DESC:Field of the Invention
[001] This invention relates to electric vehicles and more particularly to a frame
structure allowing packaging of one or more batteries within electric vehicles,
particularly 2 wheeler (2W) vehicles.
Background to the Invention
[002] A strong trend to electric vehicle manufacture and use is now becoming evident
as concerns with climate change and availability of fossil fuels become evident. Electric
vehicles include a number of batteries including a large number of electric cells. The
number of batteries required for an application is driven largely by the required vehicle
range. At the present time, readily available batteries remain bulky and this may limit
their use particularly where desired vehicle range conflicts with small vehicle size.
[003] For example, small vehicles which currently operate using liquid and gaseous
hydrocarbon fuels could advantageously be shifted to electric motor prime movers to
reduce emissions. An initial trend to reduced emission prime movers has involved
transition from petrol operated engines to gaseous fuelled engines, for example of the
LPG or CNG type. This has reduced emissions. However, proposed changes in
regulations, for example in India, is driving a shift to electrically powered vehicles. The
timeline for such shift is short and there are obvious difficulties in reconfiguring a vehicle
fleet to operate with electric motors. Vehicle re-design and re-configuration of
manufacturing plants for electric vehicle manufacture is a potentially time consuming
and costly exercise. Yet it is desirable to meet directives/focus set by the Government
of various countries.
[004] Batteries are typically expensive, are typically (though not always) intended to be
used in groups and are typically intended to be rechargeable. This gives rise to two
problems. Firstly, batteries are subject to theft and it would be desirable to avoid this
with a number of options for anti-theft protection being available. Secondly, the expense
of high quality batteries may also create a temptation to replace these with inferior
versions which may not include the safety features described below. Battery security is
particularly an issue for 2W vehicles such as motorcycles and scooters. However, there
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are other non-enclosed electrical vehicle types, such as quad bikes and other all terrain
vehicles (ATVs), and battery security may equally be an issue with such vehicle types.
[005] Further, a battery needs to be safely and securely mounted on the vehicle such
that it is locked in the correct position such that no movement is allowed in any direction
due to vibrations produced during vehicle operation. Use of separate battery box for
securely mounting the battery may be employed for securely mounting the batteries.
However, such battery box are bulky and occupies more space. Therefore, the floor
space/ leg space and storage space both are compromised which is one of the
essential requirement of two wheeled vehicle. The battery is one of the heaviest
components in a vehicle. In a two wheeled vehicle, equal weight distribution along the
vehicle is an important criterion since a driver needs to balance the weight in order to
balance the vehicle during driving. If the weight distribution within a vehicle is uneven
then it becomes difficult for driver to maintain the balance which can ultimately lead to
unsafe conditions. Therefore, a battery also needs to be located such that there will not
be any uneven load acting on vehicle during operation.
[006] In this regard, a battery typically being a heavier component, its positioning has a
major contribution in deciding overall centre of gravity (CG) of the vehicle. For efficient
operation it is always better if the CG of vehicle is shifted towards downward side of
vehicle. It also improves vehicle handling, safety and driving comfort. However, a major
challenge in shifting the battery toward downward side is swing arm has to be shifted
backward which increases overall length of vehicle. The size of the battery is another
important parameter which decides the capacity of a vehicle. The larger the capacity of
a vehicle, the larger the size of the battery.
[007] At the same time, another important component for a vehicle is the storage box is
typically provided in two-wheeled vehicle to store any articles. Storage space provided
in the storage box is also an important feature of any two-wheeled vehicle. The size and
mounting position of a battery and other associated components desirably should not
compromise space provided in the storage box even given the requirements for
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sufficient space to be available for securely mounting other associated components
such as charger, Motor Control Unit (MCU), Auxiliary Battery etc.
[008] The vehicle frame plays an important role in mounting a battery and associated
components and, evidently, considering the above requirements, it is challenging to
provide a frame structure for a two wheeled vehicle which can safely and securely
mount battery and other associated components without compromising vehicle
efficiency, safety driving comfort and the space for a storage box in an electric vehicle.
[009] It is an object of the present invention to provide a frame for an electric vehicle
which enables convenient and secure packaging of a vehicle battery and other
associated components.
[010] Another object of present invention is to provide a frame with battery mounting
position such that battery does not exert any imbalance force with expected
improvement in overall efficiency of an electric vehicle with driving comfort.
[011] Yet another object of the present invention is to provide a frame for an electric
vehicle which provides a convenient and compact and less bulky packaging
arrangement for battery and associated components such that floor space/ leg space
and storage space are not compromised.
Summary of the Invention
[012] With this object in view, the present invention provides a frame for an electric
vehicle comprising:
at least one head tube extending from a head pipe and at least two rear tubes extending
rearwardly from the head tube;
an electric battery module preferably used as power source for powering the electric
vehicle comprising at least one battery located below said rear tubes;
a protective frame structure for securely mounting said battery module;
wherein said protective frame structure for said electric battery module is fixed
substantially centrally and downwardly of said rear tubes of said frame and said battery
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module is locked to the protective frame structure from front and rear side of the battery
module.
