Charging device and method for charging an electrical energy store of an electrically operated vehicle

Abstract

The invention relates to a charging device (100) for charging an electrical energy store (60) of an electrically operable vehicle (200), having a charging connection (50) for electrically connecting the charging device (100) to an external voltage supply, a charging unit (10) for converting a first DC voltage applied at the charging connection (50) into a second DC voltage, which is provided for charging the electrical energy store (60), and a power distributor unit having first and second outputs (36, 38) for supplying the first DC voltage applied at the charging connection (50) and / or the second DC voltage converted by the charging unit (10) to the electrical energy store (60), to which the electrical energy store is attached at the outputs (36, 38). The power distributor unit (30) has a first electrical connection (52) for the charging connection (50) and a second electrical connection (56) for the charging unit (10). Furthermore, the invention relates to a method for charging an electrical energy store (60) of an electrically operable vehicle (200) by means of such a device (100).

Description

Technical Field

[0001] The present invention relates to a charging device for charging an electric energy storage device of an electrically powered vehicle, and a method for charging an electric energy storage device of an electrically powered vehicle by means of such a device. Background Technology

[0002] If the existing high-voltage onboard network architecture of a vehicle capable of electric operation is based on an 800V onboard network voltage, then an additional 400V / 800V DC-DC converter is required at a 400V charging station in order to charge the vehicle's electric energy storage device.

[0003] DE 102019003459 A1 discloses a charging device for charging a high-voltage battery. The charging device has a DC voltage connector for connecting the charging device to an external charging connector. The charging device also includes an AC voltage connector for connecting the charging device to a second external charging connector and a DC voltage converter for converting a first DC voltage from a first charging connector to a second DC voltage, which is supplied to the high-voltage battery. Similarly, the charging device includes an on-board charger for converting the AC voltage from the second charging connector to the second DC voltage. The parallel connection of the DC voltage converter and the on-board charger allows the first DC voltage to be converted to a second DC voltage that is higher than the first DC voltage. The charging device is a charging unit for an electrically operated vehicle, enabling the charging of the vehicle's high-voltage battery. The parallel connection of the DC voltage converter and the on-board charger allows the conversion of a DC voltage from the first external charging connector, which is lower than the battery voltage of the high-voltage battery, to a second DC voltage.

[0004] Such DC-DC voltage converters (also known as DC / DC converters) have been known for a long time and in various forms in power electronics, both in terms of the interconnection of the components themselves, and are described, for example, in the literature in Chapter 18, “DC-DC Voltage Converters,” of Joachim Specovius’s book, *Grundkurs Leistungselektronik*, 3rd edition, 2009. Here, DC-DC voltage converters can also be classified as buck choppers, boost choppers, and buck-boost choppers. The boost chopper shown there is implemented, for example, as a so-called half-bridge converter, in which, at the first terminal, the voltage is typically applied from the input to the output in a substantially unchanged manner, and at the second terminal, through components and corresponding circuitry, the voltage is converted from the input terminal with a lower voltage to the output terminal with a higher voltage.

[0005] The so-called charge pump can also be used as a boost chopper. The charge pump is also called a charge multiplier because of its fixed conversion ratio of 1:2, and is also known to those skilled in the art as a general prior art.

[0006] In DC-DC voltage converters, for all types, there is the possibility that, especially in the case of electrically coupled DC-DC voltage converters, one implementation of the DC-DC voltage converter is chosen in which the voltage position at one pole is directly coupled between the input and output terminals and is therefore immutable, so that the voltage position at the other pole is subsequently changed between the input and output terminals and is thus converted. Summary of the Invention

[0007] The objective of this invention is to provide an improved charging device for charging an electric energy storage device in an electrically powered vehicle.

[0008] Another task is to provide a method for charging the electric storage devices of electrically powered vehicles using such improved charging equipment.

