DE102011106944A1 - Battery management system for power supply system with low voltage range and high voltage range - Google Patents

Abstract

A power supply system (1), in particular for an electric or hybrid drive of a motor vehicle, has the following components: an electrical energy storage device (2) which supplies a low voltage and which at least one energy storage cell (3) and / or at least one cell module (4) has at least two energy storage cells (3); an electrical load (5) which is operated with a high voltage; a voltage converter (6), in particular a DC-DC converter, which converts a low voltage into a high voltage and / or a high voltage into a low voltage; a control device (8) for controlling the electrical energy storage device (2). Furthermore, the power supply system (1) has a low-voltage region (9), in which the electrical energy storage device (2) is arranged, and a high-voltage region (10), in which the electrical load (5) is arranged. It is proposed to arrange the control device (8) essentially in the low-voltage region (9) of the power supply system (1). In a particularly preferred embodiment of the invention, the control device (8) is substantially integrated in the voltage converter (6).

Description

The present invention relates to a power supply system, in particular for an electric or hybrid drive of a motor vehicle, with a low voltage range and a high voltage range, an electrical energy storage device which provides a low voltage and is arranged in the low voltage range of the power supply system, and an electrical load, which operated with a high voltage is and is arranged in the high voltage range of the power supply system.

The invention will be described in relation to the use in a motor vehicle and the power supply system for the electric or hybrid drive of the motor vehicle. It should be noted, however, that a power supply system according to the invention can also be used for other applications independent of motor vehicles, in particular stationary applications.

Under a power supply system is in the context of the present invention, a system with a power source for generating electrical energy, components for transmitting and possibly transforming the electrical energy, an electrical load for converting the electrical energy into another form of energy such as mechanical or thermal energy and Means to control these processes and possibly understood with other components.

The power supply system has an electrical energy storage device which supplies a low voltage and an electrical consumer which is operated with a high voltage.

A low voltage in the sense of this patent application is understood to mean a voltage between 0 and 90 V, preferably between 30 and 60 V, more preferably between 40 and 50 V. For the purposes of this patent application, a high voltage is understood to mean a voltage above 90 V, preferably above 150 V, more preferably above 250 V.

It should be noted that these voltage range limits do not necessarily coincide with the voltage range limits for low and high voltage which are common in the field of electrical power engineering. However, there are in the field of electrical vehicle technology common voltage ranges for electrical energy storage devices, in particular batteries such as lithium-ion batteries, and electrical consumers such as electric motors for driving the vehicles.

The low voltage supplied by the electrical energy storage device is preferably a DC voltage. The voltage at which the electrical load is operated is preferably an alternating voltage.

An electrical energy storage device is understood as meaning a device for storing energy, which is emitted in the form of electrical energy. The electrical energy storage device may be energy storage device operating according to purely electrical principles, for example a capacitor, or an electrochemical energy storage device, for example a (non-rechargeable) primary battery or a (rechargeable) secondary battery, d. H. an accumulator.

The invention will be described in terms of rechargeable electrical energy storage devices, but may also be applied to non-rechargeable electrical energy storage devices.

The electrical energy storage device has at least one, preferably a plurality of energy storage cells. Under an energy storage cell, the smallest unit in which energy can be stored, understood within an electrical energy storage device. An energy storage cell has, for example, a arranged in a cell housing electrode assembly of a plurality of anodes, cathodes and intervening separators, wherein in an electrochemical energy storage device, the electrode assembly is impregnated with an example liquid or gel electrolyte, and dischargers for the discharge and / or charging current and other devices such as protective circuits or overheating protection devices.

Furthermore, an electrical energy storage device can have at least one cell module. A cell module is understood to be a structural unit within the electrical energy storage device which has at least two energy storage cells with an electrical connection which is not released during normal operation. Preferably, a cell module has a housing, in which the at least two electrically interconnected energy storage cells are housed, a common electrical lead outward, and possibly other devices such as control circuits, sensors, as well as cooling and / or Löscheinrichtungen. The cell modules within the electrical energy storage device are preferably interconnected in parallel.

The energy storage cells within a cell module can be interconnected in any arrangement, but preferably they are connected first in series and then in parallel. For example, initially between 2 and 14 energy storage cells are connected in series to a cell string in series and then four such cell strings in parallel. In a series circuit of, for example, twelve energy storage cells with a rated voltage of 4 V, a rated voltage of the cell strand - and thus the parallel circuit of four cell strands - a rated voltage of 48 V, ie a low voltage as used herein.

Such a low voltage is extremely desirable for the operation of an electric vehicle for safety reasons, since, for example, in the case of a defect in the contact of live parts for the vehicle occupants or even in a casualty caused rescue personnel there is no immediate danger.

