CN111169300A

CN111169300A - Device for charging a battery of an electrically driven motor vehicle

Info

Publication number: CN111169300A
Application number: CN201911093255.6A
Authority: CN
Inventors: R.芬尼格沃思; C.布塞; K.罗沃尔德
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2018-11-12
Filing date: 2019-11-11
Publication date: 2020-05-19
Also published as: DE102018219296A1

Abstract

The invention relates to a device (2) for charging a battery (4) of an electrically driven motor vehicle (6), wherein the device (2) has a first plug element (8) with an AC contact (12). ), the first plug element (8) is used for connection to the domestic grid (20), the device (2) also has a second plug element (14) with a DC contact (18), the second plug The element (14) is used to input the charging DC voltage (U _DCL ) into the battery (4) of the motor vehicle (6), and the device (2) also has a connection between the AC contact (12) and the DC contact (18) There is a voltage transformer (26) in between, the voltage transformer (26) being used to convert the alternating voltage (U _AC ) provided by the domestic power grid ( 20 ) into the charging direct current voltage (U _DCL ).

Description

Device for charging a battery of an electrically driven motor vehicle

Technical Field

The invention relates to a device for charging a battery of an electrically driven motor vehicle, wherein the device has a first plug element and a second plug element.

Background

Electrically driven motor vehicles typically have a battery (traction battery) which supplies the electric motor for driving the motor vehicle with energy. Electrically driven vehicles are understood here to mean, in particular, electric vehicles (BEV), extended-range electric vehicles (REEV), Hybrid Electric Vehicles (HEV) and/or plug-in hybrid electric vehicles (PHEV) in which the energy required for driving is stored exclusively in the battery.

For charging the battery, for example, the battery charging system of the motor vehicle is connected to an ac power supply, also referred to as a charging wall box. Alternatively, the battery charging system of the motor vehicle is connected via a charging cable to a supply network which supplies an alternating voltage. The battery charging system of a motor vehicle has a charging device, also referred to as an on-board charger, which converts an incoming ac voltage into a charging dc voltage suitable for charging the battery. The disadvantage is that the vehicle-mounted charger is only carried along when the motor vehicle is running, so that the vehicle-mounted charger usually does not perform other functions than charging with direct current. Furthermore, since heat is generated during operation of such a vehicle charger, the vehicle charger needs to be additionally cooled, which results in a relatively high manufacturing cost and requires additional installation space.

Instead of charging the battery with ac voltage, a dc charging device is used. Such a dc charging device provides a charging dc voltage suitable for charging a battery. In this case, the charging dc voltage is not supplied to the vehicle-mounted charger, but rather directly to the battery, in particular via a dc charging interface of the battery charging system. Such a dc charging device can provide a relatively high charging power. In this case, however, such a dc charging device is relatively heavy, so that it is, for example, fixed to a wall or mounted upright on itself. Furthermore, the availability of such dc charging devices is relatively low, especially in rural areas. It may therefore not be possible or at relatively high expenditure for the user to charge the battery with such a dc charging device.

Disclosure of Invention

The technical problem forming the basis of the present invention is to provide a device suitable for charging a battery of an electrically driven motor vehicle. Such a device should in particular be transportable and/or be as simple to handle as possible. The dc voltage is to be supplied to a battery charging system of the motor vehicle.

The object is achieved according to the invention by a device for charging a battery of an electrically driven motor vehicle. The device has a first plug element with alternating current contacts for connection to a domestic network; the device has a second plug element with a DC contact for supplying a charging DC voltage to a battery of the motor vehicle; and the device has a voltage transformer connected between the ac contact and the dc contact for converting an ac voltage provided by the domestic power network into the charging dc voltage.

The device is used for charging a battery of an electrically driven motor vehicle. For this purpose, the device has a first plug element with alternating current contacts. The first plug element is provided and intended for connection to a domestic power supply system, in particular to a connection terminal of the domestic power supply system, which is designed as a socket. The device also has a second plug element with a dc contact, by means of which a charging dc voltage can be supplied to the battery of the motor vehicle. The second plug element is provided and arranged for being connected to a direct current charging interface of a battery charging system of an electrically driven motor vehicle. The second plug element is preferably designed such that it complies with the applicable standards and regulations, for example the ISO standard. For example, the second plug element is designed as a so-called CSS plug (combined charging system plug) or as a CHAdeMO plug.

