Energy supply device of an electrically operable vehicle and method for operating an energy supply device

Abstract

The invention relates to an energy supply device (100) of an electrically operable vehicle, comprising a high-voltage on-board electrical system (10) with a first input pole (84) and a second input pole (86), and at least one low-voltage network (30) with safety-critical consumers, which has a primary low-voltage supply (32) and a redundant low-voltage supply (34). The high-voltage battery (20) is designed as a series connection of a first group (22) of battery cells (26) with a second group (24) of battery cells (26). The second group (24) of battery cells (26) forms the redundant low-voltage supply (34). The low-voltage network (30) can be or is electrically coupled to a first terminal (76) via a fourth switch (36) and to a second terminal (78) of the second group (24) of battery cells (26) via a fifth switch (38).The second input pole (84) of the high-voltage vehicle electrical system (10) can be or is electrically coupled to a second terminal (82) of the first group (22) of battery cells (26) via an additional supply line (44) in which a sixth switch (46) is arranged.

Description

[0001] The invention relates to an energy supply device for an electrically operated vehicle and a method for operating an energy supply device for an electrically operated vehicle.

[0002] High-voltage / low-voltage power supply systems for safety-critical components in electric vehicles, such as steer-by-wire systems, brake-by-wire systems, or components for autonomous driving, typically include an additional high-voltage or low-voltage battery within the vehicle or utilize highly reliable power supply systems with at least two DC / DC converters. A disadvantage of this approach is the requirement for two DC / DC converters, which must operate with a high degree of independence from each other. Furthermore, an additional low-voltage battery is required in the vehicle alongside the high-voltage battery. Faults in the high-voltage electrical system that could lead to impermissibly high or low high-voltage battery voltages must be prevented with a very high degree of reliability.

[0003] DE 10 2019 000 352 A1 discloses a power supply device comprising a housing and a first power source providing a first voltage, a DC-DC converter in which the first voltage can be transformed into a second voltage, and a first voltage output on the housing at which the second voltage can be provided, wherein a second power source is integrated into the housing, providing the second voltage independently of the DC-DC converter. The power supply unit is, for example, equipped with an undervoltage protection device that can be activated when the voltage falls below a predefined threshold for the second voltage.

[0004] German patent DE 10 2021 204 999 A1 describes an energy supply system for an electric or hybrid vehicle, comprising a low-voltage network, a high-voltage network, and at least one high-voltage battery. The high-voltage battery has a series connection of a plurality of battery cells, to which further battery cells can optionally be connected in parallel. The low-voltage network also has a redundant power supply, with at least one power supply of the low-voltage network being formed by a series connection of a group of battery cells from the high-voltage battery. The taps of the series connection of the group of battery cells are connected to the low-voltage network via a circuit arrangement with switching elements.

[0005] DE 10 2022 003 783 A1 discloses a device for pre-charging a high-voltage electrical system of an electric vehicle, wherein a high-voltage energy storage device is electrically coupled to a secondary DC / DC converter, at least for charging purposes. The high-voltage energy storage device is electrically coupled to the high-voltage electrical system and a primary DC / DC converter via at least one high-voltage switch, as required. The primary DC / DC converter is electrically coupled to a primary low-voltage electrical system. The secondary DC / DC converter is electrically coupled to a secondary low-voltage electrical system and, as required, via at least one low-voltage switch, to an electrical connection between the primary DC / DC converter and the low-voltage electrical system. Furthermore, a method for pre-charging a high-voltage electrical system of an electric vehicle is disclosed.

[0006] A redundant low-voltage power supply system with a high-voltage battery pack is known from US 2023 / 0 253 805 A1.

[0007] The generic document DE 10 2012 220 549 A1 concerns a vehicle electrical system with the possibility of supplying a low-voltage network either via a DC / DC converter or via a part of the high-voltage battery.

[0008] One object of the invention is to create an energy supply device for an electrically operated vehicle which ensures the safe operation of safety-critical consumers.

[0009] Another task is to specify a method for operating such an energy supply device for an electrically powered vehicle.

[0010] The aforementioned tasks are solved using the characteristics of independent claims.

[0011] Favorable embodiments and advantages of the invention will become apparent from the further claims, the description and the drawing.

