WO2014154495A1

WO2014154495A1 - Energy storage device and system having an energy storage device

Info

Publication number: WO2014154495A1
Application number: PCT/EP2014/054948
Authority: WO
Inventors: Waleed SAHHARY; Alexander Schmidt
Original assignee: Robert Bosch Gmbh
Priority date: 2013-03-28
Filing date: 2014-03-13
Publication date: 2014-10-02
Also published as: CN105052029A; DE102013205562A1; CN105052029B

Abstract

The invention relates to an energy storage device which is designed to provide and/or receive electrical energy in the form of an n-phase current and an n-phase voltage, where n ≥ 1. The energy storage device comprises n energy supply branches, wherein each of the energy supply branches has a multiplicity of energy storage modules connected in series. The energy storage modules each comprise an energy storage cell coupling module with coupling module connections and a coupling device with coupling elements which are designed to selectively connect the energy storage cell module to the particular energy supply branch via the coupling module connections or to circumvent the energy storage cell module in the particular energy supply branch. Each of the energy storage cell coupling modules in turn has a line of coupling modules with a multiplicity of energy storage cell branch modules which are connected in series and have an energy storage cell branch with a series circuit comprising an energy storage cell branch coupling element and at least one energy storage cell and a circumvention branch coupling element which is connected in parallel with the energy storage cell branch.

Description

Description title

Energy storage device and system with an energy storage device

The invention relates to an energy storage device, in particular one

Energy storage device with modular battery system for any stationary and mobile applications, as well as a system with an energy storage device.

State of the art

It is becoming apparent that in the future both stationary applications, e.g.

Wind turbines or solar systems, as well as in vehicles, such as hybrid or

Electric vehicles, increasingly electronic systems are used that integrate elements of power electronics in the energy storage system.

The feeding of multiphase electricity into an electric machine becomes

Usually accomplished by a converter in the form of a pulse inverter. For this purpose, one provided by a DC voltage intermediate circuit

DC voltage in a multi-phase AC voltage, for example, a three-phase AC voltage to be reversed. The DC link is in this case of a string of serially interconnected battery modules or arbitrary

Fed with DC voltage sources.

In order to meet the power and energy requirements of a given application, multiple battery modules or battery cells are often connected in series in an energy storage system.

The rigid series connection of several battery modules involves the problem that the entire string fails if a single battery module fails. Such a failure of the power supply string can lead to a failure of the entire system. Furthermore, temporarily or permanently occurring power reductions of a single battery module can lead to power reductions in the entire power supply line.

In the documents US 5,642,275 A1 and US 6,969,967 B2 battery systems are described with integrated inverter function. Systems of this type are under the Name Cascaded Multilevel Inverter or also Battery Direct Inverter (Battery Direct Inverter, BDI) known. Such systems include DC sources in multiple energy storage module strings which are directly connectable to an electrical machine or electrical network. In this case, single-phase or multi-phase supply voltages can be generated. The energy storage module strands in this case have a plurality of energy storage modules connected in series, each energy storage module having at least one energy storage cell and an associated controllable coupling unit, which makes it possible to interrupt the respective energy storage module strand depending on control signals or to bridge the respectively associated at least one energy storage cell or each associated with at least one energy storage cell to switch into the respective energy storage module string. By suitable control of the coupling units, for example by means of

Pulse width modulation, also suitable phase signals for controlling the phase output voltage can be provided, so that a separate

Pulse inverter can be dispensed with. The to control the

Phase output required pulse inverters is thus integrated so to speak in the BDI.

BDIs usually have higher efficiency and higher

Reliability against conventional systems. The reliability is ensured, inter alia, that defective, failed or not fully efficient battery cells by suitable bridging control of the

Coupling units can be switched out of the power supply lines. The phase output voltage of an energy storage module string can be varied by appropriate activation of the coupling units and in particular be set in stages. The gradation of the output voltage results from the voltage of a single energy storage module, the maximum possible

Phase output voltage by the sum of the voltages of all

Energy storage modules of an energy storage module string is determined.

The publications DE 10 2010 027 857 A1 and DE 10 2010 027 861 A1, for example, disclose battery direct inverters with a plurality of battery module strings, which can be connected directly to an electrical machine. The energy storage module strands in this case have a plurality of energy storage modules connected in series, each energy storage module having at least one energy storage cell and an associated controllable coupling unit, which allows the respectively associated at least one in response to control signals Energy storage cell to bridge or switch the respectively associated at least one energy storage cell in the respective energy storage module string. Optionally, the coupling unit can be designed such that it additionally allows to switch the respective assigned at least one energy storage cell with inverse polarity in the respective energy storage module string or the respective

To interrupt energy storage module strand on the submodule and to bridge this at the same time or to bridge the respectively associated at least one energy storage cell.

