and W02022056606, which are hereby incorporated by references.Table 2: Example Traction inverters as of November 2023.HEV = Hybrid electric vehicle; PHEV = Plug-in hybrid electric vehicle; BEV = Battery electric vehicleTable 3: Example traction inverters used in automobiles (as reported in John Reimers et al. Automotive Traction Inverters: Current Status and Future Trends. IEEE Transactions on Vehicular Technology, 2019, DOI: 10.1109 / TVT.2019.2897899).FURTHER EXAMPLE EMBODIMENTS

[0119] Table 2 provides a non-limiting list of example traction inverters and automotive traction inverters that are commercially available as at November 2023. It is to be understood that the listing in Table 2 is purely illustrative and not exhaustive. Other traction inverters that are not listed in Table 2 may fall within the scope of the invention.

[0120] Table 3 provides a non-limiting list of traction inverters used in electric and electric -hybrid automobiles. It is to be understood that the listing in Table 3 is purely illustrative and not exhaustive. Other automotive traction inverters that are not listed in Table 3 may fall within the scope of the invention.

[0121] Figure 1 provides a schematic of an example embodiment. An industrial electrolyser 100 incorporates a traction inverter 110 (within its balance-of-plant), which is connected to a cell stack 111 within the industrial electrolyser 100. When operated in reverse, electrical energy in the form of AC power passes along the external cable or bus connection 101 to the AC side (110-AC) of the traction inverter 110, then through the traction inverter 110, which converts the AC power to DC power that exits at the DC side (110-DC) of the traction inverter 110. The DC side (110-DC) of the traction inverter 110 is connected to the DC cable or bus 102, which is, in turn, connected to the cell stack 111 of the industrial electrolyser 100.

[0122] It is to be understood that the traction inverter 110 may be any traction inverter, including any traction inverter described herein, or any other traction inverter that falls within the definition of a traction inverter provided here.

[0123] The traction inverter 110 may, for example, be a traction inverter designed for use in automobiles (electric vehicles), for example of the type manufactured by Eaton Corporation, of 1000 Eaton Blvd, Beachwood, OH 44122, USA, which is listed in Table 2. Pages 24 to 27 of the Eaton eMobility brochure (Eaton_eMobility_Interactive Brochure_2-9-23_V9.4 pro_SPFSV.pdf, and downloadable from https: / / www.eaton.com / content / dam / eaton / products / emobilitv / eaton-emobilitv-guide-brochure-emobOOO 1 -en.pdf , dated 15 Feb 2023), as well as the website at https: / / www.eaton.com / us / en-us / catalog / emobility / high-voltage-inverter.html provide technical details of this traction inverter. It has a peak energy efficiency of between 95- 98%, depending on whether IGBT or SiC power electronic switches are used, a power rating of 80-250 kW at peak load, with maximum output voltage of 800 V and current of 300-800 A. The Eaton traction inverter is also liquid cooled. The manufacturer outlines that the liquid coolant should be maintained at a temperature of up to 70 °C, with a flow rate of 10 litres per minute. The traction inverter has a power density of 35 kW / L.

[0124] As depicted in Figure 1, the traction inverter 110 incorporates a liquid cooling circuit 120, wherein a liquid coolant 121 flows in the direction shown by the arrows (at 121). The liquid coolant circuit 120 passes through a cooling unit 125, which maintains the temperature of the liquid coolant 121. As noted above, the maximum coolant temperature of the liquid coolant 121 in cooling circuit 120, during operation of the traction inverter 100, is 70 °C; this is greater than or equal to 60 °C, greater than or equal to 59 °C, greater than or equal to 58 °C, greater than or equal to 57 °C, greater than or equal to 56 °C, greater than or equal to 55 °C, greater than or equal to 54 °C, greater than or equal to 53 °C, greater than or equal to 52 °C, greater than or equal to 51 °C, or greater than or equal to 50 °C. The cooling unit 125 may be, for example, a liquid chiller.

[0125] It is to be understood that the industrial electrolyser 100 and cell stack 111 may be an industrial electrolyser and cell stack of any type, including an alkaline, PEM, solid oxide, or any other type of electrolyser and associated cell stack.

