System and method for electric vehicle operation

Abstract

A power management system 200 for an electric vehicle (EV) comprises a power distribution module 202 couplable to a plurality of power sources of the EV, specifically: a hydrogen fuel cell (208-Fig.4A

Description

Field

[001] Embodiments of the present techniques generally relate to a power management system and an electric vehicle. In particular, the present application relates to a power management system for activating a hydrogen fuel cell of an electric vehicle when a high-capacity power source is depleted below a predetermined threshold, and an electric vehicle comprising such a power management system. Background

[002] Electric vehicles, EV’s, powered by hydrogen fuel cells are show great promise for tackling the carbon emissions of the automotive industry. Typically, hydrogen fuel cell electric vehicles comprise multiple power sources, each tailored to performing different tasks. The effective management of these power sources is crucial for ensuring the effective operation of fuel cell EV’s.

[003] Idling is a particular problem for fuel cell vehicles, and may occur as a result of sub-optimal power management. In particular, fuel cells rely on recirculation blowers to ensure the circulation of air and hydrogen within the vehicle. Typically, these blowers are activated by an ultracapacitor, or another similar high-capacity power source. However, there are cases where this power source is depleted to such an extent that there is insufficient charge to activate the fuel cell. This can result in the electric vehicle idling until, for example, an external power source is connected to the fuel cell for its activation. Current techniques commonly tackle this problem by including additional power sources on board the vehicle. However, such high-capacity power sources are generally heavy, and reduce the payload of the vehicle. This problem is particularly acute for electric vehicles such as delivery vans, where maximising the payload of the vehicle is critical for economic efficiency.

[004] The present applicant has identified the need for an improved power management system in electric vehicles. Summary

[005] In a first approach of the present techniques, there is provided a power management system for an electric vehicle, the power management system comprising: a power distribution module couplable to: a plurality of power sources of the electric vehicle, the plurality of power sources comprising: a hydrogen fuel cell comprising an anode and a cathode; a vehicle battery; and a high-capacity power source; an anode blower of the electric vehicle, wherein the anode blower is for activating the anode of the hydrogen fuel cell when a voltage applied to the anode blower is greater than an anode threshold voltage; and a cathode blower of the electric vehicle, wherein the cathode blower is for activating the cathode of the hydrogen fuel cell when a voltage applied to the cathode blower is greater than a cathode threshold voltage; a voltage conversion module coupled to the power distribution module; and at least one processor coupled to memory and configured to: determine whether the high-capacity power source is depleted below a predetermined threshold charge; and when it is determined that the high-capacity power source is below the predetermined threshold charge: control the voltage conversion module to convert a voltage supplied by the battery to generate a converted voltage having a value greater than the anode and cathode threshold voltages; and control the power distribution module to direct the converted voltage to the anode blower and the cathode blower, thereby applying the converted voltage to the blowers for activating the hydrogen fuel cell.

[006] The term “power distribution module” used herein means a device with multiple outlets / terminals designed to distribute electrical power to multiple components by coupling the components to the outlets / terminals. For example, the power distribution module may be a power distribution unit (PDU) or a high-voltage PDU (HV-PDll) designed for use and coupling to components of an electric vehicle.

[007] Advantageously, the present techniques provide an effective way of activating an EV with minimal additional hardware and which therefore minimises vehicle payload reduction. EVs can suffer from idling when the high-capacity power source is depleted below a predetermined threshold required to activate the fuel cell. Current techniques typically tackle this problem by including additional high-capacity power sources onboard the vehicle. However, such power sources are typically heavy, and reduce the payload of the vehicle. This is particularly important for vehicles in the haulage industry, such as electric delivery vans and lorries, where payload maximisation is crucial. The present techniques provide an alternative way of tackling this problem by utilising a voltage conversion module and the vehicle battery (e.g. the 12V vehicle battery), i.e. without an additional high-capacity power source. The battery of the vehicle may be used as an alternative or “back-up” power source to activate the fuel cell, thereby minimising the amount of time that the EV is in an idle state. Vehicle batteries conventionally have a voltage of approximately 12V. However, this voltage is typically below the threshold voltage(s) required to activate the anode and cathode blowers used to respectively activate the anode and cathode of the hydrogen fuel cell. The present techniques employ a voltage conversion module coupled to the battery to generate a converted voltage whose value is greater than the anode and cathode threshold voltages for activating the fuel cell via the anode and cathode blowers. That is, the present techniques provide a robust and dependable way of leveraging the multiple power sources of an EV, thereby ensuring that the fuel cell may be activated in circumstances where the high-capacity power source typically used to activate the fuel cell is substantially depleted.

[008] After activating the fuel cell, the present techniques advantageously provide a way of charging the vehicle battery and the high-capacity power source. That is, once the “back-up” power source of the vehicle battery is used to activate the fuel cell, the charge of the vehicle battery may be restored. This is advantageous because charge may be restored to the vehicle battery and to resume “normal” operation of the EV. In other words, the at least one processor may be further configured to control the power distribution module to direct power from the hydrogen fuel cell to the vehicle battery to thereby charge the vehicle battery, once the hydrogen fuel cell is activated.

