EP4018520A1 - Battery system for a motor vehicle for balancing battery modules, method for operating a battery system and motor vehicle - Google Patents
Battery system for a motor vehicle for balancing battery modules, method for operating a battery system and motor vehicleInfo
- Publication number
- EP4018520A1 EP4018520A1 EP20747391.9A EP20747391A EP4018520A1 EP 4018520 A1 EP4018520 A1 EP 4018520A1 EP 20747391 A EP20747391 A EP 20747391A EP 4018520 A1 EP4018520 A1 EP 4018520A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- switching element
- battery module
- switching
- connection
- battery
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 25
- 239000003990 capacitor Substances 0.000 claims abstract description 62
- 230000005669 field effect Effects 0.000 claims description 3
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J1/00—Circuit arrangements for DC mains or DC distribution networks
- H02J1/08—Three-wire systems; Systems having more than three wires
- H02J1/082—Plural DC voltage, e.g. DC supply voltage with at least two different DC voltage levels
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
- H01M10/4264—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing with capacitors
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
- H02J7/0014—Circuits for equalisation of charge between batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
- H01M2010/4271—Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2220/00—Batteries for particular applications
- H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2310/00—The network for supplying or distributing electric power characterised by its spatial reach or by the load
- H02J2310/40—The network being an on-board power network, i.e. within a vehicle
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
Definitions
- the invention relates to a battery system for a motor vehicle, which has a first battery module, which has a first voltage source, a first inductance, a positive pole and a negative pole, a second battery module, which has a second voltage source, a second inductance, a positive pole and a has negative pole, an output capacitor which has a positive terminal and a negative terminal, a first switching unit assigned to the first battery module for electrically connecting the first battery module to the output capacitor, and a second switching unit assigned to the second battery module for electrically connecting the second battery module to the Includes output capacitor.
- the invention also relates to a method for operating a battery system according to the invention and to a motor vehicle that has a corresponding battery system.
- Conventional motor vehicles have a drive which usually comprises an internal combustion engine. Furthermore, conventional motor vehicles include a battery system for supplying a starter and other consumers of the motor vehicle with electrical energy and a generator for charging the battery system. Electric vehicles have a battery system for supplying a traction motor and other consumers with electrical energy.
- a generic battery system of a conventional motor vehicle comprises at least two battery modules with at least one, preferably with several battery cells, which are for example connected in series.
- Such a battery module has a nominal voltage of 12 V, 24 V or 48 V, for example.
- An output voltage of a battery system of a conventional motor vehicle corresponds to the nominal voltage of the battery modules, which are connected in parallel.
- a generic battery system of an electric vehicle can also have a higher output voltage of 600 V, for example.
- a generic battery system also includes an output capacitor, which is used to buffer the output voltage of the battery system. Such an output capacitor is electrically connected to an on-board network of the motor vehicle and is also referred to as an intermediate circuit capacitor.
- a generic battery system also comprises at least two switching units for electrically connecting the battery modules to the output capacitor. By means of the switching units, the battery modules can be electrically connected to the on-board network of the motor vehicle and to the output capacitor, as well as being separated from the on-board network and the output capacitor.
- the battery cells of the battery modules are, for example, lithium-ion battery cells.
- the discharge of the battery cells of the battery modules does not necessarily take place evenly.
- the charges of the battery cells, and thus also the charges of the battery modules, can therefore differ from one another, and the voltages of the battery modules are then not all at the same level.
- the charge states of the battery modules must be at least approximately the same. Therefore, the charge states of the individual battery modules are regularly adjusted. Such an adjustment is also referred to as balancing.
- the document EP 2 575 246 A1 discloses a DC voltage converter with a high-voltage side and a low-voltage side, as well as a method for discharging a capacitor on the high-voltage side by means of a transformer.
- Document US 2019/058430 A1 discloses a device which has an electric motor, two voltage sources and a plurality of converters for controlling the electric motor.
- a hybrid drive train system which has a high-voltage battery and contains a DC coupling which is coupled to a rectifier / inverter module.
- the rectifier / inverter module is electrically connected to two torque machines and includes a switch device which includes a pair of power transistors.
- WO 2017/064820 A1 discloses a system for generating electrical energy which comprises a generator, a frequency converter and an energy conversion system.
- a battery system for a motor vehicle comprises a first battery module, which has a first voltage source, a first inductance, a positive pole and a negative pole, a second battery module, which has a second voltage source, a second inductance, a positive pole and a negative pole, an output capacitor , which has a positive terminal and a negative terminal, a first switching unit assigned to the first battery module for electrically connecting the first battery module to the output capacitor and a second switching unit assigned to the second battery module for electrically connecting the second battery module to the output capacitor.
- the battery modules each include a plurality of battery cells that can be connected to one another both in series and in parallel within the battery modules.
- the battery cells are preferably designed as lithium ion battery cells.
- the battery cells simulate electrical cell voltage sources.
- Electrical lines within the battery modules have inductances.
- the electrical cell voltage sources of the battery cells of a battery module each form the voltage source of the respective battery module.
- the inductance of the electrical lines of a battery module forms the inductance of the respective battery module.
- the battery modules can also have a coil with an additional inductance.
- Said output capacitor is, for example, an intermediate circuit capacitor.
- the intermediate circuit capacitor can be electrically connected to an on-board network of the motor vehicle and serves to buffer a Output voltage of the battery system.
- the battery module can also have a further capacitor.
- each of the switching units has a first switching element, a second switching element and a third switching element.
- the switching elements each have three connections, a switching path being formed between a first connection and a second connection, which can be controlled by means of a third connection.
- the switching units are preferably constructed identically and connected in the same way to the respectively assigned battery module and to the output capacitor.
- a first connection of the first switching element is connected to a junction, and a second connection of the first switching element is connected to one of the poles of the assigned battery module.
- a first connection of the second switching element is connected to the node, and a second connection of the second switching element is connected to one of the terminals of the output capacitor.
- a first connection of the third switching element is connected to the other of the poles of the associated battery module and to the other of the terminals of the output capacitor, and a second connection of the third switching element is connected to the junction.
- the second connection of the first switching element is connected to the positive pole of the associated battery module, and the second connection of the second switching element is connected to the positive terminal of the output capacitor.
- the first connection of the third switching element is then connected to the negative pole of the assigned battery module and to the negative terminal of the output capacitor.
- the negative pole of the battery module is permanently connected to the negative terminal of the output capacitor.
- each of the two battery modules can be electrically connected to the on-board network of the motor vehicle and to the output capacitor, as well as being disconnected from the on-board network and the output capacitor.
- the first switching element and the second switching element are closed and the third switching element is open, so the respective battery module is connected to the vehicle electrical system and to the output capacitor. If both battery modules are connected to the vehicle electrical system and to the output capacitor, they are connected in parallel.
- the battery system can also comprise more than two battery modules, each with an assigned switching unit.
- the first switching element, the second switching element and the third switching element of the switching units are each designed as field effect transistors and each have a SOURCE connection, a DRAIN connection and a GATE connection.
- the switching elements are connected in such a way that the first connection is the SOURCE connection, the second connection is the DRAIN connection and the third connection is the GATE connection.
- the switching elements are MOSFETs, in particular n-channel MOSFETs of the enhancement type.
- the first switching element, the second switching element and the third switching element of the two switching units each have a switching path and an inverse diode connected in parallel to the switching path, which is also referred to as a body diode.
- a method for operating a battery system according to the invention is also proposed.
- the second switching unit is activated in such a way that a current flows through the second battery module, whereby electrical energy is transmitted to the second voltage source of the second battery module.
- the current flows through the second switching unit, through the second inductance and through the second voltage source, among other things.
