Method for operating an electric motor vehicle

Abstract

A method for operating an electric motor vehicle comprising a traction battery (2), (1) is characterized in that an additional energy storage device (3) of the motor vehicle (1) is charged in a primary charging process and the energy storage device (3) is subsequently used in a secondary charging process for charging the traction battery (2) and / or for operating an electrical consumer of the motor vehicle (1), wherein energy from the energy storage device (3) is converted into electrical energy.

Description

[0001] The invention relates to a method for operating an electric motor vehicle.

[0002] According to the invention, an "electric motor vehicle" is defined as a motor vehicle comprising at least one electric traction motor capable of propelling the vehicle on its own. The motor vehicle may consist solely of the at least one electric traction motor ("electric vehicle") or the at least one electric traction motor may be provided in addition to another drive device, in particular an internal combustion engine ("hybrid vehicle"). The at least one electric traction motor is typically powered by a (traction) battery. For charging such a traction battery, an electric motor vehicle generally includes a charging port with a connector to which a mating connector of an external charging station can be connected.

[0003] Charging the traction battery of an electric vehicle still requires a considerable amount of time, even when done at a fast-charging station that provides maximum charging capacities of 100 kW or more. Such fast-charging stations are typically used when a vehicle's journey is interrupted solely or primarily due to the need to charge the battery. This interruption can be perceived as disruptive by vehicle users because it can significantly increase the travel time required to cover a defined distance.

[0004] EP 2 994 343 B1 describes the possibility of charging the battery of an electric motor vehicle wirelessly when stationary, for example inductively, i.e. with energy transfer through a changing magnetic field.

[0005] EP 4 201 761 A1 discloses a wireless charging of a battery of an electric motor vehicle while driving.

[0006] Charging the battery of an electric motor vehicle while driving is also described in EP 3 578 411 B1, whereby a mobile charging station is temporarily coupled to the motor vehicle.

[0007] The invention is based on the objective of demonstrating a way to achieve the greatest possible range for a journey of an electric motor vehicle and / or the shortest possible charging stops for charging a traction battery of the motor vehicle.

[0008] This problem is solved by carrying out a method according to claim 1. A motor vehicle suitable for carrying out such a method is the subject of claim 10, and a charging station usable in carrying out a method according to the invention is the subject of claim 14.

[0009] A method according to the invention for operating an electric motor vehicle comprising a traction battery (2) is characterized in that an additional (i.e., not corresponding to the traction battery) energy storage device of the motor vehicle is charged in a primary charging process and the energy storage device is subsequently used in a secondary charging process for charging the traction battery and / or directly (i.e., bypassing the traction battery) for operating at least one electrical consumer, in particular a traction motor, of the motor vehicle, wherein a direct or indirect conversion of energy from the energy storage device into electrical energy takes place. The energy storage device thus stores energy in a different form compared to electrical energy.

[0010] The additional energy storage system in the vehicle increases the total energy stored in the vehicle, which is available directly and indirectly for propulsion. This allows for the greatest possible driving range, guaranteed by the traction battery, and / or relatively short charging stops for the traction battery to achieve a defined driving range. Storing energy in the additional storage system in a form other than electrical energy enables advantageous, and especially rapid, charging of the additional energy storage system.

[0011] An electric motor vehicle suitable for carrying out a method according to the invention comprises at least one traction battery, an additional energy storage device, and an energy converter configured to convert energy provided by the energy storage device into electrical energy and to supply this electrical energy to the traction battery and / or directly to at least one electrical consumer of the motor vehicle. As an electric motor vehicle, this further comprises at least one electric traction motor configured to propel the motor vehicle.

[0012] The additional energy storage device is part of the vehicle and is therefore intended for permanent integration. This integration can be permanently fixed, meaning the energy storage device is not designed for regular replacement, but only for replacement during repairs or maintenance. Alternatively, the integration can be designed to be replaceable, allowing for regular replacement and ensuring the integration is structurally designed to be quick and non-destructively removable.

[0013] A motor vehicle according to the invention can in particular be a wheel-based and non-rail-bound motor vehicle (preferably a passenger car or a truck or a motorized two- or three-wheeler).