[013] Conveniently, the protective frame structure includes plurality of cross members
connected to the rear tubes for structural purposes and also to allow secure and
convenient fixing of the electric battery module. At least one cross member is used for
connecting the rear tubes to create protective frame structure. Front and/or rear
connecting cross members would typically be employed dependent on design
considerations in terms of strength and components to be included, with a front cross
member connecting the rear tubes towards the front of the vehicle and a rear cross
member connecting the rear tubes towards the rear of the vehicle to support the electric
battery module. Such cross member(s) are preferably connected to the electric battery
module by suitable mounting means such as a mounting bracket. The front cross
member may extend substantially horizontally over a top surface of the battery to
restrict any vertical movement of the electric battery module. The rear cross member
may be connected to the rear tubes proximate a rear side of the frame and conveniently
extending downwardly from the rear tubes. A bottom cross-member is provided which
connects the two rear tubes. The bottom cross member is connected to the rear cross
member using connecting members in substantially horizontal direction to create a
platform on which battery can securely reside and held in position with locking means. ,
with the rear connecting member. A guiding means may be provided on the cross
members of the protective frame structure and/ or on the battery module for
conveniently mounting and removing the battery from the protective frame structure.
The guiding means may be in the form of guiding rails. The battery may be removed
from either side, the back side or central front side of the vehicle for charging or
swapping purposes.
[014] The electric battery module is connected to the protective frame structure with
locking means from front side and from rear side with the objects of minimising
vibration, loosening of the electric battery module from the frame resulting in either or
both of vertical and lateral movement and prevention of theft. Suitable locking means/
brackets may be provided on the front and rear side of the battery module. The battery
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is securely mounted in the protective frame with the help of locking means therefore; no
separate battery box is required for mounting the battery module securely thereby not
compromising the storage space provided in the storage box. The locking means
provided on the rear side of the battery module including a rear mounting bracket used
to lock the battery position from rear side by clamping said rear mounting bracket to the
side brackets from both sides of the battery module and further locked by clamping the
battery module to the side brackets using a bolt provided in a groove on the battery
module wherein; said side brackets are fixed to protective frame structure. The battery
securing structure conveniently includes an opening to enable access for the battery
module prior to connection, this opening preferably being on a rear side of the battery.
The rear side access to the battery makes battery removing operation difficult thereby
providing more protection from theft perspective. Horizontal location of the battery is
thus preferred though vertical positioning may be used. Vibration isolating elements are
desirably placed between the electric battery module and the battery securing structure
to reduce vibrations being transmitted to the electric battery module and reducing user
comfort. Preferably, the electric battery module comprises a single battery; however, a
battery module comprising a plurality of batteries may be used based on power
requirements, vehicle design parameters and availability of space.
[015] The electric battery module is a relatively heavy vehicle component. For a two
wheeled vehicle, a substantially equal weight distribution along the length of the vehicle
is highly desirable to enable a driver to balance weight distribution in order to balance
the vehicle during driving. An uneven weight distribution within the vehicle, though
possible, makes it difficult for a driver to maintain vehicle balance which can ultimately
lead to unsafe conditions. Ideally, the battery or battery module is located centrally
along the width of the vehicle, preferably at a central location along the length of the
vehicle. The position of the battery plays an important role in defining the centre of
gravity (CG) of the vehicle so where the battery is positioned in a downward position,
desirably on a central lower side of the vehicle, shifting the CG of vehicle to
substantially the same location is advantageous. Such CG location helps in improving
overall efficiency of the vehicle also provides driving stability, safety and better handling
of the vehicle. The battery module is packaged such that it does not extend forwardly
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beyond the dimensions of storage box when viewed from side of the vehicle. This
ensure that the floor space/ leg space and storage space are not compromised.
Another advantage of such battery positioning centrally of the vehicle and centrally to
the major portion of the vehicle electrical components is convenient positioning for wire
harness routing. Further, since the battery is located in such a downward position, the
design length of a swing arm increases. However, this problem is addressed by
mounting motor-transmission assembly on swing arm with a casing for motortransmission
which itself acts as the required swing arm. Therefore the need of
separate swing arm is eliminated and it helps in achieving the compact packaging.
[016] Conveniently, a storage box is provided enable storage of articles including
larger size articles such as a helmet. Such storage is separate to battery storage and
the storage box is not directly rested on the battery surface or on the protective frame
structure of battery. This assists in preventing damage to the battery or battery module.
[017] Conveniently, the head pipe of vehicle frame allows mounting of the handle bar
and steering assembly and at least one head tube extends from the head pipe in a
rearward and downward. The head tube of the vehicle frame is further provided with a
cross member which may be an integral part of the head tube or separately fixed to the
head tube. Preferably, two rear tubes are attached to the head tube, the rear tubes
extending in the rear direction of the frame. At least two longitudinal frame members
may be provided on the cross member. The longitudinal members may be substantially
horizontal and parallel to the horizontal portion of each of the two rear tubes. The
horizontal longitudinal members and horizontal portions of the rear tubes allow
mounting of at least one foot panel. One foot panel may be mounted on top of the
longitudinal members from top side while a further foot panel may be mounted on the
bottom of the longitudinal members. The respective sides of the foot panels are
desirably covered with side members, conveniently creating a hollow space between
the two foot panels which is advantageously utilized for various purposes, such as
battery cooling, accommodating other components etc. as described below.