- the battery cells of the second battery module are charged. This increases the state of charge of the second battery module and the voltage of the second voltage source of the second battery module increases. If the state of charge of the second battery module is lower than the state of charge of the first battery module, then the method according to the invention brings about an equalization of the charge states, that is, a balancing of the two battery modules.
- the electrical energy that is transmitted to the second voltage source of the second battery module is preferably taken from the first battery module and / or the output capacitor and is transmitted to the second voltage source of the second battery module by said current.
- the state of charge of the first battery module drops at the same time. This further accelerates the equalization of the charge states, i.e. the balancing of the two battery modules.
- the second switching unit is preferably activated in several successive phases.
- the second switching unit is controlled in such a way that, during a first phase, electrical energy is transmitted from the first battery module to the second inductance of the second battery module, and during a second phase, electrical energy is transmitted from the second inductance of the second battery module to the second voltage source of the second battery module is transmitted.
- the second switching unit is preferably controlled in such a way that, during a first phase, the first switching element of the second switching unit is closed, the second switching element of the second switching unit is closed and the third switching element of the second switching unit is opened.
- the current flows through the first switching element, through the second switching element, through the second inductance and through the second voltage source.
- the second switching unit is preferably further controlled in such a way that, during a second phase, the first switching element of the second switching unit is closed, the second switching element of the second switching unit is opened and the third switching element of the second switching unit is closed.
- the current flows through the first switching element, through the third switching element, through the second inductance and through the second voltage source.
- the second switching unit is also preferably controlled in such a way that the first phase and the second phase are repeated cyclically.
- the first phase and the second phase are preferably repeated at a relatively high frequency of, for example, 20 kHz.
- a motor vehicle which comprises at least one battery system according to the invention, which is operated with the method according to the invention.
- the battery system according to the invention can be operated in a manner similar to a DC / DC converter, or like a buck converter.
- electrical energy is transmitted in particular from the first voltage source to the internal inductances and on to the second voltage source.
- the voltage of the second voltage source always remains less than or equal to the voltage of the first voltage source.
- Figure 1 is a schematic representation of a battery system
- FIG. 2 shows a schematic representation of the battery system during a first phase of the method
- FIG. 3 shows a schematic representation of the battery system during a second phase of the method.
- FIG. 1 shows a schematic representation of a battery system 10 for a motor vehicle.
- the battery system 10 comprises a first battery module 5, a second battery module 6, an output capacitor CA, a first switching unit 50 assigned to the first battery module 5, and a second switching unit 60 assigned to the second battery module 6.
- the first switching unit 50 is used to electrically connect the first battery module 5 with the output capacitor CA.
- the second switching unit 60 serves to electrically connect the second battery module 6 to the output capacitor CA.
- the battery modules 5, 6 each include a plurality of battery cells, not shown here, which can be connected to one another both in series and in parallel within the respective battery module 5, 6. Each of the battery cells simulates an electrical cell voltage source.
- the electrical cell voltage sources of the battery cells each form a voltage source VI, V2 of the respective battery module 5, 6.
- Inductances of electrical lines of the battery modules 5, 6 form inductances LI, L2. Additional coils with an additional inductance can optionally be provided.
- the inductances of the electrical lines together with the inductances of the coils form the inductances LI, L2.
- the first battery module 5 thus has the first voltage source VI and the first inductance LI.
- the first battery module 5 also has a positive pole 22 and a negative pole 21. When idling, a voltage supplied by the first voltage source VI is applied between the positive pole 22 and the negative pole 21.
- the second battery module 6 thus has the second voltage source V2 and the second inductance L2.
- the second battery module 6 also has a positive pole 22 and a negative pole 21. When idling, a voltage supplied by the second voltage source V2 is applied between the positive pole 22 and the negative pole 21.
- the output capacitor CA has a positive terminal 12 and a negative terminal 11.
- the output capacitor CA is, for example, an intermediate circuit capacitor which is electrically connected to an on-board network of the motor vehicle.
- the battery modules 5, 6 can have further capacitors, which together with the intermediate circuit capacitor then form the output capacitor CA.
- the first switching unit 50 and the second switching unit 60 are constructed identically in the present case.
- the switching units 50, 60 each have a first switching element 61, a second switching element 62 and a third switching element 63.
- the switching elements 61, 62, 63 each have three connections, a switching path being formed between a first connection and a second connection, which can be controlled by means of a third connection.
- the switching units 50, 60 each have an internal node 25.
- the first switching element 61, the second switching element 62 and the third switching element 63 are in the present case designed as field effect transistors.
- the switching elements 61, 62, 63 each have a SOURCE connection, a DRAIN connection and a GATE connection.
- the switching elements 61, 62, 63 are connected in such a way that the first connection is the SOURCE connection, the second connection is the DRAIN connection and the third connection is the GATE connection.
- the switching elements 61, 62, 63 are in the present case n-channel MOSFETs of the enhancement type.
- the switching elements 61, 62, 63 each have a switching path and an inverse diode connected in parallel to the switching path.
- the inverse diode which is also referred to as a body diode, is created in every MOSFET due to its internal structure and is not an explicit component.
- the first connection of the first switching element 61 is connected to the node 25.
- a second connection of the first switching element 61 is connected to the positive pole 22 of the associated battery module 5, 6.
- a first connection of the second switching element 62 is connected to the node 25.
- a second terminal of the second switching element 62 is connected to the positive terminal 12 of the output capacitor CA.
- a first connection of the third switching element 63 is connected to the negative pole 21 of the associated battery module 5, 6 and to the negative terminal 11 of the output capacitor CA.
- a second connection of the third switching element 63 is connected to the node 25.
- FIG. 2 shows a schematic illustration of the battery system 10 during a first phase of the method.
- the first switching element 61 in the first switching unit 50 is closed, the second switching element 62 is closed and the third switching element 63 is opened.
- the first switching element 61 in the second switching unit 60 is closed, the second switching element 62 is closed and the third switching element 63 is opened.
- a current I flows during the first phase through the second voltage source V2, through the second inductance L2, as well as through the first switching element 61 and through the second switching element 62 of the second switching unit 60.
- the current I also flows through the first voltage source during the first phase VI, through the first inductance LI, as well as through the first switching element 61 and through the second switching element 62 of the first switching unit 50.
- Electrical energy is transmitted from the first voltage source VI to the first inductance LI and to the second inductance L2.
- the state of charge of the first battery module 5 drops in the process.
- the second switching element 62 of the second switching unit 60 is opened and the third switching element 63 of the second switching unit 60 is closed.
- a second phase begins.
- the first switching element 61 of the second switching unit 60 remains closed.
- the first switching element 61 and the second switching element 62 of the first switching unit 50 remain closed, and the third switching element 63 of the first switching unit 50 remains open.
- FIG. 3 shows a schematic representation of the battery system 10 during the second phase of the method.
- the first switching element 61 in the first switching unit 50 is closed, the second switching element 62 is closed and the third switching element 63 is opened.
- the first switching element 61 in the second switching unit 60 is closed, the second switching element 62 is opened and the third switching element 63 is closed.
- a current I flows during the second phase through the second voltage source V2, through the second inductance L2, as well as through the first switching element 61 and through the third switching element 63 of the second switching unit 60. Electrical energy is thereby transferred from the second inductance L2 to the second voltage source V2 of the second battery module 6 is transmitted. The state of charge of the second battery module 6 increases in the process.
- the third switching element 63 of the second switching unit 60 can also remain open during the second phase.
- the third switching element 63 is designed as a MOSFET and has an inverse diode, which is also referred to as a body diode.
- the third switching element 63 is arranged in the second switching unit 60 in such a way that the current I flowing during the second phase can flow through the said inverse diode.
