AU2009268165B2

AU2009268165B2 - High-speed circuit breaker for a high-performance battery in an isolated direct current network

Info

Publication number: AU2009268165B2
Application number: AU2009268165A
Authority: AU
Inventors: Gerd Ahlf; Walter Marx; Oskar Risius; Andreas Schuldt; Hans-Jurgen Tolle
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2008-07-09
Filing date: 2009-06-26
Publication date: 2013-03-21
Anticipated expiration: 2029-06-26
Also published as: RU2500062C2; EP2297830A2; DE102008053074A1; KR101653847B1; RU2011104498A; WO2010003835A2; KR20110039242A; EP2297830B1; ES2662318T3; AU2009268165A1; TR201802364T4; WO2010003835A3

Abstract

The invention relates to a high-speed circuit breaker (1) for a high-performance battery (2) in an isolated direct current network (3), in particular a submarine direct current network. The high-performance battery (2) comprises several battery modules (4) connected in parallel, each having one branch (5) or several (5) branches of high-performance battery cells (6), said branch or each of said branches (5) having the network voltage of the isolated direct current network (2). The circuit breaker has a respective switching unit (12) for each of the battery modules (4), said unit having a parallel circuit (8) consisting of a biased diode (9) that allows the passage of the charging current (4) of the battery modules and of a biased power semiconductor switch (10) that allows the passage of the discharging current. The parallel circuit (8) is located in a connecting conductor (4) for the isolated direct current network (3) and the switched state of the power semiconductor switch (10) can be controlled by a monitoring and control unit (11), said unit (11) being designed in such a way that in order to disconnect a discharging current in the connecting conductor (7) it interrupts the charging current flowing in the connecting conductor (7) by switching the power semiconductor switch to a non-conductive state (10).

