DE102013209835A1 - Module separation in battery systems in the event of accidents - Google Patents

Abstract

Battery system (2) for a vehicle, comprising at least two battery modules (4), the battery modules (4) being connected in series, characterized in that the battery system (2) also has a separating element (6), the separating element (6) is arranged in series between the battery modules (4), the separating element (6) being set up to provide a substantially loss-free conductive connection during regular operation of the vehicle and the separating element (6) being set up in such a way that in the event of an accident the Conductive connection between the battery modules (4), in particular non-reversible, can be interrupted.

Description

The present invention relates to electric or hybrid vehicle technology. In particular, the present invention relates to battery system technology for electric and hybrid vehicles. Further particularly, the present invention relates to a battery system for a vehicle and a vehicle, in particular electric or hybrid vehicle.

State of the art

Battery systems for electric or hybrid vehicles, thus their traction batteries, are regularly constructed with a high system voltage in order to realize the required drive power with the lowest possible currents and thus small cable cross-sections or ohmic losses. These battery systems are often housed in or directly under the passenger compartment or in the engine compartment. In the event of accidents, occupants of the vehicle, for example the driver, as well as rescue personnel may be exposed to the risk of high DC voltages. Furthermore, a high voltage may lead to arcing, which is usually not self-extinguishing. The development of heat can result in subsequent burn marks or the evaporation of large quantities of metallic material. Particularly relevant is the comparatively large stored amount of energy in a battery system for electric or hybrid vehicles.

In an accident scenario, there may thus be uncertainty in extinguishing or salvaging forces, which may be restrained in their use, in particular with regard to the use of extinguishing water and / or heavy salvage equipment, and in particular the principle of intrinsic safety before recovery follow.

Disclosure of the invention

One aspect of the present invention may be seen to provide an improved battery system for vehicles, particularly electric or hybrid vehicles.

Accordingly, a battery system for a vehicle and a vehicle, in particular electric or hybrid vehicle according to the independent claims is displayed. Preferred embodiments will be apparent from the dependent claims.

A battery system for the drive (traction battery) of electric or hybrid vehicles can be used as a large single module, e.g. be housed in the sandwich floor or rear of the vehicle, or consisting of several individual modules distributed in the vehicle. It is regularly well protected for normal operation. Battery management systems are used which, on the one hand, monitor single cells for overcharging during charging or recuperation, e.g. by overvoltage monitoring, on the other hand allow temperature monitoring of the modules, so as to prevent a thermal overload of the cells in normal operation. Furthermore, the single cell monitoring may provide monitoring of undervoltage, thus preventing deep discharge which may possibly lead to internal short circuits and thus overheating of the battery cells. An insulation test against the vehicle body may continue to detect an insulation fault of lines, in which case the vehicle can be electronically protected against recommissioning.

Furthermore, fuses are regularly provided within a battery system, which ensure a short circuit on the battery cables or in the electric inverter. In addition, battery protectors, electromagnetic switches for high current applications are provided in known battery systems, which are opened in the idle state of the vehicle or in the fault state or in an accident while switching the battery lines in the vehicle de-energized.

However, the aforementioned safety devices usually do not interfere with the destruction of the battery housing, for example in the case of an accident or when vehicles are sinking into waters. Thus, by the destruction of the insulating housing or by the penetration of metallic body parts or the unfolding of battery modules shorts between the cells and connecting lines arise or connecting lines are exposed at high voltages from the insulation. On the other hand, may be brought about by the penetration of water into battery modules, a conductive connection of the cells. These scenarios can lead to a short circuit with high voltages or arcing.

In terms of design, battery systems for electric or hybrid vehicles, thus their traction batteries, are designed as a plurality of battery modules, which are connected in series. The individual battery modules are self-contained or (hermetically) sealed housing, which in an undamaged state provide protection against contact with live parts and also against the ingress of water or extinguishing water. Such a battery module is usually constructed internally as a plurality of individual battery cells, for example six cells in series, and when fully charged has a module voltage of e.g. 24V up.

