GB2570870A

GB2570870A - An electric vehicle and a method of recharging an electric vehicle

Info

Publication number: GB2570870A
Application number: GB1801575.0A
Authority: GB
Inventors: Delafargue Antoine
Original assignee: Pilot Subs
Current assignee: Pilot Subs
Priority date: 2018-01-31
Filing date: 2018-01-31
Publication date: 2019-08-14
Also published as: GB201801575D0

Abstract

An electric vehicle (e.g. EV, BEV, HEV, PEV, PHEV) includes: at least one main rechargeable battery 1 that supplies electrical power to at least one electric motor via a circuit; and at least one backup, auxiliary battery 3 that connects to the circuit to provide additional electrical power to the motor(s) and is removably insertable into the vehicle, via a slot 5 in a side of the vehicle, to connect with the circuit. Each backup battery may be exchanged with a battery from a battery rack at a recharge station forecourt, wherein a trolley conveys a backup battery between the rack and the vehicle. The main battery is spaced from the ground by a first distance and each backup battery is spaced from the ground by a second distance that is greater than the first distance. A battery loading system may move the backup battery between: a loaded position, in which it is fully retained within the vehicle; and an unloaded position, in which it extends out of the slot. The rechargeable backup battery has front and rear parts that abut each other along an oblique surface, wherein frangible members that hold the front and rear parts together, break when the battery is subjected to an impulse, e.g. from a collision, allowing the parts to slide relative to one another.

Description

AN ELECTRIC VEHICLE AND A METHOD OF RECHARGING AN

ELECTRIC VEHICLE

The present invention relates generally to electric vehicles and a method of recharging such vehicles and finds particular, although not exclusive, utility in electric cars.

Electrically powered vehicles are increasingly considered as a viable technological alternative to internal combustion engines to moderate climate change and pollution. However, the rate of adoption of electric vehicles is penalized by the limited range of electric vehicles, which is due to the high cost and low energy density of most battery types compared to liquid hydrocarbon fuels.

To extend range, the most commonly proposed solutions involve charging stations. However, fast charging still requires at least 30 minutes of vehicle immobilization, which only partially recharges the battery, and subjects both the battery and the power grid to high peak currents and constraints. This will not be viable as the proportion of electric vehicles on the road increases, as the footprint required by charging infrastructure will significantly exceed that of conventional fuel stations.

Swappable batteries have long been considered as a faster alternative to recharging to extend the range of electric vehicles.

As batteries are heavy and bulky, it is desirable for them to be distributed as low as possible on the chassis for vehicle stability purposes. Hence, removal and replacement of the batteries requires access beneath the car, which involves a car elevation system and/or a system embedded underground.

According to a first aspect of the present invention, there is provided an electric vehicle comprising: at least one electric motor configured to propel the vehicle; at least one main rechargeable battery configured to supply electrical power to the at least one electric motor via a circuit; and at least one backup rechargeable battery removably connectable to the circuit to provide additional electrical power to the at least one electric motor, wherein the at least one backup rechargeable battery is removably insertable into the vehicle to connect to the circuit via a slot in a side of the vehicle.

In this way, removal and replacement of the whole propulsive battery pack of a vehicle is avoided, thus avoiding the need to access beneath a car. In contrast, the present invention permits the main rechargeable battery to be distributed as low as possible on the chassis for vehicle stability purposes, whilst permitting easy extraction/insertion of the backup rechargeable battery.

The electric vehicle may comprise a car, truck, van, lorry, motorbike, electric bike, moped, scooter, boat or any other suitable electric vehicle.

The or each electric motor may be configured to drive at least one wheel of the vehicle (e.g. one, two, three, four or six wheels) and/or a propeller, track or any other form of propulsion.

The or each main rechargeable battery and/or the or each backup rechargeable battery may comprise an electric-vehicle battery (EVB), deep-cycle battery, storage battery, secondary cell, accumulator and/or traction battery.

