Patent Description:
With the advanced development of battery driven vehicles, such as electric vehicles (EV) or hybrid electric vehicles (HEV), high voltage energy storage systems become more and more common in vehicles. Nowadays, such high voltage energy storage systems are typically capable of supplying voltages in a range between <NUM> V and <NUM> kV or even higher voltages. In these HV systems, the use of contactor devices for connecting and disconnecting electronic circuits in an energy storage system is known state of the art.

Conventionally, contactor devices are capable of reversibly changing their state between a closed state, where current flow through the contactor device is possible and an open state, where current flow through the contactor device is prevented. In addition, it is known to use overcurrent protection devices, like pyro-fuses, for irreversibly break the voltage supply in the high voltage energy storage system. This is for example necessary, when an extensive overcurrent or a malfunction is detected in the electronic circuits of the energy storage system or in case that a vehicle, which is driven by the power supplied from the energy storage system, has an accident.

However, depending on applications, in which the energy storage system is used, more switching states may be desired. Especially, in a battery driven vehicle, high voltage driving batteries, which supply voltages in the range of 800V are more and more used. For providing such high voltages, a plurality of battery modules (or battery packs) are electrically connected to form the high voltage battery. However, since it was previously common to use <NUM> V as output voltage of driving batteries, many chargers or charging stations are only capable of providing charging voltages up to <NUM> V, but not higher voltages and especially not charging voltages in the <NUM> V range. For solving this problem, it is known to electrically connect two batteries (or battery strings) of the high voltage driving battery, each with an output voltage of <NUM> V, in parallel for charging, and to electrically connect the same batteries (or battery strings) in series for driving, then outputting an output voltage of <NUM> V.

However, with the above described single-pole contactor devices, at least three contactor devices are necessary for electrically connecting two batteries (or battery strings) selectively in parallel or in series. Therefore, there is a need for new switching devices, which allow for a simplified configuration for electrically connecting two batteries (or battery strings) selectively in parallel or in series.

For example, <CIT> discloses a switching device having a contact arrangement with a first contact element and a second contact element for selectively bridging interruptions of two switching paths of the switching device. The contact arrangement is moved by an actuator, in order to switch the switching device between a first switching state, in which the switching device is capable of connecting two batteries in series, and a second switching state, in which the switching device is capable of connecting two batteries in parallel.

<CIT> discloses a rechargeable battery jump starting device with a leapfrog charging system, which, for example, can sequentially charge multiple batteries of the rechargeable battery jump starting device. A control switch of a 12V/24V selective type switch can be switched by rotating a control knob to selectively connect two batteries in parallel or in series.

<CIT> discloses an electrical system of a vehicle, which comprises first and second battery sets and a selector switch, which selectively connects the first and second battery sets in parallel or in series. The selector switch includes two bus bars, which are rotatably mounted relative to a mounting plate for selectively connecting the first and second battery sets in parallel or in series.

<CIT> discloses a serial-to-parallel converting apparatus, which includes an input plate connected to positive electrodes and negative electrodes of a plurality of battery cells, respectively and an output plate spaced apart from the input plate and connected to an external terminal. A rotary plate is rotatably interposed between the input plate and the output plate to electrically connect the input plate and the output plate, wherein the rotary plate converts serial connection and parallel connection of the plurality of battery cells by rotating.

<CIT> discloses the use of a worm gear transmission in a switching device.

However, the inventors of the present inventors have found that there is still room for improvement of such a switching device, since the known switching devices have a relative complex contact configuration that result in a relatively high weight.

Accordingly, it is an object of the present invention to provide a switching device, which allows to change the connection state of a high voltage battery by using a simplified contact configuration. Furthermore, it is an object of the present invention to provide a space and weight saving as well as economic solution.

Advantageous aspects of the present disclosure are the subject matter of the dependent claims.

Examples, aspects and embodiments presented in the following and not necessarily falling under the scope of the claims are provided in the application to better understand the invention.

According to the present invention, there is provided a switching device as set forth in claim <NUM>. Further embodiments are inter alia disclosed in the dependent claims. The switching device comprises a fixed bus bar arrangement, which comprises at least a pair of fixed input bus bars and a pair of fixed output bus bars, a moveable bus bar arrangement, which comprises at least a first connection bus bar and a second connection bus bar. The switching device further comprises at least one actuation element, which is configured to change a position of the moveable bus bar arrangement at least to and from a first switching position and to and from a second switching position, wherein in the first switching position, each of the fixed input bus bars is electrically connected to respectively one of the fixed output bus bars, and in the second switching position, the pair of fixed input bus bars is electrically connected to each other, and wherein the moveable bus bar arrangement is rotated by the at least one actuation element for changing the position of the moveable bus bar arrangement.

By the introduction of the rotational movement of the moveable bus bar arrangement, the present disclosure provides a switching device for switching between two output voltage levels, with a more efficient contact configuration. This allows for a substantial reduction of weight and necessary space consumed by the switching device compared to conventional solutions. Further, it allows for lower contact resistance in the switching paths of the switching device due to a reduction of contact points, a higher mechanical safety due to an inherently avoidance of short circuits and a reduced risk for arching. Hereby, a rotation of the moveable bus bar arrangement should in particular mean a rotation around a rotational axis, which does not change the alignment of the connection bus bars of the moveable bus bar arrangement with respect to each other, but only the orientation of the moveable bus bar arrangement as a whole.

The switching device further comprises a transmission unit having at least one driven member and at least one output member, which are coupled to one another in a rotationally driving manner in a first angular range, wherein the moveable bus bar arrangement is supported on the at least one output member, and wherein the driven member is rotated by the at least one actuation element for changing the position of the moveable bus bar arrangement.

By implementing the transmission unit for transmitting the forces generated from the at least one actuation element to the moveable bus bar arrangement, the switching device allows for an efficient force transmission to drive the rotational movement of the moveable bus bar arrangement between the switching positions.