- the second switching element 62 of the second switching unit 60 is closed and the third switching element 63 of the second switching unit 60 is opened.
- Another first phase begins.
- the first switching element 61 of the second switching unit 60 remains closed.
- the first switching element 61 and the second switching element 62 of the first switching unit 50 remain closed, and the third switching element 63 of the first switching unit 50 remains open.
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- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Power Engineering (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
- Electric Propulsion And Braking For Vehicles (AREA)
Abstract
Description
BATTERIESYSTEM FÜR EIN KRAFTFAHRZEUG ZUM BALANCING VON BATTERIEMODULEN , VERFAHREN ZUM BETREIBEN EINES BATTERIESYSTEMS UND KRAFTFAHRZEUG BATTERY SYSTEM FOR A MOTOR VEHICLE FOR BALANCING BATTERY MODULES, METHOD OF OPERATING A BATTERY SYSTEM AND MOTOR VEHICLE
Die Erfindung betrifft ein Batteriesystem für ein Kraftfahrzeug, das ein erstes Batteriemodul, welches eine erste Spannungsquelle, eine erste Induktivität, einen positiven Pol und einen negativen Pol aufweist, ein zweites Batteriemodul, welches eine zweite Spannungsquelle, eine zweite Induktivität, einen positiven Pol und einen negativen Pol aufweist, einen Ausgangskondensator, welcher ein positives Terminal und ein negatives Terminal aufweist, eine dem ersten Batteriemodul zugeordnete erste Schalteinheit zur elektrischen Verbindung des ersten Batteriemoduls mit dem Ausgangskondensator, und eine dem zweiten Batteriemodul zugeordnete zweite Schalteinheit zur elektrischen Verbindung des zweiten Batteriemoduls mit dem Ausgangskondensator umfasst. Die Erfindung betrifft auch ein Verfahren zum Betreiben eines erfindungsgemäßen Batteriesystems sowie ein Kraftfahrzeug, welches ein entsprechendes Batteriesystem aufweist. The invention relates to a battery system for a motor vehicle, which has a first battery module, which has a first voltage source, a first inductance, a positive pole and a negative pole, a second battery module, which has a second voltage source, a second inductance, a positive pole and a has negative pole, an output capacitor which has a positive terminal and a negative terminal, a first switching unit assigned to the first battery module for electrically connecting the first battery module to the output capacitor, and a second switching unit assigned to the second battery module for electrically connecting the second battery module to the Includes output capacitor. The invention also relates to a method for operating a battery system according to the invention and to a motor vehicle that has a corresponding battery system.
Stand der Technik State of the art
Konventionelle Kraftfahrzeuge weisen einen Antrieb auf, welcher üblicherweise einen Verbrennungsmotor umfasst. Ferner umfassen konventionelle Kraftfahrzeuge ein Batteriesystem zur Versorgung eines Anlassers und weiterer Verbraucher des Kraftfahrzeugs mit elektrischer Energie sowie einen Generator zum Laden des Batteriesystems. Elektrofahrzeuge weisen ein Batteriesystem zur Versorgung eines Traktionsmotors und weiterer Verbraucher mit elektrischer Energie auf. Conventional motor vehicles have a drive which usually comprises an internal combustion engine. Furthermore, conventional motor vehicles include a battery system for supplying a starter and other consumers of the motor vehicle with electrical energy and a generator for charging the battery system. Electric vehicles have a battery system for supplying a traction motor and other consumers with electrical energy.
Ein gattungsgemäßes Batteriesystem eines konventionellen Kraftfahrzeugs umfasst mindestens zwei Batteriemodule mit mindestens einer, vorzugsweise mit mehreren Batteriezellen, die beispielsweise seriell verschaltet sind. Ein solches Batteriemodul weist eine Nominalspannung von beispielsweise 12 V, 24 V oder 48 V auf. Eine Ausgangsspannung eines Batteriesystems eines konventionellen Kraftfahrzeugs entspricht dabei der Nominalspannung der Batteriemodule, welche parallel verschaltet sind. Ein gattungsgemäßes Batteriesystem eines Elektrofahrzeugs kann auch eine höhere Ausgangsspannung von beispielsweise 600 V aufweisen. A generic battery system of a conventional motor vehicle comprises at least two battery modules with at least one, preferably with several battery cells, which are for example connected in series. Such a battery module has a nominal voltage of 12 V, 24 V or 48 V, for example. An output voltage of a battery system of a conventional motor vehicle corresponds to the nominal voltage of the battery modules, which are connected in parallel. A generic battery system of an electric vehicle can also have a higher output voltage of 600 V, for example.
Ein gattungsgemäßes Batteriesystem umfasst auch einen Ausgangskondensator, welcher zur Pufferung der Ausgangsspannung des Batteriesystems dient. Ein solcher Ausgangskondensator ist elektrisch mit einem Bordnetz des Kraftfahrzeugs verbunden und wird auch als Zwischenkreiskondensator bezeichnet. Ein gattungsgemäßes Batteriesystem umfasst ferner mindestens zwei Schalteinheiten zur elektrischen Verbindung der Batteriemodule mit dem Ausgangskondensator. Mittels der Schalteinheiten können die Batteriemodule elektrisch mit dem Bordnetz des Kraftfahrzeugs und mit dem Ausgangskondensator verbunden, sowie von dem Bordnetz und dem Ausgangskondensator getrennt werden. A generic battery system also includes an output capacitor, which is used to buffer the output voltage of the battery system. Such an output capacitor is electrically connected to an on-board network of the motor vehicle and is also referred to as an intermediate circuit capacitor. A generic battery system also comprises at least two switching units for electrically connecting the battery modules to the output capacitor. By means of the switching units, the battery modules can be electrically connected to the on-board network of the motor vehicle and to the output capacitor, as well as being separated from the on-board network and the output capacitor.
Bei den Batteriezellen der Batteriemodule handelt es sich beispielsweise um Lithium-Ionen-Batteriezellen. Die Entladung der Batteriezellen der Batteriemodule findet dabei nicht zwingend gleichmäßig statt. Die Ladungen der Batteriezellen, und damit auch die Ladungen der Batteriemodule, können somit voneinander abweichen, und die Spannungen der Batteriemodule liegen dann nicht alle auf dem gleichen Niveau. Zum Betrieb eines solchen Batteriesystems müssen die Ladungszustände der Batteriemodule zumindest annähernd gleich sein. Daher findet regelmäßig eine Angleichung der Ladungszustände der einzelnen Batteriemodule statt. Ein solcher Ausgleich wird auch als Balancing bezeichnet. The battery cells of the battery modules are, for example, lithium-ion battery cells. The discharge of the battery cells of the battery modules does not necessarily take place evenly. The charges of the battery cells, and thus also the charges of the battery modules, can therefore differ from one another, and the voltages of the battery modules are then not all at the same level. To operate such a battery system, the charge states of the battery modules must be at least approximately the same. Therefore, the charge states of the individual battery modules are regularly adjusted. Such an adjustment is also referred to as balancing.
Das Dokument EP 2 575 246 Al offenbart einen Gleichspannungswandler mit einer Hochspannungsseite und einer Niederspannungsseite, sowie ein Verfahren zum Entladen eines Kondensators der Hochspannungsseite mittels eines Transformators. The document EP 2 575 246 A1 discloses a DC voltage converter with a high-voltage side and a low-voltage side, as well as a method for discharging a capacitor on the high-voltage side by means of a transformer.
