DE102013212965A1 - Battery charge equalization device, battery management system and charge balance method - Google Patents

Abstract

A central battery charge balance device for charge equalization of a battery having a plurality of memory cells (4a, ..., 4f; 22a, ..., 22n; 32a, ..., 32n; 42a, ..., 42n) has: - at least one central one Energy storage (6, 23, 33, 43, 51) for storing and dispensing electrical energy; - a plurality of cell controllers (2a, ..., 2n; 21a; ..., 21n; 31a, ..., 31n; 41a, ..., 41n), each connected to the central energy store (6, 23, 33, 43, 51) are electrically coupled, each cell controller (2a, ..., 2n; 22a; ..., 22n; 32a, ..., 32n; 42a, ..., 42n) comprising at least one switch (5a, ...; ..., 5g) for driving at least one memory cell (4a, ..., 4f; 22a, ..., 22n; 32a, ..., 32n; 42a, ..., 42n) of the battery to the Memory cells (4a, ..., 4f; 22a, ..., 22n; 32a, ..., 32n; 42a, ..., 42n) electrical energy from the central energy store (6, 23, 33, 43, 51 ) and electrical energy from the memory cells (4a, ..., 4f; 22a, ..., 22n; 32a, ..., 32n; 42a, ..., 42n) to the central energy store (6, 23, 33, 43, 51) dissipate.

Description

The present invention relates to a central battery charge balance device, a battery management system having a central battery charge balance device, and a method for central charge balance of memory cells of a battery.

Basically, there is a growing demand for storage systems for electrical energy, also called electrical energy storage systems. Electrical energy storage systems find use in various technical fields, such as e.g. Wind turbines, emergency power systems and the like, but also in motor vehicles. As motor vehicles in particular electric vehicles and hybrid vehicles are known which use electrical energy storage systems.

These applications mentioned above place high demands on the reliability and reliability of electrical energy storage systems. For example, a complete failure of an electrical energy storage system may compromise the performance of a motor vehicle, such as a car. the ability to drive an electric or hybrid vehicle.

Electric energy storage systems typically have a battery that is composed of a plurality of memory cells connected in series. To further increase the capacity, memory cells connected in series can also be connected in parallel with one another. Due to the series connection of the memory cells, a malfunction of a single memory cell typically also affects the other memory cells in series, since the output current of the battery must flow through all of the memory cells arranged in the series circuit, also through the faulty memory cell. Has e.g. the faulty memory cell an against infinite resistance, so the output current of the series connection of memory cells with the faulty memory cell drops sharply or in extreme cases even approaches zero.

For monitoring of memory cells of a battery, the use of a so-called battery management system has proven particularly useful in the automotive sector. This determines a state of charge (SOOC), state of health (SOH), state of function (SOF), or the like for each individual memory cell from parameters such as memory cell voltage, memory cell current, and memory cell temperature ,

In particular, due to production differences between individual memory cells and different load states of individual memory cells, memory cells typically have different charge states after a certain lifetime, which are caused by differences in the capacitance and in the internal resistance. The aging of the individual memory cells can increase differences in the charge states.

To compensate for differences in the charge states of the memory cells, so-called cell charge state balancers, also called "balancers" or "cell balancers" are known, which are implemented as balancing circuits. If these charge states were not compensated, individual memory cells could be used, for example, due to the different capacitances and internal resistances of the memory cells. can be overcharged, which in turn can lead to a shorter life and also to performance or availability losses of the battery.

Like the German disclosure DE 10 2010 039 913 A1 discloses two basic types of memory cell balancing. A first basic type is so-called resistive balancing, in which each memory cell is coupled to a resistor and in which excess electrical energy is converted into heat via this resistor. Such balancers are also referred to as "passive balancers". As a second basic type balancers are known in which electrical energy storage, such as coils or capacitors, are provided to buffer electrical energy and to transfer from one memory cell to another.

In the following, examples of the prior art for the different types of balancing and battery management systems are shown.

From the international patent application WO 2011/078478 A2 For example, a battery management system with cell balancing for a high-voltage battery is known. Several cells of the high-voltage battery are each combined in one package. Each package is assigned its own subordinate battery management module. A main battery management module controls the subordinate battery management modules, receives cell voltage and cell temperature information, and provides the subordinate battery management modules with balance information.

The international patent application WO 2012/119297 A1 discloses a battery management system for a battery having multiple battery packs, each battery pack having a balancer Has. Each balancer of the associated battery pack may have a resistance, capacitance or inductance for balancing. The capacitors or inductors can serve as energy storage to charge certain battery cells of the package targeted.

From the European patent EP 1 568 11 B1 For example, a system for balancing a state of charge among a plurality of series connected electric energy storage units is known. The system has a number of electric energy storage units, ie battery cells, each having a certain state of charge. In addition, the system has a circuit that monitors the state of charge of each electric energy storage unit. When the circuit detects that a single electric energy storage unit has a charge state greater than a target charge state, the circuit transfers power from that selected electric energy storage unit to the series of electric energy storage units so that the charge state of the selected unit approaches the target charge state.