[0126] The industrial electrolyser 100 may be an alkaline electrolyser of the type described in International Patent Publication Nos. W02022056603, W02022056604, W02022056605, and W02022056606, and produced by the company Hysata Pty Ltd, of 1 Darcy Road, Port Kembla, NSW 2505, Australia. The electrolyser may contain a cell stack 111. The cell stack 111 may be designed and configured to require an input voltage of 755-775 V and a current of 280 A during operation (over the lifetime of the electrolyser). These values may be chosen to substantially match the Eaton traction inverter described above, as they fall a little below the maximum output voltage of 800 V and current of 300A of the Eaton traction inverter. That is, the industrial electrolyser cell stack 111 may be designed to operate near to, but not exceed the maximum for the traction inverter 100. In this way, the industrial electrolyser cell stack 111 may be configured to require voltage and current ranges that are substantially similar to those produced by the traction inverter 110.

[0127] This may be achieved by incorporating 500 individual cells into the cell stack 111, wherein each cell is designed and configured to require 1.51 - 1.55 V during operation (over the lifetime of the electrolyser). Each cell may, moreover, be configured to utilize electrodes of 400 cm2area, meaning that, during operation, at a fixed current density (over the lifetime of the electrolyser) of 0.700 A / cm2, each cell requires a current of 280 A to pass through it. As each cell in the cell stack 111 may be connected in electrical series to the next cell in the cell stack 111, the cell stack 111 may thereby require a current of 280 A to pass through it during operation of the industrial electrolyser 110. Moreover, as industrial electrolysers 100 of the type described in International Patent Publication Nos. W02022056603, W02022056604, W02022056605, and W02022056606, avoid ‘shunt’ currents (also called ‘bypass’ currents) in the cell stack 111, the total power required by the industrial electrolyser cell stack 111 during operation (over the lifetime of the electrolyser) may be, accordingly, 211 - 217 kW, this being a simple function of the required voltage and current ranges.

[0128] In this way, the individual cells, the individual electrodes, and their configuration in the cell stack 111 of the industrial electrolyser 100 may be configured to require voltages, currents, and power input ranges that are substantially similar to those of the traction inverter 110. This may involve configuring: the size of the electrodes in the cell stack / s to provide for the desired range of currents; the number of cells in the cell stack / s to provide for the desired range of voltages; and optimizing the size of the electrodes, the number of cells, and their configuration in the cell stack / s to avoid the incidence and effect of ‘shunt’ currents (also called ‘bypass’ currents) to thereby provide for a particular range of power inputs.

[0129] Most alkaline electrolyser cell stacks allow the presence of shunt currents. Clearly defined and narrow power ranges of the type described above (over the lifetime ofthe electrolyser) are far more difficult to achieve with an electrolyser cell stack that allows for the presence of shunt currents. This is because shunt currents may, by their nature, be unpredictable and ‘self-amplifying’; that is, they may unexpectedly change their patterns within the cell stack and significantly increase in intensity over time, especially but not only if they produce new corrosion mechanisms and pathways within the cell stack. Avoidance of shunt currents therefore notably simplifies the process of matching the voltage, current, and power requirements of a cell stack 111 (over the lifetime of the electrolyser 100) to the outputs of a traction inverter 110, operating in reverse.

[0130] The temperature of the cell stack 111 during operation of the industrial electrolyser 100 may be 75-90 °C. The cell stack 111 may be liquid cooled and incorporated a liquid cooling circuit 130, within which a liquid coolant 131 flowed (in the direction of the arrows at 131). The liquid cooling circuit may flow through a cooling unit 135 that manages the temperature of liquid coolant 131 in the liquid cooling circuit 130. When operated at 75 °C, the liquid coolant 131 may be maintained at a temperature of 70 °C. The cooling unit 135 may be, for example, a liquid chiller.

[0131] In one embodiment (shown in Figure 1), the traction inverter 110, operating in reverse (i.e. passing power from the AC side to the DC side), may power the cell stack 111, wherein the traction inverter 110 and the cell stack 111 may have two separate liquid cooling systems, namely cooling system 120 for the traction inverter 110, and cooling system 130 for the cell stack 111, with the temperature of the liquid coolant 121 in the traction inverter 110 during operation being up to 70 °C, and the temperature of the liquid coolant 131 in the cell stack 111 (operating at, for example, 90 °C) being 85 °C.