In dem Dokument US 2019/058430 Al ist eine Vorrichtung offenbart, welche einen Elektromotor, zwei Spannungsquellen und eine Mehrzahl von Umrichtern zum Ansteuern des Elektromotors aufweist. Document US 2019/058430 A1 discloses a device which has an electric motor, two voltage sources and a plurality of converters for controlling the electric motor.
Aus den Dokumenten DE 10 2011 110 906 Al und CN 102 39 8507 B ist ein Hybridantriebsstrangsystem bekannt, welches eine Hochspannungsbatterie und eine DC-Kopplung enthält, welche mit einem Gleichrichter/Wechselrichter-Modul gekoppelt ist. Das Gleichrichter/Wechselrichter-Modul ist mit zwei Drehmomentmaschinen elektrisch verbunden und umfasst eine Schaltereinrichtung, welche ein Paar von Leistungstransistoren umfasst. From the documents DE 10 2011 110 906 Al and CN 102 39 8507 B, a hybrid drive train system is known which has a high-voltage battery and contains a DC coupling which is coupled to a rectifier / inverter module. The rectifier / inverter module is electrically connected to two torque machines and includes a switch device which includes a pair of power transistors.
Das Dokument WO 2017/064820 Al offenbart ein System zur Erzeugung von elektrischer Energie, welches einen Generator, einen Frequenzumrichter und ein Energieumwandlungssystem umfasst. The document WO 2017/064820 A1 discloses a system for generating electrical energy which comprises a generator, a frequency converter and an energy conversion system.
Offenbarung der Erfindung Disclosure of the invention
Es wird ein Batteriesystem für ein Kraftfahrzeug vorgeschlagen. Das Batteriesystem umfasst dabei ein erstes Batteriemodul, welches eine erste Spannungsquelle, eine erste Induktivität, einen positiven Pol und einen negativen Pol aufweist, ein zweites Batteriemodul, welches eine zweite Spannungsquelle, eine zweite Induktivität, einen positiven Pol und einen negativen Pol aufweist, einen Ausgangskondensator, welcher ein positives Terminal und ein negatives Terminal aufweist, eine dem ersten Batteriemodul zugeordnete erste Schalteinheit zur elektrischen Verbindung des ersten Batteriemoduls mit dem Ausgangskondensator und eine dem zweiten Batteriemodul zugeordnete zweite Schalteinheit zur elektrischen Verbindung des zweiten Batteriemoduls mit dem Ausgangskondensator. A battery system for a motor vehicle is proposed. The battery system comprises a first battery module, which has a first voltage source, a first inductance, a positive pole and a negative pole, a second battery module, which has a second voltage source, a second inductance, a positive pole and a negative pole, an output capacitor , which has a positive terminal and a negative terminal, a first switching unit assigned to the first battery module for electrically connecting the first battery module to the output capacitor and a second switching unit assigned to the second battery module for electrically connecting the second battery module to the output capacitor.
Die Batteriemodule umfassen jeweils mehrere Batteriezellen, die innerhalb der Batteriemodule sowohl seriell als auch parallel miteinander verschaltetet sein können. Die Batteriezellen sind vorzugsweise als Lithium- lonen-Batteriezellen ausgeführt. Die Batteriezellen bilden elektrische Zellspannungsquellen nach. Elektrische Leitungen innerhalb der Batteriemodule weisen Induktivitäten auf. Die elektrischen Zellspannungsquellen der Batteriezellen eines Batteriemoduls bilden jeweils die Spannungsquelle des jeweiligen Batteriemoduls. Die Induktivität der elektrischen Leitungen eines Batteriemoduls bildet jeweils die Induktivität des jeweiligen Batteriemoduls. Optional können die Batteriemodule zusätzlich eine Spule mit einer zusätzlichen Induktivität aufweisen. The battery modules each include a plurality of battery cells that can be connected to one another both in series and in parallel within the battery modules. The battery cells are preferably designed as lithium ion battery cells. The battery cells simulate electrical cell voltage sources. Electrical lines within the battery modules have inductances. The electrical cell voltage sources of the battery cells of a battery module each form the voltage source of the respective battery module. The inductance of the electrical lines of a battery module forms the inductance of the respective battery module. Optionally, the battery modules can also have a coil with an additional inductance.
Bei dem besagten Ausgangskondensator handelt es sich beispielsweise um einen Zwischenkreiskondensator. Der Zwischenkreiskondensator ist elektrisch mit einem Bordnetz des Kraftfahrzeugs verbindbar und dient zur Pufferung einer Ausgangsspannung des Batteriesystems. Alternativ oder zusätzlich zu dem Zwischenkreiskondensator kann das Batteriemodul zusätzlich einen weiteren Kondensator aufweisen. Said output capacitor is, for example, an intermediate circuit capacitor. The intermediate circuit capacitor can be electrically connected to an on-board network of the motor vehicle and serves to buffer a Output voltage of the battery system. As an alternative or in addition to the intermediate circuit capacitor, the battery module can also have a further capacitor.
Erfindungsgemäß weist jede der Schalteinheiten jeweils ein erstes Schaltelement, ein zweites Schaltelement und ein drittes Schaltelement auf. Die Schaltelemente weisen jeweils drei Anschlüsse auf, wobei zwischen einem ersten Anschluss und einem zweiten Anschluss eine Schaltstrecke gebildet ist, welche mittels eines dritten Anschlusses ansteuerbar ist. Die Schalteinheiten sind vorzugsweise identisch aufgebaut und auf gleiche Art mit dem jeweils zugeordneten Batteriemodul und mit dem Ausgangskondensator verbunden. According to the invention, each of the switching units has a first switching element, a second switching element and a third switching element. The switching elements each have three connections, a switching path being formed between a first connection and a second connection, which can be controlled by means of a third connection. The switching units are preferably constructed identically and connected in the same way to the respectively assigned battery module and to the output capacitor.
Dabei ist ein erster Anschluss des ersten Schaltelements mit einem Knotenpunkt verbunden, und ein zweiter Anschluss des ersten Schaltelements mit einem der Pole des zugeordneten Batteriemoduls verbunden. Ein erster Anschluss des zweiten Schaltelements ist mit dem Knotenpunkt verbunden, und ein zweiter Anschluss des zweiten Schaltelements mit einem der Terminals des Ausgangskondensators verbunden. Ein erster Anschluss des dritten Schaltelements ist mit dem anderen der Pole des zugeordneten Batteriemoduls und mit dem anderen der Terminals des Ausgangskondensators verbunden, und ein zweiter Anschluss des dritten Schaltelements ist mit dem Knotenpunkt verbunden. A first connection of the first switching element is connected to a junction, and a second connection of the first switching element is connected to one of the poles of the assigned battery module. A first connection of the second switching element is connected to the node, and a second connection of the second switching element is connected to one of the terminals of the output capacitor. A first connection of the third switching element is connected to the other of the poles of the associated battery module and to the other of the terminals of the output capacitor, and a second connection of the third switching element is connected to the junction.
Beispielsweise ist der zweite Anschluss des ersten Schaltelements mit dem positiven Pol des zugeordneten Batteriemoduls verbunden, und der zweite Anschluss des zweiten Schaltelements ist mit dem positiven Terminal des Ausgangskondensators verbunden. Der erste Anschluss des dritten Schaltelements ist dann mit dem negativen Pol des zugeordneten Batteriemoduls und mit dem negativen Terminal des Ausgangskondensators verbunden. Der negative Pol des Batteriemoduls ist dabei mit dem negativen Terminal des Ausgangskondensators fest verbunden. For example, the second connection of the first switching element is connected to the positive pole of the associated battery module, and the second connection of the second switching element is connected to the positive terminal of the output capacitor. The first connection of the third switching element is then connected to the negative pole of the assigned battery module and to the negative terminal of the output capacitor. The negative pole of the battery module is permanently connected to the negative terminal of the output capacitor.