[009] The voltage conversion module may be a bi-directional voltage conversion module. That is, the voltage conversion module may be configured to both increase and decrease voltages, in different modes of operation. This advantageously ensures the flexibility of the present techniques for directing power to different components, depending on whether or not the hydrogen fuel cell is activated.

[010] In particular, the bi-directional voltage conversion module may be configured to generate the converted voltage in a first mode of operation for increasing voltage. In this case, the at least one processor may be configured to control the bi-directional voltage conversion module to generate the converted voltage by setting the bi-directional voltage conversion module to the first mode of operation. That is, the first mode of operation may be understood as a first “direction” whereby the voltage of the vehicle battery is increased for activating the blowers of the fuel cell.

[011] Accordingly, the bi-directional voltage conversion module may be further configured to generate a down converted voltage in a second mode of operation for decreasing voltages. In this case, the at least one processor may be further configured to: when it is determined that the high-capacity power source is above the predetermined threshold: control the power distribution module to direct power from the high-capacity power source to the anode blower and the cathode blower for activating the hydrogen fuel cell; and control the bi-directional voltage conversion module to generate the down converted voltage, using the second mode of operation, for re-charging the vehicle battery whilst the hydrogen fuel cell is activated using power supplied to the bi-directional voltage conversion module by the power distribution module. The at least one processor may be configured to control the bi-directional voltage conversion module to generate the converted voltage by setting the bi-directional voltage conversion module to the second mode of operation. That is, the second mode of operation may be understood as a second “direction” whereby voltages are decreased for (re-)charging the vehicle battery whilst the hydrogen fuel cell is active. The second mode of operation may be considered a “conventional” mode of operation, in line with how EV’s conventionally operate to charge the vehicle battery whilst the EV is running. In this case, power is supplied to the bi-directional voltage conversion module by the power distribution module. As noted above, multiple high-voltage power sources are couplable to the power distribution module, such as the high-capacity power source. In essence, the second mode of operation described above amounts to the supply of power to the bi-directional voltage conversion module by these high-voltage power sources via the power distribution module, and a down conversion of this power for re-charging the vehicle battery.

[012] The high-capacity power source may be a high-capacity battery. Alternatively, the high-capacity power source may be an ultracapacitor (or, equivalently, a supercapacitor). In both cases, the high-capacity power source is capable of activating both the anode and cathode of the hydrogen fuel cell. Furthermore, it will be appreciated that the high-capacity power source may be any power source capable of activating the anode and cathode mentioned above.

[013] In cases where the high-capacity power source is a high-capacity battery, the high-capacity battery may comprise a battery array formed of a plurality of batteries, and the power management system may further comprise a plurality of integrated circuits, wherein each integrated circuit is coupled to a battery of the battery array for controlling power discharge from each of the batteries of the battery array. That is, the high-capacity battery array may comprise multiple batteries, each with a corresponding integrated circuit for precisely controlling discharge from each of the batteries. In this case, the at least one processor may be configured to determine whether the high-capacity power source is depleted below the predetermined threshold by determining, using the plurality of integrated circuits, whether a total charge amount aggregated over all of the plurality of batteries is below the predetermined threshold.

[014] In cases where the high-capacity power source is an ultracapacitor, the ultracapacitor may comprise a capacitor array comprising a plurality of capacitors and the power management system may further comprise a plurality of integrated circuits, wherein each integrated circuit is coupled to a capacitor of the capacitor array for controlling power discharge from each of the capacitors of the capacitor array. That is, in a similar way to the example of the high-capacity battery above, the ultracapacitor may comprise multiple capacitors, each with a corresponding integrated circuit for precisely controlling discharge from each of the capacitors. It will be appreciated that each of the capacitors may themselves be considered as capacitors suitable for use in EV’s (i.e. ultracapacitors), as opposed to electrolytic capacitors that are e.g. used as components in printed circuit boards. Typically, the capacitance of the ultracapacitors is in the region of 100 F to 25,000 F, more preferably in the range of 20 F to 22,000 F. In this case, the at least one processor may be configured to determine whether the high-capacity power source is depleted below the predetermined threshold by determining, using the plurality of integrated circuits, whether a total charge amount aggregated over all of the plurality of capacitors is below the predetermined threshold.

[015] As noted above, once the hydrogen fuel cell is activated, the present techniques may direct power from the hydrogen fuel cell to the vehicle battery for charging the vehicle battery. Similarly, it is important that charge is restored to the high-capacity power source for resuming standard operation of the EV. That is, the at least one processor may be further configured to control the power distribution module to direct power from the hydrogen fuel cell to the high-capacity power source for charging the high-capacity power source, once the hydrogen fuel cell is activated.

[016] The power management system may further comprise a first cooling system for cooling the voltage conversion module. The first cooling system may be or may comprise a water pump. That is, the first cooling system ensures the dissipation of heat generated by operation of the voltage conversion module during its operation.

[017] The operational voltage of the hydrogen fuel cell is normally determined by the characteristics of the fuel cell. There is typically a discrepancy between the operational voltage of the fuel cell and that required by the power distribution. Thus, the power distribution may be coupled to the hydrogen fuel cell by a unidirectional voltage conversion module. The power management system may further comprise a second cooling system for cooling the unidirectional voltage conversion module. In a similar way to the first cooling system above, the second cooling system may be or may comprise a water pump.

