WO2019091824A1

WO2019091824A1 - Battery storage system

Info

Publication number: WO2019091824A1
Application number: PCT/EP2018/079684
Authority: WO
Inventors: Tim Müller; Lars FALLANT; Manfred Liebscher; Lars MADEMANN
Original assignee: Belectric Gmbh
Priority date: 2017-11-13
Filing date: 2018-10-30
Publication date: 2019-05-16
Also published as: DE102017011584A1

Abstract

A battery storage system (1) having at least one series-connected string (3, 4, 5), wherein at least one first storage module (6, 6', 6") and one second storage module (7, 7', 7") are provided in each series-connected string (3, 4, 5), which modules are electrically connected to each other in series, wherein the series-connected string (3, 4, 5) is electrically connected to an inverter (2), which is connected on the alternating voltage side to an AC network, wherein at least one symmetry resistance (14, 15) is connected in parallel at least to each storage module (6, 6', 6", 7, 7', 7") of the series-connected string (3, 4, 5).

Description

Battery storage system

The invention relates to a battery storage system having at least one series train, wherein in each series train at least a first memory module and a second memory module are provided, which are electrically connected in series with each other, wherein the

Serial train is electrically connected to a converter that is on its

AC side is connected to an AC mains.

From the prior art, a battery storage system for power plants, in particular for solar power plants is known, which has a plurality of memory modules. The memory modules can come from, among other things, the automotive sector. The battery storage system comprises several series trains, each with two

Memory modules are provided. The memory modules of a series train are electrically connected in series. In a large number of series production runs, the series trains are electrically connected in parallel with each other. The series strings are electrically connected to a converter, which on its AC side with a

AC power is connected. The battery storage system itself is operated with a DC system voltage.

The memory modules, which preferably originate from the automotive sector, have a plurality of components, such as semiconductor elements, in particular

Semiconductor switches, which can be described by an equivalent resistor. It has been shown that the equivalent resistances of the individual memory modules can vary greatly. Consequently, in a series train with two series connected

Memory modules to these different substitute resistances. As a result, the DC system voltage splits in the same proportion as the equivalent resistance.

A critical state is especially present when switching elements of the memory module, which are used for switching on and off of the memory module, are in the open state and applied to the series strand a nominal voltage. The (nominal) voltage applied to the series train mentioned above can already be parallel

connected series strands or be impressed by the inverter itself. If a partial voltage applied to a memory module now exceeds a permissible limit value of a memory module in the series train, this can result in damage to the memory module and / or the other memory modules or even the complete battery memory system arranged in the series train.

The invention is therefore based on the object to provide a battery storage system, which in a cost effective manner reliable and safe operation

guaranteed.

The object is solved by the patent claim 1, in particular by the

characterizing part of patent claim 1. It is provided that in each case at least one memory module of the series strand at least one symmetry resistor is connected in parallel. With the help of

Symmetry resistance, an overvoltage of the memory modules is advantageously prevented, whereby a safe and reliable battery storage system is provided. This arrangement ensures that the voltage applied to the memory module voltage below a predetermined limit, in particular a

Threshold voltage of the memory module remains. This prevents the

Memory modules are destroyed.

The battery storage system can be reliably put into operation when the respective memory module has at least two switching elements, wherein the first

Switching element behind a first terminal point, which has the positive potential, is arranged and the second switching element in front of a second negative terminal point, which has a negative potential, is arranged.

According to a preferred embodiment of the battery storage system can be provided that the respective memory module comprises a heating element and / or a measuring and / or load circuit and / or a semiconductor, in particular a semiconductor switch, which are preferably arranged in a closed metallic housing, wherein the respective memory module an equivalent resistance, in particular a

Klemmersatzwiderstand, which is formed by the resistors of the heating element and / or the measuring and / or load circuit and / or the semiconductor, in particular the semiconductor switch, when at least one switching element has an open state, in particular when the first switching element and the second switching element have an open state.

The dimensioning of the symmetry resistance is dependent on the

Type-specific properties of the memory module, in particular after

Replacement resistance of the memory module and as a function of the tolerances of the memory module.

For the battery storage system, it can be very beneficial if the one

Memory module associated with symmetry resistance of lower resistance than the

Memory module assigned equivalent resistance is formed. By this measure, it is possible that a total resistance of the memory module, which by the

Symmetry resistance and the equivalent resistance is formed by the

Symmetry resistance is affected.

The battery storage system can work safely and reliably if that

Battery storage system has a working voltage range of preferably 600V-840V and a memory module has a working voltage range of preferably 300- 420V, wherein the DC system voltage is preferably substantially twice as large is like a terminal voltage, which lies in the working voltage range of the memory module.