Mittels der zugeordneten Schalteinheit kann jedes der beiden Batteriemodule elektrisch mit dem Bordnetz des Kraftfahrzeugs und mit dem Ausgangskondensator verbunden, sowie von dem Bordnetz und dem Ausgangskondensator getrennt werden. Wenn das erste Schaltelement und das zweite Schaltelement geschlossen sind und das dritte Schaltelement geöffnet ist, so ist das jeweilige Batteriemodul mit dem Bordnetz und mit dem Ausgangskondensator verbunden. Wenn beide Batteriemodule mit dem Bordnetz und mit dem Ausgangskondensator verbunden sind, so sind diese parallel verschaltet. Das Batteriesystem kann auch mehr als zwei Batteriemodule mit jeweils einer zugeordneten Schalteinheit umfassen. By means of the associated switching unit, each of the two battery modules can be electrically connected to the on-board network of the motor vehicle and to the output capacitor, as well as being disconnected from the on-board network and the output capacitor. When the first switching element and the second switching element are closed and the third switching element is open, so the respective battery module is connected to the vehicle electrical system and to the output capacitor. If both battery modules are connected to the vehicle electrical system and to the output capacitor, they are connected in parallel. The battery system can also comprise more than two battery modules, each with an assigned switching unit.
Gemäß einer bevorzugten Ausgestaltung der Erfindung sind das erste Schaltelement, das zweite Schaltelement und das dritte Schaltelement der Schalteinheiten jeweils als Feldeffekttransistoren ausgebildet und weisen jeweils einen SOURCE-Anschluss, einen DRAIN-Anschluss und einen GATE-Anschluss auf. Die Schaltelemente sind derart verschaltet, dass jeweils der erste Anschluss der SOURCE-Anschluss, der zweite Anschluss der DRAIN-Anschluss und der dritte Anschluss der GATE-Anschluss ist. Beispielsweise handelt es sich bei den Schaltelementen um MOSFETs, insbesondere um n-Kanal-MOSFETs vom Anreicherungstyp. According to a preferred embodiment of the invention, the first switching element, the second switching element and the third switching element of the switching units are each designed as field effect transistors and each have a SOURCE connection, a DRAIN connection and a GATE connection. The switching elements are connected in such a way that the first connection is the SOURCE connection, the second connection is the DRAIN connection and the third connection is the GATE connection. For example, the switching elements are MOSFETs, in particular n-channel MOSFETs of the enhancement type.
Vorzugsweise weisen das erste Schaltelement, das zweite Schaltelement und das dritte Schaltelement der beiden Schalteinheiten jeweils eine Schaltstrecke sowie eine parallel zu der Schaltstrecke geschaltete Inversdiode, welche auch als Body-Diode bezeichnet wird, auf. Preferably, the first switching element, the second switching element and the third switching element of the two switching units each have a switching path and an inverse diode connected in parallel to the switching path, which is also referred to as a body diode.
Es wird auch ein Verfahren zum Betreiben eines erfindungsgemäßen Batteriesystems vorgeschlagen. Dabei wird die zweite Schalteinheit derart angesteuert, dass ein Strom durch das zweite Batteriemodul fließt, wodurch elektrische Energie zu der zweiten Spannungsquelle des zweiten Batteriemoduls übertragen wird. Der Strom fließt dabei unter anderem durch die zweite Schalteinheit, durch die zweite Induktivität und durch die zweite Spannungsquelle. A method for operating a battery system according to the invention is also proposed. The second switching unit is activated in such a way that a current flows through the second battery module, whereby electrical energy is transmitted to the second voltage source of the second battery module. The current flows through the second switching unit, through the second inductance and through the second voltage source, among other things.
Durch die Übertragung der elektrischen Energie zu der zweiten Spannungsquelle des zweiten Batteriemoduls erfolgt eine Aufladung der Batteriezellen des zweiten Batteriemoduls. Damit steigt der Ladungszustand des zweiten Batteriemoduls an, und die Spannung der zweiten Spannungsquelle des zweiten Batteriemoduls wird größer. Wenn der Ladungszustand des zweiten Batteriemoduls geringer als der Ladungszustand des ersten Batteriemoduls ist, so erfolgt durch das erfindungsgemäße Verfahren eine Angleichung der Ladungszustände, also ein Balancing der beiden Batteriemodule. Vorzugsweise wird die elektrische Energie, die zu der zweiten Spannungsquelle des zweiten Batteriemoduls übertragen wird, dem ersten Batteriemodul und/oder dem Ausgangskondensator entnommen und durch den besagten Strom zu der zweiten Spannungsquelle des zweiten Batteriemoduls übertragen. By transmitting the electrical energy to the second voltage source of the second battery module, the battery cells of the second battery module are charged. This increases the state of charge of the second battery module and the voltage of the second voltage source of the second battery module increases. If the state of charge of the second battery module is lower than the state of charge of the first battery module, then the method according to the invention brings about an equalization of the charge states, that is, a balancing of the two battery modules. The electrical energy that is transmitted to the second voltage source of the second battery module is preferably taken from the first battery module and / or the output capacitor and is transmitted to the second voltage source of the second battery module by said current.
Wenn die elektrische Energie, die zu der zweiten Spannungsquelle des zweiten Batteriemoduls übertragen wird, dem ersten Batteriemodul entnommen wird, so sinkt gleichzeitig der Ladungszustand des ersten Batteriemoduls. Dadurch wird die Angleichung der Ladungszustände, also das Balancing der beiden Batteriemodule, weiter beschleunigt. When the electrical energy that is transmitted to the second voltage source of the second battery module is drawn from the first battery module, the state of charge of the first battery module drops at the same time. This further accelerates the equalization of the charge states, i.e. the balancing of the two battery modules.
Bevorzugt wird die zweite Schalteinheit in mehreren aufeinanderfolgenden Phasen angesteuert. Dabei wird die zweite Schalteinheit derart angesteuert, dass während einer ersten Phase elektrische Energie von dem ersten Batteriemodul zu der zweiten Induktivität des zweiten Batteriemoduls übertragen wird, und während einer zweiten Phase elektrische Energie von der zweiten Induktivität des zweiten Batteriemoduls zu der zweiten Spannungsquelle des zweiten Batteriemoduls übertragen wird. The second switching unit is preferably activated in several successive phases. The second switching unit is controlled in such a way that, during a first phase, electrical energy is transmitted from the first battery module to the second inductance of the second battery module, and during a second phase, electrical energy is transmitted from the second inductance of the second battery module to the second voltage source of the second battery module is transmitted.
Vorzugsweise wird die zweite Schalteinheit derart angesteuert, dass während einer ersten Phase das erste Schaltelement der zweiten Schalteinheit geschlossen, das zweite Schaltelement der zweiten Schalteinheit geschlossen und das dritte Schaltelement der zweiten Schalteinheit geöffnet ist. Der Strom fließt während der ersten Phase durch das erste Schaltelement, durch das zweite Schaltelement, durch die zweite Induktivität und durch die zweite Spannungsquelle. The second switching unit is preferably controlled in such a way that, during a first phase, the first switching element of the second switching unit is closed, the second switching element of the second switching unit is closed and the third switching element of the second switching unit is opened. During the first phase, the current flows through the first switching element, through the second switching element, through the second inductance and through the second voltage source.