[0009] According to one aspect of the invention, a charging device is provided for charging an electric energy storage device of an electrically operable vehicle. The charging device includes a charging connector, a charging unit, and a power divider unit. The charging connector is used to electrically connect the charging device to an external voltage supply device. The charging unit is used to convert a first DC voltage applied to the charging connector into a second DC voltage, which is configured to charge the electric energy storage device. The power divider unit has first and second output terminals, which are used to provide the first DC voltage applied to the charging connector and / or the second DC voltage converted by the charging unit to the electric energy storage device, which is attached to the output terminals. Here, the power divider unit has a first electrical connector for the charging connector and a second electrical connector for the charging unit. The power divider unit has a switch, by means of which, in a first charging state, the charging connector is switched to the first and second output terminals, and in a second charging state, the first output terminal of the charging unit is switched to one of the output terminals of the power divider unit, and the second output terminal of the charging unit is switched to the other output terminal of the power divider unit.

[0010] According to the present invention, in this charging device, in a first charging state, a first DC voltage at the charging connector can be switched to the first and second output terminals of the power divider unit, and in a second charging state, a second DC voltage converted by the charging unit is switched to the first and second output terminals of the power divider unit. In the first charging state, the energy storage device can be charged directly via a DC voltage applied to the charging connector, which is attached to the output terminal of the power divider unit and has, for example, a rated voltage of 800V, and the DC voltage is also 800V. In the second charging state, when a first DC voltage of, for example, only 400V is provided at the charging connector, this first DC voltage can be converted to a second DC voltage of 800V by the DC voltage converter of the charging unit, and thus the energy storage device is also charged at 800V.

[0011] Similarly, according to the present invention, in a charging device, during a second charging state where the first DC voltage, particularly at the charging connector, is less than the rated voltage of the energy storage device, the first output terminal of the charging unit can be interconnected with the first pole of the charging connector and directly with the first output terminal of the power divider unit via a first switch of the power divider unit. Here, the second output terminal of the charging unit can be interconnected with the second output terminal of the power divider unit, and the input terminal of the charging unit can be interconnected with the second pole of the charging connector. Here, a switch is provided in the charging unit that connects the input terminal of the charging unit to the input terminal of the DC-DC converter of the charging unit.

[0012] Here, the first output terminal of the charging unit is connected to the output capacitor and the input capacitor, and the first output terminal of the charging unit is also used as the input terminal of the charging unit.

[0013] With this purposeful interconnection, the first DC voltage can be connected to the charging unit, converted into a second DC voltage, and then connected to the output of the power divider unit. Advantageously, only one triode harness is needed for connecting the power divider unit and the charging unit.

[0014] Advantageously, the charging unit of the charging device according to the invention is not arranged between the charging connector and the power divider unit as in the prior art, and thus has two input terminals and two output terminals, but can be accessed from the power divider unit, requiring only three connectors for this purpose. Correspondingly, a direct connection between the charging connector and the power divider unit is therefore possible. This corresponds to the function of the bypass circuit of the charging unit, which is subsequently no longer implemented through the charging unit. The power divider unit includes all other charging-related components, such as components for a so-called high-voltage intermediate circuit, which has, for example, components for connecting the energy storage device to the high-voltage vehicle network. The charging unit can have a standard-compliant DC-DC voltage converter configured as a boost converter, so that electric vehicles (EVs) with high-voltage vehicle networks with higher voltages, such as 800V, can also be charged at DC charging stations at lower voltages, such as 400V.

[0015] The interconnection of charging devices offers advantages primarily in terms of contacts and wiring harnesses, especially in the case of high-voltage lines. With the charging device according to the invention, the same functionality as in conventional charging devices can be achieved, and it is still possible to charge using simple direct current (DC), where the charging voltage corresponds to the system voltage of the vehicle network or energy storage device, via a direct connection between the charging connector and the power divider unit. Here, the charging unit is not loaded. The charging current is also not guided through the charging unit, which simplifies the wiring harness, requires fewer contact points, and is therefore better in terms of heat generation and cooling.

[0016] Advantageously, in the charging device according to the invention, the charging unit having a DC voltage converter as an electrically coupled converter is integrated into the existing high-voltage vehicle network architecture. Here, when charging an 800V energy storage device at a 400V charging station, the serial charging path of the charging device can be kept open by an existing switch, thereby applying a first DC voltage of 400V from the charging station to the input side of the charging device, and using the 800V from the DC voltage converter at the output of the power divider unit to charge the energy storage device. The values ​​of 800V and 400V here are, of course, example values ​​used to illustrate the advantages and benefits of the invention, and, as is known to those skilled in the art, are not fixed, permanently applied values, but depend on the charging state of the energy storage device or on the charging station, and are within a wide voltage band symbolized by these values.