In summary, an electrical connection to the domestic power supply system is established by means of the first plug element and an electrical connection to a dc charging interface of a battery charging system of the motor vehicle is established by means of the second plug element.

The device also has a voltage transformer or voltage converter connected between the ac contact and the dc contact. The voltage transformer is used for converting alternating current voltage provided by a household power grid into charging direct current voltage.

The domestic network is also referred to as a low-voltage network, for example. In particular, the household electrical system is a three-phase ac system, wherein one phase of the three-phase ac system is fed into a first plug element connected to the household electrical system. For example, the ac voltage of a domestic power network in germany has an effective value of 230V and a frequency of 50 Hz.

The availability of the domestic power grid is relatively high. The connection to the domestic power supply is therefore relatively widely used and almost universally available, in particular in comparison with the availability of the dc charging device mentioned at the outset. Thus, charging the battery of the motor vehicle with the device can be achieved relatively easily and is therefore comfortable for the user.

Since the ac voltage supplied by the domestic power supply system is converted into a dc voltage by means of such a device, it is no longer necessary to convert the voltage by means of an on-board charger of the battery charging system of the motor vehicle. Accordingly, the battery charging system of an electrically driven motor vehicle preferably has no on-board charger, in particular if the (charging) power level of the on-board charger corresponds to the charging power that can be achieved with the device.

According to a suitable embodiment, the voltage transformer has a rectifier and a voltage regulator. The rectifier is preferably designed as a so-called power factor correction filter. In this case, an ac voltage is fed to the rectifier on the input side, which is converted into a dc voltage by means of the rectifier. The rectifier is connected on the output side to a voltage regulator, which converts the dc voltage input from the rectifier into a charging dc voltage. The voltage regulator is preferably designed as a buck regulator (tiefsetzteller). The voltage regulator regulates the charging dc voltage to a voltage value suitable for charging the battery, which is dependent in particular on the charging state of the battery. That is, a voltage transformer designed as a buck regulator reduces the dc voltage accordingly.

According to an advantageous embodiment, the dc contact of the second plug element is electrically isolated from the voltage transformer by means of a transformer (galvanosche Trennung). In this way, the potentials of the two current loops formed as a result of the galvanic isolation are isolated from one another. In this case, an inverter is expediently connected between the transformer and the voltage transformer, in order to be able to achieve induction at the transformer. A further rectifier is connected between the transformer and the dc contacts in order to convert the induced ac voltage back into a charging dc voltage.

For example, the device additionally has elements for insulation measurement, by means of which the electrically isolated insulation effect can be checked with respect to its safety or non-malfunction.

According to an advantageous embodiment of the device, the dc contact is connected to a discharge circuit. The dc contacts can be switched by means of the discharge circuit to a voltage-free or voltage-free connection with respect to one another. In particular, the discharge circuit has a discharge resistor for this purpose, which electrically connects the two dc contacts via a controllable switch. In particular, if the device is not connected to a battery charging system of a motor vehicle, the dc contacts should be voltage-free, i.e. have the same (electrical) potential, relative to one another for the safety of a user of the device. For this purpose, the switch is closed, i.e. switched to conduct (current), so that the two dc contacts are electrically connected to one another via the discharge resistor. If the device is connected to a battery charging system of a motor vehicle, the switch is opened, i.e. switched to interrupt the current, so that the connection of the two dc contacts via the discharge resistor is broken.

According to an advantageous further development, the device has a control device for controlling the discharge circuit, in particular the switches of the discharge circuit.

In addition or alternatively, the control device is used to control a voltage transformer, in particular a voltage regulator, in order to regulate the charging dc voltage to a voltage value suitable for charging the battery, which voltage value is selected in particular in accordance with the state of charge of the battery of the motor vehicle. In this case, the charging dc voltage is regulated, for example, in accordance with the DIN standard, in accordance with the rated charging current, the rated power or the rated charging dc voltage which is to be supplied to the battery charging system. For this purpose, the charging current supplied to the battery charging system is measured by means of the device and the charging DC voltage or the charging current is adjusted in accordance with the selected adjustment method.

