DE102016015316A1 - On-board DC charging device for a vehicle - Google Patents

Abstract

The invention relates to an on-board DC charging device (8) for a vehicle (1). According to the invention, two parallel electrical connection branches (Z1, Z2) are provided between a charge-side input (E) and a battery-side output (A), the one connection branch (Z1) providing a direct electrical connection between a charging socket (5) of the vehicle (1) and a battery (3) of the vehicle (1) and in the other connection branch (Z2) a DC-DC converter (7) is arranged and wherein a switching unit (9) for closing the one connection branch (Z1) or the other connection branch (Z2) is provided ,

Description

The invention relates to an on-board DC charging device for a vehicle according to the features of the preamble of claim 1.

Vehicles with at least one electric drive motor for driving the vehicle and a battery, also referred to as a traction battery, for providing electrical energy for this drive motor are known from the prior art. If charging of the battery is provided by means of an external electric power source, for example a charging station, these vehicles have an on-board DC charging device for charging the battery to the vehicle-external electric power source.

Furthermore, in the DE 10 2010 041 253 A1 a DC charging station for a battery of an electric vehicle described. The DC charging station has an AC-DC converter as a DC voltage source, at the output of which a controllable DC voltage can be made available with the aid of which the battery can be recharged. Between the output of the inverter and the output terminal of the DC charging station, a voltage adjustment unit is connected, which has a controllable switch, with which the connection between the voltage source and the battery can be selectively established or interrupted. The switch is controlled in response to the input and output side voltage of the voltage balancing unit to break the connection before and while the battery is connected to the DC output terminal, and makes a connection only when the input side voltage of the voltage balancing unit in Substantially corresponds to the output voltage of the voltage adjustment unit.

The invention is based on the object of specifying an improved over the prior art on-board DC charging device for a vehicle.

The object is achieved by an on-board DC charging device for a vehicle with the features of claim 1.

Advantageous embodiments of the invention are the subject of the dependent claims.

In an on-board DC charging device for a vehicle according to the present invention, i. H. in an arranged in the vehicle or can be arranged electric charging device for direct current charging on a DC electric power available external vehicle electrical energy source, for example, at a charging station, two parallel electrical connection branches are provided between a load-side input and a battery-side output, wherein a connecting branch is a direct electrical Connection between a charging socket of the vehicle and a battery of the vehicle allows and in the other connection branch a DC-DC converter is arranged and wherein a switching unit is provided for closing the one connection branch or the other connection branch.

The solution according to the invention makes it possible to charge the battery of the vehicle both at charging stations whose electrical voltage, d. H. their charging voltage corresponding to the electrical voltage of the battery, in particular over 400 V, for example, 800 V, as well as to load charging stations, the electrical voltage, d. H. whose charging voltage differs from the electrical voltage of the battery, for example, is smaller than the voltage of the battery, and for example, 400 volts. This also makes it possible to use in the vehicle batteries with a high electrical voltage level, for which there is no associated charging infrastructure with the same voltage level, since such batteries can be loaded by means of the inventive solution to existing charging stations with a lower voltage level.

The solution according to the invention makes it possible to directly charge the battery at a charging station with the same voltage level without a complex switching matrix since a direct electrical connection is made possible here via the one electrical connection branch which has no DC-DC converter. Furthermore, as already described, the solution according to the invention makes it possible to charge the battery at charging stations with a different voltage level via the other electrical connection branch to the DC-DC converter.

Embodiments of the invention are explained in more detail below with reference to drawings.

Showing:

1 a schematic representation of a vehicle with an embodiment of an electrical system,

2 a schematic representation of an electrical interconnection in a battery of the electrical system according to 1 for charging the battery with a high voltage,

3 a schematic representation of an electrical interconnection in a battery of the electrical system according to 1 for charging the battery with a low voltage,

4 a schematic representation of an electrical interconnection in a battery of the electrical system according to 1 for an electric driving operation of the vehicle, and

5 a schematic representation of a vehicle with another embodiment of an electrical system.

Corresponding parts are provided in all figures with the same reference numerals.

1 shows a schematically simplified view of a vehicle 1 with an embodiment of an electrical system 2 , which in particular an electric driving operation of the vehicle 1 allows. The vehicle 1 is thus designed, for example, as an electric vehicle, a hybrid vehicle or a fuel cell vehicle. It has a battery 3 , in particular a high-voltage battery, ie an electrochemical energy store, for providing electrical energy for at least one electric drive motor 4 to drive the vehicle 1 on. Such a battery 3 is also referred to as a traction battery. The electric drive motor 4 is in 1 not shown, but in 5 which a vehicle 1 with a further embodiment of the electrical system described later 2 shows.