The at least one driven member applies an axial force upon the at least one output member, when the at least one driven member is driven outside of the first angular range, such that the at least one output member moves the moveable bus bar arrangement along a direction at least substantially parallel to the axis of rotation of the driven member. In this manner, it is allowed to transform the torque transmitted to the at least one driven member into an axial force, so that the torque can be used for moving the moveable bus bar arrangement in a linear movement along the direction parallel to the axis of rotation of the driven member with an efficient force transmission. This allows to reduce the friction applied on the contact points of the fixed bus bars and on the moveable connection bus bars.

According to a second aspect, a rotational movement of the at least one output member is restricted to the first angular range. In this manner, the third aspect allows for a precise positioning of the moveable bus bar arrangement in the first switching position and in the second switching position.

According to a third aspect, the at least one output member comprises a toothed hub profile, which mates with an interlocking notch profile of the at least one driven member in a form-fitting and rotationally driving manner in the first angular range, and which disengages from the toothed hub profile, when the at least one driven member is driven outside of the first angular range. Accordingly, the fifth aspect allows to enhance the efficiency of torque transmission between the at least one driven member and the at least one output member in the first angular range. In addition, it is prevented that a torque is applied by the at least one driven member on the at least one output member outside of the first angular range, so that the transmission unit can efficiently transmit the force generated by the at least one actuation element.

According to a fourth aspect, the hubs of the toothed hub profile are formed as beveled wedges. In this manner, the sixth aspect allows for a friction-reduced decoupling of the at least one output member from the at least one driven member, when the at least one driven member is driven outside the first angular range.

According to a fifth aspect, the at least one driven member is mechanically connected to a shaft structure, which transfers a torque generated by the at least one actuation element for changing the position of the moveable bus bar arrangement to the at least one driven member. Hereby, the torque may be transmitted from the at least one actuation element to the shaft structure through a gear, which can define an optimal gear transmission ratio for driving the shaft structure.

According to a sixth aspect, a housing of the switching device comprises at least one output member blocking element, which is configured to engage with at least one lug of the at least one output member for restricting the rotational movement of the at least one output member to the first angular range. Alternatively or in addition the housing of the switching device may comprise at least one driven member blocking element, which is configured to engage with at least one lug of the at least one driven member for restricting the rotational movement of the at least one driven member to a second angular range, the second angular range being larger than the first angular range. By the respective blocking elements, it is ensured that the movement range of the at least one driven member and the at least one output member is restricted in order to enhance the efficiency of the force transmission from the at least one actuation element to the moveable bus bar arrangement. Hereby, integrally forming the blocking elements within the housing of the switching device enables a space saving configuration of the switching device and allows for a simplification of the fabrication process. However, it is also possible to provide dedicated blocking elements, which could be arranged within the switching device as separated parts arranged separately from the housing.

According to a seventh aspect, the at least one output member blocking element comprises at least one asymmetrically formed guiding groove, which is designed to restrict a movement of the at least one output member to an axial movement, when the at least one driven member is driven outside of the first angular range. Accordingly, the guiding groove enables a linear dropping or lifting of the moveable contact arrangement when closing or opening the contacts between the moveable contact arrangement and the fixed bus bars of the switching device.

According to an eighth aspect, the at least one connection bus bar of the moveable bus bar arrangement is resiliently supported on the at least one output member by at least one biased spring element. This has the advantage to control the contact forces between the moveable bus bar arrangement and the fixed bus bars of the switching device, when the at least one moveable bus bar is pressed by the at least one output member onto the fixed bus bar arrangement. Further, the at least one biased spring element contributes in absorbing small dislocations or imbalances between the connection bus bars of the moveable bus bar arrangement.

According to a ninth aspect, in the first switching position, the first connection bus bar and the second connection bus bar electrically connect respectively one of the input bus bars to respectively one of the output bus bars. In this manner, the moveable bus bar arrangement allows to connect two batteries in parallel over a low resistive connection having only two contact points for each connecting path.

According to a tenth aspect, in the second switching position, the first connection bus bar electrically connects the pair of input bus bars with each other, and the second bus bar is electrically connected to at most one of the input bus bars or one of the output bus bars, and at least one contact point of the second connection bus bar is electrically isolated from the remaining bus bars of the fixed bus bar arrangement. In this manner, the first connection bus bar of the moveable bus bar arrangement allows to connect two batteries in series over a low resistive connection having only two contact points, while the second connection bus bar does not provide any electrical connection. By electrically isolating at least one contact point of the second connection bus bar, for example due to sufficient spacing from the remaining bus bars of the fixed bus bar arrangement, the generation of short or arcing in the switching device is prevented.

According to an eleventh aspect, the switching device further comprises a first input terminal, which is electrically connected to one of the fixed input bus bars, and a second input terminal, which is electrically connected to the other one of the fixed input bus bars.

According to a twelfth aspect, the at least one actuation element comprises an electric motor, which is configured to rotate the at least one driven member of the transmission unit for changing the position of the moveable bus bar arrangement. Alternatively or in addition to the fourteenth aspect a force generated by the at least one actuation element for changing the position of the moveable bus bar arrangement is transmitted by a worm gear. In this manner, it is ensured that the switching device only consumes energy when the position of the switching device is changed, while in an unpowered state of the electric motor, a position of the switching device is not changed. In this manner, the switching device allows to provide bi-stable states, and a state of the switching device is not changed when a sudden loss of power to the at least one actuation element occurs, for example resulting from a single point fault, another damage event or a communication error, but the contactor device stays in its prior state. Furthermore, the worm gear ensures a locking of the moveable bus bar arrangement in the first switching position or in the second switching position. Further, by its gear transmission ratio the worm gear contributes in providing the efficient force transmission from the at least one actuation element to the at least one driven member.