On the other hand, it is to achieve sufficient vehicle performance and a high ride comfort, z. As with regard to the acceleration capacity, the maximum speed or the pulling power of the vehicle, it is desirable to operate the electric motor with a high voltage as used herein to always ensure the generation of the required or desired torque.

The power supply system therefore furthermore has a voltage converter, in particular a DC-DC converter, which converts a low voltage into a high voltage and / or a high voltage into a low voltage. The voltage converter converts the low voltage generated by the electrical energy storage device into the high voltage required by the electrical consumer.

In the power system, a power flow in the reverse direction, i. H. from the electrical load to the electrical energy storage device, be provided, preferably in order to realize a regenerative braking, so the regeneration of braking energy by a driven as a generator during braking electric motor. In this case, the voltage converter also converts the high voltage supplied by the electrical load into that of the required low voltage, with which the electrical energy storage device, if it is rechargeable, can then be charged.

If the high voltage required by the electrical load is an AC voltage, the power supply system further includes an inverter that converts the DC high voltage supplied by the voltage converter into the AC high voltage required by the electrical load.

If the power supply system has an inverter, another reason for using a high voltage is that correspondingly smaller currents must flow to achieve the required electrical power than at a low voltage. Since the costs for the power semiconductors in the inverter electronics increase faster with the current than for the voltage for which they are designed, there is a cost advantage for the converter when using a high voltage. For the same reason, when using a high voltage, the lines preferably made of copper can be designed within the power supply system with a smaller cross section and are thus easier and cheaper than when using a low voltage.

Finally, without a voltage converter for generating a high voltage by the electrical energy storage device, it would be necessary to connect a large number of energy storage cells in series. However, this is inefficient because, when connected in series through the generally slightly different capacitances of the individual energy storage cells, an overall capacity loss occurs.

A power supply system of the type described above, which has an electrical energy storage device, an electrical load and a voltage converter is, for example, from the patent application US 5,373,195 known.

Furthermore, the power supply system has a low voltage region and a high voltage region.

The low voltage range contains essentially all components of the power supply system that are operated exclusively with a low voltage. Consequently, all voltages prevailing in the low voltage range are low voltages.

The high voltage range contains essentially all components of the power supply system that are wholly or partially operated with a high voltage. The voltages prevailing in the high voltage range are therefore essentially high voltages. However, in the high voltage range, smaller voltages than high voltages may prevail, since this is not a safety problem, unlike the reverse case in the low voltage range.

The voltage converter in this case forms the interface between the low-voltage range and the high-voltage range and is contained in the low-voltage range and with the other parts in the high-voltage range with those of its parts which carry only low voltages.

Furthermore, the power supply system has a control device for controlling the electrical energy storage device, preferably a battery management system. Control devices of this type perform a variety of functions, preferably the monitoring and control of the discharge and possibly the charge of the connected electrical energy storage devices based on measured parameters of the electrical energy storage devices such as voltages, currents and temperatures and possibly the corrective intervention in said operations for safe and optimized operation of the motor vehicle. For this purpose, in addition to the electric energy storage device, the control device also communicates with a large number of other components of the motor vehicle inside and outside the power supply system, for example with the electrical load, the voltage converter and other components such as a motor control system, an external charger, an external power supply Diagnostic device or vehicle-mounted sensors, such as acceleration sensors for impact detection.

Such control devices for electrical energy storage devices are known for example from the patent applications DE 10 2008 009 970 and DE 10 2008 052 986 the applicant of the present patent application.

In the DE 10 2008 009 970 a control device for a particular rechargeable energy storage unit ("battery management system") is proposed, which has at least a first control device and at least a first memory unit and a second control device and a second memory unit, wherein the first control device adhering to a target value of at least one functional parameter of at least one galvanic cell monitored, wherein the target value of the function parameter is stored in the first memory unit. The first and second memory units are signal-connected and exchange data on the functional parameters of the galvanic cells and "vital signs" with each other. This patent application also describes the evaluation of time profiles of functional parameters of the galvanic cells and the prognosis of their future time courses, for example with the aim of determining the progressive aging of the energy storage unit.

The DE 10 2008 052 986 has the technical development of such a battery management system in the form of an integrated circuit to the object.

The object of the invention of the present patent application is to provide a power supply system of the type mentioned, which makes use of the structure of the power supply system and enables safe operation of the power supply system.

This object is achieved by a power supply system having the features of independent claim 1. The dependent subclaims indicate advantageous developments of the invention.

According to the invention, the control device is arranged substantially in the low-voltage region of the power supply system. Only individual components of the control device, such as control lines or sensors that connect to components in the high voltage range such as the electrical load, may not be located in the low voltage range. However, these are only those components which are not absolutely necessary for the operation of the control device. The controller may continue to perform most of its functions if any or all of these components are turned off.