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[018] During operation (charging/discharging), battery temperature increases. In order
to get the maximum efficiency of the battery and to prolong battery life, the battery is
maintained at a desired temperature. Ideally, battery operation is stopped if battery
temperature exceeds a pre-determined limit. Various battery heating and cooling
options are available with air cooling systems being preferred. Cooling requirement will
be more typical and to this end the battery is conveniently provided with a ram air
cooling means, with front body panel(s) being configured with one or more vents so that
ram air (i.e. the air flow through the vehicle during forward motion) flows over the battery
and cools the battery.
[019] The front body panel or guard may accommodate a cooling air duct
communicating with the vents and desirably the above described space between the
floor panels. Ram air entering through the vents then flows through the duct and into the
hollow space between the floor panels to be guided by air guiding means towards the
battery for cooling purposes, the components forming an air cooling system. The air
guiding means is conveniently provided on the bottom floor panel. The air cooling
system may further include air passage(s) directing air towards a targeted area of the
battery surface to achieve effective cooling.
[020] Further the hollow space created in the body panel is advantageously utilized for
placing various electrical and electronic components such as auxiliary battery, wiring
harness etc. which hides the wires and improves aesthetics of the vehicle. It also keeps
the wire connections safe from any external threats.
[021] The frame according to the present invention also provides convenient mounting
means for other associated components such as Charger, Connectivity box, Motor
control unit, DC-DC Converter etc. which helps in optimum packaging of components in
an electric vehicle. The rear tube is provided with mounting means for mounting motor
control unit (MCU 100) such that the MCU is mounted proximate to the electric battery
module on the left hand side of the vehicle.
[022] The MCU is configured to control the amount of torque to be produced by an
electric motor by controlling the amount of current/ voltage supplied based on at least
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one vehicle operating condition wherein; the amount of current/ voltage to be supplied
to the electric motor is decided based on a basic map of the amount of power to be
supplied to the electric motor to generate required torque as a function of selected
vehicle conditions including present vehicle speed and/ or accelerator pedal or grip
position.
[023] The rear tube is provided with a mounting provision for mounting a DC-DC
converter at the end of the rear tubes.
[024] The head pipe is provided with mounting provision for mounting a connectivity
box on the front side of the vehicle wherein; the connectivity box is configured to receive
the information including battery information, vehicle speed, distance travelled, driving
pattern, vehicle location, accident information and further configured to store and share
the information with external device over suitable communication network including Wi-
Fi, Bluetooth, Internet or telecommunication network.
[025] The rear tube is provided with a mounting provision for mounting a charger unit
used for charging battery module on right hand side of the vehicle.
[026] The battery module is charged on board the vehicle using a charging cable to
connect the charger to external supply through a charging point wherein; the charging
point is provided on the rear end of the vehicle below seat such that the charging cable
remains plugged and charges the battery even if the seat is closed and locked.
Short Description of the Drawings
[027] The electric vehicle of the present invention may be more fully understood from
the following description of preferred embodiments thereof, made with reference to the
accompanying drawings in which:
[028] Fig. 1 is a partial isometric view of an electric vehicle according to a first
embodiment of the present invention.
[029] Fig. 2 is a partial isometric view of the frame of the electric vehicle of Fig. 1.
[030] Fig. 3 is a partial side view of the frame of the electric vehicle of Fig. 1.
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[031] Fig 4 is a partial isometric view of the frame of Figs. 2 and 3 showing the
relationship between the rear frame portion and a battery for the electric vehicle.
[032] Fig 4(a) is a partial isometric view of the protective frame structure showing
clamping arrangement of rear mounting bracket of Fig. 4.
[033] Fig. 5 is a partial plan view of the electric vehicle shown in Fig. 1.
[034] Fig. 6 is an isometric view of the frame of the electric vehicle shown in Fig. 1
[035] Fig. 7 is an isometric view of the frame from rear side of the electric vehicle
shown in Fig. 1
[036] Fig. 8 is a detail view of the front body panel of the electric vehicle shown in Figs.
1 and 5.
[037] Fig. 9 is a schematic side view of the front portion of the electric vehicle of Fig. 1.
[038] Fig. 10 is a partial front view of the electric vehicle of Figs. 1 and 5.
[039] Fig. 11 is a partial side view of the electric vehicle of Figs. 1 and 5.
[040] Fig. 12 is a first detail side view projected from Fig. 9 showing motor control unit,
DC-DC converter, motor transmission assembly and shock absorber in relation to the
rear frame portion of the electric vehicle of Figs. 1 and 5.
