WO2018138424A1

WO2018138424A1 - Land-based utility vehicle with electrical propulsion and multiple power sources

Info

Publication number: WO2018138424A1
Application number: PCT/FR2018/050043
Authority: WO
Inventors: Roger Pellenc
Original assignee: Pellenc
Priority date: 2017-01-24
Filing date: 2018-01-09
Publication date: 2018-08-02
Also published as: FR3062094A1; FR3062094B1

Abstract

The invention concerns a land-based utility vehicle (10) with electric propulsion comprising: - at least one electric propulsion motor (24) and - at least one main power source (20) supplying power to the vehicle, comprising a storage battery (21), - at least one auxiliary power source (40) supplying power to the vehicle, separate from the main power source (20), the auxiliary power source supplying power to the vehicle being a removable source, configured so as to be selectively fitted on the vehicle or removed from the vehicle, depending on a power requirement of the vehicle. The invention is applicable to agricultural tractors, vineyard tractors and public works vehicles.

Description

Land Utility Vehicle with Electric Propulsion and Multiple Power Supplies

Technical area

The present invention relates to a land-based utility vehicle with electric propulsion and multiple power sources. It is considered that the vehicle is electrically propelled when equipped with one or more electric motors used for the movement of the vehicle. Electric motors can in particular be coupled to wheels or tracks of the vehicle. Furthermore, it is considered that the vehicle is at multiple power sources when it is likely to have, permanently or not, more than one power source for its operation or for the operation of its accessories or apparatus.

The invention finds applications particularly in the agricultural field, or vitloola, for electric tractors, as well as for public works, forestry or roads. State of the prior art.

A state of the art is illustrated by oversold documents relating to vehicles or electric tractors:

FR 2 943 608

US 4662,472

US 6,573,675

US 7488,587.

Tractors, and more generally commercial vehicles, are generally heavy vehicles, of several hundred kilograms. They are used alone when they are dedicated to a single function, for example a road cleaning vehicle, or combined with specialized complementary equipment, for example, a tractor associated with a trailer, a towed harvesting machine, a agricultural sprayer However, in view of the power required for these vehicles, which may be associated with equipment, and particularly for tractors used in the agricultural field, the mass and cost of the batteries may prove prohibitive to ensure the autonomy of the vehicle. during a full day's work.

DISCLOSURE OF THE INVENTION The invention proceeds from the observation that the energy, and by extension the power required for the operation of commercial vehicles, and in particular agricultural or wine-growing tractors, is very variable depending on their use. While limited power may be sufficient for use of the vehicle in a single trip, or for the use of energy-efficient equipment such as towing a light trailer, much more power may be required when work, or work involving equipment or accessories with high energy consumption driven and driven by PTO of the vehicle.

Such electric-powered utility vehicles would thus be used most of the time with relatively low energy requirements for several hours, and could therefore be powered by a lighter, less bulky and much less expensive battery to cover these needs,

The invention thus aims to provide an electric vehicle adaptable in terms of power supply, depending on the workload for which it is intended.

To achieve this goal, the invention proposes an electric propulsion utility land vehicle comprising:

- at least one electric propulsion motor and

at least one main source of power supply of the vehicle comprising a storage battery,

- at least one auxiliary power source of the vehicle, separate from the main source of power supply, the auxiliary source power supply of the vehicle being a removable source, configured to be selectively put in place on the vehicle or removed from the vehicle, depending on the energy requirement of the vehicle, and

- An electric distribution bus, the main power source and the propulsion electric motor being connected to the electrical distribution bue.

According to the invention the vehicle further comprises at least one of an electric power take-off, and a hydraulic pump with an electric motor connected to the electrical distribution bus.

Electric power take-off means either an electrical connector to which accessory equipment may be connected, or a mechanical power take-off driven by an electric motor. These equipments are intended for the supply of electrical, mechanical or hydraulic energy of accessory equipment of the vehicle, such as hydrostatic lifting equipment, plowing equipment, vine treatment equipment or plantations, or equipment public works equipped with actuators. The main source of power supply comprises a storage battery preferably installed permanently in the vehicle. This battery can be recharged if necessary, and held at an electric charging station, for example when the vehicle is stored. It was considered that the main source of power supply is intended for the power supply of the vehicle when it is used in particular for powering the electric propulsion motor (s) of the vehicle. Eite can be used further for the power supply of other electrical equipment of the vehicle such as electric, mechanical or hydraulic power take-offs.

