Abstract:
A replacement station for the traction batteries of electric vehicles, preferably of passenger vehicles, which are arranged such that they can be replaced from underneath, alongside a vehicle axis in the direction of travel, in the floor area of the electric vehicle. In order to replace the traction battery, the electric vehicle is positioned, guided by tracks, above a hatch which is provided in the floor of the replacement station, and the traction battery is replaced through the hatch. In order to considerably minimize the total time required for completely automatic replacement of the traction battery without any disturbances, and to maintain a high safety standard in operation during the process, the track guidance guides at least those wheels which are arranged on one longitudinal side of the electric vehicle and in that, during track guidance, the electric vehicle is moved automatically by a controlled external drive, which acts on the electric vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority, under 35 U.S.C. §119, of German patent application DE 10 2009 053 358.3, filed Nov. 17, 2009; the prior application is herewith incorporated by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    The invention relates to a replacement station for the traction batteries of electric vehicles, preferably of passenger vehicles, which are arranged such that they can be replaced from underneath, alongside a vehicle axis in the direction of travel, in the floor area of the electric vehicle. In order to replace the traction battery, the electric vehicle can be positioned, guided by tracks, above a hatch which is provided in the floor of the replacement station. The traction battery is then replaced through the hatch. 
         [0003]    The increasing efforts to save fossil energy sources and environmental protection reasons are leading to the introduction of electric vehicles on a large scale for individual transport, necessitating intelligent systems which will make it possible to considerably increase the previously restricted range of electrically powered vehicles. At the moment, vehicle range is considerably restricted by the limited storage capacities of the traction batteries used, in comparison to vehicles with internal combustion engines. Furthermore, at the end of their range, drained traction batteries require several hours to be recharged, and the unavailability of the vehicle resulting from this, even in the case of traction batteries with a rapid charging capability, is extremely disturbing, and is leading to the market reacting to pure electric vehicles with some restraint. 
         [0004]    Instead of this, hybrid vehicles are more frequently being used which in addition to the electrical drive, also have internal combustion engines which. Although the internal combustion engines increase the range of the vehicles, they still do not shorten the time to charge the traction batteries. 
         [0005]    In order to make electric vehicles more attractive for the users, and to avoid the described disadvantages, it has already been proposed that the time-consuming charging processes for the traction batteries be dispensed with and that, instead of this, the drained traction batteries be replaced by charged traction batteries. Systems such as these for replacement of traction batteries have already been known for a very long time, and were even used in the early twentieth century (cf. U.S. Pat. No. 1,362,019). Other replacement stations for traction batteries for electric vehicles are described in U.S. Pat. No. 5,612,606 and in German published patent application DE 42 29 687 A1. 
         [0006]    The last-mentioned document describes an automatic battery replacement station in which the electrically powered vehicles are positioned using a parking aid. The traction battery, which is arranged under the chassis, is then released by means of a handling apparatus and is lowered below the floor level in order to pass it by lateral movement under the floor to a charging and supply station. Already charged traction batteries are taken from a shelf storage system associated with the battery replacement station, are passed back on the return route, and are reinserted into the vehicle by means of the handling apparatus. It is intended to be possible to operate the known battery replacement station partially automatically. 
         [0007]    When drained traction batteries are replaced in replacement stations of the described type, the total time required between the electric vehicle entering the station and leaving the station with a full traction battery is a critical factor for the attractiveness of a system such as this. This time is influenced not only by the pure process of replacing the traction battery but also by the additional times which are required, for example, for the entrance of the electric vehicle into the replacement station, and for positioning in the replacement station. Rapid central positioning of the electric vehicle is therefore just as important as the positioning accuracy of the replacement apparatus under the traction battery, which is also critical for fully automatic replacement, in particular without any disturbances, of the traction battery. 