Description

1 Description High-speed switching device for a high-power battery in a stand-alone direct-current power supply system The invention relates to a high-speed switching device for a high-power battery in a stand-alone direct-current power supply system, in particular a submarine direct-current power supply system,. The invention also relates to a stand-alone direct-current power supply system. BACKGROUND High-power batteries which are being developed at the moment, for example lithium-ion battery cells, lithium-polymer cells, lithium-iron-phosphate battery cells, lithium-titanate battery cells and combinations of them are distinguished, in comparison to conventional batteries such as lead-acid batteries, by considerably shorter charging and discharge times, and by a considerable increase in the short-time discharge current. On the other hand, the extraordinarily high perspective short- circuit currents which, for example, may be 20 kA for a battery section and up to 500 kA per battery are considered to be problematic for their use in a stand-alone direct-current power supply system in the form of a large installation, for example for a power supply for use within a power station, or in a submarine direct-current power supply system. In a stand-alone direct-current power supply system, a battery installation normally has a switching device for switching the battery currents and for limiting the short-circuit currents. By way of example, EP 1 641 066 A2 and WO 2008/055493 Al disclose a direct-current power supply having a high-power battery with a switching device such as this. In this case, a high-power battery in a stand-alone direct- current power supply system normally has a plurality of parallel-connected battery modules, each having one section or a plurality of parallel-connected sections of series-connected 7017614V1 2 high-power battery cells, wherein the section or each of the sections is at the power supply system voltage of the stand- alone direct-current power supply system. Against this background, a need exists to specify a switching device for a high-power battery in a stand-alone direct-current power supply system, in particular a submarine direct-current power supply system, by means of which discharge currents from the high-power battery can be switched off particularly quickly. The present disclosure provides on the one hand, by a high-speed switching device having the features of patent claim 1, and on the other hand by a high-speed switching device having the features of patent claim 4. A stand-alone direct-current power supply system having high-speed switching device is the subject matter of patent claim 14. Advantageous refinements are the subject matter of the respective dependent claims. A first aspect of the present disclosure provides a high-speed switching device for a high-power battery in a stand-alone direct-current power supply system, wherein the high-power battery has a plurality of parallel- connected battery modules each having one section or a plurality of parallel-connected sections of series-connected high-power battery cells, wherein the section or each of the sections is at the same power supply system voltage as the stand-alone direct current power supply system wherein the high-speed switching device has a plurality of high speed switching units which are connected in connecting conductors of the battery modules to the stand-alone direct-current power supply system, wherein the high-speed switching units each comprise a diode, which is forward-biased for the charging current of the battery module, and a power semiconductor switch, which is connected such that the discharge current passes through the power semiconductor switch, connected in parallel, the switching state of the power semiconductor switch can be controlled by a monitoring and control device, and wherein the monitoring and control device is designed to interrupt the discharge current flowing in the connecting conductor by switching the power semiconductor switch to a switched-off state, in order to switch off a discharge current from the battery module in the connecting conductor. In the high-speed switching device of the first aspect, when the battery module is being charged, the charging current flows via the diode into the battery and, when the battery module is being discharged, the discharge current flows via the semiconductor switch. The discharge current can be interrupted in a considerably shorter time, in comparison to a conventional circuit breaker, by appropriate operation of the semiconductor switch by the monitoring and control apparatus. 7017614V1 2a According to one particularly advantageous refinement, wherein the monitoring and control device is designed such that it quickly detects a short-circuit current in the connecting conductor, and interrupts the short-circuit current by switching the power semiconductor switch to a switched-off state. The high-speed switching device allows the discharge current to be interrupted in a considerably shorter time in comparison to a conventional circuit breaker, and in the process, allows the short-circuit current of the individual battery module and, as a consequence of this, the total short-circuit current of all the battery modules in the battery as well, to be limited to non-critical values such that there is no need for further current-limiting and switching-off 7017614V1 3 means for the total short circuit currents. In order to suppress switching overvoltages on the power semiconductor, a diode is preferably connected in parallel with the parallel circuit, and is arranged in a conductor path which connects a connecting conductor which is connected to the positive pole of the battery module, and a connecting conductor, which is connected to the negative pole of the battery module. A second aspect of the present disclosure provides a high-speed switching device for a high power battery in a stand-alone direct-current power supply system, wherein the high-power battery has a plurality of parallel-connected battery modules each having one section or a plurality of parallel-connected sections of series-connected high-power battery cells, wherein the section or each of the sections is at the same power supply system voltage as the stand alone direct-current power supply system wherein the high-speed switching device as a plurality of high-speed switching units which are connected in connecting conductors of the battery modules to the stand-alone direct-current power supply system, wherein the high-speed switching units each have a parallel circuit comprising a mechanical switch, through which the charging current and the discharge current of the battery module as, and at least one power semiconductor switch , which is connected such that the discharge current passes therethrough, wherein the switching states of the mechanical switch and of the power semiconductor switch can be controlled by a monitoring and control device, and wherein the monitoring and control device is designed to commutate a current flowing through the mechanical switch onto the semiconductor switch by opening the mechanical switch in order to switch off a discharge current in the connecting conductor, and then interrupts the discharge current flowing in the connecting conductor by switching the semiconductor switch to the switched-off state. In the case of the high-speed switching device of the second aspect, when the battery module is being charged, the charging current flows via the mechanical switch. In addition, when the battery is being discharged, the entire discharge current, or at least a portion of the discharge current, flows via the mechanical switch. Only when the discharge current is switched off by opening the mechanical switch is the discharge current commutated completely onto the semiconductor switch, and is then switched off by the semiconductor switch. During normal operation, the current is therefore carried essentially via the mechanical switch. This makes it possible to avoid losses, since the losses of a mechanical switch are considerably less than those of a semiconductor component. The time between the opening of the mechanical switch and the semiconductor switch being switched off can in this case be chosen such that, when the semiconductor switch is switched off, the distance between the contacts of the mechanical switch is sufficiently great that the arc between the contacts has already been 7017614V1 3a reduced such that no new arc is struck between the contacts when the semiconductor switch is switched off. According to one particularly advantageous refinement, the monitoring and control device is designed such that it quickly detects a short-circuit current in the connecting conductor, and interrupts the short-circuit current by switching the power semiconductor switch to a switched off state. The high-speed switching device therefore allows the discharge current to be interrupted in a considerably shorter time 7017614V1 4 than with a conventional circuit breaker, and in the process allows the short-circuit current of the individual battery module, and, as a consequence of this, also the total short- circuit current of all the battery modules in the battery, to be limited to non-critical values, such that there is no need for further current-limiting and switching-off means for the total short-circuit currents. In this case, the semiconductor switch may already be in a switched-on state when the mechanical switch is opened, that is to say that a current flows both via the mechanical switch and via the semiconductor switch during normal discharge operation. However, it is preferable for the semiconductor switch to be in a switched-off state when the mechanical switch is opened, and for the monitoring and control device to be designed such that it switches the semiconductor switch to a switched-on state when the mechanical switch is opened. Therefore, current flows via the semiconductor switch only in order to switch off the discharge current, thus making it possible to minimize losses. The mechanical switch is preferably in the form of a vacuum switch. By way of example, the contacts of the mechanical switch can be opened rapidly by using the force of an electrodynamic drive, which operates on the principle of the Thomson effect, to open the contacts. An electrical resistor, preferably a varistor, is preferably connected in parallel with the semiconductor switch, for absorbing electrical energy and for limiting overvoltages which occur on the semiconductor switch, after the semiconductor switch has been switched to the switched-off state. 