The main power source of the vehicle can be conflgurôe to allow the supply of the vehicle, and associated equipment, under any circumstances, so that the only main source of power is sufficient for the use of the vehicle, autonomously . The auxiliary power source of the vehicle is not permanently installed in the vehicle but is removable. It is considered that the auxiliary power supply source is removable when it can be easily and quickly removed and disconnected from the vehicle, or on the contrary put in place and connected quickly, without additional adaptation of the vehicle, and to the monk so quickly the adaptation of equipment to the vehicle.

In particular, the auxiliary supply source may be configured for placement or withdrawal, by means of quick fixing means, such as hooks, or manual tool-less fixing brackets.

The removable nature of the auxiliary source of power supply makes it possible to adapt the vehicle according to a need for energy, for a longer period of operation of the most important vehicle, for example, and makes it possible to considerably lighten the main source of power. intended to stay on the vehicle. In particular, the main source of power supply may be equipped with a storage battery whose electrical capacity and weight are much lower than those which would be required in the absence of the possibility of setting up the auxiliary power source. power supply. When the vehicle is to be used for a light task, not very energetic, typically for the simple movement of its user or to tow a light trailer, the main source alone, although limited electrical capacity, has sufficient autonomy, for example at least half a day of work.

Similarly, when the vehicle is to be used for a heavy and energetic task, but of short duration, for example of the order of one hour, the main source alone may also have sufficient autonomy.

In these cases the vehicle is preferably not equipped with the accessory power supply source.

It turns out that under these conditions, that is to say without auxiliary power supply the electric vehicle can generally cover most of the needs of the user during a year of work. For a winemaker, for example, it results in a light tractor, at a reasonable cost, cause less compaction of the silk of its passage in the vines, while not polluting the vines and working without significant noise.

On the other hand, when the vehicle is to be used for a heavy and energy-consuming task, or when a great autonomy of use is required, it can if necessary be equipped with the auxiliary power source.

In this case, the auxiliary power supply source of the vehicle, embarked on the vehicle, can supply energy needs, to supply the propulsion motor (s), to supply the electrical equipment and vehicle power take-offs, or even to recharge fa battery of the main power source.

The main purpose of the electrical distribution bus is to distribute electrical energy from the main power source to the electric propulsion motor (s) and the electric power take-off (s), or to the hydraulic pump. Energy can also be transported, via the electrical distribution valve, from the electric propulsion motors to the main power source, this being the case in a mode of operation with energy recovery, during a deceleration of the vehicle, for example.

The auxiliary source of power supply can also participate in the supply of the electrical energy required by the various electric motors or power take-offs of the vehicle. It can be connected in parallel with the main power source. In this respect, and advantageously, the vehicle may further comprise a connector for the auxiliary power supply source, the connector being connected to the electrical distribution bus. In this case, exchanges of electrical energy may also have been made from and to the auxiliary power supply source via the electric distribution bus,

By way of example, the electric distribution bus can supply the electric propulsion engines of the vehicle from the battery of accumulators of the main source of power and / or from the auxiliary power supply when present.

The electrical distribution bus can also be used, as indicated above, to charge the storage battery of the main power source with an electric current produced by the electric propulsion engines used as generators. vehicle.

Finally, the electrical distribution bus can supply the storage battery of the main power source to recharge it with current from the auxiliary power supply source, especially if the electrical power produced by the auxiliary power source power supply temporarily exceeds the needs of the vehicle.

Different types of auxiliary sources of power supply can be envisaged. In particular the auxiliary power supply source may comprise a fuel wafer, for example a hydrogen or alcohol (methanol, éthartoi) battery, an electric storage battery, or an independent generator with a thermal engine. These different solutions are not exclusive of each other. Indeed, several auxiliary sources can be provided and intended for the vehicle,

The use of a stand-alone generator with an internal combustion engine as an auxiliary source of electrical power makes it possible to considerably increase the range of the vehicle for reduced pollutant emissions and cost. This is, for example, a thermal engine group powered by gasoline, diesel, natural gas or ethanol, depending on the fuel most used in the country concerned by the use of the vehicle. . The autonomy of the generator is ensured in particular by the amount of fuel contained in a fuel tank Integrated with the generator and by the presence of a starting device. Moreover, the heat engine may preferably be a constant speed engine, so as to limit its consumption and its emissions of polluting gases.

