DE102019209867A1 - Electrically powered vehicle with a fuel cell as the energy system - Google Patents

Abstract

The invention relates to an electrically powered vehicle with a traction network (T), in which a traction battery (7) supplies an electric drive unit of the vehicle with electrical energy (Eel), and with an auxiliary energy supply system (APU) with a fuel cell unit (FC) that is independent provides electrical energy (Eel) and thermal energy (Eth) from the traction network (T) for consumers, the auxiliary energy supply system (APU) having a control unit (19) which, when an energy demand signal (SW, Sl) is present, the fuel cell unit (FC) activated, when activated at least one electrical consumer (21) can be supplied with electrical energy (Eel) and / or at least one thermal consumer (23) can be supplied with thermal energy (Eth). According to the invention, the vehicle has thermal and electrical energy stores (7, 25), and that excess energy (ΔE) in the form of electrical energy (Eel) or excess energy (ΔE) which is provided when the fuel cell unit (FC) is activated and is not required for supplying energy to the consumer thermal energy (Eth) can be stored in the electrical or thermal energy store (7, 25).

Description

The invention relates to an electrically operated vehicle according to the preamble of claim 1 and a method for operating such a vehicle.

When using electrically powered vehicles, one of the challenges is to ensure that the vehicle is adequately and reliably supplied with energy. For this purpose and also for economic reasons, the energy supply is divided into different networks. Electrically powered vehicles are often equipped with a traction network that is used solely to drive the vehicle. In addition to the drive, additional electrical consumers are now provided in such vehicles. These additional consumers include, for example, vehicle lights, multimedia systems and interior lighting. An auxiliary power supply system in the form of a fuel cell unit is provided in a vehicle of the generic type for these additional consumers, which are mostly operated in the low voltage range with low power. For this purpose, the fuel cell unit is made small in order to be optimally matched to the actual electrical energy consumption of the additional consumers. This means that the electrical power of the fuel cell unit is dimensioned to be exactly large enough that the majority of the electrical energy provided by the fuel cell unit can be consumed by the additional electrical consumers. In this way, efficient operation of the fuel cell is guaranteed.

A disadvantage of these vehicles is that the potential performance of fuel cell units is not nearly exhausted, which means that the operation of the vehicles is inefficient.

An energy-supplying trailer for electric cars is known from G 94 04 746. From the DE 10 2016 217 615 A1 a method for charging a battery-operated vehicle is known.

The underlying task is therefore to provide an electrically operated vehicle with increased efficiency.

The object is achieved by the features of claim 1 or 10. Preferred developments of the invention are disclosed in the subclaims.

According to the characterizing part of claim 1, the electrically operated vehicle has a thermal and an electrical energy store. In this electrical or thermal energy store, an excess energy that is provided when a fuel cell unit is activated and is not required for supplying energy to the consumer can be stored in the form of electrical or thermal energy. This means that both the heat and the electrical energy provided by the fuel cell unit are used and, if necessary, also stored. This makes the vehicle more efficient to operate.

The solution according to the invention can be used, for example, in a vehicle combination consisting of a tractor and a caravan. As an auxiliary power supply system ( APU ) the caravan contains a fuel cell. This fuel cell is only activated when a controller decides that the fuel cell needs to be activated (start-stop operation). This means that the fuel cell can be activated as required. If such a need has now been detected, the fuel cell in the caravan generates electrical energy. The electrical energy can be referred to as useful energy and used for operation, such as light, radio, and / or stove, etc. For this purpose, the fuel cell provides the electrical energy that it passes on to the consumers via an electrical current flow. In addition to the direct use of electrical energy, the electrical energy provided by the fuel cell can also be temporarily stored in batteries. These batteries can be installed in the tractor and / or in the caravan.

In addition to the electrical energy, the fuel cell unit also generates waste heat during operation, which can also be used in the tractor and / or caravan. For example, the waste heat can be used to heat the caravan or hot water. Alternatively or optionally, the (waste) heat can also be used in an absorption refrigeration machine (such as in a refrigerator, in particular a caravan refrigerator or an air conditioning system).