The arrangement of the control device according to the invention substantially in the low-voltage range has the advantage that a clear functional subdivision of the power supply system into the low-voltage range and the high-voltage range is possible. In particular, the low voltage range is still functional if the high voltage range is switched off, for example, for safety reasons or is not available for other reasons.

In a particularly preferred embodiment of the invention, the control device is substantially integrated in the voltage converter.

The term "integration" may mean on the one hand that both devices are designed together as a single component, which can be installed in one operation in the vehicle and in the certain connection lines, for example for a communication bus or for the power supply of the two devices , only exist once. Preferably, the two devices are housed in a common housing.

However, the term "integration" can also mean further that both devices are designed in the form of a single integrated circuit, which also has certain connection lines only once and / or housed in a single housing.

In addition to the obvious advantages of a single compared to two separate components - such as smaller footprint, lower weight, lower manufacturing and assembly costs and lower energy consumption - the integration of the control device in the voltage converter results in a further synergy effect that certain electronic Components such as microcontroller or - processor, memory modules or power electronics components must be provided only once.

In addition, with integration of the control device in the voltage converter, the low voltage generated by the electrical energy storage device and the high voltage generated by the voltage converter, both of which are available within the voltage converter, directly within the integrated component and thus measured in a very simple manner.

In order to realize the functions of the control device, for example as a battery management system, essentially only sensors for the parameters of the electrical energy storage device, for example the cell voltages, currents or temperatures, are then required as further components. Such sensors and possibly a - preferably "non-intelligent" - part of the components of the power supply system required for processing the sensor measured values, for example signal amplifiers, analog / digital converters, coding or modulation circuits, are preferably in or on the energy storage cells and / or arranged the cell modules.

The arrangement of the control device just described allows a particularly simple construction of the power supply system.

In a preferred embodiment of the invention, the control device has a measuring device for measuring at least one functional parameter of at least one energy storage cell, an evaluation device for evaluating at least one functional parameter of the at least one energy storage cell and at least one memory unit in order to store this functional parameter or a variable derived from this functional parameter.

A measuring device is to be understood as meaning a device for detecting a functional parameter of an energy storage cell. These may be, for example, sensors for measuring electrical variables such as electrical voltage, electrical current, electrical charge, but also the temperature of the energy storage cell.

Functional parameters are to be understood as physical quantities which may be useful for the description of an energy storage cell. These are, for example, the electrical capacity of the energy storage cell, the measurable between the two poles of the energy storage cell voltage at idle or the load-dependent terminal voltage, the strength of a charge or discharge leading electrical current, the internal resistance of an energy storage cell, the already charged or available electrical charge Energy storage cell, leakage currents between the poles within an energy storage cell or the temperature of the cell. Depending on the type of electrical energy storage device and the requirements for their operation, other physical quantities may be of interest.

An evaluation device is a device for converting a function parameter from a physical to a mathematical value, for example by scaling, for computational processing, for example by linking with other measured function parameters or other variables with the aid of predetermined calculation rules or for other processing such as summarizing or sorting meant the determined sizes. The evaluation device also serves to make use of a measured functional parameter for further processing by the control device.

The memory unit is used to store measured function parameters or variables derived therefrom, such. B. associated integrated or differentiated values. Together with these values, a temporal assignment is also stored in order to later be able to retrace the processes in the energy storage cells. A memory unit is an example of an electronic, magnetic or optical writable device for volatile or non-volatile storage of data, such as a RAM, a flash ROM, an EEPROM, a hard disk or a recordable compact disc.

In a further preferred embodiment of the invention, the variable derived from the functional parameter is the aging and / or the remaining service life of the electrical energy storage device, a cell module or an energy storage cell. This is important as an energy storage cell as the age progresses, their behavior may change so that, for example, an unchanged charge may result in a reduced charge or a reduced available voltage of the energy storage cell.

In order to determine the aging of the energy storage cell, the energy storage cell's function parameters measured by the measuring device predetermine its future chronological progression through the evaluation device and thus also the future recordable electrical charge of the energy storage cell and / or its removable electrical charge and / or its achievable maximum electrical voltage determined. In this way, a statement about the further operation of the electrical energy storage device is possible. From a prediction of the aging of one or more energy storage cells, it is also possible to make a prediction for the remaining economic life of these energy storage cells, individual cell modules or the entire electrical energy storage device. In this way, a required maintenance or a replacement required can be signaled.

In a further preferred embodiment of the invention, when there is a deviation of at least one functional parameter of an energy storage cell from a target value, the control device initiates at least one measure for maintaining this target value and / or switches off the energy storage cell if the measure remains unsuccessful. Such measures are preferably used for safe operation of the electrical energy storage device and thus the entire power supply system.