For electrical charging of the battery 3 with an electrical DC voltage as a charging voltage to a vehicle external electrical energy source, such as a charging station, not shown, the vehicle 1 a charging socket 5 on, about which the electrical system 2 is electrically coupled with the vehicle external electrical energy source. For safety reasons, two switches S1, in particular electric contactors, are provided here, hereinafter referred to as charging contactors S1. The electrical system 2 according to 1 allows the battery 3 optionally to charge with a high charging voltage of, for example, 800 V, which corresponds to a battery voltage, or to charge with a low charging voltage, which corresponds to half the battery voltage, so for example 400 V. This is made possible by the formation of the battery 3 from two battery parts 03.01 . 3.2 , Also referred to as battery strings, which can be electrically interconnected in different ways.

2 shows an electrical connection in the battery 3 to charge the battery 3 with the high charging voltage, for example with 800 V. 3 shows an electrical connection in the battery 3 to charge the battery 3 with the low charging voltage, for example with 400 V. 4 shows an electrical connection in the battery 3 for an electric driving operation of the vehicle 1 , ie for an electrical power supply of the at least one electric drive motor 4 of the vehicle 1 , with a low electrical DC voltage of 400 V, for example, as a high-voltage vehicle electrical system 6 of the vehicle 1 , which the at least one electric drive motor 4 includes, is designed for this low electrical DC voltage as the vehicle electrical system voltage.

To these three modes according to the 2 to 4 to allow, includes the battery 3 an extensive switching matrix, also referred to as switching matrix, with seven internal battery switches BS1 to BS7, hereinafter referred to as battery switch BS1 to BS7. These battery switches BS1 to BS7 are expediently designed in each case as an electrical contactor. The switching matrix or switching matrix is therefore also referred to as a contactor matrix.

To charge the battery 3 with the high charging voltage of, for example, 800 V, which corresponds to the battery voltage, these battery switches BS1 to BS7 are switched such that the two battery parts 03.01 . 3.2 electrically connected in series with the charging socket 5 are coupled, as in 2 shown so on both battery parts 03.01 . 3.2 Half of the high charging voltage drops. For this purpose, in the illustrated embodiment, the first, third, fourth and sixth battery switches BS1, BS3, BS4, BS6 are opened and the second, fifth and seventh battery switches BS2, BS5, BS7 are closed.

To charge the battery 3 with the low charging voltage equal to half the battery voltage, these battery switches BS1 to BS7 are switched so that the two battery parts 03.01 . 3.2 electrically connected in parallel with the charging socket 5 are coupled, as in 3 shown so on both battery parts 03.01 . 3.2 the low charging voltage drops. For this purpose, in the illustrated embodiment, only the fifth battery switch BS5 is opened and the first, second, third, fourth, sixth and seventh battery switches BS1, BS2, BS3, BS4, BS6, BS7 are closed.

For the electric driving of the vehicle 1 requires the high-voltage on-board electrical system 6 of the vehicle 1 , as already mentioned, as the vehicle electrical system voltage, the low electrical DC voltage of, for example, 400 V. For this purpose, the battery switches BS1 to BS7 are switched such that the two battery parts 03.01 . 3.2 , electrically connected in parallel with the high-voltage vehicle electrical system 6 of the vehicle 1 are coupled, as in 4 shown. For this purpose are at In the illustrated embodiment, the first, second, third, fourth and sixth battery switches BS1, BS2, BS3, BS4, BS6 are closed and the fifth and seventh battery switches BS5, BS7 are opened.

To even while charging the battery 3 with the high charging voltage, the high-voltage on-board electrical system 6 of the vehicle 1 to be able to supply with electrical energy, has the electrical system 2 also a DC-DC converter 7 on which with the charging socket 5 is connected and to the battery 3 electrically connected in parallel. This DC-DC converter 7 , also referred to as a DC-DC converter, transforms the high charging voltage of, for example, 800 V down to the low vehicle electrical system voltage of, for example, 400 V.

The electrical system 2 of the vehicle 1 according to 1 with its different interconnection options according to the 2 to 4 allows charging the battery 3 with a high charging voltage of, for example, 800 V, which compared to the store with the usual low charging voltage of, for example, 400 V, an increased charging power and thus a lower charging time is achieved. Charging the battery 3 however, with the low charging voltage remains possible. To make this possible, there are no changes to components of the high-voltage vehicle electrical system 6 required. However, there are changes to charge the battery 3 required components required. In particular, the extensive contactor matrix is required to keep the battery parts 03.01 . 3.2 ie the strands of the battery 3 to switch depending on the respective operating mode. As electrical requirements are also a potential separation between the high charging voltage of, for example, 800 V and the low vehicle electrical system voltage of, for example, 400 V and thus a corresponding insulation coordination and as an additional component of the isolated DC-DC converter 7 required, which is designed for example to a power of 15 kW.

