Accumulator housing for a rail vehicle

Abstract

The invention relates to an accumulator housing (1) for a rail vehicle, comprising a container (2) closed on all sides and fastening means (3) for releasably fastening the accumulator housing (1) to a rail vehicle, wherein at least one discharge nozzle (4) is arranged in a wall bordering the accumulator housing (1), through which discharge nozzle combustion gas can escape in the form of a turbulent free jet.

Description

[0001] Description

[0002] Battery housing for a rail vehicle.

[0003] Technical area

[0004] The invention relates to an accumulator housing for a rail vehicle.

[0005] State of the art

[0006] Rail vehicles, particularly those for passenger transport, are equipped with electric accumulators which can keep technical equipment running for a certain period of time, even in the event of a power failure. The amount of energy stored in these accumulators has risen steadily over the last few decades due to increased safety and comfort requirements, so that capacities of several 10 0Ah and more are now used at the 110V commonly used in rail vehicles. The accumulator technology used must ensure that the accumulators are both light and small, and therefore have a high energy density in relation to both the mass and the volume of the accumulators. The lead-acid batteries used in the past cannot meet these requirements, so that today mostly so-called lithium-ion batteries are used.These batteries have the required energy density, but are sometimes more sensitive than other battery technologies. In particular, the permissible charging and discharging currents must be strictly adhered to. This usually requires individual cell monitoring. This monitors the relevant parameters and the temperature of the battery cell and switches the cell off if certain values ​​are exceeded. Despite these measures, fully charged lithium-ion batteries in particular can destroy themselves if they overheat or are mechanically damaged. The energy stored in the battery cell is released in a very short time through a direct chemical reaction in the form of heat. This reaction releases a large amount of smoke and toxic gases, and the resulting heat is capable of melting light metal containers.These batteries are therefore almost always located outside the passenger compartments in rail vehicles. An installation location below a car body is particularly advantageous because this allows molten material to drip down towards the track bed. Smoke development is particularly problematic, however, in vehicles traveling in tunnels, particularly subways. It is not practical to use sealed battery housings made of metals with a correspondingly high melting point (steel), as these would have to be designed for such high internal pressure that their mass would not justify the use of lithium-ion batteries. According to the state of the art, battery housings made of light metal, typically an aluminum alloy, are used. These have a venting device through which increased internal pressure can escape to the outside.In the process, all toxic combustion gases escape and, under unfavorable conditions such as in tunnels or depressions, can form areas with high combustion gas concentrations. Description of the invention.

[0007] The invention is therefore based on the object of specifying an accumulator housing for a rail vehicle which, in the event of a fire in the accumulators located therein, releases the resulting fire gases into the atmosphere in such a way that they are strongly diluted or neutralized by the ambient air and local accumulations of highly concentrated fire gases are prevented.

[0008] This object is achieved by a battery housing having the features of claim 1. Advantageous embodiments are the subject of subordinate claims.

[0009] According to the basic idea of ​​the invention, an accumulator housing for a rail vehicle is constructed, comprising a container closed on all sides and fastening means for detachably fastening the accumulator housing to a rail vehicle, wherein at least one outlet nozzle is arranged in a wall delimiting the accumulator housing, through which combustion gas can escape in the form of a turbulent free jet.

[0010] This offers the advantage of being able to use the inherently high mixing rates of a turbulent free jet, so that fire gases escaping from the accumulator housing can be mixed with the ambient air in such a way that high local concentrations of fire gases in the area surrounding the rail vehicle are avoided. In general, a free jet is to be regarded as completely turbulent if the Reynolds number characterising the free jet is above 2000. According to the invention, an accumulator housing is constructed from a container which is closed on all sides and in which the accumulator cells can be arranged. At least one outlet nozzle is to be arranged in a wall bounding the accumulator housing, through which outlet nozzle fire gases produced in the event of a fire in the accumulators can escape into the environment.This outlet nozzle must be dimensioned so that in the event of a battery fire, the combustion gas escapes in the form of a turbulent free jet due to the internal pressure created in the container.