The publication DE 10 2009 054 818 A1 discloses an inverter for an electrical energy storage system. The inverter has a DC link with a DC link capacitor. The DC link capacitor also serves as a buffer for a memory module compensation circuit.

The above-described prior art has the disadvantage that the resistors or the buffer memories are provided for each individual memory cell. Therefore, these balancers are complex and expensive.

It is an object of the present invention to provide an improved battery charge balance device, an improved battery management system, and an improved method of charge balance between memory cells of a battery.

This object is achieved by the battery central battery compensation device according to the present invention for a battery according to claim 1, a battery management system having such a battery central battery counterbalancing device, and claim 8, and a method of central charge balance of memory cells of a battery according to claim 11.

Further advantageous embodiments of the invention will become apparent from the subclaims and the following description of preferred embodiments of the present invention.

A central battery charge compensation device according to the invention for the charge balance of a battery having a plurality of memory cells comprises at least one central energy store for storing and discharging electrical energy. The central energy store may comprise one or more energy storage elements, such as e.g. a coil, a capacitor, a transformer or other electrical energy storage elements or mixtures thereof.

The battery may be, for example, a lithium-ion battery or another type of battery. The battery may be provided for a motor vehicle, but also for other vehicles, such as watercraft or aircraft.

The central battery charge balancing device comprises a plurality of cell controllers each electrically coupled to the central energy store, each cell controller having at least one switch for driving at least one memory cell of the battery to supply electrical energy to the memory cell from the central energy store and to transfer electrical energy from the memory cell to the memory cell remove central energy storage.

Compared with the prior art discussed at the beginning, the central battery charge compensation device according to the invention requires only a single central energy store, via which the energy can be exchanged between all the memory cells, and it is not necessary to provide energy storage elements in the individual cell controllers. The central energy storage device can also be arranged at any point and away from the battery or away from the cell controllers.

Each cell controller has at least one switch for driving at least one memory cell of the battery. Depending on the switch setting, the controlled memory cell is supplied with electrical energy / charge from the central energy store or electrical energy is / discharged from the memory cell to the central energy store. As a switch, mechanical switches and / or electrical or based on semiconductor material switches are provided. The transferred amount of electrical energy / charge for the charge balance is arbitrary in some embodiments and not limited to specific values.

In some embodiments, the battery, which may be a lithium-ion battery in particular, is composed of a plurality of memory cells. A predefined number of memory cells can in this case become a sub-packet, hereinafter also a memory cell group or sub-pack be summarized, wherein the package of sub-packages forms the entire battery. For example, four, eight, twelve, or any other number of memory cells may be grouped into such a sub-packet, with one such sub-packet each assigned a cell controller. The cell controller may then include a number of switches corresponding to the number of memory cells in the sub-packet to selectively connect the central energy storage to a single memory cell of its associated sub-packet.

In some embodiments, each memory cell has an electrically positive and an electrically negative terminal. In some embodiments, two switches are provided correspondingly for each individual memory cell, wherein a respective first switch of the two switches can electrically couple the electrically positive terminal of the memory cell to the central energy store and a second switch electrically connects the electrically negative terminal of the memory cell to the central energy store can couple.

In some embodiments, all switches are open in normal operation, so that no memory cell is electrically connected to the central energy storage. In order to electrically connect a specific memory cell electrically to the central energy store, the switches corresponding to the memory cell are closed in the charge balance mode, so that the specific memory cell to be compensated for the charge state, is electrically connected to the central energy storage. Depending on the state of charge of the memory cell, the memory cell emits electrical energy to the central energy store or it absorbs electrical energy from the central energy store until the desired state of charge of the memory cell is reached.

By appropriate control of the individual switches, electrical energy can consequently be transmitted selectively from one memory cell to the central energy store and from there to another memory cell, and vice versa.

It is therefore possible in some embodiments, an exchange of electrical energy from all memory cells with each other via the central energy storage, whereby the charge states of the individual memory cells can be compensated.

The individual cell controllers are not only electrically coupled to the memory cells assigned to them, but also to the central energy store. Different topologies are realized in the exemplary embodiments. Thus, the individual cell controllers may be serially coupled electrically to the central energy storage, i. The cell controllers are connected one behind the other in a series connection electrically to the central energy store. The individual cell controllers can also be electrically coupled in parallel to the central energy store. The serial connection of the cell controllers typically requires less wiring than the parallel connection. In the parallel connection, interruption of the electrical connection to a cell controller typically does not interrupt the electrical connection of the other cell controllers. In contrast, in the case of the serial connection, it may happen that the cell controllers, which are located after the interruption as seen from the central energy store, are no longer electrically connected to the central energy store. In some embodiments, mixed forms of serial and parallel connection of the cell controllers are realized. As a result, a flexible electrical wiring of the individual cell controller with the central electrical energy storage is possible depending on the specific requirement.

In some embodiments, the plurality of cell controllers are each configured to respectively measure the voltage of their associated memory cells. For this purpose, the cell controllers may each have a voltmeter which is coupled to the individual memory cells and measures the respective voltage of the memory cell.

The plurality of cell controllers may also each be configured to measure the temperature of their associated memory cells. For this purpose, a temperature measuring element can be arranged on each individual memory cell or, for example, in the sub-package of memory cells.

