High-voltage vehicle electrical system for an electrically driven vehicle

Abstract

The invention relates to a high-voltage vehicle electrical system (1) for an electrically driven vehicle, comprising at least one high-voltage battery (2, 2.1, 2.2), at least one electric drive (3, 4) and a plurality of auxiliary units (5 to 9), wherein at least one charging connection for DC charging of the high-voltage battery (2, 2.1, 2.2) and an on-board charger (11) for AC charging of the high-voltage battery (2, 2.1, 2.2) are arranged, wherein the high-voltage vehicle electrical system (1) has at least two separate subsystems (1.1, 1.2), each having its own high-voltage battery (2.1, 2.2), wherein the subsystems (1.1, 1.2) can be galvanically connected to one another by the on-board charger (11), which has a DC / DC converter (11.1), and energy can be transferred between the subsystems (1.1, 1.2) by means of the DC / DC converter (11.1), wherein the at least one electric drive (3, 4) and the plurality of auxiliary units (5 to 9) are permanently distributed between the two subsystems (1.1, 1.2).

Description

[0001] Mercedes-Benz Group AG

[0002] HV electrical system for an electrically powered vehicle

[0003] The invention relates to an HV electrical system for an electrically powered vehicle according to the preamble of claim 1.

[0004] DE 102021 003 831 A1 describes an electrical system for a vehicle, comprising a battery with two electrical battery potential contacts and a vehicle-side DC charging connection with two electrical charging potential contacts. A DC-DC converter is provided, wherein the first electrical battery potential contact is electrically coupled or can be coupled to a first electrical potential contact of an output side of the DC-DC converter, wherein the second electrical battery potential contact is electrically coupled or can be coupled to the second electrical charging potential contact, wherein the respective electrical charging potential contact is electrically coupled or can be coupled to a respective electrical potential contact of an input side of the DC-DC converter.wherein a second electrical potential contact of the output side of the DC-DC converter is electrically coupled or can be coupled to the first electrical potential contact of the input side of the DC-DC converter, wherein the electrical potential contacts of the input side of the DC-DC converter are each electrically coupled to an electrical connection contact of a first capacitor, and the electrical potential contacts of the output side of the DC-DC converter are each electrically coupled or can be coupled to an electrical connection contact of a second capacitor.

[0005] The invention is based on the object of specifying a novel HV electrical system for an electrically powered vehicle.

[0006] The object is achieved according to the invention by an HV electrical system for an electrically powered vehicle having the features of claim 1. Advantageous embodiments of the invention are the subject of the subclaims.

[0007] An HV electrical system for an electrically powered vehicle is proposed, comprising at least one HV battery, at least one electric drive, and a plurality of auxiliary units, wherein at least one charging connection for DC charging of the HV battery and an on-board charger for AC charging of the HV battery are arranged. According to the invention, the HV electrical system has at least two separate sub-networks, each having its own HV battery. The sub-networks can be galvanically connected to one another by the on-board charger, which has a DC / DC converter, and energy can be transferred between the sub-networks by the DC / DC converter. The at least one electric drive and the plurality of auxiliary units are permanently distributed between the two sub-networks.

[0008] The two or more separate sub-grids create a redundant HV electrical system and reduce the risk of the vehicle breaking down. Furthermore, the redundant HV electrical system enables autonomous driving. The EMC requirements apply to each sub-grid. The auxiliary units do not necessarily have to be designed to meet the high ripple requirements of the inverter. The separate sub-grids offer greater flexibility in the maximum permissible Y-capacity. If lower power is required from the drive, one of the HV batteries can be switched off. The voltage in the sub-grid with the switched off HV battery can be adjusted as needed by the on-board charger. This allows the drive inverter to operate more efficiently in the low-load range. The on-board charger can perform a pre-charging function. The on-board charger can also perform an active discharging function.

[0009] In one embodiment, the at least one drive or at least two drives are arranged in one of the sub-networks, wherein at least one of the auxiliary units, a plurality of the auxiliary units or all auxiliary units is / are arranged in another of the sub-networks.

[0010] In another embodiment, one of the drives is arranged in one of the sub-networks and the other drive is arranged in another of the sub-networks, with at least one of the auxiliary units, a majority of the auxiliary units, or all of the auxiliary units being arranged in the other of the sub-networks. In one embodiment, the sub-networks and their HV batteries have the same or different voltages and / or the HV batteries of the sub-networks have the same or different battery capacities.

[0011] In one embodiment, at least one of the HV batteries has a DC / DC converter for converting a high voltage to a low voltage to supply a redundant LV vehicle electrical system.

[0012] In one embodiment, a charging connection for DC charging is arranged in one of the sub-networks.

