Patent Application
20190232809
The invention relates to the field of charging of electric vehicles. More specifically, it relates to the field of automatic devices for electromechanical coupling allowing charging of electric vehicles from a charging station. The invention applies in particular to automatic devices allowing charging of electric vehicles, more particularly public transport vehicles, such as buses and tramcars. More specifically, the invention relates to a safety system for an electromechanical coupling assembly, capable of equipping a charging station and an electric vehicle. The invention also relates to the corresponding electromechanical coupling assembly and charging station, as well as a coupling (or approach) method for an electric vehicle vis-à-vis a charging station.
Electric vehicles comprising an electric drive train traditionally carry on board at least one energy storage device, for example in electrochemical form or capacitive form. Charging the energy storage device with energy can be carried out via an energy converter carried on board the vehicle. This energy converter can in particular be arranged in order to recover the kinetic energy of the vehicle during braking phases. Charging the storage device with energy can also be carried out from a charging station, for example placed at a stopping station provided for the boarding and alighting of passengers. Most of the time, the transfer of electrical energy between the charging station and the electric vehicle is carried out by an electromechanical coupling assembly divided between the charging station and the electric vehicle. The electromechanical coupling assembly comprises a first connection part, electrically connected to an electrical supply source of the charging station, and a second electrical connection part, electrically connected to the energy storage device of the vehicle. These connection parts are capable of mechanical coupling so as to make an electrical contact between the charging station and the energy storage device, allowing an electric charging current to flow.
In order to facilitate charging and in particular to avoid all human intervention, it is possible to automate the electromechanical coupling operation and, more generally, all of the operations necessary for charging the electric vehicle. The electromechanical coupling assembly thus generally comprises an actuator, arranged in order to move one of the connection parts relative to the other connection part, and a control unit, arranged in order to drive the actuator in an automated manner, for example following a charging instruction. By way of example, EP 1 938 438 describes an electromechanical coupling assembly comprising an extensible arm arranged on the roof of a vehicle and intended to connect in a socket with which the charging station is equipped.
A drawback of the electromechanical coupling assemblies of the state of the art is that, during an approach phase of the mobile element (male or female) towards the fixed element (male or female, respectively) in order to establish the coupling thereof, there is a risk that a foreign body may be introduced between the male element and the female element. The foreign body can in particular prevent the coupling between the male and female elements, or the connection between these elements. The foreign body can also be a limb or a part of a limb of a human being or an animal. In addition to the risk of incorrect coupling is thus added a risk of injury. In order to limit these risks, the coupling of the male part and the female part must be carried out with particular constraints, regulated by standards in certain countries.
In the context of the charging of an electric vehicle, the risks of injury and of damage can be limited by providing for an installation of the electromechanical coupling assembly at a height greater than a threshold height. For a public transport vehicle of the bus or tram type, this threshold height is for example set at 2.70 m, so as to prevent the introduction of a user's hand into the female element. However, such an installation at height requires a minimum height for the vehicle, which can be incompatible with certain routes that the vehicle must travel, for example, routes comprising height-limited access (tunnels, bridges). When the electromechanical coupling assembly cannot be installed above a threshold height, it is possible to limit the risk of injury by setting a maximum strength for the force applied during the movement of the mobile element towards the fixed element. This maximum strength is for example equal to 70 N, in order to prevent any injury to a user, even in the event of pinching. However, a correct coupling of the male element with the female element generally requires a relatively significant force, called insertion force, the strength of this force being capable for example of exceeding 800 N. In particular, such a force is recommended due to imperfect alignment of the male element with the female element, as the electric vehicle is only able to position itself approximately with respect to the charging station. Furthermore, the need to carry out effective coupling of the coupling unit is underlined by the fact that an electric current of a relatively significant amperage flows through it in order to charge the electric vehicle.
A solution for positioning the coupling assembly at a relatively low height, while allowing a strong insertion force would be to determine the position of the mobile element relative to the support thereof, for example the charging station, and to deduce therefrom the position thereof with respect to the vehicle. In particular, in the case where the mobile element is moved along an axis perpendicular to a longitudinal axis of the road; the position thereof relative to the fixed element can be determined from the distance of displacement thereof along this axis. The mobile element can then be moved firstly with a relatively limited force, and secondly with a greater force, in order to ensure correct coupling. A risk exists, however, from the fact that the positioning of the electric vehicle risks varying between different successive chargings. Thus, if the vehicle is too close to the charging station, the position from which the force is increased risks not being reached. Conversely, if the vehicle is positioned too far from the charging station, the position from which the force is increased is reached while the space between the male element and the female element is sufficient for a foreign body to be inserted therein.