According to a thirteenth aspect, there is also provided an energy storage system comprising at least a first battery and a second battery and the switching device according to any of the preceding aspects, wherein the first battery and the second battery are electrically connected to the switching device in such a manner, that the first battery and the second battery are switchable by the switching device between a series state, in which the first battery and the second battery are electrically connected by the switching device in series, and a parallel state, in which the first battery and the second battery are electrically connected by the switching device in parallel.

Throughout this document, the term "terminal" is meant to describe a point at which a conductor from an electric device, an electric circuit or an electric component ends, and where a point is provided for electrically connecting an external electric device, an external electric circuit or an external electric component to this conductor. Furthermore, the terms "electrically connected" and "conductively coupled" describe the establishing of an electrical connection between at least two electric devices, electric components or electric conductors, which allows the flow of electric current. Hereby the electrical connection should not be restricted to a direct coupling of the terminals of the at least two electric devices, electric components or electric conductors, but other electric devices, electric components or electrical conductors may be coupled in between.

The accompanying drawings are incorporated into the specification and form a part of the specification to illustrate several examples of the present disclosure. These drawings, together with the description serve to explain the principles of the disclosure. The drawings are merely for the purpose of illustrating the preferred and alternative examples of how the disclosure can be made and used, and are not to be construed as limiting the disclosure to only the illustrated and described examples. Furthermore, several aspects of the examples may form-individually or in different combinations-solutions according to the present disclosure. The following described examples thus can be considered either alone or in an arbitrary combination thereof. Further features and advantages will become apparent from the following more particular description of the various examples of the disclosure, as illustrated in the accompanying drawings, in which like references refer to like elements, and wherein:.

The present disclosure will now be further explained referring to the Figures, and firstly referring to <FIG> shows a schematic circuit diagram of an exemplary high voltage energy storage system <NUM> that can benefit from the ideas of the present disclosure. The energy storage system <NUM> comprises two HV batteries <NUM>(<NUM>) and <NUM>(<NUM>), which, for example, form the driving battery of a battery driven vehicle, and a switching device <NUM>. Here and in the following, it will be assumed that each of the batteries <NUM>(<NUM>) and <NUM>(<NUM>) has an output voltage of 400V, but also other output voltages are conceivable. Each of the batteries <NUM>(<NUM>) and <NUM>(<NUM>) is usually formed of several battery modules or battery packs, which are again formed of a plurality of battery cells being connected in series and/or in parallel. In general, a number of HV batteries <NUM> provided in the energy storage system <NUM> is not restricted to two, but also more batteries may be used.

The switching device <NUM> comprises input terminals <NUM> and <NUM>. The input terminal <NUM> is configured to be electrically connected to a terminal <NUM> on the high potential side (+) of battery <NUM>(<NUM>). The input terminal <NUM> is configured to be electrically connected to a terminal <NUM> on the low potential side (-) of battery <NUM>(<NUM>). Further, the switching device <NUM> comprises output terminals <NUM> and <NUM>, which are configured to be electrically connected to a high voltage bus <NUM>, which, for example, is electrically connected to the drive train of a battery driven vehicle or to a charger (or charging station) for charging the high voltage batteries <NUM>(<NUM>) and <NUM>(<NUM>). The output terminal <NUM> is electrically connected to the high potential side (+) of the HV bus. Since the high potential side (+) of the HV bus is electrically connected by a node <NUM> to a terminal <NUM> on the high potential side (+) of battery <NUM>(<NUM>), the output terminal <NUM> is also electrically connected to the terminal <NUM> on the high potential side (+) of battery <NUM>(<NUM>). The output terminal <NUM> is electrically connected to the low potential side (-) of the HV bus. Since the low potential side (-) of the HV bus is electrically connected by a node <NUM> to a terminal <NUM> on the low potential side (-) of the battery <NUM>(<NUM>), the output terminal <NUM> is also electrically connected to the terminal <NUM> on the low potential side (-) of the battery <NUM>(<NUM>).

The switching device <NUM> is configured to switch the first battery <NUM>(<NUM>) and the second battery <NUM>(<NUM>) between a series connection state, in which the first battery <NUM>(<NUM>) and the second battery <NUM>(<NUM>) are electrically connected by the switching device <NUM> in series, and a parallel connection state, in which the first battery <NUM>(<NUM>) and the second battery <NUM>(<NUM>) are electrically connected by the switching device <NUM> in parallel. Accordingly, in the series connection state a voltage difference between the high potential side (+) and the low potential side (-) of the HV bus <NUM> is substantially equal to the sum of the voltages provided by the first battery <NUM>(<NUM>) and the second battery <NUM>(<NUM>) (e.g. 400V + 400V = 800V). On the other hand, in the parallel connection state a voltage difference between the high potential side (+) and the low potential side (-) of the HV bus <NUM> is substantially equal to the individual voltages provided by the first battery <NUM>(<NUM>) and the second battery <NUM>(<NUM>) (e.g. 400V). Accordingly, the switching device <NUM> allows to change the voltage applied to the HV bus <NUM> to be changed between a first lower voltage level, which may be equal to a charging voltage supplied to the batteries <NUM>(<NUM>) and <NUM>(<NUM>), and a second higher voltage level, which may be equal to a driving voltage for driving a battery driven vehicle.

<FIG> shows a schematic perspective view of an exemplary switching device <NUM>. The switching device <NUM> comprises a housing <NUM>, from which the input terminals <NUM> and <NUM> and the output terminals <NUM> and <NUM> protrude. Exemplarily, the housing comprises two parts, a housing base portion <NUM> and a housing cover <NUM>. In an exemplary configuration, the housing <NUM> may be a sealed housing, which would allow to provide a vacuum or an electronegative gas in the space encompassed by the housing <NUM>, to prevent the creation of sparks or arcing when switching the switching device <NUM>. The input terminals <NUM> and <NUM> and the output terminals <NUM> and <NUM> are formed, in the illustrated example, as cut-outs, which can be screwed to a respective external electric component, such as a terminal clamp of one of the batteries <NUM>(<NUM>) or <NUM>(<NUM>) or a bus bar, which is electrically connected to the switching device <NUM>. Alternatively, the input terminals <NUM> and <NUM> and the output terminals <NUM> and <NUM> may for example be formed as welding or soldering joints, which allow to weld or solder the switching device to the external electric components.