[0017] Such charging devices typically eliminate the need for an additional DC contactor located between the charging connector and the DC / DC charging contactor, which serves as a bypass circuit for the DC-DC voltage converter.

[0018] It eliminates the need for changes to the high-voltage series wiring harness.

[0019] The charging device only requires one two-pole high-current connector (e.g., a two-pole 500A connector) to attach the charging head, while in order to attach the charging unit to the power divider unit, only two three-pole connectors (e.g., two three-pole 125A connectors) are needed for lower power.

[0020] Since a bypass path is not required through the charging unit when charging at an 800V charging station, bypass switches, such as high-voltage contactors, can be eliminated. This reduces structural space by omitting the high-current conductive rails. Furthermore, the charging unit does not experience the temperature rise that often occurs when a high-current bypass path forms a loop through the charging unit, which is typically necessary.

[0021] The charging unit only needs to be designed for lower charging power, allowing it to be constructed more compactly and lightly. The charging unit, along with the switches, connectors, and cables installed within or at the charging unit, only need to be designed for the charging unit's own nominal current.

[0022] This ensures that the charging unit is consistent with currently known charging standards.

[0023] It also simplifies the integration of the charging equipment into the vehicle, as the charging equipment has only one high-voltage connector at the power divider unit and a small bending radius for the high-voltage lines.

[0024] The savings in additional plug connectors and high-voltage contactors result in significant cost and weight savings.

[0025] Advantageously, the charging device according to the invention can be used to charge the electric storage device of electrically operated vehicles using common DC charging methods or DC charging standards, such as CCS type 1 or CCS type 2 (CCS = "Combined Charging System", as a standard developed in Europe), which allows charging with both DC and AC currents via a type 2 plug, CHAdeMO ("Chargede Move", as a standard developed in Japan, which typically has a charging power up to 50 kW), and GB / T (as a standard developed in China).

[0026] Advantageously, the charging equipment can also be used with future standards, such as ChaoJi (for CHAdeMO standard 3.0, which has a charging power up to 500kW) and MegaWatt charging. MegaWatt charging, by virtue of its charging voltage at a high on-board voltage level, does not require guidance through the charging unit. Similar to the advantages of charging at 800V charging stations, it also avoids the heating of the charging unit caused by a high-current bypass path forming a loop, which is typically necessary. Thus, the charging equipment not only possesses the current advantages of charging at 800V and 400V charging stations but can also be applied in a future-proof manner with future charging standards, offering the same advantages therein.

[0027] Through the arrangement and interconnection of charging units and DC voltage converters, new electric vehicles with high-voltage on-board voltages greater than 500V, such as 800V, can not only be charged at DC charging stations with the same high charging voltage, but also be charged in a backward compatible manner at charging stations with lower voltages, such as 400V, via the charging units of the charging equipment.

[0028] According to an advantageous configuration of the charging device, the DC voltage converter can be constructed as a boost converter. Advantageously, the first DC voltage of 400V can therefore be converted into a second DC voltage of 800V required to charge an energy storage device with a rated voltage of 800V.

[0029] According to an advantageous configuration of the charging device, in a first charging state, particularly at the charging connector, where the first DC voltage is greater than or equal to the rated voltage of the energy storage device, the first and second switches can be closed, and the third switch can be open. Here, the first DC voltage is applied between the first and second output terminals of the power divider unit. In this way, the DC voltage applied at the charging connector can be directly connected to the output terminal of the power divider unit and thus to the input terminal of the energy storage device.

[0030] According to an advantageous configuration of the charging device, the first electrical connector of the power divider unit can have a two-pole high-current plug connector. Advantageously, therefore, in order to attach the charging connector to the power divider unit, only a cable with such a plug connector is required.

[0031] According to an advantageous configuration of the charging device, the second electrical connector of the power divider unit can have a three-prong plug connector. The charging unit can therefore be advantageously attached to the power divider unit via a cable having two three-prong plug connectors.

[0032] Alternatively, a two-pole connector and a single-pole connector can be provided, thus replacing the one-piece connector with three poles, with two connectors arranged, one with two poles and the other with one pole. Here, the two connectors are then interconnected separately via two independent connection devices, in particular two cables, or they can also be connected via a common cable (also as a cable bundle) or a single cable to two attachment devices for the two connectors, one of which has one pole and the other has two poles.