US 2009/079388 describes a connection device comprising means for detecting the position of the female element and adjusting the movement of the male element so that it couples accurately with the female element. The connection device can be arranged in order to detect the presence of an obstacle and react either by retracting the male element or by avoiding the obstacle. This solution involves the use of an actuator and relatively complex detection means. In particular, the detection means must be able to distinguish the female element from an obstacle. When it is sought to avoid the obstacle, the actuator must then be able to carry out a complex movement, composed of several translational and/or rotational movements. The coupling assembly is thus relatively complex and costly to make.
A purpose of the invention is in particular to overcome the above-mentioned drawbacks entirely or in part by proposing a safety system for an electromechanical coupling assembly which makes it possible to correctly couple two complementary connection elements, i.e. applying a sufficient insertion force, while guaranteeing the safety of property and people during coupling. For this purpose, the invention proposes to equip one of the connection parts of the electromechanical coupling assembly with a detectable element and to equip the other connection part with a sensor configured in order to determine if the detectable element is situated or not situated in proximity. The detectable element and the sensor are arranged on the connection parts so that the detection only operates when the connection parts are sufficiently close to one another to prevent the insertion of a foreign body between these parts. The mobile connection part can then be moved with a relatively low-strength force in a first phase and with greater force in a second phase, in which the risk of introduction of a foreign body is limited or nonexistent.
More specifically, a subject of the invention is a safety system for an electromechanical coupling assembly capable of equipping a charging station and an electric vehicle. The electromechanical coupling assembly intended to be equipped with the safety system can comprise:
The predetermined proximity to the sensor is for example delimited by a sphere centred on the sensor and having a predetermined radius. The radius is for example equal to 50 mm. In practice, the surroundings of the sensor and the detection technology used generally define a more complex outline for this predetermined proximity.
In the retracted position, the sensor is sufficiently distant from the detectable element so as not to be detected. It then provides a signal having the non-detection value.
The proximity position corresponds to an intermediate position between the retracted position and the connection position. It is determined by the detection of the detectable element by the sensor. Thus, it always corresponds to one and the same relative position between the two connection parts, or optionally to one and the same set of relative positions between the connection parts. In the case where the coupling of the connection parts is carried out by a translational movement of one of the connection parts, the intermediate position is defined by a certain travel of the connection part. This travel is not defined in a fixed manner but depends on the relative position of the electric vehicle and the charging station.
Advantageously, the sensor and the detectable element are positioned on the connection parts so that, in the intermediate position, i.e. the position in which the sensor detects (or begins to detect) the detectable element, the connection parts are sufficiently close to each other to prevent the insertion of a foreign body between them.
Between the proximity position and the connection position, the movement of the first connection part can be carried out with a force the amplitude of which is greater than that of the force leading to the movement of this first connection part between the retracted position and the proximity position. In particular, the control unit can be arranged in order to control a movement of the first connection part from the proximity position to the connection position with a force the amplitude of which is greater than a minimum amplitude F2min. This minimum amplitude F2min is typically greater than the maximum amplitude F1max.
The minimum amplitude F2min is preferably determined so as to allow correct coupling of the connection parts. It can in particular depend on the intrinsic mechanical constraints of the connection elements, and manufacturing tolerances of these elements. It is for example greater than or equal to 350 N, for example of the order of 450 N.
According to a particular embodiment, the sensor is firmly fixed to the first connection part and the detectable element is firmly fixed to the second connection part. This embodiment is of particular benefit when the coupling of the connection parts is carried out by a movement of the first connection part. The sensor can then provide detection information to the actuator without any data link (wired or wireless) between the electric vehicle and the charging station.
The first connection part comprises for example a male element and the second connection part a female element. The female element is then arranged in order to be able to receive the male element during a coupling. Preferably, the detectable element and the sensor are arranged so that, in the proximity position, the male element is partially inserted into the female element. The concept of proximity between the connection parts then corresponds to a partial insertion of the male element into the female element.
According to a particular embodiment, the male element comprises a first tube and a second tube arranged end to end, optionally in a concentric manner, the first tube having a first diameter and the second tube having a second diameter, strictly less than the first diameter. The female element comprises a first bore and a second bore arranged end to end, optionally in a concentric manner, the first bore having a third diameter and the second bore having a fourth diameter, strictly less that the third diameter and the first diameter, the male element and the female element being arranged so that, in the connection position, the first tube is inserted into the first bore and the second tube is inserted into the second bore. The first and third diameters can be equal, give or take a small working clearance. Similarly, the second and fourth diameters can be equal, give or take a small working clearance. The detectable element and the sensor can then be arranged so that, in the proximity position, the second tube is inserted at least partially into the first bore.