The or each main rechargeable battery may be located in a base of the vehicle; that is, the or each main rechargeable battery may be located as low as possible within the vehicle to achieve as low a centre of mass as possible, specifically spaced from the ground by a first distance.

The circuit may comprise a control system and/or user interface such that electrical power supplied to the at least one electric motor from the at least one main rechargeable battery can be varied.

The at least one backup rechargeable battery may have a capacity of at most 200% of a maximum capacity of the at least one main rechargeable battery, in particular at most 100%, more particularly at most 50%, for example at most 30%.

The at least one backup rechargeable battery may be removably connectable in that the at least one backup rechargeable battery may be electrically connectable to the circuit.

The circuit may be configured such that, upon connection to the circuit, the at least one backup rechargeable battery may provide additional electrical power (over and above that provided by the at least one main rechargeable battery) to the at least one electric motor directly and/or via the at least one main rechargeable battery; that is, the at least one backup rechargeable battery may be connectable to drive the motor directly and/or top-up the at least one main rechargeable battery. In this way, the at least one main rechargeable battery may be fully topped-up by sequential exchange of multiple backup rechargeable batteries.

In particular, the circuit may be configured such that either supply configuration is selectable and/or predetermined.

The at least one backup rechargeable battery may be removably insertable in that the at least one backup rechargeable battery may be fully removable from the vehicle and replaceable with an alternative backup rechargeable battery if desired.

The at least one backup rechargeable battery is not required for operation of the vehicle, but may be inserted to enable a driver to extend the range of the vehicle.

The slot may comprise an opening having a horizontal extent (in normal use) that is substantially larger than its vertical extent (again, in normal use). The horizontal extent may be at least 1.6 times the vertical extent, in particular at least twice the vertical extent, more particularly at least three times the vertical extent, for example at least 4, 5, 6 and/or 7 times the vertical extent.

The slot may have a vertical extent of between 5 and 20cm, in particular between 7 and 15cm, more particularly approximately 10cm. The slot may have a horizontal extent of between 50 and 150cm, in particular between 60 and 100 cm, more particularly between 70cm and 90cm, for example approximately 75cm.

The above discussion of dimensions may apply equally to those of the at least one backup rechargeable battery, mutatis mutandis, in which the at least one backup rechargeable battery may be substantially cuboidal in shape. That is, the at least one backup rechargeable battery may have a depth of between 50 and 150cm, in particular between 60 and 100 cm, more particularly between 70cm and 90cm, for example approximately 75cm.

The slot may be disposed in a front side of the vehicle, rear side of the vehicle, left-hand side of the vehicle and/or right-hand side of the vehicle. For example, the slot may be disposed substantially adjacent to a number plate, boot/hood, bonnet, or door of the vehicle, for instance immediately therebelow or (e.g. concealed) behind.

The at least one backup rechargeable battery may comprise only one, two, three, four or more backup rechargeable batteries, and/or the vehicle may comprise at least one slot for insertion of the at least one backup rechargeable battery therein, in particular only one slot, two, three, four or more slots.

In use, the or each main rechargeable battery may be spaced from the ground by a first distance and the or each backup rechargeable battery is spaced from the ground by a second distance greater than the first distance.

The electrical vehicle may further comprise a battery management system configured to monitor and/or control voltage and/or level of charge of the at least one main rechargeable battery and/or the at least one backup rechargeable battery.

For instance, the battery management system may be configured to favour discharging the at least one backup rechargeable battery over the at least one main rechargeable battery. Alternatively, the battery management system may be configured to favour transferring energy from the at least one backup rechargeable battery to the at least one main rechargeable battery while driving. In this way, drivers who may recharge their vehicles without immobilizing their vehicles for the duration of charging.

The electrical vehicle may further comprise a battery loading system configured to move the at least one backup rechargeable battery between a loaded position in which it is retained fully within the vehicle and is in electrical connection with the circuit and an unloaded position in which it extends at least partially out of the slot.