5 shows a schematically simplified view of a vehicle 1 with a further embodiment of such an electrical system 2 which in particular the electrical driving operation of the vehicle 1 allows. This in 5 illustrated electrical system 2 points opposite to in the 1 to 4 illustrated and described above electrical system 2 considerable advantages, as explained below. The vehicle 1 is here also, for example, as an electric vehicle, a hybrid vehicle or a fuel cell vehicle formed.

To provide electrical energy for at least one electric drive motor 4 to drive the vehicle 1 it also has a battery 3 , in particular a high-voltage battery, that is to say an electrochemical energy store, also referred to as traction battery. This battery 3 is however opposite to in the 1 to 4 illustrated embodiment much simpler, since the extensive switching matrix or contactor matrix with many in or on the battery 3 built mechanical components and the complex operation of the battery described above 3 in different modes, what the battery is for 3 must also have an electrical center tap, is not required. This achieves a significant cost reduction and complexity reduction. Nevertheless, this embodiment of the electrical system also allows 2 loading the vehicle 1 both with a high charging voltage which corresponds to the battery voltage, in particular more than 400 V, for example 800 V, as well as with a deviating, in particular lower, charging voltage of, for example, 400 V.

To make this possible is an on-board DC charging device 8th for the vehicle 1 provided, ie one in the vehicle 1 arranged electric charging device for direct current charging at a electric DC voltage-providing external vehicle electrical energy source, for example at a charging station, including this embodiment of the vehicle 1 the charging socket 5 For electrical coupling with the vehicle external electrical power source.

In this on-board DC charging device 8th are provided between a load-side input E and a battery-side output A two parallel electrical connection branches Z1, Z2. The first connection branch Z1 allows a direct electrical connection between the charging socket 5 of the vehicle 1 and the battery 3 of the vehicle 1 , In the second connection branch Z2, which forms a bypass to the first connection pointer Z1, is a DC-DC converter 7 arranged, that is also here, as well as in the above in the 1 to 4 described another embodiment, a DC-DC converter 7 provided, which, however, assumes another task here, as will be described below.

Furthermore, a switching unit 9 for switching between the connection branches Z1, Z2 and thus for closing the first connection branch Z1 or the second connection branch Z2 provided, ie for electrically connecting the first connection branch Z1 or the second connection branch Z2 with the load side inlet E and thus with the charging socket 5 of the vehicle 1 , Advantageously, this switching unit comprises 9 at least one switch S1, s2 in each of the two connection branches Z1, Z2, these switches S1, S2 are expediently designed in each case as an electrical contactor. In the example shown here, in the first connection branch Z1 as switch S1, the charging contactors S1 already described above and in the second connecting branch Z2 the further switches S2, hereinafter referred to as further charging contactors S2, are present.

This solution thus allows the battery 3 of the vehicle 1 to charge both external to the vehicle energy sources, in particular charging stations, the charging voltage of the battery voltage of, for example, 800 V, as well as to external vehicle energy sources, in particular charging stations to load, the charging voltage of the battery voltage deviates, for example, less than the battery voltage, for example only 400 V, or for example greater than the battery voltage. This also makes it possible in the vehicle 1 batteries 3 to use with a high electrical voltage level of, for example, 800 V, for which there is no associated charging infrastructure with the same voltage level, since such batteries 3 by means of this solution can also be loaded on existing charging stations with a lower voltage level.

The described and in 5 exemplified schematically solution allows the direct charging of the battery 3 at a vehicle external power source, in particular charging station, with the same voltage level, for example with a charging voltage of 800 V, without a complex switching matrix, since a direct electrical connection via the first electrical connection branch Z1 is made possible here. Furthermore, this solution, as already described, allows the charging of the battery 3 at external power sources, in particular charging stations, with a different voltage level, for example with a lower charging voltage of, for example, 400 V or with a higher charging voltage, via the second electrical connection branch Z2 with the DC-DC converter 7 , in which case the charging voltage by means of the DC-DC converter 7 is transformed to the battery voltage, that is correspondingly highly transformed at a lower charging voltage and is transformed down accordingly at a higher charging voltage, because the DC-DC converter 7 is for transforming, ie up-transforming or stepping down, one of the charging voltage of the charging station on the deviating, ie higher, or lower, battery electric battery voltage 3 of the vehicle 1 intended.