In the illustrated example, the housing <NUM> accommodates an electric motor <NUM> as an actuation element, which generates the transmission force for switching between the states of the switching device <NUM>. For connecting the electric motor <NUM> to a controller of the switching device <NUM> the electric motor <NUM> is connectable with motor connection pins <NUM>, which protrude from the housing <NUM> of the switching device. In alternative configurations, the electric motor <NUM> may be replaced by another actuation element known in the field of high voltage switching devices, for example by an electromagnetic actuator.

<FIG> show schematic perspective views of a part of the internal components of the switching device <NUM>. As illustrated, the housing <NUM> of the switching device accommodates a fixed contact arrangement and a moveable bus bar arrangement. The fixed bus bar arrangement includes, in the illustrated configuration, a first input bus bar <NUM> and a second input bus bar <NUM> as a pair of input bus bars, and a first output bus bar <NUM> and a second output bus bar <NUM> as a pair of output bus bars. The input bus bars <NUM> and <NUM> are electrically connected to respectively one of the input terminals <NUM> and <NUM>, in the shown example by integrally forming the input bus bars <NUM> and <NUM> with the respective input terminal. The output bus bars <NUM> and <NUM> are electrically connected to respectively one of the output terminals <NUM> and <NUM>, in the shown example by integrally forming the output bus bars <NUM> and <NUM> with the respective output terminal. The moveable bus bar arrangement, which is moveable in order to change the state of the switching device <NUM>, includes in the illustrated configuration a first connection bus bar <NUM> and a second connection bus bar <NUM> (see <FIG>). As will be explained later, the first connection bus bar <NUM> and the second connection bus bar <NUM> are configured to electrically connect respective bus bars of the fixed bus bar arrangement depending on the intended connection state of the switching device <NUM>.

It should be noted here that depending on application scenarios, the number of fixed bus bars and the number of moveable connection bus bars may vary from the numbers shown in the illustrated example, for example if the switching device <NUM> is configured to be electrically connected to more than two batteries (or battery strings) <NUM>.

In the illustrated example, when changing the position of the moveable bus bar arrangement, a force generated by the electric motor <NUM> is transmitted by a transmission unit <NUM> to the moveable bus bar arrangement. The transmission unit <NUM> comprises a shaft <NUM> having a fixedly mounted drive gear <NUM>. The drive gear <NUM> is in mesh with a worm <NUM>, so as to form a worm gear, which is driven by the electric motor <NUM>. The provision of the worm gear is not essential for the switching device <NUM>, but has the advantage that the torque generated by the electric motor <NUM> can be transmitted with an optimized transmission ratio to the shaft <NUM> compared to a direct mechanical coupling between the electric motor <NUM> and the shaft <NUM> without having a gear transmission in between. Further, the provision of the worm gear can prevent reversible force transmission through the worm gear, in order to prevent that rotation is transmitted back from the shaft <NUM> to the electric motor <NUM> when the electric motor <NUM> is not powered. Accordingly, by implementing the force transmission through the worm gear, the switching device <NUM> has a self-locking function, where it is only necessary to power the electric motor <NUM>, when changing the switching position of the switching device <NUM>.

For selectively translating the force generated by the electric motor <NUM> in a linear movement of the moveable bus bar arrangement or in a rotational movement of the moveable bus bar arrangement, the transmission unit <NUM> comprises a driven member <NUM> and an output member <NUM>, which carries the moveable bus bar arrangement. Thereby, the specific mechanical interplay between the driven member <NUM> and the output member <NUM>, which will be described in the following, enables the advantageous selective driving of a linear movement or of a rotational movement of the moveable bus bar arrangement of the switching device <NUM>.

The driven member <NUM> is fixedly mounted to the shaft <NUM>, for example by integrally forming the driven member <NUM> on the shaft <NUM>, so that the driven member is mechanically coupled to the drive gear <NUM> by the shaft <NUM>. Accordingly, the shaft <NUM> transmits a torque from the drive gear <NUM> to the driven member <NUM> when the electric motor <NUM> is powered to change the position of the switching device <NUM>. In the illustrated example, the driven member <NUM> is formed as a circular disc-shaped member with protruding arms <NUM>, whose function will be described later. Alternatively, it is also possible that the driven member <NUM> has a different outer shape or that more than one driven member is mounted to the shaft <NUM> and interacting with the output member <NUM> (or more than one output member).

The output member <NUM> is rotatable mounted to the shaft <NUM>, adjacent to the driven member <NUM>. Accordingly, the shaft defines an axis of rotation for the driven member <NUM> and for the output member <NUM>. In the illustrated example, the output member <NUM> is formed as a circular disc-shaped member. Alternatively, it is also possible that the output member <NUM> has a different outer shape or that more than one output member is coupled to the shaft <NUM> and interacting with the driven member <NUM> (or more than one driven member). The output member <NUM> is axially secured to the shaft <NUM> by a return spring <NUM>, which is preferably screwed to the shaft <NUM> and allows the output member <NUM> to perform a linear motion in a direction parallel to the extension direction of the shaft <NUM> (also signified as an axial direction) as will be explained later.