         [0008]    Although DE 42 29 687 A1 has already proposed a parking aid for the vehicle in the form of track grooves as known from lifting platforms and assembly pits, this, however, does not take into account the driving skill of the vehicle drivers or of the widely differing dimensions, in particular track widths and tire widths, of modern motor vehicles. Since, in order to increase the capacity, traction batteries are frequently very physically large and frequently occupy virtually the entire width of the electric vehicle, this additionally exacerbates the handling of the traction batteries, which are arranged under the vehicle and have to be removed through installation hatches, and the known battery replacement station does not take account of this. Furthermore, the known station ignores the safety aspects during replacement of the traction batteries through a hatch, under which there is a deep shaft which must be opened in order to replace the traction batteries. 
       SUMMARY OF THE INVENTION 
       [0009]    It is accordingly an object of the invention to provide a change station which overcomes a variety of disadvantages of the heretofore-known devices and methods of this general type and which provides for a replacement station of this generic type for the traction batteries of electric vehicles such that they can be handled safely and such that the total time required to replace the traction battery, in a fully automatic operation without any disturbances, calculated from the entrance to the exit of the electric vehicle, is substantially and considerably minimized. 
         [0010]    With the foregoing and other objects in view there is provided, in accordance with the invention, a replacement station for exchanging traction batteries of electric vehicles, wherein the batteries are arranged for replacement from underneath the vehicle, alongside a vehicle axis in a direction of travel, in a floor area of the electric vehicle, the replacement station comprising: 
         [0011]    a hatch provided in a floor of the replacement station and formed to have the electric vehicle disposed thereabove; 
         [0012]    a track guidance system for guiding the vehicle during positioning above said hatch, said track guidance being configured to guide at least those wheels that are arranged on one longitudinal side of the electric vehicle; 
         [0013]    a controlled external drive acting on the electric vehicle, at least during track guidance, for automatically moving the electric vehicle; and 
         [0014]    wherein the traction battery is replaced through said hatch after the vehicle has been positioned. 
         [0015]    In other words, the objects of the invention are achieved with a replacement station that has a track guidance system that guides at least those wheels which are arranged on one longitudinal side of the electric vehicle and in that, at least during track guidance, the electric vehicle is moved automatically by a controlled external drive, which acts on the electric vehicle. Since the driver of the electric vehicle no longer has to be involved in the process of moving and braking the vehicle, because the external drive carries out this function, this allows safe automatic operation, independently of possible errors by unskilled drivers. 
         [0016]    If, according to one refinement of the invention, the external drive is in the form of a towing chain, which acts on the wheels of the electric vehicle driving them forward in a similar manner to the towing chain in a drive-through car wash, and which transports the electric vehicle with the traction battery exactly to a position above the hatch, this allows the electric vehicle to be aligned quickly and without disturbances. 
         [0017]    According to one particularly advantageous refinement of the invention, the track guidance within the replacement station is adjustable laterally with respect to the longitudinal axis of the electric vehicle, with respect to the wheel width and/or track width of the electric vehicle, such that the traction battery of the electric vehicle can be positioned centrally above the hatch, irrespective of its wheel width and/or track width. The invention offers a solution which takes account of the widely differing driving capabilities of the car drivers on the one hand and the different tire width of a car type, and/or different track and axle separations of different car types. 
         [0018]    Preferably, the track guidance guides at least the wheels which are arranged on one longitudinal side of the electric vehicle in which case, according to a further refinement of the invention, the track guide is in the form of a guide rail with side guides on both sides, to which the flank areas of the guided wheels can be applied. In this way, at least the front wheel and the rear wheel on one vehicle side are aligned in a defined lateral position with respect to the longitudinal plane in which the hatch for replacement of the traction battery is located. The alignment of the vehicles with respect to the hatch can be designed appropriately by moving the track guide and/or side guide transversally with respect to its own longitudinal axis. 
         [0019]    One problem with track guides for electric vehicles is that the tire width can vary greatly even between vehicles which are physically the same. In order nevertheless to achieve a defined alignment with respect to the hatch, the invention proposes that the lateral distance between the side guides on both sides can be set to the width of the wheels or of the tires. 
