Arrangement for protecting an energy storage system

Abstract

The invention relates to an arrangement for protecting an energy storage system (ESS) of a rail vehicle, the rail vehicle having an energy storage system (ESS), a fuse module (CFM), a DC link (GSZK) and a converter (UMR). The energy storage system (ESS) is connected to the DC link (GSZK) by the fuse module (CFM) such that direct current from the energy storage system (ESS) passes into the DC link (GSZK) via the fuse module (CFM). The DC link (GSZK) is connected, on the output side, to the converter (UMR) such that direct current from the DC link (GSZK) via the converter (UMR) can be used to drive the rail vehicle. The fuse module (CFM) has a number (z) of individually selectable fuses (CF1 to CFz) connected in parallel with one another. A first fuse (CF1 to CFz) of the fuse module (CFM) is selected and is switched in such a way that the direct current from the energy storage system (ESS) passes into the DC link (GSZK) via the first fuse (CF1 to CFz). In the event of a short circuit (KS) in the DC link (GSZK), the selected first fuse (CF1 to CFz) is switched in such a way that the flow of direct current through the first fuse is permanently interrupted. After the short circuit (KS) has ended, a second fuse (CF1 to CFz) of the fuse module (CFM) is selected and is switched in such a way that the direct current from the energy storage system (ESS) passes into the DC link (GSZK) through the second fuse (CF1 to CFz).

Description

[0001] Description

[0002] Arrangement for securing an energy storage system

[0003] The invention relates to an arrangement for securing an energy storage system of a rail vehicle.

[0004] Introduction and State of the Art

[0005] There are known rail vehicles that obtain traction energy from an energy storage system. This is shown by way of an example in FIG. 5 using a basic block diagram.

[0006] In this case, the energy storage system ESS is, for example, directly connected to an intermediate circuit GSZK, which is also referred to as a DC intermediate circuit or DC voltage intermediate circuit and is represented here by a (smoothing) capacitor Czk.

[0007] Between the intermediate circuit GSZK and the energy storage system ESS there is an inductance L, which is formed, for example, by the wiring or can also be part of a DC / DC converter.

[0008] The energy storage system ESS consists, for example, of a number of batteries, so that the energy storage system ESS feeds direct current into the intermediate circuit GSZK.

[0009] The intermediate circuit GSZK is connected on the output side to a converter UMR, which converts the direct current supplied to it into an alternating current, which then goes to a traction motor M to drive the rail vehicle.

[0010] The energy storage system ESS shown here has a number x of battery strings B1 to Bx connected in parallel to each other.

[0011] Each battery string B1 to Bx has one or two overcurrent protection elements Fn.x, where n from (1 ,2) represents double protection per battery string B1 to Bx. As a representative example, with x=1 in the first battery string B1, the positive terminal of a battery cell is connected to the intermediate circuit GSZK via a first fuse F1.1, which is designed as a fast-acting fuse.

[0012] Accordingly, a negative side of a battery cell of the first battery string B1 is connected to the intermediate circuit GSZK via a second fuse F2.1, which is also designed as a fast-acting fuse.

[0013] Here, a rail SCH traversed by the rail vehicle forms the ground potential as the reference potential of the block diagram, which is known as "hard grounding".

[0014] Preferably, the respective fuses Fnx are arranged or installed as close as possible to the battery cells of the battery strings B1 to Bx.

[0015] It is known that in a locomotive as a rail vehicle, only one central intermediate circuit is provided, which is used to supply all traction motors of the rail vehicle.

[0016] Typically, a so-called "crow-bar" or "short-circuiting device" is provided in the intermediate circuit, which generates a targeted short circuit in the converter in case of errors in the energy supply in the DC intermediate circuit.

[0017] In the event of a short circuit (KS) in the intermediate circuit, for example, the short-circuiting module simultaneously trips all fuses (Fnx) of the energy storage system (ESS). The resulting total failure of the energy storage system (ESS) renders the affected rail vehicle unavailable for operation, leading to costly and potentially dangerous operational delays or interruptions in rail traffic.

