DE102020120015A1 - Motor vehicle, system and method for charging a traction battery - Google Patents

Abstract

The invention relates to a system, a method for charging a traction battery and a motor vehicle (12). The motor vehicle (12) has a fuel tank (16) for a fuel cell (18) and a traction battery (20), the fuel tank (16) having a secondary coil device (24) which is designed to generate a current by electromagnetic induction and to charge the traction battery (20) with the current.

Description

The invention relates to a motor vehicle with a fuel tank for a fuel cell and with a traction battery, a system with a ground-side primary coil device and a motor vehicle, and a method for charging a traction battery.

Currently, a motor vehicle with a fuel cell, which can also be referred to as a fuel cell vehicle, is usually designed in such a way that, in addition to a fuel tank, there is also a battery-electric energy source, i.e. a high-voltage battery or traction battery, in order to implement various operating strategies and drive concepts. The traction battery can preferably also be charged externally via a separate charging connection or by means of induction coils.

A fuel tank, such as a hydrogen tank, is primarily located on an underside of the automobile. An inductive charging system for charging the traction battery can also be arranged on the underside of the motor vehicle. In this case, energy is transmitted contactlessly via a primary coil on the ground to a secondary coil in the motor vehicle, with the induced energy then being able to be stored in the traction battery.

The disadvantage of a motor vehicle with a fuel tank and an inductive charging system is that this configuration requires a lot of space on the underside of the motor vehicle, making it difficult to align the primary coil with the secondary coil.

From the DE 10 2015 201 788 A1 there is known a generic tank for safely storing a fuel in a high-pressure gas state and a method of manufacturing the same. The gaseous fuel storage tank includes a composite material forming a tank shell and a liner disposed beneath the composite material. In addition, the liner has a structure in which a metal coil is formed integrally with the liner.

From the DE 10 2017 205 436 A1 a method for operating a superconducting magnetic energy store and a motor vehicle with a superconducting magnetic energy store are known.

From the FR 3 030 387 A1 an electrically driven traction system with a hydrogen tank for a vehicle is known. The vehicle has an electrical machine that is used to generate electrical energy during generator operation, with the electrical energy being stored in a superconducting coil that is arranged in the hydrogen tank.

The object of the invention is to make it easier to charge a traction battery.

This object is solved by the independent patent claims. Advantageous developments of the invention are disclosed by the dependent claims, the present description and the figures.

The invention is based on the finding that a combination of a secondary coil device with a fuel tank saves space and the secondary coil device is therefore easier to reach for inductive charging, which makes it easier to charge a traction battery by means of electromagnetic induction.

The invention relates to a motor vehicle with a fuel tank for a fuel cell and with a traction battery, the fuel tank having a secondary coil device which is designed to generate a current through electromagnetic induction and to charge the traction battery with the current. In other words, the secondary coil device is arranged in or on the fuel tank. Preferably, the secondary coil device may have an electronic connection to the traction battery, which may be located outside the fuel tank in the motor vehicle. The secondary coil device can have one or more secondary coils, each of which is designed to induce a current or a voltage when introduced into an alternating electromagnetic field and thus to charge the traction battery. The fuel tank for the fuel cell can in particular include a fuel such as hydrogen, methanol, butane or natural gas. The advantage of the invention is that space requirements in the motor vehicle can be reduced, in particular on the underside of the motor vehicle, as a result of which the secondary coil device is more easily accessible and charging the traction battery is facilitated as a result. Furthermore, the arrangement of the secondary coil device on or in the fuel tank enables better dissipation of heat, which can arise during an inductive charging process, via the fuel tank to a chassis of the motor vehicle. Also, since a separate component is no longer required for the secondary coil device, the weight of the motor vehicle can also be reduced, since separate coil receptacles and fastening means do not have to be provided.

The invention also includes embodiments that result in additional advantages.