[0011] A free jet is the flow of a fluid from a nozzle into the free environment, which is not influenced by any further restrictions. Such a free jet ensures good mixing of the escaping fluid with the free environment (generally air), due to the turbulent movement of the fluid and the resulting entrainment of air from the environment. Typically, after a distance of approximately 10 times the internal diameter of the outlet nozzle, the mixing has progressed to such an extent that the concentration of fire gases in the ambient air has fallen below an extremely dangerous level. In contrast, conventional accumulator housings use flaps which are opened by the fire gases, allowing the internal pressure to escape and preventing the risk of the accumulator housing suddenly bursting.However, high local concentrations of fire gases can occur in the immediate vicinity of the rail vehicle. These fire gas concentrations make it difficult to evacuate passengers, particularly in tunnels, and there is a risk that excessively high concentrations of fire gases will be sucked in through the vehicle ventilation system and fed into the passenger compartment. At least one outlet nozzle must be provided for each accumulator housing, which must be oriented in a direction that allows the most undisturbed outflow possible. If the accumulator housing is arranged underfloor, this can be in the direction of the track bed, for example, since there are usually other so-called underfloor containers provided in the longitudinal direction of the vehicle, which would prevent the formation of a turbulent free jet.If the accumulator housing is located on the roof of a rail vehicle, it is particularly recommended that the exhaust air should be directed vertically upwards, as this ensures particularly good removal of the fire gases.

[0012] Since a container of an accumulator housing usually has small walls, the outlet nozzles can preferably be designed as nozzle elements in the form of welded-in plug-in or screw elements. The nozzle element consists of an elongated, cylindrical block into which the nozzle geometry is incorporated. A plate can be provided on the inner wall of the container to hold the nozzle element securely in position when the internal pressure of the container increases. The nozzle element projects either outwards beyond the container wall or inwards beyond.

[0013] The outlet nozzles are preferably closed on the outside when installed to prevent dirt and moisture from entering the battery container. For this purpose, a closure, for example a plug or diaphragm, made of a material can be provided which is expelled, breached or destroyed by the fire gases in the event of a battery fire. In a particular embodiment of the invention, if a plurality of outlet nozzles are provided, these are each equipped with closures of different strengths. As the internal pressure increases, these closures are thus gradually breached and the nozzles are released gradually, i.e. in stages depending on the prevailing internal pressure. The gradual increase in the effective flow cross-section guarantees the outflow velocities of the fire gases necessary for mixing with the outside air, even at lower internal pressures.

[0014] A preferred embodiment of the invention provides for increasing the mixing rates of the free jet by designing the outlet nozzle to generate a self-excited oscillating free jet. An oscillating free jet is a free jet whose direction undergoes a transient, fluctuating / oscillating / rotating movement. This can be caused, for example, by an unstable, unsteady flow pattern in the area of ​​the nozzle causing the outlet direction to fluctuate / oscillate / rotate around the nozzle axis. This is possible with special nozzles, for example so-called precessing jet nozzles, Karman vortex nozzles, flip-flop nozzles, in which the oscillation of the outlet direction of the free jet occurs self-excitedly when the flow starts and does not have to be actively caused by actuators.Alternative systems use fluid-structure coupling with an unstable fluttering object in the area of ​​the nozzle to cause a self-excited, oscillating free jet (flapping jet). If the internal pressure in an accumulator is so high during a fire that it cannot be dissipated quickly enough via the outlet nozzles, thus creating the risk of the accumulator housing bursting, an emergency device can be provided which allows the fire gases to flow out of the container parallel to the outlet nozzles. This emergency device can comprise a flap in a wall of the container which is pre-tensioned in the closed position, for example by a spring, and which opens when a certain internal pressure is exceeded and closes again automatically when the internal pressure falls below this certain value.A particular advantage is that after the reduction of this critical pressure, the continued discharge of fire gases occurs exclusively through the discharge nozzles.

[0015] This emergency device can prevent an uncontrolled spread of a battery fire, particularly in the direction of a passenger compartment.