As shown in the example of <FIG>, the output member <NUM> comprises two mating half shells, one bottom half shell <NUM>, which carries the moveable bus bar arrangement and a top half shell <NUM>, which is imposed on the bottom half shell <NUM> to form the housing of the output member <NUM>. Alternatively, it is also possible to form the housing of the output member <NUM> from a single piece and to mount the connection bus bars to the output member <NUM> for example in a molding process. For illustration purposes, the top half shell <NUM> of the output member <NUM> is only indicated in <FIG> by dash-dotted lines. Accordingly, it becomes visible that the first connection bus bar <NUM> and the second connection bus bar <NUM> are provided in bus bar accommodation portions <NUM> of the output member <NUM>. Further, preloaded spring elements <NUM> are arranged in the inside of the output member <NUM> for resiliently supporting the connection bus bars <NUM> and <NUM> within the output member <NUM>. This allows for better controlling the contact forces between the connection bus bars <NUM> and <NUM> and the fixed bus bars of the switching device <NUM> when the output member <NUM> applies a force on the moveable bus bar arrangement to press the moveable bus bar arrangement onto the fixed bus bar arrangement. Further, the preloaded spring elements <NUM> contribute in absorbing small dislocations or imbalances between the connection bus bars <NUM> and <NUM> of the moveable bus bar arrangement.

<FIG> schematically show the switching device <NUM> in a parallel connection state. Hereby, <FIG> shows a schematic top view of the switching device <NUM> without the housing cover <NUM> to illustrate the position of individual components of the transmission unit <NUM> in the parallel connection state. <FIG> shows a schematic bottom view of the fixed contact arrangement and of the moveable contact arrangement to illustrate the positions of the moveable bus bar arrangement in the parallel connection state. As illustrated, in the parallel connection state the moveable bus bar arrangement is in a first switching position, where the first input bus bar <NUM> is electrically connected by the first connection bus bar <NUM> to the first output bus bar <NUM>. In addition, in the first switching position, the second input bus bar <NUM> is electrically connected by the second connection bus bar <NUM> to the second output bus bar <NUM>. Accordingly, in the parallel connection state, the switching device <NUM> electrically connects two batteries, which are connected to the input terminals <NUM> and <NUM>, in parallel (e.g. in the HV energy storage system <NUM> of <FIG>).

<FIG> schematically show the switching device <NUM> in a series connection state Hereby, <FIG> shows a schematic top view of the switching device <NUM> without the housing cover <NUM> to illustrate the position of individual components of the transmission unit <NUM> in the series connection state. <FIG> shows a schematic bottom view of the fixed contact arrangement and of the moveable contact arrangement of the switching device <NUM> in the series connection state to illustrate the positions of the connection bus bars <NUM> and <NUM> in the series connection state. As illustrated, in the series connection state the moveable bus bar arrangement is in a second switching position, where the first input bus bar <NUM> and the second input bus bar <NUM> are electrically connected with each other by the first connection bus bar <NUM>. Accordingly, in the series connection state, the switching device <NUM> electrically connects two batteries, which are connected to the input terminals <NUM> and <NUM>, in series.

While in the series connection state, the first connection bus bar <NUM> is in electric contact with both input bus bars <NUM> and <NUM>, the second connection bus bar <NUM> is in electric contact with at most one of the remaining fixed bus bars. In particular, in the shown exemplary configuration the second connection bus bar <NUM> is in electric contact with the second output bus bar <NUM>. The free contact point <NUM> of the second connection bus bar <NUM> is electrically isolated from the remaining fixed bus bars. In particular, in the shown exemplary configuration the second connection bus bar <NUM> is electrically isolated from the input bus bars <NUM> and <NUM> and from the first output bus bar <NUM> by a distance, which is large enough to prevent any arcing or other short circuit. Here, it should be mentioned that the necessary spacing between the free contact point <NUM> of the second connection bus bar <NUM> and the remaining fixed bus bars is especially easy to achieve due to the mounting of the connection bus bars <NUM> and <NUM> on the pivoted output member. Additional isolating elements, which ensure the isolation between the free contact point <NUM> of the second connection bus bar <NUM> and the remaining fixed bus bars are not necessary, but may be provided in addition to enhance the safety and reliability of the switching device <NUM>.

For moving the moveable bus bar arrangement between the first switching position and the second switching position, the moveable bus bar arrangement is rotated in a plane, which is parallel to the extension directions of the connection bus bars <NUM> and <NUM> of the moveable bus bar arrangement, here with the shaft <NUM> as an axis of rotation. This means that the rotation of the moveable bus bar arrangement does not change the alignment of the connection bus bars <NUM> and <NUM> with respect to each other, but only the orientation of the moveable bus bar arrangement as a whole. Accordingly, the rotation of the moveable bus bar arrangement does not result, for example, in a tilting or twisting of the connection bus bars <NUM> and <NUM> compared to each other.

For rotating the moveable bus bar arrangement, the output member <NUM>, on which the first connection bus bar <NUM> and the second connection bus bar <NUM> are mounted, is coupled to the driven member <NUM> in a rotationally driving manner in a first angular range. Accordingly, the output member <NUM> is rotated about its axis of rotation, which corresponds to the axis of rotation of the driven member <NUM> and is defined by the shaft <NUM>.

As illustrated in <FIG>, the freedom of rotational movement of the output member <NUM> is restricted to the first angular range by protruding lugs <NUM>, which protrude from the circular base of the output member <NUM>, which interact with a wall structure <NUM> of the switching device, which functions as an output member blocking element. The wall structure <NUM> extends upwards from the base of the housing <NUM>, in particular from the housing base portion <NUM>, and encompasses the output member <NUM> in a circumferential direction. Hereby, an inner radius of the wall structure <NUM> is designed to be smaller than a radius of the output member <NUM> at the position of the protruding lugs <NUM>. When the protruding lugs <NUM> reach the boarders of the first angular range, the protruding lugs <NUM> engage with the wall structure <NUM> by abutting against the wall structure <NUM> to stop the rotational movement of the output member <NUM> in the clockwise or counterclockwise. <FIG> shows a schematic indication of the boarders of the first angular range by the dashed lines <NUM> and <NUM>, where the protruding lugs <NUM> engage with the wall structure <NUM> (for illustration purposes only indicated for one of the lugs <NUM>). The dashed lines <NUM> and <NUM> encompass the first angular range as a movement region I of the output member <NUM>, or more specifically as a movement region where the lugs <NUM> allow for a rotational movement of the output member <NUM>. The possible direction of movement of the output member <NUM> in the first angular range is schematically indicated by the arrow <NUM>. To allow for the rotation of the output member <NUM>, and especially for the protruding lugs <NUM> within the first angular range, a height of an intermediate part <NUM> of the wall structure <NUM> is lowered in the first angular range compared to a height of the remaining part of the wall structure <NUM>.