[0012] According to one aspect of the invention, a power supply device for an electrically operated vehicle is proposed, comprising a high-voltage electrical system with a first input terminal and a second input terminal, wherein the first input terminal is electrically connectable or coupled to a first terminal of a high-voltage battery via a first switch, and the second input terminal is electrically connectable or coupled to a second terminal of the high-voltage battery via a second switch, and at least one low-voltage network with safety-critical loads, which has a primary low-voltage supply and a redundant low-voltage supply. The high-voltage battery is configured as a series connection of a first group of battery cells with a second group of battery cells. The first group forms the first terminal of the high-voltage battery via a first terminal and is electrically connectable or coupled to a first terminal of the second group via a third switch.The second group of cells, with its second terminal, forms the second pole of the high-voltage battery. This second group of battery cells provides a redundant low-voltage supply, with the low-voltage network electrically connected to the first terminal of the second group of battery cells via a fourth switch and to the second terminal via a fifth switch. The second input terminal of the high-voltage electrical system is electrically connected to the second terminal of the first group of battery cells via an additional supply line containing a sixth switch.

[0013] Advantageously, the proposed power supply system features a redundant low-voltage supply for safety-critical low-voltage loads such as a steer-by-wire or break-by-wire system. This ensures that a redundant low-voltage supply channel is available in the event of a primary low-voltage supply failure.

[0014] The first and second switches describe the main contactors for isolating the high-voltage electrical system from the high-voltage battery.

[0015] The third switch, which can be designed as a contactor, for example, is arranged in the high-voltage battery in such a way that by opening the third switch, the second group of battery cells can serve as a low-voltage storage unit, for example with a voltage of 48V, which can feed the low-voltage network.

[0016] The fourth and fifth switches, as low-voltage switches, are only activated in the event of a fault to continue supplying the safety-critical low-voltage consumers.

[0017] This eliminates the need for an additional low-voltage battery in the vehicle. Instead, redundant energy storage is generated by switchable groups of cells from the high-voltage battery. Another advantage is that only one DC / DC converter is required.

[0018] Furthermore, the power supply unit features an additional supply line between the high-voltage battery and the second input terminal of the high-voltage electrical system, for example, the negative terminal, which can be activated via the sixth switch. Under normal operating conditions, the sixth switch is permanently open. If the redundant low-voltage supply is activated in the event of a fault, closing the sixth switch allows the high-voltage electrical system to continue to be supplied with power at a slightly reduced level, thus maintaining vehicle propulsion.

[0019] Advantageously, the vehicle can continue to supply the high-voltage electrical system and thus provide propulsion, even when supplied by the redundant low-voltage supply.

[0020] According to an advantageous design of the power supply unit, a DC / DC converter can be electrically coupled to the high-voltage vehicle electrical system, forming the primary low-voltage supply for the low-voltage network. In this way, the low-voltage consumers in the vehicle can be supplied cost-effectively during normal operation.

[0021] According to an advantageous embodiment of the power supply unit, the DC / DC converter can be electrically coupled to the high-voltage electrical system in parallel with the first and second switches and can be switched via a seventh switch. For increased reliability, the DC / DC converter can be connected in parallel with the first and second switches and disconnected by the seventh switch. This allows, in the event of a fault, both the high-voltage electrical system to be disconnected from the high-voltage battery and the DC / DC converter itself to be switched off separately.

[0022] According to an advantageous design of the energy supply system, the low-voltage network can have a buffer capacity. In the event of a fault, this buffer capacity can bridge the operation of safety-critical loads in the low-voltage network for a certain period of time until the supply is ensured by the second group of battery cells of the high-voltage battery.

[0023] According to an advantageous embodiment of the power supply device, the third switch can be designed as a switching element that can be disconnected under load. In particular, the third switch can be designed as a pyrotechnic disconnecting element. The third switch can be designed as a switching element that can be disconnected under load, with an air gap when open, for example, a contactor of this type. Advantageously, the third switch can be designed as a pyrotechnic disconnecting element, which additionally serves as a main fuse for the high-voltage battery against overcurrent / short circuit to the high-voltage electrical system.

[0024] According to an advantageous embodiment of the power supply device, the second, third, and seventh switches can be controlled via a first common release contact, the fourth and fifth switches via a second common release contact, and the sixth switch via the second release contact or a third release contact. Advantageously, in the event of a fault, the second, third, and seventh switches can be simultaneously switched to disconnect the high-voltage battery from the high-voltage electrical system and to disconnect the DC / DC converter from the high-voltage battery. The second group of battery cells of the high-voltage battery can also be connected simultaneously via the fifth and sixth switches. The supply to the high-voltage electrical system from the first group of battery cells of the high-voltage battery can then also be activated.