[0033] In another alternative implementation, the connector can also be configured as three individual plug connectors, each with a unique pole; however, this is slightly more complex and also because a higher number of plug connectors is more prone to failure.

[0034] Advantageously, the second electrical connector of the power divider unit and the third electrical connector of the charging unit are implemented complementaryly, allowing the second electrical connector of the power divider unit to be directly connected to the third electrical connector of the charging unit without a connecting device. For example, in the power divider unit, the socket can be directly arranged in the housing, and in the charging unit, a matching mating part can be directly arranged in the housing as a plug, thereby enabling a direct connection between the power divider unit and the charging unit via a plug-socket connection in both housings.

[0035] Alternative connection devices can be used between plug-in connectors, whether in the case of a single plug-in connector with three poles or in the case of two plug-in connectors, one with one pole and the other with two poles. This can be achieved, for example, through conductive rails, i.e., fixed pre-formed wiring devices, or so-called direct connections. In the case of a direct connection, the connection device between the charging unit's plug-in connector and the power divider unit's plug-in connector is completely eliminated; the charging unit's plug-in connector and the power divider unit's plug-in connector are directly connected, i.e., inserted into each other. This not only eliminates connection devices, especially cables, saving weight and cost, but also improves conductivity and reduces sources of failure by using a smaller number of contacts.

[0036] According to an advantageous configuration of the charging device, a third electrical connector can be provided at the charging unit, which is attached to the second electrical connector of the power divider unit. In particular, the third electrical connector can have a three-prong plug connector. The charging unit can therefore be advantageously attached to the power divider unit via a cable having two three-prong plug connectors.

[0037] Advantageously, only one two-pole high-current plug connector is needed to attach the charging connector to the power divider unit, and only two three-pole plug connectors designed for lower nominal current are needed to attach the charging unit to the power divider unit.

[0038] According to an advantageous configuration of the charging device, in the second charging state, the positive terminal of the charging connector can be a common reference for the first DC voltage applied to the charging connector and the second DC voltage applied to the first and second output terminals of the power divider unit. With this advantageous interconnection, it is possible to switch the 400V first DC voltage to the input terminal of the charging unit and the 800V second DC voltage from the output terminal of the charging unit to the output terminal of the power divider unit. Advantageously, interconnection can be achieved via a three-pole cable. Alternatively, or reinterpreted, the same applies to the negative terminal.

[0039] According to another aspect of the present invention, a method is provided for charging an electric energy storage device of a vehicle capable of electric operation using the charging device described above. Here, the method includes at least the following steps: comparing a maximum voltage, which is a first DC voltage, that can be provided by the charging station with a maximum voltage, which is the rated voltage of the electric energy storage device and necessary for charging the energy storage device.

[0040] The maximum voltage that the charging station can provide as the first DC voltage is typically determined or exchanged during charging via communication between the vehicle and the charging station, or requested by the vehicle and transmitted from the charging station. Furthermore, this voltage can also be measured before closing the charging contactor to ensure that there is no excessive voltage difference between the charging voltage and the pre-charging voltage in the high-voltage intermediate circuit, so as not to damage the contactor upon closing.

[0041] In the following text, the first DC voltage always refers to the maximum possible voltage that the charging station can provide, and the rated voltage refers to the maximum required voltage of the energy storage device, which is necessary for charging.

[0042] If the first DC voltage is greater than or equal to the rated voltage of the energy storage device, the method further includes the following steps: closing the first and second switches of the power divider unit to connect the charging connector to the first and second output terminals of the power divider unit; switching the first DC voltage to the first and second output terminals via the first and second switches; and charging the energy storage device with the first DC voltage.

[0043] If the first DC voltage is less than the rated voltage of the energy storage device, the method further includes the following steps: closing a first switch to connect the first terminal of the charging connector to the first output terminal of the energy storage device and the first output terminal of the charging unit; opening a second switch of the power divider unit and connecting the input terminal of the charging unit to the second terminal of the charging connector; closing a third switch of the charging unit to connect the input terminal of the charging unit to the input terminal of the DC voltage converter of the charging unit; switching the second DC voltage converted by the charging unit to the first and second output terminals of the power divider unit; and charging the energy storage device with the second DC voltage.