In the shown example, the wall structure <NUM> is provided as a single part, being integrally formed with the base portion of the housing <NUM>. However, this is merely an example, and the wall structure <NUM> could be also formed of several separated parts, and/or arranged within the switching device <NUM> separately from the housing <NUM>. Further, in the shown example, two lugs <NUM> are provided for the output member <NUM>. However, depending on application scenarios also another number of lugs <NUM> is possible, and the design of the wall structure <NUM> (or of another output member blocking element) may be adapted accordingly.

As outlined above, for being rotated the output member <NUM> is coupled in a rotationally driving manner to the driven member <NUM>, at least when the driven member <NUM> drives the rotational movement of the output member <NUM> between the boarders of the first angular range. This allows the driven member <NUM> to transfers the torque generated by the electric motor <NUM> to the output member <NUM> and to rotate the output member <NUM> in the first angular range. For coupling the output member <NUM> to the driven member <NUM> in the first angular range, the driven member can comprise on its bottom side a plurality of notches <NUM> (see <FIG>), but at least one notch <NUM>, to form a notch profile. The output member <NUM> can comprise on its top side, i.e. on the side facing away from the connection bus bars <NUM> and <NUM>, a plurality of hubs <NUM> (see <FIG>), but at least one hub <NUM>, to form an interlocking hub profile, which can mate with the notch profile of the driven member. For achieving an optimal torque transmission, the number of hubs <NUM> preferably corresponds to the number of notches <NUM>, and the hubs <NUM> preferably mate with the notches <NUM> in a form-fitting manner, when the driven member <NUM>. However, also other configurations are possible, depending on application scenarios.

While the rotational movement of the moveable bus bar arrangement between the first switching position and the second switching position has many advantages like allowing to reduce the overall weight of the switching device <NUM>, a pure rotational movement of the moveable bus bar arrangement enhances the friction on contact elements, which are arranged at the contact points of the bus bar arrangement, so that the contact elements could be easily damaged. The contact elements, which are for example made of silver or any silver alloy to form silver buttons, or of other suitable electrically conducting materials are usually sensitive structures, are however advantageous, since they allow for reducing a contact resistance in the series connection state and in the parallel connection state. Hence, damaging of the contact elements could result in a serious degradation of the performance of the switching device <NUM>.

Accordingly, for reducing the friction on the contact elements, when opening the contacts between the moveable contact arrangement and the fixed contact arrangement, the moveable bus bar arrangement advantageously is separated from the fixed bus bars of the fixed bus bar arrangement by a linear movement, before the rotation of the moveable contact arrangement is performed. For example, when opening the contacts of the switching device <NUM>, the moveable bus bar arrangement is lifted up in a direction parallel to the axis of rotation of the output member <NUM> (or of the driven member <NUM>) before the rotation of the moveable contact arrangement is performed. Similar, when closing the contacts between the moveable contact arrangement and the fixed contact arrangement, the moveable bus bar arrangement advantageously is brought in contact with the fixed bus bars of the fixed bus bar arrangement by a linear movement, after the rotation of the moveable contact arrangement has been performed after the rotational movement of the moveable contact arrangement has been performed. For example, when opening the contacts of the switching device <NUM>, the moveable bus bar arrangement is lowered in a direction parallel to the axis of rotation of the output member <NUM> (or of the driven member <NUM>) after the rotation of the moveable contact arrangement has been performed.

In general, for linear moving the moveable bus bar arrangement, a second dedicated actuation element could be provided in the switching device <NUM>, wherein the second actuation element generates a force for linearly moving the moveable bus bar arrangement, for example by lifting and lowering the output element <NUM>. However, to simplify the configuration of the switching device <NUM>, the linear movement of the moveable bus bar arrangement is advantageously also driven by the electric motor <NUM> and the transmission unit <NUM> is designed in such a manner that, for linearly moving the moveable bus bar arrangement, the torque generated by the electric motor <NUM> is translated into a linear force.

For this purpose, the transmission unit <NUM> converts the torque applied to the driven member <NUM> into an axial force, which acts upon the output member <NUM> in a direction parallel to the extension direction of the shaft <NUM>, when the driven member <NUM> is rotated outside of the first angular range, to which the rotational movement of the output member <NUM> is restricted. By the applied axial force, the output member <NUM> is forced to move towards the fixed contact arrangement. In particular, when the driven member <NUM> is driven outside of the first angular range, the notches <NUM> of the driven member <NUM> disengage from the hubs <NUM> of the output member <NUM> and start sliding across the hubs <NUM>. In order to allow for a smooth uncoupling when the hubs <NUM> are disengaged from the notches <NUM>, in a preferable configuration the hubs <NUM> of the toothed hub profile are formed as beveled wedges and the notches <NUM> have a corresponding mating profile.