To set an output voltage of an energy storage module, a pulse-width-modulated (PWM) control of the coupling units can take place. This makes it possible to output a desired mean value as energy storage module voltage by specific variation of the on or off times.

BDIs with a high number of coupling units often have higher

Leakage losses, which reduce the efficiency of the BDI, especially at high load currents.

There is therefore a need for solutions for energy storage devices of modular design that can reduce the number of power switches required, can be used without pulse width modulated drive methods, and enable more flexible charge drive strategies.

Disclosure of the invention

The present invention, in one aspect, provides an energy storage device configured to provide and / or receive electrical energy in the form of an n-phase current and an n-phase voltage, where n> 1. The

Energy storage device comprises n phases, wherein the energy storage device may comprise, for example, three phases in star or delta connection. Each of the phases includes a plurality of series connected energy storage modules. The energy storage modules each comprise an energy storage cell coupling module with coupling module connections, and a coupling device with coupling elements which are designed to selectively switch the energy storage cell module via the coupling module connections into the respective energy supply branch or to bypass the respective energy supply branch. Each of the energy storage cell coupling modules in turn has a coupling module string with a plurality of series-connected energy storage cell branch modules having an energy storage cell branch a series circuit of an energy storage cell branch coupling element and at least one energy storage cell and a parallel to the

Have energy storage cell branch switched bypass branch coupling element.

In another aspect, the present invention provides a system having an n-phase electric machine, where n> 1, an energy storage device configured to provide and / or receive electrical energy in the form of an n-phase current and an n-phase voltage and having n power supply branches connected in parallel, each coupled between an output terminal and a reference potential rail, each of the

Power supply branches a variety of series-connected

Having energy storage modules. The energy storage modules each comprise an energy storage cell module, which has at least one energy storage cell, and a coupling device with coupling elements, which are designed to selectively switch or bypass the energy storage cell module in the respective energy supply branch. The system further comprises n phase lines, each of which couples one of the output terminals of the energy storage device to each one of n phase terminals of the n-phase electric machine, and a control device configured to perform a method according to the invention.

Advantages of the invention

It is idea of the present invention, a modular design

Energy storage device to be constructed such that the number of coupling units can be minimized. This is achieved by constructing the energy storage cell modules of each energy storage module of an energy storage device in turn in a battery direct converter topology (BDC).

In this context, battery direct converter topology means that the

Energy storage cell modules of the individual energy storage modules have a series circuit of energy storage cells, which are assigned via memory module internal

Coupling units selectively switched into the series circuit or can be bypassed in this. Thereby, the energy storage device has a hierarchical nesting structure in which a plurality of BDCs as

Energy storage cell modules are combined in a BDI. Each of the energy storage modules can be variably modulated in its module output voltage, whereby the granularity of the total output voltage of a

Energy supply strand of the energy storage device set much finer can be used without having to resort to a PWM control of individual energy storage modules.

This has the advantage that the silicon cost with increasing number of

Energy storage cells over known topologies with full bridge circuits for each of the energy storage cells can be reduced.

Furthermore, it is advantageously possible to almost any output voltages and energy storage capacities on the basis of similar building blocks for the

To realize energy storage modules by suitable modular hierarchical structuring of the energy storage device.

Another advantage of this topology is the realization of very small values of Total Harmonic Distortion (THD) by adjusting the set voltage in the output voltage. This adaptive grading can be achieved by changing the

DC link voltage certain energy storage modules and by the ability to cascade by means of full bridges energy storage modules in positive and negative polarity can be realized.

Due to the hierarchical structure can continue to take place within an energy storage module, a charging process for individual energy storage cells, while the

Energy storage module itself is still in operation, i. others of the energy storage cells contribute to the output voltage of a power supply branch. As a result, on the one hand, the availability of the entire system can be optimized. On the other hand, this makes it possible to easily balance due to aging effects of the individual energy storage cells, what the overall supply capacity of

Energy storage device considerably improved. In addition, it is possible the

Heat distribution within the energy storage device very precise and flexible to regulate.