[0025] According to a further aspect of the invention, a method for operating an energy supply device of an electrically operated vehicle is proposed, wherein, in the event of a fault in a primary low-voltage supply of a low-voltage network with safety-critical consumers, a switchover to a redundant low-voltage supply of the low-voltage network and an electrical supply of a high-voltage on-board network with reduced voltage from a high-voltage battery is carried out.

[0026] The proposed method advantageously ensures that in the event of a fault in the primary low-voltage supply of the safety-critical consumers, for example in the event of a failure of the DC / DC converter, a switch to the redundant low-voltage supply can be ensured.

[0027] Furthermore, it can be advantageously ensured that the high-voltage electrical system continues to be supplied with slightly reduced power, thus maintaining the vehicle's propulsion.

[0028] According to an advantageous embodiment of the method, at least a second and third switch can be opened and a fourth and fifth switch can be closed, and the low-voltage network can be supplied with an electrical voltage applied to the terminals of a second group of battery cells of the high-voltage battery. A sixth switch can be closed, and the high-voltage electrical system can be supplied with an electrical voltage applied to the terminals of a first group of battery cells of the high-voltage battery. In particular, the at least second and third switches can be switched via a first common release contact, the fourth and fifth switches via a second common release contact, and the sixth switch via the second release contact or a third release contact.

[0029] A control unit that detects a fault triggers the switchover to the redundant low-voltage supply. To do this, the control unit opens the second and third switches, which are implemented as switches / contactors or pyrotechnic isolating elements. This creates a low-voltage storage unit, for example with a voltage of 48V, using the second group of battery cells from the high-voltage battery, isolated from the high-voltage potential.

[0030] A buffer capacity in the low-voltage network can continue to supply the safety-critical low-voltage consumers during this time.

[0031] After the second and third switches are fully opened, the fourth and fifth switches are closed. The supply to the safety-critical low-voltage consumers is ensured by the low-voltage cell block of the high-voltage battery thus generated.

[0032] By closing the sixth switch, the high-voltage electrical system can be powered from an electrical voltage applied to the terminals of the first group of battery cells of the high-voltage battery, thus maintaining the vehicle's propulsion.

[0033] According to an advantageous embodiment of the method, the low-voltage network can be electrically supplied via a buffer capacity between the opening of at least the second and third switches and the closing of the fourth and fifth switches. In this way, the operation of safety-critical loads can be bridged for a certain period of time until the supply via the second group of battery cells of the high-voltage battery is ensured.

[0034] Alternatively or additionally, the fourth, fifth, and sixth switches can be closed instantly when at least the second and third switches are opened. In the case of a redundant low-voltage power supply with double and reinforced insulation and touch protection, the buffer capacity can be omitted, and the fourth and fifth switches can be closed simultaneously when the second and third switches are opened.

[0035] According to an advantageous embodiment of the method, the seventh switch can be opened together with the second and third switches. This allows a potentially faulty DC / DC converter to be reliably disconnected from the high-voltage supply.

[0036] Further advantages will become apparent from the following description of the drawing. The drawing illustrates an embodiment of the invention. The drawing, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently consider the features individually and combine them into meaningful further combinations.

[0037] This shows: Fig. 1 a system overview of an energy supply device of an electrically operated vehicle according to an embodiment of the invention.

[0038] The figure merely shows an example and is not to be understood as limiting.

[0039] Fig. Figure 1 shows a system overview of an energy supply unit 100 of an electrically operated vehicle according to an embodiment of the invention.

[0040] The power supply unit 100 comprises a high-voltage electrical system 10 with a first input terminal 84 and a second input terminal 86. The first input terminal 84 can be electrically connected or coupled to a first terminal 72 of a high-voltage battery 20 via a first switch 12, and the second input terminal 86 can be connected to a second terminal 74 of the high-voltage battery 20 via a second switch 14.

[0041] Furthermore, the energy supply facility 100 includes a low-voltage network 30 with safety-critical consumers, which has a primary low-voltage supply 32 and a redundant low-voltage supply 34, as well as another low-voltage network 50 with non-safety-critical consumers.