By the disengaging, the output member <NUM> is shifted by the hubs <NUM> in the direction parallel to the extension direction of the shaft <NUM> due to the interplay between the hubs <NUM> and the intermediate regions <NUM> of the driven member <NUM>, which are provided between each adjacent notches <NUM> and are extending at an elevated height compared to the notches <NUM>. The maximum shift of the output member <NUM> (and of the connection bus bars <NUM> and <NUM> carried by the output member <NUM>) in the axial direction is accordingly given by the maximum height of the hubs <NUM> and by the elevation of the intermediate regions <NUM> (compared to the notches <NUM>). In order to use the maximum shift for positioning the connection bus bars <NUM> and <NUM> on the fixed contact arrangement and to prevents an unwanted re-coupling of the driven member <NUM> with the output member <NUM> when the driven member <NUM> is driven outside the first angular range, the rotational movement of the driven member <NUM> is restricted to a second angular range.

For this purpose, as shown in <FIG>, the freedom of rotational movement of the driven member <NUM> is restricted to the second angular range, which is the first angular range by protruding lugs <NUM>, which protrude from the arms <NUM> of the driven member <NUM>. The protruding lugs <NUM> interact with a wall structure <NUM>, which functions as a driven member blocking element. The wall structure <NUM> extends upwards from the base of the housing base portion <NUM> at least until a height, where it can interact with the protruding lugs <NUM>. Hereby, an inner radius of the wall structure <NUM> is designed to be smaller than a radius of the driven member <NUM> at the position of the protruding lugs <NUM>. When the protruding lugs <NUM> reach the boarders of the second angular range, the protruding lugs <NUM> engage with the wall structure <NUM> by abutting against the wall structure <NUM> to stop the rotational movement of the driven member <NUM> in the clockwise or counterclockwise. <FIG> shows a schematic indication of the boarders of the second angular range by the continuous lines <NUM> and <NUM>, where the protruding lugs <NUM> engage with the wall structure <NUM> (for illustration purposes only indicated for one of the lugs <NUM>) in addition to the indication of the boarders of the first angular range by the dashed lines <NUM> and <NUM>. In the shown example, one lug <NUM> is provided on each arm <NUM> of the driven member <NUM>. However, depending on application scenarios also another number of lugs <NUM> per arm <NUM> or another number of arms <NUM> is possible, and the design of the wall structure <NUM> may be adapted accordingly.

As illustrated in <FIG>, the freedom of radial movement of the driven member <NUM> or more specifically the radial movement of the lugs <NUM> of the driven member <NUM> is less restricted than the freedom of radial movement of the output member <NUM> or more specifically the radial movement of the lugs <NUM> of the output member <NUM>. In particular, the second angular range encompasses the movement region I, where the driven member <NUM> is rotationally coupled to the output member <NUM>, and in addition comprises the movement region II (between solid line <NUM> and dashed line <NUM>) and movement region III (between solid line <NUM> and dashed line <NUM>), where the driven member <NUM> applies an axial force on the output member <NUM> to change the elevation of the output member. The possible direction of movement of the driven member <NUM> in the first angular range is schematically indicated by the arrow <NUM>.

<FIG> show schematic perspective views of the switching device <NUM> at various points of the switching process when switching the switching device <NUM> from the series connection state (<FIG>) to the parallel connection state (<FIG>). To illustrate the functioning of the internal components of the switching device <NUM>, especially of the transmission unit <NUM>, during the switching process, the housing <NUM> of the switching device <NUM> is only partly shown in <FIG>.

In the series connection state shown in <FIG>, the driven member <NUM> experiences its maximum displacement in the clockwise direction (as seen from top of the switching device <NUM>), so that the lugs <NUM> of the driven member <NUM> abut against the wall structures <NUM> in the clockwise direction. Also the output member <NUM> experiences its maximum displacement in the clockwise direction, so that the lugs <NUM> of the output member <NUM> abut against the wall structure <NUM> in the clockwise direction. Thereby, the lugs <NUM> are guided by a first guiding groove <NUM>. The first guiding groove <NUM> restricts the movement of the output member <NUM> to an axial movement by engagement with the lugs <NUM> when the moveable bus bar arrangement is opening or closing the contacts with the fixed bus bar arrangement in the second switching position. Since the first guiding groove <NUM> is defined on one side of a part of the wall structure <NUM> extending to its full height and on the other by the lowered intermediate part <NUM> of the wall structure <NUM>, the side walls of the first guiding groove <NUM> have asymmetric heights.

In the series connection state, the hubs <NUM> of the output member <NUM> are disengaged from the notches <NUM> of the driven member and by the interplay between the hubs <NUM> and the intermediate regions <NUM> of the driven member <NUM>, the output member <NUM> is maximally displaced in the axial direction (indicated by arrow <NUM>) away from the driven member <NUM>. Accordingly, the output member <NUM> presses the first connection bus bar <NUM> and the second connection bus bar <NUM> on the fixed bus bar arrangement, so that the first input bus bar <NUM> and the second input bus bar <NUM> are electrically connected with each other by the first connection bus bar <NUM> (see <FIG>).

<FIG> shows the switching device in a first position after the driven member <NUM> is rotated by the motor <NUM> in the counterclockwise direction (as seen from top of the switching device <NUM>) away from the series connection state. In this position, which corresponds to a position in movement region II of <FIG>, the displacement of the driven member <NUM> is lowered, but the driven member <NUM> is still driven outside the first angular range, so that the output member <NUM> still experiences its maximum displacement in the clockwise direction. Accordingly, the output member <NUM> is not rotated compared to the series connection state, so that the moveable bus bar arrangement still has the same orientation as in the second switching position, but is already elevated above the fixed bus bar arrangement. However, the hubs <NUM> of the output member <NUM> are already partly engaging with the notches <NUM> of the driven member <NUM>, due to the return force applied by the return spring <NUM> on the output member <NUM> in the axial direction, opposite to the direction of arrow. Accordingly, the connection bus bars <NUM> and <NUM> of the moveable bus bar arrangement are lifted up in a linear movement compared to the series connection state of <FIG>. In this position, the movement of the output member <NUM> is still restricted to a linear movement in the axial direction by the intermediate parts <NUM> of the wall structure <NUM>, which engage with the lugs <NUM> of the output member <NUM> until the hub profile of the output member <NUM> is fully engaged with the notch profile of the driven member <NUM>.