[0018] If conventional, mechanical DC quick-switches are used instead of fuses, a disadvantage arises: they switch slowly. With low inductances in the affected intermediate circuit, this leads to very high tripping overcurrents, and selectivity with the fuses of the energy storage system cannot be achieved. If selectivity with the fuses of the energy storage system is nevertheless required, the inductance must be significantly increased, resulting in increased weight, losses, and costs. At the same time, DC quick-switches themselves are large and heavy to handle.

[0019] If pyrotechnic disconnect devices, known as "pyro-fuses," are used instead of fusible links, a disadvantage arises: these disconnect devices are not resettable, thus preventing the desired rapid return of the rail vehicle to service. Furthermore, the use of explosives in pyrotechnic disconnection leads to unforeseeable consequential problems.

[0020] If semiconductor switches, also known as "e-fuses" or solid-state circuit breakers (SSCBs), are used instead of fuses, the disadvantages include increased costs and additional conduction losses. Further disadvantages are that these semiconductor switches may require active cooling and, due to their inductance, only allow limited energy absorption during the switching process.

[0021] From the patent application with the application number DE 10 2023 201 951.5 and the filing date 03.03.2023, a circuit for short-circuit protection of a traction battery system using selective semiconductor switches is known.

[0022] Task

[0023] The object of the invention described below is to provide an improved arrangement for safeguarding an energy storage device of a rail vehicle, taking into account the aforementioned disadvantages, in order to enable increased availability of the rail vehicle.

[0024] This problem is solved by the features of claim 1. Advantageous further developments are specified in the dependent claims.

[0025] Description of the invention

[0026] The invention relates to an arrangement for protecting an energy storage system of a rail vehicle. The rail vehicle comprises an energy storage system, a protection module, an intermediate circuit (referred to as a DC link or DC voltage link), and a converter.

[0027] The energy storage system is connected to the DC link via the fuse module, so that direct current from the energy storage system enters or is fed into the DC link via the fuse module.

[0028] The DC link is connected to the converter on the output side, so that direct current from the DC link can be used via the converter to drive the rail vehicle.

[0029] The fuse module has a number of individually selectable fuses connected in parallel (electrically to each other).

[0030] A first fuse of the fuse module is selected and connected in such a way that the direct current from the energy storage system enters the DC intermediate circuit exclusively via the first fuse.

[0031] In the event of a short circuit in the DC intermediate circuit, the selected first fuse is switched in such a way that the DC current flow through it is permanently interrupted or is permanently interrupted.

[0032] This means that the energy storage system is electrically isolated from the DC intermediate circuit.

[0033] After the short circuit has ended, a second fuse of the fuse module is selected and switched in such a way that the direct current from the energy storage system enters the DC intermediate circuit exclusively through the second fuse.

[0034] This procedure will be continued in the event of further short circuits.In essence, for n=1 to n=z: the fuse module contains z fuses to compensate for a total of z short-circuit events in the DC link; an nth fuse of the fuse module is selected and connected in such a way that the DC current from the energy storage system enters the DC link exclusively via the nth fuse; in the event of an nth short circuit in the DC link, the selected nth fuse is connected in such a way that the DC current flow through it is permanently interrupted; after the nth short circuit has ended, another (n+1)th fuse of the fuse module is selected and connected in such a way that the DC current from the energy storage system enters the DC link exclusively through this (n-1)th fuse, and so on, until in the event of z short circuit events all z fuses of the fuse module are permanently interrupted for a DC current flow.

[0035] In an advantageous further development, the energy storage system has internal fuses, which are preferably designed as fuse links.

[0036] The energy storage system has a number of battery strings connected in parallel, which are protected by one or two of the internal fuses.

[0037] In an advantageous further development, the fuses of the fuse module are selectively connected to the internal fuses of the energy storage system, so that repeated short circuits in the DC intermediate circuit are first protected or compensated by the fuses of the fuse module and only then protected or compensated by the internal fuses of the energy storage system.

[0038] In an advantageous further development, each fuse of the fuse module is connected serially to an associated switch, whereby the switch is used to select the fuse of the fuse module for the (to be carried out) direct current flow.

[0039] In an advantageous further development, an additional switch is provided in the fuse module, which is electrically connected in parallel to the selectable fuses of the fuse module.

[0040] The auxiliary switch is open as long as a selectable fuse of the fuse module is available or in use for the resulting direct current flow.

