WO2017036467A1

WO2017036467A1 - Method and bridging unit for selectively short-circuiting a secondary battery

Info

Publication number: WO2017036467A1
Application number: PCT/DE2016/100404
Authority: WO
Inventors: Peter Lell
Original assignee: Peter Lell
Priority date: 2015-09-04
Filing date: 2016-09-02
Publication date: 2017-03-09
Also published as: DE102015114894A1; DE102015114894B4

Abstract

The present invention relates to a method for selectively short-circuiting a secondary battery, in particular in the case of a short circuit in an external current path which is fed by the secondary battery, wherein the electrical connections of the secondary battery are electrically bridged by a bridging unit, wherein the bridging unit comprises a short-circuiting switch which can be switched over from a disconnecting position to a conducting position, and wherein the bridging unit, when a short-circuiting switch is in the conducting position, has a load resistance RLoad between the electrical connections of the secondary battery, which load resistance is below the internal resistance R of the secondary battery. The invention further relates to an electrical circuit comprising a secondary battery and a bridging unit which is suitable for implementing the method, and also to a bridging unit of this kind. The method according to the invention and, respectively, the bridging unit according to the invention and the electrical circuit according to the invention have the advantage that, in the event of selective discharging of the secondary battery by means of the bridging unit, the electrical load on the battery is kept in a range in which overheating and the possibility of the secondary battery catching fire as a result are avoided.

Description

Method and bridging unit for targeted shorting

a secondary battery

The present invention relates to a method for selectively short-circuiting a secondary battery using a bridging unit for connecting the terminals or poles of the secondary battery and a bridging unit suitable for this purpose. Furthermore, the invention relates to an electrical circuit with such a bridging unit. The method according to the invention or the bridging unit according to the invention and the circuit according to the invention have the advantage that, when the secondary battery is discharged via the bridging unit, no ignition of the secondary battery occurs.

In electric and hybrid vehicles are used as energy sources secondary batteries, in particular lithium batteries or lithium-ion batteries. A common problem with such secondary batteries is that they tend to overheat in the event of a short circuit, so that they can ignite and the secondary battery fires. It inevitably ignited the neighboring cells, which also results here in a battery fire, which can lead to the explosion of the cell, possibly even with undesirable thrust development.

In order to prevent short circuits in secondary batteries, especially in vehicle accidents, so-called disconnectors are installed in the circuits, which interrupt the circuit in an accident or as needed and thus prevent a short circuit of the secondary battery. Since secondary batteries for electric and hybrid vehicles usually have battery terminal voltages between 600V and 1300V, such circuit breakers are not always reliable units to interrupt the circuit, since at such high voltages can cause arcing within the circuit breaker, which ultimately lead to the current from the battery can not be safely interrupted in the event of a short circuit. In extreme cases, even the circuit breaker can be set on fire or explode. Furthermore, in the case of an accident of a motor vehicle, for example, there may be defective locations in the wiring harness, which may have any possible load resistance for the battery in the case of the formation of multiple arcs in the wiring harness and between the wiring harness and the chassis or ground. If the load resistance applied to the electrical connections of a battery is substantially equal to the internal resistance of the battery, it will develop its optimum performance while maximally heating up. The temperature within the battery may rise to the ignition temperature of the battery materials - ie, the case materials and / or the electrolyte - causing the battery to ignite and catch fire. Modern secondary batteries, such as lithium batteries or lithium-ion batteries, as used in electric and hybrid vehicles, but also lithium polymer batteries, may be designed so that they are intrinsically safe in the short circuit of the electrical connections of the battery. This can be achieved in that after a short circuit, although initially a high, but only very short current peak and then a lower discharge current occurs until the energy of the battery is exhausted. In conventional secondary batteries for electrically driven cars, the current peak between about 10kA and 40kA and the discharge current only in the range of about 1 kA to 7kA. This discharge current, which is lower by about one order of magnitude, can be maintained over a longer period of time (for example several or many minutes), depending on the energy content of the battery, but during the entire discharge time there is no heating of the battery cells until their ignition. A burn of the battery cells and thus a burn of the whole battery and an associated endangerment of the environment is thus safely avoided.

Since the reliability of circuit breakers (circuit breakers) can not always be ensured by the possible formation of arcs, there is a great need for an additional backup option, which ensures that secondary batteries can not ignite in the wiring harness or in the current supplied by the battery secondary circuit ,

It was therefore the object of the present invention to provide a method for the targeted short-circuiting of a secondary battery or a method for implementing the method. In particular, in the case of an undesirable short circuit in the outer current path fed by the secondary battery, for example in the case of an electric or hybrid vehicle accident, the secondary battery can be selectively short-circuited without This is heated to an impermissibly high temperature, so that the associated risk of ignition and burning of the secondary batteries is largely reduced or completely avoided.

The invention achieves this object by means of a method for selectively short-circuiting a secondary battery or a bridging unit suitable for this purpose and an electrical circuit having such a bridging unit with the features of patent claims 1 or 13 and 11.

According to the method according to the invention for selectively shorting a secondary battery, the electrical connections of the secondary battery are electrically bridged with a bridging unit, wherein the bridging unit has a load resistance R _L ast, which is below the internal resistance R, the secondary battery. In this case, the load resistance R _Las t of the bridging unit preferably approaches 0, but is preferably in the range of 0 <R _Las t <R 1.

If the load resistance R _Las t is smaller than the internal resistance R, the secondary battery, the secondary battery can not deliver the maximum possible power and the heating of the battery cells is therefore limited. In this way, there is a strong reduction in the risk of ignition of the secondary batteries, since operation during power adjustment, ie at RLast - Ri is avoided.

The term "targeted short-circuiting" is understood to mean a desired short-circuit of the secondary battery, which is performed by bypassing the two terminals of the secondary battery with the bridging unit, Preferably, the targeted short-circuiting is performed when a short circuit already occurs in the outer current path fed by the secondary battery is. A secondary battery is a rechargeable accumulator for electrochemical-based electrical energy, also called an accumulator.

The external current path fed by the secondary battery is understood to mean the current path which the battery feeds independently of the current path of the bridging unit.