[0042] A DC / DC converter 40 is electrically coupled to the high-voltage on-board network 10, which forms the primary low-voltage supply 32 for the two low-voltage networks 30, 50.

[0043] The DC / DC converter 40 is electrically coupled in parallel to the first and second switches 12, 14 with the high-voltage on-board network 10 and can be switched off via a seventh switch 18.

[0044] The high-voltage battery 20 is designed as a series connection of a first group 22 of battery cells 26 with a second group 24 of battery cells 26.

[0045] The first group 22, with a first terminal 80, forms the first pole 72 of the high-voltage battery 20 and is electrically connectable or coupled via a second terminal 82 to a first terminal 76 of the second group 24 via a third switch 16. The third switch 16 is designed as a switching element that can be disconnected under load. In particular, the third switch 16 can advantageously be designed as a pyrotechnic disconnecting element.

[0046] The second group 24 forms the second pole 74 of the high-voltage battery 20 with a second connection 78.

[0047] The second group 24 of battery cells 26 forms the redundant low-voltage supply 34.

[0048] The low-voltage network 30 can be electrically coupled or connected via a fourth switch 36 to the first connection 76 and via a fifth switch 38 to the second connection 78 of the second group 24 of battery cells 26.

[0049] The second input pole 84 of the high-voltage on-board network 10 can be electrically coupled or connected to the second terminal 82 of the first group 22 of battery cells 26 via an additional supply line 44 in which a sixth switch 46 is arranged.

[0050] The low-voltage network 30 further has a buffer capacity 42 in its primary low-voltage supply 32, with which the operation of the safety-critical consumers can be bridged for a certain period of time.

[0051] The second, third, and seventh switches 14, 16, 18 can be switched via a first common release contact 60, and the fourth and fifth switches 36, 38 can be switched via a second common release contact 62. The sixth switch 46 can be switched via the second release contact 62 or a third release contact 64. The first switch 12 can be switched via a further fourth release contact 66.

[0052] In normal operation of the power supply unit 100, the third switch 16 is closed, so the high-voltage battery 20 is in normal operation. The first and second switches 12, 14 are closed, so the high-voltage electrical system 10 is in normal operation. The seventh switch 18 is closed, so the DC / DC converter 40 is in normal operation. The fifth and sixth switches 36, 38 are open, so the low-voltage network 30, including the safety-critical loads, is supplied via the primary low-voltage supply 32 through the DC / DC converter 40.

[0053] In the event of a fault in the primary low-voltage supply 32 of the low-voltage network 30 with the safety-critical consumers, a switchover to the redundant low-voltage supply 34 of the low-voltage network 30 is carried out and the electrical supply of the high-voltage on-board network 10 is taken up with reduced voltage from the high-voltage battery 20.

[0054] A control unit (not shown) triggers the switchover to the redundant low-voltage supply. For this purpose, the control unit opens the second, third, and preferably also the seventh switch 14, 16, 18, which are designed as switches / contactors or PTEs (pyrotechnic isolating elements). This creates a low-voltage storage unit (e.g., 48V) isolated from the high-voltage potential in the form of the second group 24 of battery cells 26 of the high-voltage battery 20.

[0055] Meanwhile, the buffer capacity 42 in the low-voltage on-board network 30 continues to supply the safety-critical low-voltage consumers.

[0056] After switches 14, 16, and 18 are fully opened, the fourth and fifth switches 36 and 38 are closed. The low-voltage network 30 is thus supplied with electricity from the voltage present at terminals 76 and 78 of the second group 24 of battery cells 26 of the high-voltage battery 20.

[0057] The sixth switch 46 is closed, and the high-voltage electrical system 10 continues to operate using the electrical voltage applied to terminals 80 and 82 of the first group 22 of battery cells 26 of the high-voltage battery 20. The vehicle's driving function is thus maintained.

[0058] Conveniently, the fourth, fifth and sixth switches 36, 38, 46 can be closed instantly when at least the second and third switches 14, 16 are opened.