The plurality of cell controllers may also each be configured to measure the balance current flowing through the associated memory cells. This is done via a current sensor that measures the balancing current of the memory cells.

Some embodiments relate to a battery management system for a battery, for example a battery for a motor vehicle, aircraft, watercraft or the like, as already explained above. The battery typically has, as stated above, a plurality of memory cells, which may, for example, be combined into sub-packets. In addition, the battery management system comprises a central battery charge compensation device, as described above, and a controller which is set up, depending on a detected charge state of the at least one memory cell, the associated switch of the To control memory cell to supply the memory cell electrical energy from the central energy storage or dissipate electrical energy from the memory cell to the central energy storage. The control of the switch can basically be done directly by the controller of the battery management system or the controller sends a corresponding control command of the associated cell controller, which in turn controls the switch according to the control command, for example via a cell controller control.

The controller of the battery management system and / or the cell controller controller may, for example, comprise a microcontroller, processor or the like. The controller may be configured to perform a method of charge equalization as described above, or as will be described below. In addition, the controller may include a memory, such as a read-only memory or a random access memory, in which instructions for carrying out such a method are stored. In such a memory, it is also possible to store target charge values that specify a charge state for the memory cells. The target load values may also include a range of values in which the target state of charge should be.

As stated above, for example, the cell controllers may be required to determine the voltage, the current and / or the temperature or other parameters or measured values characteristic of the state of charge or the state of health, the power state or another state of the memory cell. These measured values for the memory cells can be transmitted from the cell controllers to the controller of the battery management system, wherein the controller determines a corresponding state of charge from the transmitted measured values. In accordance with the determined charge state for a memory cell, the controller may output control signals to the cell controllers, which in turn switch the switch (s) accordingly, such that electrical energy is supplied to the memory cell from the central energy store or electrical energy is removed from the memory cell until a predetermined target charge state the memory cell is reached. This can be repeated until the charge states of all memory cells of the battery are balanced.

In addition, the control of the battery management system may be submitted from the parameters such as the memory cell voltage, the memory cell current and the memory cell temperature, a state of charge (SOC), a state of health (SOH), the performance (state of function , SOF) or the like for each individual memory cell.

The control of the battery management system or the central energy storage can basically be arranged at any position, depending on which specific requirements are made. In embodiments that relate to a motor vehicle, the central energy store or the controller of the battery management system may be arranged, for example, in the engine compartment or at another suitable location. In some embodiments, the controller and / or the central energy storage, for example, be integrated in a battery terminal.

In addition, the controller and the central energy storage can be arranged on a common board. This makes it possible to arrange the central energy storage and the controller in one place together and space-saving, e.g. in a battery terminal or other suitable location. The common arrangement of control and central energy storage in one place, especially on a circuit board, in some embodiments, the wiring can be reduced, or electrical lines between the cell controllers and the central energy storage and data lines between the cell controllers and the controller can in a common Strand, which can reduce the installation effort. The control is in some embodiments, a controller for the high-voltage range, so that the central energy storage can be integrated with on the board for this control.

As stated above, the cell controllers may be configured to determine the voltage or temperature or other measured values characterizing the state of a memory cell. To transmit such measurements to the central controller of the battery management system, data transmission lines may be provided between the cell controllers and / or the controller. Existing bus systems may also be used, e.g. the customary in the automotive field CAN bus, the FlexRay bus, the LIN bus, a daisy chain or the like. In such embodiments, the cell controllers and / or the controller may be provided with a corresponding interface via which the cell controllers and the controller are interconnected via the corresponding bus and can communicate with each other.

The fact that in some embodiments, the control of the charge balance is done centrally from the control of the battery management system and also the central Energy storage is provided, in some embodiments, the cell controller can be technically very simple and come even without special electronic intelligence, since they determine only the voltage values of the memory cells in the simplest case and have only the switches for the selective connection of the memory cells with the central energy storage , In addition, even in some embodiments, the cell controllers do not require a transformer, since the electrical energy for charge balancing comes from the central energy storage and no low-voltage region must be present in the cell controller for powering electrical circuits.

A method of central charge balance of memory cells of a battery, as discussed above, comprises the following steps. First, the individual charge states of the memory cells are detected. This is done, for example, as stated above, by a corresponding voltage measurement of the memory cells by the voltmeters in the associated cell controllers. Then, memory cells are determined whose charge state is below or above a threshold value. There may be a common threshold or e.g. two thresholds, an upper threshold and a lower threshold to allow a certain range of charge state variations. Then, the memory cells thus determined are selectively connected to a central energy storage to dissipate electrical energy from the determined memory cells with a state of charge above the threshold to the central energy storage and to supply electrical energy from the central energy storage to the determined memory cells with a state of charge below the threshold , In this way, the excess electric power is transferred from the memory cells having too high a charge state to the memory cells having too low a charge state.