Pure hydrogen in an H2 tank can be used to operate the fuel cell unit. This can be stored in the hydrogen tank, for example, at a pressure of up to 700 bar. Alternatively or in addition to this, propane and / or butane can also be used as energy sources. This is widespread in the camping sector and is sold in gas bottles that are customary for camping. The propane and / or butane in gas bottles customary in camping has the advantage that the energy source, namely the gas bottle, can be easily exchanged. This easy-to-carry exchange of the gas cylinder can reliable supply of the fuel cell unit with the energy carrier can be ensured.

The need-based activation of the fuel cell unit results in the fact that mostly only one of the two forms of energy, namely electrical and thermal energy, is required and used immediately. If the fuel cell unit is now activated due to the presence of a heat requirement, this heat energy can be used (for example for heating / cooling and / or refrigerator). In addition to the thermal energy, however, electrical energy is also provided by the fuel cell unit, which is currently not used directly and is therefore present as excess electrical energy. This excess electrical energy can be stored in a high-voltage battery in the tractor and then made available to the caravan again if required. In addition to the examples mentioned, that is to say heating, cooling and / or refrigerator, the thermal energy provided by the fuel cell unit can also be used as heat for room heating in the caravan. This means that the thermal energy provided by the fuel cell unit is used to heat the interior of the caravan.

In another example, the fuel cell unit can be activated on the basis of the presence of a demand for electrical energy. The electrical energy made available by the fuel cell unit is then used directly, for example for light and / or stove, and thermal energy is also made available by the fuel cell unit. This thermal energy can now be regarded as excess thermal energy in accordance with the aforementioned electrical, excess energy. This means that this thermal energy is not used immediately after it has been provided by the fuel cell unit and it can therefore be used for further use. Such a further use can consist, for example, in the fact that the excess thermal energy is supplied to the refrigerator or an air conditioning system for heating water or in an absorption refrigeration system.

If the fuel cell is operated on the basis of an electrical energy requirement and too much thermal energy is generated in the process than can be stored, it is dissipated to the environment. If, on the other hand, the fuel cell is operated due to a heat requirement and too much electrical energy is made available than can be stored - for example because the batteries are fully charged - then the electrical energy is converted into heat by electrical heaters and thus used profitably, which then enables the fuel cell to operate can be reduced due to a heat requirement.

The idea according to the invention can also be integrated in a mobile home. In this case, the electrical and / or thermal coupling between the caravan and the tractor is omitted, since the components for the solution according to the invention are all integrated in one vehicle, namely the mobile home. The idea can also be applied to coaches or trucks that have an increased heat requirement.

Aspects of the invention are explained for the first time or in more detail below.

In a technical implementation, the fuel cell unit can be connected to the traction battery via an electrical supply line and optionally via a power distributor. In particular, the electrical supply line can be connected to the traction battery with the interposition of the voltage converter. This means that the electrical supply line can lead directly into the traction battery as well as into the traction battery via the voltage converter. The voltage converter can be a DC / DC converter (as a charger) or an AC / DC converter. For example, the AC / DC converter can be used as a charger when charging via a “commercial” AC socket. When charging the battery via direct voltage, the DC / DC converter can be used, which can in particular be accommodated in the caravan. The traction battery can act as an electrical energy store, in which the electrical energy provided as excess energy in the fuel cell unit can be stored. This has the advantage that the excess energy does not remain unused, but can be stored in the traction battery for later use. As a result, the energy provided by the fuel cell unit is used more efficiently.

Optionally, the fuel cell unit can be thermally connected to a thermal consumer via a thermal coupling. The thermal consumer can act as a thermal energy store, in which thermal energy can be stored as excess energy. This has the advantage that not only the electrical excess energy but also the thermal excess energy does not remain unused, but is instead fed to a further use, whereby the efficiency increases.

The thermal consumer can be the room heating / hot water preparation or an air conditioning system or an air conditioning unit, in particular an absorption refrigerator, in which a refrigerant is in a closed refrigerant circuit (possibly by means of a solution pump) is circulated. An evaporator, an expeller, a condenser and an absorber can be connected in the refrigerant circuit, wherein in particular the thermal energy can be fed to the expeller. This has the advantage that the thermal excess energy does not have to be converted unnecessarily often into other forms of energy, so that the thermal excess energy is used very efficiently. In these cases, the living space or the hot water tank or the interior / contents of the refrigerator act as storage.