The slot maybe provided with a door, to prevent ingress of contaminants and/or to provide security against theft of the at least one backup rechargeable battery when the at least one backup rechargeable battery is in the loaded position. The door may be lockable. The door may be provided with a licence plate of the vehicle mounted thereon, or integrally formed therewith.

The battery loading system may comprise guide rails and/or wheels (for instance freely rotating and/or motor-driven) for engaging with the at least one backup rechargeable battery and move it between the loaded and unloaded positions. For instance, the backup battery may be provided with guide rails into which wheels on the chassis of the vehicle are inserted; alternatively or additionally, the backup battery may be provided with wheels which may be insertable into/onto guide rails mounted on the chassis of the vehicle. The battery loading system may be similar to the loading systems conventionally used in VHS machines.

The battery loading system may comprise a battery loading controller (for instance a microprocessor) configured to receive a signal from a user-interface and in response thereto optionally determine one or more statuses of the vehicle and determine whether said statuses are above a predetermined threshold and in response to determining that said one or more statuses are above the predetermined threshold activate unloading and/or loading of the at least one backup rechargeable battery. For instance, the statuses may relate to determining whether the vehicle is stopped and/or parked, determining an inclination of the vehicle to the horizontal, determining whether a force beyond a certain threshold is applied to the battery in a predetermined direction (for instance if due to an obstruction).

The user interface may be a user interface device such as a touch-screen or button, or may comprise a feedback signal from a sensor on the vehicle, for instance determine a force acting on the battery. For instance, the battery loading controller may be configured to engage loading if a force beyond a certain threshold is applied on the battery to push it into the slot.

The electrical vehicle may further comprise a locking system to secure the battery in the loaded position.

The locking system may comprise a male connector located on one of the at least one backup rechargeable battery and a chassis of the vehicle, and a matable female connector located on the other one of the at least one backup rechargeable battery and the chassis of the vehicle. The male and/or female connector may be rotatable such that in a relative first orientation, the male connector may be removably insertable within the female connector, and in a second relative orientation the male connector may not be inserted into or withdrawn from the female connector. In this way, rotating the male and/or female connector between the first and second relative orientations may act to lock and/or unlock the at least one backup rechargeable battery within the vehicle. The male members may have a transversely elongate tip and may be lockable when rotated relative to the female members by approximately 90 degrees.

The battery loading system may be further configured to lock and/or unlock the locking system, for instance in response to said signal.

The backup battery may be provided with a handle for manual manipulation thereof.

The backup battery may be provided with a protective casing to ensure its mechanical integrity during driving, loading, swapping and charging, and optionally ensuring an adequate thermal management.

The backup battery may be provided with an accelerometer configured to detect shocks which may affect the integrity of the battery.

The backup battery may be provided with an internal memory for storing usage data to ensure the highest reliability and optimize recharging and maintenance programs, and the usage data may be downloaded for analysis by a monitoring system upon recharge.

The backup battery may comprise a front part and a rear part configured to abut each other along an oblique surface. The surface may be a plane; that is, the surface may be flat and/or have zero curvature. However, in alternative embodiments, the surface may be curved, For example, the surface may have a Gaussian curvature of zero; that is, it may be neither locally convex nor concave, but may have a principle curvature in at least one direction at every point within the surface of zero. In particular, the surface may have a principle curvature in a first direction at all points within the surface of zero. The surface may have a cross-section at right angles to the first direction that is substantially uniform along the first direction. An example of such a curvature would be a corrugated surface; that is, having a series of parallel elongate peaks and troughs. In this way, the face of the front part at the surface and the face of the rear part at the surface may conform to one another. Accordingly, the front part and the rear part may slide relative to one another in the first direction; that is, whilst remaining within the surface.

Frangible members may be arranged to hold the front and rear parts together under tension extend across the oblique surface to prevent movement of the parts away from one another, but may be configured to shear apart when the front and rear parts are subjected to a force urging them together, whereupon they will slide relative to one another across the oblique surface.