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

1 schematically shows a prior art passive balance battery management system;

2 schematically shows a battery management system with active balance according to the prior art;

3 schematically shows an embodiment of a battery management system in accordance with the present invention;

4 the battery management system of 3 illustrated, wherein two switches are closed, so that electrical energy flows from a memory cell with too high a charge state to the central energy storage;

5 the battery management system of 3 illustrated with two switches closed so that electrical energy flows from the central energy storage to a storage cell with too low a charge state;

6 the battery management system of 3 with all switches of a cell controller open and the charge states of the associated memory cells nearly balanced;

7 illustrates a topology in which the cell controllers are electrically connected in parallel with a central memory;

8th illustrates a topology in which the cell controllers are electrically connected in series with a central memory;

9 illustrates a topology in which a portion of the cell controllers are electrically connected in series with a central memory and a cell controller is electrically connected to the central memory in parallel with the series-connected cell controllers;

10 illustrates the common arrangement of a control of the battery management system and the central energy storage on a board;

11 FIG. 3 illustrates a flowchart for a method for the charge state equalization of memory cells of a battery.

As described above, there are two basic balancing options in the prior art, namely a passive and an active balance, which will be described below with reference to FIGS 1 and 2 be illustrated.

A battery management system 100 For a passive balancing a battery has multiple cell controllers 101 to 101n , which are each assigned six memory cells, and each via an internal control 102 . 102b , ..., 102n feature. The following is the battery management system 100 exemplified in detail in 1 illustrated cell controller 101 explained. The other cell controllers 101b to 101n are identical to the cell controller 101 constructed and they are also each associated with six memory cells of the battery.

The cell controller 101 is six memory cells 103a to 103f associated with the battery. The six memory cells 103a to 103f are each connected in series. The other, not shown memory cells of the battery close to the memory cells 103a to 103f in a further series connection. The cell controller 101 has six resistors R1 to R6, with one resistor R1, ..., R6 each having a single memory cell of the six memory cells 103a , ..., 103f , via an associated switch 104a , ..., 104f of the cell controller 101 can be coupled. The resistor R1 is thus across the switch 104a with the memory cell 103a electrically connectable, the resistor R2 via the switch 104b with the memory cell 103b , etc.

For the selective coupling of the resistors R1 to R6 with the associated memory cells 103a to 103f Each individual resistor R1 to R6 is connected to the positive electrical connection and the negative electrical connection of the associated memory cell 103a to 103f electrically connected. In the example of 1 are the associated switches 104a to 104f for connecting or disconnecting the associated resistor R1 to R6 respectively in the connection to the positive terminal of the associated memory cells 103a to 103f arranged. This allows excess electrical energy from each individual memory cell 103a , ..., 103f selectively by appropriate switching of the associated switch 104a , ..., 104f be converted into heat by the switched resistor R1, ..., R6.

For monitoring the charge state of the individual memory cells 103a to 103f has the cell controller 101 for each memory cell 103a to 103f a voltmeter V with each of the memory cells 103a to 103f voltage can be determined. These determined voltage values are sent to a Battery Management System Control (BMSS) 105 via a data line 106 transmitted, which is formed for example by a bus system, such as the CAN bus.

The BMSS 105 determined from the voltage values transmitted to each of them a charge state for the individual memory cells, the cell controllers 101 to 101n assigned. Recognize the BMSS 105 in that individual memory cells have too high a charge state, it instructs the associated cell controller or the controller of the cell controller to close the corresponding switch so that the excess electrical energy / charge from the memory cell is converted into heat via the connected resistor.

This type of passive balance thus converts electrical energy into heat, wasting the electrical energy in this way. In addition, it is not possible to increase the charge state of individual memory cells, but only the charge state of the individual memory cells can be selectively reduced to equalize the charge states of the memory cells to each other.

In the active balancing according to the prior art, which is now based on the 2 has a battery management system 200 also a number of cell controllers 201 to 201n However, instead of resisting as in passive balancing, they each have a system for active balancing in cell controllers 204a to 204n contain. This system for active balancing contains, for example, capacitances inductances or the like, in which the electrical energy from the individual memory cells 203a to 203f can be stored and from which electrical energy the memory cells 203a to 203f can be supplied. In addition, the active balance system typically includes 204a . 204b , ..., 204n also an electronic intelligence, which controls the charge balance for the memory cells, which is connected to the cell controller, or this intelligence can also in the respective cell controller control 202a . 202b , ..., 202n be settled. Otherwise, this corresponds to 2 shown battery management system 200 essentially the passive one of 1 , Again, voltage sensors V in the respective cell controllers 201 to 201n provided the voltage values of each memory cell of the battery to a central battery management system control 205 via a data line 206 send. This determines respective charge states of the individual memory cells and controls the cell controllers 201 to 201n accordingly, so that the charge states of the memory cells approach each other.

An embodiment of a battery management system according to the invention 1 with a central active balance is now using the 3 to 6 explained.

