WO2020197389A1

WO2020197389A1 - A method for operating a hydrogen fuel cell system in a vehicle as well as a hydrogen fuel cell system for operation in said vehicle

Info

Publication number: WO2020197389A1
Application number: PCT/NL2020/050199
Authority: WO
Inventors: Jochem Evert HUIJGEN
Original assignee: Hymove Holding B.V.
Priority date: 2019-03-26
Filing date: 2020-03-25
Publication date: 2020-10-01
Also published as: EP3947028A1; NL2022815B1; CN113795404A

Abstract

A method for operating a hydrogen fuel cell system in a vehicle, wherein said vehicle comprises a Vehicle Control Unit, VCU, for controlling power provided to a drive train of said vehicle originating from any of a Battery Management System, BMS, comprising at least one battery, and said hydrogen fuel cell system which comprises a plurality of hydrogen fuel cells, wherein said hydrogen fuel cell system further comprises a Fuel Cell Control Unit, FCCU, and a Direct Current, DC-to-DC converter, said method comprises the steps of receiving an indication of a state of charge of said at least one battery, determining from said indication of said state of charge of said at least one battery, and from an instantaneous requested amount of power, a demand for power that is to be provided by said plurality of hydrogen fuel cells, requesting said demand for power that is to be provided by said plurality of hydrogen fuel cells, demanding an amount of current that is to be provided by said plurality of hydrogen fuel cells and supplying said demanded amount of current.

Description

Title: A method for operating a hydrogen fuel cell system in a vehicle as well as a hydrogen fuel cell system for operation in said vehicle.

Description

The present disclosure is related to a method for operating a hydrogen fuel cell system in a vehicle.

A hydrogen fuel cell system, in accordance with the present disclosure, comprises a plurality of hydrogen fuel cells. Each of these fuel cells may comprise a fuel cell stack and a controller. A fuel cell stack is an electrochemical cell that is able to convert the chemical energy from hydrogen fuel and oxygen into electricity. The electricity may be used, for example, to empower an electrical motor.

Hydrogen fuel cell stacks are thus not the same as regular batteries. Fuel cells work on the basis of fuel that is provided to the fuel cells, i.e. in the form of hydrogen. In a battery, electricity is generated based on chemicals that are already present in the battery.

The present disclosure is directed to the concept that a hydrogen fuel cell system is to operate alongside at least one battery, in a vehicle. Whenever the vehicle demands power, for example due to the fact that the throttle pedal is activated, the power may originate from the hydrogen fuel cell system and/or from the at least one battery.

One of the drawbacks of systems in which both the hydrogen fuel cell system and the at least one battery are operated in a vehicle is related to the life time of the battery and/or of the hydrogen fuel cell system.

It is an objective of the present disclosure to provide for a method for operating a hydrogen fuel cell system in a vehicle.

The present disclosure provides, in a first aspect, in a method for operating a hydrogen fuel cell system in a vehicle, wherein said vehicle comprises a Vehicle Control Unit, VCU, for controlling power provided to a drive train of said vehicle originating from any of a Battery Management System, BMS, comprising at least one battery, and said hydrogen fuel cell system which comprises a plurality of hydrogen fuel cells, wherein said hydrogen fuel cell system further comprises a Fuel Cell Control Unit, FCCU, and a Direct Current, DC-to-DC converter.

The method comprises the steps of: receiving, by said FCCU, from said VCU, an indication of a state of charge of said at least one battery;

determining, by said FCCU, from said indication of said state of charge of said at least one battery, and from an instantaneous requested amount of power, a demand for power that is to be provided by said plurality of hydrogen fuel cells;

requesting, by said FCCU, to said DC-to-DC converter, said demand for power that is to be provided by said plurality of hydrogen fuel cells;

demanding, by said DC-to-DC converter, from said FCCU, an amount of current that is to be provided by said plurality of hydrogen fuel cells;

supplying, by said FCCU, from said plurality of hydrogen fuel cells, to said DC-to-DC converter, said demanded amount of current.

The inventors have found that the VCU should not be in control in demanding the amount of power that is to be supplied by the hydrogen fuel cell system. The VCU is, typically, functionality that is physically separated from the FCCC. The VCU may not be aware of the characteristics of the plurality of hydrogen fuel cells. That is, the VCU may not know how to efficiently stress a hydrogen fuel cell.