[0132] In another example embodiment, during operation, the coolant temperature within the cell stack 111 may be similar or identical to the coolant temperature within the traction inverter 110, for example 70 °C. Figure 2 schematically depicts such a case. An industrial electrolyser 200 may contain a traction inverter 110, operating in reverse, wherein the traction inverter 110 and the cell stack 111 have a common, shared liquid cooling system 140 with the maximum coolant temperature of the liquid coolant 141 being 70 °C. That is, a liquid coolant of the liquid cooling system 140 may be in fluidcommunication with both the traction inverter 110 and the cell stack 111. Externally supplied AC power may pass via AC cable or bus 101 into the AC side (110- AC) of the traction inverter 110, which operates in reverse. The traction inverter 110 may output DC electrical power at its DC side (110-DC), which is connected to a DC cable or bus 102, and thereby to the cell stack 111. The liquid coolant 141 may flow around the shared, common liquid coolant loop 140 through a cooling unit 145, which maintains the temperature of the liquid coolant 141 during operation. The cooling unit 145 may be, for example, a liquid chiller.

[0133] Given that the traction inverter referred to above may have a power density of 35 kW / L, its use within the balance-of-plant may notably decrease the footprint of the full industrial electrolyser system 100 or 200.

[0134] In order to power the cell stack 111 and the full industrial electrolyser system 100 or 200, the control system of the traction inverter 110 may have to be adapted or replaced. Several adaptations or replacements could be made in this respect. For example, the control card on the traction inverter 110 may be replaced with a control card that allows only for reverse operation.

[0135] The interfacing hardware of the traction inverter may also need to be adapted or replaced to allow the traction inverter 110 to power the full industrial electrolyser system 100 or 200. For example, a DC-DC converter may need to be introduced.

[0136] In one example embodiment, a pre-charge circuit of the traction inverter may be replaced or adapted to power the industrial electrolyser. Because electrical energy is normally introduced from the DC side, traction inverters may employ a capacitor to filter the voltage of the DC bus, with a pre-charge circuit to pre-charge the capacitor. To avoid current spikes deriving from a large in-rush current, a circuit with a resistor or active switches may also be utilised. While necessary for operation in the forward direction, these components may not be needed when the traction inverter operates solely in the reverse direction, as would be needed to power an attached industrial electrolyser. Accordingly,such interfacing hardware may be removed from the traction inverter and replaced with a pre-charge circuit on the AC side of the traction inverter. Preferably, the pre-charge circuit is replaced to charge up the industrial electrolyser load voltage to a capacitor voltage in the traction inverter to prevent a large in-rush current at start-up. Alternatively, such interfacing hardware may be retained and adapted to become a ‘soft-switching circuit’ for the load on the DC side of the traction inverter when it operates in the reverse direction. Inductors may also be added on the input side, for example, to allow voltage boost functionality.

[0137] In some embodiments, both the control system and the interfacing hardware of the traction inverter may be adapted or replaced to allow the traction inverter to provide power to operate the industrial electrolyser. Preferably but not exclusively, the control system of the traction inverter is adapted or replaced to power the industrial electrolyser, and the interfacing hardware of the traction inverter is adapted or replaced to enable connection to the electrolyser; and wherein the pre-charge circuit of the traction inverter is adapted or replaced to power the industrial electrolyser.

[0138] In a still further aspect, there is provided a traction inverter wherein the control system is replaced with a control system that can detect incoming three-phase voltage waveforms and convert them into a controllable DC output. This may require extra sensors on the AC side, for example voltage sensors. The sensors may be needed to facilitate an algorithm that determines the phase angle and frequency of the incoming waveforms. One example of such an algorithm is a ‘phase lock loop’ (FLL) in this respect.

[0139] By means such as those described above, a traction inverter 110, operated in reverse, can be used to power an industrial electrolyser 100 or 200, to thereby increase the comparative, overall energy efficiency and lower the overall cost of the full industrial electrolyser system 100 or 200.

[0140] Figure 3 schematically depicts the above method 300 of use of an embodiment of the invention. At step 310, the individual cells and their electrodes are configured in a cell stack of the industrial electrolyser to require voltages, currents, and power input ranges that are substantially similar to those of the traction inverter. This mayinvolve configuring: the size of the electrodes in the cell stack / s to provide for a particular range of currents; the number of cells electrodes in the cell stack / s to provide for a particular range of voltages; and / or optimizing the cell stack / s to avoid or minimise the incidence or effect of ‘shunt’ currents (also called ‘bypass’ currents) to provide for a particular range of power inputs. At step 320, the control system and / or the interface hardware and / or other components of the traction inverter are adapted or replaced. For example, the control system may be changed to enable constant reverse operation of the traction inverter. In another example, the interface hardware of the traction inverter may be changed. In a further example, a new control system or interface may be retrofitted; connecting the traction inverter to the industrial electrolyser. At step 330, an electrical current is passed from the traction inverter into the industrial electrolyser.