[0014] The invention also relates to an (external) charging station for charging a motor vehicle according to the invention or for use in the context of a method according to the invention, wherein the charging station comprises a charging device which is equipped for charging the additional energy storage of the motor vehicle.

[0015] According to a preferred embodiment of a method according to the invention, the secondary charging process can be carried out while the vehicle is in operation, so that the provision of electrical energy by the additional energy storage device takes place during such operation. This can increase the vehicle's driving range and / or allow for a relatively short charging stop for the traction battery, taking into account the achievement of a defined driving range.

[0016] "Driving operation" refers to the operation of a motor vehicle in which driving or moving the vehicle with the aim of covering a distance is intended and therefore fundamentally possible. Such driving operation can also include periods of standstill, for example, at a red traffic light. Driving operation can be initiated, for example, by activating a corresponding driving mode switch, thereby placing the vehicle into a driving mode state via a control device.

[0017] It can be structurally quite complex to simultaneously discharge (due to the energy consumption, particularly of the traction motor) and charge (through a secondary charging process) the traction battery while driving. This would require selectively charging individual battery cells and discharging others. Against this background, it can be advantageous to use the electrical energy provided by the energy storage system directly to operate an electrical consumer, at least during driving.

[0018] According to a preferred embodiment of a method according to the invention, the primary charging process can be carried out during a charging stop of the motor vehicle containing the energy storage device. This can be particularly advantageous if the additional energy storage device is permanently integrated into the motor vehicle. This can result in an advantageous, and in particular relatively simple and cost-effective, design for the motor vehicle. A "charging stop" is understood to mean an interruption of the motor vehicle's driving operation for the purpose of charging the traction battery and / or the additional energy storage device.

[0019] According to an alternative embodiment of a method according to the invention, the primary charging process can be carried out on the energy storage device, which is separate from the vehicle, before a charging stop, and the energy storage device is integrated into the vehicle during the charging stop. This allows for the shortest possible charging stop, because during the charging stop only the already charged energy storage device needs to be integrated into the vehicle, which can preferably be achieved quickly and easily by inserting the energy storage device into a designated receptacle in the vehicle. An electrical connection between the energy storage device and the vehicle's electrical infrastructure can, in particular, be established automatically during the insertion of the energy storage device.

[0020] Preferably, the traction battery of the motor vehicle can be charged directly in a main charging process, i.e., not via the additional energy storage device, by means of a charging station according to the invention. For this purpose, a motor vehicle according to the invention can include a vehicle charging port connected to the traction battery, which is configured to be connected to a station charging port of the external charging station. A charging station according to the invention can therefore include such a station charging port, which is configured for a connection to the vehicle charging port, in particular a wired connection.

[0021] The main charging process can preferably be carried out during a charging stop. This allows for the shortest possible charging stop for the vehicle, because it is possible to charge the traction battery only to a relatively small extent during the main charging process. This is because additional charging, particularly during subsequent driving after the charging stop, can be carried out by the energy storage device during the secondary charging process, and / or the power required by the traction battery is reduced because additional electrical power is provided by the additional energy storage device.Accordingly, according to a preferred embodiment of a method according to the invention, it can be provided that a total charging requirement of the traction battery, in particular a total charging requirement of the traction battery for a specific charging stop, is determined and a first part of the total charging requirement is covered by the main charging process and a second part of the total charging requirement, in particular the remainder of the total charging requirement, is covered by the secondary charging process and / or compensated by operation of the at least one electrical consumer by the additional energy storage device.

[0022] According to a preferred embodiment of a method according to the invention, the additional energy storage device can be charged using electromagnetic radiation, in particular laser radiation. This allows for the fastest possible and contactless primary charging process. The additional energy storage device of a motor vehicle according to the invention can therefore be designed to be charged using electromagnetic radiation. The electromagnetic radiation used to charge the additional energy storage device can, in principle, be of any type. However, in the case of certain types of electromagnetic radiation, such as X-rays, additional protective mechanisms should be provided to shield the radiation in order to prevent it from having harmful effects, particularly on people. The electromagnetic radiation preferably has a wavelength in the range of 10 -8 m to 10 -4exhibit m. Furthermore, it may advantageously, but need not, be monochromatic.