In a technical implementation, a heat demand signal can be provided as the energy demand signal. The control unit can activate this heat demand signal when the heat demand signal is present, the fuel cell unit. In this case, for example, the fuel cell is operated in such a way that maximum thermal energy can be dissipated. The activation of the fuel cell assembly can take place with the provision of both thermal energy and electrical energy. In addition, the control unit can supply the thermal consumer, which has a heat requirement, with the thermal energy provided by the fuel cell assembly. The control unit can preferably store the electrical energy provided by the fuel cell unit as excess energy in the traction battery. As a result, the fuel cell unit is used even more efficiently, since it is activated as required based on the energy demand signal.

Alternatively or optionally, the energy demand signal can be an electricity demand signal. This power demand signal when the power demand signal is present, the control unit can activate the fuel cell assembly. In this case, for example, the fuel cell is operated in such a way that maximum electrical energy can be dissipated. The activation of the fuel cell assembly can take place with the provision of both thermal energy and electrical energy, and the control unit can supply the electrical consumer which has a power requirement with the electrical energy provided by the fuel cell assembly. The control unit can preferably supply the thermal energy provided by the fuel cell unit as excess energy to the thermal consumer, in particular its refrigerant circuit.

Particularly preferably, when an excessively large amount of thermal excess energy is present, part of the thermal excess energy can be dissipated to the environment. Alternatively or optionally, if there is an excessively large amount of excess electrical energy, part of the excess electrical energy can be converted into thermal energy in an electrical heater or, for example, by a cooling device into cooling energy, in order to reduce the heat requirement, thereby reducing the power output of the fuel cell is reduced due to the lower heat requirement. The power output of the fuel cell unit can be reduced in order to reduce the excess energy or to prevent its further provision, whereby the efficiency of the overall system can be increased.

In a technical implementation, the vehicle can have a tractor section and a residential section. The electric drive unit can be arranged in the tractor section. In the residential section, its electrical and thermal consumers can be supplied with energy from the auxiliary energy supply system.

The vehicle can preferably be implemented as a vehicle combination with a trailer or a mobile home.

A method for operating an electrically operated vehicle according to one of the preceding claims is particularly preferred.

In a technical implementation, the provided by the fuel cell unit. electrical energy can be used at least partially to operate external electrical consumers that are not housed in the tractor, in the caravan or in the motorhome. Such an external consumer can be an electric vehicle, which is charged by the provided electrical energy. Alternatively, it can also be an electrically operated tool or device. In addition, the electrically described vehicle can also be designed as a mobile emergency power unit, in particular in the form of an emergency power trailer, or it can be a truck or bus. The external, electrical consumer can be supplied with electrical energy from the fuel cell unit via a DC / AC converter.

According to the provided electrical energy, the thermal energy provided by the fuel cell unit can also be dissipated and used externally. For example, the thermal energy provided can be used to heat a tent.

Exemplary embodiments of the invention are described below with reference to the accompanying figures.

• 1 in einer Skizze ein erfindungsgemäßes, elektrisch betriebenes Fahrzeug aufweisend eine Zugmaschine und einen an die Zugmaschine angekoppelten Wohnanhänger;
• 2 in einem Blockschaltbild die Signal- und Energieströme in dem erfindungsgemäßen Fahrzeug;
• 3 in einem Blockschaltbild die Signal- und Energieströme in dem erfindungsgemäßen Fahrzeug bei Vorliegen eines Wärmebedarf-Signals;
• 4 in einem Blockschaltbild die Signal- und Energieströme in dem erfindungsgemäßen Fahrzeug bei Vorliegen eines Strombedarf-Signals;
• 5 in einer Skizze das erfindungsgemäße Fahrzeug in Form eins Wohnmobils.