As such, the inventors have found a method in which the FCCU is in charge. The FCCU may determine, based on the state of charge of the at least one battery, how much the plurality of hydrogen fuel cells are to be stressed. The FCCU may have in depth knowledge of the plurality of hydrogen fuel cells, which the FCCU can utilize for determining how much the hydrogen fuel cells may be stressed.

In accordance with the present disclosure, an indication of a state of charge of the at least one battery may be considered as information as to how full the at least one battery actually is. Such information may be used by the FCCU to determine how much electrical power may be drained from the at least one battery. The inventors have noted that the lifespan of a battery may be related to the state of charge in which the battery is kept. As such, for example, it may be beneficial to not fully drain the battery as that could be disadvantageous for the life span of the battery.

Following the above, the FCCU determines, from the indication of the state of charge of the at least one battery and from an instantaneous requested amount of power, a demand for power that is to be provided by the plurality of hydrogen fuel cells is determined. Here, the FCCU may consider a power-ramp up that is beneficial for the life span of the hydrogen fuel cells and may consider a power-ramp up that is beneficial for the life span of the at least one battery.

More specifically, the FCCU may follow a preferred power-ramp up curve for drawing power from the plurality of hydrogen fuel cells and may entrust the VCU to draw to remaining power, i.e. the deficient power being the difference between the instantaneous requested amount of power and the power-ramp up curve, from the at least one battery.

Following the above, the DC-to-DC converter will request the amount of current that is to be provided by the plurality of hydrogen fuel cells based on the demand of power that is to be provided by the plurality of hydrogen fuel cells.

It is noted that, in accordance with the present disclosure, the DC-to- DC controller is controlled by the FCCU. For example, the FCCU may send a current request by a bus, for example CANBUS, to the DC-to-DC converter. The DC-to-DC converter may then send back what amount of current is flowing through the DC-to- DC converter, for example a plurality of times per second. This information may be used by the FCCU to control the plurality of fuel cells so that the current can be maintained. As mentioned above, one of the advantages of this is that the FCCU is in control of the amount of power that is to be provided by the plurality of hydrogen fuel cells.

The present application is thus directed to the concept that the FCCU determines the amount of power that is to be provided by the plurality of hydrogen fuel cells based on, amongst other, the state of charge of the at least one battery.

Another advantage of the present disclosure is that the FCCU is physically separated from the VCU. The FCCU is responsible for controlling the fuel cells. The VCU is responsible for controlling the vehicle. These two blocks operate independently from each other. This has the benefit that the FCCU is able to assure that the fuel cells are shut down safely, even when the VCU shuts down or when the VCU experiences some sort of errors or the VCU experiences errors. As the FCCU and the VCU are physically, and operationally, separated, the FCCU may assure that the fuel cells are controlled safely.

The above is, for example, true for cases when there is a collision with the respective vehicle, a leakage occurs in the fuel cells, sensors start to malfunction or anything alike. It is further noted that the DC-to-DC converter may be located in between the plurality of hydrogen fuel cells and the vehicle, for example the at least one battery.

IN accordance with the present disclosure, the DC-to-DC converter may comprise a DC-to-DC converter controller that is responsible for controlling the operation of the DC-to-DC converter. The DC-to-DC converter controller may, for example, receive the demand for power, and may send a demand for an amount of current, as specified in the present disclosure.

The instantaneous requested power, in accordance with the present disclosure, may be defined as the total amount of power that is requested by the vehicle, more specifically, by the driver of the vehicle. The instantaneous requested power may, for example, be based on the gas pedal, i.e. the throttle, of the vehicle. The instantaneous requested power may be communicated to the FCCU in several ways.

In accordance with the present disclosure, the methods comprise a step of receiving, by said FCCU, from said VCU, an indication of a state of charge of said at least one battery. This may be accomplished in a variety of ways. For example, the state or charge of the at least one battery may be calculated by a Battery Management System, BMS, and may be send via a bus, for example CANBUS, to the VCU. The VCU may then communicate the state of charge to the FCCU via a bus, for example a CANBUS.

In an example, the step of determining comprises:

determining, by said FCCU, from said indication of said state of charge of said at least one battery and from said instantaneous requested amount of power, a demand for power that is to be provided by said plurality of hydrogen fuel cells such that an expected state of charge of said at least one battery does not fall under a predetermined threshold.