<FIG> shows the switching device <NUM> in a second position after the driven member <NUM> is rotated by the motor <NUM> in the counterclockwise direction away from the series connection state.

In this position, which corresponds to a position in movement region I of <FIG>, the output member <NUM> is coupled the driven member in a form-fitting and rotational driving manner by a form-fitting engagement of the hub profile with the notch profile (see also the cross-section of <FIG>). Accordingly, in this position the moveable bus bar arrangement is fully elevated and in a position, where it can be rotated. The torque applied to the driven member <NUM> is transferred to the output member <NUM> and drives the output member <NUM> in the counterclockwise direction, so that the moveable bus bar arrangement experiences a rotation in the counterclockwise direction towards the first switching position. Since the output member <NUM> is sufficiently lifted up, the lugs <NUM> of the output member <NUM> are not inhibited by the intermediate parts <NUM> of the wall structure <NUM>.

<FIG> shows the switching device <NUM> in a third position after the driven member <NUM> is rotated by the motor <NUM> in the counterclockwise direction away from the series connection state. In this position, which corresponds to the boarder of movement region I indicated by dashed line <NUM> in <FIG>, the output member reaches its maximum displacement in the counterclockwise direction. In this position, the lugs <NUM> of the output member abut against the wall structure <NUM> above second guiding grooves <NUM>, which restrict the movement of the output member <NUM> to an axial movement by engaging of the lugs <NUM>. The moveable bus bar arrangement already has the same orientation as in the first switching position (see <FIG>), but is still elevated above the fixed bus bar arrangement. Due to the restriction of the rotational movement of the output member <NUM>, the notches <NUM> start to disengage from the hubs <NUM> when the driven member <NUM> is rotated from the third position further in the counterclockwise direction, i.e. into the movement region III of <FIG>. Accordingly, when the driven member <NUM> is rotated from the third position further in the counterclockwise direction the driven member acts an rotational force on the output member <NUM> in the axial direction by the interplay between the between the hubs <NUM> of the output member <NUM> and the intermediate regions <NUM> of the driven member <NUM>, so that the output member <NUM> is moved in the axial direction along the direction <NUM>.

<FIG> shows the switching device <NUM> in the series connection state, where the driven member <NUM> experiences its maximum displacement in the counterclockwise direction, so that the lugs <NUM> of the driven member <NUM> abut against the wall structure <NUM> in the counterclockwise direction. Also the output member <NUM> experiences its maximum displacement in the counterclockwise direction, so that the lugs <NUM> of the output member <NUM> abut against the wall structure <NUM> in the counterclockwise direction. Thereby, the lugs <NUM> are guided by a second guiding groove <NUM>, which restrict the movement of the output member <NUM> to the axial movement when the moveable bus bar arrangement is opening or closing the contacts with the fixed bus bar arrangement in the first switching position. Since the second guiding groove <NUM> is defined on one side of a part of the wall structure <NUM> extending to its full height and on the other by the lowered intermediate part <NUM> of the wall structure <NUM>, the side walls of the second guiding groove <NUM> have asymmetric heights.

In the series connection state, the hubs <NUM> of the output member <NUM> are disengaged from the notches <NUM> of the driven member and by the interplay between the hubs <NUM> and the intermediate regions <NUM> of the driven member <NUM>, the output member <NUM> is maximally displaced in the axial direction (indicated by arrow <NUM>) away from the driven member <NUM>. Accordingly, in this position the output member <NUM> presses the first connection bus bar <NUM> and the second connection bus bar <NUM> on the fixed bus bar arrangement, so that the first input bus bar <NUM> is electrically connected by the first connection bus bar <NUM> to the first output bus bar <NUM> and the second input bus bar <NUM> is electrically connected by the second connection bus bar <NUM> to the second output bus bar <NUM> (see <FIG>).

The switching process between the series connection state (<FIG>) and the parallel connection state (<FIG>) of the switching device <NUM> is reversible, so that the switching process from the parallel connection state to the series connection state proceeds analogously to the above description when the driven member <NUM> is driven by the electric motor <NUM> in the clockwise direction.

Claim 1:
A switching device (<NUM>) comprising:
a fixed bus bar arrangement, which comprises at least a pair of fixed input bus bars (<NUM>, <NUM>) and a pair of fixed output bus bars (<NUM>, <NUM>);
a moveable bus bar arrangement, which comprises at least a first connection bus bar (<NUM>) and a second connection bus bar (<NUM>); and
at least one actuation element (<NUM>), which is configured to change a position of the moveable bus bar arrangement at least to and from a first switching position and to and from a second switching position;
wherein in the first switching position, each of the fixed input bus bars (<NUM>, <NUM>) is electrically connected to respectively one of the fixed output bus bars (<NUM>, <NUM>), and in the second switching position, the pair of fixed input bus bars (<NUM>, <NUM>) is electrically connected to each other, and
characterized in that
the switching device (<NUM>) further comprises a transmission unit (<NUM>) having at least one driven member (<NUM>) and at least one output member (<NUM>), which are coupled to one another in a rotationally driving manner in a first angular range, wherein the moveable bus bar arrangement is supported on the at least one output member (<NUM>), and
wherein the at least one driven member (<NUM>) applies an axial force upon the at least one output member (<NUM>), when the at least one driven member (<NUM>) is driven outside of the first angular range, such that the at least one output member (<NUM>) moves the moveable bus bar arrangement along a direction at least substantially parallel to the axis of rotation of the driven member (<NUM>), and
wherein the at least one actuation element (<NUM>) is configured to rotate the driven member (<NUM>) for changing the position of the moveable bus bar arrangement to and from the first switching position and to and from the second switching position.