[0041] The auxiliary switch is only closed when no selectable fuse of the fuse module is available for the DC current flow. In an advantageous embodiment, the fuse module is arranged at a central and easily accessible location in the drive system of the rail vehicle.

[0042] In an advantageous further development, the backup module is located outside the energy storage system.

[0043] In an advantageous further development, the fuses of the fuse module are arranged in a circle relative to each other when viewed in a plane. The first poles of the fuses are connected in parallel by means of busbars. These poles form a first connection of the fuse module.

[0044] The second poles of each fuse can be individually selected via a rotatable or movable contact.

[0045] A second pole of a selected fuse forms a second connection of the fuse module via the rotatable or movable contact.

[0046] In an advantageous further development, a DC / DC converter is provided between the energy storage system and the DC intermediate circuit to adjust the voltages.

[0047] The DC / DC converter preferably also includes an inductor that is located between the DC intermediate circuit and the energy storage system.

[0048] Advantages:

[0049] The present invention introduces a freely selectable number of redundancy levels between the output of the energy storage system and the input of the DC link via the fuse module, which enables compensation of multiple short circuits in the DC link.

[0050] The fuse module eliminates the need to replace fuses inside the energy storage system after a predetermined number of short circuits. This increases the availability of the rail vehicle and reduces the costs and effort associated with replacing fuses within the energy storage system. Once the predetermined number of short circuits is reached, the fuse module is replaced cost-effectively.

[0051] The safety module can be easily retrofitted to existing rail vehicles and is compatible with the familiar fuses inside the energy storage system.

[0052] The use of the fuse module does not require any additional specifications for the saturation inductance of the DC link and does not cause any additional losses.

[0053] The use of the safety module allows for a compact design within an assembly, thus saving volume and weight.

[0054] Character description:

[0055] The invention is explained in more detail below with the aid of a drawing. The drawing shows:

[0056] FIG 1 shows an exemplary arrangement for securing an energy storage device of a rail vehicle according to the present invention,

[0057] FIG 2 with reference to FIG 1 shows a bottom view of an exemplary mechanical implementation of the safety module,

[0058] FIG 3 with reference to FIG 2 shows a front view of the fuse module,

[0059] FIG 4 with reference to FIG 2 shows a top view of the safety module, and

[0060] FIG 5 shows the known arrangement described in the introduction for securing an energy storage device of a rail vehicle.

[0061] FIG 1 shows an exemplary arrangement for securing an energy storage system ESS of a rail vehicle according to the present invention.

[0062] The energy storage system ESS is connected to a DC link GSZK, which includes an inductor L and a (smoothing) capacitor Czk. The energy storage system ESS feeds direct current into the DC link GSZK.

[0063] The DC link GSZK is connected on its output side to a converter UMR, which converts the supplied direct current into alternating current. This alternating current then powers a traction motor M to drive the rail vehicle. A fuse module CFM is connected in series between the output of the energy storage system ESS and the input of the DC link GSZK, through which the direct current from the energy storage system ESS passes to the DC link GSZK.

[0064] The CFM fuse module includes a number of z fuses CF1 to CFz connected in parallel, which in the event of a short circuit in the DC intermediate circuit GSZK operate selectively to internal fuses of the ESS energy storage system.

[0065] Each of the fuses CF1 to CFz can be selected via an associated switch S1 to Sz in order to connect the output of the energy storage system ESS to the input of the DC intermediate circuit GSZK via a selected fuse (S1 to Sz).

[0066] This selection is described in detail below:

[0067] In the first state of the CFM fuse module, a first switch S1 is closed. This means that a corresponding first fuse CF1 of the CFM fuse module is selected for the DC current flow from the ESS energy storage system to the DC intermediate circuit GSZK.

[0068] All other switches S2 to Sz and an additional switch Sb, which is connected in parallel to switches S1 to Sz or in parallel to the associated fuses CF1 to CFz, are open.

[0069] In the event of a short circuit (KS) in the DC link (GSZK), the first fuse (CF1) is triggered – it blows or is destroyed. The DC current flow is thus interrupted, and the energy storage system (ESS) and the DC link (GSZK) are electrically isolated from each other.

[0070] After the first fuse CF1 is triggered, the associated first switch S1 is opened and the second fuse CF2 is selected via its associated second switch S2.