Show it:

• 1 in a sketch of an electrically operated vehicle according to the invention having a tractor and a caravan coupled to the tractor;
• 2 in a block diagram the signal and energy flows in the vehicle according to the invention;
• 3 in a block diagram the signal and energy flows in the vehicle according to the invention when there is a heat demand signal;
• 4th in a block diagram the signal and energy flows in the vehicle according to the invention when there is a power demand signal;
• 5 in a sketch the vehicle according to the invention in the form of a mobile home.

In 1 is an electrically powered vehicle in the form of a vehicle combination 1 shown. The vehicle combination 1 has a tractor 3 - as a tractor section - and one with the tractor 3 coupled caravan 5 - as a residential section - on. In the tractor 3 an electric drive unit (not shown) is arranged and the tractor 3 exhibits a traction network T on, in which a traction battery 7th the electric drive unit of the tractor 3 with electrical energy E _el provided. That is, the traction network T is an electrical network that is primarily used to drive the tractor 3 serves. The traction network T has next to the electric drive unit and the traction battery 7th also a voltage converter 9 on, the electric with the traction battery 7th connected and charging and discharging the traction battery 7th undertakes.

In the trailer 5 is an auxiliary power supply system APU arranged, which via an electrical supply line 10 with the traction network T or the traction battery 7th or the voltage converter 9 the tractor 3 connected is. The auxiliary power supply system APU supplies electrical and thermal consumers with energy E _el , E _th . The auxiliary power supply system APU has a fuel cell unit FC on, which one with a hydrogen storage 14th is connected, the hydrogen as fuel for the fuel cell unit FC saves and delivers to this. The operated fuel cell unit FC provides independent of the traction network T for consumers thermal E _th and electrical energy E _el ready. The auxiliary power system APU has a control unit 19th on that via a signal line 15th signaling with the fuel cell unit FC is connected and when there is an energy demand signal S _W , S _l , the fuel cell unit FC activated. By activating the fuel cell unit FC become electrical consumers in the caravan 5 like a stove 21st or a refrigerator 23 with electrical energy E _el provided. At the same time or as an alternative, there are thermal consumers in the caravan 5 like the absorption chiller 23 a refrigerator or a space heater 25th with thermal energy E _th provided.

In 2 are the energy and signal flows within the traction network T and the auxiliary power system APU shown. The auxiliary power supply system APU points next to the fuel cell unit FC also a heat 31 and a power distributor 33 on that next to the fuel cell unit FC also for signaling via signal lines 32 , 34 with the control unit 19th are connected. The control unit 19th receives via an input unit 18th the energy demand signal S _W , S _l , and activates the fuel cell unit FC when this energy demand signal is present Sw , S _l . That is, the control unit 19th the fuel cell unit FC activated as required. After activating the fuel cell unit FC provides the fuel cell unit FC thermal E _th and electrical energy E _el ready. The electrical energy E _el is via an electrical supply line 36 into the power distributor 33 fed in and fed from there into the electrical consumers and / or energy storage. The fuel cell unit FC is also via a thermal coupling 24 with the thermal consumers 23 , 25th connected, which is why the fuel cell unit FC generated thermal energy E _th via a heat supply line 38 in the heat spreader 31 is fed in. The thermal coupling 24 with the thermal consumers 23 , 25th takes place in a closed circuit using a coolant, in particular a liquid, such as water. That means that to the thermal coupling 24 and to the heat supply line 38 a parallel return line is provided in each case (not shown), which returns the coolant, corresponding to a closed circuit. From the heat spreader 31 becomes the thermal energy E _th then fed into the thermal consumers, which act alternatively or additionally as thermal energy stores.

Used by the fuel cell unit FC If more thermal excess energy ΔE is provided than can be used by the thermal consumers or stored by the thermal energy stores, then the thermal excess energy ΔE is generated via a heat exchanger 30th dissipated to the environment. Used by the fuel cell unit FC If more electrical surplus energy ΔE is provided than can be used by the electrical consumers or stored by the electrical energy stores, the electrical Excess energy ΔE is converted into heat in an electrical heater and then possibly dissipated to the environment.