[0044] Advantageously, according to the method of the invention, in a first charging state where the first DC voltage is greater than or equal to the rated voltage of the energy storage device, the first DC voltage applied to the charging connector can be directly connected to the output terminal of the power divider unit. Therefore, the energy storage device electrically connected to the output terminal can be charged with the first DC voltage.

[0045] Furthermore, in the second charging state where the first DC voltage is lower than the rated voltage of the energy storage device, the first DC voltage can be switched to the input terminal of the charging unit. Additionally, the connection between the charging connector and the output terminal of the power divider unit is interrupted by opening the second switch of the power divider unit. In the charging unit, the first DC voltage is converted to a higher second DC voltage by a DC-DC converter, and then this second DC voltage is switched to the output terminal of the power divider unit through the output terminal of the charging unit. Therefore, the energy storage device electrically connected to the output terminal can be charged with the second DC voltage.

[0046] Other advantages arise from the following description of the accompanying drawings. Embodiments of the invention are illustrated in the drawings. The drawings, description, and claims encompass a large number of combinations of features. Those skilled in the art will also find it desirable to individually observe the stated features and combine them into other meaningful combinations. Attached Figure Description

[0047] This is shown here:

[0048] Figure 1 This presents a system overview of a charging device for charging an electric energy storage device of an electrically powered vehicle according to an embodiment of the present invention.

[0049] Figure 2 A schematic diagram of a vehicle having a charging device according to the present invention is shown; and

[0050] Figure 3 A flowchart illustrating a method for charging an electric energy storage device for an electrically powered vehicle according to an embodiment of the present invention is shown. Detailed Implementation

[0051] In the accompanying drawings, identical or similar parts are given the same reference numerals. The drawings are for illustrative purposes only and should not be interpreted restrictively.

[0052] Figure 1 This presents a system overview of a charging device 100 for charging an electric energy storage device 60 of an electrically operable vehicle 200 according to an embodiment of the present invention.

[0053] The charging device 100 includes a charging connector 50 for electrically connecting the charging device 100 to an external voltage supply device (not shown), a charging unit 10 for converting a first DC voltage applied to the charging connector 50 into a second DC voltage, and a power divider unit 30, the second DC voltage being configured to charge an energy storage device 60. The power divider unit has first and second output terminals 36 and 38, which are used to provide the first DC voltage applied to the charging connector 50 and / or the second DC voltage converted by the charging unit 10 to the energy storage device 60, which is attached to the output terminals 36 and 38.

[0054] In the embodiment shown in the accompanying drawings, the energy storage unit 60 is directly attached to the output terminals 36, 38 of the power divider unit 30 and includes a row of battery elements 66, which are schematically indicated only by battery symbols and are connected for charging via two contactors 62, 64.

[0055] Generally, the output terminals 36 and 38 of the power divider unit 30 can be connected to another, not shown, charging-related component of the high-voltage intermediate circuit of the vehicle's high-voltage on-board network, such as another switch.

[0056] The power divider unit 30 has a first electrical connector 52 for the charging connector 50 and a second electrical connector 56 for the charging unit 10.

[0057] Furthermore, the power divider unit 30 has switches 32 and 34, which, in the first charging state, allow the charging connector 50 to be switched to the first and second output terminals 36 and 38 by closing the switches 32 and 34. Therefore, in the first charging state, the first DC voltage applied to the charging connector 50 is switched to the first and second output terminals 36 and 38 of the power divider unit 30.

[0058] The charging unit 10 has a connector 54 through which its input terminal 24 and two output terminals 20, 22 can contact the connector 56 of the power divider unit 30. The input terminal 24 of the charging unit 10 is interconnected with the second pole 42 of the charging connector 50. A switch 18 is provided in the charging unit 10, which connects the input terminal 24 of the charging unit 10 to the input terminal 26 of the DC-DC converter 12 of the charging unit 10. The DC-DC converter 12 is configured as a boost converter and has an input capacitor 14 at its input terminal and an output capacitor 16 at its output terminal. By connecting the output terminal 20 of the charging unit 10 to the output capacitor 16 and the input capacitor 14, the output terminal 20 also serves as the input terminal of the charging unit 10. Here, in this embodiment, a current-coupled DC-DC converter 12 is involved, having coupling in the upper path, i.e., in the plus path, to the output terminals 20, 22 and the input terminal 24, and the output terminal 20 as a simultaneous additional input terminal.