Vorzugsweise wird die die zweite Schalteinheit ferner derart angesteuert, dass während einer zweiten Phase das erste Schaltelement der zweiten Schalteinheit geschlossen, das zweite Schaltelement der zweiten Schalteinheit geöffnet und das dritte Schaltelement der zweiten Schalteinheit geschlossen ist. Der Strom fließt während der zweiten Phase durch das erste Schaltelement, durch das dritte Schaltelement, durch die zweite Induktivität und durch die zweite Spannungsquelle. Vorzugsweise wird die zweite Schalteinheit ferner derart angesteuert, dass die erste Phase und die zweite Phase zyklisch wiederholt werden. Die erste Phase und die zweite Phase werden bevorzugt mit einer verhältnismäßig hohen Frequenz von beispielsweise 20 kHz wiederholt. The second switching unit is preferably further controlled in such a way that, during a second phase, the first switching element of the second switching unit is closed, the second switching element of the second switching unit is opened and the third switching element of the second switching unit is closed. During the second phase, the current flows through the first switching element, through the third switching element, through the second inductance and through the second voltage source. The second switching unit is also preferably controlled in such a way that the first phase and the second phase are repeated cyclically. The first phase and the second phase are preferably repeated at a relatively high frequency of, for example, 20 kHz.
Es wird auch ein Kraftfahrzeug vorgeschlagen, das mindestens ein erfindungsgemäßes Batteriesystem umfasst, welches mit dem erfindungsgemäßen Verfahren betrieben wird. A motor vehicle is also proposed which comprises at least one battery system according to the invention, which is operated with the method according to the invention.
Vorteile der Erfindung Advantages of the invention
Mittels des erfindungsgemäßen Verfahrens ist es möglich, in einem erfindungsgemäßen Batteriesystem für ein Kraftfahrzeug die Ladungszustände der Batteriemodule verhältnismäßig einfach und in verhältnismäßig kurzer Zeit anzugleichen, also ein Balancing durchzuführen. Dabei kann insbesondere Energie, und damit auch elektrische Ladung, von einem Batteriemodul mit einem höheren Ladungszustand auf ein Batteriemodul mit einem geringeren Ladungszustand übertragen werden. Der Strom, der durch das zweite Batteriemodul fließt, kann dabei durch entsprechende Ansteuerung der Schaltelemente der zweiten Schalteinheit verhältnismäßig einfach begrenzt werden. By means of the method according to the invention, it is possible, in a battery system according to the invention for a motor vehicle, to equalize the charge states of the battery modules relatively easily and in a relatively short time, that is to say to carry out balancing. In particular, energy, and thus also electrical charge, can be transferred from a battery module with a higher state of charge to a battery module with a lower state of charge. The current that flows through the second battery module can be limited relatively easily by appropriate control of the switching elements of the second switching unit.
Mittels des erfindungsgemäßen Verfahrens kann das erfindungsgemäße Batteriesystem ähnlich wie ein DC/DC-Wandler, beziehungsweise wie ein Tiefsetzsteller, betrieben werden. Während dieses Vorgangs wird elektrische Energie insbesondere von der ersten Spannungsquelle zu den internen Induktivitäten und weiter zu der zweiten Spannungsquelle übertragen. Dabei bleibt die Spannung der zweiten Spannungsquelle stets kleiner oder gleich der Spannung der ersten Spannungsquelle. By means of the method according to the invention, the battery system according to the invention can be operated in a manner similar to a DC / DC converter, or like a buck converter. During this process, electrical energy is transmitted in particular from the first voltage source to the internal inductances and on to the second voltage source. The voltage of the second voltage source always remains less than or equal to the voltage of the first voltage source.
Kurze Beschreibung der Zeichnungen Brief description of the drawings
Ausführungsformen der Erfindung werden anhand der Zeichnungen und der nachfolgenden Beschreibung näher erläutert. Embodiments of the invention are explained in more detail with reference to the drawings and the following description.
Es zeigen: Figur 1 eine schematische Darstellung eines Batteriesystems, Show it: Figure 1 is a schematic representation of a battery system,
Figur 2 eine schematische Darstellung des Batteriesystems während einer ersten Phase des Verfahrens und FIG. 2 shows a schematic representation of the battery system during a first phase of the method and FIG
Figur 3 eine schematische Darstellung des Batteriesystems während einer zweiten Phase des Verfahrens. FIG. 3 shows a schematic representation of the battery system during a second phase of the method.
Ausführungsformen der Erfindung Embodiments of the invention
In der nachfolgenden Beschreibung der Ausführungsformen der Erfindung werden gleiche oder ähnliche Elemente mit gleichen Bezugszeichen bezeichnet, wobei auf eine wiederholte Beschreibung dieser Elemente in Einzelfällen verzichtet wird. Die Figuren stellen den Gegenstand der Erfindung nur schematisch dar. In the following description of the embodiments of the invention, the same or similar elements are denoted by the same reference numerals, a repeated description of these elements being dispensed with in individual cases. The figures represent the subject matter of the invention only schematically.
Figur 1 zeigt eine schematische Darstellung eines Batteriesystems 10 für ein Kraftfahrzeug. Das Batteriesystem 10 umfasst ein erstes Batteriemodul 5, ein zweites Batteriemodul 6, einen Ausgangskondensator CA, eine dem ersten Batteriemodul 5 zugeordnete erste Schalteinheit 50 und eine dem zweiten Batteriemodul 6 zugeordnete zweite Schalteinheit 60. Die erste Schalteinheit 50 dient zur elektrischen Verbindung des ersten Batteriemoduls 5 mit dem Ausgangskondensator CA. Die zweite Schalteinheit 60 dient zur elektrischen Verbindung des zweiten Batteriemoduls 6 mit dem Ausgangskondensator CA. FIG. 1 shows a schematic representation of a battery system 10 for a motor vehicle. The battery system 10 comprises a first battery module 5, a second battery module 6, an output capacitor CA, a first switching unit 50 assigned to the first battery module 5, and a second switching unit 60 assigned to the second battery module 6. The first switching unit 50 is used to electrically connect the first battery module 5 with the output capacitor CA. The second switching unit 60 serves to electrically connect the second battery module 6 to the output capacitor CA.
Die Batteriemodule 5, 6 umfasst jeweils mehrere hier nicht dargestellte Batteriezellen, die innerhalb des jeweiligen Batteriemoduls 5, 6 sowohl seriell als auch parallel miteinander verschaltetet sein können. Jede der Batteriezellen bildet eine elektrische Zellspannungsquelle nach. Die elektrischen Zellspannungsquellen der Batteriezellen bilden jeweils eine Spannungsquelle VI, V2 des jeweiligen Batteriemoduls 5, 6. Induktivitäten von elektrischen Leitungen der Batteriemodule 5, 6 bilden Induktivitäten LI, L2. Optional können zusätzlich Spulen mit einer zusätzlichen Induktivität vorgesehen sein. In diesem Fall bilden die Induktivitäten der elektrischen Leitungen gemeinsam mit den Induktivitäten der Spulen die Induktivitäten LI, L2. Das erste Batteriemodul 5 weist somit die erste Spannungsquelle VI und die erste Induktivität LI auf. Das erste Batteriemodul 5 weist ferner einen positiven Pol 22 und einen negativen Pol 21 auf. Im Leerlauf liegt eine von der ersten Spannungsquelle VI gelieferte Spannung zwischen dem positiven Pol 22 und dem negativen Pol 21 an. The battery modules 5, 6 each include a plurality of battery cells, not shown here, which can be connected to one another both in series and in parallel within the respective battery module 5, 6. Each of the battery cells simulates an electrical cell voltage source. The electrical cell voltage sources of the battery cells each form a voltage source VI, V2 of the respective battery module 5, 6. Inductances of electrical lines of the battery modules 5, 6 form inductances LI, L2. Additional coils with an additional inductance can optionally be provided. In this case, the inductances of the electrical lines together with the inductances of the coils form the inductances LI, L2. The first battery module 5 thus has the first voltage source VI and the first inductance LI. The first battery module 5 also has a positive pole 22 and a negative pole 21. When idling, a voltage supplied by the first voltage source VI is applied between the positive pole 22 and the negative pole 21.