[0141] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms, in keeping with the broad principles and the spirit of the invention described herein.

[0142] The present invention and the described preferred embodiments specifically include at least one feature that is industrial applicable.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A system for supplying electrical power to an electro-synthetic cell, the system comprising: an electro-synthetic cell; and, a traction inverter electrically connected to the electro-synthetic cell, the traction inverter comprising: a control system, wherein the control system is configured to operate the traction inverter in reverse such that an alternating current (AC) input to the traction inverter is converted into a direct current (DC) output from the traction inverter to power the electro-synthetic cell.

2. The system of claim 1, wherein the electro-synthetic cell is an industrial electrolyser.

3. The system of claim 1 or 2, wherein the traction inverter is an automotive traction inverter.

4. The system of any one of claims 1 to 3, wherein the traction inverter comprises a liquid cooling system with a coolant.

5. The system of claim 4, wherein the liquid cooling system and the coolant are common to both the traction inverter and the electro-synthetic cell, or wherein the coolant is in fluid communication with the traction inverter and the electro-synthetic cell.

6. The system of claim 4 or claim 5, wherein, during operation, the coolant has a maximum coolant temperature of greater than or equal to 50 °C.

7. The system of claim 4 or claim 5, wherein, during operation, the coolant has a maximum coolant temperature of greater than or equal to 60 °C.

8. The system of any one of claims 1 to 7, wherein, during operation, the system has a power density greater than or equal to 5 kW / litre.

9. The system of any one of claims 1 to 7, wherein, during operation, the system has a power density greater than or equal to 18 kW / litre.

10. The system of any one of claims 1 to 9, wherein, during operation, the system has a specific power greater than or equal to 5 kW / kg.

11. The system of any one of claims 1 to 9, wherein, during operation, the system has a specific power greater than or equal to 18 kW / kg.

12. The system of any one of claims 1 to 11, wherein the control system is adapted from an original configuration to operate the traction inverter in reverse to power the electro-synthetic cell.

13. The system of any one of claims 1 to 11, wherein the control system is replaced with a replacement control system having an alternative configuration to operate the traction inverter in reverse to power the electro-synthetic cell.

14. The system of any one of claims 1 to 13, further comprising an interfacing hardware.

15. The system of claim 14, wherein the interfacing hardware is adapted from an original configuration to enable connection to the electro-synthetic cell, or wherein the interfacing hardware is replaced by a replacement interfacing hardware having an alternative configuration to enable connection to the electro-synthetic cell.

16. The system of any one of claims 1 to 15, further comprising a pre-charge circuit to provide power to the electro-synthetic cell.

17. The system of claim 16, wherein the pre-charge circuit is adapted from an original configuration to provide power to the electro-synthetic cell, or wherein the pre-charge circuit is replaced by a replacement pre-charge circuit having an alternative configuration to provide power to the electro-synthetic cell.

18. The system of claim 14 or claim 16 wherein the control system of the traction inverter is adapted or replaced to operate the traction inverter in reverse to power the electro-synthetic cell, and wherein the interfacing hardware of the traction inverter is adapted or replaced to enable connection to the electro-synthetic cell; and wherein the precharge circuit of the traction inverter is adapted or replaced to power the electro-synthetic cell,19. The system of any one of claims 1 to 18, wherein the control system is adapted to detect if the alternating current (AC) input to the traction inverter has three-phase voltage waveforms and if so to convert the three-phase voltage waveforms into the direct current (DC) output from the traction inverter.

20. The system of claim 16 or claim 17, wherein the pre-charge circuit charges up a load voltage of the electro-synthetic cell to a DC bus capacitor voltage in the traction inverter to prevent a large in-rush current at start-up of the system.

21. A traction inverter electrically connected to an electro-synthetic cell, the traction inverter comprising: a control system, wherein the control system is configured to operate the traction inverter in reverse such that alternating current (AC) input to the traction inverter is converted into direct current (DC) output from the traction inverter to power the electrosynthetic cell.