7017614V1 5 By way of example, GTOs, IGBTs or IGCTs can be used as power semiconductor switches both for the solution of the first aspect and for the solution of the second aspect. In this case, it is possible to achieve switching-off times for short-circuit currents of less than 10 microseconds, while only about 3 to 5 ms is possible using conventional high-speed switches. This makes it possible to limit the total short-circuit currents to safe values, which would be completely impossible with conventional protection and switching members in some stand alone direct-current power supply systems, in particular in submarine direct-current power supply systems, using conventionally available switching and protection members (for example compact switches) as switches for the individual sections because the total short-circuit currents per battery would then be so great that additional current limiting/switching off would be necessary. The current involved with such conventional current limiting/switching off for the total short-circuit current (for example special fuses), of about 200 kA for example, is, however, still considerably greater than the maximum-permissible short-circuit currents of the previous installations and the available switching and protection members. However, the switching device according to the invention makes it possible to cope with the total short- circuit currents of a battery using the conventional switching and protection members. Preferably, each of the battery modules in each case has only a single section of series connected high-power energy-storage battery cells, that is to say the switching device in each case has one switching unit for each individual one of the sections. In the event of a short circuit, this makes it possible to limit the total short-circuit currents of the entire battery to particularly low values, which can thus be coped with particularly reliably. Preferably, the connecting conductor with the switching unit connects the positive pole of the battery module to the direct- current power supply system connects, that is to say the switching unit is connected between the positive pole of the battery module and the direct-current power supply system. A mechanical switch, in particular an isolating switch, can respectively be arranged in a connecting conductor 7017614V1 6 which connects the positive pole of the battery module to the direct-current power supply system, and in a connecting conductor which connects the negative pole of the battery module to the direct-current power supply system, in order to disconnect the battery module from the direct-current power supply system in a floating manner. This may also be a single switch with a plurality of switching contact pairs, in which case, for example, one contact pair is arranged in one connecting conductor, and the other contact pair is arranged in the other connecting conductor. The battery cells advantageously consist of lithium-ion battery cells, lithium-polymer battery cells, lithium-iron-phosphate battery cells, lithium-titanate battery cells or combinations thereof. When using a high-speed switching device, for example a high- speed switching device according to the invention as described above, in a stand-alone direct-current power supply system, in particular a submarine direct-current power supply system, having at least one electrical load, a high-power battery as explained above for supplying electrical power to the electrical load and having a protection member, which is connected between the electrical load and the high-power battery, for the load, in particular a fuse, the currents in the battery modules in the event of a short circuit can be switched off and limited to values which can be coped with safely as total short-circuit currents by the stand-alone direct-current power supply system. The battery modules can be switched off safely even in the event of a fault, for example in the event of an overload. If each high-speed switching device for each of the battery modules were to have a high-speed switching unit and if the high-speed switching units were to trip more quickly than the downstream protection member for the load in the event of a short circuit on the load, then a short circuit on the load would not lead to tripping of the protection member. There would therefore be no selectivity between the high-speed switching units and the protection member. Since the protection member does not trip, the short-circuit connection location would remain unknown. Subsequent connection 7017614V1 7 of the battery modules would once again lead to a short circuit, and thus to the battery modules being switched off. Overall, this can lead to a permanent black-out of the entire stand alone direct-current power supply system. By way of example, in the conditions which occur in submarine direct-current power supply systems, the tripping time of the high-speed switching units according to the invention can be in the region of microseconds, while it may be in the region of milliseconds in the case of protection members, and particularly fuses. A third aspect of the present disclosure provides a stand-alone direct-current power supply system comprising an electrical load, a high-power battery for supplying electrical power to the electrical load, wherein the high-power battery has a plurality of parallel-connected battery modules each having one section or a plurality of parallel-connected sections of series connected high-power battery cells , wherein the or each of the sections is at the same power supply system voltage as the stand-alone direct-current power supply system , a protection member, which is connected between the electrical load and the high-power battery, for the load, characterized by a high-speed switching device, as claimed in one of the preceding claims, having high-speed switching units for interruption of short-circuit currents in the battery modules, wherein the high-speed switching units are connected between the battery modules and the protection member, and wherein no high-speed switching unit is connected between at least one of the battery modules and the protection member. Therefore, no high-speed switching unit is deliberately connected between at least one of the battery modules and the protection member in the stand-alone direct-current power supply systemof the third aspect. A short-circuit current is therefore deliberately not switched off in this at least one battery module. The short-circuit current or currents which is or are not switched off then leads or lead to tripping of the downstream protection member for the load, that is to say to melting of the fuse, in the case of a fuse. This reliably disconnects the load from the direct current power supply system. The battery modules which have been switched off can then be automatically reconnected to the direct-current power supply system by the high-speed switching units. When a high-speed switching unit is connected in between, a current flow from a battery module to the load can lead to a voltage drop across the high-speed switching unit. This means that battery modules which are connected to the load via an intermediatehigh-speed switching unit and battery modules which are connected to the load without an intermediate high-speed switching unit discharge differently. A compensation unit for compensating for the current/voltage characteristic of a high 7017614V1 7a speed switching unit is therefore connected in the electrical connection between the at least one battery module and the protection member, in which electrical connection no high-speed switching unit is connected, in order to discharge all the battery modules uniformly. 7017614V1 8 The compensation unit 51 preferably has the same current/voltage characteristic as a high speed switching unit, at least in the region of the operating voltages and currents, and in this case at least for the discharge currents of the battery module 4a. In one physically particularly simple refinement, the compensation unit the compensation unit has a parallel circuit comprising a diode which is forward-biased for the charging current of the battery module, and a diode which is forward- biased for the discharge current. In order to ensure that the power supply system is available again quickly after a short circuit on the load, the high-speed switching units can be designed such that they detect the voltage in the power supply system after the battery modules have been disconnected from the direct current power supply system because of short-circuit currents, and automatically reconnect the battery modules to the direct-current power supply system after the voltage returns. BRIEF DESCRIPTION OF THE DRAWINGS The invention as well as advantageous refinements of the invention will be explained in more detail in the following text with reference to exemplary embodiments in the figures, in which: Figure 1 shows an outline illustration of a first stand-alone direct-current power supply system, Figure 2 shows a first example of the design of a battery module as shown in Figure 1, Figure 3 shows a second example of the design of a battery module as shown in Figure 1, Figure 4 shows an example of the design of a switching unit as shown in Figure 1, Figure 5 shows an outline illustration of a second stand-alone direct-current power supply system, Figure 6 shows an example of the design of a switching unit as shown in Figure 1, 7017614V1 9 Figure 7 shows an outline illustration of a submarine direct- current power supply system based on a stand-alone direct-current power supply system as shown in Figure 1, Figure 8 shows an outline illustration of a submarine direct-current power supply system based on direct-current power supply system a stand-alone as shown in Figure 5, Figure 9 shows the stand-alone direct-current power supply systems as shown in Figure 1 with a superordinate control device, and Figure 10 shows the stand-alone direct-current power supply systems as shown in Figure 5 with a superordinate control device, Figure 11 shows the stand-alone direct-current power supply system as shown in Figure 1 with selective tripping, Figure 12 shows one preferred refinement of a compensation module as shown in Figure 11, Figure 13 shows a simplified illustration of a submarine direct-current power supply system with switching and compensation units, and Figure 14 shows one preferred refinement of the switching and compensation units as shown in Figure 13. DETAILED DESCRIPTION Figure 1 shows an outline illustration of a first stand-alone direct-current power supply system 3 according to the invention which has a high-power battery 2 for storage of electrical energy, a generator G for production of electrical power, and a motor M as a power load. The battery 2 has a plurality of parallel-connected battery modules 4, each having one section or a plurality of parallel-connected sections of series- connected high-power battery cells, wherein the section or each of the sections is at the same power supply system voltage as the stand-alone direct current power supply system. By way of example, as is illustrated in Figure 2, a battery module may have three parallel connected sections 5 of battery cells 6, which are in each case connected in series. However, as illustrated in Figure 3, a battery module 4 preferably has only a single section 5 of series connected battery cells 6. 7017614V1 PCT/EP2009/058032 - 10 2008P12748WOAU By way of example, the battery cells 6 consist of lithium-ion battery cells, lithium-polymer battery cells, lithium-iron phosphate battery cells, lithium-titanate battery cells or combinations thereof. A high-speed switching device 1 in each case has a high-speed switching unit 12 for each of the battery modules 4, which - as illustrated in Figure 4 - has a parallel circuit 8 comprising a diode 9 which is forward-biased for the charging current of the battery module, and a power semiconductor switch, which is connected such that the discharge current passes through it, connected in parallel. This parallel circuit 8 is arranged in a connecting conductor 7 from the battery module 4 to the direct current power supply system 3. The switching state of the power semiconductor switch 10 can be controlled by a monitoring and control device 11, wherein the monitoring and control device 11 is designed such that it interrupts the discharge current flowing in the connecting conductor 7 by switching the power semiconductor switch 10 to a switched-off state, in order to switch off a discharge current in the connecting conductor 7. In this case, the monitoring and control device 11 is designed such that it quickly detects a short-circuit current in the connecting conductor 7, and interrupts the short-circuit current by switching the power semiconductor switch 10 to a switched-off state. For this purpose, the monitoring and control device 11 detects the discharge current in the connecting conductor 7 via a line 16, and controls the semiconductor switch 10 via a control line 17. The monitoring and control device 11 therefore identifies a PCT/EP2009/058032 - 10a 2008P12748WOAU short circuit in the power supply system, and switches off the controllable semiconductor within microseconds, as a result of which the short-circuit current in the module 4, and therefore also the total short-circuit current in all the modules 4, is limited to a safe value, and is switched off.