The battery management system 1 has several cell controllers 2a to 2n in each case six memory cells connected in series are associated with a battery, for example a lithium-ion battery of a motor vehicle. In the 3 to 6 are for the first cell controller 2a exemplary six memory cells 4a to 4f illustrated. To simplify matters for the other cell controllers 2 B to 2n the memory cells are not illustrated, but these are analogous to the first cell controller 2a each coupled to six memory cells and these memory cells are in series with the six memory cells 4a to 4f of the first cell controller 2a switched without the present invention being limited thereto. Even if in the present embodiment six memory cells are provided per cell controller, so the present invention is not limited thereto, but it can be assigned to a cell controller depending on the requirement, a different number of memory cells. In addition, the memory cells can also be partially connected in parallel. As stated above, in the present embodiment, the six memory cells each form a sub-package of the battery, so that each sub-package of the battery is a cell controller 2a . 2 B , ..., 2n is assigned and is electrically connected to the memory cells.

The cell controllers 2a to 2n are electrically connected in series and with a central active balancing system 6 connected, which is formed here essentially of a central energy storage. The energy store is formed for example from a capacitance or inductance, as already stated above. Depending on the requirement, the energy store may also have a plurality of energy storage elements, eg a plurality of capacitors or inductors or the like or else mixtures of different energy storage element types, for example capacitors and inductors. In addition, the central energy storage can also be formed from a transformer or be coupled for charging with a transformer. The cell controllers 2a to 2n form here together with the central energy storage 6 a central battery charge equalization device.

The central energy storage 6 communicates with a battery management system control (BMSS) 7 of the battery management system 1 , In the present embodiment, the main intelligence is to control the charge balance of the memory cells in the battery management system controller 7 ,

The BMSS 7 is via a data bus 10 , which is formed by a usual in the automotive field CAN bus, with the cell controllers 2a to 2n connected for data exchange. The cell controllers 2a to 2n each have a number of voltage sensors V which control the voltage of the individual memory cells, such as the memory cells 4a to 4f to be able to determine. Inside the cell controller 2a to 2n In addition to the voltage sensors V, a balancing current sensor and a temperature sensor for measuring the storage cell temperature are also integrated in the present exemplary embodiment. Besides, every cell controller has 2a . 2 B , ..., 2n a cell controller controller 3a . 3b , ..., 3n , The cell controller control 3a . 3b , ..., 3n in each case transmit the measured memory cell voltage values as well as the ammeter value and the temperature measured values via the data bus 10 to the BMSS 7 ,

In the present example, the BMSS receives 7 for example from the cell controller controller 3a of the first cell controller 2a the voltage values: 3.9 V for the first memory cell 4a ; 3.7V for the second memory cell 4b ; 3.9V for the third memory cell 4c ; 3.9 V for the fourth memory cell 4d ; 3.9 V for the fifth memory cell 4e ; and 4 V for the sixth memory cell 4f ,

The BMSS determine from these values 7 a charge state value of 3.9 V, therefore, the state of charge of the second memory cell 4b with 3.7 V in this regard is too low and the charge state of the sixth memory cell 4f with 4 V is too high.

Every cell controller 2a . 2 B , ..., 2n has a number of switches that allow the memory cells selectively with the central energy storage 6 electrical can be coupled. In the case of the first cell controller 2a these are the switches 5a to 5g (the other cell controllers 2 B , ..., 2n are constructed analogously).

In the present embodiment, a switch is always more provided as memory cells are present. It is at every memory cell 4a . 4b , ..., 4f in each case a switch on the positive electrical connection and a switch on the negative connection of the storage cell 4a . 4b , ..., 4f intended.

The memory cell 4a is therefore selective over the switches 5a and 5b with the central energy storage 6 electrically connectable, the memory cell 4b over the switches 5b and 5c , ..., and finally the memory cell 4f over the switches 5f and 5g , Every cell controller 2a . 2 B , ..., 2n is over two electrical wires 9a and 9b with the central energy storage 6 electrical connected. The cell controllers 2a . 2 B , ..., 2n are electrically connected in series in this embodiment.

In addition, the memory cells 4a to 4f along with the switches 5a to 5g electrically with the electrical wires 9a and 9b leading to the central energy storage 6 lead, connected. So that's the first switch 5a connected to the positive terminal of the first memory cell 4a is coupled, via a line branch 8a with the electric wire 9a connected. The second switch 5b which is between the negative terminal of the first memory cell 4a and the positive terminal of the second memory cell 4b is coupled via a line branch 8b with the electric wire 9b connected. The third switch 5c which is between the negative terminal of the second memory cell 4b and the positive terminal of the third memory cell 4c is coupled via a line branch 8c with the electric wire 9a connected. Similarly, the switch 5d over the line branch 8d and the switch 5f over the line branch 8f with the electric wire 9b connected and the switches 5e and 5g are over the line branches 8e respectively. 8g with the electric wire 9a connected. The switches 5a to 5g are therefore alternating with the electric wire 9a respectively. 9b over the line pointer 8a to 8g connected.

For example, the excess electrical energy of the sixth memory cell 4f to the central energy storage 6 to transfer the switch 5f that is connected to the positive terminal of the memory cell 4f coupled, and the switch 5g connected to the negative terminal of the memory cell 4f is coupled, closed (see circle with reference numerals 12 in 4 ). This will be the memory cell 4f with the central energy storage 6 connected and the excess electrical energy is in the central energy storage 6 saved. The switches 5f and 5g remain closed until in the memory cell 4f the desired target charge value, in this case 3.9V, is reached. After that, these switches 5f and 5g opened again.