[018] The voltage conversion module may be a bi-directional DC-to-DC converter. That is, the voltage conversion module may be capable of converting DC signals to DC signals with a higher or lower voltage.

[019] In a second approach of the present techniques, there is provided an electric vehicle comprising: a plurality of power sources comprising: a hydrogen fuel cell comprising an anode and a cathode; a vehicle battery; and a high-capacity power source; an anode blower for activating the anode of the hydrogen fuel cell when a voltage applied to the anode blower is greater than an anode threshold voltage; a cathode blower for activating the cathode of the hydrogen fuel cell when a voltage applied to the cathode blower is greater than a cathode threshold voltage; and the power management system as described above in relation to the first aspect for activating the hydrogen fuel cell. That is, in addition to providing a power management system that may be retro-fitted to existing EV’s, the present techniques also provide an EV comprising the power management system described above. The features described above in relation to the first aspect apply equally to the power management system of the second aspect, and are not repeated for the sake of conciseness.

[020] In a third approach of the present techniques, there is provided a method for operating an electric vehicle, the electric vehicle comprising a plurality of power sources including a hydrogen fuel cell, a vehicle battery and a high-capacity power source, the method comprising: determining whether the high-capacity power source is depleted below a predetermined threshold charge; and when it is determined that the high-capacity power source is below the predetermined threshold charge: controlling a voltage conversion module of the electric vehicle to convert a voltage supplied by the vehicle battery to generate a converted voltage having a value greater than anode and cathode threshold voltages of, respectively, an anode blower of the electric vehicle and a cathode blower of the electric vehicle, wherein the anode blower activates an anode of the hydrogen fuel cell when a voltage applied to the anode blower is greater than the anode threshold voltage and wherein the cathode blower activates a cathode of the hydrogen fuel cell when a voltage applied to the cathode blower is greater than the cathode threshold voltage; and controlling a power distribution module of the electric vehicle to direct the converted voltage to the anode blower and the cathode blower to activate the hydrogen fuel cell.

[021] The method may further comprise controlling the power distribution module to direct power from the hydrogen fuel cell to the vehicle battery for charging the vehicle battery, once the fuel cell is activated.

[022] In a related approach of the present techniques, there is provided a computer-readable storage medium comprising instructions which, when executed by a processor, causes the processor to carry out any of the methods described herein.

[023] As will be appreciated by one skilled in the art, the present techniques may be embodied as a system, method or computer program product. Accordingly, present techniques may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects.

[024] Furthermore, the present techniques may take the form of a computer program product embodied in a computer readable medium having computer readable program code embodied thereon. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may be, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

[025] Computer program code for carrying out operations of the present techniques may be written in any combination of one or more programming languages, including object oriented programming languages and conventional procedural programming languages. Code components may be embodied as procedures, methods or the like, and may comprise subcomponents which may take the form of instructions or sequences of instructions at any of the levels of abstraction, from the direct machine instructions of a native instruction set to high-level compiled or interpreted language constructs.

[026] Embodiments of the present techniques also provide a non-transitory data carrier carrying code which, when implemented on a processor, causes the processor to carry out any of the methods described herein.

[027] The techniques further provide processor control code to implement the abovedescribed methods, for example on a general purpose computer system or on a digital signal processor (DSP). The techniques also provide a carrier carrying processor control code to, when running, implement any of the above methods, in particular on a non-transitory data carrier. The code may be provided on a carrier such as a disk, a microprocessor, CD- or DVD- ROM, programmed memory such as non-volatile memory (e.g. Flash) or read-only memory (firmware), or on a data carrier such as an optical or electrical signal carrier. Code (and / or data) to implement embodiments of the techniques described herein may comprise source, object or executable code in a conventional programming language (interpreted or compiled) such as Python, C, or assembly code, code for setting up or controlling an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array), or code for a hardware description language such as Verilog (RTM) or VHDL (Very high speed integrated circuit Hardware Description Language). As the skilled person will appreciate, such code and / or data may be distributed between a plurality of coupled components in communication with one another. The techniques may comprise a controller which includes a microprocessor, working memory and program memory coupled to one or more of the components of the system.

[028] It will also be clear to one of skill in the art that all or part of a logical method according to embodiments of the present techniques may suitably be embodied in a logic apparatus comprising logic elements to perform the steps of the above-described methods, and that such logic elements may comprise components such as logic gates in, for example a programmable logic array or application-specific integrated circuit. Such a logic arrangement may further be embodied in enabling elements for temporarily or permanently establishing logic structures in such an array or circuit using, for example, a virtual hardware descriptor language, which may be stored and transmitted using fixed or transmittable carrier media.