In addition or alternatively, the control device is used for communication with a control unit of the battery charging system, which is also referred to as a battery management system. For example, the second plug element has for this purpose, in addition to the direct-current contacts, further contacts, which are also referred to as communication contacts or Pilot lines (Pilot-leitsung). The battery charging system expediently has corresponding communication connections for the communication contacts, which are in turn connected to a control unit of the battery charging system. In this way, control signals, fault signals and/or data may be exchanged between the control device and the control unit of the battery charging system.

Alternatively, the communication between the control device and the control unit is performed wirelessly. For this purpose, the device has a receiving and transmitting unit connected to the control device, by means of which data and/or signals can be transmitted by radio to the respective receiving and transmitting unit connected to the control unit.

According to a suitable embodiment, the device has a disconnection device (disconnector) which disconnects the ac contact from the voltage transformer (electrically) as a function of the control signal output by the control device. The disconnecting means is constituted by a switch, for example. In this way, the input of the charging dc voltage to the battery charging system can be interrupted. Such a control signal is output in particular if the charging process ends or if a fault occurs during the communication or in the charging process itself.

According to a suitable further development, the device has a residual current device (residual current device) which disconnects the ac contacts from the voltage transformer in the event of a fault. In other words, the electrical connection of the domestic electrical system, i.e. the interruption of the electrical connection of the voltage transformer to the ac contact of the first plug element, is interrupted by means of the residual current circuit breaker. In summary, fault current circuit breakers are used to open a circuit on the network side (infrastructure side) in the event of a fault. A fault situation is understood here to mean, in particular, that the charging current exceeds a predetermined threshold value.

According to an advantageous embodiment, the device has an interference suppression filter (power filter) which is connected to the input of the voltage transformer. In this way, the electromagnetic compatibility of the device, in particular of the voltage transformer, against interference from the domestic power supply network is improved. In other words, the noise immunity of the device, in particular of the voltage transformer, is increased. Furthermore, radio interference resistance is achieved, i.e. electrical interference from the device, in particular from the voltage transformer, to the domestic power supply system is reduced or even prevented.

According to an advantageous embodiment, the control unit, the voltage transformer, the discharge circuit, the residual current circuit breaker, the disconnection device and/or the interference suppression filter are arranged in the housing of the first plug element or alternatively in the housing of the second plug element. In this way, at least one of these components is integrated in the first plug element or in the second plug element. The two plug elements are preferably connected to one another by means of a connecting line.

Alternatively, the first plug element and the second plug element have a common housing, so that the device is designed particularly compact and easy to operate. In this case, the above-described plurality of components are arranged in a common housing.

According to a suitable embodiment, a display element and, additionally or alternatively, an operating element are integrated in the housing, in which the respective components are integrated. For example, the display element is designed as an LED or display, by means of which, for example, fault codes can be output or status can be displayed. The operating element is designed, for example, as a switch or a push button, by means of which the charging process of the battery can be started and/or ended, or alternatively one of the above-described adjustment modes can be selected.

Suitably, the display element or the operating element is connected to the control device.

Drawings

Embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the drawings:

fig. 1 shows a device for charging a battery of an electrically driven motor vehicle, wherein the device has a first plug element with an ac contact and a second plug element with a dc contact, and wherein the ac contact and the dc contact are connected by a voltage transformer, and

fig. 2 shows the device, wherein a first plug element is provided and arranged for connection to a domestic network and a second plug element is provided and arranged for connection to a dc charging interface of a motor vehicle.

Parts and dimensions corresponding to one another are always provided with the same reference numerals in all figures.

Detailed Description

Fig. 1 shows a device 2 for charging a battery 4 of an electrically driven motor vehicle 6. The device 2 has a first plug element 8 with two ac contacts 12. Furthermore, the device 2 has a second plug element 14, which second plug element 14 has a housing 16 and two dc contacts 18.

The first plug element 8 is intended for connection to a domestic electrical system 20, and the second plug element is intended for connection to a dc charging interface 22 of a battery charging system 24 of the motor vehicle 6 (see fig. 2).