Next will be in the energy store 6 stored electrical energy of the second memory cell 4b fed. This will be the switch 5b connected to the positive electrical connection of the memory cell 4b is electrically coupled, and the switch 5c connected to the negative electrical connection of the memory cell 4b is coupled, closed (see circle with reference numerals 13 in 5 ). Once in the central energy storage 6 stored electrical energy of the second memory cell 4b is supplied or as soon as the desired state of charge is reached, the two switches 5b and 5c opened again (see circle with reference number 13 in 6 ). In the illustrated example, the memory cell now has 4b a voltage of 3.8 V. Overall, so the voltage of the last memory cell 5f lowered by 0.1 V and the voltage of the second memory cell 5b increased by 0.1 V, with the electric energy through the central energy storage 6 was conducted.

Although in the present embodiment there is shown an exchange of electrical energy of memory cells managed by one and the same cell controller, the present invention is not limited thereto. By using the central energy storage 6 and the electrical connection of all memory cells via all cell controllers 2a to 2n with the central energy storage, it is possible to transfer electrical energy between any memory cells via the central energy storage.

In the present embodiment, the central control is the balancing of the memory cells in the BMSS 7 settled. The BMSS 7 receives inter alia the voltage values of the memory cells from the cell control controllers 3a . 3b , ..., 3n the cell controller 2a . 2 B , ..., 2n over the data bus 10 , The BMSS 7 analyzes the received voltage values and other values such as the battery current, the memory cell temperature, and the like, and determines from them which memory cells have too high or too low a charge state. The BMSS compares 7 the charge states with an upper and a lower predetermined threshold. If the state of charge of a memory cell lies above the upper or lower threshold value, it controls the corresponding associated cell controller, which in turn switches the switches so that either electrical energy is dissipated from the memory cell to the central energy store or electrical energy from the central one Energy storage is supplied to either reduce or increase the state of charge.

As stated above, the memory cells determined in the example discussed are the last memory cell 4f which originally had too high a state of charge with a voltage of 4.0 V and the second memory cell 4b , which originally had too low a state of charge with a voltage of 3.7 V (see 3 ).

This is the BMSS 7 fixed and accordingly has the cell controller control 3a over the data bus 10 on, first the switches 5f and 5g close, so that too high charge state of the last memory cell 4f is degraded and the electrical energy in the central energy storage 6 is stored. Once this is achieved, the BMSS points 7 the cell controller control 3a of the first cell controller 2a on, these switches 5f and 5g to open. Then reject the BMSS 7 the cell controller control 3a of the first cell controller 2a on, the two switches 5b and 5c close, so that in the central energy storage 6 stored electrical energy from the central energy storage 6 in the second memory cell 4b flows and there increases the state of charge. Once the of the BMSS 7 predetermined charge state is reached or in the central energy storage 6 store electrical energy completely to the memory cell connected to it 4b submitted, rejects the BMSS 7 the cell controller 2a on, the switches 5b and 5c to open.

The procedure described above is performed by the BMSS 7 until the charge states of all memory cells are balanced. In the present embodiment, the complete control sovereignty in the BMSS 7 settled.

In other embodiments, the control over the charge balance may also be (partially) located in the cell controllers themselves and / or in the central energy store. For example, the balancing of the charge states outlined above may be used instead of the BMSS 7 also from one with in the central energy storage 6 settled balance control. In that case, the BMSS communicates 7 via a data bus 11 (dashed arrows in the 3 to 6 ) with the balance control 6 , In the case, for example, the BMSS 7 the balance control 6 to start the charge balance. When the balance control 6 finished, she tells the BMSS.

In yet other embodiments, each cell controller control is 3a . 3b , ..., 3n the single cell controller 2a . 2 B , ..., 2n designed so that it can perform the charge balancing of the memory cells. However, there is an intensive data and control command exchange between the cell controllers 2a . 2 B , ..., 2n necessary because they have to inform each other about the charge states of the memory cells, and the cell controller controls 3a . 3b , ..., 3n must be designed intelligently, which makes them expensive and expensive.

In the embodiment of 3 to 6 are the cell controllers 2a . 2 B , ..., 2n in series to the central energy storage 6 connected.

The cell controllers can also be connected in parallel to the central energy store, as in 7 is illustrated. In the battery charge equalization device 20 of the 7 are cell controllers 21a . 21b , ..., 21n which are essentially identical to the cell controllers 2a . 2 B , ..., 2n , which in connection with the embodiment of the above 3 to 6 described in parallel via lines 24a . 24b , ..., 24n to a central energy storage 23 connected. The central energy storage 23 can, as stated above, by a capacitance, inductance or the like are formed. The cell controllers 21a . 21b , ..., 21n each manage six memory cells, each one sub-packet 22a . 22b , ..., 22n form, as also discussed above.