[029] In an embodiment, the present techniques may be realised in the form of a data carrier having functional data thereon, said functional data comprising functional computer data structures to, when loaded into a computer system or network and operated upon thereby, enable said computer system to perform all the steps of the above-described method. Brief description of the drawings

[030] Implementations of the present techniques will now be described, by way of example only, with reference to the accompanying drawings, in which:

[031] Figure 1 is a schematic diagram showing how power is managed in an electric vehicle comprising a hydrogen fuel cell;

[032] Figure 2 is a schematic diagram of a power management system for an electric vehicle;

[033] Figure 3A is a schematic diagram showing more details of the power distribution module of Figure 2;

[034] Figure 3B is a block diagram which schematically illustrates a power distribution module coupled to a plurality of power sources;

[035] Figure 4A is a schematic diagram illustrating more details of the hydrogen fuel cell of Figure 3B;

[036] Figure 4B is a schematic diagram illustrating more details of the high-capacity power sources of Figure 3B;

[037] Figure 5A is a schematic diagram showing more details of the voltage conversion module of Figure 2;

[038] Figure 5B is a schematic diagram showing a unidirectional voltage conversion module;

[039] Figure 6 is a block diagram of an electric vehicle comprising a power management system; and

[040] Figure 7 is a flowchart of example steps in a method for operating an electric vehicle. Detailed description of the drawings

[041] Broadly speaking, the present techniques generally relate to a power management system and an electric vehicle. In particular, the present application relates to a power management system for activating a hydrogen fuel cell of an electric vehicle when a high-capacity power source is depleted below a predetermined threshold, and an electric vehicle comprising such a power management system.

[042] Figure 1 is a schematic diagram showing how power is managed in an electric vehicle comprising a hydrogen fuel cell. Hydrogen fuel cell electric vehicles (FCEVs) 100 have potential to play a key role in the efforts of the automotive industry to reduce carbon emissions. FCEVs 100 produce electricity using a fuel cell 102 powered by hydrogen, rather than drawing electricity from only a vehicle battery. Anode and cathode blowers (not shown in Figure 1) are crucial components of FCEV’s 100. The anode blower ensures the circulation of hydrogen along a path from hydrogen fuel tanks to the anode of the fuel cell 102, whilst the cathode blower ensures the circulation of air from the environment of the FCEV to the cathode of the fuel cell. The continuous circulation of hydrogen and air within the FCEV to the electrodes of the fuel cell ensures that the redox reactions occurring within the fuel cell are sustained, ensuring the supply of electricity for powering the FCEV. A power distribution module 104 controls the distribution of power within the FCEV, for example, by directing power from the fuel cell to an electric drive axle.

[043] Conventionally, a high-capacity power source 106, such as a high-capacity battery or an ultracapacitor, is used to activate the anode and cathode blowers by applying a voltage to the blowers. However, when the high-capacity power source 106 is depleted below a predetermined threshold (i.e. entirely depleted or partially depleted), then the charge remaining in the high-capacity power source 106 is insufficient to activate the blowers. This can result in the FCEV being idle until e.g. an external or an additional power supply is connected to the vehicle for activating the blowers. The present applicant has therefore identified the need for an improved power management system in electric vehicles for activating the anode and cathodes of a hydrogen fuel cell.

[044] Figure 2 is a schematic diagram of a power management system for an electric vehicle. The power management system 200 comprises a power distribution module 202, a voltage conversion module 204 coupled to the power distribution module 204 and at least one processor 206 coupled to memory. The power management system is configured to activate the anodes and cathodes of a hydrogen fuel cell in circumstances where the high-capacity power source typically used for activation of the electrodes has insufficient charge.

[045] Figure 3A is a schematic diagram showing more details of the power distribution module of Figure 2. As noted above, the power distribution module 202 may comprise a plurality of outlets / terminals 202-1, 202-2, ... , 202-N designed to distribute electrical power to multiple components by coupling the components to the outlets / terminals 202-1, 202-2, ... , 202-N. For example, the power distribution module may be a power distribution unit (PDU) or a high-voltage PDU (HV-PDll) designed for use with, and coupling to, components of an electric vehicle.

[046] In particular, the power distribution module 202 is couplable to a plurality of power sources of the electric vehicle. The plurality of power sources comprises a hydrogen fuel cell 208, a vehicle battery 210 and a high-capacity power source 212. Figure 3B is a block diagram which schematically illustrates a power distribution module 202 (labelled PDM in Figure 3B) coupled to a fuel cell 208, a vehicle battery 210 and a high-capacity power source 212. The vehicle battery 210 may be a 12V vehicle battery. It will be appreciated that the vehicle battery 210 may be any battery suitable for powering the low-voltage electronics of an EV. The power distribution module 202 may be coupled to the plurality of power sources via the plurality of terminals 202-1, 202-2, ..., 202-N.

[047] Figure 4A is a schematic diagram illustrating more details of the hydrogen fuel cell of Figure 3B. As noted above, the hydrogen fuel cell 208 comprises an anode 208A and a cathode 208B. It will be appreciated that the hydrogen fuel cell 208 may further comprise additional standard components. As noted above, the fuel cell 208 produces power which is generated by redox reactions of air and hydrogen with the electrodes 208A, 208B. Merely by way of example, the fuel cell 208 may be an EKPO™ NM5 fuel cell, and may provide a power output of approximately 77 kW, which corresponds to an operational voltage of approximately 200 V to 285 V, and an operational current of approximately 380 A. It will be appreciated that these exemplary operational parameters are provided as an example only, and that any appropriate fuel cell may be used.

[048] The fuel cell 208 may be controlled by a fuel cell control unit 208C, FCU. The FCU 208C manages the fuel cell 208 to ensure power is efficiently generated by the fuel cell 208 for prolonged periods of time. The FCU 208C may also be used to discharge the fuel cell 208 after shut down of the electric vehicle, to ensure no residual change is left in the fuel cell (e.g. on fuel cell plates) that could hurt someone or cause damage to electronic components.