[0059] In a first charging state, specifically when the first DC voltage at the charging connector 50 is greater than or equal to the rated voltage of the energy storage device 60, the first switch 32 and the second switch 34 of the power divider unit 30 are closed, and the third switch 18 of the charging unit is open. Therefore, the first DC voltage is applied between the first output terminal 36 and the second output terminal 38 of the power divider unit 30, and the energy storage device 60 can be charged with the first DC voltage.

[0060] In the second charging state, the first output terminal 20 of the charging unit 10 is switched to one of the output terminals 36 and 38 of the power divider unit 30. Figure 1 In this embodiment, the second output terminal 22 of the charging unit 10 is switched to the other output terminal among the output terminals 36 and 38 of the power divider unit 30. Figure 1 The circuit switches to the second output terminal 38. As shown in the figure, this path can be protected by an optional safety device 46.

[0061] In a second charging state, particularly when the first DC voltage at the charging connector 50 is less than the rated voltage of the energy storage device 60, the first switch 32 is closed, thus interconnecting the first output terminal 20 of the charging unit 10 with the first pole 40 of the charging connector 50 and directly with the first output terminal 36 of the power divider unit 30 via the closed first switch 32 of the power divider unit 30. The second switch 34 of the power divider unit 30 remains open.

[0062] The second output terminal 22 of the charging unit 10 is fixedly interconnected with the second output terminal 38 of the power divider unit 30. Therefore, the input terminal 24 of the charging unit 10 is connected to the second pole 42 of the charging connector 50. The third switch 18 of the charging unit 10 is then closed. Therefore, the input terminal 26 of the DC-DC converter 12 is connected to the second pole 42 of the charging connector 50.

[0063] Therefore, in the second charging state, the first DC voltage applied to the charging connector 50 is directly applied to the DC voltage converter 12, and can be converted by the DC voltage converter into a second DC voltage. Then, the second DC voltage is switched to the first and second output terminals 36, 38 of the power divider unit 30. Thus, the energy storage device 60 can be charged with the second DC voltage.

[0064] Therefore, the positive terminal of the two poles 40, 42 of the charging connector 50, here pole 40, serves as a common reference in the second charging state for the first DC voltage applied to the charging connector 50 and the second DC voltage applied to the first output terminal 36 and the second output terminal 38 of the power divider unit 30. In this way, it is advantageously possible to interconnect the charging unit 10 and the power divider unit 30 via the three-pole connectors 54, 56.

[0065] With the aid of the charging device 100 according to the invention shown, for example, an energy storage device 60 with a rated voltage greater than 500V, for example 800V, can also be charged at a charging station with an output voltage of less than 500V, such as 400V.

[0066] If 800V is used as the first DC voltage at charging connector 50, the first DC voltage can be directly connected to the output terminals 36 and 38 of the power divider unit 30 in the first charging state and charge the energy storage device 60 with a high current, for example, 500A. For this purpose, the first electrical connector 52 of the power divider unit 30 has a two-pole high-current plug connector.

[0067] However, if only 400V is available as the first DC voltage at charging connector 50, this first DC voltage is not directly connected but is instead supplied to input terminal 26 of DC-DC converter 12, which converts the 400V first DC voltage to a second DC voltage of 800V. This second DC voltage of 800V is then switched to output terminals 36, 38 of power divider unit 30, thereby charging energy storage unit 60. This charging process can advantageously be performed with a lower current, for example, 125A for a charging power of 50kW, such that the two plug connectors 54, 56 between charging unit 10 and power divider unit 30 only require three-pole plug connectors with a lower nominal current for DC-DC converter 12.

[0068] Figure 2 A vehicle 200 having a charging device 100 according to the invention is shown in the schematic diagram. The vehicle 200 is shown in a top view. A charging connector 50 is drawn on the right rear side of the vehicle 200 in the drawing, which is electrically connected to a power divider unit 30. The power divider unit 30 has electrical connections to the charging unit 10 and the energy storage unit 60.

[0069] exist Figure 3 The diagram shows a flowchart of a method for charging an electric energy storage device 60 of an electrically operable vehicle 200 according to an embodiment of the present invention.