PCT/EP2009/058032 _ 11 _ 2008P12748WOAU The connecting conductor 7 in which the switching unit 12 or the parallel circuit 8 is arranged connects the positive pole (+) of the battery module 4 to the direct-current power supply system 3. A diode 13, which is connected in parallel with the parallel circuit 8 of a switching unit 12, and is arranged in a conductor path 19 which connects the connecting conductor 7, which is connected to the positive pole (+) of a battery module 4, and a connecting conductor 14, which is connected to the negative pole (-) of the battery module 4, is used to suppress switching overvoltages on the power semiconductor 10. In order to make it possible to switch off a battery module 4 or a section 5 in the event of a faulty semiconductor, and for galvanic isolation of a battery module 4 or section 5 from the power supply system 3, a respective mechanical switch 15 or 25, for example an isolating switch, is arranged in the connecting conductor 7 which connects the positive pole (+) of the battery module 4 to the direct-current power supply system 3, and in the connecting conductor 14 which connects the negative pole (-) of the battery module 4 to the direct-current power supply system 3. The respective switch 15 or 25 can be operated manually, or if required remotely. The mechanical switch 15 in the connecting conductor 7 is in this case arranged between the switching unit 12 and the direct-current power supply system 3. A stand-alone direct-current power supply system as shown in Figure 5 differs from the stand-alone direct-current power supply system as shown in Figure 1 in that the diodes 13 are omitted from the switching device 1, in that the switching device 1 has monitoring and control devices 31 instead of the monitoring and control devices 11, and in that it has switching units 32, as illustrated in more detail in Figure 6, instead of PCT/EP2009/058032 - 11a 2008P12748WOAU the switching units 12. The switching units 32 each have a parallel circuit 28 comprising a mechanical switch 29, through which the charging current and the discharge current of the battery module 4 can flow, and PCT/EP2009/058032 - 12 2008P12748WOAU at least one power semiconductor switch 30 which is connected such that the discharge current can flow through it. The parallel circuit 28 of the switching unit 32 is in this case also arranged in the connecting conductor 7 of the battery module 4 to the direct-current power supply system 3. The switching states of the mechanical switch 29 and of the power semiconductor switch 30 can be controlled by a monitoring and control device 31, wherein the monitoring and control device 31 is designed such that it commutates a current flowing through the mechanical switch onto the semiconductor switch 30 by opening the mechanical switch 29 in order to switch off a discharge current in the connecting conductor 7, and then interrupts the discharge current flowing in the connecting conductor by switching the semiconductor switch 30 to a switched-off state. In this case, the monitoring and control device is designed such that it quickly detects a short-circuit current in the connecting conductor 7, and interrupts the short-circuit current by switching the power semiconductor switch 30 to a switched-off state. In this case, the monitoring and control device 31 is also connected via a control line 18 to the mechanical switch 29, in order to control the switching state of the mechanical switch 29. The semiconductor switch 30 may already be in a switched-on state when the mechanical switch 29 is opened. However, in order to avoid losses, the semiconductor switch 30 is in a switched-off state when the battery module 4 is discharging, that is to say even when the mechanical switch 29 is opened, and the monitoring and control device is designed such that it switches the semiconductor switch 30 to a switched-on state PCT/EP2009/058032 - 12a 2008P12748WOAU when the mechanical switch 29 is opened.