[049] Figure 4B is a schematic diagram illustrating more details of the high-capacity power sources of Figure 3B. The high-capacity power source 212 may be a high-capacity battery. Alternatively, the high-capacity power source 212 may be an ultracapacitor (or, equivalently, a supercapacitor). Further alternatively, the high-capacity power source 212 may comprise a high-capacity battery and an ultracapacitor or ultracapacitor array. In all cases, the high-capacity power source is capable of activating both the anode and cathode of the hydrogen fuel cell 202. Furthermore, it will be appreciated that the high-capacity power source may be any power source capable of activating the anode and cathode mentioned above. The high-capacity power source may store a maximum electrical energy of approximately 8 kWh, and may operate at a voltage of approximately 18 V to 54 V. It will be understood that these are merely non-limiting example values, and greater or small powers and operating voltages may be used.

[050] In cases where the high-capacity power source is a high-capacity battery, the high-capacity battery may comprise a battery array comprising a plurality of batteries and the power management system may further comprise a plurality of integrated circuits 210-1, ..., 210-N, wherein each integrated circuit is coupled to a battery of the battery array for controlling power discharge from each of the batteries. That is, the high-capacity battery may comprise multiple batteries, each with a corresponding integrated circuit for precisely controlling discharge from each of the batteries.

[051] In cases where the high-capacity power source is an ultracapacitor, the ultracapacitor may comprise a capacitor array comprising a plurality of capacitors and the power management system may further comprise a plurality of integrated circuits, wherein each integrated circuit is coupled to a capacitor of the capacitor array for controlling power discharge from each of the capacitors of the capacitor array. That is, in a similar way to the example of the high-capacity battery above, the ultracapacitor may comprise multiple capacitors, each with a corresponding integrated circuit for precisely controlling discharge from each of the capacitors. It will be appreciated that each of the capacitors of the capacitor array may themselves be considered as capacitors suitable for use in EV’s (i.e. ultracapacitors), as opposed to electrolytic capacitors that are e.g. used as components in printed circuit boards. Typically, the capacitance of the ultracapacitors and capacitors of the capacitor array is in the region of 100 F to 25,000 F, and more preferably in the range of 20F to 22,000F.

[052] Returning to Figure 3A, the power distribution module 202 is also couplable to an anode blower 214A and a cathode blower (not shown in Figure 2) of the electric vehicle. In a similar way to the plurality of power sources, the power distribution module 202 may be coupled to the anode blower 214A and the cathode blower via the plurality of terminals 202-1, 202-2, ... , 202-N.

[053] The anode blower 214A is for activating the anode 208A of the hydrogen fuel cell when a voltage applied to the anode blower is greater than an anode threshold voltage. The cathode blower is for activating the cathode 208B of the hydrogen fuel cell when a voltage applied to the cathode blower is greater than a cathode threshold voltage. That is, the anode blower 214A and cathode blower respectively activate the anode 208A and the cathode 208B of the fuel cell 208 upon application of an above-threshold voltage to the blowers.

[054] In some cases, the anode threshold voltage and the cathode threshold voltage have the same value, i.e. a uniform threshold voltage. That is, the anode 208A and cathode 208B may be activated by applying a voltage to the anode and cathode blowers which is above the uniform threshold voltage. In particular, the anode blower and the cathode blower may be operated by a controller area network, CAN, control system (not shown in Figure 2). The uniform threshold voltage may also be understood as a base voltage for activating the anode and cathode blowers. Once activated through application of the base voltage, the CAN may apply a first operational voltage to the anode blower and a second operational voltage to the cathode blower for operating the blowers upon activation. The first and second operational voltages may be adjusted by the CAN to respectively adjust the speed of the anode and cathode blowers.

[055] In other cases, the anode threshold voltage and the cathode threshold voltage have different values. Given the differing characteristics of air and hydrogen, it is common for the anode blower and the cathode blower to have different, and in some case substantially different, threshold voltages. For example, the cathode blower may operate at a cathode threshold voltage of 400Vdc (i.e. 400 volts direct current), and the anode blower may operate at an anode threshold voltage of 12Vdc or 24Vdc. It will be understood these are non-limiting example voltages. Thus, the threshold voltages may be very different. The threshold voltage may be controlled by the CAN control system, and once a base voltage is reached, the speed may be controlled by the CAN control system sending appropriate instructions to the blowers.

[056] Figure 5A is a schematic diagram showing more details of the voltage conversion module of Figure 2. As noted above, the voltage conversion module 204 is coupled to the power distribution module 202. In a similar way to the plurality of power sources 208, 210, 212, and the anode blower 214A and cathode blower above, the voltage conversion module 204 may be coupled to the power distribution module 202 via the plurality of terminals 202-1, 202-2, ..., 202-N. The voltage conversion module 204 serves to convert a voltage supplied by the vehicle battery 210 to generate a converted voltage.

[057] The present techniques make use of the converted voltage to activate the anode and cathode via the at least one processor 206. In particular, the at least one processor 206 coupled to memory is configured to: determine whether the high-capacity power source 212 is depleted below a predetermined threshold charge; and when it is determined that the high-capacity power source 212 is below the predetermined threshold charge: control the voltage conversion module 204 to convert a voltage supplied by the vehicle battery 210 to generate a converted voltage having a value greater than the anode and cathode threshold voltages; and control the power distribution module 202 to direct the converted voltage to the anode blower 214A and the cathode blower, thereby applying the converted voltage to the blowers for activating the hydrogen fuel cell 208.