         [0020]    Preferably, the track guidance and/or the side guide are/is set laterally on the basis of the already known vehicle dimension data and the already known position of the traction battery in the electric vehicle. The vehicle data can either be stored in the replacement station and can be called up by identification of the vehicle. Alternatively, according to the invention, before the electric vehicle is moved into the replacement station, the vehicle dimension data is recorded and is entered in a computer which controls the matching of the track guidance to the individual dimensions of the electric vehicle. 
         [0021]    In one development of the invention, aids are provided for initial positioning of the electric vehicle in front of the track guide. These aids, in addition to known visual guidance aids when driving the vehicle into the replacement station, can in the simplest case be represented by funnel-shaped widened areas at the start of the track guide or, according to another feature of the invention, may be in the form of movement platforms guided on the floor, on which the stationary electric vehicle can be moved by lateral movement of the platforms to a position which corresponds to the entrance position into the track guide. These aids mean that the electric vehicle need not be positioned very accurately initially; this is because the alignment is carried out by these aids. The correct position is always defined from the position of the traction battery with respect to the replacement mechanism. 
         [0022]    A fully automatic replacement station must be subject to relatively stringent safety requirements in order to prevent people from being injured during the replacement process. In particular, the hatch should be closed at least whenever no electric vehicle is above it, in order that no object or living being, but in particular no person, can fall into the pit of the handling apparatus. The size required for the installation opening additionally makes it necessary to have the capability to drive over at least sub-areas of the closed flap. A further feature of the invention accordingly provides that the hatch is closed, and can possibly be driven on, before the positioning of the electric vehicle, and can be opened once the electric vehicle has been positioned exactly above the hatch. 
         [0023]    For this purpose, the invention provides that the hatch can be closed by a plurality of flaps, which can pivot about respective horizontal pivoting axes, which can be opened as required for replacement of the traction battery, as soon as the electric vehicle is in the exactly aligned position above the hatch. 
         [0024]    The required size of the hatch necessitates safety precautions against unauthorized access. Without such precautions, it would be possible for gaps to remain between the vehicle and the hatch even when vehicles are located in the replacement position, through which children, animals or objects could fall into the pit. In order to prevent this, according to the invention, edge areas of the hatch form fence-like protection (i.e., a protective fence) when the pivoted flaps are in the open position. 
         [0025]    The flaps are preferably designed such that subsections of the pivoted flaps which project upward above the floor level form the protective fence for the edge areas of the hatch when in their open positions. This ensures that the fence-like protection is formed naturally as soon as the flap is opened. 
         [0026]    Depending on the type of vehicle and battery in use, the traction battery is located between the axles of the vehicle, or else shortly behind the rear axle. In many cases, the width of the traction battery is greater than the distance between the insides of the wheels on both sides. In order to replace the drained traction battery, the open hatch must have an unobstructed width which is greater than the track width, and this means that it is necessary to be able to drive the electric vehicle at least over sub-areas of the closed hatch. In order to make this possible, it is proposed that if the hatch width extends into the driving track of the electric vehicle, flaps are provided which can be moved over on both sides in the edge area of the hatch and can be pivoted about pivoting axes, which are arranged parallel to the vehicle longitudinal direction, after said flaps have been moved over and before the replacement of the traction battery. 
         [0027]    In order to drive over them, when the flaps are closed, their upper faces each form a flat movement path for the electric vehicle, and in that, at least that area of the lower faces of each of the two flaps facing the edge of the hatch is in the form of a cylindrical segment, whose longitudinal center axis in each case coincides with the pivoting axis of the flap. When the flap is being pivoted to the open position of the hatch, that cylindrical segment which faces outward is pivoted upward, and forms the fence-like protection for the opening of the hatch. The cylindrical segment safely closes the gap which remains after the flap has been pivoted, because of the separation required between the pivoting axis and the edge of the hatch, and keeps this gap closed even during the pivoting movement, such that no object can be trapped, even during pivoting. 