[0013] In another embodiment, a charging connection for DC charging is arranged in several or each of the sub-networks.

[0014] In one embodiment, one of the subnetworks serves only for basic supply and / or standby supply and / or redundancy.

[0015] In one embodiment, an HV heater and / or a DC / DC converter for converting a high voltage from the HV vehicle electrical system to a low voltage and / or an electric refrigerant compressor for an air conditioning system is / are provided as an auxiliary unit.

[0016] According to one aspect of the present invention, an electrically driven vehicle is proposed, comprising an HV electrical system as described above.

[0017] Embodiments of the invention are explained in more detail below with reference to drawings.

[0018] Showing:

[0019] Fig. 1 is a schematic view of an architecture of an HV electrical system of an electrically powered vehicle according to the prior art,

[0020] Fig. 2 is a schematic view of an architecture of an HV electrical system of an electrically powered vehicle according to one aspect of the present invention, Fig. 3 is a schematic view of an architecture of an HV electrical system of an electrically powered vehicle according to another aspect of the present invention, and

[0021] Fig. 4 is a schematic view of an architecture of an HV electrical system of an electrically powered vehicle according to another aspect of the present invention.

[0022] Corresponding parts are provided with the same reference numerals in all figures.

[0023] Figure 1 is a schematic view of an architecture of an HV electrical system 1 (high-voltage electrical system) of an electrically powered vehicle, for example a passenger car, a commercial vehicle or a bus, according to the prior art.

[0024] An HV battery 2 is provided, which serves as an electrical energy source and supplies energy to at least one HV component 3 to 7, including at least one electric drive 3, 4, in particular with a respective DC / AC converter (inverter), for example a front drive 3 and a rear drive 4, as well as at least one auxiliary unit 5, 6, 7, for example an HV heater 5, a DC / DC converter 6 for converting a high voltage from the HV on-board network 1 to a low voltage and / or an electric refrigerant compressor 7 with a DC / AC converter. The HV on-board network 1 ensures a power flow between the various HV components 3 to 7. The HV components 3 to 7 should operate as efficiently as possible across the entire voltage range of the HV battery 2.To charge the HV battery 2, there is the possibility of DC charging, in particular DC fast charging, from a DC charging station 8 via a DC box 9 or AC charging from an AC charging station 10 via an on-board charger 11 (OBL), which may have an AC / DC converter.

[0025] A failure of HV battery 2 causes the vehicle to stall. The architecture shown lacks redundancy for autonomous driving. DC charging imposes stricter EMC requirements on all active HV components 3 to 7. HV components 3 to 7 should be designed for high voltage ripple requirements caused by the inverter. Especially for an HV on-board network 1 with an operating voltage of 800 V, a maximum permissible Y-capacitance must be observed during DC charging and driving. Inverters operate less efficiently at lower power levels (due to the on-board network voltage). The on-board charger 11 is only required for AC charging. While driving, it merely acts as ballast.

[0026] Figure 2 is a schematic view of an architecture of an HV electrical system 1 (high-voltage electrical system) of an electrically powered vehicle, for example a passenger car, a commercial vehicle or a bus, according to one aspect of the present invention.

[0027] In this architecture, the HV battery 2 has two separate cell blocks 2.1, 2.2, or two HV batteries 2.1, 2.2 are provided. The cell blocks 2.1, 2.2 or HV batteries 2.1, 2.2 can have different power outputs depending on requirements.

[0028] The cell blocks 2.1, 2.2 serve as electrical energy sources and supply several HV components 3 to 7, including at least one electric drive 3, 4, in particular with a respective DC / AC converter, for example a front drive 3 and a rear drive 4, as well as at least one auxiliary unit 5, 6, 7, for example an HV heater 5, a DC / DC converter 6 for converting a high voltage from the HV on-board network 1 to a low voltage and / or an electric refrigerant compressor 7 with a DC / AC converter, with energy.

[0029] In order to charge the cell blocks 2.1, 2.2, there is the possibility of DC charging, in particular DC fast charging, from a DC charging station 8 via a DC box 9 or AC charging from an AC charging station 10 via an on-board charger 11 (OBL), which can have an AC / DC converter or a DC / DC converter 11.1 and / or an upstream power factor correction filter 11.2.