PCT/EP2009/058032 - 13 2008P12748WOAU The mechanical switch 29 is preferably in the form of a vacuum switch. In addition, a high-speed switching unit 32 also has a varistor 34, which is connected in parallel with the semiconductor switch 30, for absorbing electrical energy and for limiting overvoltages which occur on the semiconductor switch 30, after the semiconductor switch 30 has been switched to the switched-off state. A submarine direct-current power supply system 40 as shown in Figure 7 has two power supply subsystems 41, which can be coupled to one another via a power supply system coupling 42. Each of the power supply subsystems 41 each has a battery 2, as shown in Figure 1, and a switching device 1. Each of the battery modules 4 has one and only one section 5 of series connected battery cells, as a result of which the switching device 1 for a battery 1 in each case has one switching unit 12, one control and monitoring device 11 and one diode 13 for each of the sections 5. Typically, each of the sections has a rated voltage of 900 V, and a battery comprises about 20 parallel-connected sections. The switches 15 are preferably in the form of a mechanical isolating apparatus, and are used for potential isolation of the respective battery module 4 or section 5 from the respective power supply subsystem 41. The switches 25 are preferably in the form of circuit breakers (for example compact switches) and are used on the one hand for potential isolation of the respective battery module 4 or section 5 from the respective power supply subsystem 41, and on the other hand for short-circuit disconnection in the event of PCT/EP2009/058032 - 13a 2008P12748WOAU a failure of the switching unit 12 associated with the respective battery module 4 or section 5.

PCT/EP2009/058032 - 14 2008P12748WOAU In addition, each of the batteries 2 can be disconnected from the respective power supply subsystem 41 via mechanical switches 35 which are connected in series with the batteries 2. A submarine direct-current power supply system 40 as shown in Figure 8 differs from the submarine direct-current power supply system 40 as shown in Figure 7 in that the switching device 1 is based on the solution illustrated in Figure 5. Figure 9 and Figure 10 show the stand-alone direct-current power supply system as shown in Figure 1 and Figure 5, respectively, in each case with an additional superordinate control device 50, which is connected via lines 51 to the respective monitoring and control devices 11 and 31 and, via these lines 51, transmits switch-off commands for switching off discharge currents for operational purposes, by the switching units 12 and 32 to the monitoring and control devices 11 and 31, respectively, and receives responses from the respective monitoring and control devices 11 and 31. If the discharge currents which occur during operation are also switched off by means of the semiconductor switches, physically small versions can be chosen for the mechanical switches. The invention allows simpler integration of high-power batteries in new installations, and retrofits to existing installations. A control voltage for the monitoring and control devices 11, 31 and switching units 12, 32 can be provided by a dedicated supply from the associated battery module 4, or by a supply which is independent thereof (for example back-up battery, PCT/EP2009/058032 - 14a 2008P12748WOAU etc.). Instead of one monitoring and control devices 11, 31 in each case, it is also possible to provide a single, superordinate monitoring and control device.