An embodiment provides that the secondary coil device is arranged in a wall of the fuel tank or on an outside of the fuel tank. In other words, the secondary coil device is not located in the fuel of the fuel tank but in the wall surrounding the fuel tank or on an outside of the wall. The wall of the fuel tank can, for example, have a multi-layer design, with one layer being able to comprise the secondary coil device, in particular a secondary coil of the secondary coil device. This embodiment has the advantage that the secondary coil device is easily accessible and a charging process can therefore take place in a simplified manner. Furthermore, heat that may be generated in charging can be easily dissipated through the outside or the wall of the fuel tank.

Provision is preferably made for the secondary coil device to be aligned essentially in the direction of an underside of the motor vehicle. That is, the secondary coil device faces down toward a road surface or a ground. This results in the advantage that the secondary coil device can be easily reached from below and can be loaded, for example, from a primary coil on the bottom.

Provision is also advantageously made for the secondary coil device to be adapted to a shape of the fuel tank. In other words, the fuel tank and the secondary coil device form a unit, with the secondary coil device abutting against a periphery of the fuel tank. The fuel tank can, for example, have a cuboid, oval, spherical or cylindrical shape and the secondary coil device can fit or be adapted to a straight, curved, angular and round shape of the fuel tank. Preferably, the secondary coil device may be fitted to a side face of the shape of the fuel tank. This means that the secondary coil device can be adapted to a lateral surface of the cylinder in the case of a cylindrical shape of the fuel tank. This results in the advantage that the secondary coil device at least partially has the shape of the fuel tank and no additional space is required in the motor vehicle.

One embodiment provides that the fuel tank is cylindrical with a substantially circular circumference and the secondary coil device is curved around the circular circumference. In other words, the secondary coil device is at least partially curved around a lateral surface of the cylindrical fuel tank. This embodiment has the advantage that the secondary coil device can be adapted to a cylindrical fuel tank with a small space requirement.

It is preferably provided that the secondary coil device is arranged with a center angle between 45 degrees and 180 degrees around the circular periphery of the fuel tank. In other words, the secondary coil device may be arranged in a lower half circumference of the cylindrical fuel tank, or at least fitted to an eighth of the circumference. This arrangement results in the advantage that an advantageous ratio can be established between an area through which an inductive energy transmission can take place and the accessibility of the secondary coil device.

A further embodiment provides that the secondary coil device has a plurality of secondary induction coils, the secondary induction coils being arranged in such a way that a respective area vector of the respective secondary induction coils is aligned perpendicular to the outside of the fuel tank. In other words, the respective secondary induction coils are arranged concentrically. This embodiment results in the advantage that a magnetic flux can enter a respective secondary induction coil from a primary coil device of complementary design, and energy can be transmitted more efficiently as a result.

According to the invention, a system is also provided with a ground-side primary coil device and a motor vehicle according to one of the preceding embodiments, the primary coil device having at least one primary induction coil and a movement device which is arranged on a carrier device, the primary induction coil having a shape adapted to the fuel tank, the Movement device is designed to move the primary induction coil between a first and a second state, wherein in the first state the primary induction coil is retracted onto or into the carrier device and in the second state the primary induction coil is extended for inductive energy transmission to the secondary coil device. In other words, a bottom primary coil device is provided, which includes a support device, a movement device device and has a primary induction coil, wherein the primary induction coil can be retracted by a movement device on or in the carrier device. Furthermore, the primary induction coil can be extended to the secondary coil device by the movement device, the primary induction coil representing the counterpart to the shape of the secondary coil device. This results in the advantage that the primary induction coil can be moved closer to the secondary coil device, as a result of which electrical energy transmission can be improved. The carrier device can be designed as a carrier plate or a housing into which the primary induction coil can be inserted. The carrier device can be arranged, for example, on a surface, in particular on a road surface, or can be incorporated into a surface, so that it is flush with the surface in the first state. The movement device can be designed as a lifting and lowering device, for example a hydraulic or electric lifting platform. Provision is preferably made for the movement device to be able to carry out a horizontal movement in addition to a vertical movement, for example by means of displacement on a rail. The movement device can particularly preferably automatically detect a position of the secondary coil device and automatically adjust a positioning of the primary induction coil by means of the movement device. An optical sensor such as a camera or a laser can be used for this purpose, for example. This aspect of the invention results in the advantage that the traction battery can be easily charged by accessing it from underneath the motor vehicle.