The functional parameter may be, for example, the temperature of an energy storage cell which may not exceed a certain maximum temperature in order to avoid ignition or other damage to the electrical energy storage device. A measure for maintaining the target value can then be, for example, a reduction of the charge current currently drawn from the energy storage cell and / or an increased cooling of the energy storage cell and / or the automatic supply of a cooling or extinguishing agent. If the cell temperature can not be reduced by these measures below the predetermined maximum temperature, the overheated energy storage cell or a cell module or the entire electrical energy storage device is turned off. In the latter case, the control device preferably attempts to switch off as few energy storage cells and / or cell modules as possible in order to maintain the operation of the power supply system, possibly in a limited form.

Preferably, the user is informed about such a measure or shutdown and receives, if the available capacity of the electrical energy storage device has changed by the measure or by the shutdown, a message about this capacity change.

In a further preferred embodiment of the invention, the measuring and / or the evaluation and / or the storage of at least one functional parameter or a variable of the at least one energy storage cell derived from this functional parameter occurs when the high-voltage region is substantially free of voltage.

Such a voltage-free state of the high-voltage region may be present, for example, when the entire power supply system has not yet been put into operation, for example, after installation of the power supply system or parts thereof as a unit, but before installation in the motor vehicle, or after removal from the vehicle and before dismantling and / or scrapping the power supply system.

Already in this state, which can last for a long time and in which, for example, the transport or storage of the power supply system or parts thereof, in particular the electrical energy storage device takes place, it is important to monitor the state of the electrical energy storage device and document.

Events in the electrical energy storage device that are of interest in this state and are to be detected, for example, short circuits, the dissociation of contacts (for example, by vibrations during transport), the development of dangerous heat or the unwanted discharge due to moisture-induced leakage currents. In general, this monitoring serves the safety as well as the value retention of the electrical energy storage device preferably during transport and storage. The possibility of such monitoring may even be required by law.

However, a voltage-free state of the high-voltage region can also be present after the motor vehicle has been put into operation, if this is not being used or if the high voltage in the high-voltage region has been switched off for another reason, for example after the detection of an impact.

In a further preferred embodiment of the invention, the control device determines whether an energy storage cell or a cell module is suitable for the power supply system and / or in which state an energy storage cell or a cell module is located.

Such a suitability test for an energy storage cell or a cell module can preferably be carried out during the initial equipping of the electrical energy storage device with energy storage cells or cell modules, but also if one or more energy storage cells or cell modules which are, for example, defective or over-aged have been replaced ,

The suitability test can relate, for example, to the type, the available voltage or the deliverable current of the energy storage cell. The suitability test can use the corresponding measured functional parameters of the energy storage cell or of the cell module. However, it is also possible to carry out the suitability test by reading out data via a communication connection between the control device and preferably a cell module. In this way, further relevant for the suitability of the energy storage cell or the cell module parameters can be determined, such as the manufacturer, an identification number or such function parameters that can not be measured directly physically, but are stored in data form in the energy storage cell or in the cell module For example, the highest or lowest allowable operating temperature or the maximum discharge current.

The result of such a suitability test can consist in the acceptance of the tested energy storage cell or the tested cell module and its / its electrical and / or data technology integration in the electrical energy storage device. The result can also consist in the rejection of the energy storage cell or cell module with output of appropriate information to the user or the maintenance personnel.

Accordingly, an initial check of the state of the energy storage cell or the cell module, for example, a determination of the state of charge, take place.

The result of such a condition test can consist in an automatic recharging of the new energy storage cell or the new cell module to a certain state of charge or cooling or heating to a certain operating temperature.

Both the suitability and the state test of a new stored in the electrical energy storage device energy storage cell or a cell module are used for the correct configuration and safe operation of the electrical energy storage device.

According to a further preferred embodiment of the invention, the measuring and / or the evaluation and / or the storage of at least one functional parameter or a variable of the at least one energy storage cell derived from this functional parameter takes place when the high-voltage region is under high voltage.

This condition of the power system is generally given during the proper and undisturbed operation of the power system. In this state, the control device also fulfills its main task, namely the control of the electrical energy storage device during operation of the motor vehicle in an optimally optimal, d. H. energy-saving and / or the electrical energy storage device gentle manner. In the optimization of the operation, for example, the aging of individual energy storage cells and their charging behavior within the cell module contained or within the entire electrical energy storage device can be taken into account in order to increase the usefulness of the electrical energy storage device and extend their life.

• – die Steuerungseinrichtung die elektrische Verbindung zwischen wenigstens zwei Energiespeicherzellen oder Zellmodulen unterbricht und/oder
• – die Auswertung des wenigstens einen Funktionsparameters der wenigstens einen Energiespeicherzelle den Schritt der Beurteilung der Funktionsfähigkeit der Energiespeicherzelle, eines Zellmoduls oder der elektrischen Energiespeichereinrichtung aufweist und/oder
• – eine von dem wenigstens einen Funktionsparameter der wenigstens einen Energiespeicherzelle abgeleitete Größe ein Bericht über die Funktionsfähigkeit der Energiespeicherzelle, eines Zellmoduls oder der elektrischen Energiespeichereinrichtung ist.