According to a further preferred embodiment of the battery storage system can be provided when the memory modules are designed as previously used memory modules and / or as first-life memory modules. Used memory modules are memory modules that have already been used in one or more other systems and may suffer from power loss, such as memory modules previously used in electric cars. First-life memory modules are memory modules that have not previously been used, and where essentially none

Power losses occur. The use of used memory modules has the advantage that they are available on the market at low cost. The first-life memory modules offer the advantage that the storage capacity is very high. So it can make sense

Form battery storage systems both with used memory modules, as well as with first-life memory modules. It could offer a ratio of 90/10, the use of 90% used memory modules and 10% First Life memory modules, or the use of 10% used memory modules and 90% First Life memory modules. Depending on the selection, a low-cost and / or highly efficient battery storage system can be provided.

According to a preferred embodiment of the battery storage system can be provided that all first and all second switching elements of the battery storage system are open when the inverter is inactive and the DC system voltage has 0V. In this case, the battery storage system is in a shutdown state.

According to a further preferred embodiment of the battery storage system can be provided that the first equivalent resistance of the first memory module is formed high-impedance or low-impedance than the second equivalent resistance of the second memory module of the respective series strand.

The operation for the user of the battery storage system can be advantageously simplified if the switching element of the battery storage system via a

Communication interface, which is arranged in or on the housing of the memory module, are switchable. The communication interface can be designed as a CAN bus or else as a wireless connection, such as W-Lan.

A safe start of the battery storage system can be ensured when take in operation of the battery storage system in a first step, a DC circuit is charged to a default voltage and thereafter by switching on the switching elements of the memory module, these are continuously switchable, the battery storage system only after the connection all series trains can be operated at full power. The DC circuit is the electrical connection of the series strands with each other at their respective

Plus poles and their respective negative poles and forms the connection to the inverter. In order to improve the performance of the battery storage system, it may be provided that in an arrangement of more than one series strand in the battery storage system, the individual series strands are interconnected in parallel.

The number of symmetry resistors can advantageously be reduced if at least one first memory module system and one second memory module system are connected in series with at least one first memory module being connected in parallel and / or at least in the first memory module system at least in the second

Memory module at least two second memory modules are connected in parallel to each other, wherein the first memory modules and / or to the second

Memory modules in each case at least one symmetry resistor is connected in parallel.

The battery system according to the invention will be described in more detail with reference to two exemplary embodiments. The figures show:

1 shows a circuit diagram of a battery storage system according to the invention according to a first embodiment, and

Figure 2 is a circuit diagram of a battery storage system according to the invention according to a second embodiment.

FIG. 1 shows a battery storage system 1, for example for a solar power plant. The battery storage system 1 may also be connected to other power plants, such as hydropower plants, wind power plants, and the like. The battery storage system 1 has a working voltage range of preferably 600V-840V and a memory module (6, 6 ', 6 ", 7, T, 7") has a working voltage range of preferably 300-420V, the DC system voltage preferably in

Essentially twice as large as a terminal voltage, which in the

Working voltage range of the memory module is located.

The present battery storage system 1 has a converter 2, which comprises a positive pole and a negative pole and is electrically connected via lines with at least three series strands 3, 4 and 5. The series strands 3, 4, 5 are interconnected in parallel, as can be seen from the figure. The inverter 2 is on his

AC side connected to an AC mains.

The series strands 3, 4, 5 each have two connected in series

Memory modules 6, 6 ', 6 ", 7, 7', 7" on.

In the following, the mode of operation of the first series train 3 will be described. The other series strands 4, 5 are substantially similar to the structure and function of the series strand 3. The memory modules 6, 7 of the series train 3 are preferably designed as high-voltage storage, which are used for example in the automotive industry in electric vehicles. These may be used memory modules, which were previously used in electric vehicles, but also so-called first-live memory modules that were not yet in use.

The memory modules 6, 7 are essentially the same in construction. For example, the memory module 6 of the first series strand 3 comprises a heating element and / or a measuring and / or load circuit and / or a semiconductor, in particular a semiconductor switch, which are preferably arranged in a closed metallic housing, the memory module 6 having an equivalent resistance 8, in particular a clamping replacement resistor, which is formed by the resistors of the heating element and / or the measuring and / or load circuit and / or the semiconductor, in particular of the semiconductor switch, when a first switching element 9 and a second switching element 10 have an open state. Alternatively, it would also be sufficient if at least one switching element 9 or 10 has an opened state. Therefore, the memory module 6 comprises the at least two switching elements 9, 10, wherein the first switching element 9 behind a first terminal point, which has the positive potential is disposed, and the second switching element 10 in front of a second negative terminal point, which has a negative potential is disposed ,