The load resistor Ri.ast is generally understood to mean the electrical resistance with which the secondary battery is loaded. The load resistance Ri_ast of the bridging unit is understood to mean the resistance which the current path of the bridging unit has between the two terminals of the secondary battery. In this case, the bridging unit is defined to start at the first terminal of the secondary battery and terminate at the second terminal of the secondary battery, in other words, the bridging unit connects the two terminals of the secondary battery, and the load resistance Ri_ast of the bridging unit is thus the entire resistance of this unit (FIG. without another external load resistance) between the terminals of the battery, ie in particular not only the resistance of a single component of the bridging unit.

Under the internal resistance R, according to the invention, the design-related loss factor is understood in the interior of the battery. At this falls under load of the battery with an external electrical load, a voltage U, and the terminal voltage of the battery decreases accordingly, although the source voltage U ₀ remains constant inside the battery itself.

The size of the internal resistance is not constant in real running batteries, but is dependent on the load current, the charge or discharge of the battery, ie the respective state of chemistry of each battery cell, the temperature of the individual battery cells, the age of the battery cells, that is, the general state of the battery cell chemistry, the materials and electrolytes used, their purity and processing, and the structure of the battery cells and their internal interconnection. The load resistance Ri_ast of the bridging unit according to the invention is preferably at least 10%, most preferably at least 90%, below the internal resistance R, of the secondary battery. In addition, the load resistance Ri_ast is preferably greater than 0.

In a further embodiment of the method according to the invention, it is preferred that the total load resistance Rcesamtiast, which results from the load resistance of the bridging unit and the external load resistance R _L of the external current supplied by the secondary battery is less than the internal resistance of the secondary battery. In this case (and also quite generally for the purposes of this invention), the current path fed by the secondary battery is defined to start at the first terminal of the secondary battery and terminate at the second terminal of the secondary battery; in other words, the current path supplied by the secondary battery connects the current path both terminals of the secondary battery. The load resistance of the bridging unit is again defined as described above.

In the case of secondary batteries for cars driven purely by electricity or by means of a hybrid drive, the internal resistance R 1 of suitable secondary batteries may, for example, be in the range of 3 mQ. If the external load resistance R _L , ie the load resistance of all consumers connected to the battery (or the bridging unit) (including the line resistances), also in this area in case of accidents with cable damage, ie in an area in which there is power adjustment to a strong warming and possibly ignition of the secondary battery. The load resistance Ri_ast of the bridging unit is therefore chosen according to the invention in a secondary battery with an internal resistance in the range of 3 mQ less than 3 mQ, preferably less than 2 mQ and most preferably in the range of greater than 0 mQ and less than or equal to 2 mQ. A correspondingly low load resistance is usually made possible by all materials with good electrical conductivity.

In a further embodiment of the method according to the invention, the bridging unit preferably has a short-circuit switch. The short-circuit switch can be transferred from a disconnected position to a reference position. In the Disconnect position, the electrical connections of the secondary battery no electrical contact via the bridging unit. In contrast, in the control position, the electrical connections of the secondary battery make electrical contact via the bridging unit. In the method according to the invention, it is preferred that the short circuit switch is transferred from a disconnected position to a reference position in the case of the short circuit mentioned above.

The short circuit switch may further comprise a sensor, such as wire or fiber optic or PVDF sensor, which is preferably arranged so that the sensor is destroyed or crushed or cut at a transition of the short-circuit switch from the disconnect to the switching position, without the would interfere with the shorting process or bridging the terminals of the secondary battery. Such a sensor offers the possibility of detecting whether the bridging has actually taken place.

The shorting switch preferably includes a first and a second contact, wherein each one of the contacts is connected to one of the terminals of the secondary battery.

The short-circuit switch preferably contains as switching element an electrically conductive switching piston, an electrically conductive membrane or an electrically conductive contact plate.

The switching element is subjected to a movement during the transition from the disconnected to the switching position of the short-circuiting switch, wherein two contacts of the short-circuiting switch are connected to each other, whereby the electrical connections of the secondary battery are bridged.

In the case of the electrically conductive switching piston as a switching element, it is preferred that in the disconnected position of the switching piston is connected to a first contact of the short-circuit switch and hits a movement of the control piston along its axis to a second contact of the connection switch and thus a connection between the first and the second contact of the short-circuit switch. provides. The switching piston can be solid in its material, but it can also be hollow inside, so that its mass is much smaller and can be accelerated faster than without excavation, with a short circuit is reached faster. The cavity in the piston may be filled with a lighter material, for example, polyethylene or polyoxymethylene, or polystyrene, in order to keep the void volume for the activatable drive as small as possible. As a result, propellant charge powder is saved and at the same time the switching piston can be accelerated faster and at higher speeds by the nevertheless higher combustion chamber pressure. This leads to a faster achieved short circuit.

In the case of an electrically conductive membrane as a switching element, it is preferred that in the disconnected position, the electrically conductive membrane is connected to a first contact of the short-circuit switch. For the transfer of the short-circuit switch in the switching position, the membrane is preferably moved or expanded in a direction in which there is a second contact of the short-circuit switch. From a certain strain or movement size of the membrane, this is connected to the second contact of the short-circuit switch. In this way, current can flow through the shorting switch.

In the case of an electrically conductive contact plate as a switching element of the short circuit switch, the contact plate itself is preferably not connected to any of the two contacts of the short circuit switch in the disconnected position. To transfer the short-circuit switch in the Leitstellung the contact plate is simultaneously moved to the electrical contacts and connected to them. In this way, current can flow between the two contacts.

In the case of using a contact plate as a switching element, for example, the contact plate may comprise two contact pins, and the two contacts may be configured as multi-contacts (multi-contact sockets), so that in the switching position, the contact pins of the contact plate are introduced into the contact-side multi-contacts. Conversely, the contact plate can also have multi-contacts, and the contacts themselves can be designed as contact pins, which are then inserted or retracted in the switch position into the plate-side multi-contacts. In a further embodiment it is preferred that in the method according to the invention, the bridging unit or the external current path fed by the secondary battery has a circuit breaker as a fuse element in the case of a short circuit in the external current path. It is preferred that the electrical connections of the secondary battery are then electrically bridged with the bridging unit when the circuit breaker does not turn off the current in the current path. The triggering of the short-circuit switch from the disconnected position to the control position, can be made for example by a control unit. The control unit may be any conceivable control unit, for example, it may be a control unit, as used in the deployment of airbags. The control unit preferably also triggers a transition of the disconnector from the Leitstellung in the disconnected position.