According to a second aspect of the present invention, there is provided an electric vehicle charging system comprising the vehicle of the first aspect and a rack of backup rechargeable batteries located in a recharge station forecourt.

The rack may be provided with recharging sockets for charging the backup rechargeable batteries therein.

The racks may comprise a locking system to secure the batteries in the rack, the locking system may be substantially similar to the locking system of the vehicle.

The racks may comprise a battery holding system configured hold the batteries within the rack. The battery holding system may be configured to move at least one backup rechargeable battery between a securable position in which it is retained fully within the rack and can be secured and a loading position in which it extends at least partially out of the rack for subsequent loading into a vehicle. The battery holding system may comprise various the features of the battery loading system described above, mutatis mutandis.

The holding system may comprise an inventory and/or catalogue for recording the charge status, battery health, reference number, location, availability, rental status, purchaser identification, payment information, cost and/or any other suitable data. A control module may be provided to collect battery, charger and transaction data, and with an internet connection, and a transaction pad and screen to unlock a battery for swapping.

In this way, a user may purchase a backup battery from the rack for a rental period and/or may exchange a depleted backup battery for a charged backup battery.

The rack may be provided with an indicator light to show an availability and/or charger/charging status of a battery therein. Availability may be based on a recharge level, and pre-booking status, and whether expected battery demand versus available supply leaves room for certain batteries to be utilized for flexible reserve power for the power grid.

Batteries in the rack may be spaced apart to allow convective cooling thereof, and/or to provide access for conveyance machinery such as a trolley.

The electric vehicle charging system may further comprise a trolley for conveying a backup battery between the rack and the vehicle.

The trolley may be provided with at least two wheels, for example two, three or four wheels. Some or all of the wheels may be configured for universal movement; that is movement in substantially any lateral direction via a pivotable axis of rotation. Movement of the trolley may be powered and/or power-assisted.

The trolley may be provided with a mechanical lifting aid to raise or lower the vertical height of a battery thereon.

The trolley may comprise a battery holding system configured hold the batteries on the trolley. The battery holding system may be configured to move at least one backup rechargeable battery between a securable position in which it is retained fully on the trolley and can be secured and an unloading position in which it extends at least partially off the trolley for subsequent unloading. The battery holding system may comprise various the features of the battery loading system described above, mutatis mutandis.

The trolley may be provided with a handle for manual manipulation thereof. The trolley may be provided with user interface controls such as buttons and/or a touch screen.

The trolley may be powered from a mains supply, for example via a power cord, or may be powered from an internal (rechargeable) battery, or may be powered from the backup battery loaded thereon.

The trolley may comprise a battery supporting frame that may be guided along a vertical hoisting frame, optionally with an electric motor controlling displacement, such that cutting power to the motor may not lead to a sudden movement of the battery supporting frame. The battery supporting frame may be linked to the vertical hosting frame with springs to reduce the absolute magnitude of the force sensed by the motor. To prevent unlocking the male & female members when the battery is only supported on the trolley, control electronics inhibit the unlocking command if excessive weight is sensed on the lower part of the supporting frame.

According to a third aspect of the present invention, there is provided a method of charging extending the range of an electric vehicle comprising: providing the electric vehicle of the first aspect; and replacing the at least one backup rechargeable battery with an alternative rechargeable battery.

Electric vehicles are powered by batteries (electro-chemical cells), typically rechargeable batteries. The chemicals within such batteries can be dangerous, and are therefore contained within a robust structure that prevents damage to individual cells within the battery. Typically, an electric vehicle battery will comprise a robust housing in which are provided a plurality of electrical cells. To aid installation and replacement, all available cells are often placed within a single protective housing. In alternative arrangements, multiple protective housings may be provided, each containing a plurality of electrical cells. However, these housing(s) are usually shaped substantially as cuboid(s).