[041] Fig. 13 is a second detail side view projected from Fig. 9 showing motor control
unit, shock absorber and charging point arrangement.
[042] Fig. 14(a) is a schematic side view of the rear portion of the electric vehicle of
Figs. 1 and 5 illustrating mounting of charger unit, DC-DC convertor according to
another embodiment of invention.
[043] Fig. 14(b) is a schematic rear view of the rear portion of the electric vehicle of
Figs. 1 and 5 illustrating mounting of charger unit, DC-DC convertor according to
another embodiment of invention.
[044] Fig. 15 is a schematic isometric view of the rear portion of the electric vehicle of
Figs. 1 and 5.
Description of Preferred Embodiment of the Invention
[045] Referring now to Figs. 1, 5 and 7, there is shown an electric vehicle 10 suitable
for use as a commuter vehicle and having a frame 11 having a head pipe 12; head
tubes 12A, at least two rear tubes 13. Frame 11 is described in more detail below. The
electric vehicle 10 is a two wheeler scooter including a front wheel 82 and rear wheel
11
84. Rear wheel 84 is provided with a swing arm suspension system described further
below and a shock absorber 94 provided on the swing arm side of the vehicle 10.
Scooter 10 is shown mounted on a stand 176 of conventional form.
[046] The driver steers electric vehicle 10 through handlebar 15 which includes brakes
and horn 15A. The driver is protected by front panel or guard 160 and front mudguard
170 and may comfortably place feet on a floor space 25 created on the floor board 71.
[047] Electric vehicle 10 has an electric motor and transmission system, forming an
integrated motor-transmission assembly 208, powered by an electric battery module 24
comprising a single battery as shown in Figs. 1, 2, 4, 5 and 6. Electric battery module
24 is positioned to the rear of the vehicle 10 above the electric motor and transmission
system 208, a position which provides a convenient position for routing the wire
harness.
[048] According to preferred embodiment, the electric motor has a rating of 7kW to 10
kW (though this rating is dictated by application) and is controlled by motor control unit
(MCU) 100. Batteries 24 are of conventional design each with 48 volt rating preferably
connected in parallel so deliverable voltage is 48 volts.
[049] Scooter 10 includes a frame 11 as mentioned above and this frame structure,
which supports the electric battery module 24 and the motor-transmission assembly 208
along with further vehicle components. Frame 11, and in particular its rear tube 13
comprising battery protective frame structure, is now described in further detail.
[050] The rear tubes 13 are each connected to a downward and rearward extending
head tube 12A and extend towards rear side of vehicle. A forward portion 13A of rear
tube 13 comprises a pair of horizontally extending tubes 13A. The rear portion of each
of rear tubes 13B extends upwardly in the rearward direction of scooter 10 terminating
in a relatively short near horizontal position with the rear tubes 13B converging towards
each other and being connected with a cross member 132.
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[051] Key functions for the rear frame tube 13 are to support the electric battery
module 24 and the other associated components. The following description shows how
these objects are achieved. Rear frame tubes 13B are connected by three cross
members 131, 133 and 134 as shown in Figs. 2 to 5.
[052] A bottom cross member 133 is connected to the rear tubes 13B proximate their
bottom ends. Bottom cross member 133 has a portion in the form of a horizontal
platform 133A on which battery module 24 can be easily supported. The vertical plate
portion 133C of the cross member 133 prevents forward movement of the battery
module 24.
[053] A second U shaped front cross member 131 also connects the rear tubes 13B
toward their mid-section such that when battery module 24 is secured in position, as
described further below, cross-member 131 will restrict opportunities for removal,
especially by theft, as well as placing a restriction on vertical movement of the battery
module 24.
[054] A rear connecting member 134 connects rear tubes 13B, of vehicle frame
extending in a downward direction and is connected with a rear mounting bracket 135
which also enables connection to an upper surface of the battery module 24. According
to one of the embodiment, the rear mounting bracket is fixed to the protective frame
structure (23) using side brackets 135a on both the side of battery module 24. The side
brackets (135a) is fixed to the cross member of protective frame (23) using additional
brackets (130) as illustrated in Fig. 4(a). Once the battery 24 is mounted in the
protective frame 23 it is locked in a position from rear side by clamping the rear
mounting bracket 135 to the side brackets (135a) using nut and bolt 139c. The battery
24 is provided with at least one groove in which a bolt 139b is installed. The bolt 139c is
further clamped to the side bracket (135a). The groove may be used as guiding means
for removing and adjusting the battery 24 during swapping or changing purpose. The
disposition of the cross members 131, 133 and 134 is selected to provide sufficient
volume to accommodate the battery module 24 and will depend on the rating and
dimensions of the battery module 24.