[058] It will be appreciated that if the determination made by the processor 204 is that the high-capacity power source 212 is above the predetermined threshold charge, then the power distribution module 202 may be controlled to direct an above-threshold voltage to the anode blower 214A and the cathode blower to active the hydrogen fuel cell 208. This is because, if it is determined that the high-capacity power source 212 is above the predetermined threshold (i.e. there is sufficient charge stored in the high-capacity power source 212 to activate the hydrogen fuel cell 208), then the step of generating a converted voltage by the voltage conversion module 204 is not necessary.

[059] After activating the fuel cell 208, the present techniques advantageously provide a way of charging the vehicle battery 210 and the high-capacity power source 212. That is, once the “back-up” power source of the vehicle battery 210 is used to activate the fuel cell 208, the state of charge (SoC) of the vehicle battery 210 may be restored. This is advantageous because charge may be restored to the vehicle battery and to resume “normal” operation of the EV. In other words, the at least one processor 204 may be further configured to control the power distribution module 202 to direct power from the hydrogen fuel cell 208 to the vehicle battery 210 for thereby charging the vehicle battery 210, once the hydrogen fuel cell 208 is activated.

[060] Similarly, it is important that charge is restored to the high-capacity power source 212 for resuming standard operation of the EV. That is, the at least one processor 204 may be further configured to control the power distribution module 202 to direct power from the hydrogen fuel cell 208 to the high-capacity power source 212 for charging the high-capacity power source 212, once the hydrogen fuel cell 208 is activated.

[061] As noted above, the high-capacity power source 212 may be a high-capacity battery or an ultracapacitor respectively comprising an array of batteries or capacitors. In cases where the high-capacity power source 212 is a high-capacity battery comprising an array of batteries, the at least one processor may be configured to determine whether the high-capacity power source 212 is depleted below the predetermined threshold by determining, using the plurality of integrated circuits, whether a total charge amount aggregated over all of the batteries in the battery array is below the predetermined threshold. In cases where the high-capacity power source 212 is an ultracapacitor comprising an array of capacitors, the at least one processor may be configured to determine whether the high-capacity power source is depleted below the predetermined threshold by determining, using the plurality of integrated circuits, whether a total charge amount aggregated over all of the capacitors in the capacitor array is below the predetermined threshold.

[062] The voltage conversion module 204 may be a bi-directional voltage conversion module. That is, the voltage conversion module 204 may be configured to both increase and decrease voltages, in different modes of operation. This advantageously ensures the flexibility of the present techniques for directing power to different components, depending on whether or not the hydrogen fuel cell 208 is activated.

[063] In particular, the bi-directional voltage conversion module may be configured to generate the converted voltage in a first mode of operation for increasing voltage. In this case, the at least one processor 206 may be configured to control the bi-directional voltage conversion module to generate the converted voltage by setting the bi-directional voltage conversion module to the first mode of operation. That is, the first mode of operation may be understood as a first “direction” whereby the voltage of the vehicle battery 210 is increased for activating the blowers of the fuel cell 208.

[064] Accordingly, the bi-directional voltage conversion module may be further configured to generate a down converted voltage in a second mode of operation for decreasing voltages. In this case, the at least one processor may be further configured to: when it is determined that the high-capacity power source is above the predetermined threshold: control the power distribution module to direct power from the high-capacity power source to the anode blower and the cathode blower for activating the hydrogen fuel cell; and control the bi-directional voltage conversion module to generate the down converted voltage, using the second mode of operation, for re-charging the vehicle battery whilst the hydrogen fuel cell is activated using power supplied to the bi-directional voltage conversion module by the power distribution module. The at least one processor may be configured to control the bi-directional voltage conversion module to generate the converted voltage by setting the bi-directional voltage conversion module to the second mode of operation.

[065] That is, the second mode of operation may be understood as a second “direction” whereby voltages are decreased for (re-)charging the vehicle battery whilst the hydrogen fuel cell is activate. The second mode of operation may be considered a “conventional” mode of operation, in line with how EV’s conventionally operate to charge the vehicle battery whilst the EV is running. In this case, power is supplied to the bi-directional voltage conversion module by the power distribution module 202. As noted above, multiple high-voltage power sources are couplable to the power distribution module 202, such as the high-capacity power source 212. In essence, the second mode of operation described above amounts to the supply of power to the bi-directional voltage conversion module by these high-voltage power sources via the power distribution module 202, and a down conversion of this power for re-charging the vehicle battery.

[066] More specifically, the voltage conversion module may be a bi-directional DC-to-DC converter. That is, the voltage conversion module may be capable of converting DC signals to DC signals with a higher or lower voltage.

[067] The power management system 200 may further comprise a first cooling system 216 for cooling the voltage conversion module 204. Merely by way of example, the first cooling system may have a power of approximately 2 kW and operate at a voltage of approximately 24 V. The first cooling system 216 may be a water pump. That is, the first cooling system 216 ensures the dissipation of heat generated by operation of the voltage conversion module during its operation.

