Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R16/00—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for
  • B60R16/02—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements
  • B60R16/03—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for supply of electrical power to vehicle subsystems or for
  • B60R16/033—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for supply of electrical power to vehicle subsystems or for characterised by the use of electrical cells or batteries
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
  • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
  • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
  • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
  • B60L58/19—Switching between serial connection and parallel connection of battery modules
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
  • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
  • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
  • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
  • B60L58/21—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules having the same nominal voltage
• • 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
  • H02J7/0024—Parallel/serial switching of connection of batteries to charge or load circuit
• • 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
  • H02J7/14—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
  • H02J7/1423—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle with multiple batteries
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
  • B60L2260/00—Operating Modes
  • B60L2260/20—Drive modes; Transition between modes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
  • B60L2260/00—Operating Modes
  • B60L2260/20—Drive modes; Transition between modes
  • B60L2260/22—Standstill, e.g. zero speed
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
  • B60L2260/00—Operating Modes
  • B60L2260/20—Drive modes; Transition between modes
  • B60L2260/26—Transition between different drive modes
• • 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
• • 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
  • H02J2310/46—The network being an on-board power network, i.e. within a vehicle for ICE-powered road vehicles
• • 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 vehicle electrical system and a method for operating a vehicle electrical system for a motor vehicle.
• a motor vehicle is specified with such a vehicle electrical system, and a battery management system and a computer program, which are set up to carry out the described method.
• an electrical system is provided for supplying the electric starter or starter for the internal combustion engine and other electrical devices of the motor vehicle, which is operated by default with 12 volts. When starting the engine is on the electrical system of a
• Starter battery provided a voltage to a starter, soften the
• Internal combustion engine starts when, for example, by a corresponding starter signal, a switch is closed. If the internal combustion engine is started, this drives an electric generator, which then generates a voltage of about 12 volts and provides it via the electrical system to the various electrical consumers in the vehicle. The electric generator also charges the starter battery charged by the starting process. If the battery is charged via the electrical system, the actual voltage may also be above the rated voltage, eg. B. at 14 V or at 14.4 V.
• the electrical system with 12 V, or 14 V voltage is referred to in the present disclosure as a low-voltage electrical system. It is known in electric and hybrid vehicles another electrical system with a
• a vehicle electrical system for a motor vehicle comprises a low-voltage sub-network for at least one low-voltage consumer and a high-voltage sub-network for at least one high-voltage consumer and a starter generator, the high-voltage subnet being connected to the low-voltage subnetwork via a coupling unit which is designed to take energy from the high-voltage subnet and the low-voltage subnet supply, wherein the high voltage subnet comprises a battery which is adapted to generate the high voltage and to the
• the invention has the advantage that can be operated by the low voltage subnet electrical consumers, which are designed for a low first voltage, and for high-power consumers, the high-voltage sub-network is ready, i. the
• Partial electrical system with the opposite voltage to the first voltage.
• the supply of the low voltage subnetwork is the loading and unloading in the
• the low voltage subnetwork supply via the high voltage subnetwork takes place unidirectionally, d. H.
• the coupling unit preferably provides the energy transfer only in one direction.
• the terms “battery” and “battery unit” are used in the present description, adapted to common usage, used for accumulator or Akkumulatorü.
• the battery includes one or more battery packs that include a battery cell
• Battery Module a module string or a battery pack can denote.
• Battery cells are preferably spatially combined and interconnected circuitry, for example, connected in series or parallel to modules.
• modules can form so-called battery direct converters (BDCs) and several battery direct converters form a battery direct inverter (BDI).
• BDCs battery direct converters
• BDI battery direct inverter
• the electrical system can be used both in stationary applications, e.g. in wind turbines, as well as in vehicles, e.g. in hybrid and electric vehicles.
• the electrical system can be used in vehicles that have start-stop systems.
• the presented system ie the electrical system and the battery management system is particularly suitable for use in vehicles having a 48 volt generator and a 14 volt starter, the 14 volt starter preferably for start / stop systems is designed.