A further preferred embodiment of the invention is characterized in that, in the case of an abnormal operating condition, in particular in an accident,

• - The control device interrupts the electrical connection between at least two energy storage cells or cell modules and / or
• - The evaluation of the at least one functional parameter of the at least one energy storage cell comprises the step of assessing the operability of the energy storage cell, a cell module or the electrical energy storage device and / or
• A variable derived from the at least one functional parameter of the at least one energy storage cell is a report of the functional capability of the energy storage cell, of a cell module or of the electrical energy storage device.

The features mentioned correspond to an "accident safety mode" in which by singling the energy storage cells or cell modules an uncontrolled, sudden discharge of the energy storage cells by targeted interruption of electrical connections within the electrical energy storage device to be avoided.

At the same time - as far as this is automatically possible - the energy storage cells are to be checked for possible damage from the accident, preferably by a test program for the energy storage cells is started.

Finally, the user of the motor vehicle after the accident should receive a report with a reliable statement about the further functioning of the individual energy storage cells, the cell modules or the entire electrical energy storage device. This report should enable him to decide whether the vehicle can continue to be used - for example in emergency mode - or whether he needs external assistance. The report on the operability of the energy storage system is then immediately available to a called service employee and can assist him in its diagnosis and repair activity.

In a further preferred embodiment of the invention, the energy storage cells are rechargeable, and the control device can compensate for different states of charge of different energy storage cells by shifting charges between these energy storage cells.

As a result, the removal or storage of electrical charge, in particular in the case of a large number of energy storage cells connected in series, can be distributed more uniformly to the individual energy storage cells. This approach can increase the usable total capacity of the cell modules and the electrical energy storage device and extend the life of the individual energy storage cells and thus the entire electrical energy storage device. For such a charge balance both so-called static and so-called dynamic methods are known.

In a further preferred embodiment of the invention, the control device can control energy storage cells or cell modules with different designs and / or with different capacities and / or with different performance data.

This allows a more flexible configuration of the energy storage system by, for example, ionic and non-ionic energy storage cells such as lithium-ion batteries, lithium-polymer batteries, lithium-iron phosphate batteries and lead batteries, high-performance and high-energy batteries or even electric and electrochemical energy storage cells such as capacitors and accumulators can be mixed and operated together within an energy storage system. Accordingly, energy storage cells of different capacities can be mixed and their capacities accumulated. Preferably, the electrical energy storage device can thus be gradually "upgraded" over time, when new types of batteries with greater capacity are available.

In a further preferred embodiment of the invention, the control device, depending on the state of the power supply system, in particular of use and / or danger states, change the voltage in high voltage range, in particular turn on or off.

Such a dangerous condition is preferably in the detection of an impact of the motor vehicle, after which the high voltage in the vehicle should be switched off immediately, as exposed by the impact live parts that can bring the vehicle occupants or even third parties in mortal danger.

A condition of use in which the high voltage in the high voltage range is to be switched on or off is preferably the operation or non-operation of the vehicle, for example, but also the opening or closing of a battery door or bonnet, thereby revealing components that either even a high voltage lead (for example, the electric motor) or can affect such components (for example, by touching parts of the electrical energy storage device). This feature also serves the safe operation of the power supply device.

In a further preferred embodiment of the invention, the control device can acquire data on the power flow between the high-voltage region and the low-voltage region, preferably in both directions. The prerequisite for the detection of the power flow in both directions is that the voltage converter works bidirectionally, ie can convert both a low voltage into a high voltage and a high voltage into a low voltage.

During normal operation of the motor vehicle, a power flow takes place from the electrical energy storage device in the low voltage range to the electrical load in the high voltage range, a reverse power flow from the high voltage to the low voltage range, preferably in regenerative braking, take place when the electric motor of Motor vehicle is operated as a generator and the energy generated by this is fed back into the electrical energy storage device.

Another case for a power flow from the high voltage to the low voltage range may occur during charging of the electrical energy storage device, in particular in an external charging, which preferably takes place via a conventional 230 V mains connection, or in an internal charging, which preferably via a so-called "Range Extender" takes place, so a smaller internal combustion engine with electric generator, with the aim of increasing the range of the vehicle. In these cases, the already existing voltage converter can be used to generate the required low voltage.

Finally, the electrical energy storage device can also be used as an external energy buffer for a power grid, wherein the power flow during charging takes place as before and results in the return of the buffered energy into the power grid, a power flow from the low voltage to high voltage range.