Accordingly, the second memory module 7 also includes an equivalent resistor 11, a first switching element 12 and a second switching element 13. The switching elements 9, 10, 12, 13 are switchable via a communication interface, which is arranged in or on the housing of the memory module 6 and 7, respectively ,

Furthermore, each storage module 6, 7 of the series strand 3 is one each

Symmetry resistance 14, 15 connected in parallel. Basically, in the first memory module 6, the symmetry resistor 14 has a lower impedance than the equivalent resistance 8 and in the second memory module 7 the symmetrical resistor 15 has a lower impedance than the equivalent resistor 11. Furthermore, in the present exemplary embodiment, the first equivalent resistance 8 of the first memory module 6 is higher-impedance or lower-resistance than the second one

Substitute resistor 11 of the second memory module 7 of the series strand 3 is formed. The resistance values of the equivalent resistors 8 and 11 are in most cases unequal, since this with the construction and the nature of the memory modules 6, 7 and their

Manufacturing tolerances related. The replacement resistors 8, 11 are not to be regarded as static, but can, in particular at startup of the

Change battery storage system 1. In particular, the resistance values of the semiconductors can vary considerably in the memory modules 6, 7.

The operation of the battery storage system 1 will be described below. In the switched-off state of the battery storage system 1, all the switching elements of the battery storage system 1, in particular the switching elements 9, 10, 12, 13 in an open state and the inverter 2 is inactive, wherein the DC system voltage is then OV.

When starting the battery storage system 1, a DC system voltage of

for example 800V. As described above, the equivalent resistors 8 and 11 have different resistance values, in particular the equivalent resistance 8 is smaller, or even smaller, than the equivalent resistance 11. Without the symmetry resistors 14, 15, it could then happen that a voltage of, for example 600V is formed and the memory module 7, for example, a voltage of 200V is formed when the DC system voltage is 800V. For example, if the allowed

Limit voltage of the memory module 6 is 550V, then a voltage applied by 600V could lead to damage of the memory modules 6 and possibly 7.

In the battery storage system 1 according to the invention, however, provide the

Symmetry resistors 14, 15 for which, after detection and measurement of the respective equivalent resistors 8, 11 have been dimensioned accordingly, that the voltage drop U6, U7 to the memory modules 6, 7, in particular to the equivalent resistors 8, 11 is preferably in the range of the desired 400V. By the arrangement of

dimensioned symmetry resistors 14, 15 is advantageously ensured that when starting the battery storage system 1 damage to the memory modules 6, 7 and possibly further memory modules is prevented.

After charging the individual series strands 3, 4, 5 are on the

Communication interface the individual memory modules on their respective

Switching elements, in particular in the memory modules 6, 7 via their respective

Switching elements 9,10 and 12, 13 turned on. When all series 3, 4, 5 are switched on, the battery storage system 1 is ready. In operation, depending on the specification, the memory modules 6, 6 ', 6 ", 7, 7', 7", in particular the memory modules 6, 7 loaded or unloaded or remain in the idle state. When shutting down the battery storage system 1, the power supply is stopped, the switching elements of all memory modules open, the inverter 2 then the series strands 3, 4, 5 discharges.

It should be noted that as indicated in the figure by the dotted lines, a plurality of series trains behind the series strand 5 can be arranged.

It is also conceivable that the symmetry resistors are designed as variable resistors. These can preferably be used in measurements of the battery storage system 1.

For reasons of simplification, a few reference signs in the series strands 4, 5 have been dispensed with. As already mentioned, the series strands have a substantially identical structure. The series strands 3, 4, 5, in particular with regard to

Resistance values of the equivalent resistors differ because the different ones

Memory modules, in particular their individual components have tolerances. In the figure 2 is a second embodiment of the invention

Battery storage system 1 visualized. In FIG. 2, the storage well 6, 6 ', 6 "form the first storage module system 16 and the second storage modules 7, 7', 7" form the second

Memory Module System 17. The memory modules 6, 6 ', 6 "and 7, 7', 7" are connected in parallel in their respective memory module systems 16, 17. The number of

Memory modules in a memory module system 16, 17 can be selected arbitrarily high. Thus, it is also conceivable that in the first memory module system 16, three memory modules 6, 6 ', 6 "and in the second memory module system 17, a single memory module 7 or even a plurality of memory modules arranged.