• the presented system is particularly suitable for use in vehicles which have a so-called boost recuperation system (BRS).
• BRS boost recuperation system
• Boost recuperation systems generate electrical energy during braking, downhill or sail operation to supply the electrical consumers.
• the boost recuperation system increases the efficiency of the system so that fuel can be saved or emissions can be reduced.
• the battery in the high voltage subnetwork either supports the internal combustion engine, which is called a boost, or it is even used at low speeds for short distances even for purely electric driving, e.g. with an electric parking and Ausparken.
• the coupling unit has at least one reverse-blocking switch.
• the reverse blocking switches are preferably suitable for connecting and disconnecting a selectively connectable battery unit. These switches have the property that in the "on” state, they allow current to flow in only one direction and, in the "off” state, they can absorb a blocking voltage of either polarity.
• the low-voltage subnetwork has at least one capacitor.
• the capacitor is preferably adapted to the
• Lax is the maximum on-board electrical system current that is to flow during switching operations in the low-voltage sub-network
• t equals the length of time during which no battery unit is available for the supply
• AU max the maximum permissible change in the
• the electrical system is a low voltage subnet for at least one
• High voltage subnet is connected to the low voltage subnet via a coupling unit, which is adapted to take the high voltage subnet power and supply the low voltage subnet, the high voltage subnet having a battery which is adapted to generate the high voltage and to the
• Coupling unit is set to selectively connect the battery units to the low voltage subnet, it is provided that the one battery unit is connected to the low voltage subnet, which has the highest state of charge.
• the method according to the invention has the advantage that a state is established during operation in which the battery units have approximately the same state of charge.
• this ensures that the cells age evenly, i. for example, have a same internal resistance and / or a same capacity.
• the supply of the low voltage subnet changes from a battery unit to that battery unit which has a correspondingly higher state of charge than the battery unit currently used to supply the low voltage subnet.
• Low voltage sub-network is superimposed on the charging and discharging processes in the high voltage sub-network and the low-voltage sub-network power supply takes place unidirectionally ensured by the inventive method that always the battery unit is discharged faster with the highest state of charge or is charged slower than the other sub-batteries. This results in a symmetrization of the charge states of the sub-batteries result.
• Battery unit when exceeding a threshold value of a state of charge difference of the battery units. This ensures that at the same or similar state of charge of the battery units no fast, constant change from one battery unit to the next, followed by a return change, as soon as the unused
• Battery unit has the highest state of charge. Particularly preferred is the
• Threshold of the state of charge difference of the battery units a defined value between 0.5% and 20%, preferably between 1% and 5%, more preferably about 2%.
• the change of switched on takes place
• Circuit breaker are. Due to the operation of the reverse blocking switch would be connected to the higher potential of the two battery units during the switching phase with simultaneous operation of the switch, the positive pole of the low voltage subnet, and the negative pole of the electrical system with the lower potential of the two
• the advantageous switching concept also prevents a brief increase in the low voltage during switching operations in the coupling unit used.
• a buffer device which is designed, for example, as a capacitor in the low-voltage subnetwork, the voltage dip in the low-voltage subnetwork is further advantageously limited.
• the voltage dip in the low-voltage subnetwork can be further advantageously reduced if the switchover occurs at such times when the on-board electrical system current is as low as possible. This can be done, for example, by evaluating a signal for the on-board electrical system current and dependent control of the switch of the coupling unit. In addition, syncing with a
• Consumer management system to provide high-performance consumers, such.
• the invention also proposes a computer program according to which one of the methods described herein is performed when the computer program is executed on a programmable computer device.
• the computer program can be, for example, a module for implementing a device for operating an electrical system or a module for implementing a
• the computer program can be stored on a machine-readable storage medium, such as on a
• the computer program may be provided for download on a computing device, such as on a server or a cloud server, for example via a data network, such as the Internet, or a communication link, such as a telephone line or a wireless link.
• a battery management system (BMS) which has means for carrying out one of the described methods for operating one of the described electrical systems.