Advantageously, the detectable element and the sensor are arranged so that, in the proximity position, the second tube is also inserted partially into the second bore. In other words, the second tube is inserted into the first bore and partially into the second bore.
In the context of the present invention, a partial insertion of a male element into a female element means that the male element has entered the female element without having reached a final position of travel, corresponding to the connection position.
The first and the second tube can have a globally cylindrical shape, for example with a circular cross-section. The tubes can also have other shapes. In this case, the diameters in question are the diameters of circles circumscribed to the cross-section of the tubes.
According to the latter particular embodiment, the sensor can be situated at a free end of the second tube and the detectable element situated at a junction between the first bore and the second bore.
According to another particular embodiment, the male element comprises a single tube having a first diameter and the female element comprises a single bore having a second diameter. The male element and the female element can then be arranged so that, in the proximity position, the tube is partially inserted into the bore. The first and second diameters can be equal, give or take a small working clearance.
According to a first variant embodiment, the operation of the sensor is based on purely magnetic properties. The detectable element comprises for example a magnet and the sensor a magnetic sensor. This variant embodiment has the advantage of not introducing an electromagnetic field capable of disturbing the electrical signals passing through the electric conductors situated in proximity to the safety system. In this case, the electromechanical coupling assembly can comprise an end-of-travel sensor operating by electrical contact, as shown below. The operation of this end-of-travel sensor is not influenced by the presence of the magnet.
According to a second variant embodiment, the operation of the sensor is based on radio-frequency identification technology, better known by the acronym “RFID”. The detectable element comprises for example a radio-frequency identification tag and the sensor a radio-frequency identification reader. The use of RFID technology makes it possible for the sensor to identify the connection part bearing the RFID tag. It can in particular be used in order to verify the matching ability of the connection parts or in order to change the charging of the electric vehicle, for example the voltage applied for the charging.
The detectable element is for example mounted in the electric vehicle and arranged in order to transmit a piece of identification information of the electric vehicle to the sensor when the detectable element is situated within the predetermined proximity to the sensor. This identification information can in particular be used in order to verify that the electric vehicle is adapted to a charging at the charging station or that it is authorized to charge at this charging station.
The maximum amplitude F1max is preferably determined so as to limit or even prevent any risk of injury to a person. It is more particularly less than or equal to 100 N, for example of the order of 70 N.
A subject of the invention is also an electromechanical coupling assembly capable of equipping a charging station and an electric vehicle. The electromechanical coupling assembly comprises:
According to a particular embodiment, the actuator is arranged in order to be able to move the first connection part relative to the second connection part by a translational movement, the male element and the female element being capable of coupling by means of this translational movement. The actuator comprises for example a hydraulic cylinder or a mechanism of the endless screw type.
The electromechanical coupling assembly can also comprise an end-of-travel sensor, arranged in order to detect a positioning of the first connection part in the connection position. In other words, the end-of-travel sensor can be arranged in order to detect the end of the coupling phase of the connection parts. This positioning information can in particular be used in order to initiate a transfer of electrical energy from the charging station to the electric vehicle.
A subject of the invention is also a charging station for charging an electric vehicle with electrical energy. The charging station comprises:
The different features described with reference to the safety system and the electromechanical coupling assembly apply to the charging station.
Finally, a subject of the invention is a method for electromechanical coupling of an electric vehicle with a charging station, the charging station comprising:
According to a particular embodiment, the coupling method comprises, during the step of moving the first connection part relative to the second connection part, a monitoring step, in which it is ascertained whether the first connection part is positioned or not positioned in the intermediate position using a sensor firmly fixed to one of the connection parts and a detectable element connected the other connection part, the detectable element capable of being detected by the sensor.
Other advantages and features of the invention will become apparent on reading the detailed description of implementations and embodiments which are in no way limitative, with respect to the attached drawings, in which:
The embodiments described below are in no way limitative; it is possible in particular to consider variants of the invention comprising only a selection of characteristics described, in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention with respect to the state of the prior art. This selection comprises at least one, preferably functional, characteristic without structural details, or with only a part of the structural details if this part alone is sufficient to confer a technical advantage or to differentiate the invention with respect to the state of the prior art.