The short-circuit switch of the bridging unit can also be used to support a circuit breaker by short-circuiting the short-circuit path of the bridging unit and thus briefly allows the discharge current of the battery to flow over the short-circuit path as far as possible. As a result, the contacts of the circuit breaker can be opened without an arc. Shortly after opening the circuit breaker then reached by the bridging unit short circuit of the battery connections can be completely or partially canceled, for example, to protect the battery and not heat further. It is also sufficient to close the short-circuit path at the same time or within a small time span of a maximum of about 1 to 1.5 ms after opening the circuit breaker, since in this short period of time an arc can not develop stably and would be deleted immediately.

Also, you can only take so much power through the choice of a suitable piston or contact plate material with a higher electrical resistivity, that the residual current through the circuit breaker at the moment of opening the contacts no arc is pulled or the still forming arc forms only weak and can be deleted sufficiently well in the circuit breaker. Preferably, the movement of the switching element will be effected by an activatable drive.

The activatable drive may be an inductive drive, an eddy current drive, a pin puller drive or a gas pressure drive, wherein in a gas pressure drive, the gas pressure is generated by means of a gas generating material, in particular by the combustion or oxidation of a liquid and / or solid gas generating material, in particular an activatable pyrotechnic gas-generating material. Such activatable drives have the advantage that the bridging can be done with the specified load resistance below the internal resistance within a very short time, and thus heating or a heat increase in the secondary battery is prevented.

In an inductive drive, an induction coil may be provided at a suitable distance from the switch housing. The switching element may be suitably designed to be magnetic. The switching element can also be equipped with an induction coil. It would also be conceivable to equip the switching element with an induction coil and to provide an electromagnetic reference point at a suitable distance from the switching element, for example a permanent magnet. In this way, the switching element can therefore be moved alternatively or additionally inductively.

If the activatable drive is embodied as a forced-current drive, it preferably has a force coil, which is flowed through from outside for the desired switching by means of a surge current. For this purpose, the switching element is preferably made of a highly electrically conductive material, whereby a current is induced by the surge current in the force coil, which is opposite to the exciting current in the force coil according to Lenz's rule, whereby the switching element repelled by the force coil extremely fast and with high force is tearing off while the connected in the housing sections of the connecting elements.

Wrd made the movement of the switching element by gas pressure, it is preferably transmitted to the switching element and thereby moved. Such a gas pressure can be generated pyrotechnic or be constructed by suitable gas lines. If the gas pressure is generated pyrotechnically, then it is expedient to provide a combustion chamber located in the interior of the drive housing with incorporated propellant charge powder which can be activated by means of a firing or priming piece. As propellants, however, in addition to propellants and liquid or gaseous fuels and oxidizers are used, which can be injected for example in the combustion chamber, which is preferably integrated into the switch. Such fuels and oxidizers are referred to below as gas-generating materials. The pyrotechnic gas-generating materials, regardless of whether they react deflagrating or detonatively, should also be encompassed by this. After the activation of the combustion or oxidation process, these gas-generating materials generate a gas pressure (or, in the case of already gaseous fuels and / or oxidizers, a gas pressure which is markedly higher than the initial state), which acts on the drive piston and the disengagement element connected thereto and the switch from the guide position moved to the disconnected position. For ignition, a spark plug, a glow wire or a lighter can be used. Alternatively or additionally, the combustion chamber could already contain either fuel or oxidizers (in liquid, solid or gaseous form). In order to provide a pyrotechnic generation of gas pressure and thus the pyrotechnic triggering of the switch, only a pyrotechnic mixture must be inserted into a combustion chamber. At the desired time, this can then be ignited by an ignition or igniter.

Alternatively or additionally, the combustion chamber can also be equipped with a firing or priming piece. In a suitably chosen ignition or ignition piece enough gas and / or exhaust products can be generated at its ignition, so that builds up a sufficient pressure in the combustion chamber. This can then move over an end plate, which is also referred to as a release plate acting as a sabot, the switching element a sufficiently large piece to be connected to the contact or the contacts of the short-circuit switch. If the pyrotechnic triggering of the switch is provided via a combustion chamber, then the rotation of the combustion chamber can be increased by introducing filler bodies into the combustion chamber. Such fillers can remove the unneeded empty volume. Reduce men in the combustion chamber, so that an already much smaller amount of gas applied to the movement of the sabot and thus the switching element required pressure.

A pin-puller drive is understood to mean a drive which does not move the switching element in an urging manner into the conducting position of the connecting switch but by pulling.

An electrical circuit according to the invention comprises a secondary battery and a bridging unit, which is connected to an external current path with an electrical load, wherein the bridging unit has a current path for bridging the electrical connections of the secondary battery, in which a targeted triggering short-circuit switch is provided from a disconnected position into a Leitstellung, and wherein the current path of the bridging unit in the Leitstellung the short-circuiting switch has a load resistance R _Las t, which is lower than the internal resistance R, the secondary battery, wherein the targeted triggering of the short-circuiting switch preferably in the case of a short circuit in the outer current path takes place.

The electrical load may be any electrical or electronic device or unit that can be operated by the or another secondary battery.

The bridging unit may additionally comprise a disconnect switch for disconnecting the outer current path that can be transferred from a conducting position to a disconnected position, wherein the disconnecting switch and the short-circuiting switch are preferably designed as a single structural unit in the form of a short-circuiting / disconnecting switch, and wherein the disconnecting switch and the shorting switch are preferably are configured or controllable, that the method according to one of the claims 3 to 5 is executed.

The bridging unit according to the invention or the electrical circuit according to the invention can additionally comprise a control unit for transferring the short-circuit Switch from the disconnected position in the Leitstellung and / or for transferring the disconnector from the Leitstellung in the disconnected position. The control unit may be any conceivable control unit, for example, it may be a control unit, as used in the deployment of airbags.