         [0028]    In one advantageous refinement of the invention, at least one and preferably two further flaps, which can pivot, is or are provided in order to close the hatch, whose pivoting axes which run parallel to the edge area of the hatch and transversely with respect to the vehicle longitudinal axis are positioned with respect to the flap or flaps such that a subsection of each flap projects above the floor level in the immediate edge area of the hatch, when pivoted to the open position, and forms the fence-like protection for the hatch. By splitting the flaps into those flaps whose pivoting axes run in the vehicle longitudinal direction and those whose pivoting axes run transversely with respect to this, the hatch can be completely closed, while creating the fence-like protection around the hatch during opening, by appropriate arrangement of the pivoting axes on the flap. 
         [0029]    For this purpose, those subsections of each flap which project upward are likewise provided with cylindrical segments on their lower faces, which cylindrical segments form the fence-like protection, while at the same time closing the gap between the opened flap and the edge area of the hatch, when the flap is in the open position. 
         [0030]    All means and measures are provided such that the traction batteries can be replaced and the flaps can be operated in an automated form. 
         [0031]    In one alternative invention, the invention makes it possible for the fence-like protection for the hatch to be formed by a flexible bellows or a flexible-tube bead which clasps the edges of the hatch, and forms the fence-like protection for the hatch opening, when in the activated position. A bellows or flexible tube such as this can be inflated as soon as the hatch is opened, thus providing protection against anything falling in. The bellows or the bead can be folded by allowing air to escape when the hatch is closed, such that the electric vehicle drive on to it. Both measures, the flaps which can be pivoted and are provided for closing and opening the hatch, and the flexible bellows surrounding the open hatch, or the flexible-tube bead, can be used in conjunction with one another. 
         [0032]    The present invention offers a range of advantages. For example, the proposed measures make it possible to shorten the time required to replace a traction battery by several times, because sensible devices allow fully automatic operation. Different vehicles with different track widths and/or different tire widths can be handled by a single mechanism, which at the same time compensates for position tolerances. 
         [0033]    Freedom from disturbances is largely ensured by the driver of the electric vehicle no longer being involved in the automatic process after driving into the replacement station; the position and the replacement of the traction battery are carried out under process control, taking account of the specific vehicle dimensions, if appropriate after correction of the track guidance or the vehicle position before entering the replacement station. In order to achieve a high safety standard, measures are provided within the automatic process to prevent hazards to people. 
         [0034]    Other features which are considered as characteristic for the invention are set forth in the appended claims. 
         [0035]    Although the invention is illustrated and described herein as embodied in a replacement station for the traction batteries of electric vehicles, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
         [0036]    The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0037]      FIG. 1  shows a plan view of a replacement station according to the invention; 
           [0038]      FIG. 2  is a vertical section through a replacement station according to the invention, as shown in  FIG. 1 ; 
           [0039]      FIG. 3  shows a plan view of an electric vehicle as it is related to the invention; 
           [0040]      FIG. 4  shows a rear view of an electric vehicle above the hatch; 
           [0041]      FIG. 5  shows the functional layout of a replacement station; and 
           [0042]      FIGS. 6-8  show schematic views of the open and closed hatches. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0043]    Referring now to the figures of the drawing in detail and first, particularly, to  FIG. 1  thereof, there is shown a highly schematic illustration of a replacement station  1  for the traction batteries of electric vehicles, showing a building  2  which is subdivided into two rooms. The electric vehicle can be driven into the right-hand room  3  in the drawing figure, while a shelf system  5 , which is not described in any more detail, with an associated handling apparatus for storing and handling the traction batteries  6  is accommodated in the left-hand room  4  in the drawing. The traction batteries  6  are each arranged in replacement frames  7 , and are replaced together with them. The replacement is carried out through a hatch in the floor, which can be seen at  8  in the right-hand room  3 . When there is no electric vehicle in the room, the hatch  8  is closed for safety reasons, and can be opened manually or automatically, as will also be explained later. 
         [0044]    Traction batteries for electric vehicles or hybrid vehicles are also referred to as electric vehicle batteries (EVB) and electric vehicles are also referred to as propulsion battery electric vehicles (BEV). 