In 3 are the energy and signal flows within the traction network T and the auxiliary power system APU when there is a heat demand signal S _W shown. The heat demand signal S _W signals to the control unit 19th that one of the thermal consumers, namely a refrigerant circuit K the absorption chiller 23 and / or space heating 25th , Thermal energy E _th needed. Receives the control unit 19th the heat demand signal S _W so will the fuel cell unit FC activated, which gives it thermal energy E _th provides and the fuel cell unit FC this heat energy E _th via the heat spreader 31 feeds into the thermal loads and / or energy storage. At the same time, the fuel cell unit provides FC electrical power E _el ready. This electrical energy E _el is only available if the heat demand signal is present S _W not needed immediately. That is, this electrical energy E _el if only the heat demand signal is present S _W as excess energy ΔE. In order to put this excess energy ΔE to a meaningful use, the excess energy ΔE is in the form of electrical energy E _el in the traction battery 7th the tractor 3 stored and if necessary from the traction battery 7th into the electric drive unit of the tractor 3 fed in. That is, that in the traction battery 7th those in the fuel cell unit FC electrical energy provided as excess energy ΔE E _el is storable.

In 4th are the energy and signal flows within the traction network T and the auxiliary power system APU shown when there is a power demand signal S _l . The power demand signal S _l signals the control unit 19th that one of the electrical consumers, namely the stove 21st and / or another electrical consumer, electrical energy E _el needed. Receives the control unit 19th the power demand signal S _l , then the fuel cell unit FC activated, which makes it electrical energy E _el provides and the fuel cell unit FC this electrical energy E _el via the power distributor 33 feeds into the electrical consumers and / or energy storage. At the same time, the fuel cell unit provides FC thermal energy E _th ready. This thermal energy E _th is not immediately required when the power demand signal S _l is present alone. That is, this thermal energy E _th as excess energy ΔE. In order to put this excess energy ΔE to a meaningful use, the thermal excess energy ΔE is fed into the refrigerant circuit K the absorption chiller 23 and / or space heating 25th fed in. The refrigerant circuit K and / or space heating 25th thus not only serve as consumers, but also as energy stores for thermal energy E _th . That is, the excess thermal energy ΔE from the refrigerant circuit K and / or space heating 25th is recorded.

The refrigerant circuit K is part of a refrigeration device such as the absorption refrigeration machine 23 or an air conditioner. The refrigerant circuit K has, corresponding to an absorption refrigeration machine, a condenser 41 , an evaporator 43 , an absorber 44 and an expeller 47 on. In the closed refrigerant circuit K the refrigerant circulates and is in the evaporator 43 evaporates and to the absorber 44 forwarded. In the absorber 44 the refrigerant is absorbed by a solution. The solution enriched with refrigerant then becomes an expeller 47 promoted by separating the refrigerant from the solution while feeding in thermal energy. The one in the expeller 47 The thermal energy fed in is that from the fuel cell unit FC thermal energy provided E _th . After the separation, the refrigerant enters the condenser 41 conveyed and cooled there.

In 5 is a mobile home 51 shown. With this motorhome 51 are both the auxiliary power supply system APU as well as the traction network T in a single vehicle, namely the motorhome 51 , integrated. Otherwise, this electrically powered vehicle works in the form of the mobile home 51 in the same way as that in connection with the in the 1 to 4th vehicle combination described 1 the case is.

List of reference symbols

1

Vehicle combination

3

tractor

5

Caravans

7th

Traction battery

9

Voltage converter

10

supply line

14th

Hydrogen storage

15th

Signal line

18th

Input unit

19th

Control unit

21st

stove

23

Absorption chiller

24

thermal coupling

25th

Space heating

30th

Heat exchanger

31

Heat spreader

32, 34

Signal line

33

Power distributor

36

Electrical supply line

38

Heat supply line

41

capacitor

43

Evaporator

44

absorber

47

Expeller

51

Camper

T

Traction network

APU

Auxiliary power supply system

K

Refrigerant circulation

E _el

electrical power

E _th

thermal energy

S _W

Heat energy demand signal

S _E

Power demand signal

FC

Fuel cell unit

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102016217615 A1 [0004]

Claims (10)