The advantage of this particular example is that the life span of the at least one battery is ensured.

In a further example, the predetermined threshold is between 30% - 55%, preferably between 45% - 55%, more preferably around 50%.

In an example, the method further comprises the steps of: receiving, by said FCCU, from said plurality of hydrogen fuel cells fuel cell information comprising any of:

voltages of each of said plurality of hydrogen fuel cells; voltage of said plurality of hydrogen fuel cells as a whole; relative voltage of a weakest cell compared to an average voltage of each of said plurality of hydrogen fuel cells;

wherein said step of determining comprises:

determining, by said FCCU, said demand for power that is to be provided by said plurality of hydrogen fuel cells also based on said fuel cell information.

The advantage of this particular example is that the FCCU is able to steer the plurality of fuel cells such based on information that may directly affect the life span.

In a further example, the FCCU comprises a power-up curve and a power-down curve for indicating a preferred ramping up curve for increasing power from said plurality of fuel cells and a preferred ramping down curve for reducing power from said plurality of fuel cells, respectively, and wherein said step of determining comprises:

determining, by said FCCU, said demand for power that is to be provided by said plurality of hydrogen fuel cells also based on any of said power-up curve and said power-down curve.

Preferably, the FCCU controls the amount of power to be provided by the plurality of hydrogen fuel cells such that the actually delivered power over time corresponds to the power-up curve. This ensures that the life span of the plurality of fuel cells is improved.

In a second aspect, there is provided a hydrogen fuel cell system for operation in a vehicle, wherein said vehicle comprises a Vehicle Control Unit, VCU, for controlling power provided to a drive train of said vehicle originating from any of a Battery Management System, BMS, comprising at least one battery, and said hydrogen fuel cell system which comprises a plurality of hydrogen fuel cells, wherein said hydrogen fuel cell system further comprises a Fuel Cell Control Unit, FCCU, and a Direct Current, DC-to-DC converter.

The FCCU further comprising:

receive equipment arranged for receiving, from said VCU, an indication of a state of charge of said at least one battery; process equipment arranged for determining, from said indication of said state of charge of said at least one battery, and from an instantaneous requested amount of power, a demand for power that is to be provided by said plurality of hydrogen fuel cells;

request equipment arranged for requesting, to said DC-to-DC converter, said demand for power that is to be provided by said plurality of hydrogen fuel cells;

demand equipment arranged for demanding, from said FCCU, an amount of current that is to be provided by said plurality of hydrogen fuel cells;

supply equipment arranged for supplying, to said DC-to-DC converter, said demanded amount of current.

It is noted that the advantages and definitions as disclosed with respect to the examples of the first aspect of the present disclosure, being the method for operating a hydrogen fuel cell system in a vehicle also corresponds to the examples of the second aspect of the present disclosure, being the hydrogen fuel cell system for operation in a vehicle.

In an example, the process equipment is further arranged for determining, from said indication of said state of charge of said at least one battery and from said instantaneous requested amount of power, a demand for power that is to be provided by said plurality of hydrogen fuel cells such that an expected state of charge of said at least one battery does not fall under a predetermined threshold.

In a further example, the predetermined threshold is 50%.

In another example, the receive equipment is further arranged for receiving, from said plurality of hydrogen fuel cells fuel cell information comprising any of:

and wherein said process equipment is further arranged for determining said demand for power that is to be provided by said plurality of hydrogen fuel cells also based on said fuel cell information.

In a further example, the FCCU comprises a power-up curve and a power-down curve for indicating a preferred ramping up curve for increasing power from said plurality of fuel cells and a preferred ramping down curve for reducing power from said plurality of fuel cells, respectively, and wherein said process equipment is further arranged for determining said demand for power that is to be provided by said plurality of hydrogen fuel cells also based on any of said power-up curve and said power-down curve.

In a third aspect, there is provided a computer program product comprising a computer readable medium having instructions stored thereon which, when executed by a hydrogen fuel cell system cause said hydrogen fuel cell system to implement a method in accordance with any of the method examples as provided above.

The above-mentioned and other features and advantages of the disclosure will be best understood from the following description referring to the attached drawings. In the drawings, like reference numerals denote identical parts or parts performing an identical or comparable function or operation.