In a vehicle impact, such batteries cannot be placed in crumple zones of cars, as this would expose the batteries to undesirable damaging forces, as well as hindering the crumpling characteristics of the crumple zone itself. Accordingly, the present design of batteries limits the placement of such batteries within an electric vehicle, which can impact performance and handling characteristics of the vehicle.

According to a fourth aspect of the present invention, there is provided a rechargeable battery comprising a front part and a rear part configured to abut each other along an oblique surface, and frangible members arranged to hold the front and rear parts together.

The surface may be a plane; that is, the surface may be flat and/or have zero curvature. However, in alternative embodiments, the surface may be curved, For example, the surface may have a Gaussian curvature of zero; that is, it may be neither locally convex nor concave, but may have a principle curvature in at least one direction at every point within the surface of zero. In particular, the surface may have a principle curvature in a first direction at all points within the surface of zero. The surface may have a cross-section at right angles to the first direction that is substantially uniform along the first direction. An example of such a curvature would be a corrugated surface; that is, having a series of parallel elongate peaks and troughs. In this way, the face of the front part at the surface and the face of the rear part at the surface may conform to one another. Accordingly, the front part and the rear part may slide relative to one another in the first direction; that is, whilst remaining within the surface.

In this way, if the battery is subjected to an impulse, the frangible members may break, allowing the front part and rear part to slide along their common oblique surface relative to one another, preventing damage to the cells within each part.

The front and/or rear parts may comprise a plurality of cells therein. The front and/or rear parts may comprise front and/or rear part housings, respectively, which may be robust; that is, having a structure that is configured to protect the cells therein.

The housing(s) may be made of stronger construction than the surrounding structure/chassis of vehicles into which they are inserted, in the sense that when subjected to a collision originating from the side of the vehicle closest to the battery, for instance a rear-end collision for a rear facing battery port, the vehicle’s structure around the battery will undergo more deformation than each of the battery parts.

The housing(s) may be provided with external connectors to permit electrical communication between the cells therein and electrical circuitry outside the housing(s). The or each housing may comprise a front/rear wall that is substantially vertical, two opposing side walls that are each substantially vertical, a top surface that is substantially horizontal, and/or a bottom surface that is substantially horizontal. In this context, the terms horizontal and vertical, top and bottom, and/or side, front and rear refer to relative orientations of the or each housing. The or each housing may further comprise a respective rear/front wall that is orientated at an angle substantially different to that of the respective front/rear wall and/or the top and/or bottom surface(s), and furthermore that is substantially at right angles to the or each side wall. That is, the respective rear/front wall may comprise a surface that is oblique to the top and bottom surfaces and to the front/rear wall, whilst optionally being substantially perpendicular to the side walls. In an alternative embodiment, the rear/front wall(s) may also be oblique to the side wall(s).

The oblique surface may be at an angle between 20 and 70 degrees to the top surface, in particular between 30 and 60 degrees, more particularly between 40 and 50 degrees, for example approximately 45 degrees.

In particular, an incident force applied to the front part directly into (i.e. perpendicular to) the front wall would cause the front part to move rearward. However, the reactive force applied to the rear part through the oblique rear-front wall junction will be at an oblique angle to the incident force. This reactive force may act to move the rear part either up or down (depending on the slope of the oblique surface), either wholly or partially instead of a direct rearward motion. Similarly, the front part may move either down or up (again depending on the slope of the oblique surface), either wholly or partially instead of a direct rearward motion. It can be seen that a similar effect would occur if the incident force were applied to the rear part directly into (i.e. perpendicular to) the rear wall.

The parts may abut in the sense that they may be in direct physical contact with each other.

The frangible members may be configured to hold the parts together under tension, for instance by extending across the oblique surface to prevent movement of the parts away from one another, but may be configured to shear apart when the front and rear parts are subjected to a force urging them together, whereupon they will slide relative to one another across the oblique surface.