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[055] The rear frame portion 13 and the cross members 131, 133,134 are also
configured to leave a rear opening 137 through which the battery module 24 can be
located. Battery module 24 requires to be securely connected to the rear frame portion
13 and a number of locking means, in the form of nut and bolt fasteners, are used for
this purpose. At the rear end, the battery module 24 is bolted to rear mounting bracket
135. At the forward end, as most conveniently shown in Fig. 4, the battery module 24 is
connected to first forward cross member 133C by a connector including bolt 126, which
extends the height of the battery module 24 and nut 125. To provide further security, a
locking plate 124 extends from the rear of the battery module 24 where it is connected
to rear mounting bracket 135 to the front of the battery module 24. At this location, the
locking plate 124 is connected to the bolt 126 by nut 125. The battery 24 is securely
mounted in the protective frame 23 with the help of locking means therefore; no
separate battery box is required for mounting the battery module 24 securely thereby
not compromising the storage space provided in the storage box 105.
[056] Vibration isolating elements, such as damper 133B (shown in Fig. 3), are placed
between the battery module 24 and the frame 11 to reduce vibrations from battery
module 24 being transmitted to the vehicle frame 11.
[057] The head tube 12A of the vehicle frame 11 is further provided with a cross
member 151 separately fixed to the head tubes 12A. A pair of rearwardly extending
longitudinal members 150 are connected to the cross member 151. Longitudinal
members 150 extend substantially horizontal and parallel to the horizontal portion 13A
of each of the two rear tubes 13. The horizontal longitudinal members and horizontal
portions 13A of the rear tubes 13B allow mounting of a pair of foot panels 71 and 73. A
foot panel 71 is mounted on top of the longitudinal members 150 while a further foot
panel 73 is mounted on the bottom of the frame members 150 as shown in Fig. 7. The
respective sides of the foot panels 71 and 73 are covered by side members,
conveniently creating a hollow space 74 between the two foot panels 71 and 73 which
space 74 is advantageously utilized for various purposes (as part of the cooling system
and for accommodating an auxiliary battery) as described below. Fig. 6 shows greater
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detail of the front panel 160 and a foot supporting portion 71 which includes a cut-out
portion for accommodating the rear frame portion 13 and the battery module 24
amongst other vehicle components.
[058] . Electric battery module 24 includes a protective frame structure 23. The battery
module 24 is mounted such that it does not extend beyond the dimensions of storage
box 105 when viewed from side of the vehicle as shown in Fig. 12. This ensure that the
floor space 25 and storage space of storage box 105 are not compromised. The storage
box 105 is not directly rested on the battery surface or on the protective frame structure
23 thereby, prevent any damage to the battery module 24 from the weight of luggage
placed in the storage box 105.
[059] During operation (charging/discharging), battery temperature increases. In order
to get the maximum efficiency of the battery module 24 and to prolong battery life, the
battery module 24 is maintained at a desired temperature. Ideally, battery operation is
stopped if battery temperature exceeds a pre-determined limit. Cooling is often required
and scooter 10 includes an air cooling system, specifically a ram air cooling system.
[060] As shown in Fig. 8, front body panel 160 includes a number of vents 162 and 164
so that ram air (i.e. the air flow through the vehicle during forward motion) flows over the
battery 24 for cooling purposes.
[061] The front body panel 160 accommodates a cooling air duct communicating with
the vents and desirably the above described space between the floor panels. Ram air
entering through the vents then flows through the duct and into the hollow space 74
between the floor panels 71 and 73 to be guided by air guiding means towards the
battery 24 for cooling purposes, the components forming an air cooling system. The air
guiding means is conveniently provided on the bottom floor panel. The air cooling
system may further include air passage(s) directing air towards a targeted area of the
battery surface to achieve effective cooling.
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[062] Operation of electric motor (not shown) is controlled by Motor Control Unit (MCU)
100. The current supply to electric motor has to be AC while the current supplied from
battery 24 is DC; the conversion from DC to AC is also controlled by MCU 100.
[063] MCU 100 determines the amount of torque to be produced by electric motor
based on various vehicle operating conditions along with the correspondent amount of
current/ voltage to be supplied to electric motor. MCU 100 comprises a basic map of the
amount of power to be supplied to the electric motor to generate required torque as a
function of selected vehicle conditions, for example present vehicle speed and
accelerator pedal or grip position. Therefore, if scooter 10 is accelerated or decelerated,
its torque requirement changes; similarly, if during various running conditions, the total
load on scooter 10 changes, this reduces or increases the vehicle speed which changes
the torque requirement. Based on vehicle speed and accelerator position, the required
torque is determined from the basic map and accordingly the required electric power
(current/voltage) is supplied to electric motor to generate the required torque under the
control of MCU 100.
[064] As shown in Figs. 1 and 9 to 13, the MCU 100 is positioned near battery 24 on
the rear side of vehicle 10 which results in reduced wiring harness 102 length in
contrast to placing the MCU 100 on the front side of scooter 10. Placing the MCU 100
below the floor panels 71 and 73 would increase chance of damage due to external
impacts. As shown, the MCU 100 is mounted on the left hand side of scooter 10. MCU
100 is fixed to the vehicle frame using mounting brackets.