The described solution thus enables the charging of the battery 3 with a charging voltage corresponding to the battery voltage of, for example, 800 V at a corresponding charging station without the complex switching matrix via the direct connection of the first connecting branch Z1 and its closed charging contactors S1. Such loaders S1 are required in every variant for safety reasons. Likewise, the solution described allows the battery to be charged 3 with a charging voltage of, for example, 400 V, deviating from the battery voltage, at a corresponding charging station via the parallel second connecting branch Z 2, in which the DC-DC converter 7 is arranged. For this purpose, only two additional charging contactors S2 are required.

In one possible embodiment, the DC-DC converter 7 , as in 5 shown, in addition to the conversion of the battery 3 provided battery voltage to a deviating, in particular lower, voltage for electrical auxiliary consumers 10 of the vehicle 1 used. It is already known, such DC-DC converter 7 to use for such purposes, so that such a DC-DC converter 7 for the electrical power supply of auxiliary electrical consumers 10 , which anyway in the vehicle 1 is provided, in addition to charging the battery 3 can be used. As a result, no additional DC-DC converter is required and the additional cost of the solution described is limited to the two other charging contactors S2 in the parallel second connection branch Z2 with the DC-DC converter 7 , ie in the bypass to the first connection branch Z1.

In a further embodiment, not shown here is for charging the battery 3 used with the deviating from the battery voltage charging voltage a separate DC-DC converter, ie an additional DC-DC converter, in addition to for the electrical energy supply of the electrical auxiliary consumers 10 required DC-DC converter, if necessary. As a result, this for the electrical power supply of the electrical auxiliary consumers 10 required DC-DC converter are dimensioned smaller while charging for the battery 3 provided additional DC-DC converter, since he has to withstand higher currents, is more dimensioned.

The charging voltage of the respective external electrical energy source, ie the respective charging station, is expediently automatically determined and then the switches S1, S2, ie the charging contactors S1, S2, are switched accordingly to allow either direct charging via the first connecting branch Z1, if it is detected that the charging voltage corresponds to the battery voltage, or charging via the DC converter 7 to allow, if it is detected that the charging voltage is smaller or, for example, greater than the battery voltage and therefore by means of the DC-DC converter 7 Transformed to the battery voltage, ie transformed or transformed down, must be.

The charging voltage can be determined, for example, by measuring it and / or by detecting, for example, a corresponding marking of the charging station and / or by communicating with the charging station. For this purpose, the on-board DC charging device 8th expediently at least one corresponding detection device, which comprises, for example, a voltage measuring unit, a detection unit, for example, for detecting a corresponding mark on the charging station and / or a communication unit for communication with the charging station. Appropriately, then the switches S1, S2, ie the charging contactors S1, S2, the switching unit 9 switched accordingly to either the first connection branch Z1 without DC-DC converter 7 or the second connection branch Z2 with the DC-DC converter 7 close and thereby with the charging socket 5 and to connect via this with the vehicle external electrical energy source, such as the charging station.

Furthermore, it is expediently provided, the DC-DC converter 7 in the second connection branch Z2 for the transformation of the determined charging voltage to the battery voltage automatically set according to the determined charging voltage, if this deviates from the battery voltage and the second connection branch Z2 with the DC-DC converter 7 to charge the battery 3 is used. Ie. the DC-DC converter 7 in the second connection branch Z2 is expediently as a correspondingly adjustable DC-DC converter 7 educated.

LIST OF REFERENCE NUMBERS

1

vehicle

2

system

3

battery

3.1, 3.2

battery Pack

4

drive motor

5

charging socket

6

High-voltage onboard network

7

DC converter

8th

On-board DC charger

9

switching unit

10

In addition to consumer

A

output

e

entrance

S1

Switch, charging contactor

S2

another switch, another charging contactor

BS1 to BS7

internal battery switch, battery switch

Z1, Z2

connecting branch

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010041253 A1 [0003]

Claims (3)

On-board DC charging device ( 8th ) for a vehicle ( 1 ), characterized in that between a load-side inlet (E) and a battery-side output (A) two parallel electrical connection branches (Z1, Z2) are provided, wherein the one connection branch (Z1) a direct electrical connection between a charging socket ( 5 ) of the vehicle ( 1 ) and a battery ( 3 ) of the vehicle ( 1 ) and in the other connection branch (Z2) a DC-DC converter ( 7 ) and wherein a switching unit ( 9 ) is provided for closing the one connection branch (Z1) or the other connection branch (Z2). On-board DC charging device ( 8th ) according to claim 1, characterized in that the switching unit ( 9 ) comprises at least one switch (S1, S2), in particular contactor, in each of the two connection branches (Z1, Z2). On-board DC charging device ( 8th ) according to one of the preceding claims, characterized in that the DC-DC converter ( 7 ) for transforming, in particular for stepping up, an electrical charging voltage of a charging station to a deviating, in particular higher, battery electrical voltage of the battery ( 3 ) of the vehicle ( 1 ) is provided.

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