According to one embodiment of the energy storage device according to the invention, the coupling devices may comprise coupling elements in full-bridge connection. Alternatively, the coupling devices may comprise coupling elements in a half-bridge circuit.

According to a further embodiment of the invention

Energy storage device, the energy storage cells lithium-ion Accumulators, double-layer capacitors, electrolytic capacitors or similar energy storage components include.

According to a further embodiment of the invention

Energy storage device, the coupling elements, the

Energy storage cell branch coupling elements and / or the

Bypass couplers include power semiconductor switches.

It can according to another embodiment of the invention

Energy storage device, the power semiconductor switches insulated gate bipolar transistors, IGBT, junction field effect transistors, JFET, or metal oxide semiconductor field effect transistors, MOSFET include.

According to one embodiment of the system according to the invention, the n-phase electric machine may comprise a synchronous machine or a switched reluctance machine.

Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings.

Brief description of the drawings

Show it:

Fig. 1 is a schematic representation of a system with a

Energy storage device according to an embodiment of the present invention;

Fig. 2 is a schematic representation of an embodiment of a

Energy storage module of an energy storage device according to Fig. 1;

Fig. 3 is a schematic representation of another embodiment of a

Energy storage module of an energy storage device according to Fig. 1;

Fig. 4 is a schematic representation of an embodiment of a

Energy storage cell coupling module of an energy storage module according to Fig. 2 or 3; Fig. 5 is a schematic representation of an embodiment of a

Energy storage cell branch module of a

Energy storage cell coupling module according to Fig. 4; and FIG. 6 shows a schematic illustration of an embodiment variant for a

Energy storage device.

1 shows a system 100 for voltage conversion of DC voltage provided by energy storage modules 3 into an n-phase AC voltage. The system 100 comprises an energy storage device 1 with energy storage modules 3, which in

Power supply branches are connected in series, whereby electrical energy can be provided and / or absorbed by the energy storage device 1 in the form of an n-phase current and an n-phase voltage. By way of example, three energy supply branches Z1, Z2 and Z3 are shown in FIG. 1, which are suitable for generating a three-phase alternating voltage, for example for a three-phase machine. However, it is clear that any other number of power supply branches may be possible as well. The energy storage device 1 has at each

Power supply branch via an output terminal 1 a, 1 b, 1 c, which are respectively connected to phase lines 2a, 2b and 2c, which couple the energy storage device 1 with an electric machine 2. By way of example, the system 100 in FIG. 1 serves to supply an electric machine 2. However, it can also be provided that the energy storage device 1 is used for buffering electric current for a

Power supply network 2 is used. The system 100 may further include a controller 6 connected to the energy storage device 1 and by means of which the

Energy storage device 1 can be controlled to the desired

Output voltages to the respective output terminals 1 a, 1 b, 1 c provide. The power supply branches Z1, Z2 and Z3 can at their end with a

Reference potential 4 (reference rail) are connected. This can lead to an average potential with respect to the phase lines 2a, 2b, 2c of the electric machine 2 and, for example, be connected to a ground potential. It can do that

Reference potential 4, for example, be coupled to the neutral point 4a of the electric machine 2. Each of the power supply branches Z1, Z2 and Z3 has at least two energy storage modules 3 connected in series. By way of example, the number of energy storage modules 3 per power supply branch in FIG. 1 is three, but any other number of energy storage modules 3 is also possible. Preferably In this case, each of the energy supply branches Z1, Z2 and Z3 comprises the same number of energy storage modules 3, but it is also possible for each

Energy supply branch Z1, Z2 and Z3 a different number

Provide energy storage modules 3.

The energy storage modules 3 each have two output terminals 3a and 3b, via which an output voltage of the energy storage modules 3 can be provided. This aforementioned output voltage can be set independently of the voltage level of the DC voltage source in the energy storage module 3.

Exemplary construction forms of the energy storage modules 3 are shown in greater detail in FIGS. 2 and 3. The energy storage modules 3 each comprise one

Coupling device 7 with a plurality of coupling elements 7a and 7c and optionally 7b and 7d. The energy storage modules 3 further include one each

Energy storage cell coupling module 5 with one or more series-connected energy storage cell branch modules 15, as explained in more detail below in connection with FIGS. 4 and 5 below.