Das zweite Batteriemodul 6 weist somit die zweite Spannungsquelle V2 und die zweite Induktivität L2 auf. Das zweite Batteriemodul 6 weist ferner einen positiven Pol 22 und einen negativen Pol 21 auf. Im Leerlauf liegt eine von der zweiten Spannungsquelle V2 gelieferte Spannung zwischen dem positiven Pol 22 und dem negativen Pol 21 an. The second battery module 6 thus has the second voltage source V2 and the second inductance L2. The second battery module 6 also has a positive pole 22 and a negative pole 21. When idling, a voltage supplied by the second voltage source V2 is applied between the positive pole 22 and the negative pole 21.
Der Ausgangskondensator CA weist ein positives Terminal 12 und ein negatives Terminal 11 auf. Bei dem Ausgangskondensator CA handelt es sich beispielsweise um einen Zwischenkreiskondensator, welcher elektrisch mit einem Bordnetz des Kraftfahrzeugs verbunden ist. Die Batteriemodule 5, 6 können weitere Kondensatoren aufweisen, welcher dann zusammen mit dem Zwischenkreiskondensator den Ausgangskondensator CA bilden. The output capacitor CA has a positive terminal 12 and a negative terminal 11. The output capacitor CA is, for example, an intermediate circuit capacitor which is electrically connected to an on-board network of the motor vehicle. The battery modules 5, 6 can have further capacitors, which together with the intermediate circuit capacitor then form the output capacitor CA.
Die erste Schalteinheit 50 und die zweite Schalteinheit 60 sind vorliegend identisch aufgebaut. Die Schalteinheiten 50, 60 weisen jeweils ein erstes Schaltelement 61, ein zweites Schaltelement 62 und ein drittes Schaltelement 63 auf. Die Schaltelemente 61, 62, 63 weisen jeweils drei Anschlüsse auf, wobei zwischen einem ersten Anschluss und einem zweiten Anschluss eine Schaltstrecke gebildet ist, welche mittels eines dritten Anschlusses ansteuerbar ist. Ferner weisen die Schalteinheiten 50, 60 jeweils einen internen Knotenpunkt 25 auf. The first switching unit 50 and the second switching unit 60 are constructed identically in the present case. The switching units 50, 60 each have a first switching element 61, a second switching element 62 and a third switching element 63. The switching elements 61, 62, 63 each have three connections, a switching path being formed between a first connection and a second connection, which can be controlled by means of a third connection. Furthermore, the switching units 50, 60 each have an internal node 25.
Das erste Schaltelement 61, das zweite Schaltelement 62 und das dritte Schaltelement 63 sind vorliegend als Feldeffekttransistoren ausgebildet. Die Schaltelemente 61, 62, 63 weisen jeweils einen SOURCE-Anschluss, einen DRAIN-Anschluss und einen GATE-Anschluss auf. Die Schaltelemente 61, 62,The first switching element 61, the second switching element 62 and the third switching element 63 are in the present case designed as field effect transistors. The switching elements 61, 62, 63 each have a SOURCE connection, a DRAIN connection and a GATE connection. The switching elements 61, 62,
63 sind derart verschaltet, dass jeweils der erste Anschluss der SOURCE- Anschluss, der zweite Anschluss der DRAIN-Anschluss und der dritte Anschluss der GATE-Anschluss ist. Bei den Schaltelemente 61, 62, 63 handelt es sich vorliegend um n-Kanal- MOSFETs vom Anreicherungstyp. Die Schaltelemente 61, 62, 63 weisen jeweils eine Schaltstrecke sowie eine parallel zu der Schaltstrecke geschaltete Inversdiode auf. Die Inversdiode, welche auch als Body-Diode bezeichnet wird, entsteht in jedem MOSFET aufgrund von dessen interner Struktur und ist kein explizites Bauteil. 63 are connected in such a way that the first connection is the SOURCE connection, the second connection is the DRAIN connection and the third connection is the GATE connection. The switching elements 61, 62, 63 are in the present case n-channel MOSFETs of the enhancement type. The switching elements 61, 62, 63 each have a switching path and an inverse diode connected in parallel to the switching path. The inverse diode, which is also referred to as a body diode, is created in every MOSFET due to its internal structure and is not an explicit component.
Der erste Anschluss des ersten Schaltelements 61 ist mit dem Knotenpunkt 25 verbunden. Ein zweiter Anschluss des ersten Schaltelements 61 ist mit dem positiven Pol 22 des zugeordneten Batteriemoduls 5, 6 verbunden. Ein erster Anschluss des zweiten Schaltelements 62 ist mit dem Knotenpunkt 25 verbunden. Ein zweiter Anschluss des zweiten Schaltelements 62 ist mit dem positiven Terminal 12 des Ausgangskondensators CA verbunden. Ein erster Anschluss des dritten Schaltelements 63 ist mit dem negativen Pol 21 des zugeordneten Batteriemoduls 5, 6 und mit dem negativen Terminal 11 des Ausgangskondensators CA verbunden. Ein zweiter Anschluss des dritten Schaltelements 63 ist mit dem Knotenpunkt 25 verbunden. The first connection of the first switching element 61 is connected to the node 25. A second connection of the first switching element 61 is connected to the positive pole 22 of the associated battery module 5, 6. A first connection of the second switching element 62 is connected to the node 25. A second terminal of the second switching element 62 is connected to the positive terminal 12 of the output capacitor CA. A first connection of the third switching element 63 is connected to the negative pole 21 of the associated battery module 5, 6 and to the negative terminal 11 of the output capacitor CA. A second connection of the third switching element 63 is connected to the node 25.
Figur 2 zeigt eine schematische Darstellung des Batteriesystems 10 während einer ersten Phase des Verfahrens. Während der ersten Phase sind in der ersten Schalteinheit 50 das erste Schaltelement 61 geschlossen, das zweite Schaltelement 62 geschlossen und das dritte Schaltelement 63 geöffnet. Während der ersten Phase sind in der zweiten Schalteinheit 60 das erste Schaltelement 61 geschlossen, das zweite Schaltelement 62 geschlossen und das dritte Schaltelement 63 geöffnet. FIG. 2 shows a schematic illustration of the battery system 10 during a first phase of the method. During the first phase, the first switching element 61 in the first switching unit 50 is closed, the second switching element 62 is closed and the third switching element 63 is opened. During the first phase, the first switching element 61 in the second switching unit 60 is closed, the second switching element 62 is closed and the third switching element 63 is opened.