Alternatively or additionally, the frangible members may be configured to hold the parts together below some predetermined/predefined threshold incident force, to prevent accidental or undesired movement of the parts relative to one another, but may be configured to break / shear apart in response to an incident force above the predetermined/predefined threshold. For example, the threshold may be set to prevent damage to the cells within the housing(s), or may be set to prevent damage to adjacent vehicle components.

The frangible members may comprise bolts, pins, etc. and may extend across the oblique surface to prevent relative sliding of the front and rear parts (for example via the dovetail joint). The frangible members may be configured to break before damage to either the front or rear parts occurs in response to an impact. However, the frangible members may also be configured to be sufficiently strong to withstand normal operating conditions of the battery.

In particular, the frangible members may have sufficiently low shear strength to shear off in case of the application of the compressive force in the longitudinal direction of the vehicle, resulting from a vehicle collision. Hence, in case of collision, rather than collapsing against one another and damaging their internals, the two battery parts will slide one past the other along their oblique surface.

The frangible members may be a mere friction member, such that movement is not induced below the threshold incident force, but above that threshold movement is induced. That is, ‘frangible’ may not mean ‘break’ but may merely mean members configured to permit movement above a certain threshold only.

The front and rear parts may cooperate with one another across the oblique surface by virtue of at least one sliding dovetail joint. The sliding dovetail joint may have substantially any cross section, such as T-shaped, trapezoidal, etc.; however, the dovetail joint is configured such that a male portion of the sliding dovetail joint extends out of one of the front and rear parts from a relatively narrow base to a relatively broad head, and configured such that a female portion of the sliding dovetail joint extends into the other of the front and rear parts from a relatively narrow entrance to a relatively broad base. In this way, the male portion may be slide laterally into the female portion, but cannot be pulled directly out.

The sliding dovetail may extending the entire height of the oblique surface, or may merely extend a part of the way over the oblique surface, for example, at most 2%, 5%, 10%, 20%, 30% or 50% of the height.

Alternatively or additionally, the battery may comprises one or more (e.g. a plurality of) stops. In this way, relative movement of the front and rear parts may be limited to one direction within the oblique surface only.

The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

Figure 1 shows an electric vehicle.

Figure 2 shows a slot in the electric vehicle of figure 1, with a backup battery being removed therefrom.

Figure 3 shows a trolley configured to hold the backup battery of figure 2.

Figure 4 shows an exchange station for storage of a plurality of such backup batteries.

Figure 5 shows a backup battery.

The present invention will be described with respect to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. Each drawing may not include all of the features of the invention and therefore should not necessarily be considered to be an embodiment of the invention. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other orientations than described or illustrated herein.

It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Similarly, it is to be noticed that the term “connected”, used in the description, should not be interpreted as being restricted to direct connections only. Thus, the scope of the expression “a device A connected to a device B” should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may be a path including other devices or means. “Connected” may mean that two or more elements are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other. For instance, wireless connectivity is contemplated.

Reference throughout this specification to “an embodiment” or “an aspect” means that a particular feature, structure or characteristic described in connection with the embodiment or aspect is included in at least one embodiment or aspect of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, or “in an aspect” in various places throughout this specification are not necessarily all referring to the same embodiment or aspect, but may refer to different embodiments or aspects. Furthermore, the particular features, structures or characteristics of any embodiment or aspect of the invention may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments or aspects.

Similarly, it should be appreciated that in the description various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Moreover, the description of any individual drawing or aspect should not necessarily be considered to be an embodiment of the invention. Rather, as the following claims reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value.

The use of the term “at least one” may mean only one in certain circumstances. The use of the term “any” may mean “all” and/or “each” in certain circumstances.

The principles of the invention will now be described by a detailed description of at least one drawing relating to exemplary features. It is clear that other arrangements can be configured according to the knowledge of persons skilled in the art without departing from the underlying concept or technical teaching, the invention being limited only by the terms of the appended claims.