In all cases mentioned, the control device can measure, evaluate and store data about the transmitted electrical power and energy in order to always keep up-to-date information about the state, for example the state of charge, of the electrical energy storage device, possibly also for the purpose of billing related and / or delivered Energy to derive from it.

In a further embodiment of the invention, the control device can monitor each cell module separately, wherein the at least two cell modules within the electrical energy storage device are preferably connected in parallel with each other. This also makes it possible to increase the service life of the cell modules and the energy storage cells contained therein. Monitored parameters or detected events are, for example, the voltages, currents, temperatures or charge states of the cell modules as well as over and under voltages, overcurrents, excess temperatures, short circuits or connection interruptions on the cell modules.

In a further embodiment of the invention, the control device can load individual energy storage cells or cell modules at least partially individually. In this way, the possibly different states of charge or capacities of individual energy storage cells, which are caused, for example, by different aging of the energy storage cells, can be taken into account. Similar to the charge equalization between individual energy storage cells described above, thereby a more uniform charge and discharge of the individual energy storage cells is possible, which in turn increases their life and the efficiency of the entire electrical energy storage device.

In a further embodiment of the invention, a plurality of electrical energy storage devices which supply different low voltages are arranged in the low voltage range. The various low voltages can result from different Verschaltungsarten the individual energy storage cells and / or from the use of energy storage cells of different types. By using different low voltages, the power supply system can, for example, be adapted particularly well to different operating conditions or operating conditions of a vehicle.

Preferably, electrical energy storage devices are used with different low voltages, which have different voltage levels. In this case, a voltage situation is understood to mean how quickly the voltage generated by the electrical energy storage device drops as the energy storage device discharges.

In this way, for example by the use of an electrical energy storage device with a good voltage position, a "reserve" can be maintained that still provides a sufficiently high low voltage even with progressive total discharge of the electrical energy storage devices. The remaining electrical energy storage devices can then be designed with a less good voltage position, whereby they are, for example, cheaper or have other technical advantages such as a larger maximum discharge current.

For the safety reasons mentioned above, the different low voltages used are preferably always at most 64 V DC.

Of course, several of the above-described embodiments of the invention - as far as this is technically possible - can be combined with each other.

Exemplary embodiments of the power supply system according to the invention are shown in the form of block diagrams in the following drawings. Show it:

1 a block diagram of a power supply system according to the invention and

2 a block diagram of a power supply system according to the invention, in which the control device is integrated in the voltage converter.

1 shows an embodiment of a power supply system according to the invention 1 for use in an electric or hybrid vehicle, the two surrounding blocks delimited by dashed lines forming the low voltage area 9 or the high voltage range 10 represent.

Within the low voltage range 9 There is a battery 2 , a battery management system 8th as well as that part of the voltage converter 6 in which only low voltages prevail. Hereby put the battery 2 the electrical energy storage device and the battery management system 8th the control device. The voltage converter 6 is a DC-DC converter. The battery 2 can be one or more cell modules 4 have, one of which is indicated by a finely dashed boundary line indicated. The cell module 4 in turn has two parallel strands of eight battery cells connected in series 3 on.

In the exemplary embodiment, the individual battery cells 3 each have a rated voltage of 4 V, so that each cell strand and thus also the entire cell module has a nominal voltage of 32 V. The battery cells 3 For example, lithium-ion cells with a maximum storage capacity of 60 Ah each.

Also in the low voltage range 9 is the battery management system 8th for controlling the battery 2 , The battery management system 8th performs all or part of the functions described above, including the regulation of the charging process for the battery 2 ,

In an exemplary configuration, the battery 2 with a charging rate of 1-3 C / s, a maximum of 5 C / s and a short time (for a maximum of 3 s) with 90 C / s. The discharge of the battery 2 which also comes from the battery management system 8th is controlled by default, with 1 to 10 C / s, with a maximum of 20 C / s and a short time (for 3 to 4 seconds) with 125 C / s. The last-mentioned peak discharge rate serves to provide a large drive power required for a short time, in particular during overtaking operations, whereby the peak discharge rate can be achieved very rapidly, for example with a maximum triggering time of 40 ms. The minimum operating temperature of the battery 2 is -40 ° C. Further exemplary data of the battery management system 8th 6 mW, the possibility of external monitoring and diagnostics via an I ² C or CAN bus, an RS-232 or a USB port. The battery management system 8th meets the test standard IEC 62660 as well as other ISO standards and standards for electromagnetic compatibility.

The battery management system 8th can be realized as a circuit on a printed circuit board, for example with the dimensions 250 × 80 mm, 180 × 200 mm or 200 × 300 mm and with a maximum height of 28 mm, or can also be designed as a single integrated circuit.

The functional connections between the components of the power supply system 1 are in 1 indicated by double arrows, which may stand for communication and / or power lines. In the case of communication lines, the connection, as already mentioned, for example, be made via a CAN bus or via a serial RS-232 interface.