The cell controllers can also be connected in series to the central energy store, as in 8th is illustrated. In the battery charge equalization device 30 of the 8th are cell controllers 31a . 31b , ..., 31n which are essentially identical to the cell controllers 2a . 2 B , ..., 2n , which in connection with the embodiment of the above 3 to 6 are in series over a wire 34 to a central energy storage 33 connected. The central energy storage 33 can, as stated above, by a capacitance, inductance or the like are formed. The cell controllers 31a . 31b , ..., 31n each manage six memory cells, each one sub-packet 32a . 32b , ..., 32n form.

However, the cell controllers can also be connected in series and in parallel to the central energy store, as can be seen in FIG 9 is illustrated. In the battery charge equalization device 40 of the 9 are cell controllers 41a . 41b , ..., 41n provided, which are essentially identical to the cell controllers 2a . 2 B , ..., 2n , which in connection with the embodiment of the above 3 to 6 are described are. The first cell controller 41a is parallel to series-connected cell controllers 41b , ..., 41n with a central energy storage 43 connected. The first cell controller 41a is over the line 44a with the central energy storage 43 connected and the remaining cell controllers 41b , ..., 41n are over a line 44b with the central energy storage 43 connected in series. The cell controllers 41a . 41b , ..., 41n each manage six memory cells, each one sub-packet 42a . 42b , ..., 42n form.

The person skilled in the art will appreciate that, depending on the requirement, he can connect the cell controllers in series, in parallel or in mixed forms between serial and parallel circuits to the central energy store.

An embodiment of a battery management system 50 in which a central energy storage 51 and a battery management system control (BMSS) 52 on a common board 53 are arranged in 10 illustrated.

The central energy storage 51 is designed as a transformer. The central energy storage 51 has an electrical connection 54 who is the cell controller of the battery management system 50 leads, as in connection with the 3 to 9 have been explained. The BMSS 52 has a data output 55 which can receive data from the cell controllers and transmit control signals to them. The BMSS 52 In some embodiments, it includes a processor, a (read only) memory, an interface for connection to a data bus, such as a CAN bus, LIN bus, FlexRay, daisy chain, or the like, as well known to those skilled in the art. The BMSS 52 may also be configured to charge the central energy storage 51 on the board 53 to monitor. The BMSS 52 can be configured in some embodiments as a high-voltage control unit, so that the central energy storage (eg transformer) is arranged together with the high-voltage control unit on a common board.

The BMSS 52 is accordingly set up to control the charge states of battery To compensate for memory cells, as exemplified in connection with the embodiment of 3 to 6 has been explained above, in which they the central energy storage 51 selectively connects to the individual battery storage cells. The BMSS 52 In particular, it can also be set up in the following and in connection with 1 to carry out the described method.

The procedure begins at 70 and at first 71 the charge states of memory cells of a battery, in particular a lithium-ion battery, determined by a controller, such as the control described above, a battery management system or a controller that is responsible for the charge balance. For this purpose, for example, voltage values are determined by the individual memory cells and compared with a voltage threshold value or charge state target value.

at 72 It is then determined which memory cells of the battery have a charge state above the voltage threshold and which have a charge state below the voltage threshold, as has already been explained in detail above.

at 73 Then, electric energy is dissipated from the memory cells having a state of charge above the voltage threshold to a central energy storage as described above, and electrical energy is supplied from the central energy storage to the storage cells having a state of charge below the voltage threshold by selectively connecting the respective memory cells to the memory cell be connected central energy storage. This is repeated until all memory cells have reached the desired state of charge, ie until, for example, all memory cells have reached a predetermined target state of charge. The target state of charge may be determined by a single value or by a value interval, as stated above. When all memory cells have reached the target state of charge, the process ends at 74 ,

LIST OF REFERENCE NUMBERS

1

Battery Management System

2a, 2b, 2n

cell controller

3a, 3b, 3n

Cell controller control

4a to 4f

memory cells

5a to 5g

switch

6

Central energy storage

7

Battery management system control

8a to 8g

Electric branches

9a, 9b

Electrical connection line

10

bus

11

Data Connection

12

switch 5f and 5g on / off

13

switch 5b and 5c on / off

20

Battery charge equalization device (parallel version)

21a, 21b, 21n

 cell controller

22a, 22b, 22n

 memory cells

23

Central energy storage

24a, 24b, 24c

 Parallel connection branches

30

Battery Charge Compensation Device (Serial Type)

31a, 31b, 31n

 cell controller

32a, 32b, 32n

 memory cells

33

Central energy storage

34

Electrical connection

40

Battery charge equalization device (mixed version)

41a, 41b, 41n

 cell controller

42a, 42b, 42n

 memory cells

43

Central energy storage

44a, 44b

Electrical connection branches

50

Battery Management System

51

Central energy storage

52

Battery management system control

53

Common board

54

Electrical connection to the central energy storage

55

Data bus connection to the BMSS

70-74

Procedural steps of the flowchart 11

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

• DE 102010039913 A1 [0008]
• WO 2011/078478 A2 [0010]
• WO 2012/119297 A1 [0011]
• EP 156811 B1 [0012]
• DE 102009054818 A1 [0013]

Claims (11)