[065] Scooter 10 comprises a range of low voltage electric components such as
headlamp, tail lamp, horns, Indicators and so on. In certain scenarios, these
components need to be operated even if the vehicle 10 is not running, though the power
requirement of these components is comparatively less than for the electric motor.
Although, these components can run directly on the supply of the main battery 24,
supplying these components with power from an alternative low voltage power source
such as auxiliary battery, which is lower capacity/rating as compared to main battery 24
is advantageous. For example, using direct current from the main battery 24 to power
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the low voltage components can lead to safety issues. The auxiliary battery can also be
used as a safety lock for vehicle 10 before starting the main battery 24. Conveniently,
the auxiliary battery has 12V capacity and is very small in size as compared to the main
battery 24.
[066] The auxiliary battery is placed within the space created between the floor panels
71 and 73. The top floor panel 71 is provided with a small box type opening for
accommodating the auxiliary battery. A cover 72 is fitted on top of the opening to
secure the auxiliary battery into position. This convenient location for access for
servicing also helps in easy routing of the vehicle wiring harness.
[067] A DC-DC convertor 28 is also mounted on the MCU 100 as shown in Fig. 10
using suitable mounting brackets. This helps in reducing the length of the wiring
harness. The function of the DC-DC convertor 28 is to charge the auxiliary battery by
taking current from the main battery 24. Since the auxiliary battery operates at much
lower voltage than battery 24, a direct current from the 48 volt main battery 24 cannot
directly be used to charge the auxiliary battery. DC-DC converter 28 steps down the
voltage so that power from the main battery 24 can be used to charge auxiliary battery.
According to another embodiment, the DC-DC converter 28 is packaged towards rear
side of vehicle at ends of the rear tubes 13 as shown in Fig. 14(a) and 14(b). The DCDC
convertor may be suitably covered by vehicle covering members.
[068] Connectivity box 200, shown in Fig. 2, is the core of the electronic system used
in vehicle 10 including communications functionality and other electronic and controlling
components. All the components in vehicle 10 are connected over a common CAN type
network where data from various components can be transmitted to respective
controlling units in digital form. For example battery 24 can share the information such
as its state of charge or state of health to the connectivity box 200 over CAN network.
The connectivity box 200 has a storage medium for storing data received from various
components such as battery information, vehicle speed, distance travelled, driving
pattern etc. The stored information may be transmitted directly to a mobile device or a
remote server/ cloud for processing as required, for example as described below.
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Control software updates can be transferred in the same way. The connectivity box 200
has suitable communication means such as Bluetooth, internet connectivity such as Wi-
Fi or a telecommunication network capability using GSM SIM or all of these. The
connectivity box 200 has also a GPS transmitter which helps in identifying the vehicle
location. The data transmitted to the cloud or mobile device can be useful in various
means such as identifying the vehicle location, understanding the driving pattern, error
logs, identifying need to charge or change the battery etc. This data may also be useful
from vehicle servicing or maintenance perspective and service alerts can be issued as
required on a periodic basis.
[069] Connectivity box 200 is located on the front side of scooter 10, specifically being
mounted on head pipe 12, which is a position with a sufficient distance from the
batteries 24, auxiliary battery to avoid magnetic interference on the electronic
components contained in the connectivity box 200. Taking such considerations,
including available space into account, the connectivity box 200 is best placed on the
front side of vehicle 10 which also helps in easy wiring harness routing.
[070] Scooter 10 also comprises an accident sensor (not shown) which senses the
vehicle position and identifies the accident scenario. If any such scenario is detected
then an alarm signal is sent to a mobile and also to a cloud with vehicle location
information so that assistance can be given.
[071] The charger unit 29 is used for charging battery module 24. It receives AC
current from an external power supply, converts the supply to DC and supplies the
power with specific current voltage to battery module 24 for charging the batteries. The
amount of current and voltage as well as duration of current to be supplied to battery
module 24 for charging purposes may fixed using a controller included within a battery
management system. The input is given to a charger through cable 110 which
thereafter controls the power supplied to battery module 24 according to instructions
received from the battery management system. The control parameters for the battery
charger 29 may vary based on the size and number of batteries used. The weight of the
charger 29 is also considerable. In order to achieve better balance while driving, the
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charger 29 is accommodated on one side of the vehicle preferably on the opposite side
to the ECU 100 location. This positioning helps in balancing the weight. Since the
charger 29 is fixed on the vehicle 10 itself, its position needs to be safe and secured
from external impacts and also from theft. To this end, charger 29 is firmly and securely
mounted on the vehicle chassis 11 and the rear tubes. The charger 29 is preferably
mounted on the opposite side of MCU (100) in order to better distribute the weight and
achieve better balance. The charger 29 may be mounted to the vehicle frame with the
help of suitable brackets.
[072] The battery 24 can therefore be charged on board the vehicle 10. However, the
battery 24 can also be removed for charging. Scooter 10 is provided with a seat 103 as
shown in Figs. 12 and 14. The seat 103 is hinged at one point allowing opening to
access the luggage compartment 105 and the charging point 129. The positioning of the
battery module 24 within rear frame portion 13 enables the capacity of the luggage
compartment 105 to be maximised for a particular scooter 10 and battery module 24
rating and dimensions.