The present invention also relates to a bridging unit designed as a short-circuiting / disconnecting switch, wherein

(a) the shorting / disconnecting switch can be transferred from a first position to a second position,

(b) the shorting / disconnecting switch comprises a housing, a first contact, a second contact, a third contact, a movable in the housing release element and at least one connecting element, in the first position of the switch, an electrical connection between the third contact and the makes second contact,

(C) the housing has an inner space surrounding the at least one connecting element, and

(D) at least one connecting element is attached at one end to the base side of the housing and at the other end to the disengaging element in the interior of the housing, and

(e) the short-circuiting / disconnecting switch is designed so that a mechanical movement of the disengaging element can transfer the switch from the first position to the second position, wherein the disengagement element acts mechanically on the at least one connecting element extending in the interior such that the electrical connection between the third contact and the second contact at at least one separation point of the connecting element is interrupted, and thereby a connection between the first and the second contact is formed, preferably characterized that the release plate is electrically conductive and connects the first and the second contact.

According to the invention, the short-circuiting / disconnecting switch can be designed such that, by a mechanical movement of the disengaging element, it first completely or partially short-circuits the battery terminals and shortly afterwards begins to disconnect the external circuit.

Furthermore, the short-circuiting / disconnecting switch can also be designed such that, after the opening of the external circuit, the complete or partial short-circuit path of the battery is completely or partially opened again.

The bypass unit with such a shorting / disconnecting switch may have a certain electrical (non-zero) resistance in the short circuit path that is small enough to make the current flowing in the short circuit path when the switch is closed so large that the current in the external circuit is high is so low that, when the outer circuit is cut, arcing is prevented or weakened sufficiently and yet is so high that it can continue to bypass the battery terminals without the battery cells being overheated by the short-circuit current.

The short-circuiting / disconnecting switch according to the invention may also have two or more connecting elements between the base side and the disengaging plate, which connect the second and the third contact either electrically in parallel or electrically in series.

The short-circuiting / disconnecting switch (switch) according to the invention is preferably used for interrupting a first current path fed by a secondary battery and bypassing the two terminals of the secondary battery in a second current path. In this case, the first terminal of the secondary battery is preferably connected to the first and the third contact of the switch, and the second terminal of the secondary battery is preferably connected to the second contact of the switch. In other words, the switch according to the invention is preferably used in the invention. in accordance with the method, the uses according to the invention or the device according to the invention.

The switch according to the invention can also have an activatable unit, as described above.

All definitions and preferred embodiments and their constituents listed in connection with the first-mentioned method according to the invention for preventing the ignition of a secondary battery preferably also apply to the further objects, embodiments, methods or devices according to the invention. This also applies vice versa.

Other features, but also advantages of the invention will become apparent from the following drawings and the accompanying description. In the figures and in the accompanying descriptions, features of the invention are described in combination. However, these features may also be included in other combinations of an article of the invention. Each disclosed feature is thus also to be regarded as disclosed in technically meaningful combinations with other features. The illustrations are partly slightly simplified and shown schematically.

Fig. 1a: shows a short-circuit switch with a switching piston as a switching element in the disconnected position;

Fig. 1 b: shows the short-circuit switch of Figure 1a in the Leitstellung.

FIG. 2a shows a short circuit switch with an electrically conductive membrane in the disconnected position; FIG.

Fig. 2b: shows the short circuit switch of Figure 2a in the Leitstellung.

Fig. 3a: shows a short-circuit switch with a contact plate as a switching element in the disconnected position; Fig. 3b: shows the short-circuit switch of Figure 3a in the Leitstellung.

4a shows a short-circuit switch with a contact plate as a switching element with a pin-puller drive in the disconnected position;

Fig. 4b: shows the short-circuit switch of Figure 4a in the Leitstellung.

Fig. 5a: shows a short-circuit switch with a contact plate as a switching element with contact pin in the disconnected position;

Fig. 5b: shows the short-circuit switch of Figure 5a in the Leitstellung .;

6a shows a short-circuit switch with a connection plate with contact-plate-side multicontacts in the disconnected position;

Fig. 6b: shows the short circuit switch of Figure 6a in the Leitstellung.

Fig. 7a shows a short-circuit / disconnect switch according to the invention in a first position, which allows the simultaneous interruption of a first current path with the connection of a second current path, wherein the separation of the first current path is made possible by the interruption of two serially connected connection elements;

Fig. 7b shows the switch of Fig. 7a in a second position;

Fig. 8a shows a short-circuit / disconnect switch according to the invention in a first position, which allows the simultaneous interruption of a first current path with the connection of a second current path, wherein the separation of the first current path is made possible by the interruption of four serially connected connection elements;

FIG. 8b shows the switch of FIG. 8a in a second position; FIG. Fig. 9a: shows a short-circuit / disconnect switch according to the invention in a first position, the simultaneous interruption of a first

Allows current paths with the connection of a second current path, wherein the separation of the first current path is made possible by the interruption of two parallel connection elements;

Fig. 9b shows the switch of Fig. 9a in a second position; and

Fig. 10 shows a schematic diagram of a device for avoiding the ignition of a secondary battery with a short circuit / disconnect switch according to the invention.

For a better understanding of the invention, the principle underlying it will first be explained below with reference to FIG. 10.

The block diagram in FIG. 10 shows a secondary battery 200 to whose battery terminals a bridging unit 202 is connected, each having a first input port 204 and a second input port 206. First and second output ports 208, 210 of bridging unit 202 are connected to an external circuit, which is shown as an external load resistor R _L. Of course, the external load resistance R _{L may be formed} by any electrical load or by any interconnections of several electrical loads.

The secondary battery 200 may be, for example, a drive battery of an electrically operated vehicle, in particular a passenger car. For this purpose, short-circuit proof lithium batteries, for example lithium-ion batteries, are preferably used, which have an internal resistance in the range of a few milliohms.

The bridging unit 202 has in the illustrated embodiment both a series-connected to the external load resistor R _L isolation switch 212, which is closed in the illustrated initial state, as well as a short-circuit switch 214. The short-circuit switch 214 is in a short circuit path, which connects the first and second input ports 204, 206 of the bridging unit 202. In this short-circuit path, there is further provided a load resistor R _Las t which is connected to the battery poles of the secondary battery 200 upon closing the short-circuiting switch 214 opened in its initial state. In practical embodiments, the load resistor R _{L will} preferably be integrated into a corresponding device or unit which implements the switch 214.