In the low voltage area 9 is the battery 2 with the low voltage input of the voltage converter 6 connected. The battery management system 8th is with the battery 2 as well as the part of the voltage transformer 6 connected in the low voltage range, for example, to a malfunction or failure of the voltage converter 6 detect and then the battery 2 to shut down in an emergency.

In the high voltage range 10 is that part of the voltage converter 6 in which also high voltages prevail. Because the battery 2 provides a DC voltage and also the voltage converter 6 is a DC-DC converter, is the high voltage output of the voltage converter 6 with a converter 7 connected to the voltage transformer 6 supplied DC high voltage into an AC high voltage. The conversion in the inverter 7 is done with the help of power semiconductors.

Also with the inverter 7 is the battery management system 8th in connection; However, this connection is not permanent because, for example, in an emergency, the high voltage range 10 from the low voltage area 9 can be separated, whereby the said compound is separated. This connection is therefore marked by a dashed arrow.

Furthermore, it is located in the high voltage area 10 an electric motor 5 as an electrical consumer. The electric motor 5 may drive the mechanical drive system of the motor vehicle (not shown), consisting for example of a drive shaft, a clutch, a manual transmission, a differential gear and one or more driven wheels. It is also possible that the electric motor 5 is designed as a hub motor and directly drives a drive wheel. In this case, multiple electric motors 5 , For each driven wheel one, be provided, wherein the electric motors 5 individually to generate a torque required for the respective wheel are controllable. Furthermore, the electric motor 5 also be part of a hybrid drive with an additional internal combustion engine (not shown).

Also the electric motor 5 stands with the battery management system 8th For example, to detect an abnormal operating condition, such as overheating, and a subsequent emergency shutdown of the battery 2 , in connection. This connection is marked as dashed arrow for the same reasons as above. The connections between the battery management system 8th on the one hand and the inverter on the other 7 or the electric motor 5 On the other hand, only communication, but no power lines, as an energy transfer between the battery management system 8th in the low voltage range 9 and the inverter 7 or the electric motor 5 in the high voltage range 10 without another voltage converter would not be readily possible.

The power supply system according to the invention 1 can also have more, in 1 not shown components include, for example, a motor controller for specifying a required torque, a charger for the battery 2 with provision of an external charging connection or various sensors for measuring the battery or other parameters such as the battery voltage, the battery current, the battery temperature or the acceleration of the battery 2 is exposed.

Also, the electric motor 5 be used as a generator, in particular for the recovery of braking energy. The power flow then runs in 1 from right to left, ie from the electric motor 5 generated high voltage is in the inverter 7 , which in this case acts as a rectifier, or in an additionally provided rectifier converted into a DC high voltage, which from the voltage converter 6 is converted into a DC low voltage, with which finally the battery 2 is loaded.

All these functions can be performed by the battery management system 8th be controlled or monitored.

2 shows a further embodiment of a power supply system according to the invention 1 in which the battery management system 8th in the voltage converter 6 is integrated. The integration can be done as an additional circuit board or additional integrated circuit within the voltage converter 6 be executed or as an integrated circuit, which both the battery management system 8th as well as the voltage converter 6 contains. In the 2 illustrated embodiment of the invention is characterized by its minimal effort in addition to the control device 8th to be provided hardware.

Ideally, the functions of the battery management system 8th completely in one in the voltage converter 6 anyway provided microprocessor implemented. In this case, to realize the battery management system 8th only the required sensors for the battery and other parameters required.

Due to the integration of the battery management system 8th in the voltage converter 6 The connecting cables from the battery management system are also eliminated 8th to the voltage converter 6 , to the battery 2 as well as to the inverter 7 , as there are internal lines in the voltage converter 6 or the already existing connection lines between the voltage converter 6 and the battery 2 or the inverter 7 can be used. In this way, also results in a lower cabling overhead within the power supply system 1 , Only a connecting line to the electric motor 5 , which with the voltage transformer 6 is not immediately adjacent, is still provided.