The energy storage cell coupling modules 5 are connected via coupling module connections 5a, 5b to input terminals of the associated coupling device 7. The

Coupling device 7 is exemplified in FIG. 2 as a full bridge circuit with two coupling elements 7a, 7c and two coupling elements 7b, 7d. The

Coupling elements 7a, 7b, 7c, 7d can each have an active switching element, for example a power semiconductor switch, and a freewheeling diode connected in parallel with it. The power semiconductor switches can, for example

Field effect transistors (FETs) have. In this case, the freewheeling diodes can also be integrated in each case in the power semiconductor switch.

The coupling elements 7a, 7b, 7c, 7d in Fig. 2 can be controlled in such a way, for example by means of the control device 6 in Fig. 1, that the

Energy storage cell coupling module 5 is selectively connected between the output terminals 3a and 3b or that the energy storage cell coupling module 5 is bypassed in the respective power supply branch Z1, Z2, Z3 or bridged. For example, the energy storage cell coupling module 5 in the forward direction between the

Output terminals 3a and 3b are switched by the coupling element 7d bottom right and the coupling element 7a top left are placed in a closed state, while the other two coupling elements are placed in an open state. A bypass state may be, for example be adjusted by the two coupling elements 7a and 7b are placed in the closed state, while the two coupling elements 7c and 7d are held in the open state.

By suitable activation of the coupling devices 7 can therefore individual

Energy storage cell coupling modules 5 of the energy storage modules 3 targeted in the

Series connection of a power supply branch Z1 to Z3 are integrated.

3 shows a further exemplary embodiment of an energy storage module 3. The energy storage module 3 shown in FIG. 3 differs from the energy storage module 3 shown in FIG. 2 only in that the coupling device 7 has two instead of four coupling elements which are in half-bridge instead of full-bridge are interconnected.

Fig. 4 shows a schematic representation of an embodiment of a

Energy storage cell coupling module 5 of an energy storage module 3 of FIG. 2 or 3. The energy storage cell coupling module 5 has a coupling module string Z with a plurality of series-connected energy storage cell branch modules 15. The energy storage cell branch modules 15 each have branch module connections 15a, 15b, via which the energy storage cell branch modules 15 are connected in series. The number of energy storage cell branch modules 15 per

Energy storage cell coupling module 5 is shown in Fig. 4 by way of example with three, but each other number of energy storage cell branch modules 15 per

Energy storage cell coupling module 5 may also be possible.

As further shown in FIG. 5, each of the energy storage cell branch modules 15 includes a similar topology to the energy storage module 3 shown in FIG. the energy storage cell branch modules 15 each include one

Energy storage cell branch 16 and a parallel to the energy storage cell branch 16 connected bypass branch coupling element 17a. The energy storage cell branch 16 in this case comprises a series circuit comprising an energy storage cell branch coupling element 17c and at least one energy storage cell 16a, 16k. The

Energy storage cell branch coupling element 17c and the bypass branch coupling element 17a form a half-bridge circuit via which the energy storage cell branch 16 can be selectively connected to the energy storage cells 16a, 16k in the coupling module strand Z or bypassed or bypassed in that. The energy storage cell branch module 15 can, for example, be connected in series with batteries 16a, 16k, for example lithium-ion batteries or accumulators,

Double layer capacitors or electrolytic capacitors have. In this case, the number of energy storage cells 16a, 16k in that shown in Fig. 5

Energy storage cell branch module 15 exemplified two, but any other number of energy storage cells 16a, 16k is also possible.

In the illustrated embodiments, the active switching elements as

Power semiconductor switches, for example in the form of IGBTs (Insulated Gate Bipolar Transistors), JFETs (Junction Field Effect Transistors) or as MOSFETs (Metal Oxide Semiconductor Field-Effect Transistors), be executed.

Thus, each of the energy storage cell coupling modules 5 is in a sense constructed as a battery direct converter (BDC). By setting different

Coupling states of the energy storage cell branch coupling elements 17c and the

By-pass branch coupling elements 17a per energy storage cell branch module 15, different output voltages for each of the energy storage cell coupling modules 5 can be realized without relying on a pulse width modulation (PWM) method.

must be resorted to. The number of power semiconductor switches required is reduced since only two coupling elements per energy storage cell branch module 15 are necessary in each case. This automatically implies a reduction of the

On resistance of each energy storage cell coupling module 5, since each

Energy storage cell 16a, 16k in the coupling module string Z is separately on and coupled out. Within a power supply branch Z1 to Z3 is thus a simultaneous charging and discharging of different energy storage cells 16a, 16k possible. This increases, for example, the range of a traction battery in which a

Energy storage device 1 is used, in particular at different aged internal resistances of the energy storage cells 16a, 16k. Can do this

Energy storage cell branch modules 15, whose energy storage cells 16a, 16k have an above-average overvoltage under load near the lower termination voltage, are supported by the remaining energy storage cell branch modules 15.