As described below, the shorting switch 214 and the disconnecting switch 212 may also be formed as a unit, wherein the opening of the disconnecting switch 212 and the closing of the shorting switch 214 may be substantially simultaneous or at very short time intervals.

The switches 212, 214 may be designed so that they are transferred from their initial state into the respective other switching position when the external load resistance R _L falls below a certain value or the load current flowing through the external load resistance R _L exceeds a predetermined value. For this purpose, a control unit 216 may be provided, which controls the switches 212, 214 in a suitable manner, also with regard to a time sequence of the switching operations. The control unit 216 may also have one or more sensors which detect triggering events that are to lead to switching operations of the switches 212, 214. For example, a sensor may be designed such that it detects the current intensity in the outer current path, so that the control unit 216 can trigger necessary switching operations when a predetermined value is exceeded.

Of course, the control unit 216 may also be provided outside the bridging unit 202. Likewise, the sensors can also be realized outside the control unit, in particular also inside switch units, which realize the disconnect switch 212 or the short-circuit switch 214. The control unit 216 is not absolutely necessary if the switches 212, 214 are designed so that they each react independently to a specific event, which makes a switching operation required. According to the principle underlying the invention, a bridging unit has at least the short-circuit switch 214 shown in FIG. Exceeds the current in the external circuit through the external load resistor R _L a predetermined value, the short-circuit switch 214 is transferred to its closed position. As a result, the load resistance Ri_ast of the bridging unit 202 is connected to the battery poles or connected in parallel to the external load resistance R _L.

The resistance value of the load resistor R _L is chosen to be smaller than the internal resistance R, the secondary battery 200. This ensures that in each case, the parallel connection of the two windings R _Las t and R _{L has} a total resistance Rcesamtiast which is smaller than the internal resistance R, the secondary battery 200. Thus, a load on the secondary battery 200 is avoided with a load that corresponds to the internal resistance substantially or with only impermissibly small deviations. An operation in power matching is therefore avoided, whereby ignition of the battery cells and burning of the battery cells or the entire of the battery 202 is avoided.

If the bridging unit 202 also has a circuit breaker 212 as shown in FIG. 10, in addition to bridging the battery poles of the secondary battery 200 by means of the load resistor R _load, the external circuit R _{L may be} disconnected from the secondary battery 200 become.

If the operation of the short-circuiting switch 214 and the disconnecting switch 212 is substantially simultaneous or at short intervals, the generation of an arc between the contacts of the disconnecting switch 212 can be prevented. If the separation of the contacts of the circuit breaker 212 takes place after the short-circuiting of the battery poles by means of the short-circuit switch 214, the occurrence of an arc is prevented from the outset. If the operation of the circuit breaker 212 shortly after the actuation of the short-circuit switch 214, an arc is formed between the contacts of the circuit breaker 212 immediately deleted. Short-circuiting must be carried out within a period of approx. 1 to 1.5 ms in order to prevent the arc from forming stably. If the bridging unit 202 has both a disconnecting switch 212 and a short-circuiting switch 214, then the short-circuiting switch can also be opened again after disconnecting the outer current path by means of the disconnecting switch 212. In this way, the secondary battery can be spared and will not be constantly discharged. In particular, a harmful to the battery deep discharge is avoided.

For this purpose, the short-circuit current path between the two input ports of the bridging unit 202 can be separated again. This can be done either by means of a short-circuit switch 214, which can be transferred again from its closed working position to its open position or by means of a second, not shown in Fig. 10 further disconnector, which with the short-circuit switch 214 and the load resistor R _Las t in series is switched, that is in the short circuit path. This further circuit breaker can also be controlled via the control unit 216 so that the desired timing results, so first the disconnector 212 and the short-circuit switch 214 actuated substantially simultaneously (or first the short-circuit switch 214 and delayed release of the switch 212 actuated) and then the further disconnector in the short circuit path are actuated.

In the following, a number of embodiments for short-circuit switch 214 or disconnector 212 or combinations thereof will be explained in more detail with reference to FIGS. 1 to 9. In the figures 1 to 9, the terminals for the respective switch, as well as in Fig. 10, denoted by the reference numerals A to D, wherein the respective contacts A, B and C, D in the embodiment in Fig. 10 with the Input ports 204, 206 and the output ports 210, 208 of the bridging unit 202 are identical.

1 a shows a short-circuiting switch (in the following, the short-circuiting switch 214 in FIG. 10 is also referred to as a short-circuiting switch) with a switching piston 1, which can be designed, for example, as a stable contact finger. The shorting switch has an electrical contact 2 which is connected to a first terminal of the secondary battery. Furthermore, the short-circuit switch also has an electrical see contact 1 1, which is connected to the second terminal of the secondary battery. The electrical contacts 2 and 1 1 are held at a fixed distance from the housing 3, which connects the electrical contacts 2 and 1 1 firmly. The electrical contact 11 is electrically connected in the short-circuit switch with the electrical control piston 1. The switching piston 1 is movable in the direction of its extension axis and is in this case surrounded by the electrical contact 1 1, that this leads the control piston 1. The switching piston 1 is preferably conically shaped at its tip, so that it can retract accurately into a preferably narrowing section of the electrical contact 2. As a result, the control piston is injected directly into the electrical contact 2. Alternatively, however, he can also enter there in a commercial multi-contact. The contact 2 can also be carried out so that the control piston 1 digs during his flight here and so makes a good contact with the electrical contact 2. Due to the custom-fit design of electrical contact 2 and electrical contact 1 1, a direct welding of the control piston with the two contacts 2 and 11 can be achieved. The switching piston 1 has at its end facing away from the electrical contact 2 preferably a piston-side latching / Wegbegrenzung, which is preferably carried out in the form of a thickening of the piston. Similarly, the electrical contact 11 at the end of his leadership for the switching piston 1 on a piston-side latching / Wegbegrenzung 6, which is preferably designed as a constriction of limited by the electrical contact 1 1 piston shaft. 1a shows the short-circuiting switch of FIG. 1a in its conducting position, in which the piston-side latching 7 of the piston 1 has arrived at the catch 6 and is firmly pressed into the electrical contact 11, as shown by reference numeral 9. Reference numeral 10 shows how the switching piston 1 in the receiving bore for the accelerated piston, preferably tapered firmly pressed. The short-circuiting switch according to FIGS. 1 a and 1 b has an actuatable drive 4, preferably in the form of a gas generator, which is capable of bringing the switching piston from the disconnecting position to the switching position upon activation. If the short-circuiting switch is in the switching position (FIG. 1 b), a gas-filled space 8 is created between the activatable drive 4 and the switching piston 1, which space is created after activation of the activatable drive 4. Instead of in Fig. 1a and Fig. 1 b drawn gas generator as activatable drive 4 can also be a finished force element occur, wherein before the control piston 1 no gas cushion would be built. In this case, the control piston 1 or the diaphragm of the force element could then push the control piston 1 and thus accelerate. The force element can also be closed by a concertina-like folded membrane. Conceivable here would be the acceleration of the control piston 1 by impulse transmission, for example, if there is a distance greater than 0 mm between the piston compensating surface of a force element and the piston underside. In this case, the smaller control piston or the diaphragm of a force element would first be accelerated to almost or to final speed and then impinge on the control piston 1 and thus transmit its previously reached impulse to the control piston 1. With optimal design of power element piston and control piston 1 so that the switching time would be further reduced. The free distance between a force element and the control piston 1 is preferably at a distance between 1 mm and 10 mm with regard to the intended short switching time.