• BMS battery management system
• Battery management system a unit which is adapted to determine the state of charge of the battery units, and in particular the battery unit with the highest state of charge, and a unit which is arranged to control the coupling unit so that battery units are selectively connected to the low voltage subnet, in particular that with the highest charge level.
• the battery management system comprises a further unit, which is set up to exceed a threshold value of one
• the invention provides a low-cost vehicle electrical system with a lithium-ion battery system for vehicles, which is a high-voltage subnetwork with a 48-volt starter generator, a low-voltage subnetwork and a boost recuperation system with unidirectional
• the system is also characterized by its low volume, low weight and long life. Due to the multiple redundant designed
• the proposed method according to the invention comprises an operating strategy which enables the supply of the low voltage subnetwork and electrical energy
• the storage of electrical energy is optimized so that as much electrical energy can be recovered in a braking operation and the battery can be charged with the highest possible performance.
• FIG. 1 shows a low-voltage on-board network according to the prior art
• 2 shows a vehicle electrical system with a high-voltage sub-network and a low-voltage sub-network and a unidirectional, potential-separating DC / DC converter
• FIG. 3 shows a vehicle electrical system with a high-voltage sub-network and a low-voltage sub-network and a bidirectional, potential-separating DC / DC converter
• FIG. 4 shows a vehicle electrical system with a high-voltage sub-network and a low-voltage sub-network and a unidirectional, galvanically non-separating DC / DC converter
• FIG. 5 shows a coupling unit according to an embodiment of the invention
• FIG. 6 shows the coupling unit from FIG. 5 in an exemplary operating state
• FIG. 7 shows the coupling unit of FIG. 5 during an exemplary switching operation
• FIG. 1 shows a vehicle electrical system 1 according to the prior art.
• Internal combustion engine is provided via the electrical system 1 from a starter battery 10, a voltage to a starter 1 1 available, which (not shown) starts the engine when, for example, by a corresponding starter signal, a switch 12 is closed. If the internal combustion engine is started, this drives an electric generator 13, which then generates a voltage of about 12 volts and provides it via the vehicle electrical system 1 to the various electrical consumers 14 in the vehicle. The electric generator 13 also charges the starter battery 10 charged by the starting process.
• FIG. 2 shows a vehicle electrical system 1 with a high-voltage sub-network 20 and a
• the electrical system 1 may be a vehicle electrical system of a vehicle, in particular a motor vehicle, transport vehicle or forklift.
• the high-voltage sub-network 20 is, for example, a 48-volt electrical system with a
• the generator 23 which is not shown by an internal combustion engine is operable.
• the generator 23 is formed in this embodiment, in
• High voltage subnet 20 further includes a battery 24, which may be formed for example as a lithium-ion battery and which is adapted to output the necessary operating voltage to the high voltage subnet.
• a battery 24 which may be formed for example as a lithium-ion battery and which is adapted to output the necessary operating voltage to the high voltage subnet.
• load resistors 25 are arranged, which may be formed for example by at least one, preferably by a plurality of electrical consumers of the motor vehicle, which are operated with the high voltage.
• the low-voltage sub-network 21 which is arranged on the output side of the DC / DC converter 22, there are a starter 26, which is set to close a switch 27 to start the engine, and an energy storage 28, which is set, the low voltage in Height of for example 14 volts for that
• Low voltage subnet 21 to provide.
• the low-voltage sub-network 21 further consumers 29 are arranged, which are operated with the low voltage.
• the vehicle electrical system voltage in the low-voltage sub-network 21 is in driving operation, depending on the temperature and state of charge of the energy storage device 28, approximately in the range between 10.8 volts and 15 volts.
• the DC / DC converter 22 is connected on the input side to the high-voltage sub-network 20 and to the generator 23. The DC / DC converter 22 is the output side with the
• the DC / DC converter 22 is configured to receive a DC voltage received on the input side, for example a DC voltage with which the high voltage subnet is operated, for example between 12 and 48 volts inclusive, and to generate an output voltage which is different from the voltage received on the input side , in particular one
• FIG. 3 shows a vehicle electrical system 1 with a high-voltage sub-network 20 and a
• Low voltage sub-network 21 which are connected by a bidirectional, potential-separating DC / DC converter 31.