A plurality of such battery modules are subsequently also connected in series to form a battery system. For example, twelve such battery modules can be connected in series and thus achieve a total voltage of about 300 V. The wiring of the individual battery modules with each other is done regularly by external conductor elements connected to terminal terminals of the individual battery modules, for example, properly screwed. These conductor elements can also be protected with respect to contact and liquid.

For example, because the voltage of a single battery module of, for example, 24V is substantially equal to the voltage used in conventional truck starting batteries, for example, recovery forces are familiar and skilled in dealing with such voltages.

Only the series connection of a plurality of battery modules, which only results in a comparatively high voltage of, for example, 300 V, represents an increased and unfamiliar hazard potential.

According to the invention, it is now proposed to suitably break up the series connection of the battery modules, so that there are only more individual battery module voltages in the vehicle.

According to the invention, separating elements are provided in particular between the individual battery modules and of these for connection to the vehicle, which disconnect the serial interconnection of the battery modules in such a way that only the individual voltages of the battery modules in the vehicle are present. Thus, separating elements are provided between the battery modules, which trigger in case of accidents, reliably prevent the flow of electricity and thus interrupt the series connection of the battery modules. By introducing separating elements, which in particular trigger only in the event of serious accidents, the voltage of the battery system is thus reduced to the level of the individual battery modules, which only results in a low voltage which is harmless for contact or arcing.

The effected triggering of the separating elements is preferably made visible by a display device to the outside, so that deletion or recovery forces can visually assure that the separating elements have actually triggered and thus prevail in the interior of the vehicle only more harmless voltage conditions. Such a visualization increases the objective safety of the occupants of a vehicle or the subjective safety of the extinguishing and recovery forces. Thus it can be read from outside the vehicle, whether the safety device has triggered and the vehicle is thus substantially free of stress.

Due to the accident scenarios in which such a separating element triggers regularly, can be provided in particular that the separating elements only have to trigger once or can, thus trigger irreversible. As a result, such a separating element can have a construction which is particularly suitable for the single triggering and can therefore be constructed in a particularly simple manner. As a result, it is possible in particular to realize a comparatively low internal resistance of the separating element and thus low conduction losses for a comparatively large switching path. Such a construction may also be suitable for extinguishing an arc or for the preferred waterproof design of a separating element. The separating elements can be triggered in the vehicle via their own control devices or a separate control unit. Alternatively, e.g. To reduce costs, the triggering device for airbags or the coupled accident detection can be used to make, for example, via or parallel to the airbag control unit, the release of the separating elements. The same control unit can also be used subsequently to provide a display element at a suitable point in the vehicle, for example in the windshield area next to the A-pillar or in the side window area of the driver, which is a safe state for extinguishing and salvaging forces or generally to the outside , thus signaled a battery system with separate battery modules.

According to the invention, the separating elements are either arranged in the conductor elements or the connecting lines or their cable clamping devices between different battery modules or are alternatively installed as an integral part of a battery module in this or in their fittings.

The disconnectors can be triggered by their own control unit, via the battery control unit (BCU) or the airbag control unit. Preferably, this controller is powered by a conventional 12V / 24V energy storage, thus the car battery, with energy even during the accident. As a result, the triggering of the separating element may preferably be ensured. Alternatively or additionally, an energy storage in the control unit, for example, be provided by suitable capacitor elements, to provide release energy for the separating elements.

The separating elements can be used as electromechanical or pyrotechnic Separating devices may be formed. Particularly in the case of non-reversible separating elements, the conductive connection can be mechanically changed or destroyed. This may also be ruled out in particular that the separating elements inadvertently return to a closed state. In order not to overload an energy store, in particular in electromechanical separating elements, these can be triggered one after the other. In the case of pyrotechnic elements, however, the required tripping energy is usually comparatively low, so that they are preferably triggered substantially simultaneously.

separators 6 For example, they may be formed as known pyrotechnic switches, in which a conductive connection is separated by an explosive charge, for example, is pierced by a wedge element. Alternatively, an electromechanical separating element may be provided in which the function of the explosive charge is realized by the attractive or repulsive effect of an electromagnet on another element.