LIST OF REFERENCE NUMBERS

1

Power system

2

battery

3

battery cell

4

cell module

5

electric motor

6

DC converter

7

inverter

8th

Battery Management System

9

The low voltage range

10

High voltage range

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5,373,195 [0020]
• DE 102008009970 [0026, 0027]
• DE 102008052986 [0026, 0028]

Cited non-patent literature

• IEC 62660 [0094]

Claims (15)

Power supply system ( 1 ), in particular for an electric or hybrid drive of a motor vehicle, wherein the power supply system ( 1 ): - an electrical energy storage device ( 2 ), which supplies a low voltage and which at least one energy storage cell ( 3 ) and / or at least one cell module ( 4 ) from at least two energy storage cells ( 3 ) having; - an electrical consumer ( 5 ), which is operated with a high voltage; - a voltage converter ( 6 ), in particular a DC-DC converter, which converts a low voltage into a high voltage and / or a high voltage into a low voltage; - a low voltage area ( 9 ), in which the electrical energy storage device ( 2 ) is arranged; - a high voltage area ( 10 ), in which the electrical consumer ( 5 ) is arranged; A control device ( 8th ) for controlling the electrical energy storage device ( 2 ); characterized in that the control device ( 8th ) essentially in the low voltage range ( 9 ) is arranged. Power supply system ( 1 ) according to claim 1, characterized in that the control device ( 8th ) substantially in the voltage converter ( 6 ) is integrated. Power supply system ( 1 ) according to one of the preceding claims, characterized in that the control device ( 8th ) a measuring device for measuring at least one functional parameter of at least one energy storage cell ( 3 ) and an evaluation device for evaluating at least one functional parameter of the at least one energy storage cell ( 3 ) and at least one memory unit in order to store this function parameter or a variable derived from this function parameter. Power supply system ( 1 ) according to claim 3, characterized in that the variable derived from the functional parameter evaluates the aging and / or the remaining lifetime of the electrical energy storage device ( 2 ), a cell module ( 4 ) or an energy storage cell ( 3 ). Power supply system ( 1 ) according to one of claims 3 or 4, characterized in that the control device ( 8th ) in case of deviation of at least one functional parameter of an energy storage cell ( 3 ) initiates at least one measure of compliance with this target value from a target value and / or, if this measure is unsuccessful, this energy storage cell ( 3 ) turns off. Power supply system ( 1 ) according to any one of claims 3 to 5, characterized in that the measuring and / or the evaluation and / or the storage of at least one function parameter or derived from this function parameter size of the at least one energy storage cell ( 3 ) occurs when the high voltage region ( 10 ) is substantially stress-free. Power supply system ( 1 ) according to claim 6, characterized in that the control device ( 8th ) determines whether an energy storage cell ( 3 ) or a cell module ( 4 ) for the power supply system ( 1 ) and / or in which state an energy storage cell ( 3 ) or a cell module ( 4 ) is located. Power supply system ( 1 ) according to claim 3 to 5, characterized in that the measuring and / or the evaluation and / or the storage of at least one functional parameter or of this function parameter derived size of the at least one energy storage cell ( 3 ) occurs when the high voltage region ( 10 ) is under high voltage. Power supply system ( 1 ) according to claim 8, characterized in that in an abnormal operating condition, in particular in an accident, - the control device ( 8th ) the electrical connection between at least two energy storage cells ( 3 ) or cell modules ( 4 ) and / or - the evaluation of the at least one functional parameter of the at least one energy storage cell ( 3 ) the step of assessing the operability of the energy storage cell ( 3 ), a cell module ( 4 ) or the electrical energy storage device ( 2 ) and / or - one of the at least one functional parameter of the at least one energy storage cell ( 3 ) derived a report on the functionality of the energy storage cell ( 3 ), a cell module ( 4 ) or the electrical energy storage device ( 2 ). Power supply system ( 1 ) according to one of the preceding claims, characterized in that the energy storage cells ( 3 ) and the control device ( 8th ) different states of charge of different energy storage cells ( 3 ) by shifting charges between these energy storage cells ( 3 ) can compensate. Power supply system ( 1 ) according to one of the preceding claims, characterized in that the control device ( 8th ) Energy storage cells ( 3 ) or cell modules ( 4 ) With can control different types and / or with different capacities and / or with different performance data. Power supply system ( 1 ) according to one of the preceding claims, characterized in that the control device ( 8th ) depending on the state of the power supply system ( 1 ), in particular of conditions of use and / or danger, the voltage in the high-voltage range ( 10 ), in particular on or off, can. Power supply system ( 1 ) according to one of the preceding claims, characterized in that the control device ( 8th ) Data on the power flow between the high-voltage area ( 10 ) and the low voltage area ( 9 ), preferably in both directions. Power supply system ( 1 ) according to one of the preceding claims, characterized in that the power supply system ( 1 ) a plurality of electrical energy storage devices ( 2 ), wherein the plurality of electrical energy storage devices ( 2 ) supply different low voltages, in each case at least one energy storage cell ( 3 ) and / or at least one cell module ( 4 ) from at least two energy storage cells ( 3 ) and in the low voltage range ( 9 ) are arranged, and wherein the control device ( 8th ) for controlling the plurality of electrical energy storage devices ( 2 ) serves. Method for controlling a power supply system ( 1 ), characterized in that the power supply system ( 1 ) is a power supply system according to one of the preceding claims and that the method for execution on the control device ( 8th ) of the power supply system ( 1 ) is provided.

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