As in the first exemplary embodiment, at least one symmetry resistor 14 or 15 is connected in parallel to at least each memory module 6, 6 ', 6 ", 7, 7', 7" of the series strand 3. Compared to the first embodiment, however, the number of

Symmetry resistors 14, 15 per memory module 6, 6 ', 6 ", 7, 7', 7" are reduced, because a plurality of memory modules 6, 6 ', 6 ", 7, 7', 7" are connected in parallel. It is likewise conceivable to use further series trains in the battery storage module 1 according to FIG. 2

to arrange, which have a similar or the same structure as the first series strand. 3

Claims

claims

1. Battery storage system (1) with at least one series train (3, 4, 5), wherein in each series train (3, 4, 5) at least a first memory module (6, 6 ', 6 ") and a second memory module (7, 7 ', 7 ") are provided, which are electrically connected in series with each other, wherein the series train (3, 4, 5) is electrically connected to an inverter (2), which is connected on its AC side to an AC mains, characterized in that at least to each memory module (6, 6 ', 6 ", 7, 7', 7") of the series strand (3, 4, 5) in each case at least one symmetry resistor (14, 15) is connected in parallel.

2. Battery storage system (1) according to claim 1, characterized in that the

respective memory module (6, 6 ', 6 ", 7, 7', 7") at least two switching elements (9, 10, 12, 13), wherein the first switching element (9, 12) behind a first

Clamping point, which has the positive potential, is arranged, and the second switching element (10, 13) before a second negative terminal point, which has a negative potential, is arranged.

3. Battery storage system (1) according to claim 1 or 2, characterized in that the respective memory module (6, 6 ', 6 ", 7, 7', 7") is a heating element and / or a measuring and / or load circuit and / or a semiconductor, in particular a

Semiconductor switch, which preferably in a closed

metallic housing are arranged, wherein the respective memory module (6, 6 ', 6 ", 7, 7', 7") an equivalent resistor (8, 11), in particular a

Klemmersatzwiderstand, which is formed by the resistors of the heating element and / or the measuring and / or load circuit and / or the semiconductor, in particular of the semiconductor switch, when at least one switching element (9, 10, 12, 13) has an open state, especially if the first

Switching element (9, 12) and the second switching element (10, 13) have an open state.

4. Battery storage system (1) at least one of claims 1 to 3, characterized

in that the symmetry resistance (14, 15) assigned to a memory module (6, 6 ', 6 ", 7, 7', 7") has a lower resistance than that of the memory module (6, 6 ', 6 ", 7, 7', 7 ") assigned equivalent resistance (8, 11) is formed.

5. Battery storage system (1) according to at least one of claims 1 to 4, characterized in that the battery storage system (1) has a working voltage range of preferably 600V-840V and a memory module (6, 6 ', 6 ", 7, 7', 7 ) has a working voltage range of preferably 300-420V, wherein the DC system voltage is preferably substantially twice as large as one

Terminal voltage, which lies in the working voltage range of the memory module.

6. Battery storage system (1) according to at least one of claims 1 to 5, characterized in that the memory modules (6, 6 ', 6 ", 7, 7', 7") as previously used memory modules and / or as first-life Memory modules are formed.

7. Battery storage system (1) according to at least one of claims 2 to 6, characterized in that all first (9, 12) and all second switching elements (10, 13) of the battery storage system (1) are open when the inverter (2) inactive is and the DC system voltage has 0V.

8. Battery storage system (1) according to at least one of claims 1 to 7, characterized in that the first equivalent resistance (8) of the first memory module (6) high impedance or low impedance than the second equivalent resistance (11) of the second memory module (7) of the respective series strand is trained.

9. battery storage system (1) according to at least one of claims 1 to 8, characterized in that take in operation of the battery storage system (1) in a first step, a DC circuit is charged to a default voltage and thereafter by turning on the switching elements (9 , 10, 12, 13) of the memory module (6, 7) are continuously connectable, wherein the battery storage system (l) only after the connection of all series strands (3, 4, 5) is operated at full power.

10. Battery storage system (1) according to at least one of claims 1 to 9, characterized in that the switching elements (9, 10, 12, 13) of the battery storage system (1) via a communication interface, which in or on the housing of the

Memory module (6, 6 ', 6 ", 7, 7', 7") is arranged, are switchable.

11. Battery storage system (1) according to at least one of claims 1 to 10, characterized in that in an arrangement of more than one series train in the battery storage system (1), the individual series strands (3, 4, 5) are interconnected in parallel.

12. Battery storage system (1) according to at least one of claims 1 to 11, characterized in that in at least one series train (3, 4, 5) at least a first memory module system (16) and a second memory module system (17) are arranged in series at least in the first memory module system (16) at least two first memory modules (6, 6 ', 6 ") are connected in parallel to each other and / or at least in the second

Memory module system (17) at least two second memory modules (7, 7 ', 7 ") are connected in parallel to each other, wherein the first memory modules (6, 6', 6") and / or to the second memory modules (7, T, 7 " ) at least one each

Symmetry resistor (14, 15) is connected in parallel.