Central battery charge equalization device for charge equalization of a battery with multiple memory cells ( 4a , ..., 4f ; 22a , ..., 22n ; 32a , ..., 32n ; 42a , ..., 42n ), comprising: - at least one central energy store ( 6 . 23 . 33 . 43 . 51 ) for storing and dispensing electrical energy; Several cell controllers ( 2a , ..., 2n ; 21a ; ..., 21n ; 31a , ..., 31n ; 41a , ..., 41n ), each with the central energy storage ( 6 . 23 . 33 . 43 . 51 ) are electrically coupled, each cell controller ( 2a , ..., 2n ; 22a ; ..., 22n ; 32a , ..., 32n ; 42a , ..., 42n ) at least one switch ( 5a , ..., 5g ) for driving at least one memory cell ( 4a , ..., 4f ; 22a , ..., 22n ; 32a , ..., 32n ; 42a , ..., 42n ) of the battery to the memory cells ( 4a , ..., 4f ; 22a , ..., 22n ; 32a , ..., 32n ; 42a , ..., 42n ) electrical energy from the central energy store ( 6 . 23 . 33 . 43 . 51 ) and electrical energy from the memory cells ( 4a , ..., 4f ; 22a , ..., 22n ; 32a , ..., 32n ; 42a , ..., 42n ) to the central energy store ( 6 . 23 . 33 . 43 . 51 ) dissipate. Central battery charge compensation device according to claim 1, wherein in each case a cell controller ( 2a , ..., 2n ; 21a ; ..., 21n ; 31a , ..., 31n ; 41a , ..., 41n ) a plurality of memory cells ( 4a , ..., 4f ; 22a , ..., 22n ; 32a , ..., 32n ; 42a , ..., 42n ) is assigned to the battery and in each case a cell controller ( 2a , ..., 2n ; 21a ; ..., 21n ; 31a , ..., 31n ; 41a , ..., 41n ) a corresponding number of switches ( 5a , ..., 5g ), so that in each case one of the plurality of memory cells ( 4a , ..., 4f ; 22a , ..., 22n ; 32a , ..., 32n ; 42a , ..., 42n ) to which the cell controller ( 2a , ..., 2n ; 21a ; ..., 21n ; 31a , ..., 31n ; 41a , ..., 41n ) is selectively associated with the central energy store ( 6 . 23 . 33 . 43 . 51 ) can be electrically coupled. Central battery charge compensation device according to one of the preceding claims, wherein the cell controller ( 2a , ..., 2n ; 21a ; ..., 21n ; 31a , ..., 31n ; 41a , ..., 41n ) each one switch ( 5a , ..., 5g ) for a positive electrical connection of a memory cell ( 4a , ..., 4f ; 22a , ..., 22n ; 32a , ..., 32n ; 42a , ..., 42n ) and a switch ( 5a , ..., 5g ) for a negative electrical connection of a memory cell ( 4a , ..., 4f ; 22a , ..., 22n ; 32a , ..., 32n ; 42a , ..., 42n ) having. A battery central battery compensation device according to any one of the preceding claims, wherein the plurality of cell controllers ( 2a , ..., 2n ; 31a , ..., 31n ; 41a , ..., 41n ) at least partially in series with the central energy store ( 6 . 23 . 33 . 43 . 51 ) are electrically coupled. A battery central battery compensation device according to any one of the preceding claims, wherein the plurality of cell controllers ( 21a ; ..., 21n ; 41a , ..., 41n ) at least partially in parallel with the central energy store ( 6 . 23 . 33 . 43 . 51 ) are electrically coupled. A battery central battery compensation device according to any one of the preceding claims, wherein the plurality of cell controllers ( 2a , ..., 2n ) are each arranged to respectively control the voltage of the memory cells assigned to them ( 4a , ..., 4f ) to eat. A battery central battery compensation device according to any one of the preceding claims, wherein the plurality of cell controllers ( 2a , ..., 2n ) are each arranged to respectively the temperature of their associated memory cells ( 4a , ..., 4f ) to eat. A battery management system for a battery having a plurality of memory cells, comprising a central battery charge compensation device according to one of the preceding claims and a controller ( 7 ; 52 ), which is set up in dependence on a recognized charge state of the at least one memory cell ( 4a ; ..., 4f ) the corresponding switch ( 5a , ..., 5g ) of the associated cell controller ( 2a , ..., 2n ) to the memory cell ( 4a ; ..., 4f ) electrical energy from the central energy store ( 6 ; 51 ) or electrical energy from the memory cell ( 4a ; ..., 4f ) to the central energy store ( 6 ; 51 ) dissipate. A battery management system according to claim 8, wherein the controller ( 52 ) and the central energy store ( 51 ) on a common board ( 53 ) are arranged. Battery management system according to one of claims 8 or 9, wherein the central energy store ( 51 ) is designed as a transformer. A method of central charge balancing of memory cells of a battery, comprising: detecting ( 71 ) of charge states of the memory cells; Determine ( 72 ) of memory cells having a charge state below or above a threshold value; Selective connection ( 73 ) of the determined memory cells with a central energy storage to dissipate electrical energy from the determined memory cells with a charge state above the threshold value to the central energy storage and to supply electrical energy from the central energy storage to the determined memory cells with a charge state below the threshold value.

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