[0070] The method begins with the following steps: in step S100, a first DC voltage is determined to be applied to the charging connector 50, and in step S102, this first DC voltage is compared with the rated voltage of the energy storage device 60. Typically, the applied first DC voltage is determined based on communication between the vehicle and the charging station, in which the charging station transmits the maximum voltage it can provide as the first DC voltage to the vehicle.

[0071] If the first DC voltage is greater than or equal to the rated voltage of the energy storage device 60, for example, if the first DC voltage available at the charging connector 50 is 800V and the rated voltage of the energy storage device 60 is also 800V, then in step S104, the first and second switches 32 and 34 of the power divider unit 30 are closed to connect the charging connector 50 to the first output terminal 36 and the second output terminal 38 of the power divider unit 30.

[0072] Therefore, in step S106, the first DC voltage is switched to the first output terminal 36 and the second output terminal 38 via the first and second switches 32 and 34.

[0073] Therefore, in step S108, the energy storage device 60 can be charged with the first DC voltage.

[0074] If the first DC voltage available for use is less than the rated voltage of the energy storage device 60, for example, if the first DC voltage available for use at the charging connector 50 is 400V and the rated voltage of the energy storage device is 800V, then in step S110, the first switch 32 is closed to connect the first pole 40 of the charging connector 50 to the first output terminal 36 of the energy storage device and the first output terminal 20 of the charging unit 10.

[0075] In step S112, the second switch 34 of the power divider unit 30 remains open. The input terminal 24 of the charging unit 10 is connected to the second pole 42 of the charging connector 50. If the second switch 34 should have been closed in another step during the preparation phase of the method, the closed switch 34 is opened in step S112.

[0076] In step S114, the third switch 18 of the charging unit 10 is closed to connect the input terminal 24 of the charging unit 10 to the input terminal 26 of the DC voltage converter 12 of the charging unit 10.

[0077] Therefore, in step S116, the second DC voltage converted by the charging unit 10 is switched to the first output terminal 36 and the second output terminal 38 of the power divider unit 30.

[0078] Therefore, in step S118, the energy storage device 60 can be charged with the second DC voltage.

[0079] List of reference numerals

[0080] 10 charging units

[0081] 12 DC-DC voltage converter

[0082] 14 Input Capacitor

[0083] 16 Output capacitors

[0084] 18 switches

[0085] 20 First output terminal of charging unit

[0086] 22 Second output terminal of charging unit

[0087] 24. Input terminal of the charging unit

[0088] 26. Input terminal of DC-DC voltage converter

[0089] 30 power divider units

[0090] 32 switches

[0091] 34 Switches

[0092] The first output terminal of the 36 power divider unit

[0093] 38. Second output terminal of the power divider unit

[0094] 40 First Pole

[0095] 42 Second Pole

[0096] 46 Safety devices

[0097] 50 Charging connector

[0098] 52 High Current Connector

[0099] 54 Plug-in Connector

[0100] 56 Plug-in connector

[0101] 60 energy storage devices

[0102] 62 switches

[0103] 64 switches

[0104] 66 Battery Components

[0105] 100 charging equipment

[0106] 200 vehicles.

Claims

1. Charging device (100) for charging an electrical energy store (60) of an electrically operable vehicle (200), the charging device having - a charging connection (50) for electrically connecting the charging device (100) to an external voltage supply, - a charging unit (10) for converting a first direct voltage applied at the charging connection (50) into a second direct voltage, which is provided for charging the electrical energy store (60), - a power distributor unit (30) having first and second outputs (36, 38) for providing the first direct voltage applied at the charging connection (50) and / or the second direct voltage converted by the charging unit (10) to the electrical energy store (60) attached at the outputs (36, 38), the power distributor unit (30) having a first electrical connection (52) for the charging connection (50) and a second electrical connection (56) for the charging unit (10), - wherein the power distributor unit (30) has switches (32, 34) by means of which, in a first charging state, the charging connection (50) is switched onto the first and second outputs (36, 38), in a second charging state the first output (20) of the charging unit (10) is switched onto one of the outputs (36, 38) of the power distributor unit (30) and the second output (22) of the charging unit (10) is switched onto the other of the outputs (36, 38) of the power distributor unit (30), characterized in that, in the second charging state, the first output (20) of the charging unit (10) is interconnected via the first switch (32) of the power distributor unit (30) with the first pole (40) of the charging connection (50) and directly with the first output (36) of the power distributor unit (30), wherein the first output (20) of the charging unit (10) also simultaneously serves as an input of the charging unit (10) by virtue of the connection of the first output (20) of the charging unit (10) to the output capacitor (16) of the charging unit (10) and to the input capacitor (14) of the charging unit (10), the second output (22) of the charging unit (10) is interconnected with the second output (38) of the power distributor unit (30), the input (24) of the charging unit (10) is interconnected with the second pole (42) of the charging connection (50), wherein a switch (18) is provided in the charging unit (10), which switch connects the input (24) of the charging unit (10) to the input (26) of a direct voltage converter (12) of the charging unit (10), wherein the direct voltage converter (12) is configured as a step-up converter.