[0071] This means that the direct current flow from the energy storage system ESS to the direct current intermediate circuit GSZK occurs via the second fuse CF2 of the fuse module CFM.

[0072] All other switches (S1, S3, ... Sz and the auxiliary switch Sb) are open. In the event of a short circuit KS in the DC link GSZK, the second fuse CF2 is triggered – it blows or is destroyed. The DC current flow is thus interrupted, and the energy storage system ESS and the DC link GSZK are electrically isolated from each other.

[0073] After the second fuse CF2 is triggered, the associated second switch S2 is opened and another fuse (not shown here) is selected via its assigned switch.

[0074] This ensures that the direct current flow from the energy storage system ESS to the direct current intermediate circuit GSZK is further protected by the fuse module CFM.

[0075] All other switches (S1, S2, ... Sz and the additional switch Sb) are open.

[0076] The described sequence is maintained for each subsequent short circuit (KS) until the last fuse (CFx) is blown. The switch-fuse combination thus protects a total of z short circuits (KS).

[0077] In the event of a subsequent short circuit KS, all tripped fuses CF1 to CFz are bypassed via the auxiliary switch Sb.

[0078] From this point on, there is no longer any redundancy via the CFM safety module; the subsequent short circuit KS is then only protected by internal (melt) fuses of the ESS energy storage system.

[0079] The number of possible short-circuit events in the DC link GSZK with the subsequent reconnection of the energy storage system ESS to the DC link GSZK is adjusted via the number z of fuses CF1 to CFz.

[0080] This optimizes the redundancy and availability of the rail vehicle to meet customer requirements.

[0081] An optional freewheeling diode Df absorbs energy stored in the inductor L at the point of disconnection, thereby reducing the arc time in fuses CF1 to CFz and improving selectivity with internal fuses of the energy storage system ESS (see F1.1 to F2.x below). Optionally, components CF1 to CFz, Sb, and S1 to Sz, along with the freewheeling diode Df, can be combined in a single assembly and installed at a central and easily accessible location within the rail vehicle's drive system.

[0082] The CFM fuse module is located outside the ESS energy storage system, allowing for easy replacement of the blown fuses S1 to Sz.

[0083] If the customer does not require operational separation of the energy storage system ESS from the DC intermediate circuit GSZK, the planned fuse module CFM can be omitted and replaced by a copper busbar.

[0084] The ESS energy storage system has a number x of battery strings B1 to Bx connected in parallel.

[0085] Each battery string B1 to Bx has one or two overcurrent protection elements Fn.x, where n=1 or n=2 represents double protection per battery string B1 to Bx.

[0086] As a representative example, with x=1 in the first battery string B1, a positive side of a battery cell of the first battery string B1 is connected to the DC intermediate circuit GSZK via a first fuse F1.1, which is designed as a fast-acting fuse.

[0087] Accordingly, a negative side of a battery cell of the first battery string B1 is connected to the DC intermediate circuit GSZK via a second fuse F2.1, which is also designed as a fast-acting fuse.

[0088] A rail SCH traversed by the rail vehicle forms the ground potential as the reference potential of the block diagram. Preferably, the respective fuses Fnx are arranged or installed as close as possible to the battery cells of the battery strings B1 to Bx.

[0089] FIG 2 shows, with reference to FIG 1, a bottom view of an exemplary mechanical realization of the CFM safety module, while FIG 3 shows a front view of the CFM safety module and FIG 4 shows a top view of the CFM safety module.

[0090] The required fuses CF1 to CFz and fuse Sb are arranged in a circular pattern in a single plane. The lower poles of fuses CF1 to CFz are connected in parallel via busbars, forming an input of the fuse module CFM, labeled "IN".

[0091] A rotatable RKON contact is installed on one upper side of the fuse bundle, which is operated, for example, by means of an actuator (not shown here).

[0092] Depending on the tripping state, one of the circularly arranged fuses CF1 to CFz is selected using the rotating contact RKON or contacted at its upper pole.

[0093] The center of rotation of the rotating contact RKON forms an output of the safety module CFM, designated as "OUT".

[0094] After all fuses CF1 to CFz have tripped, the auxiliary switch Sb, designed as a busbar, is contacted.