Electrically operated vehicle with a traction network (T), in which a traction battery (7) supplies an electric drive unit of the vehicle with electrical energy (E _el ), and with an auxiliary power supply system (APU) with a fuel cell unit (FC) that is independent of the traction network ( T) provides electrical energy (E _el ) and thermal energy (E _th ) for consumers, the auxiliary energy supply system (APU) having a control unit (19) which, when an energy demand signal (Sw, S _l ) is present, the fuel cell unit (FC) activated, when activated at least one electrical consumer (21) can be supplied with electrical energy (E _el ) and / or at least one thermal consumer (23) can be supplied with thermal energy (E _th ), characterized in that the vehicle is thermal and electrical Has energy store (7, 25), and that a provided during activation of the fuel cell assembly (FC), not for d The energy supply of the consumer required excess energy (ΔE) in the form of electrical energy (E _el ) or thermal energy (E _th ) can be stored in the electrical or thermal energy store (7, 25). Electrically powered vehicle after Claim 1 , characterized in that the fuel cell unit (FC) is connected to the traction battery (7) via an electrical supply line (10), and that the traction battery (7) acts as an electrical energy store, in which the in the fuel cell unit (FC) as excess Energy (ΔE) provided electrical energy (E _el ) can be stored. Electrically powered vehicle after Claim 1 or 2 , characterized in that the fuel cell unit (FC) is thermally connected to the thermal consumer via a thermal coupling (24), and that the thermal consumer (23) acts as a thermal energy store in which thermal energy (E _th ) is used as excess energy (ΔE) can be stored. Electrically powered vehicle after Claim 3 , characterized in that the thermal consumer (23) is an air conditioning system or a refrigeration device, in particular an absorption refrigeration machine, in which a refrigerant circulates in a closed refrigerant circuit (K), an evaporator (43), an expeller, in the refrigerant circuit (K) (47), a capacitor (41) and an absorber (44) are connected, and that in particular the thermal energy (E _th ) can be fed to the expeller (47). Electrically operated vehicle according to one of the preceding claims, characterized in that the energy demand signal is a heat demand signal (S _W ), that the control unit (19) activates the fuel cell unit (FC) when the heat demand signal (S _W ) is present, while providing both thermal energy (E _th ) and electrical energy (E _e ), and that the control unit supplies the thermal consumer (23) with a heat requirement with the thermal energy (E _th ) provided by the fuel cell unit (FC) supplies, and that in particular the control unit (19) stores the electrical energy (E _el ) provided by the fuel cell unit (FC) as excess energy (ΔE) in the traction battery (7). Electrically operated vehicle according to one of the preceding claims, characterized in that the energy demand signal is an electricity demand signal (S _l ), that the control unit (19) activates the fuel cell unit (FC) when the electricity demand signal (S _l ) is present, while providing both thermal energy (E _th ) and electrical energy (E _el ), and that the control unit (19) supplies the electrical consumer (21) with a power requirement with the electrical energy (E _el ), and in particular the control unit (19) supplies the thermal energy (E _th ) provided by the fuel cell unit (FC) as excess energy (ΔE) to the thermal consumer (23), in particular its refrigerant circuit (K). Electrically powered vehicle after Claim 6 , characterized in that when there is an excessively large amount of thermal excess energy (ΔE), part of the thermal excess energy (ΔE) can be dissipated to the environment, and / or that when an excessively large amount of electrical excess energy is present (ΔE) a part of the electrical surplus energy (ΔE) in an electrical heater can be converted into thermal energy in order to lower the heat demand, whereby the power output of the fuel cell is reduced due to the lower heat demand. Electrically operated vehicle according to one of the preceding claims, characterized in that the vehicle has a tractor section (3), in which the electric drive unit is arranged, and a residential section (5) whose electrical and thermal loads are from the auxiliary power supply system (APU ) can be supplied with energy (E _el , Eth). Electrically powered vehicle after Claim 8 , characterized in that the vehicle is implemented as a vehicle combination (1) with a trailer (5) or as a mobile home (51). Method for operating an electrically powered vehicle according to one of the preceding claims.

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