2. Charging device according to claim 1, ​ ​ - wherein, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ wherein In a first charging state, the first switch (32) and the second switch (34) are closed and the third switch (18) is open, wherein the first direct voltage is applied between the first output (36) and the second output (38) of the power distributor unit (30).

3. The charging device according to claim 1 or 2, wherein In the second charging state, the first direct voltage at the charging connection (50) is less than the rated voltage of the electrical energy store (60).

4. The charging device according to claim 1 or 2, wherein In the first charging state, the first direct voltage at the charging connection (50) is greater than or equal to the rated voltage of the electrical energy store (60).

5. The charging device according to claim 1 or 2, wherein, The first electrical connection (52) of the power distributor unit (30) has a two-pole high-current plug connector.

6. The charging device according to claim 1 or 2, wherein The second electrical connection (56) of the power distributor unit (30) has one three-pole plug connector or two plug connectors, one with one pole and one with two poles.

7. The charging device according to claim 1 or 2, wherein, At the charging unit (10), a third electrical connection (54) is provided, which is attached at the second electrical connection (56) of the power distributor unit (30), wherein the third electrical connection (54) has one three-pole plug connector or two plug connectors, one with one pole and one with two poles.

8. The charging device according to claim 7, characterized in that The second electrical connection (56) of the power distributor unit (30) and the third electrical connection (54) of the charging unit (10) are embodied complementarily, such that the second electrical connection (56) of the power distributor unit (30) can be connected directly to the third electrical connection (54) of the charging unit (10) without a connecting device.

9. The charging device according to claim 1 or 2, wherein, In the second charging state, the positive pole of the poles (40, 42) of the charging connection (50) is the common reference for the first direct voltage applied at the charging connection (50) and the second direct voltage applied at the first output (36) and the second output (38) of the power distributor unit (30).

10. Method for charging an electrical energy store (60) of an electrically operable vehicle (200) by means of a device (100) according to any one of the preceding claims 1 to 9, the method comprising at least the following steps: - comparing a first direct voltage, which can be provided at a charging connection (50), with a rated voltage of the electrical energy store (60); - if the first direct voltage is greater than or equal to the rated voltage of the electrical energy store (60), - applying the first direct voltage at the charging connection (50) and the second direct voltage at the first output (36) and the second output (38) of the power distributor unit (30). o closing the first and second switches (32, 34) of the power distributor unit (30) for connecting the charging terminal (50) with the first output (36) and the second output (38) of the power distributor unit (30); o switching the first DC voltage via the first and second switches (32, 34) to the first output (36) and the second output (38); o charging the electrical energy reservoir (60) with the first DC voltage; - if the first DC voltage is smaller than the rated voltage of the electrical energy reservoir (60), o closing the first switch (32) for connecting the first pole of the charging terminal (50) with the first output (36) of the electrical energy reservoir and the first output (20) of the charging unit (10); o keeping the second switch (34) of the power distributor unit (30) open or opening and connecting the input (24) of the charging unit (10) with the second pole of the charging terminal (50); o closing the third switch (18) of the charging unit (10) for connecting the input (24) of the charging unit (10) with the input (26) of the DC voltage converter (12) of the charging unit (10), which is configured as a step-up converter; o switching the second DC voltage converted by the charging unit (10) to the first output (36) and the second output (38) of the power distributor unit (30); o charging the electrical energy reservoir (60) with the second DC voltage.

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