The charging station 20 is for example placed near to a traffic lane 30, for example at a stopping point, or station, provided for the boarding and alighting of passengers. The charging station 20 comprises a body structure 21, a connection part 22, an actuator 23 and a control unit 24. It also comprises an electrical supply source (not shown). The supply source can comprise a pair of electrical terminals capable of being electrically connected to the connection part 22. It can also comprise a controlled switch and/or an energy converter such as a rectifier and, more generally, any electrotechnical system allowing the operation of charging and discharging an electrical energy storage device from a supply source. The actuator 23 is mounted on an upper end of the body structure 21, so as to limit access thereto by users of the electric vehicle. The connection part 22 comprises a male element intended to couple with the female element of the connection part 12. It is mounted on a mobile part of the actuator 23, so as to be able to adopt a position called retracted position, in which is it not coupled to the connection part 12, and a connection position, in which it is coupled to the connection part 12. In the retracted position, the connection part 22 must be sufficiently distant from the traffic lane 30 so as to not constitute a possible obstacle for the electric vehicle 10, when it travels on the traffic lane 30, and in particular when it is positioned in proximity to the charging station 20 in order to be charged. In
The electromechanical coupling assembly 40 also comprises a safety system 41 arranged in order to couple the connection parts 12 and 22 with a variable strength of force as a function of the relative proximity of these connection parts. The safety system 41 comprises a detectable element 411, a sensor 412 and a control unit 413. The sensor 412 is firmly fixed to the connection part 22. It is mounted at an end of the cylindrical tube 222, for example in a housing made in the cylindrical tube 222. The detectable element 411 is placed, for example, in an orifice 124 of the connection part 12, opening one the one hand onto an outer surface of the connection part 12 and on the other hand onto the junction of the bores 121 and 122. The detectable element 411 is firmly fixed to the connection part 12. It is for example inserted into the connection part 12 by placing it on the end of a screw capable of being screwed into the bore 124. The detectable element 411 and the sensor 412 are arranged with respect to each other so that the sensor 412 can detect the detectable element 411 when it reaches proximity to the junction between the bores 121 and 122. The area, called detection area, in which the detectable element 411 is capable of being detected by the sensor 412 is shown by a circle 414. This circle shows diagrammatically a spherical shape the centre of which is situated at the detectable element 411. The radius of the circle 414 is for example equal to 50 mm. Of course, the detection area is diagrammatic, the outline thereof in particular able to be influenced by the geometry and the material of the connection part 12, as well as by the detection technology used by the sensor 412. Moreover, the sensor 412 and the detectable element 411 must be arranged so that the detection area has a shape adapted to the dimensions of the connection parts 12 and 22.
The sensor 412 is fixed to the connection part 22 and, more particularly, at the free end of the cylindrical tube 222. It is for example inserted into a housing made in the cylindrical tubes 221 and 222. This housing (not shown) opens for example onto the end of the cylindrical tube 221 opposite the junction with the cylindrical tube 222. The sensor 412 is arranged in order to provide a detection signal to the control unit 413 as a function of the detection of the detectable element 411. The detection signal has a value called detection value, when the sensor 412 detects the detectable element 411, and a value called non-detection value otherwise. The detection signal can be transmitted by wired transmission means or wireless transmission means. The sensor 412 comprises for example a magnetic sensor. The detectable element 411 can then be a simple magnet. The sensor 412 can alternatively comprise a radio-frequency identification (RFID) reader. The detectable element 411 is then an RFID tag, arranged in order to exchange identification data. The RFID tag can in particular store and communicate data relative to the electric vehicle equipped therewith. These data are not necessarily processed for their content but may be used only to indicate the proximity of the RFID tag to the RFID reader.
The positioning of the detectable element 411 on the connection part 12 and of the sensor 412 on the connection part 22 makes it possible to identify a position called proximity position of the connection part 22 with respect to the connection part 12, as shown in
The control unit 413 is arranged in order to influence the behaviour of the actuator 23 as a function of the detection signal. It is thus connected to the control unit 24 driving the actuator 23. In a particular embodiment, the control unit 413 is integrated into a control unit 24. More precisely, the control unit 413 is arranged in order to control a movement of the connection part 22 from the retracted position to the proximity position, with a force the amplitude F1 of which is less than or equal to a maximum amplitude F1max and controlling a movement of the connection part 22 from the proximity position to the connection position, with a force the amplitude F2 of which is greater than or equal to the maximum amplitude F1max. More particularly, the amplitude F2 can be greater than a minimum amplitude F2min. The minimum amplitude F2min is greater than the maximum amplitude F1max. The minimum amplitude F2min is for example equal to 450 N and the maximum amplitude F1max is equal to 70 N. Thus, before any detection, i.e. between the retracted position and the proximity position, the maximum effort involved for the movement of the connection part 22 is relatively limited, thus preventing injuries or damage being caused in the case of insertion of a foreign body. However, after a first detection, i.e. between the proximity position and the connection position, the connection part 22 is moved with a greater force, allowing a correct coupling with the connection part 12.
In
Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without exceeding the scope of the invention. In particular, the connection part 12 is shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 1650071 | Jan 2016 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2016/081262 | 12/15/2016 | WO | 00 |