[0023] It is particularly advantageous to provide that the electromagnetic radiation used to charge the additional energy storage device during the primary charging process is high-frequency. This allows for the fastest possible charging of the energy storage device. Electromagnetic radiation is considered "high-frequency" if it has a frequency of 7.5 × 10⁻⁶ or higher. 14 1 / s.

[0024] It is further preferred that the secondary charging process and / or the operation of the at least one electrical consumer includes a direct or indirect conversion of electromagnetic radiation and / or heat energy emitted by the additional energy storage device into electrical energy. Accordingly, the energy converter of a motor vehicle according to the invention can be configured to convert electromagnetic radiation and / or heat energy into electrical energy. Such an energy converter can be designed with a relatively simple construction and thus be implemented cost-effectively.

[0025] Preferably, the electromagnetic radiation used to convert electrical energy during secondary charging and / or for operating the at least one electrical load is low-frequency. The associated relatively low-power energy transfer allows for a relatively simple design of the energy converter. This is unproblematic for operating the at least one electrical load, as additional electrical power can be supplied by the traction battery if higher power is required. Regarding secondary charging, the relatively slow charging of the traction battery resulting from such a relatively low-power energy transfer can, in principle, be advantageous for the battery's service life.At the same time, a relatively large amount of time may be available for the secondary charging process, especially if it is carried out while the vehicle is being driven, so that a relatively slow charging process does not necessarily have to be a disadvantage.

[0026] Preferably, the electromagnetic radiation emitted by the additional energy storage device may comprise photons, so that the operation of the additional energy storage device can be based on luminescence. Accordingly, at least one material of the energy storage device can be brought into an excited state by externally supplied energy, in particular electromagnetic radiation, most preferably by laser radiation, wherein the excited material emits photons during a subsequent transition to the ground state.

[0027] The operation of the energy converter of a motor vehicle according to the invention can preferably be based on photovoltaics, which enables the use of readily available, cost-effective energy converters (“solar cells” or photodiodes).

[0028] Excitation of a material of the additional energy storage device can preferably be vibrational excitation or, more preferably, based on an electronic (electron) transition.

[0029] If the primary charging process includes charging the additional energy storage device by electromagnetic radiation and using the energy of the additional energy storage device involves converting heat energy into electrical energy, the operation of the energy storage device can preferably be based on a photoinduced, endothermic, chemical reaction of a substance of the energy storage device to the electromagnetic radiation in order to increase the chemical energy and thus charge the energy storage device.

[0030] When converting thermal energy into electrical energy, the energy converter can preferably be designed as a conventional, readily available thermoelectric generator. However, an intermediate conversion into mechanical energy can also be advantageous in this case, for example, using a piston engine or a turbine, utilizing the expansion of a gas. To convert the mechanical energy into electrical energy, such a piston engine or turbine can then be coupled to an electric machine acting as a generator.

[0031] The invention also relates to a combination of a motor vehicle according to the invention and a charging station according to the invention.

[0032] The invention is explained in more detail below with reference to exemplary embodiments illustrated in the drawings. The drawings show, in simplified representations: Fig. 1: a functional principle for carrying out a method according to the invention, Fig. 2: an exemplary state of charge of a traction battery and an additional energy storage device of a motor vehicle according to the invention at the beginning of a station charging process, Fig. 3: an exemplary state of charge of the traction battery and the vehicle's additional energy storage at the end of the station charging process and Fig. 4: an exemplary state of charge of the traction battery and the additional energy storage of the vehicle after the station charging process.

[0033] The Fig. Figure 1 shows a schematic diagram for carrying out a method according to the invention for operating an electric motor vehicle 1.

[0034] The motor vehicle 1 comprises, in addition to the traction battery 2, an additional energy storage device 3, an energy converter 4, and a traction motor 5. The traction motor 5 is designed to provide propulsion power for driving the motor vehicle 1, with the required electrical power being supplied by the traction battery 2.