• the on-board electrical system 1 shown is designed essentially like the vehicle electrical system shown in FIG. 2, the generator being integrated in the high-voltage subnet 20 and for the energy transfer between the sub-board networks 20, 21 a DC / DC converter 31 is used, which is designed to be electrically isolated. Batteries 24, 28 and consumers 25, 29 are also arranged in both subnetworks 20, 21, as described with reference to FIG. Essentially, the system illustrated in FIG. 3 differs in the integration of the starter. While in the system shown in Figure 2, the starter 26 is disposed in the low voltage sub-network 21 and thereby the DC / DC converter 22 unidirectional for energy transport from
• High voltage sub-network 20 may be designed in the low voltage sub-network 21, in the architecture shown in Figure 3, a starter generator 30 is used in the high-voltage sub-network 20.
• the DC / DC converter 31 is bidirectional, so that the lithium-ion battery 24 can be charged via the low-voltage sub-network 21, if necessary. The jump start of the low-voltage vehicle is then via the
• FIG. 4 shows a vehicle electrical system 1 with a high-voltage sub-network 20 and a
• Low voltage subnet 21 for example, a vehicle electrical system 1 of a vehicle, in particular a motor vehicle, transport vehicle or forklift.
• the electrical system 1 is particularly suitable for use in vehicles with a 48-volt generator, a 14-volt starter and a boost recuperation system.
• the high-voltage sub-network 20 includes a starter-generator 30, which has a
• the starter-generator 30 is designed to generate electrical energy as a function of a rotational movement of the engine of the vehicle and to feed it into the high-voltage sub-network 20.
• a further starter may be provided for a first start in a start-stop operation of the vehicle in the low-voltage sub-network 21.
• load resistors 25 are arranged, which may be formed for example by at least one, preferably by a plurality of electrical consumers of the motor vehicle, which are operated with the high voltage.
• the high-voltage sub-network 20 also includes a battery 40, which may be formed, for example, as a lithium-ion battery and which is arranged, the
• the lithium-ion battery 40 preferably has a minimum capacity of approximately 15 Ah at a nominal voltage of 48 V in order to be able to store the required electrical energy.
• the battery 40 has a plurality of battery units 41 -1, 41 -2, ... 41 -n, wherein the
• Battery units 41 are assigned a plurality of battery cells, which are usually connected in series and partially in addition to each other in parallel to the required
• the individual battery cells are, for example, lithium-ion batteries with a voltage range of 2.8 to 4.2 volts.
• the battery units 41 -1, 41 -2, ... 41 -n are individual voltage taps 42-1, 42-2, ... 42-n + 1 assigned, via which the voltage of a coupling unit 33 is supplied.
• the Einzelpressivesabgriffe 42 are disposed between the battery units 41, and at the ends of the battery 40 each one. With a number of n battery units, this results in n + 1 Einzelschreibsabgriffe 42. Due to the additional Einzelpressivesabschreibe 42, the lithium-ion battery 40 is divided into a plurality of battery units 41 -1, 41 -2, ... 41 -n, which in the frame The invention may also be referred to as sub-batteries.
• the individual voltage taps 42 are selected such that the battery units 41 each have a voltage level with which the low voltage subnetwork 21, i. the 14-volt electrical system, can be supplied.
• the Einzelschreibsabgriffe 42 of the battery units 41 are, as shown in Figure 4, the coupling unit 33 is supplied.
• the coupling unit 33 has the task, at least one of the battery units 41 of the battery 40 to the
• Low-voltage subnet 21 to turn on its operation or support.
• the coupling unit 33 couples the high voltage subnet 20 to the
• Low-voltage sub-network 21 and provides the output side, the low-voltage sub-network 21, the necessary operating voltage ready, for example, 12 V or 14 V.
• the low-voltage sub-network 21 includes the low-voltage consumers 29, which are designed, for example, for operation at 14 V voltage.
• the lithium-ion battery 40 the supply of closed circuit loads, which are shown as a consumer 25, 29, takes over when the vehicle is parked.