Preferably, the separating elements are activated only after opening the battery contactors. In such a case, since a global current flow is already prevented by the opening of the battery contactors, the separating elements can be dimensioned for an essentially current-free switching or line interruption and thus designed to be correspondingly small.

Release speed requirements generally may not be as high as, for example, deployment of airbag systems. In particular, the separating elements of the battery system according to the invention may be activated only after the deployment of the airbags in a vehicle to thereby also avoid an energetic overload of the vehicle systems. Such a downstream triggering may also allow the use of electromechanical switches as separating elements.

The accident detection may be done via its own sensors, in the battery control unit or using an accident detection of a central engine control unit or airbag control unit. The penetration of water into the area of the battery system is to be detected by suitably mounted sensors and evaluated as in an accident. In this case, the information regarding an accident or accident and the resulting action to be taken via a vehicle data bus, for example a CAN bus, may be transmitted to the ultimately triggering control device.

The display of the release of the separating elements and thus the safety of the battery system may preferably be carried out using a non-reversible display element, so that the display of the safe state is not accidentally deleted or disabled due to accident or again. The display of the triggering is thus preferably permanent and in particular operated mechanically and can in particular also use the same triggering mechanism, for example a pyrotechnic display element. The display is attached to a suitable location in the vehicle visible to the outside.

The separating elements can be designed such that a triggering that has taken place can be detected by an optical display on the element itself and / or by evaluation of the changed control properties on the triggering lines or by a separate sensor line (for example, separation of a sensor loop). This may facilitate maintenance or replacement of the partitions after a damage event.

The vehicle electronics preferably have a suitable monitoring device, for example in a control unit, for monitoring the correct functioning of the separating elements over the entire vehicle service life.

Embodiments of the invention are illustrated in the following drawings and explained in more detail in the following description.

Show it

1 an exemplary embodiment of a drive system for electric or hybrid vehicles with a battery system according to the present invention; and

2a C shows exemplary embodiments of the arrangement of separating elements according to the present invention

Further referring to 1 An exemplary embodiment of a drive system for electric or hybrid vehicles with a battery system according to the present invention is shown.

1 shows the schematic structure of a drive system for a vehicle, in particular an electric or hybrid vehicle. Provided for the drive of the vehicle is an electric machine 12 using elements 11a -C, for example 12V battery 11a , Inverter (Power Converter) 11b and connection elements or battery contactor (contactor) 11c , Further provided are exemplary for the engine and vehicle control responsible control devices 8a , b, for example battery control unit (BCU) 8a Electronic Control Unit (ECU) 8b connected to Internal Combustion Engine (ICE) or Range Extender engine 12 connected.

As energy storage of the vehicle is a battery system 2 provided, consisting of a plurality of battery modules 4 is constructed. This battery system 2 is, by way of example, using a fuse 18 to battery contactor 11c connected, which using the inverter 11b the electric machine 10 supplied with energy for the vehicle drive. According to the invention are between the individual battery modules 4 of the battery system 2 separators 6 arranged, which suitable for example on the battery control unit 8a are connected and controlled by this, so that in an accident case, a separation of the serial connection of the battery modules 4 is possible or can be triggered controlled by this. The battery control unit 8a can in turn information about an accident scenario of another control device of the vehicle, such as an airbag control unit, via a data bus 14 (for example, CAN bus) received.

