Multi-Voltage Storage System for an at Least Partly Electrically Driven Vehicle

Abstract

A multi-voltage storage system for an at least partly electrically driven vehicle includes a first storage module and a second storage module having an identical rated voltage for storing electrical energy, wherein on-board consumers are connected to the second storage module at least with priority during a charging process, a heating apparatus for heating the storage modules, a switch unit which is designed to connect the first storage module and the second storage module in series for a charging process and in parallel for driving the vehicle, and a control unit, which is firstly designed to control the switch unit before and/or during a charging process such that the parallel connection of the first storage module and the second storage module is eliminated, and which is secondly designed, after elimination of the parallel connection, to activate the heating apparatus before and/or during the charging process.

Claims

1.-5. (canceled)

6. A multi-voltage storage system for an at least partially electrically driven vehicle, the multi-voltage storage system comprising: a first storage module and a second storage module having an identical rated voltage for storing electrical energy, wherein on-board power system consumers are connected at least primarily to the second storage module during a charging process, a heating device for heating the storage modules, a switching unit that is configured to connect the first storage module and the second storage module in series for a charging process and to connect them in parallel for driving the vehicle, a control unit that is firstly configured to actuate the switching unit at least one of before or during a charging process such that a parallel circuit of the first storage module and of the second storage module is broken, and that is secondly configured to activate the heating device at least one of before or during the charging process after the parallel circuit has been broken, wherein an electrical energy demand for the heating device is drawn at least primarily from the first storage module.

7. The multi-voltage storage system according to claim 6, wherein the control unit is further configured to: determine in advance an expected energy demand, during the charging process, of the on-board power system consumers, wherein the expected energy demand is drawn at least primarily from the second storage module, and equalize the electrical energy demand for the heating device that is drawn at least primarily from the first storage module and the expected energy demand that is drawn at least primarily from the second storage module.

8. A method for operating a multi-voltage storage system for an at least partially electrically driven vehicle, the method comprising: providing a first storage module and a second storage module having an identical rated voltage for storing electrical energy, connecting on-board power system consumers at least primarily to the second storage module during a charging process, heating the storage modules by way of a heating device, providing a switching unit by way of which the first storage module and the second storage module are connected in series for a charging process and are connected in parallel for driving the vehicle, providing a control unit by way of which firstly the switching unit is actuated at least one of before or during a charging process such that a parallel circuit of the first storage module and of the second storage module is broken, and by way of which secondly the heating device is activated at least one before or during the charging process after the parallel circuit has been broken, and drawing an electrical energy demand for the heating device at least primarily from the first storage module.

9. The method according to claim 8, further comprising: determining in advance an expected electrical energy demand, during the charging process, of the on-board power system consumers, wherein the expected energy demand is drawn at least primarily from the second storage module, and equalizing the electrical energy demand for the heating device that is drawn at least primarily from the first storage module and the expected energy demand that is drawn at least primarily from the second storage module.

10. An electric vehicle comprising the multi-voltage storage system according to claim 6.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 shows the essential components of the system according to an embodiment of the invention in the case of decoupled storage modules.

[0029] FIG. 2 shows the essential components of the system according to an embodiment of the invention in the case of series-connected storage modules for fast charging.

[0030] FIG. 3 shows the essential components of the system according to an embodiment of the invention in the case of parallel-connected storage modules for driving the vehicle.

DETAILED DESCRIPTION OF THE DRAWINGS

[0031] FIGS. 1 to 3 schematically illustrate a vehicle having a two-voltage storage system and having an electric drive motor 5. Provision is made for a first storage module 1 and a second storage module 2 having an identical rated voltage (400 V) for storing electrical energy, wherein on-board power system consumers 6, such as in particular a heating and air-conditioning system, are connected at least primarily to the second storage module 2 during a charging process.

[0032] The storage modules 1 and 2 furthermore have a respective heating device 10 and 20 that are able to be actuated by an electronic control unit 3.

[0033] A switching unit 4 is designed to connect the first storage module 1 and the second storage module 2 in series for a charging process and to connect them in parallel for the drive of the vehicle.

[0034] The electronic control unit 3 is firstly designed to actuate the switching unit 4 before and/or during a charging process such that the parallel circuit of the first storage module 1 and of the second storage module 2 is broken.

[0035] The electronic control unit 3 is secondly designed to activate the heating devices 10 and 20 before and/or during the charging process after the parallel circuit has been broken, wherein the electrical energy demand for the heating devices 10 and 20 is drawn at least primarily from the first storage module 1.

[0036] The control unit 3 may in particular use an evaluation module 30 to determine in advance the expected electrical energy demand, during the charging process, of the on-board power system consumers 6, this being drawn at least primarily from the second storage module 2. To this end, the evaluation module 30 may for example take into consideration previously stored information about the duration of the next charging process and/or the current or expected switched-on state of on-board power system consumers 6.

[0037] The magnitude of the expected energy demand, determined in advance, that is drawn at least primarily from the second storage module 2 roughly defines the magnitude of the electrical energy demand to be expended for the heating devices 10 and 20, this being drawn at least primarily from the first storage module 1.

[0038] FIG. 1 shows a decoupled state of the storage modules 1 and 2 through the lack of a connection in the switching unit 4. The electrical energy demand for the heating devices 10 and 20 may be drawn from the first storage module 1 before a series connection or else during a series connection according to FIG. 2. FIG. 2 shows a series connection (here to give 800 V) for the fast charging of the storage modules 1 and 2.

[0039] During the fast charging, the energy already determined in advance for the on-board power system consumers is thus drawn from the non-heating storage module 2, this corresponding roughly to the energy that was being drawn before or at the same time from the heating storage module 1. At the end of the fast charging, the two storage modules 1 and 2 thereby have (roughly) the same state of charge (for example SOC=80%; SOC_H≈SOC_V) and may be connected back in parallel (here to give 400 V) immediately after the charging process for the drive 5 of the vehicle, as illustrated in FIG. 3 by the dashed lines in the switching unit 4.