A voltage transformer 26 is arranged in the second housing 16 of the second plug element 14, which voltage transformer 26 is connected between the ac contact 12 and the dc contact 18. The voltage transformer 26 has a rectifier 28, which is designed as a power factor correction filter, and a voltage regulator 30. An alternating voltage U, for example with a magnitude of 230V, of the domestic power supply system 20 is supplied by means of a rectifier 28_ACRectified to a DC voltage U of, for example, 450V_DC. For this purpose, the rectifier 28 is electrically connected on the input side to the ac contact 12. That is, the voltage transformer 26 is electrically connected at its input end to the ac contact 12. The rectifier 28 is connected on the output side to a voltage regulator 30 designed as a step-down regulator, wherein the dc voltage U output by the rectifier is connected_DCIs regulated in a reduced manner by means of a voltage regulator 30 to a charging DC voltage U suitable for charging a battery_DCL. For example, charging DC voltage U_DCLIn particular with the charging of the battery 4The state dependence is 220 to 450V.

A transformer 32 is also connected between the voltage regulator 30 of the voltage transformer 26 and the dc contact 18, said transformer 32 electrically isolating the dc contact 18 from the voltage transformer 26. Here, in order to achieve induction in the transformer 32, the inverter 34 is connected between the transformer 32 and the voltage regulator 30 of the voltage transformer 26, and the inverter 34 charges the dc voltage U_DCLConverted into an alternating voltage. On the direct-current contact side, the transformer 32 is connected to a second rectifier 36, and the second rectifier 36 converts the alternating-current voltage induced on the direct-current contact side back to a charging direct-current voltage U_DCL. The second rectifier 36 is connected to the dc contact 18.

The two dc contacts 18 can be connected to one another in a voltage-free manner by means of a discharge circuit 38. For this purpose, the discharge circuit 38 has a discharge resistor 40 and a first switch 42, wherein the discharge resistor 40 and the first switch 42 are connected in series with the two dc contacts 18. For example, if the device 2 is not connected to the dc charging interface 22 of the battery charging system 24, the dc contacts 18 of the device 2 should be voltage-free with respect to each other for the safety of the user of the device 2. For this purpose, the first switch 42 is closed, i.e. the first switch 42 is switched to conducting current, so that the two dc contacts 18 are electrically connected to one another via the discharge resistor 40. The device 2 has a control device 44, which control device 44 is connected to the first switch 42 in order to open or close the first switch 42.

Furthermore, the control device 44 is connected to a communication contact 46. The communication contact 46 is used for communication with a control unit 48 of the battery charging system 24 comprising the battery 4. The battery charging system 24 has corresponding communication connections 47 for the communication contacts 46. The communication connection 47 is in turn connected to a control unit 48 of the battery charging system 24, so that control signals, fault signals and/or data can be exchanged between the control device 44 and the control unit 48 of the battery charging system 24. The battery charging system 24 has a second switch 50 as a protection device, by means of which the battery 4 can be disconnected from the dc charging interface 22 if, for example, corresponding signals are fed from the control device 44 to the control unit 48 by means of the communication contact 46 and the communication connection 47 or if a fault occurs during communication or during charging.

The second plug element 14 also has two operating elements 52 and a display element 54 designed as a display. The operating element 52 and the display element 54 are integrated in the housing 16 and are each connected to the control device 44. By means of the display element 54, a fault code or a display status can be output. The operating element 52, which is designed here as a push button, is used, for example, to start or end a charging process of the battery 4.

Furthermore, the control device 44 is connected to a disconnection device 56 designed as a third switch. In this case, the third switch is connected between one of the ac contacts 12 and the voltage transformer 26. The ac contact 12 is disconnected from the voltage transformer 26 by opening the third switch, i.e., switching the third switch to interrupt the current, in response to the control signal S output by the control device 44.

For supplying the control device 44, said control device is connected to the ac contact 12 via a second transformer 58.

A fault current protection switch 60 and an interference suppression filter 62 are also connected between the ac contact 12 and the voltage transformer 26. The residual current circuit breaker 60 disconnects the ac contact 12 from the voltage transformer 26 in the event of a fault, in particular if the charging current flowing through the residual current circuit breaker 60 exceeds a threshold value when the battery 4 is charged. The interference suppression filter 62 is used to improve the electromagnetic compatibility of the device 2.

The first plug element 8 and the second plug element 14 each have a safety terminal 64, the safety terminals 64 being connected to one another by means of a safety line (Schutzleitung) 66.

The first plug element 8 and the second plug element 14 are connected by means of a connecting line 68, the connecting line 68 comprising a safety lead 66 and a conductor leading from the ac contact 12 to the dc contact 18. The connecting line 68 is shown here shortened for the sake of clarity.