The short circuit switch, as shown for example in FIGS. 1 a and 1 b, may further comprise a sensor, for example wire or fiberglass or PVDF sensor, which is preferably arranged so that the sensor at a transition of the short-circuit of the disconnector is destroyed or crushed without disturbing the shorting operation of the secondary battery terminals. In a connecting element according to FIGS. 1a and 1b, such a sensor would be located, for example, in the receiving bore 5. Such a sensor could also be guided by a transverse bore in the electrical contact 2 and be destroyed by the retracting control piston 1. In order to increase the cutting action of the retracting control piston 1, the front side of the control piston 1 may be formed annularly like a blade. In order to improve the welding or pressing of the control piston 1 in the electrical contact 11 and the contact resistance after retraction or pressing of the control piston 1, the control piston 1 can be executed at this point with webs parallel to the direction of flight, so that in contact with the contact-side locking 6 with the electrical contact 1 1 bring about a higher surface pressure. The same effect can be achieved when the inner surface of the electrical contact 11 at or in the vicinity of the brake point 6 or Kontaktseiti- gene latching 6 is provided with these webs, in which case the switching piston 1 preferably does not need these webs themselves. In addition, the contact-side latch 6 in the electrical contact 1 1 and / or the control piston 1 can be made slightly conical at this point to facilitate the compression by the wedge surfaces. The webs on the control piston 1 at the serving as a pressing point contact-side latch 6 and in the electrical contact 11 are also also useful to prevent a double fit through the press point and the receiving bore. In order to further improve the pressure or the contacting, the receiving bore 5 can also be equipped internally with webs / milling parallel to the direction of flight of the control piston 1, or conversely there again only the control piston 1 can be equipped with these webs parallel to the direction of flight.

2a and 2b show a short-circuit switch with a diaphragm 17 in the disconnected position of Fig. 2a and the diaphragm 19 in the Leitstellung of Fig. 2b. The short-circuit switch includes an activatable drive 18, for example a lighter, a gas generator or a detonator, in a space closed off from the electrical contact 22 and the membrane 17 to the outside. This closed space contains a fluid or gel filling 21 to reduce the void volume in the combustion chamber of the activatable drive 18 and / or the shock wave propagation between activatable drive 18 and diaphragm 17 to provide the smallest possible shock wave resistance. On the opposite side of the membrane 17 to the electrical contact 22 there is another electrical contact 20 at a certain distance. According to the invention, the contact 20 is connected to a first electrical connection of the secondary battery, the electrical connection 22 being electrically connected to a second electrical connection of the secondary battery connected is. Upon activation of the activatable drive 18 there is an expansion of the propellant contained therein, for example, so that the space surrounded by the membrane 17 and the electrical contact 22 expands and the membrane 17 is pressed against the electrical contact 20. Since the membrane 17 or the stretched membrane 19 is electrically conductive, the electrical contacts 20 and 22 are connected to each other. 3a shows the schematic representation of a short-circuiting switch with a contact plate 12 and the electrical contacts 23 and 24. The electrical contact 23 is according to the invention connected to the first electrical connection of the secondary battery, wherein the electrical contact 24 is connected to the second electrical connection of the secondary battery , In Fig. 3a, the electrically conductive contact plate 12 is not in contact with the electrical contacts 23 and 24, so that the short-circuit switch is in the disconnected position. The short circuit switch also has an activatable drive 13, which may be a force element, for example, and upon activation of a plunger / piston of the activatable drive 13, wherein the plunger / piston 14 is connected to the contact plate 12, the contact plate 12 against the electrical contacts 23rd and 24 presses. Since the contact plate 12 is electrically conductive, a connection between the electrical contacts 23 and 24 is made, whereby according to the invention a bridging of the first and the second terminal of the secondary battery takes place.

FIGS. 4a and 4b likewise show the schematic illustration of a short-circuit switch with a contact plate 12 and the electrical contacts 23 and 24. The short-circuit switch of FIGS. 4a and 4b essentially does not differ from the short-circuit switch of FIG. 3a and Fig. 3b, however, has the difference that the contact plate 12 is not pressed at the transition from the separating into the Leitstellung against the electrical contacts 23 and 24, but pulled by the designed as a pin-puller drive activatable drive 15. Again, the contact plate 12 is preferably connected to the pin-puller drive 15 via a pull rod 16 of the activatable drive 15.

3a and FIG. 3b, in each case in the disconnected position and in the conducting position, but with the difference that the contact plate 30 contains two contact pins which are precisely matching the contact-side multicontacts 26 and 27 are formed. The contact-side multi-contacts 26 and 27 are mounted on the multi-contact carriers 32 and 33. The contact-side multi-contact 26 is according to the invention with the first terminal of the secondary battery and the contact-side multi-contact 27 electrically connected to the second terminal of the secondary battery. FIGS. 6a and 6b show a connecting element similar to that shown in FIGS. 5a and 5b, in the conducting and disconnected positions, but here the electrical contacts 34 and 35 are designed as contact pins which fit exactly onto the contact plate 31 Multicontacts (plate side) are formed.