[0035] The additional energy storage medium 3 comprises a substance that can be excited by high-frequency electromagnetic radiation 8. This substance can, for example, be Cr. 3+ -based compounds or aluminate crystals (e.g. SrAl2O4:Eu 2+The material can also be liquid. The electromagnetic radiation can be generated and emitted by a (first) charging device 7 of a charging station 6 to charge the additional energy storage device 3 relatively quickly in a primary charging process. The first charging device 7 can, in particular, include a laser for generating and emitting corresponding laser radiation. The laser can, for example, be a solid-state laser that emits high-frequency UV laser radiation. This can be neodymium-based.

[0036] The excitable material of the additional energy storage 3 is in turn designed such that, in the excited state, it itself emits low-frequency electromagnetic radiation 9 (e.g., in the UV or visible spectrum; e.g., with a wavelength of 520 nm for SrAl2O4:Eu). 2+) emitted, which is converted into electrical energy by the energy converter 4. The energy converter 4 can, for example, comprise a photovoltaic cell in the form of a polycrystalline silicon cell. This electrical energy can be used to charge the traction battery 2, which is electrically connected to the energy converter 4. It may also be possible to use the electrical energy supplied by the additional energy storage device 3 via the energy converter 4 directly to operate at least one electrical consumer of the motor vehicle 1, in particular the traction motor 5.

[0037] A reduction in the energy potential of the energy storage device 3 caused by the emission of low-frequency electromagnetic radiation 9 occurs significantly more slowly than the increase in energy potential caused by excitation by high-frequency electromagnetic radiation 8. "Energy potential" here refers to the amount of energy stored in the additional energy storage device 3 that can be made available for charging the traction battery 2 in the secondary charging process and / or for directly operating an electrical load by transferring it to the energy converter 4. Accordingly, the energy storage device 3 can be charged relatively quickly using the first charging device 7 of the charging station 6, while the electrical power provided by the additional energy storage device 3 and via the energy converter 4 is relatively low. A secondary charging process would therefore proceed only relatively slowly.

[0038] The charging station 6 further comprises a second charging device 10, which is configured to directly charge the traction battery 2 in a main charging process. This second charging device 10 can correspond to a charging device of a conventional charging station configured for charging a traction battery of a motor vehicle and therefore provides alternating or direct current, in particular with a maximum power of at least 100 kW, at a station charging port 11, wherein the station charging port 11 can be connected in a known manner to a vehicle charging port 13 of the motor vehicle 1 via a charging cable 12. The vehicle charging port 13 is in turn electrically connected to the traction battery 2 (via a charger of the motor vehicle 1, not shown, for controlling the main charging process).

[0039] The Fig. 2, Fig. 3 to Fig. Figure 4 shows various exemplary charge states of the traction battery 2 and the additional energy storage device 3 of a motor vehicle 1 according to the invention, for example, as shown in the Fig. 1.

[0040] In the Fig. Figure 2 shows an example of the state of charge at the beginning of a charging station process, which includes both a main charging process and a primary charging process. This state of charge can occur, for example, when the vehicle 1 is connected to the charging station 6 for charging the traction battery 2 during a charging stop.

[0041] As an example, the traction battery 2 is shown to have a state of charge (SOC) of 20% in this charging state. This state of charge will be increased to, for example, 70% by the main charging process by the end of the station charging process, according to the Fig. 3. Simultaneously, the additional energy storage device 3, which had an energy potential of zero at the beginning of the station charging process, is fully or as far as possible charged by means of the first charging device 7 of the charging station 6, whereby the realized energy potential of the energy storage device 3 then corresponds approximately to the remaining 30% of a 100% state of charge of the traction battery 2. At the end of the station charging process, therefore, enough energy, directly or indirectly available for driving the traction motor 5, can be stored in the traction battery 2 and the additional energy storage device 3 to correspond to a state of charge of 100% for the traction battery 2.The energy stored in the additional energy storage unit 3 can be used for this purpose after the station charging process, for example also during a subsequent journey of the vehicle 1 following the charging stop, for a recharging or further charging of the traction battery 2, as is the case in the . Fig. Figure 4 shows that, additionally or alternatively, the energy stored in the additional energy storage unit 3 can also be used for the direct operation of at least one electrical consumer, thereby reducing the power supply by the traction battery accordingly.