An embodiment of the system provides that in the second state the fuel tank is engaged by the primary induction coil. In other words, the fuel tank can be partially enclosed laterally by the primary induction coil. This means that in the second state or charging state, the primary induction coil and the secondary coil device can be arranged at a small distance, so that an efficient charging process can be carried out. Furthermore, a simple alignment to one another is possible, for example, in the case of a curved design from the secondary coil to the primary coil.

The invention also provides a method for charging a traction battery with a system according to one of the preceding embodiments, with step a) moving a motor vehicle into a charging position via the ground-side primary coil device, step b) moving a primary induction coil of the primary induction coil device from the first state to the second state, and as step c) charging the traction battery by inductive energy transfer from the primary coil device to the secondary coil device. This results in the same advantages and possible variations as in the case of the motor vehicle and the system.

The invention also includes the control device for the motor vehicle. The control device can have a data processing device or a processor device that is set up to carry out an embodiment of the method according to the invention. For this purpose, the processor device can have at least one microprocessor and/or at least one microcontroller and/or at least one FPGA (Field Programmable Gate Array) and/or at least one DSP (Digital Signal Processor). Furthermore, the processor device can have program code which is set up to carry out the embodiment of the method according to the invention when executed by the processor device. The program code can be stored in a data memory of the processor device.

The invention also includes developments of the method according to the invention, which have features as have already been described in connection with the developments of the motor vehicle according to the invention. For this reason, the corresponding developments of the method according to the invention are not described again here.

The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle.

The invention also includes the combinations of features of the described embodiments.

• 1 zeigt eine schematische Seitenansicht eines Systems mit einem Kraftfahrzeug gemäß einer beispielhaften Ausführungsform;
• 2 zeigt eine schematische Frontalansicht eines Systems mit einem Kraftfahrzeug gemäß einer beispielhaften Ausführungsform; und
• 3 zeigt ein schematisches Verfahrensdiagramm zum Laden einer Traktionsbatterie gemäß einer beispielhaften Ausführungsform.

Exemplary embodiments of the invention are described below. For this shows:

• 1 shows a schematic side view of a system with a motor vehicle according to an exemplary embodiment;
• 2 shows a schematic front view of a system with a motor vehicle according to an exemplary embodiment; and
• 3 12 shows a schematic process diagram for charging a traction battery according to an exemplary embodiment.

The exemplary embodiments explained below are preferred embodiments of the invention. At the execution examples, the described components of the embodiments each represent individual features of the invention which are to be considered independently of one another and which each also develop the invention independently of one another. Therefore, the disclosure is also intended to encompass combinations of the features of the embodiments other than those illustrated. Furthermore, the described embodiments can also be supplemented by further features of the invention that have already been described.

In the figures, the same reference symbols designate elements with the same function.

In 1 Illustrated is a schematic side view of a system 10 having an automotive vehicle 12 and a ground primary coil assembly 14 . The motor vehicle 12 can be designed as a fuel cell vehicle and have a fuel tank 16 for a fuel cell 18 and a traction battery 20 . In other words, the motor vehicle 12 can be designed as an electrically driven fuel cell vehicle which, in addition to the fuel cell 18, has a traction battery 20, which can also be referred to as a high-voltage battery. In this case, hydrogen or methanol can preferably be provided as fuel for the fuel tank.

The traction battery 20 can be designed to be charged by the fuel cell 18 on the one hand, but on the other hand the traction battery 20 can also be charged via a charging connection 22, to which a charging plug can be connected, and/or by means of a secondary coil device 24. The secondary coil device 24 is preferably arranged in a wall of the fuel tank 16 or on an outside of the fuel tank 16 toward an underside of the motor vehicle 12 . The secondary coil device 24 is particularly preferably adapted to a shape of the fuel tank 16, it being possible for the fuel tank 16 to be of cylindrical design. Consequently, the secondary coil device 24 can be curved at least partially around a lateral surface of the cylindrical shape of the fuel tank 16 so that it is positively connected to the fuel tank 16 .