The use of a generator as a power source has other advantages. It allows, for example, to recharge the storage batteries of the main power source, in the case of a temporary or permanent impossibility of connection or access to an electrical distribution network.

As with other auxiliary sources, a generator also makes it possible to cope with a momentary demand for increased power under severe conditions of use of the commercial vehicle. Finally, the generator can be used as needed as an independent power source for tools independent of the vehicle.

The function of the electrical distribution bus is, as indicated above, to distribute the electrical energy according to the instantaneous energy needs of the vehicle and according to the available power sources.

According to an advantageous implementation of the invention, the vehicle may comprise a bidirectional voltage converter connecting the main source of electrical power supply to the electrical distribution bus. The use of a voltage converter makes it possible to make the operating voltage of the electrical distribution valve and the voltage of the main source of electrical power independent.

Thus, and in particular, the power distribution bus may have a bus voltage greater than a maximum charge voltage of the storage battery of the main power source.

The auxiliary power supply, as well as electric motors, or electric power take-offs, can also be connected to the electrical distribution bus via voltage converters, so as to make the operating voltage of each of these organs.

Preferably, the electrical distribution bus of the vehicle is configured to maintain a high voltage threshold, greater than 300 volts, and, for example, a voltage threshold of 450 volts, and comprises power components capable of maintaining this threshold. Of voltage. Maintaining a high voltage limits current Intensity Issus or to the equipment connected to the power distribution bus, given the power transmitted through the power distribution bus. The voltage converter or converters used, and in particular the voltage converter associated with the main power supply source, are preferably bidirectional, ie configured for powering the electrical distribution bus from the battery. accumulators of the main source of power supply and, conversely, for the charging of the storage battery of the main power supply source from the electric distribution bus,

As mentioned above, the auxiliary power supply source may also comprise a voltage converter, it may be in particular an internal voltage converter, that is to say a converter of its own, in order to adapt the voltage of the auxiliary power supply source to that of the electric distribution bus. This makes it easier to connect the auxiliary power supply source to the electrical distribution bus when it is put in place on the vehicle.

The vehicle may comprise a plurality of electric propulsion motors connected respectively to a plurality of driving wheels, it may also be equipped with tracks.

One of the possibilities mentioned above, and consisting in equipping the vehicle with an auxiliary power source in the form of a storage battery, also provides advantages in terms of cost and depreciation of the cost of the vehicle . In the battery market there is indeed a general tendency to increase the electrical capacitance and to reduce the cost over time. The advent of cheaper and more efficient batteries is therefore predictable. Thus, the vehicle can initially be provided with a main power source in the form of a battery of accumulators of limited capacity and cost, associated if necessary with an auxiliary power source of the electrogenerating group type, to reduce its influence on the price of the vehicle. Such a vehicle then allows a subsequent evoiutfon at lower cost, in terms of capacity and autonomy, but also in terms of reducing polluting emissions and noise, Greek to a new battery pack, cheaper, and used as an auxiliary power supply source within the meaning of the invention. Such an evolution does not require any dismantling or any workshop intervention on the vehicle. Advantageously, the vehicle of the invention can be associated with an electric battery charger. The electric charger is for recharging an electric storage battery equipping at least one of the main power source and the auxiliary power source. The electric charger can be integrated in an autonomous electric charging station, remote from the vehicle, but preferably dedicated to the vehicle. In this case, the battery of the main power source can be exchanged when the vehicle is near the loading station. The loading station is located, for example, in a shed for the vehicle. When the vehicle is equipped with an auxiliary power supply with an electric battery, it can be loaded by the charging station's charger.

According to another possibility, which is not exclusive of the previous one, the electric charger can be integrated into the vehicle. In this case the batteries of the main source of power supply, and if necessary the battery of the auxiliary power supply source can be recharged by the charger connected to any socket of a domestic electrical distribution network or Industrial.

At least one of the storage battery of the main power source, and the storage battery of the auxiliary power source may be provided with a battery management unit configured to control the charge and the discharge of the storage battery, as well as the balancing of the cells of the storage battery.