[073] Charging point 129 is provided inside seat 103 as shown in Fig. 13. For charging
of battery 24, seat 103 is opened, the charger cable 110 is plugged into the charging
point 129 and a power source and charging is started. Keeping seat 103 open for the
duration of charging may not be preferred since the charger 110 needs to be secured
from an anti-theft perspective as well as from environmental effects. Therefore,
provision is made such that, during charging, the seat 103 can be closed and locked so
that the charger 110 remains secured inside the luggage compartment 105 and cannot
be removed without opening seat 103.
[074] Referring to Figs. 9 to 14, scooter 10 is provided with a rear mono-suspension
i.e. only one shock absorber 94 is used to provide rear suspension to reduce cost.
Shock absorber 94, which may be of SNS type as described in the Applicant’s Indian
Patent No. 695/MUM/2005, the contents of which are hereby incorporated herein by
reference, is located at the rear of scooter 10 rather than at its centre. A front shock
absorber is also provided.
19
[075] The shock absorber 94 is connected on the motor-transmission 20/80 side of
scooter 10 since load is greater on that side. One end of shock absorber 94 is
connected to the casing 208C of the motor-transmission assembly 208 by bolt while the
other end is connected to rear frame portion 13 by a mounting bracket 13C. A forward
end of the Motor- Transmission Assembly is mounted at a bracket 198C which is
welded on the protective frame structure 23 while the rear end of the motortransmission
assembly 208 is mounted at rear axle of the rear wheel 84. Motortransmission
assembly 208 is conveniently described in the Applicant’s co-pending
Indian Patent Application No. 201821047186 filed on 13th December’ 2019, the
contents of which are hereby incorporated herein by reference.
[076] The fig. 15 shows a schematic rear view of the vehicle according to the present
invention with a charging cable 110 coming out from the seat 103 in the closed position.
The motor-transmission assembly 208 is illustrated.
[077] Modifications and variations to the electric vehicle described in the present
specification may be apparent to skilled readers of this disclosure. Such modifications
and variations are deemed within the scope of the present invention. ,CLAIMS:We Claim:
1. A frame for an electric vehicle (10) comprising:
a head pipe (12) and at least two rear tubes (13) extending rearwardly from
the head pipe (12);
an electric battery module (24) used as a power source for powering the
electric vehicle comprising at least one battery located below rear portion (13B) of
said rear tubes (13);
a protective frame structure (23) for securely mounting said battery module
(24); wherein said protective frame structure (23) is fixed to said rear tubes (13) of
said frame and provided substantially centrally and downwardly of said vehicle and
said battery module (24) is locked to the protective frame structure (23) from front
and rear side of the battery module (24).
2. A frame for an electric vehicle (10) as claimed in claim 1 wherein; the protective
frame structure (23) includes plurality of cross members connected to the rear tubes
(13) to create a space for mounting and supporting the electric battery module (24).
3. A frame for an electric vehicle (10) as claimed in claim 2 wherein; the cross
member (131, 133, 134) of said protective frame structure is provided with locking
means to securely fix the electric battery module (24) from front and rear side to
minimise vibrations and to prevent from theft.
4. A frame for an electric vehicle (10) as claimed in claim 2 wherein; the locking
means provided on the rear side of the battery module (24) including a rear mounting
bracket (135) used to lock the battery position from rear side by clamping said rear
mounting bracket (135) to the side brackets (135a) from both sides of the battery
module (24) and further locked by clamping the battery module (24) to the side
brackets (135a) using a bolt (139b) provided in a groove (24a) on the battery module
(24); said side brackets (135a) are fixed to protective frame structure (23).
5. A frame for an electric vehicle (10) as claimed in claim 2 wherein; the cross
member (131, 133, 134) is provided with a guiding means for conveniently mounting
and removing the electric battery module (24) from the protective frame structure (23)
for charging/ swapping function.
6. A frame for an electric vehicle 10 as claimed in claim 2 wherein; the electric
battery module (24) is removed from either the front side, back side or from left or right
side of the vehicle (10) for charging or swapping purposes.
7. A frame for an electric vehicle 10 as claimed in claim 2 wherein; the electric
battery module (24) is mounted either horizontally or vertically inside protective frame
structure (23).
8. A frame for an electric vehicle 10 as claimed in claim 2 wherein; the cross
members (131, 133, 134) are provided with vibration isolating elements (133B) on
which the electric battery module (24) is mounted to reduce vibrations being
transmitted to the electric battery module (24).
9. A frame for an electric vehicle (10) as claimed in claim 2 wherein; the electric
battery module (24) is located substantially centrally along the width of the vehicle (10)
and substantially centrally along the length of the vehicle (10).