PCT/EP2009/058032 - 15 2008P12748WOAU After limiting and switching off a short circuit, a high-speed switching unit 12, 32 is ready to operate again immediately. However, the embodiment is advantageously designed, such that, if required, reconnection is permissible only after an acknowledgement (that is to say the cause of the fault has been rectified). In the event of a faulty semiconductor (for example as a result of a breakdown), the advantage of monitoring the fault is immediately evident, thus allowing measures to be taken (for example disconnection of the battery module or section) . If a short circuit were to occur at this moment, a downstream switching device (for battery switching device) will be able to cope with the short-circuit current of one or even a plurality of sections. The stand-alone direct-current power supply system 3 as shown in Figure 11 corresponds fundamentally to the stand-alone direct-current power supply system 3 shown in Figure 1, but with the load M now being connected to the direct-current power supply system 3 via a protection member in the form of a fuse 50. The high-speed switching units 12 are therefore connected between the fuse 50 and the battery modules 4. If the high-speed switching device 1 for each of the battery modules 4 were in each case to have a high-speed switching unit 12, and the high-speed switching units 12 were to trip more quickly than the downstream fuse 50 in the event of a short circuit on the load M, then a short-circuit on the load M would not lead to blowing of the fuse 50. For example, in the conditions which occur in submarine direct-current power supply systems, the tripping time of the high-speed switching units 12, 32 illustrated in Figures 4 and 6 may be in the region of microseconds while, the time for the fuse 50 to blow is in the PCT/EP2009/058032 - 15a 2008P12748WOAU millisecond range. This therefore means that there is no selectivity between the high-speed switching units 12 and the fuse 50. This can lead to a black-out of the entire stand-alone direct-current power supply system 3. In order to prevent this, no switching unit is deliberately connected between the battery module 4a and the fuse 50, or the load M, for one battery PCT/EP2009/058032 - 16 2008P12748WOAU module 4a. The short-circuit current for the battery module 4a is therefore deliberately not switched off in the event of a short circuit on the load M. The short-circuit current which is not switched off then leads to blowing, that is to say melting, of the fuse 50. This disconnects the load from the direct current power supply system 2. The battery modules 4 which have been switched off can then be automatically reconnected to the direct-current power supply system 2 by the high-speed switching units 12 of the switching device 1. A current flow from a battery module 4 to the load M normally leads to a voltage drop across the high-speed switching unit 12 connected between them, and therefore to different discharge rates from the battery modules 4, 4a which are connected to the load M with and without an intermediate high-speed switching unit 12. A compensation unit 51 for compensating for the current/voltage characteristic of the high-speed switching units 12 is therefore connected between the battery module 4a and the fuse 50, in this case in the connecting line 7 of the battery module 4a to the direct-current power supply system 3, in order to ensure that all the battery modules 4, 4a are discharged uniformly. The compensation unit 51 preferably has the same current/voltage characteristic as a high-speed switching unit in the region of the operating voltages and currents, at least for the discharge currents, of the battery module 4a. In one physically particularly simple refinement, which is shown in Figure 12, the compensation unit 51 has a parallel circuit 52 comprising a diode 53, which is forward-biased for the charging current of the battery module 4a, and a diode 54, which is forward-biased for the discharge current. When using a high-speed switching unit 12 as shown in Figure 4, a diode of the same type as that of the diode 9 for the high- PCT/EP2009/058032 - 16a 2008P12748WOAU speed switching unit 12 shown in Figure 4 is preferably used for the diode 53, as a result of which the diode 53 has the same current/voltage characteristic as the diode 9, which is PCT/EP2009/058032 - 17 2008P12748WOAU forward-biased for the charging current of the battery module 4 for the high-speed switching unit 12. The diode 54 is preferably chosen such that it has essentially the same current/voltage characteristic as the power semiconductor 10 of the high-speed switching unit 12 shown in Figure 4. In order to ensure that the power supply system is available again quickly after a short-circuit on the load, the high-speed switching units can be designed such that they detect the voltage in the direct-current power supply system 3 after the battery modules 4 have been disconnected from the direct current power supply system 2 because of a short circuit, and automatically reconnect the battery modules 4 to the direct current power supply system 3 after the voltage returns. Figure 13 shows a simplified illustration, for the forward conductor only (that is to say the conductor with the positive potential) of a submarine direct-current power supply system 60, which consists of two power supply subsystems 61, 62 which can be connected to one another via a power supply system coupling 63. A first load 64 can be supplied with electrical power only from the power supply subsystem 61, and for this purpose is connected to the power supply subsystem 61 via a fuse 50. A second load 65 can be supplied with electrical power from both power supply subsystems 61, 62, and is for this purpose connected to the two power supply subsystems 61, 62 via a respective fuse 50 and a diode 66 (for decoupling the two power supply subsystems 61, 62). Each of the two power supply subsystems 61, 62 in each case has a high-power battery 2, in each case with a plurality of PCT/EP2009/058032 - 17a 2008P12748WOAU parallel-connected battery modules 4, 4a, each having one section or a plurality of parallel-connected sections of series-connected high-power battery cells, wherein the section or each of the sections is at the same voltage as the power supply system 60.

