Electrical system and method for operating an electrical system

• US 10,071,646 B2
• Filed: 01/23/2015
• Issued: 09/11/2018
• Est. Priority Date: 01/27/2014
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH, Samsung SDI Company Limited
• Original Assignee: Robert Bosch GmbH, Samsung SDI Company Limited
• Inventors: Fink, Holger
• Primary Examiner(s): Sample, Jonathan L
• Application Number:
  US15/114,550
• Publication Number:
  US 20160347197A1
• Time in Patent Office: 1,327 Days
• Field of Search: 701 22, 701 36
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2260/20 Drive modes; Transition between modes
• CPC Class Codes: B60L 2260/22 Standstill, e.g. zero speed
• CPC Class Codes: B60L 2260/24 Coasting mode
• CPC Class Codes: B60L 2260/26 Transition between different drive modes
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: B60L 58/19 Switching between serial connection and parallel connection of battery modules
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: B60R 16/033 characterised by the use of electrical cells or batteries for propulsion puposes B60K1/04; supplying batteries to, or removing batteries from, vehicles B60S5/06; testing of charge state G01R31/36
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: H02J 2310/46 for ICE-powered road vehicles
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/0024 Parallel/serial switching of connection of batteries to charge or load circuit
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y10S 903/907 Electricity storage, e.g. battery, capacitor

Abstract

The disclosure relates to an electrical system for a vehicle, comprising a low-voltage sub-network for at least one low-voltage load and comprising a high-voltage sub-network for at least one high-voltage load and an electric generator. The high-voltage sub-network has a battery which is designed to generate a high-voltage and output same to the high-voltage sub-network and which has at least two battery units with individual voltage taps. The high-voltage sub-network is connected to the low-voltage sub-network via a coupling unit which is designed to draw energy from the high-voltage sub-network and supply said energy to the low-voltage sub-network. The coupling unit is designed to selectively connect the battery units to the low-voltage sub-network. The disclosure further relates to a method for operating an electrical system, to a motor vehicle, and to a battery management system and a computer program which are designed to carry out the method.

Claims

1. An onboard electrical system for a motor vehicle, having

a first subsystem having at least one first load configured to operate with a first voltage;

a second subsystem having at least one second load configured to operate with a second voltage, the second voltage being higher than the first voltage, the second subsystem having a battery configured to produce the second voltage and to output the second voltage to the second subsystem, the battery having at least two battery units having individual voltage taps;

an electrical generator;

a coupling unit configured to connect the second subsystem to the first subsystem, the coupling unit being configured to draw power from the second subsystem and to supply the power to the first subsystem, the individual voltage taps of the at least two battery units being routed to the coupling unit, the coupling unit being configured to selectively connect individual ones of the at least two battery units to the first subsystem; and

a controller operably connected to the coupling unit, the controller being configured to (i) ascertain a state of charge of each of the at least two battery units and (ii) operate the coupling unit to connect a battery unit of the at least two battery units that has a highest state of charge to the first subsystem.

2. The onboard electrical system as claimed in claim 1, wherein the at least two battery units are each configured to provide the first voltage.

3. The onboard electrical system as claimed in claim 1, wherein the coupling unit includes switches configured to, in an on state, allow current to flow in only one direction.

4. The onboard electrical system as claimed in claim 1, wherein the first subsystem includes at least one energy store configured to produce the first voltage and to output the first voltage to the first subsystem.

5. The onboard electrical system as claimed in claim 1, wherein the first subsystem includes a starter.

6. A method for operating an onboard electrical system for a motor vehicle, the onboard electrical system including (i) a first subsystem having at least one first load configured to operate with a first voltage, (ii) a second subsystem having at least one second load configured to operate with a second voltage, the second voltage being higher than the first voltage, the second subsystem having a battery configured to produce the second voltage and to output the second voltage to the second subsystem, the battery having at least two battery units having individual voltage taps, (iii) an electrical generator, and (iv) a coupling unit configured to connect the second subsystem to the first subsystem, the individual voltage taps of the at least two battery units being routed to the coupling unit, the coupling unit being configured to selectively connect individual ones of the at least two battery units to the first subsystem, the method comprising:

ascertaining a state of charge of each of the at least two battery units;

operating the coupling unit to connect a battery unit of the at least two battery units that has a highest state of charge to the first subsystem;

drawing power from the second subsystem with the coupling unit; and

supplying the power to the first subsystem with the coupling unit.

7. The method as claimed in claim 6, further comprising:

operating the coupling unit to change which of the at least two battery units is connected to the first subsystem in response to a charge difference of the at least two battery units exceeding a threshold value.

8. The method as claimed in claim 6, further comprising:

disconnecting a current-carrying battery unit of the at least two battery units; and

connecting, thereafter, a selected further battery unit of the at least two battery units.

9. The method as claimed in claim 6, wherein the method is performed by a computer program that is executed on a programmable computer device.

10. A motor vehicle comprising:

an internal combustion engine; and

an onboard electrical system, the onboard electrical system comprising;

a first subsystem having at least one first load configured to operate with a first voltage;

a second subsystem having at least one second load configured to operate with a second voltage, the second voltage being higher than the first voltage, the second subsystem having a battery configured to produce the second voltage and to output the second voltage to the second subsystem, the battery having at least two battery units having individual voltage taps;

an electrical generator;

a coupling unit configured to connect the second subsystem to the first subsystem, the coupling unit being configured to draw power from the second subsystem and to supply the power to the first subsystem, the individual voltage taps of the at least two battery units being routed to the coupling unit, the coupling unit being configured to selectively connect individual ones of the at least two battery units to the first subsystem; and

a controller operably connected to the coupling unit, the controller being configured to (i) ascertain a state of charge of each of the at least two battery units and (ii) operate the coupling unit to connect a battery unit of the at least two battery units that has a highest state of charge to the first subsystem.