The primary coil device 14 can have at least one primary induction coil 26 and a movement device 28 , the movement device 28 connecting the primary induction coil 26 to a carrier device 30 . A carrier plate, for example, which can be integrated into a road surface, can be provided as the carrier device 30 . The movement device 28 can be a lifting platform that can be raised with an electric motor. The movement device 28 can be designed to move the primary induction coil 26 towards the carrier device 30, preferably into a surface of the road, for a first state and to move the primary induction coil 26 away from the carrier device 30 to the secondary coil device 24 for a second state.

The primary induction coil 26 is preferably adapted to a shape of the fuel tank 16 and thus to a shape of the secondary coil device 24. The primary induction coil 26 can thus represent the matching counterpart to the secondary coil device 24, so that the primary induction coil and the secondary coil device 24 can be adapted to one another in the second state. In particular, in the second state of the movement device 28, the primary induction coil 26 can engage a shape of the fuel tank 16 and thus establish a minimum distance for an inductive charging process. The traction battery 20 can then be charged inductively via the secondary coil device 24 .

In 2 A schematic longitudinal view of the system 10 with the motor vehicle 12 of the primary coil device 14 is shown. In particular, a sectional view of the cylindrical fuel tank 16 having a substantially circular periphery is shown. As shown in the figure, the secondary coil assembly 24 may be at least partially curved around a lower half of the periphery of the fuel tank 16, with the secondary coil assembly 24 including one or more secondary induction coils 32 concentrically disposed around the periphery of the fuel tank 16. That is, an area vector of the respective secondary inductors 32 is oriented perpendicular to an outside of the fuel tank 16 . This has the advantage that the primary induction coil 26, which can be curved to complement the secondary coil device 24 and in particular can generate a correspondingly inwardly directed magnetic field, can produce improved energy transmission by means of electromagnetic induction to the respective secondary induction coil 32 when it engages in the fuel tank 16.

In 2 For example, the arrows from the primary induction coil 26 toward the secondary coil assembly 24 represent preferred movement by the movement assembly 28, more preferably the movement assembly 28 is also capable of horizontal movement to engage the fuel tank 16. For a suitable alignment of the primary induction coil 26 to the secondary coil device 24 it can be provided, for example, to use a positioning system with optical sensors (not shown).

In 3 Illustrated is a schematic method of charging a traction battery 20 for a system 10 according to an exemplary embodiment. In a step S10, the motor vehicle 12 is moved to a loading position via the ground-side primary coil device 14. Subsequently, in a step S12, the primary induction coil 26 can be moved by the movement device 28 from the first state, in which the primary induction coil 26 can be located on a carrier device 30, into a second state, in which the primary induction coil 26 is in engagement with the fuel tank 16 . Subsequently, in a step S14, the traction battery 20 can be charged by inductive energy transmission from the primary coil device 14 to the secondary coil device 24.

A further aspect of an exemplary embodiment provides that one or more secondary induction coils 32 are arranged on an outside of a hydrogen tank 16 . The secondary induction coils 32 are attached to the fuel tank 16 concentrically in such a way that the fuel tank 16 and the secondary induction coils 32 form a unit and the arrangement thus takes up little more space than a comparable conventional fuel tank. The primary inductor 26 is curved to exactly match the arrangement of the secondary inductors 32 . If the traction battery 20 of the motor vehicle 12 is to be charged inductively, the primary induction coil 26 is raised by a movement device 28 . The primary and secondary induction coils thread into one another through the formation. As soon as the distance between the coils is small enough, energy can be induced, as in conventional inductive charging, with which the traction battery 20 is charged.

This has the advantage that separate installation space is no longer required for the secondary induction coils 32 and space in the motor vehicle 12 can be saved and weight can be reduced since no additional components and fastening means have to be provided for the secondary induction coils 32 . A further advantage is that due to the arched design of the secondary induction coil 32 relative to the primary induction coil 26, simple alignment with one another is possible. After a position of the primary induction coil 26 relative to the secondary induction coil 32 has been approximately established, the primary induction coil 26 can be raised, whereby this can thread into the fuel tank 16 and thus into the secondary induction coils 32 due to the design. In addition, a large area of the fuel tank 16 is well suited to dissipate heat that can arise during inductive charging. This can be derived via the fuel tank 16 to a vehicle chassis.