[0016] A battery housing according to the invention comprises fastening means for detachably fastening the battery housing to a rail vehicle. The specific design of these fastening means depends on the intended installation location on a rail vehicle, whereby in most applications underfloor installation is used and corresponding fastening means, for example formations to form a screw connection, must be provided. In a further development of the invention, an additional volume can be provided on the battery housing which is designed to accommodate fire gas. This additional volume is coupled to the closed container and designed for the inflow of fire gas. This provides the fire gas with a larger space than the space remaining in the container.In this way, the internal pressure in the container that develops during a fire can be reduced, preventing the container from bursting. Since the provision of an outlet nozzle, while the container is otherwise sealed, increases the internal pressure during a battery fire compared to conventional venting devices, there is a fundamental risk of the container bursting, resulting in the undirected release of combustion gases and, consequently, the formation of a locally high concentration of combustion gases.

[0017] This additional volume can be designed as a cavity in the accumulator housing, but this is usually not feasible due to the typically cramped installation conditions in a rail vehicle.

[0018] It is therefore recommended that the additional volume be designed to be foldable, with it having a rest position in which it is folded and stowed. In the event of a storage battery fire, the resulting fire gases initially fill the space available in the container until the internal pressure in the container has risen to such an extent that the additional volume is brought into its usable position by this internal pressure. In this way, the additional volume can be unfolded and brought into its usable position by the inflow of smoke gas. The internal pressure then drops again as a result of the flow out through the provided outlet nozzles, and the risk of the container bursting is reduced. The additional volume can advantageously be made at least partially from flexible material, for example a heat-resistant fabric.

[0019] A preferred embodiment of the invention provides for a reduction in the toxicity of the fire gases escaping from the accumulator housing by means of an afterburning device. Such an afterburning device comprises an inlet device for a combustible gas which opens into the outlet nozzle and an ignition device for the combustible gas. The combustible gas is ignited and the toxic substances in the fire gas are chemically converted so that they are essentially neutralized. All commonly used gases, such as propane or butane, can be used as the combustible gas. A particularly high temperature is not required. However, an ignition device must be provided because the temperature of the fire gases from a battery fire at the outlet point (outlet nozzle) is not necessarily sufficient to reliably ignite the combustible gas mixture produced.Spark gaps, similar to the ignition system of an internal combustion engine, can be used as the ignition device. This ignition device should preferably be operated continuously after activation so that the afterburning cannot be extinguished.

[0020] If such an afterburner device is provided, the discharge direction of the discharge nozzle is of great importance, since it must be assumed that the evacuation of passengers will take place simultaneously with the operation of the afterburner device. The discharge nozzle should therefore preferably be directed in a direction that poses no danger to the surrounding area, particularly toward the track bed.

[0021] It is advantageous to equip the afterburner device with a safety device against flashback, which prevents the flame from entering the container of the accumulator housing. This can be achieved by cooling the flame temperature below the ignition temperature of the mixture before the flame enters the container. For this purpose, for example, a grid or honeycomb structure can be provided on the side of the outlet nozzle facing the interior of the container (inlet side of the nozzle), which cools the penetrating flame at this point by dissipating heat into the container material.

[0022] According to a preferred embodiment, the triggering of the afterburning device is brought about by a control device which controls the inflow of the combustible gas and the ignition device as a function of a parameter detected by a sensor inside the container. The temperature inside the container can be used as a parameter, but this parameter reacts slowly, so it is more advantageous to use the internal pressure in the container as a criterion for triggering the ignition device. Furthermore, other measured values ​​can be recorded and used to trigger the afterburning. These measured values ​​can be the temperature in the accumulator cells, or there can be detection of smoke or certain chemical substances formed in the container during a fire.