Fig. 7a and Fig. 7b show a first embodiment of a short-circuiting / disconnecting switch 1 10 according to the invention (further called only switch). This switch 1 10 has a housing 112 which may be made substantially cylindrical. The housing 112 has a base side 1 14 (left side), at which also the third contact 128 and the second contact 130, preferably isolated from each other, are present. In the interior 1 18 of the housing 112 of the third contact 128 and the second contact 130 portions of connecting elements 122 parallel to each other to the release element 124 are provided, which at the base side 114 with the third and the second contact 128, 130 and are connected to the release element 124 on the other side. The two parallel sections of the connecting elements 122 are also electrically in contact with one another along the disengaging element 124, so that the two sections of the connecting elements 122 are connected in series from the third contact 128 to the second contact 130. The second contact is guided from the base side to the side opposite the base side. The base side opposite side is composed of at least two electrically conductive parts, which are each insulated from each other. The first part is the part connected to the second contact 130. The second part is the first contact 131. The sections of the connecting elements 122 preferably have mechanical cross-sectional weakenings 123, so that when the release element 124 moves in the direction of the side opposite the base side, the sections of the connecting elements 122 break at these points. In this way, the connection between the third contact 128 and the second contact is interrupted. The release plate is preferably itself electrically conductive and is preferably moved so that it contacts the first and the second part of the opposite side of the base side of the housing. In this way, an electrical contact between the first and the second contact is made. Between the disengaging element 124 and the base side 1 14 in the interior of the housing 112 is an activatable drive 126 with a drive housing 136 and a drive piston 138 which communicates with the disengagement member 124. In Fig. 7, the activatable drive 126 is configured as a gas pressure drive, which has a combustion chamber in the interior of the drive housing 136, which presses the drive piston 138 against the release element 124 when ignited. Thus, the portions of the connecting members 122 rupture at the cross-sectional weakenings 123, and at each of the portions of the connecting members 122, separation points are caused to break the electric current flow between the third contact 128 and the second contact 130.

FIGS. 8a and 8b show a further embodiment of a switch 110 according to the invention. This switch is constructed essentially like the switch shown in FIGS. 7a and 7b, with the differences that it has four sections of connecting elements 122 and a collector 132. The portions of the connecting elements 122 connected to the third contact 128 and the second contact 130 are fastened to the base side 14 and to the disengaging element 124. These portions of the connecting elements 122 connected to the contacts are in contact with each other via two further sections of connecting elements 122, which are likewise connected to the disengaging element 123 on one side and on the other side (base side) to a collector 132, which is also the latter Portions of the connecting elements 122 electrically connects to each other. If the disengagement element 124 is moved in the direction of the side opposite the base side 14 by the activatable drive 126 in the middle of the housing, then not only, as in the embodiment of FIG. 7, two connecting elements 122 are torn off at the cross-sectional weakenings 123 but all four sections of the connecting elements 122. Such an embodiment thus increases the safety of the switch according to the invention.

FIGS. 9a and 9b show a first embodiment of a short-circuiting / disconnecting switch 110 according to the invention (further referred to as a switch). This switch 110 has a housing 112, which may be designed substantially cylindrical. The housing 112 has a base side 1 14 (left side), on which the third contact 128 is present. In the interior 118 of the housing 1 12 of the third contact 128 two sections of connecting elements 122 parallel to each other extending to the opposite side, where they are connected to the second contact 130 are. Furthermore, the connecting elements 122 are fixedly connected to the release element 124, which is also electrically conductive. The base side opposite side is composed of at least two electrically conductive parts, which are each insulated from each other. The first part is the second contact 130. The second part is the first contact 131, which is preferably located in the middle of the second contact 130. The sections of the connecting elements 122 preferably have mechanical cross-sectional weakenings 123, such that when the release element 124 moves in the direction of the side opposite the base side, the sections of the connecting elements 122 break at these locations. In this way, the connection between the third contact 128 and the second contact is interrupted. The release plate is preferably itself electrically conductive and is preferably moved so that it contacts the first and the second part of the opposite side of the base side of the housing. In this way, an electrical contact between the first and the second contact 130, 131 is produced. Between the disengaging element 124 and the base side 1 14 in the interior of the housing 112 is an activatable drive 126 with a drive housing 136 and a drive piston 138, which is in communication with the disengagement element 124. 9, the activatable drive 126 is designed as a gas pressure drive, which has a combustion chamber in the interior of the drive housing 136, which presses the drive piston 138 against the release element 124 when it is triggered. Thus, the portions of the connecting members 122 rupture at the cross-sectional weakenings 123, and at each of the portions of the connecting members 122, separation points are caused to break the electric current flow between the third contact 128 and the second contact 130.

All the switches according to FIGS. 7 to 9 can also be designed so that their connecting elements at the predetermined and weakened points in cross section also melt through an increased current flow in an external short circuit via the connecting elements and thus cause a (passive) separation of the connecting elements. Thus formed switches can thus both active, ie controllable, as well as passive, ie triggered by exceeding a rated current. In addition, the switches can also be designed so that is dispensed with an active triggering and only a passive triggering is possible. This passive shutdown can be homogenized by surrounding the separation points with a priming mixture, which ignites at a certain, increased by the increased current flow temperature at these points of the connecting elements. Thus, the separation points are heated in addition or further and brought the material there faster melting than by the triggering current flow alone.

Of course, a secondary battery which is intended to be selectively short-circuited with the method or the bridging unit according to the invention must be suitable for this purpose. However, this is usually the case for all currently available, designated as intrinsically safe secondary batteries.