[0042] The method according to the invention enables the charging of the vehicle's energy storage devices (traction battery 2 and additional energy storage device 3) during a relatively fast or short charging process at a charging station. This transfer of energy corresponds to a 100% charge level for the traction battery 2, thus providing a correspondingly long driving range for the vehicle 1. The relatively short duration of the charging process is due to the fact that the traction battery 2 is not fully charged during the main charging process, while the additional energy storage device 3 is simultaneously charged quickly during the primary charging process. This energy from the additional energy storage device 3 is then used after the charging process to further charge the traction battery 2 and / or directly to operate at least one electrical consumer. Reference symbol list 1 motor vehicle 2 traction batteries 3 additional energy storage units 4 energy converters 5 traction motor 6 charging stations 7 first charging device 8 high-frequency electromagnetic radiation 9. Low-frequency electromagnetic radiation 10 second charging device 11 station charging ports 12 charging cables 13 Vehicle charging port QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2 994 343 B1

[0004] EP 4 201 761 A1

[0005] EP 3 578 411 B1

[0006]

Claims

[1] Method for operating an electric motor vehicle (1) comprising a traction battery (2), characterized by , that an additional energy storage device (3) of the motor vehicle (1) is charged in a primary charging process and the energy storage device (3) is subsequently used in a secondary charging process for charging the traction battery (2) and / or directly for operating at least one electrical consumer of the motor vehicle (1), whereby energy from the energy storage device (3) is converted into electrical energy. [2] Method according to claim 1, characterized by , that the secondary charging process is carried out while the motor vehicle (1) is in operation. [3] Method according to any one of the preceding claims, characterized by , that the primary charging process is carried out during a charging stop of the motor vehicle (1) comprising the energy storage device (3). [4] Method according to one of claims 1 or 2, characterized by, that the primary charging process is carried out on the energy storage device (3) separated from the motor vehicle (1) before a charging stop and the energy storage device (3) is integrated into the motor vehicle (1) during the charging stop. [5] Method according to any one of the preceding claims, characterized by , that the traction battery (2) is charged directly by means of an external charging station (6) during a main charging process. [6] Method according to claim 3 or 4 and claim 5, characterized by that the main charging process is carried out during the charging stop. [7] Method according to claim 5 or 6, characterized by, that a total charging requirement of the traction battery is determined and a first part of the total charging requirement is covered by the main charging process and a second part of the total charging requirement is covered by the secondary charging process and / or compensated by the operation of at least one electrical consumer by the additional energy storage. [8] Method according to any one of the preceding claims, characterized by , that the charging of the energy storage device (3) is carried out by means of electromagnetic radiation. [9] Method according to any one of the preceding claims, characterized by , that the secondary charging process and / or the operation of the at least one electrical consumer involves the conversion of electromagnetic radiation and / or heat energy into electrical energy. [10] Motor vehicle (1) with a traction battery (2), characterized byan additional energy storage device (3) and an energy converter (4) which is configured to convert energy supplied by the energy storage device (3) into electrical energy and to supply this electrical energy to the traction battery (2) and / or directly to an electrical consumer of the motor vehicle. [11] Motor vehicle (1) according to claim 10, characterized by , that the energy storage device (3) can be charged by means of electromagnetic radiation. [12] Motor vehicle according to claim 10 or 11, characterized by , that the energy converter (4) is designed to convert electromagnetic radiation and / or heat energy into electrical energy. [13] Motor vehicle according to any one of claims 10 to 12, characterized by a vehicle charging port (13) connected to the traction battery (2), which is designed to be connected to a station charging port (11) of an external charging station (6). [14] Charging station (6) for charging a motor vehicle (1) according to one of claims 10 to 13, characterized by a charging device (7) which is designed for charging the additional energy storage device (3) of the motor vehicle (1). [15] Charging station (6) according to claim 14 for charging a motor vehicle (1) according to claim 13, characterized by a station charging port (6) which is designed for connection to the vehicle charging port (13).

Images