PCT/EP2009/058032 - 18 2008P12748WOAU One high-speed switching device 1 is in each case used to interrupt short-circuit currents of the battery 1 in a respective power supply subsystem 61 or 62. The high-speed switching device 1 has a plurality of high-speed switching units 67 and a plurality of compensation units 51. By way of example, the high-speed switching units 12 shown in Figure 4 or the high-speed switching units 32 shown in Figure 6 may be used as high-speed switching units. However, in principle, it is also possible to use other refinements of the high-speed switching units 67. Each of the battery modules 4 is connected to the respective power supply subsystem 61, 62 via one and only one high-speed switching unit 67, which is in each case associated with it and is connected in series with it. One and only one high-speed switching unit 67 is therefore connected between a battery module 4 and a fuse 50 of the load 64 or of the load 65. The battery modules 4a are connected to the respective power supply subsystem 61, 62 via one and only one compensation unit 51, which is associated with it and is connected in series with it. One and only one compensation unit 51 is therefore connected between a battery module 4 and a fuse 50 of the load 64 or of the load 65. The high-speed switching units 67 have a tripping time which is shorter than the time for the downstream fuses 50 for the loads 64, 65 to blow. A short circuit on the load 64 therefore leads to the battery modules 4 of the battery 1 of the power supply subsystem 61 being switched off by their respective high-speed switching units 67. The short-circuit currents in the battery modules 4a lead to blowing of the fuse 50 for the load 64. The battery modules 4 can subsFquentl.y be reconnected to the power supply PCT/EP2009/058032 - 18a 2008P12748WOAU subsystem 61 automatically by the high-speed switching units 67. In this case, just the short-circuit current of a single battery module 4a is preferably sufficient to blow the fuse 50. Since two PCT/EP2009/058032 -9 _ 2008P12748WOAU battery modules 4a without a high-speed switching unit 67 are provided for each battery 1, this results in redundancy since this ensures that the fuse 50 will still blow even in the event of a failure of one of the two battery modules 4a. A short circuit on the load 65 leads to the battery modules 4 in the batteries 2 for both power supply subsystems 61, 62 being switched off by their respective high-speed switching units 67. The short-circuit currents in the battery modules 4a in both batteries 1 lead, however, to blow of both fuses 50 for the load 65. After this, the battery modules 4 in the two batteries 2 can be automatically reconnected to the two power supply subsystems 61, 62 by the high-speed switching units 67. Since there are two battery modules 4a without high-speed switching units 67 in each of the two batteries 1, this also provides redundancy here. If one of the two batteries 1 were to be operated with the battery modules 4a switched off, the two power supply subsystems 61, 62 would be coupled to one another via the power supply system coupling 63. Battery switches 68 in the form of circuit breakers are used for switching in each case one part of a battery 1 during operation. They are also used as back-up protection for the situation in which one or more upstream high-speed switching units 67 has or have failed. Battery module switches 69 in the form of compact circuit breakers are used for all-pole floating disconnection of a battery module 4 (for example for maintenance work on the respective battery module 4 or the associated high-speed switching unit 67). They are also used as back-up short-circuit protection for the associated high-speed switching unit 12. Battery module switches 70, which are likewise preferably in the form of compact circuit breakers, are used to disconnect a PCT/EP2009/058032 - 20 2008P12748WOAU battery module 4a in the event of a fault (for example in the event of an overload, overvoltage, etc.). Figure 14 shows a detailed view of one preferred refinement of a high-speed switching unit 67 and of a compensation unit 51 as shown in Figure 13. In this case, the high-speed switching unit 67 corresponds substantially to the high-speed switching unit 12 shown in Figure 4, and the compensation unit corresponds substantially to the compensation unit shown in Figure 12. In this case, the high-speed switching unit has a monitoring and control unit 71 and a power supply 72. A battery switching device 73 has battery switches 68 for switching of the respective battery element during operation.

Claims

1. A high-speed switching device for a high-power battery in a stand-alone direct-current power supply system, wherein the high-power battery has a plurality of parallel-connected battery modules each having one section or a plurality of parallel-connected sections of series-connected high-power battery cells, wherein the section or each of the sections is at the same power supply system voltage as the stand-alone direct-current power supply system wherein the high-speed switching device has a plurality of high-speed switching units which are connected in connecting conductors of the battery modules to the stand-alone direct-current power supply system, wherein the high-speed switching units each comprise a diode, which is forward-biased for the charging current of the battery module, and a power semiconductor switch, which is connected such that the discharge current passes through the power semiconductor switch, connected in parallel, the switching state of the power semiconductor switch can be controlled by a monitoring and control device, and wherein the monitoring and control device is designed to interrupt the discharge current flowing in the connecting conductor by switching the power semiconductor switch to a switched off state, in order to switch off a discharge current from the battery module in the connecting conductor.

2. The high-speed switching device as claimed in claim 1, wherin the monitoring and control device is designed to quickly detect a short-circuit current in the connecting conductor, and interrupts the short- circuit current by switching the power semiconductor switch to a switched off state.

3. The high-speed switching device as claimed in claim 1 or 2, further comprising a diode, which is connected in parallel with the parallel circuit, is arranged in a conductor path and connects a connecting conductor, which is connected to the positive pole of the battery module, and a connecting conductor, which is connected to the negative pole of the battery module.