[0059] Alternatively, in the case of a redundant low-voltage power supply with double and reinforced insulation and touch protection, the buffer capacity 42 can be omitted and the fourth and fifth switches 36, 38 can be closed simultaneously when the second, third and fourth switches 14, 16, 18 are opened. Reference symbol list 10 High-voltage electrical system 12 first switch 14 second switch 16 third switch 18 seventh switch 20 high-voltage batteries 22 first group of battery cells 24 second group of battery cells 26 battery cells 30 Low-voltage network 32 primary low-voltage supply 34 redundant low-voltage power supplies 36 fourth switch 38 fifth switch 40 DC / DC converters 42 Buffer capacity 44 additional supply lines 46 sixth switch 50 Low-voltage network 60 first trigger contact 62 second trigger contact 64 third trigger contact 66 fourth trigger contact 72 first pole 74 second pole 76 Connection second group 78 Connection second group 80 connection first group 82 Connection first group 84 Input pole 86 Input pole 100 Energy supply unit

Claims

[1] Energy supply unit (100) of an electrically powered vehicle, comprising a high-voltage electrical system (10) with a first input terminal (84) and a second input terminal (86), wherein the first input terminal (84) can be electrically coupled or connected to a first terminal (72) of a high-voltage battery (20) via a first switch (12) and the second input terminal (86) can be electrically coupled or connected to a second terminal (74) of the high-voltage battery (20) via a second switch (14), at least one low-voltage network (30) with safety-critical consumers, which has a primary low-voltage supply (32) and a redundant low-voltage supply (34), wherein the high-voltage battery (20) is configured as a series connection of a first group (22) of battery cells (26) with a second group (24) of battery cells (26), wherein the first group (22) with a first terminal (80) forms the first pole (72) of the high-voltage battery (20) and is electrically connectable or coupled via a third switch (16) to a first terminal (76) of the second group (24) via a second terminal (82), wherein the second group (24) with a second connection (78) forms the second pole (74) of the high-voltage battery (20), wherein the second group (24) of battery cells (26) forms the redundant low-voltage supply (34), wherein the low-voltage network (30) can be electrically coupled or connected via a fourth switch (36) to the first terminal (76) and via a fifth switch (38) to the second terminal (78) of the second group (24) of battery cells (26), wherein the second input pole (86) of the high-voltage on-board network (10) can be electrically coupled or connected to the second terminal (82) of the first group (22) of battery cells (26) via an additional supply line (44) in which a sixth switch (46) is arranged. [2] Power supply device according to claim 1, wherein a DC / DC converter (40) is electrically coupled to the high-voltage on-board network (10), which forms the primary low-voltage supply (32) for the low-voltage network (30). [3] Power supply device according to claim 2, wherein the DC / DC converter (40) is electrically coupled in parallel to the first and second switches (12, 14) to the high-voltage on-board network (10) and can be switched via a seventh switch (18). [4] Energy supply device according to one of the preceding claims, wherein the low-voltage network (30) has a buffer capacity (42). [5] Power supply device according to one of the preceding claims, wherein the third switch (16) is designed as a switching element that can be disconnected under load, [6] Power supply device according to one of claims 3 to 5, wherein the second, third and seventh switches (14, 16, 18) are switchable via a first common release contact (60) and the fourth and fifth switches (36, 38) are switchable via a second common release contact (62) and the sixth switch (46) is switchable via the second release contact (62) or a third release contact (64). [7] Method for operating an energy supply device (100) of an electrically operated vehicle according to one of the preceding claims, wherein, in the event of a fault in a primary low-voltage supply (32) of a low-voltage network (30) with safety-critical consumers, a switchover to a redundant low-voltage supply (34) of the low-voltage network (30) and an electrical supply of a high-voltage on-board network (10) with reduced voltage from a high-voltage battery (20) is carried out. [8] Method according to claim 7, wherein at least a second and third switch (14, 16) are opened and a fourth and fifth switch (36, 38) are closed, and the low-voltage network (30) is supplied from an electrical voltage applied to terminals (76, 78) of a second group (24) of battery cells (26) of the high-voltage battery (20), and wherein a sixth switch (46) is closed, and the high-voltage on-board network (10) is supplied from an electrical voltage applied to terminals (80, 82) of a first group (22) of battery cells (26) of the high-voltage battery (20). [9] Method according to claim 8, wherein between opening the at least second and third switches (14, 16) and closing the fourth and fifth switches (36, 38) the low-voltage network (30) is electrically supplied via a buffer capacity (42), and / or wherein the fourth, fifth and sixth switches (36, 38, 46) are closed instantaneously when the at least second and third switches (14, 16) are opened. [10] Method according to claim 8 or 9, wherein the seventh switch (18) is opened together with the second and third switches (14, 16).

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