As previously indicated, the vehicle may be an agricultural tractor, a viticultural tractor or a public works machine. Other features and advantages of the invention appearing from the description which follows, with reference to the figures of the drawings. This description is given as an illustration and not as a limitation

Brief description of the figurines

Figure 1 is a schematic perspective view of an agricultural tractor in a configuration without an auxiliary power supply source. Figure 2 is a partial exploded view of the agricultural tractor of Figure 1.

Fig. 3 is a schematic perspective view of an agricultural tractor in a configuration with an auxiliary power source in the form of a fuel hoop or an electric battery of accumulators.

Figure 4 is a partial exploded view of the agricultural tractor of Figure 2.

Figure 5 is a partial and schematic exploded view of an agricultural tractor in a configuration with an auxiliary power supply source in the form of a thermal engine generator set. Figure 6 is a schematic and synoptic representation of the main electrical components of a vehicle according to the invention and illustrates their mutual connection.

The figures are executed in free scale. DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Identical, similar or equivalent parts of the different figures are indicated with the same numerical references so as to be able to refer from one figure to another. Figure 1 shows an agricultural tractor 10 provided with four driving wheels

12. The tractor further comprises a control cabin 14, and a main power source 20 comprising an electric storage battery 21, represented here symbolically. Due to the weight of the battery, it is arranged in a low position, partly under the cabin 14, so as to ensure good stability of the tractor.

The portion of the main power source 20 protruding from the cabin is covered with a cover 22.

FIG. 2 shows, in the form of an exploded view, electric motors for propulsion 24 of the wheels, provided with reducers and respectively associated with each of the wheels of the tractor 10. The wheels are thus each driven. Each electric motor 24 has for example a nominal power of 25kW, and a peak power of 50kW. Such motors associated with mechanical gearboxes with a ratio of 1/50 allow transmission without a gearbox at speeds of about 0 to 40 km / h.

In Figure 2, the hood 22 is removed from the tractor. Its withdrawal reveals a connector 26. The connector 26, in the form of a fixed base, comprises power connection terminals and control signal transmission terminals. The function of the connector 26 is described below.

The accumulator battery 21 of the main power supply source 20 is symbolically represented. This is, for example a battery of type llihfunvlon with an energy of 20kWh or more, delivering a voltage of 300 volts,

Figure 3 shows the tractor 10 on which the hood 22 is replaced by an auxiliary power source 40. The auxiliary source of power supply is an electromagnetic source provided with an accumulator battery 42 and / or a fuel hull 44 indicated symbolically.

A voltage converter 46 for adjusting the voltage of the auxiliary power supply source 40 to the nominal operating voltage of the tractor is also symbolically indicated. These elements are contained in a bodied casing 48 fixed to the tractor by quick fastening means not shown.

FIG. 4 shows, in the form of an exploded view, that the auxiliary supply source 40 is also provided with a connector 27. When the auxiliary power source 40 is placed on the tractor, In place of the hood 22, the connector 27 of the auxiliary source is coupled with the connector 26 of the tractor, to establish an electrical connection between the auxiliary power supply and the tractor. The electrical connection may include a power connection and a signal connection. This aspect is described later.

FIG. 5 schematically shows, in the form of an exploded view, a particularly advantageous embodiment of the tractor in which the auxiliary power source 40 comprises a generator 50.

The main members of the generator are a heat engine 52 of which only an exhaust pipe is visible, an alternator 94, driven by the heat engine 52, and a fuel tank 56. These bodies are represented symbolically.

The heat engine 52 is, for example, a three-cylinder 35-50kW motor whose rotational speed is adjusted to 3000 rpm. This is preferably a fixed rotational speed corresponding to the maximum efficiency of the engine. The generator set 50 may comprise other organs that are not shown, such as:

a mechanical multiplier making it possible to increase the rotational speed of the alternator with respect to the speed of rotation of the heat engine. The multiplier makes it possible, for example, to turn the alternator 54 at a speed of 8000 rpm for a speed of rotation of the heat engine 52 of 3000 revolutions per minute,

a rectifier and a filter of the alternating voltage produced by the alternator to make a DC voltage,

a possible voltage converter for adapting the output voltage of the generator set to a nominal operating voltage of an electrical distribution bus of the tractor, described below,

a radiator for cooling the heat engine,

- an electric starter provided with a battery autonomous propm starter.