Figure 1 shows an electric vehicle having a main rechargeable battery 1 for providing motive power to the wheels, and two separate backup batteries 3 for extending the range of the vehicle. Each backup battery 3 may be removed from the vehicle in the respective directions indicated by the arrows.

Figure 2 shows a slot 5 in the electric vehicle of figure 1, with a backup battery 3 being removed therefrom. Part of the bodywork 7 of the vehicle is shown for exemplary purposes only. As is apparent from the figure, the battery 3 is configured for a close fit within the slot 5 in order to prevent introduction of extraneous foreign matter within the vehicle. In addition, a door 9 is provided to seal the slot 5 when the battery 3 is not being removed or installed. An identification plate 11 is provided on a front face of the battery 3, and may include a serial number, QR code, etc.

Guide rails in the form of a groove 13 are provided in the battery 3, and in the form of a support 15 on the chassis of the vehicle are provided to guide the battery 3 through the slot 5. Motorized wheels 16 are provided to engage with the battery 3 via the grooves 13.

Electrical contacts 17 are provided on the chassis for mating engagement with corresponding contacts (not shown) on a rear side of the battery 3. Male mechanical connectors 19 are provided on the chassis for engagement with female connectors 21 around the periphery of the battery 3. The male connectors 19 are rotatable about their longitudinal axis, such that they may be inserted into the female connectors 21 at a first orientation and when rotated to a second orientation cannot be removed.

Figure 3 shows a trolley configured to hold the backup battery 3 (shown in dashed lines for clarity). The trolley includes male connectors 19 for engagement in female connectors 21 on the front of the battery (not shown). In the figures the male connectors 19 on the chassis of the car and on the trolley are shown as identical, as are the female connectors 21 on the front and rear of the battery 3; however, alternative arrangements where each set of male connectors 19 only engages with the corresponding set of female connectors 21 are also envisaged. In any event, the male connectors 19 on the trolley lock the backup battery 3 onto the trolley via the contact panel 22.

An electrical contact 23 on the battery is shown in figure 3 for electrical connection to the contact 17 on the chassis of the vehicle in figure 2.

The trolley itself supports the battery 3 on an arm 25, the arm being movable vertically on a riser 27 (as indicated by the arrow). The riser is movable laterally on wheels/casters 29, which are preferably omni-directional; that is, may roll about a horizontal axis, which in turn may pivot about a vertical axis.

The trolley may be manoeuvred by a user using the handle 31, and the height of the contact panel 22 and arm 25 may be controlled using the user interface device 33.

A power cable 35 supplies power to the trolley from a mains supply.

Figure 4 shows an exchange station for storage of a plurality of such backup batteries 3, with a loading area 37 marked out in front. Vehicles and trolleys are not shown for clarity; however, the power cable 35 and swing armature thereof are illustrated.

Next to each battery 3 is an indicator 39, which may be a simple light indicating availability, or may for instance be an array of coloured lights indicating status (e.g. red: unavailable, green: available, blue: charging, etc.). Alternatively, the indicator 39 may be a display panel for conveying more complex information.

Control and monitoring equipment is provided in a housing 41, with a user interface 43 for purchasing and/or renting a battery 3, including payment means.

Figure 5 shows optional features of the backup battery 3. A perspective view is shown in (a) in which can be seen that the backup battery comprises a front part 45 and a rear part 47 configured to abut each other along an oblique surface 49.

The front 45 and rear 47 parts may be made of stronger construction than the surrounding structure/chassis of the vehicles, in the sense that when subjected to a collision originating from the side of the vehicle closest to the battery, for instance a rear-end collision for a rear facing battery port, the vehicle’s structure around the battery will undergo more deformation than each of the battery parts.