[068] As noted above, the operational voltage of the hydrogen fuel cell 208 is normally determined by the characteristics of the fuel cell 208. There is typically a discrepancy between the operational voltage of the fuel cell 208 and that required by the power distribution module 202. Thus, the power distribution module 202 may be coupled to the hydrogen fuel cell by a unidirectional voltage conversion module 218, as shown in Figure 5B. The power management system 200 may further comprise a second cooling system 220 for cooling the unidirectional voltage conversion module 218. In a similar way to the first cooling system above 216, the second cooling system 220 may be a water pump. However, the second cooling system may operate at a higher voltage than the first cooling system 216. For example, the second cooling system 220 may be a high-voltage cooling system, and may operate at a voltage of approximately 400 V, and operate at a power of approximately 2 kW. That is, the first 216 and second 220 cooling system may differ substantially in their operational voltages, but may have similar power output.

[069] Figure 6 is a block diagram of an electric vehicle comprising any of the power management systems described in relation to Figures 2 to 5B. The electric vehicle 20 comprises: a plurality of power sources comprising: a hydrogen fuel cell 208 comprising an anode 208A and a cathode 208B; a vehicle battery 210; and a high-capacity power source 212; an anode blower 214A for activating the anode 208A of the hydrogen fuel cell when a voltage applied to the anode blower 214A is greater than a threshold voltage; a cathode blower 214B for activating the cathode 208B of the hydrogen fuel cell 208 when a voltage applied to the cathode blower 214B is greater than the threshold voltage; and the power management system 200 as described above in relation to the first aspect for activating the hydrogen fuel cell. That is, in addition to providing a power management system that may be retrofitted to existing EV’s, the present techniques also provide an EV comprising the power management system described above. The features described above in relation to Figures 2 to 5B equally to the power management system 200 of Figure 6, and are not repeated for conciseness.

[070] Figure 7 is a flowchart of example steps in a method for operating an electric vehicle. That is, Figure 7 shows the steps which may be performed by the at least one processor 204 described above. At step S100, the method comprises: determining whether the high-capacity power source is depleted below a predetermined threshold charge. At step S102 when it is determined that the high-capacity power source is below the predetermined threshold charge, the method comprises: controlling a voltage conversion module of the electric vehicle to convert a voltage supplied by the battery to generate a converted voltage having a value greater than the threshold voltage of an anode blower of the electric vehicle and a cathode blower of the electric vehicle, wherein the anode blower activates an anode of the hydrogen fuel cell when a voltage applied to the anode blower is greater than the threshold voltage and wherein the cathode blower activates a cathode of the hydrogen fuel cell when a voltage applied to the cathode blower is greater than the threshold voltage. At step S104, the method further comprises controlling a power distribution module of the electric vehicle to direct the converted voltage to the anode blower and the cathode blower to activate the hydrogen fuel cell.

[071] The method may further comprise controlling the power distribution module to direct power from the hydrogen fuel cell to the vehicle battery to thereby charge the vehicle battery, once the fuel cell is activated.

[072] It will be appreciated that if the determination at step S100 is that the high-capacity power source is above the predetermined threshold charge, then the power distribution module may be controlled to direct an above-threshold voltage to the anode blower and the cathode blower to active the hydrogen fuel cell. This is because, if it is determined that the 5 high-capacity power source is above the predetermined threshold (i.e. there is sufficient charge to activate the hydrogen fuel cell), then the step of generating a converted voltage is not necessary.

[073] Those skilled in the art will appreciate that while the foregoing has described what is 10 considered to be the best mode and where appropriate other modes of performing present techniques, the present techniques should not be limited to the specific configurations and methods disclosed in this description of the preferred embodiment. Those skilled in the art will recognise that present techniques have a broad range of applications, and that the embodiments may take a wide range of modifications without departing from any inventive 15 concept as defined in the appended claims.

Claims

1. A power management system for an electric vehicle, the power management system comprising:a power distribution module couplable to:a plurality of power sources of the electric vehicle, the plurality of power sources comprising:a hydrogen fuel cell comprising an anode and a cathode;a vehicle battery; anda high-capacity power source;an anode blower of the electric vehicle, wherein the anode blower is for activating the anode of the hydrogen fuel cell when a voltage applied to the anode blower is greater than an anode threshold voltage; anda cathode blower of the electric vehicle, wherein the cathode blower is for activating the cathode of the hydrogen fuel cell when a voltage applied to the cathode blower is greater than a cathode threshold voltage;a voltage conversion module coupled to the power distribution module; andat least one processor coupled to memory and configured to:determine whether the high-capacity power source is depleted below a predetermined threshold charge; andwhen it is determined that the high-capacity power source is below the predetermined threshold charge:control the voltage conversion module to convert a voltage supplied by the battery to generate a converted voltage having a value greater than the anode and cathode threshold voltages; andcontrol the power distribution module to direct the converted voltage to the anode blower and the cathode blower, thereby applying the converted voltage to the blowers for activating the hydrogen fuel cell.

2. The power management system as claimed in claim 1 wherein the at least one processor is further configured to control the power distribution module to direct power from the hydrogen fuel cell to the vehicle battery to thereby charge the vehicle battery, once the hydrogen fuel cell is activated.