In particular, one or more secondary induction coils 32 can be arranged concentrically, for example, on an underside of a hydrogen tank (fuel tank 16). Analogously to conventional induction coils, these secondary induction coils 32 are connected to a high-voltage system of the electric traction drive, for example to an on-board charger (OBC). The primary induction coil 26 can be a suitable counterpart to the secondary induction coils 32 and can be arranged on a support device 30 on the ground via a lifting and lowering device (moving device 28) so that the primary and secondary induction coils can be perfectly adapted to one another. If the motor vehicle 12 is not being charged, the primary induction coil 26 can be retracted and stowed on the floor or on the carrier device 30 . If the high-voltage battery or traction battery 20 is to be charged and the motor vehicle 12 or the hydrogen tank 16 is located above the primary coil device 14 , the latter is raised in the direction of the secondary induction coils 32 with the movement device. As soon as a distance between the primary and secondary induction coils is small enough, energy can begin to be induced with which the traction battery 20 can be charged. After the loading process is complete, the moving device can be retracted again.

Overall, the examples show how a combined hydrogen tank with an integrated inductive charging unit can be provided.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited 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 102015201788 A1 [0005]
• DE 102017205436 A1 [0006]
• FR 3030387 A1 [0007]

Claims (10)

Motor vehicle (12) with a fuel tank (16) for a fuel cell (18) and with a traction battery (20), characterized in that the fuel tank (16) has a secondary coil device (24) which is designed to generate a current by electromagnetic induction to generate and to charge the traction battery (20) with the electricity. Motor vehicle (12) after claim 1 wherein the secondary coil device (24) is arranged in a wall of the fuel tank (16) or on an outside of the fuel tank (16). Motor vehicle (12) after claim 2 , wherein the secondary coil device (24) is oriented substantially in the direction of an underside of the motor vehicle (12). Motor vehicle (12) according to one of claims 2 or 3 wherein the secondary coil device (24) is adapted to a shape of the fuel tank (16). A motor vehicle (12) according to any one of the preceding claims, wherein the fuel tank (16) is cylindrical with a substantially circular periphery and wherein the secondary coil assembly (24) is arcuate about the circular periphery. Motor vehicle (12) after claim 5 wherein the secondary coil assembly (24) is disposed about the circular periphery of the fuel tank (16) at a center angle of between 45 degrees and 180 degrees. Motor vehicle (12) according to one of claims 2 until 6 , wherein the secondary coil device (24) has a plurality of secondary induction coils (32), the secondary induction coils (32) being arranged such that a respective area vector of the respective secondary induction coils (32) is aligned perpendicular to the outside of the fuel tank (16). System (10) with a ground-side primary coil device (14) and a motor vehicle (12) according to one of the preceding claims, wherein the primary coil device (14) has at least one primary induction coil (26) and a movement device (28) which is attached to a carrier device (30) is arranged, wherein the primary induction coil (26) has a shape adapted to the fuel tank (16), wherein the movement device (28) is designed to move the primary induction coil (26) between a first and a second state, wherein in the first state the primary induction coil (26) is retracted onto or into the carrier device (30) and in the second state the primary induction coil (26) is extended for inductive energy transmission to the secondary coil device (24). system after claim 8 wherein in the second condition the fuel tank (16) is engaged by the primary induction coil (26). Method for charging a traction battery (20) with a system claim 8 or 9 , comprising the steps of: a) moving (S10) a motor vehicle (12) into a loading position over the ground-side primary coil device (14); b) Moving (S12) a primary induction coil (26) of the primary coil device (14) from a first state, in which the primary induction coil (26) is retracted onto or into a carrier device (30) of the primary coil device (14), into a second state, in wherein the primary induction coil (26) is extended for inductive energy transfer to a secondary coil assembly (24); and c) charging the traction battery (20) by inductive energy transfer from the primary coil device (14) to the secondary coil device (24).

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