LIST OF REFERENCE NUMBERS

1 control piston, front and over the entire length preferably slightly tapered, with or without webs outside

2 electrical contact, connected to a terminal 1 of the secondary battery

3 housing, connects the electrical contacts of the short-circuit switch

4 activatable drive, eg. Gas generator or force element

5 Mounting hole for accelerated piston, possibly conically tapering, pressing point

6 contact-side locking / Wegbegrenzer for pistons

7 piston-side locking / travel limiter

8 gas-filled room after triggering the activatable drive 4

9 piston-side latching 7 of the piston 1 arrived at contact-side latching 6 and in this case firmly pressed into contact 11

10 piston cone in tapered bore 5 firmly pressed

1 1 electrical contact, connected to a terminal 2 of the secondary battery

12 contact plate

13 activatable drive or power element

14 plunger / piston of the activatable drive 13

15 activatable drive, eg Pin-Puller drive

16 drawbar of the activatable drive 15

17 membrane, electrically conductive

18 activatable drive, e.g. Lighter, gas generator or detonator

19 diaphragm 17, deformed after the activation of the activatable drive 18

20 electrical contact, connected to a terminal 1 of the secondary battery

21 fluid or gel filling

22 electrical contact, connected to a terminal 2 of the secondary battery

23 electrical contact, connected to a terminal 1 of the secondary battery

24 electrical contact, connected to a terminal 2 of the secondary battery

25 fluid / gel filling after triggering or passage of the shock wave generated by the activatable drive 18

26 contact multicontact 1 contact multicontact 2

Contact plate with contact pins

Contact plate with multi-contact inserts

Multi contact carrier for contact 1

Multi contact carrier for contact 2

Contact pin for contact 1

Contact pin for contact 2

Short-circuit / break switch

casing

Base side of the housing

Interior of the housing

insulator medium

fasteners

Cross-sectional weaknesses

disengagement

activatable drive

third contact

second contact

first contact

collector

drive housing

drive piston

secondary battery

bridging unit

first entrance port

second input port

first exit port

second output port

disconnectors

Short-circuit switch

Claims

claims

A method of selectively shorting a secondary battery, in particular in the case of a short circuit in an external current path fed by the secondary battery, wherein the electrical terminals of the secondary battery are electrically bridged with a bridging unit, the bridging unit comprising a short-circuiting switch which can be disconnected from a disconnected position a Leitstellung can be transferred, and wherein the bridging unit has a load resistance R _L ast between the electrical terminals of the secondary battery, which is below the internal resistance R, the secondary battery at a located in the Leitstellung short-circuit switch.

2. The method of claim 1, wherein the load resistance RLast at least 10%, preferably at least 90%, below the internal resistance R, the secondary battery is located.

3. The method according to any one of the preceding claims, wherein the bridging unit or the outer current path comprise a circuit breaker, which is transferred in the case of a short circuit in the outer current path from a closed position to an open position.

4. The method of claim 3, wherein the electrical connections of the secondary battery in the case of a short circuit in the outer current path are then electrically bridged by the closing of the short-circuit switch when the circuit breaker does not turn off the power in the outer current path.

5. The method according to claim 3, wherein in the case of a short circuit in the outer

Current path substantially simultaneously or with a small time shift, which is smaller than the time required for the occurrence of a stable arc in the circuit breaker, the short-circuit switch is closed and the disconnector is opened, or wherein in the case of a short circuit in the outer current path, the short circuit switch is first closed and then the disconnector is opened.

6. The method according to any one of the preceding claims, wherein the secondary battery is a Li-battery or Li-ion battery.

7. The method according to any one of the preceding claims, wherein the short-circuiting switch as a switching element has an electrically conductive switching piston (1), an electrically conductive membrane (17, 19) or an electrically conductive contact plate (12).

8. The method of claim 7, wherein the switching element is subjected to the transition from the disconnect to the switching position of the short-circuiting switch of a movement, thereby connecting two contacts of the shorting switch together, whereby the electrical connections of the secondary battery are bridged.

9. The method of claim 8, wherein the movement of the switching element is effected by an activatable drive.

10. The method according to claim 9, wherein the activatable drive is designed as an inductive drive, as an eddy current drive, as a pin-puller drive or as a gas pressure drive, wherein the gas pressure is generated by means of a gas-generating material, in particular by combustion or oxidation of a liquid and / or solid gas-generating material, in particular an activatable pyrotechnic gas-generating material.

1 1. An electrical circuit with a secondary battery and a bridging unit, which is connected to an outer current path having an electrical load, wherein the bridging unit has a current path for bridging the electrical connections of the secondary battery, in which a targeted triggering short-circuit switch is provided , which is convertible from a disconnected position in a Leitstellung, and wherein the current path the bridging unit in the control position of the short-circuit switch has a load resistance R _Las t, which is lower than the internal resistance R, the secondary battery, wherein the targeted triggering of the short-circuiting switch is preferably in the case of a short circuit in the outer current path.

12. An electrical circuit according to claim 11, wherein the bridging unit comprises a switchable from a Leitstellung to a disconnected position disconnector for the separation of the outer current path, wherein the circuit breaker and the short-circuiting switch are preferably configured as a single unit in the form of a short-circuit / disconnector, and wherein the circuit breaker and the shorting switch are preferably configured or controllable, that the method according to one of claims 3 to 5 is executed.

13. A bridging unit for a device according to claim 1 1, which is connectable to the secondary battery and the outer current path with an electrical load, wherein the bridging unit has a current path for bridging the electrical connections of the secondary battery, in which a short-circuit switch is provided, of a Separation position can be converted into a Leitstellung, and wherein the current path of the bridging unit in the Leitstellung of the short-circuiting switch has a load resistance R _Las t, which is less than the internal resistance R, the secondary battery.

14. Bridging unit according to claim 13 for a device according to claim 12, wherein the bridging unit has a switchable from a Leitstellung to a disconnected position disconnector for the separation of the outer current path, wherein the circuit breaker and the shorting switch preferably as a single unit in the form of a short circuit / Circuit breaker are designed, and wherein the circuit breaker and the short-circuiting switch are preferably configured or controllable, that the method is carried out according to one of claims 3 to 5.

15. Bridging unit according to claim 14, which is designed as a short circuit / disconnect switch, which can be transferred from a first position to a second position, which comprises a housing (112), a first contact (131), a second contact (130), a third contact (128), a release element (124) movable in the housing at least one connecting element (122) which establishes an electrical connection between the third contact and the second contact in the first position of the switch, wherein the housing has an inner space (118) surrounding the at least one connecting element and wherein the at least one connecting element is connected to one End is fixed to the base (1 14) of the housing and at the other end to the disengaging element in the interior of the housing, and which is designed so that a mechanical movement of the disengaging element can transfer the switch from the first position to the second position, wherein the disengagement element acts mechanically on the at least one connecting element extending in the interior, in that the electrical connection between the third contact and the second contact is interrupted at at least one separation point of the connection element, whereby a connection between the first and the second contact arises.