Claims

Patent claims 1. Arrangement for the safeguarding of an energy storage system (ESS) of a rail vehicle, - with a rail vehicle that has an energy storage system (ESS), a fuse module (CFM), a DC link (GSZK) and an inverter (UMR), - where the energy storage system (ESS) is connected to the DC link (DC link) via the backup module (CFM), - so that direct current from the energy storage system (ESS) passes through the fuse module (CFM) into the DC intermediate circuit (DCC), - in which the DC intermediate circuit (DCC) is connected to the converter (DCC) on the output side, so that direct current from the DC intermediate circuit (DCC) can be used via the converter (DCC) to drive the rail vehicle, - in which the fuse module (CFM) has a number (z) of individually selectable fuses (CF1 to CFz) connected in parallel to each other, - in which a first fuse (CF1 to CFz) of the fuse module (CFM) is selected and switched in such a way that the direct current from the energy storage system (ESS) passes through the first fuse (CF1 to CFz) into the DC intermediate circuit (DCC), - in which, in the event of a short circuit (KS) in the DC intermediate circuit (GSZK), the selected first fuse (CF1 to CFz) is switched in such a way that the DC current flow through it is permanently interrupted, - in which, after the termination of the short circuit (KS), a second fuse (CF1 to CFz) of the fuse module (CFM) is selected and switched in such a way that the direct current from the energy storage system (ESS) enters the DC intermediate circuit (GSZK) through the second fuse (CF1 to CFz).

2. Arrangement according to claim 1 , - in which each fuse (CF1 to CFz) of the fuse module (CFM) is connected serially to a corresponding switch (S1 to Sz), - the selection of the fuse (CF1 to CFM) of the fuse module (CFM) is made via the switch (S1 to Sz).

3. Arrangement according to one of the preceding claims, - where an additional switch (Sb) is provided in the fuse module (CFM), - where the auxiliary switch (Sb) is connected in parallel to the selectable fuses (CF1 to CFz) of the fuse module (CFM), - where the auxiliary switch (Sb) is open as long as a selectable fuse (CF1 to CFz) of the fuse module (CFM) is used for the DC current flow, - where the auxiliary switch (Sb) is only closed when no selectable fuse (CF1 to CFz) of the fuse module (CFM) is available for DC current flow.

4. Arrangement according to one of the preceding claims, - in which the energy storage system (ESS) has internal fuses (F1.1 to F2.x), which are preferably designed as fuse links, and - in which the energy storage system (ESS) has a number of battery strings (B1 to Bx) connected in parallel, which are protected by one or two of the internal fuses (F1.1 to F2.x).

5. Arrangement according to claim 4, - where the fuses (CF1 to CFz) of the fuse module (CFM) are selectively connected to the internal fuses (F1.1 to F2.x) of the energy storage system (ESS), - so that repeated short circuits (KS) in the DC intermediate circuit (GSZK) are first protected by the fuses (CF1 to CFz) of the fuse module (CFM), and - only then are they protected by the internal safeguards (F1.1 to F2.x) of the Energy Storage System (ESS).

6. Arrangement according to one of the preceding claims, wherein the safety module (CFM) is arranged at a central and easily accessible location in the drive system of the rail vehicle.

7. Arrangement according to one of the preceding claims, wherein the backup module (CFM) is arranged outside the energy storage system (ESS).

8. Arrangement according to one of the preceding claims, - in which the fuses (CF1 to CFz) of the fuse module (CFM) are arranged in a circular pattern in one plane, - where the first poles of the fuses (CF1 to CFz) are connected in parallel by means of busbars, these poles forming a first connection of the fuse module (CFM), - where the second poles of the fuses (CF1 to CFz) can be individually selected via a rotatable or movable contact, - in which a second pole of a selected fuse (CF1 to CFz) forms a second connection of the fuse module (CFM) via the rotatable or movable contact.

9. Arrangement according to one of the preceding claims, wherein a DC / DC converter for voltage adjustment is arranged between the energy storage system (ESS) and the direct current intermediate circuit (DCC).

10. Arrangement according to claim 9, wherein the DC / DC converter includes an inductance located between the DC intermediate circuit (DCC) and the energy storage system (ESS).

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