The connection of the battery system 2 to the vehicle itself can turn through, in 1 For example, arranged outside the battery system, separating elements 6 be separated from the vehicle. Likewise, these dividing elements can also be connected to the outgoing connections of the battery system 2 be arranged in the housing.

display element 16 is in 1 shown only schematically. Preferably arranged display element 16 in the vehicle at a location suitably visible from the outside to the outside, in particular not reversible, a release of the separating elements 6 and thus a separation of the serial connection of the battery modules 4 in the battery system 2 display. At this displayed information of the display element 16 For example, rescue or rescue forces can read to what extent a possibly life-threatening high voltage of the battery system 2 in substantially harmless individual voltages of the individual battery modules 4 was reduced by disconnecting the serial interconnection.

Further referring to 2a Figure-c illustrates exemplary embodiments of the array of separators according to the present invention.

2a shows an exemplary section of battery system 2 with two battery modules 4 , The serial connection of the battery modules 4 is in 2a clearly visible. In 2a are separating elements 6 exemplarily inside a battery module 4 arranged, thus inside its sealed housing. In the housing of a battery module 4 are exemplified six battery cells arranged, which are also connected in series and together the voltage of a battery module 4 , for example, provide 12V or 24V. The control lines for triggering the separating elements 6 are in 2a shown schematically entering the housing.

2 B differs from 2a essentially only in that the dividing elements 6 outside the individual battery modules 4 are arranged. The battery modules 4 thus essentially correspond to conventional battery modules, wherein the serial connection between two battery modules 4 by a guide element with an inventive arrangement of a separating element 6 is trained. According to 2 B Already existing battery systems can be used 2 Simply retrofit according to the invention, wherein, of course, the control of the separating elements 6 must be implemented.

2c shows an example of an embodiment of a conductor element 20 with a separating element 6 , For example, at one end of the conductor element 20 , provided with an eyelet 22 for screw connection to a battery module 4 , for example, can be mounted in a housing in the cable element 20 , a separator 6 be provided, which in turn is suitably controllable, in order to separate the conductive connection in an accident case. Such cable elements can be used for (retrofitting) conversion of a conventional battery system.

Claims (7)

Battery system ( 2 ) for a vehicle, comprising at least two battery modules ( 4 ); the battery modules ( 4 ) are connected in series; characterized in that the battery system ( 2 ) further comprises a separating element ( 6 ); the separating element ( 6 ) in series between the battery modules ( 4 ) is arranged; the separating element ( 6 ) is arranged to provide a substantially lossless conductive connection in a regular operation of the vehicle; and wherein the separating element ( 6 ) is set up such that, in the event of an accident, the conductive connection between the battery modules ( 4 ), in particular non-reversible, is interruptible. Battery system according to claim 1, wherein the separating element ( 6 ) as a non-reversible electromechanical separator ( 6 ) or non-reversible pyrotechnic separating element ( 6 ) is trained. Battery system according to one of the preceding claims, wherein the separating element ( 6 ) with a control device ( 8th ) of the vehicle can be coupled, in particular with a safety control unit or airbag control unit, and by the control unit ( 8th ) receives information regarding an accident event or a triggering signal; the separating element ( 6 ) breaks the conductive connection based on the information or by means of the trigger signal. Battery system according to one of the preceding claims, wherein the battery modules ( 4 ) have a substantially hermetic sealing or insulating housing; and wherein the separating element is seconded in the housing of at least one battery module or in a conductor element between two battery modules. Battery system according to one of the preceding claims, further comprising a display element ( 16 ), which is arranged, in particular non-reversible, to indicate that the conductive connection between the battery modules ( 4 ) is interrupted. Battery system according to one of the preceding claims, comprising a plurality of series-connected battery modules ( 4 ), which together provide an operating voltage for driving the vehicle; wherein between each two serially interconnected battery modules ( 4 ) a separating element ( 6 ) is arranged; wherein in an accident event, the conductive connections between the battery modules are separable, so that the operating voltage in a number of battery modules corresponding number of individual voltages can be divided, in particular in individual voltages of 24V maximum. Vehicle, in particular electric or hybrid vehicle, comprising a battery system ( 2 ) according to one of the preceding claims.

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