3. The power management system as claimed in claim 1 or 2 wherein the voltage conversion module is a bi-directional voltage conversion module configured to generate the converted voltage in a first mode of operation for increasing voltages.

4. The power management system as claimed in claim 3 wherein the at least one processor is configured to control the bi-directional voltage conversion module to generate the converted voltage by setting the bi-directional voltage conversion module to the first mode of operation.

5. The power management system as claimed in claim 3 or 4 wherein the bi-directional voltage conversion module is further configured to generate a down converted voltage in a second mode of operation for decreasing voltages.

6. The power management system as claimed in claim 5 wherein the at least one processor is further configured to:when it is determined that the high-capacity power source is above the predetermined threshold:control the power distribution module to direct power from the high-capacity power source to the anode blower and the cathode blower for activating the hydrogen fuel cell; andcontrol the bi-directional voltage conversion module to generate the down converted voltage, using the second mode of operation, for re-charging the vehicle battery whilst the hydrogen fuel cell is activated using power supplied to the bi-directional voltage conversion module by the power distribution module.

7. The power management system as claimed in claim 6 wherein the at least one processor is configured to control the bi-directional voltage conversion module to generate the converted voltage by setting the bi-directional voltage conversion module to the second mode of operation.

8. The power management system as claimed in any of claims 1 to 7 wherein the high-capacity power source is a high-capacity battery.

9. The power management system as claimed in claim 8 wherein the high-capacity battery comprises a battery array formed of a plurality of batteries and wherein the power management system further comprises a plurality of integrated circuits, wherein eachintegrated circuit is coupled to a battery of the battery array for controlling power discharge from each of the batteries of the battery array.

10. The power management system as claimed in claim 9 wherein the at least one processor is configured to determine whether the high-capacity power source is depleted below the predetermined threshold by determining, using the plurality of integrated circuits, whether a total charge amount aggregated over all of the plurality of batteries is below the predetermined threshold.

11. The power management system as claimed in any of claims 1 to 7 wherein the high-capacity power source is an ultracapacitor.

12. The power management system as claimed in claim 11 wherein the ultracapacitor comprises a capacitor array comprising a plurality of capacitors and wherein the power management system further comprises a plurality of integrated circuits, wherein each integrated circuit is coupled to a capacitor of the capacitor array for controlling power discharge from each of the capacitors of the capacitor array.

13. The power management system as claimed in claim 12 wherein the at least one processor is configured to determine whether the high-capacity power source is depleted below a predetermined threshold by determining, using the plurality of integrated circuits, whether a total charge amount aggregated over all of the plurality of capacitors is below the predetermined threshold.

14. The power management system as claimed in any preceding claim wherein the at least one processor is further configured to control the power distribution module to direct power from the hydrogen fuel cell to the high-capacity power source for charging the high-capacity power source, once the hydrogen fuel cell is activated.

15. The power management system as claimed in any preceding claim further comprising a first cooling system for cooling the voltage conversion module.

16. The power management system as claimed in claim 15 wherein the first cooling system comprises a water pump.

17. The power management system as claimed in any preceding claim wherein the power distribution module is coupled to the hydrogen fuel cell by a unidirectional voltage conversion module.

18. The power management system as claimed in claim 17, when dependent on claim 15 or 16, further comprising a second cooling system for cooling the unidirectional voltage conversion module.

19. The power management system as claimed in claim 18 wherein the second cooling system comprises a water pump.

20. The power management system as claimed in any preceding claim wherein the voltage conversion module is a bi-directional DC-to-DC converter.

21. An electric vehicle comprising:a plurality of power sources comprising:a hydrogen fuel cell comprising an anode and a cathode;a vehicle battery; anda high-capacity power source;an anode blower for activating the anode of the hydrogen fuel cell when a voltage applied to the anode blower is greater than an anode threshold voltage;a cathode blower for activating the cathode of the hydrogen fuel cell when a voltage applied to the cathode blower is greater than a cathode threshold voltage; andthe power management system of any of claims 1 to 20 for activating the hydrogen fuel cell.

22. A method for operating an electric vehicle, the electric vehicle comprising a plurality of power sources including a hydrogen fuel cell, a vehicle battery and a high-capacity power source, the method comprising:determining whether the high-capacity power source is depleted below a predetermined threshold charge; andwhen it is determined that the high-capacity power source is below the predetermined threshold charge:controlling a voltage conversion module of the electric vehicle to convert a voltage supplied by the vehicle battery to generate a converted voltage having a value greater than anode and cathode threshold voltages of, respectively, an anode blower of theelectric vehicle and a cathode blower of the electric vehicle, wherein the anode blower activates an anode of the hydrogen fuel cell when a voltage applied to the anode blower is greater than the anode threshold voltage and wherein the cathode blower activates a cathode of the hydrogen fuel cell when a voltage applied to the cathode blower is greater5 than the cathode threshold voltage; andcontrolling a power distribution module of the electric vehicle to direct the converted voltage to the anode blower and the cathode blower to activate the hydrogen fuel cell.10 23. The method as claimed in claim 22 further comprising controlling the power distribution module to direct power from the hydrogen fuel cell to the vehicle battery to thereby charge the vehicle battery, once the fuel cell is activated.

24. A non-transitory data carrier carrying code which, when implemented on a processor, 15 causes the processor to carry out the method of any of claims 22 and 23.

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