4. A high-speed switching device for a high-power battery in a stand-alone direct-current power supply system, wherein the high-power battery has a plurality of parallel-connected battery modules, each having one section or a plurality of parallel-connected sections of series-connected high-power battery cells, wherein the section or each of the sections is at the same power supply system voltage as the stand-alone direct-current power supply system wherein 7005216 I 22 the high-speed switching device has a plurality of high-speed switching units which are connected in connecting conductors of the battery modules to the stand-alone direct-current power supply system , wherein the high-speed switching units each have a parallel circuit comprising a mechanical switch , through which the charging current and the discharge current of the battery module as, and at least one power semiconductor switch , which is connected such that the discharge current passes therethrough, wherein the switching states of the mechanical switch and of the power semiconductor switch can be controlled by a monitoring and control device, and wherein the monitoring and control device is designed to commutate a current flowing through the mechanical switch onto the semiconductor switch by opening the mechanical switch in order to switch off a discharge current in the connecting conductor, and then interrupts the discharge current flowing in the connecting conductor by switching the semiconductor switch to the switched-off state.

5. The high-speed switching device as claimed in claim 4, wherein the monitoring and control device is designed to quickly detect a short-circuit current in the connecting conductor, and interrupt the short-circuit current by switching the power semiconductor switch to a switched-off state.

6. The high-speed switching device as claimed in claim 4 or 5, wherein the semiconductor switch is in a switched-on state when the mechanical switch is opened.

7. The high-speed switching device as claimed in claim 4 or 5, wherein the semiconductor switch is in a switched-off state when the mechanical switch is opened, and the monitoring and control device is designed to switch the semiconductor switch to a switched-on state when the mechanical switch is opened.

8. The high-speed switching device as claimed in anyone of claims 4 to 7, wherein the mechanical switch is in the form of a vacuum switch.

9. The high-speed switching device as claimed in one of claims 4 to 8, further comprising an electrical resistor, which is connected in parallel with the semiconductor switch, for absorbing electrical energy and for limiting over voltages which occur on the semiconductor switch, after the semiconductor switch has been switched to the switched-off state.

10. The high-speed switching device as claimed in one of the preceding claims, wherein each 23 of the battery modules in each case has only a single section of series-connected high-power energy-storage battery cells.

11. The high-speed switching device as claimed in any one of the preceding claims, wherein the connecting conductor connects the positive pole of the battery module to the direct-current power supply system.

12. The high-speed switching device as claimed in any one of the preceding claims, wherein a mechanical switch, is respectively arranged in a connecting conductor which connects the positive pole of the battery module to the direct-current power supply system, and in a connecting conductor which connects the negative pole of the battery module to the direct current power supply system.

13. The high-speed switching device as claimed in any one of the preceding claims, wherein the battery cells consist of lithium-ion battery cells, lithium-polymer battery cells, lithium-iron phosphate battery cells, lithium-titanate battery cells or combinations thereof.

14. A stand-alone direct-current power supply system comprising an electrical load, a high power battery for supplying electrical power to the electrical load, wherein the high-power battery has a plurality of parallel-connected battery modules each having one section or a plurality of parallel-connected sections of series-connected high-power battery cells , wherein the or each of the sections is at the same power supply system voltage as the stand-alone direct-current power supply system , a protection member, which is connected between the electrical load and the high-power battery, for the load, , characterized by a high-speed switching device, as claimed in one of the preceding claims, having high-speed switching units for interruption of short-circuit currents in the battery modules, wherein the high-speed switching units are connected between the battery modulesand the protection member, and wherein no high-speed switching unit is connected between at least one of the battery modules and the protection member.

15. The stand-alone direct-current power supply system as claimed in claim 14, wherein a compensation unit for compensating for the characteristic of a high-speed switching unit a compensation current/voltage is connected in the electrical connection between the at least one battery module and the protection member, in which electrical connection no high-speed switching unit is connected, in order to discharge all the battery modules uniformly.

16. The stand-alone direct-current power supply system as claimed in claim 15, wherein the 24 compensation unit has a parallel circuit comprising a diode which is forward-biased for the charging current of the battery module, and a diode which is forward-biased for the discharge current.

17. The stand-alone direct-current power supply system as claimed in anyone of claims 14 to 16, wherein the high-speed switching units detect the voltage in the power supply system after the battery modules have been disconnected from the power supply system as a result of short circuit currents, and automatically reconnect the battery modules to the power supply system after the voltage returns.

18. A high-speed switching device as claimed in any one of the preceding claims, wherein the stamp-alone direct-current power supply system is a submarine direct-current power supply system.

19. A high-speed switching device as claimed in any one of the preceding claims, wherein the mechanical switch is an isolating switch.

20. The stand-alone direct-current power supply system according to any one of claims 14-17, wherein the load is a fuse.

21. The high-speed switching device as claimed in claim 9, wherein the semiconductor switch is a varistor. DATED this fifteenth Day of January, 2013 Siemens Aktiengesellschaft Patent Attorneys for the Applicant SPRUSON & FERGUSON