- an electronic control unit. The control box can then be connected to a vehicle calculation and control unit. This aspect is described in more detail in the following description.

Incidentally, the generator may include a connection interface for connecting household or industrial electrical appliances other than the tractor, when it does not equip the tractor or when it is loaded on the tractor stationary. The generator can thus also serve as general purpose power supply. The elements of the generator set 50 are housed in a bodied casing

48, which can be attached to the tractor in a manner comparable to the body housing 48 of Figure 3. It is fixed by quick fastening means, not shown. When the generator group 50 is put in place on the tractor, it is also electrically connected to the tractor by means of a connector 27, which engages with the connector 26 of the tractor. Lee connectors 28, 27 have several functions. A main function is to connect the auxiliary supply source 40 to the tractor 10 and in particular to an electric distribution bus of the tractor. Another function is to allow the bidirectional transmission of control and control signals between the tractor and the auxiliary power source 40. It should be noted, however, that the connectors can be split to separate the control signals and the power transmission.

In the case of an auxiliary power source 40 in the form of a generator set 50, it can be driven according to the charge or the voltage of the storage battery 21 of the main source 20 tractor power supply. For example, when the voltage of the battery 21 reaches a predetermined low threshold, a control signal can be directed to the generator 50 to trigger the automatic start of the engine 52. Conversely, when the voltage of the battery 21 reaches a predetermined high threshold, a control signal can be directed to the generator 50 to stop the heat engine 52.

FIG. 8 schematically and simplifiedly illustrates a possibility of connection of the main electrical components of the tractor 10.

The electrical architecture of the tractor is organized around an electrical distribution bus 60. This is, for example, a DC bus under a voltage of 450 volts. The electrical distribution bus 60 is connected to the electric motors 24 for propelling the tractor 10. It is also connected to an electric front PTO motor 62, an electric rear PTO motor 64, and a drive motor 66. a hydraulic pump. Other unrepresented electrical consumers, such as, for example, an electric power take-off for tractor accessories, tractor light bulbs, windscreen wipers, an air-conditioning system or electronic components of a unit control, can also be powered directly or indirectly via the bus 60 of electrical distribution. If necessary, voltage converters may be provided to adapt the bus voltage 60 to the nominal voltage of the motors and electrical equipment mentioned above. The electrical distribution bus 60 is electrically connected to the battery 21 of the main power supply source also via a bidirectional voltage converter 23 to adapt the voltage of the battery 21 to that of the bus 60.

The bus is finally electrically connected to the connector 26 of the tractor.

When no auxiliary power supply is provided to the tractor, power is supplied from the single main source of power. Electrical energy is distributed to the motors and other electrical consumers via the power distribution bus 60.

When the electric propulsion motors 24 are engines operating in a generator mode during braking phases of the tractor, these can also provide a charging current of the battery 21 of the main power source 20, This is the case in particular when the propulsion electric motors 24 are DC motors, brushless, and electronically controlled.

As indicated above, the electrical connector 26 of the tractor is also connected to the power distribution bus 80. Thus, when an auxiliary power source 40 is placed on the tractor and connected to the connector 26 of the tractor, the auxiliary power source 40 is electrically connected to the power distribution bus 60. In this case, the electric propulsion motors 24 and the other electrical consumers 62, 64, 66 mentioned above can be directly supplied by the only auxiliary power source 40, or concomitantly with the main source and the auxiliary source.

In addition, if the energy that can be supplied by the auxiliary power supply source 40 exceeds the energy consumed by the electric motors and accessories of the tractor, the auxiliary power supply source 40 also enables the battery 21 to be recharged. of the main power source 20 via the power distribution bus 60.

Reference 70, symbolically indicates a computing and control unit, also connected to the electrical connector 26 of the tractor. This unit allows to transmit control signals to the auxiliary power source 40, according to the operating parameters of the tractor, and in particular according to a state of charge of the storage battery 21 of the main source 20 power supply. The calculation and command unit comprises a communication bus 72 indicated in broken lines, such as, for example, a bus with CAN communication protocol. The communication bus 72 is connected to the different members connected to the electrical distribution bus 60, as well as to sensors, not shown. The computing and control unit thus makes it possible to control and control the vehicle and the various members connected to the electrical distribution bus 60. Finally, the computing and control unit is connected to a man / machine interface 74 located in the cab of the vehicle to control and direct the vehicle.