• the requirements of the so-called airport tests are met, wherein after six weeks of service the vehicle is still bootable and the battery provides the quiescent currents of the low-voltage consumers 29 in the low-voltage subnet 21 during the service life, so that, for example, an anti-theft alarm system is supplied.
• a high-performance memory 28 or buffer memory is optionally arranged, which can deliver very high power for a short time, ie. H. optimized for high performance.
• the high-performance memory 28 fulfills the purpose that overvoltages when switching the battery units 41 are further avoided. Is used as
• High-performance memory 28 a capacitor used, so its sizing is preferred: ⁇ ⁇ ⁇ max ⁇ switch
• l max is the maximum on-board electrical system current that can flow during the switching operations in the electrical system
• t umschait the period during which no battery unit 41 is ready for the supply
• AU max the maximum permissible change of
• the electrical system shown in Figure 4 may further comprise a battery management system (BMS) (not shown).
• BMS battery management system
• the battery management system comprises a control unit which is set up to acquire and process measurement data on temperatures, voltages provided, discharged currents and charge states of the battery 40 or of the battery units 41, and from this statements about the
• the battery management system in this case comprises a unit which is set up to control the coupling unit 33 in such a way that it can switch on the battery units 41 selectively in the low-voltage sub-network 21.
• FIG. 5 shows a coupling unit 33, which is designed as a unidirectional, galvanically non-separating DC-DC converter (DC / DC converter).
• the coupling unit 33 comprises reverse blocking switches 44, 45, which have the property that they are in one Condition "on” allow a current flow only in one direction and in a second state “off” can receive a reverse voltage of both polarity.
• This is an essential difference to simple semiconductor switches, such as IGBT switches, since they can not absorb reverse voltage in the reverse direction due to their intrinsic diode.
• two different types of switches are shown in FIG. 5, namely RSSJ 45 and RSS_r 44, which do not differ in their production, but are merely installed with different polarity.
• An example of the more detailed structure of the reverse blocking switches 44, 45 will be described with reference to FIG.
• the individual taps 42 of the battery units 41 are each branched at branching points 43 and each one of the different
• reverse blocking switch RSSJ 45 are the output side of the coupling unit 33 connected to the positive pole 52
• the reverse blocking switch RSS_r 44 are the output side of the coupling unit 33 connected to the negative pole 51.
• FIG. 6 shows the supply of the low-voltage sub-network 21 by way of example from FIG.
• Branch point 43-i also connects to another one
• Battery unit 41 -2 would lead, but via the switch RSS_r 44-j. The same applies to the second branch point 43-j, which in turn leads to a blocking
• the voltage level of the high voltage subnet 20 based on the mass of
• Low voltage sub-network 21 depends on which of the battery units 41 switched on is. In none of the operating states, however, does any of the potentials have an amount that exceeds a voltage limit equal to the sum of the high voltage and the low voltage, that is, approximately 62 volts for a 48 volt mains and a 14 volt mains. However, negative potentials can occur with respect to the ground of the low voltage subnetwork.
• the operation of the starter-generator 30 is independent of the operation of the coupling unit 33 and the supply of the low voltage subnet. In the through-connected
• Battery unit 41 which supplies the low voltage subnet 21, results in a
• the low voltage sub-network power Overlay by the low voltage sub-network power and possibly fed by the starter-generator in the entire lithium-ion battery charging current (generator mode) or by the entire lithium-ion battery removed discharge current (motor operation). As long as the allowable limits of the battery cells, e.g. the maximum allowable discharge current of the cells are not exceeded, these processes can be considered independently. Thus, the low voltage subnet 21 is supplied safely, exactly one of the battery units 41 via the associated switches 44, 45 of the coupling device 33 is switched on. Due to the multiple redundant supply of the
• Low voltage sub-network 21 can be constructed with the architecture presented a system which has a very high availability of electrical energy in the
• Figure 7 shows a switching operation by means of the coupling unit 33 by way of example from the battery unit 41 -1 to the battery unit 41 -n.