22. A traction inverter used in the system of any one of claims 1 to 20.

23. A traction inverter connected to an industrial electrolyser, the traction inverter comprising: a control system, wherein the control system is configured to operate in reverse such that alternating current (AC) is converted into direct current (DC) to power the industrial electrolyser, wherein the traction inverter comprises a liquid cooling system, wherein the maximum coolant temperature is greater than or equal to 50 °C, wherein the power density of the traction inverter is greater than or equal to 5 kW / litre, wherein the traction inverter has a specific power greater than or equal to 5 kW / kg, wherein the control system of the traction inverter is adapted or replaced to operate the traction inverter in reverse to power the industrial electrolyser, wherein the interfacing hardware of the traction inverter is adapted or replaced to enable connection to the electrolyser, and / or wherein the pre-charge circuit of the traction inverter is adapted or replaced to power the industrial electrolyser.

24. The traction inverter of claim 23, wherein the maximum coolant temperature is greater than or equal to 60 °C.

25. A traction inverter connected to an industrial electrolyser, the traction inverter comprising: a control system, wherein the control system is configured to operate in reverse such that alternating current (AC) is converted into direct current (DC) to power the industrial electrolyser, wherein the traction inverter comprises a liquid cooling system, wherein the maximum coolant temperature is greater than or equal to 60 °C, wherein the power density of the traction inverter is greater than or equal to 18 kW / litre, wherein the traction inverter has a specific power greater than or equal to 18 kW / kg, wherein the control system of the traction inverter is adapted or replaced to operate the traction inverter in reverse to power the industrial electrolyser,wherein the interfacing hardware of the traction inverter is adapted or replaced to enable connection to the electrolyser; wherein the pre-charge circuit of the traction inverter is adapted or replaced to power the industrial electrolyser, wherein the control system is replaced with a control system to detect incoming three-phase voltage waveforms and convert them into a controllable DC output, and / or wherein the pre-charge circuit is replaced to charge up the industrial electrolyser load voltage to the DC bus capacitor voltage in the traction inverter to prevent a large inrush current at start-up.

26. A method for powering an electro-synthetic cell, the electro-synthetic cell comprising: at least one electrode requiring a supply of direct current (DC) for operation of the electro-synthetic cell; a traction inverter electrically connected to the electro-synthetic cell, the method comprising: operating the traction inverter in reverse such that alternating current (AC) input to the traction inverter is converted into direct current (DC) output from the traction inverter and supplied to the at least one electrode.

27. The method of claim 26, wherein the electro- synthetic cell is an industrial electrolyser.

28. The method of claim 26 or claim 27, wherein the traction inverter comprises a control system, and the control system is configured to operate the traction inverter in reverse.

29. The method of any one of claims 26 to 28, comprising configuring the electrosynthetic cell and / or the at least one electrode to require a voltage, and / or a current, and / or a power input range that are substantially similar to a voltage, and / or a current and / or a power output range of the traction inverter.

30. The method of any one of claims 26 to 29, wherein the traction inverter is an automotive traction inverter.

31. The method of any one of claims 26 to 30, further comprising multiple electrosynthetic cells provided in one or more cell stacks.

32. The method of claim 29, wherein configuring the at least one electrode involves configuring a size of the at least one electrode to provide for a selected range of currents.

33. The method of claim 31, wherein configuring an individual cell of the multiple electro-synthetic cells comprises: configuring a number of the individual cells in the one or more cell stacks to provide for a selected range of voltages.

34. The method of claim 31, wherein configuring an individual cell of the multiple electro-synthetic cells comprises: optimizing the one or more cell stack to avoid or minimise the incidence or effect of shunt or bypass currents to provide for a selected range of power inputs.

35. The method of claim 28, wherein the control system enables constant reverse operation of the traction inverter.

36. The method of claim 28 or claim 35, including: detecting, by the control system, if the alternating current (AC) input to the traction inverter has three-phase voltage waveforms and if so converting the three-phase voltage waveforms into the direct current (DC) output from the traction inverter.

37. The method of any one of claims 26 to 36, including a pre-charge circuit to: charge up a load voltage of the electro- synthetic cell to a DC bus capacitor voltage in the traction inverter to prevent a large in-rush current at start-up of the electro-synthetic cell.

38. The system, the traction inverter, or the method of any one of claims 1 to 37, wherein the traction inverter has a power output of greater than or equal to 50 kW.

39. The system, the traction inverter, or the method of any one of claims 1 to 38, wherein the traction inverter has been intended to or designed to propel a non-stationery moving vehicle.

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