         [0045]      FIG. 1  also shows the track guide  9  for the electric vehicle  14  in the right-hand room  3 , which track guide  9  is provided with a towing chain  10  in the exemplary embodiment. As known from car washes, the endlessly running towing chain engages behind at least one of the wheels  24  of the electric vehicle  14 , and moves it through the track guide  9 . In the exemplary embodiment, the track guide  9  is provided only for the wheels  24  of one side of the vehicle; the track guide itself consists of guide rails with side guides  11 , to which the flank areas of the guided wheels can be applied. The position of the towing chain  10  is controlled as a function of the vehicle, and positions the electric vehicle such that the traction battery  6  to be replaced is positioned exactly above the initially still closed hatch  8 . 
         [0046]    As can be seen in  FIG. 2 , a handling apparatus  12  is arranged under the hatch  8  and allows the traction battery  6  to be removed downward when the hatch  8  is open, and to be transported by lateral movement (direction of the arrow  13 ) into the area of the shelf system  5 , where the discharged traction battery  6  is replaced by a charged battery. In this case, it is always absolutely essential that the handling apparatus  12  and the traction battery  6  be positioned exactly for replacement, in order to allow the traction battery  6  to be removed and fitted together with its frame  7 . 
         [0047]    As can be seen in  FIG. 3 , which shows a schematic plan view of an electric vehicle  14 , the traction battery  6  is in principle arranged in a replaceable frame  7 , which is attached to four attachment points  7   a  to  7   d  under the electric vehicle  14 , behind the wheels  24  on the rear axle in the direction of travel. In order to fully utilize the capacity of the traction battery  6 , it is relatively large, as a result of which the replaceable frame  7  is broader than the track width of the electric vehicle  14 . This means that a sufficiently large unobstructed space must be provided within the hatch in order to replace the traction battery  6  through the hatch  8 , and in the example this extends into the movement path of the electric vehicle  14 . However, for safety reasons, it must be possible to close this area of the hatch  8  at least for the entrance of the electric vehicle  14 . 
         [0048]      FIG. 4  shows a schematic rear view of the electric vehicle  14  positioned above the hatch  8 , having been moved to this position above flaps  15  which have a semicircular cross section. In order to allow the electric vehicle  14  to enter, the flaps close at least that part of the hatch  8  which extends into the movement path of the electric vehicle  14 . The flaps  15  can pivot, as will also be explained later. 
         [0049]      FIG. 5  once again shows a schematic plan view of the replacement station  1  in its totality. The electric vehicle  14  is in front of the entrance to the replacement station, from where it can communicate with the computer system for the automatic station. The driver of the electric vehicle  14  registers on a terminal  16  before entering the replacement station  1 . Vehicle data which is stored in the computer, has previously been measured or is entered in the terminal is first of all checked to determine whether the track width of the electric vehicle  14  will pass over the hatch opening, that is to say whether the traction battery can be positioned exactly above the hatch  8  once the electric vehicle  14  has been moved in. Changes to this position can be carried out by moving the track guide  9  in its totality, as indicated by the double-headed arrow  17 , transversely with respect to the longitudinal axis of the electric vehicle  14 , such that the longitudinal axis of the electric vehicle  14  is moved laterally as appropriate. A similar adjustment process is carried out for the tire width of the electric vehicle  14 , by laterally moving at least one of the side guides  11  of the track guide  9 , as indicated by the arrow  18 , and setting it to a width in which the side flanks of the tires of the electric vehicle  14  rest on the side guides  11  on both sides, such that they are guided exactly. 
         [0050]    The double-headed arrow  13  in  FIG. 5  likewise symbolizes that a handling apparatus ( 12  in  FIG. 2 ), by means of which the traction batteries  6  can be replaced, can be moved under the floor in a passage  19  which connects the hatch  8  to the shelf store  5 . The shelf store  5  is itself controlled by a shaft controller, which is not illustrated, whose function need not be described any further here. 