[0030] For example, cell block 2.1 can be arranged in a sub-network 1.1 of the HV on-board network 1 to supply the drives 3, 4. A second cell block 2.2 can be arranged in a further sub-network 1.2 of the HV on-board network 1 and serve as an energy source for several auxiliary units 5, 6, 7, 12. The on-board charger 11 galvanically separates the two sub-networks 1.1, 1.2 and can, if necessary, galvanically couple them and transport energy back and forth between the two sub-networks 1.1, 1.2. The voltage ranges of the two sub-networks 1.1, 1.2 can be different. Optionally, at least one of the cell blocks 2.1, 2.2 can have a DC / DC converter 6', 6" for converting a high voltage to a low voltage to supply a redundant LV on-board network 13, 13' (low-voltage on-board network). For each of the sub-networks 1.1, 1.2, the option of DC charging, in particular DC fast charging, from a DC charging station 8 via a DC box 9, 9' can be provided separately.

[0031] The two separate sub-grids 1.1, 1.2 create a redundant HV on-board network 1 and reduce the risk of the vehicle breaking down. Furthermore, the redundant HV on-board network 1 enables autonomous driving. The EMC requirements apply to the respective sub-grids 1.1, 1.2. The auxiliary units 5, 6, 7 do not necessarily have to be designed for the high ripple requirements of the inverter. The separate sub-grids 1.1, 1.2 offer more freedom in the maximum permissible Y-capacity. If lower power is required from the drive 3, 4, the cell block 2.1 can be switched off. The voltage in sub-grid 1.1 can be adjusted as needed by the on-board charger 11. This allows the inverter of the drive 3, 4 to operate more efficiently in the low-load range. The on-board charger 11 can assume a pre-charging function. The on-board charger 11 can also perform an active discharge function.

[0032] Two DC / DC converters 6', 6" for converting a high voltage to a low voltage to supply a redundant LV on-board network 13, 13' in the separate sub-networks 1.1, 1.2 can provide redundancy and LV batteries could be omitted.

[0033] For example, one of the sub-networks 1.1, 1.2 could be designed for 500 V and others of the sub-networks 1.1, 1.2 could be designed for 800 V and thus charging at both a DC charging station 8 with a voltage of 800 V and a DC charging station 8 with a voltage of 500 V charging column.

[0034] Figure 3 is a schematic view of an architecture of an HV electrical system 1 (high-voltage electrical system) of an electrically powered vehicle, for example a passenger car, a commercial vehicle, or a bus, according to a further aspect of the present invention. The embodiment shown in Figure 3 largely corresponds to the embodiment according to Figure 2. In contrast, the two drives 3, 4 are distributed between the two sub-networks 1.1, 1.2. This means that one of the drives 3 is arranged in sub-network 1.1 and the other drive 4 is arranged in the other sub-network 1.2. This makes it possible to continue driving with full drive power in the event of a fault. In the embodiment shown in Figure 2, however, the drive power is limited to the power of the on-board charger 11 if the cell block 2.1 fails.

[0035] Figure 4 is a schematic view of an architecture of an HV electrical system 1 (high-voltage electrical system) of an electrically powered vehicle, for example a passenger car, a commercial vehicle or a bus, according to a further aspect of the present invention, wherein the architecture is highly integrated.

[0036] According to the present invention, the central HV on-board electrical system 1 previously provided in the vehicle is divided into two or more separate sub-networks 1.1, 1.2, which are connected via a central converter, in particular a converter of an on-board charger 11. The sub-networks 1.1, 1.2 are partially autonomous and each have clearly assigned components as well as their own cell block 2.1, 2.2 or their own HV battery 2.1, 2.2. These HV batteries 2.1, 2.2 or cell blocks 2.1, 2.2 do not necessarily have to be designed the same. The battery capacity and also the battery type and / or the battery voltage can differ here, since the coupling of the two sub-networks 1.1, 1.2 only takes place via the converter, which can compensate here. The architectures can differ and also the assignment of the HV components 3 to 7, so that all drives 3, 4 can be arranged in one subnetwork 1.1, 1.2 or distributed in both subnetworks 1.1, 1.2.Furthermore, it can also be provided that one of the subnetworks 1.1, 1.2 represents only the basic supply and / or standby supply and / or redundancy or more.

[0037] AC charging can occur for both sub-grids 1.1, 1.2 simultaneously, as this feeds directly into the converter (on-board charger 11) at the connection between both sub-grids 1.1, 1.2. DC charging primarily takes place in sub-grid 1.1 with drives 3, 4 or the larger drive 3, 4 and thus with the larger HV battery 2.1, 2.2. The other HV battery 2.1, 2.2 of the other sub-grid 1.1, 1.2 can then be charged via the converter (on-board charger 11) during charging or, depending on the state of charge (SOC) of the larger HV battery 2.1, 2.2 and its use, can also be charged solely from the larger HV battery 2.1, 2.2 as a "balancing" during charging or at any time. Alternatively, a separate DC box 9, 9' for DC charging in the second sub-network 1.2 is possible, so that the respective sub-networks 1.1, 1.2 can be charged more quickly, either individually or collectively via the converter (on-board charger 11), even in parallel with two charging connections. The smaller of the HV batteries 2.1, 2.2 can also be small in design, as long as it only concerns one subsystem and / or redundancies and / or an emergency system and / or a heating system (during charging), etc.