Fig. 2 shows a motor vehicle 6 having a battery charging system 24. The battery charging system 24 comprises a control unit 48, a second switch 50, the battery 4, the communication connection 47 and the dc charging interface 22. The dc contact 18 and the communication contact 46 of the second plug element are provided for connection to a dc charging interface or communication connection 47 of the battery charging system 24. The first plug element 8 is intended for connection to a domestic electrical system 20 by means of a socket 70.

The safety terminal 64 is not further shown in fig. 2.

The present invention is not limited to the above-described embodiments. But other variations of the invention can be derived therefrom by those skilled in the art without departing from the invention. Furthermore, in particular, all individual features described in connection with the exemplary embodiments can also be combined with one another in different ways, without departing from the scope of the invention.

List of reference numerals

2 device

4 cell

6 Motor vehicle

8 first plug element

12 AC contact

14 second plug element

16 casing

18 D.C. contact

20 household electric network

22 DC charging interface

24 battery charging system for motor vehicle

26 voltage transformer

28 rectifier

30 voltage regulator

32 transformer

34 inverter

36 second rectifier

38 discharge circuit

40 discharge resistance

42 first switch

44 control device

46 communication contact

47 communication connection terminal

48 control unit

50 second switch

52 operating element

54 display element

56 disconnecting device

58 second transformer

60 fault current protection switch

62 interference rejection filter

64 safety lead connector

66 safety lead

68 connecting line

70 socket

U_ACAlternating voltage

U_DCDirect voltage

U_DCLCharging DC voltage

S control signal

Claims

1. A device (2) for charging a battery (4) of an electrically driven motor vehicle (6), the device (2) having

- a first plug element (8) with an AC contact (12) for connection to the domestic grid (20);

- a second plug element (14) with a DC contact (18) for supplying a charging DC voltage (U _DCL ) to the battery (4) of the motor vehicle (6); and

- a voltage transformer (26) connected between said AC contact (12) and DC contact (18), said voltage transformer (26) for converting the AC voltage (U) provided by the domestic grid (20) _AC ) is converted into the charging DC voltage (U _DCL ).

2. The device (2) according to claim 1, characterized in that,

The voltage transformer (26) has a rectifier (28) in particular designed as a power factor correction filter and a voltage regulator (30), wherein the rectifier (28) is supplied on the input side with an alternating voltage (U _AC ) , and wherein the rectifier (28) is connected to a voltage regulator (30) at the output side, and the voltage regulator (30) converts the DC voltage (U _DC ) input from the rectifier into a charging DC voltage (U _DCL ) .

3. The device (2) according to claim 1 or 2, characterized in that,

The DC contact (18) is electrically isolated from the voltage transformer (26) by means of a transformer (32).

4. The device (2) according to any one of claims 1 to 3, characterized in that,

The DC contacts (18) are connected to a discharge circuit (38), by means of which the DC contacts (18) can be switched to be voltage-free relative to each other.

5. The device (2) according to any one of claims 1 to 4, characterized in that,

A control device (44) for a voltage transformer (26) and/or a discharge circuit (38) is provided for charging a battery of a motor vehicle (6) including the battery (4) The control unit (48) of the system (24) communicates.

6. The device (2) according to claim 5, characterized in that,

A disconnecting device (56) is provided, which disconnects the AC contact (12) from the voltage transformer (26) according to a control signal (S) output by the control device (44).

7. The device (2) according to any one of claims 1 to 6, characterized in that,

A fault current protection switch (60) is provided which disconnects the AC contact (12) from the voltage transformer (26) in the event of a fault.

8. The device (2) according to any one of claims 1 to 7, characterized in that,

An interference suppression filter (62) is provided, and the interference suppression filter (62) is connected to the input end of the voltage transformer (26).

9. Device (2) according to any of the preceding claims, characterized in that,

The control unit (48), the voltage transformer (26), the discharge circuit (38), the fault current protection switch (60), the disconnecting device (56) and/or the interference suppression filter (62) are arranged at the first plug element (8) or the housing (GH) of the second plug element (14).

10. The device (2) according to claim 9, characterized in that,

The display element ( 54 ) and/or the operating element ( 52 ) are integrated in the housing (GH).