Brief description of the Figures

Figure 1 schematically shows a schematic diagram illustrating the cooperation of batteries and a fuel cell system in accordance with the present disclosure.

Figure 2 schematically shows a schematic diagram illustrating a hydrogen fuel cell system in accordance with the present disclosure.

Detailed description

Figure 1 schematically shows a schematic diagram 1 illustrating the cooperation of batteries 3 and a fuel cell system in accordance with the present disclosure.

The drive train of the vehicle is indicated with reference numeral 2. The drive train 2 of a vehicle is the group of components that deliver power to the driving wheels. This typically excludes the engine or motor that generates the power. In contrast, the powertrain is considered to include both the engine or motor and the drivetrain. In this particular scenario’s the power originates from either the batteries 3 or the hydrogen fuel cells, or a combination thereof. The power delivered 12 to the drive train 2 is controlled by a Vehicle Control Unit, VCU, 9. The VCU 9 retrieves 13 power from the batteries 3 or is provided 14 with power originating from hydrogen fuel cells.

The present disclosure is directed to a method for operating a hydrogen fuel cell system in a vehicle. The fuel cell system comprises a Fuel Cell Control Unit, FCCU, 7 a Direct Current, DC to DC converter 6 and a plurality of hydrogen fuel cells.

The schematic diagram 1 denotes a single functional block referred to as batteries 3. It is noted that the present disclosure may deal with a Battery Management System, BMS, comprising at least one battery. Typically, multiple batteries may be provided for storing sufficient energy for empowering the vehicle. The batteries may be recharged by inducing electrical energy during braking of the vehicle.

The method may initiate by receiving 1 1 , by said FCCU 7, from the VCU 9, an indication of a state of charge of the batteries 3. The inventors have noted that, in order to increase the life span of the batteries, the batteries should ideally be operated in an operating window of between 40% - 65%.

In accordance with the present disclosure, the FCCU 7 is separate from the VCU 9, and is in charge of distributing the requested power among the hydrogen fuel cells and the batteries 3. In order to do so, as mentioned above, the FCCU 7 may receive the indication of the state of charge of the batteries 3.

The FCCU 7 may then determine, from the received indication of the state of charge as well as from an instantaneous requested amount of power, a demand for power that is to be provided by the plurality of hydrogen fuel cells.

In other words, the FCCU 7 may, for example, determine how much power is to be provided by the plurality of hydrogen fuel cells such that the state of charge of the batteries 3 may not fall below a particular threshold. This improves the lifespan of the plurality of fuel cells.

Next, the FCCU 7 may request 15 at said DC-to-DC converter 6, the demand for power that is to be provided by the plurality of hydrogen fuel cells. The DC-to-DC convert then demands 16 from the FCCU 7, an amount of current that is to be provided by the plurality of hydrogen fuel cells, which is, finally, supplied 17, by the FCCU 7 to the DC-to-DC converter 6.

It is noted that the current demand is denoted with reference numeral 4, the current supply is denoted with reference numeral 8, the state of charge is denoted with reference numeral 10 and the fuel cells are denoted with reference numeral 5.

Figure 2 schematically shows a schematic diagram 51 illustrating a hydrogen fuel cell system in accordance with the present disclosure.

The hydrogen fuel cell system 51 is arranged for operation in a vehicle, wherein said vehicle comprises a Vehicle Control Unit, VCU, for controlling power provided to a drive train of said vehicle originating from any of a Battery Management System, BMS, comprising at least one battery, and said hydrogen fuel cell system which comprises a plurality of hydrogen fuel cells, wherein said hydrogen fuel cell system further comprises a Fuel Cell Control Unit, FCCU, and a Direct Current, DC-to-DC converter.

The FCCU further comprising:

receive equipment 52 arranged for receiving, from said VCU, an indication of a state of charge of said at least one battery;

process equipment 53 arranged for determining, from said indication of said state of charge of said at least one battery, and from an instantaneous requested amount of power, a demand for power that is to be provided by said plurality of hydrogen fuel cells;

request equipment 56 arranged for requesting, to said DC-to-DC converter, said demand for power that is to be provided by said plurality of hydrogen fuel cells;

demand 54 equipment arranged for demanding, from said FCCU, an amount of current that is to be provided by said plurality of hydrogen fuel cells;

supply equipment 55 arranged for supplying, to said DC-to-DC converter, said demanded amount of current.