The computing and control unit 70 can also collect via the connector 26, monitoring signals and operating signals from the auxiliary power source 40, it may be, for example, signals from a battery management unit indicative of a state of charge of an electric battery of the auxiliary power supply source 40, if so provided. It may also be signals of an electronic unit, indicative of a state of operation of a generator when such a group equips the auxiliary power source 40. The signals can in this case indicate, for example, a fuel level in a fuel tank of the generator set.

Additionally, when the auxiliary power supply source comprises a fuel cell, the computing and control unit 70 can collect signals indicative of a fuel level of the fuel cell.

As shown in FIG. 6, the calculation and control unit 70 of the tractor is connected to the auxiliary power supply source 40 via the connectors 26, 27 and the communication bus 72. This makes it possible to connect automatically the computing and control unit 70 to an electronic control unit or a management unit of the auxiliary power source, when the auxiliary source 40 is connected to the tractor 40. In Fig. 6 a dashed line indicates the accessory and optional character of the auxiliary power source 40.

When the tractor is out of service, for example when it is stored, a battery charger, not shown, can be connected to the electrical distribution bus 60 via the connector 26 or via another dedicated connector . The battery charger is in no way an auxiliary power source of the tractor within the meaning of the invention insofar as it does not intervene in the power supply of the engines. The battery charger is used to recharge the battery 21 of the main power source 20, or to maintain it in charge.

Similarly, the same charger can be connected to the auxiliary power source, either directly through the tractor's power distribution bus, when the auxiliary power supply is provided with a power supply. storage battery. In this case, the charger can also be used to charge and maintain the charge of the accumulator battery of the auxiliary power source. A charger on the tractor can also be provided for recharging the batteries of the main source or the auxiliary source, by simply connecting to a home or industrial electrical distribution network.

Claims

claims

1) Utility electric land vehicle (10) comprising:

- at least one electric propulsion motor (24)

at least one main source (20) for powering the vehicle comprising an accumulator battery (21),

An auxiliary power supply source (40) for the vehicle, separate from the main power source (20), is provided, the auxiliary power source of the vehicle being a removable source configured to be selectively installed. on the vehicle or removed from the vehicle, depending on the energy requirement of the vehicle, and

an electric distribution bus (60), the main power supply source (20) and the electric propulsion motor (24) being connected to the electrical distribution bus (60),

characterized in that it further comprises at least one of an electric power takeoff (62, 64), and an electric motor hydraulic pump (66), connected to the power distribution bus (60). 2) Vehicle according to claim 1, further comprising a connector

(26) for the auxiliary power source (40), the connector being connected to the power distribution bus (60).

3) Vehicle according to claim 1 or 2, comprising a bidirectional voltage converter (23) connecting the main power source (20) of the power supply to the bus (60) of electrical distribution.

4) Vehicle according to claim 3, wherein the bus (60) of electrical distribution has a bus voltage greater than a maximum charging voltage of the storage battery of the main source.

5) Vehicle according to claim 1, wherein the auxiliary power source (40) comprises a self-generating electrogenetic group (50) with a heat engine (52). 6) Vehicle according to claim 1, wherein the auxiliary power source (40) comprises an electric storage battery (42).

The vehicle of claim 1, wherein the auxiliary power source (40) comprises an autonomous fuel cell (44).

A vehicle according to any one of the preceding claims, wherein the auxiliary power source (20) comprises a voltage converter (46).

9. Vehicle according to any one of the preceding claims, comprising a plurality of electric propulsion motors (24) respectively connected to a plurality of drive wheels (12).

10) A vehicle according to any one of the preceding claims characterized in that the vehicle is one of an agricultural tracer, a tractor and a vlticole public works machine.

11) Vehicle according to any one of the preceding claims, associated with an electric battery charger, for recharging an electric accumulator battery equipping at least one of the main power source and the auxiliary source. power supply.

12) Vehicle according to claim 11, wherein the electric charger is integrated in an electric charging station remote from the vehicle.

13) Vehicle according to claim 11, wherein the electric charger is integrated with the vehicle.

14) Vehicle according to claim 6, wherein at least one of the storage battery (21) of the main power source, and the accumulator battery (42) of the auxiliary power supply source is equipped with a battery management unit configured to control the charging and discharging of the storage battery, and the balancing of the cells of the storage battery.