Ein Strom I fließt während der ersten Phase durch die zweite Spannungsquelle V2, durch die zweite Induktivität L2, sowie durch das erste Schaltelement 61 und durch das zweite Schaltelement 62 der zweiten Schalteinheit 60. Der Strom I fließt während der ersten Phase ferner durch die erste Spannungsquelle VI, durch die erste Induktivität LI, sowie durch das erste Schaltelement 61 und durch das zweite Schaltelement 62 der ersten Schalteinheit 50. Dabei wird elektrische Energie von der ersten Spannungsquelle VI zu der ersten Induktivität LI und zu der zweiten Induktivität L2 übertragen. Dabei sinkt der Ladungszustand des ersten Batteriemoduls 5. Nach Ende der ersten Phase wird das zweite Schaltelement 62 der zweiten Schalteinheit 60 geöffnet und das dritte Schaltelement 63 der zweiten Schalteinheit 60 wird geschlossen. Es beginnt eine zweite Phase. Das erste Schaltelement 61 der zweiten Schalteinheit 60 bleibt dabei geschlossen. Das erste Schaltelement 61 und das zweite Schaltelement 62 der ersten Schalteinheit 50 bleiben geschlossen, und das dritte Schaltelement 63 der ersten Schalteinheit 50 bleibt geöffnet. A current I flows during the first phase through the second voltage source V2, through the second inductance L2, as well as through the first switching element 61 and through the second switching element 62 of the second switching unit 60. The current I also flows through the first voltage source during the first phase VI, through the first inductance LI, as well as through the first switching element 61 and through the second switching element 62 of the first switching unit 50. Electrical energy is transmitted from the first voltage source VI to the first inductance LI and to the second inductance L2. The state of charge of the first battery module 5 drops in the process. After the end of the first phase, the second switching element 62 of the second switching unit 60 is opened and the third switching element 63 of the second switching unit 60 is closed. A second phase begins. The first switching element 61 of the second switching unit 60 remains closed. The first switching element 61 and the second switching element 62 of the first switching unit 50 remain closed, and the third switching element 63 of the first switching unit 50 remains open.
Figur 3 zeigt eine schematische Darstellung des Batteriesystems 10 während der zweiten Phase des Verfahrens. Während der zweiten Phase sind in der ersten Schalteinheit 50 das erste Schaltelement 61 geschlossen, das zweite Schaltelement 62 geschlossen und das dritte Schaltelement 63 geöffnet. Während der zweiten Phase sind in der zweiten Schalteinheit 60 das erste Schaltelement 61 geschlossen, das zweite Schaltelement 62 geöffnet und das dritte Schaltelement 63 geschlossen. FIG. 3 shows a schematic representation of the battery system 10 during the second phase of the method. During the second phase, the first switching element 61 in the first switching unit 50 is closed, the second switching element 62 is closed and the third switching element 63 is opened. During the second phase, the first switching element 61 in the second switching unit 60 is closed, the second switching element 62 is opened and the third switching element 63 is closed.
Ein Strom I fließt während der zweiten Phase durch die zweite Spannungsquelle V2, durch die zweite Induktivität L2, sowie durch das erste Schaltelement 61 und durch das dritte Schaltelement 63 der zweiten Schalteinheit 60. Dabei wird elektrische Energie von der zweiten Induktivität L2 zu der zweiten Spannungsquelle V2 des zweiten Batteriemoduls 6 übertragen. Dabei steigt der Ladungszustand des zweiten Batteriemoduls 6. A current I flows during the second phase through the second voltage source V2, through the second inductance L2, as well as through the first switching element 61 and through the third switching element 63 of the second switching unit 60. Electrical energy is thereby transferred from the second inductance L2 to the second voltage source V2 of the second battery module 6 is transmitted. The state of charge of the second battery module 6 increases in the process.
Optional kann das dritte Schaltelement 63 der zweiten Schalteinheit 60 während der zweiten Phase auch geöffnet bleiben. Das dritte Schaltelement 63 ist, wie bereits erwähnt, als MOSFET ausgeführt und weist eine Inversdiode, die auch als Body-Diode bezeichnet wird, auf. Das dritte Schaltelement 63 ist derart in der zweiten Schalteinheit 60 angeordnet, dass der während der zweiten Phase fließende Strom I durch die besagte Inversdiode fließen kann. Optionally, the third switching element 63 of the second switching unit 60 can also remain open during the second phase. As already mentioned, the third switching element 63 is designed as a MOSFET and has an inverse diode, which is also referred to as a body diode. The third switching element 63 is arranged in the second switching unit 60 in such a way that the current I flowing during the second phase can flow through the said inverse diode.
Nach Ende der zweiten Phase wird das zweite Schaltelement 62 der zweiten Schalteinheit 60 geschlossen und das dritte Schaltelement 63 der zweiten Schalteinheit 60 wird geöffnet. Es beginnt eine weitere erste Phase. Das erste Schaltelement 61 der zweiten Schalteinheit 60 bleibt dabei geschlossen. Das erste Schaltelement 61 und das zweite Schaltelement 62 der ersten Schalteinheit 50 bleiben geschlossen, und das dritte Schaltelement 63 der ersten Schalteinheit 50 bleibt geöffnet. Die Erfindung ist nicht auf die hier beschriebenen Ausführungsbeispiele und die darin hervorgehobenen Aspekte beschränkt. Vielmehr ist innerhalb des durch die Ansprüche angegebenen Bereichs eine Vielzahl von Abwandlungen möglich, die im Rahmen fachmännischen Handelns liegen. After the end of the second phase, the second switching element 62 of the second switching unit 60 is closed and the third switching element 63 of the second switching unit 60 is opened. Another first phase begins. The first switching element 61 of the second switching unit 60 remains closed. The first switching element 61 and the second switching element 62 of the first switching unit 50 remain closed, and the third switching element 63 of the first switching unit 50 remains open. The invention is not restricted to the exemplary embodiments described here and the aspects emphasized therein. Rather, within the range specified by the claims, a large number of modifications are possible that are within the scope of expert knowledge.
Claims
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DE102019212351.1A DE102019212351A1 (en) | 2019-08-19 | 2019-08-19 | Battery system for a motor vehicle, method for operating a battery system and motor vehicle |
PCT/EP2020/071196 WO2021032411A1 (en) | 2019-08-19 | 2020-07-28 | Battery system for a motor vehicle for balancing battery modules, method for operating a battery system and motor vehicle |
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CN (1) | CN114270594A (en) |
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GB2376357B (en) * | 2001-06-09 | 2005-05-04 | 3D Instr Ltd | Power converter and method for power conversion |
JP4501893B2 (en) * | 2006-04-24 | 2010-07-14 | トヨタ自動車株式会社 | Power supply system and vehicle |
TWI351806B (en) * | 2008-05-29 | 2011-11-01 | Univ Yuan Ze | High step-up isolated converter with two input pow |
TWI397250B (en) * | 2009-04-28 | 2013-05-21 | Univ Southern Taiwan | Two way full bridge zero-voltage and zero-current switching dc-dc converter |
US8860348B2 (en) | 2010-09-02 | 2014-10-14 | GM Global Technology Operations LLC | Method and apparatus for controlling a high-voltage battery connection for hybrid powertrain system |
ITTO20110862A1 (en) | 2011-09-28 | 2013-03-29 | Magneti Marelli Spa | DISCHARGE PROCEDURE OF A DC-LINK CONDENSER IN A DC-DC CONVERTER EQUIPMENT AND ITS DC-DC CONVERTER EQUIPMENT |
CN104201888B (en) * | 2014-09-15 | 2016-05-11 | 盐城工学院 | A kind of current control method of symmetrical structure converter |
KR102305583B1 (en) * | 2014-10-23 | 2021-09-27 | 삼성전자주식회사 | Apparatus for charging and discharging battery |
US10177661B2 (en) * | 2015-06-15 | 2019-01-08 | Futurewei Technologies, Inc. | Control method for buck-boost power converters |
WO2017064820A1 (en) | 2015-10-13 | 2017-04-20 | Hitachi, Ltd. | Electric power generation system and its control system |
CN105610222B (en) * | 2016-03-01 | 2018-02-27 | 中南民族大学 | Battery unit low-voltage emergency supply circuit and emergency service method |
DE202017000735U1 (en) * | 2017-02-09 | 2018-05-11 | Varta Microbattery Gmbh | Electronic switching device of a battery management system and battery |
US11075598B2 (en) | 2017-08-15 | 2021-07-27 | Quanten Technologies, Inc. | Connection bars for motor system |
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WO2021032411A1 (en) | 2021-02-25 |
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