• a first current path 71 leads through a first reverse blocking switch RSSJ 45-i, via first voltage taps 42-1, 42-2 associated with the first battery unit 41-1, and via a second reverse blocking switch RSS_r 44-i to the negative pole 51.
• the current path 72 leads via a second reverse blocking switch RSSJ 45-k, via voltage taps 42-n, 42-n + 1, which are assigned to the n-th battery unit 41 -n, and via a further reverse blocking Switch RSS_r 44-k to the negative pole 51.
• the reverse inhibit switches 45-i, 44-i are turned off and the other reverse-inhibitable switches 45-k, 44-k are turned on.
• the switching commands for the switches 45-i, 44-i, 45-k, 44-k get synchronized, so would due to the operation of the backward barrier switch the positive pole 52 of the Low voltage subnet connected during the switching phase of the circuit breaker with the higher potential of the two sub-batteries and the negative pole 51 during the switching phase with the lower potential of the two sub-batteries, ie in the example with the negative terminal of the battery unit 41 -n. This would create a much larger voltage to the low voltage subnetwork in the short term, as the specification of
• the switch is made so that the switches of the current current part of the battery, in the example shown, the battery unit 41 -1, are turned off first and after the switches of the current-carrying part battery no longer carry power, the switches of the sub-battery, which supply of the low voltage subnetwork, switched on.
• the described principle is also called "break-before-make".
• the maximum removable energy is limited by evenly charged cells by the cell with the lowest state of charge.
• the maximum allowable load performance is limited by the cell with the highest state of charge for evenly aged cells.
• the maximum deliverable energy is limited by evenly aged cells by the cell with the highest state of charge. Since the battery system in a boost recuperation system should be able to store as much energy as possible during a braking process, and at the same time should be able to support a boost process as well as possible, this can be the reason for this
• Battery unit 41 used to supply the low voltage subnetwork, which has the highest state of charge at a given time.
• the requirements for the selection of the switching states of the coupling unit 33 can be met with the following operating strategy:
• the supply of the low voltage subnet 21 always takes place from that sub-battery 41, which currently has the highest state of charge. Since the supply of the low voltage subnet to the charging and
• Selection rule ensures that the sub-battery 41 is discharged faster with the highest state of charge or is charged slower than the other battery units 41. This has a symmetrization of the charge states of the sub-batteries result.
• a threshold value for the difference ASOCumschait of the charge states is introduced, e.g. a difference ASOCumschait with a defined value between 0.5% and 20%, preferably between 1% and 5%, more preferably about 2%, which must be exceeded, so that the supply of
• Low voltage sub-network 21 of a battery unit 41 to that battery unit 41 changes, which has a correspondingly higher state of charge than the current to
• FIG. 8 shows a possible structure of reverse-blocking switches 44, 45.
• the forward direction is indicated by I.
• a reverse blocking switch RSS_r 44 comprises, for example, an IGBT, MOSFET or bipolar transistor 101 and a diode 103 connected in series therewith.
• FIG. 8 shows a MOSFET 101 which has an intrinsic diode 102 shown in FIG. The diode 103 connected in series with the MOSFET 101 is poled against the direction of the intrinsic diode 102 of the MOSFET 101.
• the reverse blocking switch RSS_r 44 passes the current in the forward direction I and blocks in the opposite direction.
• the reverse blocking switch RSSJ 45 corresponds to the RSS_r 44, is installed only with the reverse polarity, so that the pass and reverse directions are reversed.
• the switches RSSJ 45, RSS_r 44 are characterized in particular by a barely noticeable delay in the switching operations, d. H. allow a very short switching time. By means of a suitable drive circuit, the time delay between switching off and switching on the switches can be set very precisely.

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• 2014
  • 2014-01-27 DE DE102014201344.5A patent/DE102014201344A1/de active Pending
• 2015
  • 2015-01-23 WO PCT/EP2015/051334 patent/WO2015110570A1/de active Application Filing
  • 2015-01-23 CN CN201580005813.2A patent/CN105934867A/zh active Pending

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