The use of such an energy storage device 1 makes it possible to provide an n-phase supply voltage, for example for an electrical machine 2

provide. For this purpose, phase lines 2a, 2b, 2c with respective of

Output terminals 1 a, 1 b, 1 c are connected, wherein the phase lines 2a, 2b, 2c are in turn connected to phase terminals of the electric machine 2 can. For example, the electric machine 2 may be a three-phase electric machine, for example a three-phase asynchronous machine

Synchronous machine or a switched reluctance machine, which has 2d inductors 2d above the machine.

The energy storage device 1 can, for example, with a regenerative

Energy source, e.g. a photovoltaic module, and / or a local or central power grid, e.g. House connection of the energy supplier, be coupled. Furthermore, the energy storage device 1 may be connected to the electric generator of a coupled heat and power system and / or a local or central power grid, e.g.

House connection of the energy supplier, be connected. Of course, it may also be possible to connect the energy storage device 1 with any combination of systems of electrical power supply. Fig. 6 shows a schematic representation of an embodiment of a

Energy storage device when connecting to a three-phase electrical machine. For example, the energy storage device in Fig. 6 according to the technical specifications with reference to Figs. 1 to 5 can be realized.

Claims

claims

1 . Energy storage device (1), which for providing and / or recording

electrical energy in the form of an n-phase current and an n-phase voltage, where n> 1, with:

n power supply branches (Z1; Z2; Z3), each of the

Power supply branches (Z1; Z2; Z3) comprises a plurality of series-connected energy storage modules (3), each comprising:

an energy storage cell coupling module (5) with coupling module connections (5a, 5b),, and

a coupling device (7) with coupling elements (7a; ...; 7d) which are designed to switch the energy storage cell module (5) selectively via the coupling module connections (5a, 5b) into the respective energy supply branch (Z1; Z2; Z3) in the respective energy supply branch (Z1; Z2; Z3),

wherein each of the energy storage cell coupling modules (5) comprises:

a coupling module strand (Z) with a plurality of series-connected

Energy storage cell branch modules (15) having an energy storage cell branch (16) with a series circuit of a Energiepeicherzellenzweigkoppelelement (17c) and at least one energy storage cell (16a, 16k) and a parallel to the energy storage cell branch (16) connected bypass branch coupling element (17a).

2. Energy storage device (1) according to claim 1, wherein the energy storage device (1) has three phases, which are connectable via output terminals (1 a; 1 b; 1 c) with an electrical machine (2) in star or delta connection.

3. Energy storage device (1) according to claim 1 or 2, wherein the

Coupling devices (7) comprise coupling elements (7a; 7b; 7c; 7d) in full-bridge connection.

4. Energy storage device (1) according to claim 1 or 2, wherein the

Coupling devices (7) comprise coupling elements (7a, 7c) in a half-bridge circuit.

5. Energy storage device (1) according to one of claims 1 to 4, wherein the

Energy storage cells (16a, 16k) lithium-ion batteries,

Double layer capacitors or electrolytic capacitors include.

6. energy storage device (1) according to one of claims 1 to 5, wherein the

Coupling elements (7a; ...; 7d), the energy storage cell branch coupling elements (17c) and / or the bypass branch coupling elements (17a) comprise power semiconductor switches.

The energy storage device (1) according to claim 6, wherein the power semiconductor switches comprise insulated gate bipolar transistors, IGBTs, junction field effect transistors, JFETs, or metal oxide semiconductor field effect transistors, MOSFETs.

8. Energy storage device (1) according to one of claims 1 to 7, wherein the

Energy storage device (1) with a regenerative energy source, e.g. a photovoltaic module, and / or a local or central power grid, e.g.

House connection of the energy supplier, is coupled.

9. System (100), with:

an n-phase electric machine (2), where n> 1;

an energy storage device (1) according to one of claims 1 to 7; and n phase lines (2a, 2b, 2c), each having one of the output terminals (1a, 1b,

1 c) of the energy storage device (1) with in each case one of n phase terminals of the n-phase electric machine (2) couple.

10. System (100) according to claim 9, wherein the n-phase electric machine (2) is a synchronous machine, an asynchronous machine or a switched one

Reluctance machine includes.