[0023] A further preferred embodiment of the invention provides a neutralization device in which the fire gas is mixed with neutralizing substances (compensation substance) and the fire gas thus neutralized is released into the environment via at least one outlet nozzle. In this case, a mixing chamber into which at least one compensation substance can be introduced is arranged in the flow path of the fire gas upstream of the outlet nozzle. This mixing chamber is designed to swirl the fire gas with the compensation substance so that neutralization is essentially complete as soon as the fire gas enters the outlet nozzle. The type of compensation substance is determined by the composition of the accumulators, which also determines the chemical composition of the fire gas.The compensation substances can be supplied in liquid, gaseous, or powder form. A gaseous compensation substance stored as a compressed gas is particularly advantageous, as its compressed gas properties allow it to flow automatically into the mixing chamber. Liquids and powdered solids require an additional propellant gas and an atomizer. If the composition of the fire gas requires the supply of several different compensation substances, this is just as easily possible.

[0024] Furthermore, it is possible to omit the mixing chamber if it is ensured that the chemical reaction of the compensating substances occurs sufficiently quickly. In this case, feeding the compensating substances directly into the outlet nozzle is sufficient.

[0025] A further simplification of the neutralization system can be achieved by injecting compensating substances laterally into the free jet outside the housing. Appropriate feeds for the compensating substances must be provided outside the discharge nozzle, whereby the turbulent discharge of the combustion gases causes mixing with the compensating substances in the free jet outside the discharge nozzle.

[0026] The neutralization device is preferably triggered in a similar way to the described afterburning device by means of a control device which controls the inflow of the at least one compensation substance as a function of a parameter detected by a sensor inside the container.

[0027] The above-mentioned developments of the invention, i.e. the additional volume and the afterburning device or the neutralization device, can be provided in any combination.

[0028] Brief description of the drawings

[0029] Examples include:

[0030] Fig. l Battery housing.

[0031] Fig. 2 Accumulator housing with additional volume.

[0032] Fig. 3 Accumulator housing with additional volume in

[0033] Position of use .

[0034] Fig. 4 Accumulator housing with afterburner device.

[0035] Fig. 5 Accumulator housing with neutralization device.

[0036] Fig. 6 Outlet nozzles with closure. Execution of the invention

[0037] Fig. 1 shows an example and schematically a battery housing. It shows a section through a battery housing 1 which comprises a closed container 2 for holding battery cells 5 and which is equipped with fastening means 3 which allow the battery housing 1 to be detachably arranged on a rail vehicle. In the walls of the battery housing 1, i.e. in the closed container 2, three outlet nozzles 4 are arranged, for example, which discharge the fire gas produced when the battery cells 5 catch fire into the air surrounding the battery housing 1. A fire in the battery cells 5 causes the internal pressure in the closed container 2 to increase, so that the fire gas escapes with corresponding pressure and consequently in the form of a turbulent free jet. In the container shown in Fig.In the embodiment shown, three outlet nozzles 4 are used, each outlet nozzle 4 being directed in a different direction. In this case, one outlet nozzle 4 is arranged laterally in the installed position of the accumulator housing 1, normal to the longitudinal axis, and one outlet nozzle 4 is arranged in the direction of the track bed. The number, arrangement and dimensioning of the nozzle cross-section are to be determined as a function of the expected internal pressure in the closed container 2, so that a maximum internal pressure reached does not impair the structural integrity of the closed container 2, but ensures that the fire gas flows out in the form of a turbulent free jet.

[0038] Fig. 2 shows an example and schematically a

[0039] Accumulator housing with additional volume. An accumulator housing 1 is shown, similar to the embodiment shown in Fig. 1, but which only comprises two outlet nozzles 4. An additional volume 6 is provided which is oriented in the direction of the track bed in the installed position of the accumulator housing 1. The additional volume 6 is designed as a flexible extension of the interior of the closed container 2, wherein the interior can be expanded by the action of the pressure of the fire gas by means of folds 7 in a flexible material. The rest position of the additional volume 6 is shown, without the action of an increased internal pressure.

[0040] Fig. 3 shows an example and schematically an accumulator housing with an additional volume in the position of use. The accumulator housing 1 from Fig. 2 is shown during or after a fire, wherein as a result of the increased internal pressure in the closed container 2, a wall of the closed container 2 was moved in the direction of the track bed using the folds 7. The volume in the accumulator housing 1 expanded in this way lowers the internal pressure and reduces the risk of bursting. The function of the outlet nozzles 4 is the same as in embodiments without additional volume 6.