[0038] More than two sub-networks 1.1, 1.2, each with its own HV battery 2.1, 2.2, can be provided, for example three or more sub-networks 1.1, 1.2, each with its own HV battery 2.1, 2.2.

[0039] List of reference symbols

[0040] 1 HV electrical system

[0041] 1.1 , 1.2 Subnet

[0042] 2 HV batteries

[0043] 2.1 , 2.2 HV battery, cell block

[0044] 3 HV component, drive, front drive

[0045] 4 HV component, drive, rear drive

[0046] 5 HV component, auxiliary unit, HV heater

[0047] 6 HV component, auxiliary unit, DC / DC converter

[0048] 6', 6" HV component, DC / DC converter

[0049] 7 HV component, auxiliary unit, electric refrigerant compressor

[0050] 8 DC charging station

[0051] 9.9' DC Box

[0052] 10 AC charging stations

[0053] 11 On-board chargers

[0054] 11.1 DC / DC converter

[0055] 11.2 Power correction filter

[0056] 12 Auxiliary unit

Claims

Mercedes-Benz Group AG Patent claims 1. HV on-board network (1) for an electrically powered vehicle, comprising at least one HV battery (2, 2.1, 2.2), at least one electric drive (3, 4) and a plurality of electrical auxiliary units (5 to 9), wherein at least one charging connection for DC charging of the HV battery (2, 2.1, 2.2) and an on-board charger (11) for AC charging of the HV battery (2, 2.1, 2.2) are arranged, characterized in that the HV on-board network (1) has at least two separate sub-networks (1.1, 1.2), each having its own HV battery (2.1, 2.2), wherein the sub-networks (1.1, 1.2) can be galvanically connected to one another by the on-board charger (11), which has a DC / DC converter (11.1), and by the DC / DC converter (11.1) energy can be transferred between the sub-networks (1.1, 1.2), wherein the at least one electric drive (3, 4) and the plurality of auxiliary units (5 to 9) are permanently distributed between the two sub-networks (1.1, 1.2).

2. HV on-board network (1) according to claim 1, characterized in that the at least one drive (3, 4) or at least two drives (3, 4) is / are arranged in one of the sub-networks (1.1), wherein at least one of the auxiliary units (5, 6, 7, 12), a plurality of the auxiliary units (5, 6, 7, 12) or all of the auxiliary units (5, 6, 7, 12) are arranged in another of the sub-networks (1.2).

3. HV on-board network (1) according to claim 1, characterized in that one of the drives (3) is arranged in one of the sub-networks (1.1) and the other drive (4) is arranged in another of the sub-networks (1.2), wherein at least one of the auxiliary units (5, 6, 7, 12), a plurality of the auxiliary units (5, 6, 7, 12) or all of the auxiliary units (5, 6, 7, 12) are arranged in the other of the sub-networks (1.2).

4. HV on-board network (1) according to one of the preceding claims, characterized in that the sub-networks (1.1, 1.2) and their HV Batteries (2.1, 2.2) have the same or different voltages and / or that the HV batteries (2.1, 2.2) have the same or different battery capacities.

5. HV on-board network (1) according to one of the preceding claims, characterized in that at least one of the HV batteries (2.1, 2.2) has a DC / DC converter (6', 6") for converting a high voltage to a low voltage for supplying a redundant LV on-board network (13, 13').

6. HV vehicle electrical system (1) according to one of the preceding claims, characterized in that a charging connection for DC voltage charging is arranged in one of the sub-networks (1.1, 1.2).

7. HV vehicle electrical system (1) according to one of claims 1 to 5, characterized in that in several or each of the sub-networks (1.1, 1.2) a charging connection for DC voltage charging is arranged.

8. HV on-board network (1) according to one of the preceding claims, characterized in that one of the sub-networks (1.1, 1.2) serves only for basic supply and / or standby supply and / or redundancy.

9. HV on-board network (1) according to one of the preceding claims, characterized in that an HV heater (5) and / or a DC / DC converter (6) for converting a high voltage from the HV on-board network (1) to a low voltage and / or an electric refrigerant compressor (7) for an air conditioning system is provided as an auxiliary unit (5, 6, 7).

10. Electrically powered vehicle comprising an HV electrical system (1) according to one of the preceding claims.

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