The front 45 and rear 47 parts may cooperate with one another across the oblique surface 49 by virtue of at least one sliding dovetail joint 51. The sliding dovetail joint 51 may have substantially any cross section, such as T-shaped, trapezoidal, etc.; however, the dovetail joint 51 is configured such that a male portion of the sliding dovetail joint extends out of one of the front 45 and rear 47 parts from a relatively narrow base to a relatively broad head, and configured such that a female portion of the sliding dovetail joint extends into the other of the front 45 and rear 47 parts from a relatively narrow entrance to a relatively broad base. In this way, the male portion may be slide laterally into the female portion, but cannot be pulled directly out.

In (b) a cross section of the battery is shown with the oblique surface 49 shown from top left to bottom right. Frangible members 53, for example bolts, extend across the oblique surface 49 to prevent relative sliding of the front 45 and rear 47 parts (via the dovetail joint 51). The frangible members 53 are configured to break before damage to either the front 45 or rear 47 parts occurs in response to an impact. However, the frangible members 53 are also configured to be sufficiently strong to withstand normal operating conditions of the battery 3.

In particular, the frangible members 53 have sufficiently low shear strength to shear off in case of the application of the compressive force in the longitudinal direction of the vehicle, resulting from a vehicle collision. Hence, in case of collision, rather than collapsing against one another and damaging their internals, the two battery parts will slide one past the other along their oblique surface 49.

Alternatively or additionally, the battery 3 may comprises a back stop step 55, and/or a set of T-shaped tie-ins 51, located at the lower and upper edge of the oblique surface 49 respectively. The T-shaped tie-ins 51 may be an alternative or additional feature to the sliding dovetail, in that they may merely be a small section of sliding dovetail rather than necessarily extending the entire height of the oblique surface 49. These extra features will specifically prevent the two battery parts from being sheared off by movement of the front 45 and rear 47 parts laterally away from each other, for instance during a swapping operation when the weight of the battery part that is free hanging exerts an extensional force along the shearable surface.

(c) shows a lateral force incident on the battery 3 in the direction of the arrow, with the front 45 and rear 47 parts sliding along the oblique surface 49 relative to one another. This minimizes the risk of internal battery cell damage, which might trigger fires, whilst ensuring that the energy absorptive properties of the vehicle in case of collision are not diminished by the presence of rigid battery elements.

Claims

1. An electric vehicle comprising:

at least one electric motor configured to propel the vehicle;

at least one main rechargeable battery configured to supply electrical power to the at least one electric motor via a circuit; and at least one backup rechargeable battery removably connectable to the circuit to provide additional electrical power to the at least one electric motor, wherein the at least one backup rechargeable battery is removably insertable into the vehicle to connect to the circuit via a slot in a side of the vehicle.

2. The electrical vehicle of claim 1, wherein, in use, the or each main rechargeable battery is spaced from the ground by a first distance and the or each backup rechargeable battery is spaced from the ground by a second distance greater than the first distance.

3. The electrical vehicle of claim 1 or claim 2, further comprising a battery management system configured to monitor and/or control voltage and/or level of charge of the at least one main rechargeable battery and/or the at least one backup rechargeable battery.

4. The electrical vehicle of any preceding claim, further comprising a battery loading system configured to move the at least one backup rechargeable battery between a loaded position in which it is retained fully within the vehicle and is in electrical connection with the circuit and an unloaded position in which it extends at least partially out of the slot.

5. The electrical vehicle of claim 4, further comprising a locking system to secure the battery in the loaded position.

6. An electric vehicle charging system comprising the vehicle of any preceding claim and a rack of backup rechargeable batteries located in a recharge station forecourt.

7.

The electric vehicle charging system of claim 6, further comprising a trolley for conveying a backup battery between the rack and the vehicle.

8. A method of charging extending the range of an electric vehicle comprising:

5 providing the electric vehicle of claim 1; and replacing the at least one backup rechargeable battery with an alternative rechargeable battery.

9. A rechargeable battery comprising a front part and a rear part configured to abut 10 each other along an oblique surface, and frangible members arranged to hold the front and rear parts together.