[0041] Fig. 4 shows, by way of example and schematically, an accumulator housing with an afterburning device. According to this exemplary embodiment, the fire gas is thermally treated by supplying the fire gas to a flame which is generated by a combustible gas 8. For example, the combustible gas 8 is stored as a compressed gas and can flow via an electromagnetic valve 9 into an outlet inside the outlet nozzle 4. To ensure the ignition of the combustible gas 8, an ignition device 12 is arranged at the outlet of the outlet nozzle 4, which ignition device is designed, for example, as a spark ignition. To trigger the afterburning device, a control unit 10 is provided, to which a sensor 11 inside the closed container 2 is coupled.This sensor 11 detects a specific parameter, preferably the internal pressure of the closed container 2, and transmits a signal corresponding to this parameter to the control unit 10, which in turn controls the inflow of the combustible gas by opening the valve 9 and triggering the ignition device 12.

[0042] Fig. 5 shows an example and schematically a battery housing with a neutralization device. According to this exemplary embodiment, a neutralization device is additionally provided which reduces or even eliminates the toxicity of the fire gas by admixing certain chemical substances. As an example, three compensation substances 16, 17, 18 are provided which are stored separately as compressed gases and whose outflow is controlled by electromagnetic valves. The compensation substances 16, 17, 18 are for this purpose fed to a mixing chamber 13 which is arranged upstream of an outflow nozzle 4, in which they are mixed as intensively as possible with the flowing fire gas and only then is the latter released into the environment through the outflow nozzle 4 with a reduced content of toxic substances. The activation of this neutralization device takes place in a similar way to the activation of the afterburning device according to the method shown in Fig.4. A signal corresponding to a specific parameter is fed to a control unit 14 from a sensor 15, and this control unit 14 causes the valves of the compressed gas cylinders of the compensation materials 16, 17, 18 to open.

[0043] It is particularly advantageous to equip the control unit 14 of the neutralization device and also the control unit 10 of the afterburning device with an interface 19 for data communication with a vehicle control system, so that when the neutralization device or the afterburning device is triggered, a message can be sent indicating that the device has been triggered. The vehicle control system can then initiate measures such as warning the driver or closing the fresh air supply to the vehicle interior.

[0044] Fig. 6 shows, by way of example and in a schematic manner, outlet nozzles, each with a closure. Three outlet nozzles 4 are shown which are arranged parallel to one another in a wall of a container 2. These outlet nozzles 4 are manufactured in one piece as separate components and are fastened to the wall of the container 2. This means that the length and nozzle cross-section required for optimum nozzle action can also be implemented in containers whose material and manufacturing process are unsuitable for the direct formation of a nozzle, for example are made from thin sheet metal. The outlet nozzles 4 are each closed with a closure 20, 21, 22, which prevents moisture, dirt, insects, etc. from penetrating the container 2.These closures 20, 21, 22 are designed in such a way that they are released and ejected by an accumulator fire that occurs, for example by the heat generated in the event of a fire or the internal pressure developing in the container 2. In order to prevent the internal pressure in the container from falling too low, so that the flow velocity of the escaping fire gases is no longer sufficient to achieve a turbulent free jet, a gradual opening of the closures 20, 21, 22 is provided. In the exemplary embodiment shown, the closures 20, 21, 22 are each designed with different strengths, as a result of which the closure 20 is opened before the closure 21 and this in turn is opened before the closure 22. If, for example, the internal pressure only reaches a value at which the closure 20 opens, the closures 21 and 22 remain closed.However, if the internal pressure increases, the closure 21 opens first and, if the internal pressure continues to rise, the closure 22 opens. If even completely opening all closures of all outlet nozzles in a container is not enough to limit the internal pressure to the permissible maximum internal pressure, an emergency device can be provided which also allows the fire gases to flow out of the container 2 parallel to the outlet nozzles 4. This can, for example, be designed as a flap pre-tensioned by a spring force. In this way, this emergency device closes again when the internal pressure drops to a permissible value and the fire gases are further discharged as a turbulent free jet via the outlet nozzles 4.