Other variations to the disclosed examples can be understood and effected by those skilled in the art in practicing the claimed disclosure, from a study of the drawings, the disclosure and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article“a” or “an” does not exclude a plurality. A single processor or other unit may fulfil the Functions of several items recited in the claims. The mere fact that certain measures Are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not construed as limiting scope thereof.

The present disclosure is not limited to the examples as disclosed above, and can be modified and enhanced by those skilled in the art beyond the scope of the present disclosure as disclosed in the appended claims without having to apply inventive skills.

Claims

1. A method for operating a hydrogen fuel cell system in a vehicle, wherein said vehicle comprises a Vehicle Control Unit, VCU, for controlling power provided to a drive train of said vehicle originating from any of a Battery Management System, BMS, comprising at least one battery, and said hydrogen fuel cell system which comprises a plurality of hydrogen fuel cells, wherein said hydrogen fuel cell system further comprises a Fuel Cell Control Unit, FCCU, and a Direct Current, DC- to-DC converter, said method comprises the steps of:

receiving, by said FCCU, from said VCU, an indication of a state of charge of said at least one battery;

2. A method in accordance with claim 1 , wherein said step of determining comprises:

3. A method in accordance with claim 2, wherein said predetermined threshold is 50%.

4. A method in accordance with any of the previous claims, wherein said method further comprises the steps of:

receiving, by said FCCU, from said plurality of hydrogen fuel cells fuel cell information comprising any of: voltages of each of said plurality of hydrogen fuel cells;

voltage of said plurality of hydrogen fuel cells as a whole; relative voltage of a weakest cell compared to an average voltage of each of said plurality of hydrogen fuel cells;

wherein said step of determining comprises:

5. A method in accordance with any of the previous claims, wherein said FCCU comprises a power-up curve and a power-down curve for indicating a preferred ramping up curve for increasing power from said plurality of fuel cells and a preferred ramping down curve for reducing power from said plurality of fuel cells, respectively, and wherein said step of determining comprises:

6. A hydrogen fuel cell system for operation in a vehicle, wherein said vehicle comprises a Vehicle Control Unit, VCU, for controlling power provided to a drive train of said vehicle originating from any of a Battery Management System, BMS, comprising at least one battery, and said hydrogen fuel cell system which comprises a plurality of hydrogen fuel cells, wherein said hydrogen fuel cell system further comprises a Fuel Cell Control Unit, FCCU, and a Direct Current, DC-to-DC converter, said FCCU further comprising:

receive equipment arranged for receiving, from said VCU, an indication of a state of charge of said at least one battery;

process equipment arranged for determining, from said indication of said state of charge of said at least one battery, and from an instantaneous requested amount of power, a demand for power that is to be provided by said plurality of hydrogen fuel cells;

demand equipment arranged for demanding, from said FCCU, an amount of current that is to be provided by said plurality of hydrogen fuel cells; supply equipment arranged for supplying, to said DC-to-DC converter, said demanded amount of current.

7. A hydrogen fuel cell system in accordance with claim 6, wherein said process equipment is further arranged for determining, from said indication of said state of charge of said at least one battery and from said instantaneous requested amount of power, a demand for power that is to be provided by said plurality of hydrogen fuel cells such that an expected state of charge of said at least one battery does not fall under a predetermined threshold.

8. A hydrogen fuel cell system in accordance with claim 7, wherein said predetermined threshold is 50%.

9. A hydrogen fuel cell system in accordance with any of the claims 7 -

8, wherein said receive equipment is further arranged for receiving, from said plurality of hydrogen fuel cells fuel cell information comprising any of:

10. A hydrogen fuel cell system in accordance with any of the claims 7 -

9, wherein said FCCU comprises a power-up curve and a power-down curve for indicating a preferred ramping up curve for increasing power from said plurality of fuel cells and a preferred ramping down curve for reducing power from said plurality of fuel cells, respectively, and wherein said process equipment is further arranged for determining said demand for power that is to be provided by said plurality of hydrogen fuel cells also based on any of said power-up curve and said power-down curve.

1 1. A computer program product comprising a computer readable medium having instructions stored thereon which, when executed by a hydrogen fuel cell system cause said hydrogen fuel cell system to implement a method in accordance with any of the claims 1 - 6.