         [0051]    For safety reasons, the replacement station  1  provides for the hatch  8  through which the traction battery  6  is replaced to be closed when no electric vehicle  14  has entered. As soon as the electric vehicle  14  is positioned above the hatch  8 , the latter is opened, as will be described in the following text. 
         [0052]      FIGS. 6 to 8  illustrate the individual steps for opening the hatch  8 , in which case the upper drawing figure in each case shows a highly schematic plan view of the area of the hatch  8 , and the lower illustration in each case shows a cross section through the hatch  8 , on a vertical section plane behind the rear tire of the electric vehicle  14 . The plan view in the upper illustration in  FIG. 6  shows four flaps  20 ,  21 ,  22 ,  23 , by means of which the hatch  8  is closed. Each of the four flaps  20  to  23  can pivot about a horizontal axis  20   a ,  21   a ,  22   a  and  23   a  (running on the plane of the drawing). The curved arrows  22   b  and  23   b  in the two side flaps  22  and  23  are intended to show that the flaps  22  and  23  can be pivoted about their axes  22   a  and  22   b  at a time after the track-guided entrance of the electric vehicle  14  into the battery replacement position, in order to allow the free space required at the side for replacement of the traction battery  6  together with its replaceable frame  7 . The two side flaps  22  and  23  are arranged behind the rear wheels  24  in the area of the track of the electric vehicle  14 , and allow the electric vehicle  14  to drive over them when the flaps  22  and  23  are in the closed position. 
         [0053]    This situation is illustrated in the lower drawing in  FIG. 6 , which also shows that the side flaps  22  and  23  are half-cylindrical  25  (with a semicircular cross section) on their lower faces, which on the one hand provides robustness for driving over these flaps  22  and  23 , while on the other hand ensuring that the gap to the edge  8   a  of the hatch  8  remains closed when the flaps  22  and  23  are being opened, as is shown in the lower illustration in  FIG. 7 . 
         [0054]    As can be seen in  FIG. 7 , after the electric vehicle  14  has entered, the flaps have been pivoted through 45° about their axes  22   a  and  23   a , as a result of which the upper faces  22   c  and  23   c  of the flaps  22  and  23  which can be driven on are now positioned more vertically, and the opening of the hatch  8  has been considerably enlarged. At the same time or in a second step, the two other flaps  20  and  21  are pivoted about their pivoting axes  20   a  and  21   a  as indicated by the arrows  25  and  26 , in order to also open the larger part of the hatch  8 . The pivoting axes  20   a  and  21   a  of the flaps are arranged such that these flaps  20  and  21  also provide fence-like protection for the hatch opening, simply by being rotated through 45° to a vertical position. As can be seen in the upper illustration in  FIG. 8 , this now results in an opening of adequate size to install and remove the traction battery  6  with its replaceable frame  7 . 
         [0055]    As is shown in the lower illustration in  FIG. 8 , after the pivoting of the flaps  20 , a sub-area of the flap  20  has been positioned at the top in the direction of the bottom of the vehicle, as a consequence of the sensible arrangement of the pivoting axis  20   a , and projects beyond the edge  8   a  of the hatch  8 , thus forming the safety fence. This is also done with the second flap  21 , which is illustrated only by dashed lines in the lower part of  FIG. 8  because it is concealed by the front flap  20 . The flap  21  also pivots about a sensibly arranged pivoting axis  21   a , as a result of which that part of the flap  21  which projects upward beyond the edge  8   a  of the hatch  8  forms fence-like protection for the hatch  8 , to prevent people and objects falling into it. 
         [0056]    Together with the side flaps  22  and  23 , which are likewise pivoted to a vertical position, the flaps  20  and  21  form a virtually complete fence around the hatch  8  when the hatch  8  is open, preventing objects or living beings from falling into the shaft under the hatch. The sub-areas of the flaps  20  and  21  which project beyond the hatch edge  8   a  are preferably likewise half-cylindrical or quarter-cylindrical (this cannot be seen in the view in  FIG. 8 ), as a result of which, the gap between the flap  20  and/or  21  and the hatch  8  is also closed in the pivoted position here.