[0045] List of names

[0046] 1 battery housing

[0047] 2 containers

[0048] 3 fasteners

[0049] 4 Outlet nozzle

[0050] 5 accumulator cell

[0051] 6 additional volume

[0052] 7 Folding

[0053] 8 Flammable gas

[0054] 9 Valve

[0055] 10 Control unit for afterburner system

[0056] 11 Sensor afterburner device

[0057] 12 Ignition device

[0058] 13 Mixing chamber

[0059] 14 Control unit neutralization device

[0060] 15 Sensor neutralization device

[0061] 16 First compensation material

[0062] 17 Second compensation material

[0063] 18 Third compensation substance

[0064] 19 Interface to vehicle control

[0065] 20 First closure

[0066] 21 Second closure

[0067] 22 Third lock

Claims

Accumulator housing (1) for a rail vehicle, comprising a container (2) closed on all sides and fastening means (3) for detachably fastening the accumulator housing (1) to a rail vehicle, wherein at least one outlet nozzle (4) is arranged in a wall delimiting the accumulator housing (1), through which outlet nozzle fire gas can escape in the form of a turbulent free jet, characterized in that different closures (20, 21, 22) are arranged on a plurality of outlet nozzles (4), which release the outlet nozzle (4) assigned to them in a staggered manner depending on the prevailing internal pressure. Accumulator housing (1) for a rail vehicle according to claim 1, characterized in that an additional volume (6) is provided, coupled to the closed container (2), into which additional volume fire gas can flow.Battery housing (1) for a rail vehicle according to claim 2, characterized in that the additional volume (6) is formed from flexible material which is folded when stowed in its rest position and which is brought into its unfolded position of use by the inflow of combustion gas. Battery housing (1) for a rail vehicle according to one of claims 1 to 3. characterized in that an afterburning device, comprising an inflow device for a combustible gas opening into the outflow nozzle and an ignition device for the combustible gas, is provided on at least one outflow nozzle (4). Accumulator housing (1) for a rail vehicle according to claim 4, characterized in that a control device is provided which controls the inflow of the combustible gas and the ignition device as a function of a parameter detected by a sensor inside the container. Accumulator housing (1) for a rail vehicle according to one of claims 1 to 3, characterized in that a neutralization device is provided on the at least one outflow nozzle (4), comprising a mixing chamber arranged in the flow path of the combustion gas to the outflow nozzle (4), into which mixing chamber at least one compensation substance can be introduced.Accumulator housing (1) for a rail vehicle according to claim 6, characterized in that the at least one compensation substance is gaseous, liquid, or powdery. Accumulator housing (1) for a rail vehicle according to claim 6 or 7, characterized in that. a control device is provided which controls the inflow of the at least one compensation substance depending on a parameter detected by a sensor inside the container. Accumulator housing for a rail vehicle according to one of claims 1 to 9, characterized in that the at least one outlet nozzle (4) is closed with a closure (20) which is expelled, breached or destroyed by the fire gases in the event of an accumulator fire. Accumulator housing (1) for a rail vehicle according to one of claims 1 to 9, characterized in that an emergency device is provided which, if a maximum permissible internal pressure of the container (2) is exceeded, additionally allows the fire gases to escape parallel to the outlet nozzles (4) and which closes again automatically if the internal pressure drops below the specified value.Accumulator housing (1) for a rail vehicle according to one of claims 1 to 10, characterized in that the outlet nozzle (4) is designed to generate a self-excited oscillating free jet. Accumulator housing (1) for a rail vehicle according to claim 4, characterized in that. which the afterburner with a Equipped with a safety device against flashback, which prevents the flame from entering the container of the accumulator housing. Accumulator housing (1) for a rail vehicle according to claim 12, characterized in that the safety device comprises a grid or honeycomb structure on the side of the outlet nozzle (4) facing the interior of the container (2).

Images