10. A frame for an electric vehicle (10) as claimed in claim 2 wherein; the plurality
of cross members (131, 133, 134) include front, rear and bottom cross member(s)
connecting the rear tubes (13) wherein; the front cross member (131) connects the
rear tubes (13) towards the front of the vehicle (10); the rear cross member (134)
connecting the rear tubes (13) towards the rear of the vehicle and the bottom cross
member (133) is connected to the rear cross member (134) and rear tubes (13) in
substantially horizontal direction to create a platform (133A) on which the battery
module (24) securely resides.
11. A frame for an electric vehicle 10 as claimed in claim 10 wherein; the front cross
member (131) extends substantially horizontally over a top surface of the battery
module (24) to restrict any vertical movement of the electric battery module (24); the
rear cross member (134) is provided with a rear mounting bracket (135) to further
restrict movement of electric battery module (24) and the bottom cross member (133)
is provided with a first forward cross member (133C) used to restrict forward
movement of battery module (24) using a bolt (126) which extends till the height of
battery and connects the rear mounting bracket (135) through a locking plate (124).
12. A frame for an electric vehicle (10) as claimed in any one of the claim above
wherein; the electric battery module (24) is mounted in the protective frame structure
23 such that a storage space is created above the electric battery module (24) for
mounting a storage box 105 used for storage of articles such that the battery module
(24) does not extend forwardly beyond the dimensions of storage box 105 when
viewed from side of the vehicle.
13. A frame for an electric vehicle (10) as claimed in any one of the claim above
wherein; the rear tubes (13) are provided with at least two longitudinal frame members
(150) substantially horizontal and parallel to the horizontal portion (13A) of each of the
two rear tubes 13 wherein; said longitudinal frame members (150) allow mounting of
foot panels (71, 73) such that one foot panel (71) is mounted on top of the longitudinal
frame members (150) while another foot panel (73) is mounted on the bottom of the
longitudinal frame members (150) and the respective sides of the two foot panels are
covered with side members, thereby creating a hollow space (74) between the two
foot panels which is utilized for various purposes including battery cooling and
accommodating other components such as auxiliary battery, wiring harness, motor
control unit (MCU 100).
14. A frame for an electric vehicle (10) as claimed in claim 13 wherein; the electric
battery module (24) is provided with a ram air cooling means wherein; the ram air is
allowed to flow from front side of the vehicle through one or more vents (162, 164)
provided in a front body panel(s) (160) of the vehicle and through the hallow space
(74) created between two floor panels (71, 73) to be guided by air guiding means
towards the battery module 24 for cooling purpose.
15. A frame for an electric vehicle (10) as claimed in any one of the claim above
wherein; the rear tube (13) is provided with mounting means for mounting a motor
control unit (MCU 100) such that the MCU (100) is mounted proximate to the electric
battery module (24) on the left hand side of the vehicle (10).
16. A frame for an electric vehicle (10) as claimed in claim 15 wherein; the MCU
(100) is configured to control the amount of torque to be produced by an electric motor
by controlling the amount of current/ voltage supplied based on at least one vehicle
operating condition wherein; the amount of current/ voltage to be supplied to the
electric motor is decided based on a basic map of the amount of power to be supplied
to the electric motor to generate required torque as a function of selected vehicle
conditions including present vehicle speed and/ or accelerator pedal or grip position.
17. A frame for an electric vehicle (10) as claimed in any one of the claim above
wherein; the rear tubes (13) are provided with a mounting provision for mounting a
DC-DC converter (28) at the end of the rear tubes (13).
18. A frame for an electric vehicle 10 as claimed in any one of the claim above
wherein; the head pipe (12) is provided with mounting provision for mounting a
connectivity box (200) on the front side of the vehicle (10) wherein; the connectivity
box (200) is configured to receive the information including battery information, vehicle
speed, distance travelled, driving pattern, vehicle location, accident information and
further configured to store and share the information with external device over suitable
communication network including Wi-Fi, Bluetooth, Internet or telecommunication
network.
19. A frame for an electric vehicle (10) as claimed in any one of the claim above
wherein; the rear tube (13) is provided with a mounting provision for mounting a
charger unit (29) used for charging battery module (24) on right hand side of the
vehicle.
20. A frame for an electric vehicle as claimed in claim 1 wherein; the electric battery
module (24) is charged on board the vehicle (10) using a charging cable (110) to
connect the charger (29) to external supply through a charging point (129) wherein;
the charging point (129) is provided on the rear end of the vehicle (10) below seat
(103) such that the charging cable 110 remains plugged and charges the battery
module (24) even if the seat (103) is closed/ locked.
21. A frame for an electric vehicle 10 as claimed in claim 1 wherein; the electric
battery module (24) is in connection with a motor-transmission assembly (208)
wherein; said motor-transmission assembly is mounted such that a forward end of the
motor- transmission assembly (208) is fixed at a bracket (198C) which is welded on
the protective frame structure (23) while the rear end of the motor- transmission
assembly (208) is mounted at a rear axle of a rear wheel (84).
22. A frame for an electric vehicle (10) as claimed in claim 21 wherein; the motortransmission
assembly (208) is provided with a casing (208C) wherein; the casing
(208C) itself is acting as a swing arm.