BATTERY PACK ASSEMBLY STRUCTURE FOR AN ELECTRIC VEfflCLE
FIELD OF INVENTION

[0001] The present invention relates to a battery assembly structure of an electric vehicle and more particularly to a structure for facilitating easy charging and replacement of individual batteries in the battery assembly structure of a three-wheeled electric vehicle.

BACKGROUND OF INVENTION

[0002] Rapidly depleting oil reserves, environmental degradation due to global warming and air pollution are leading to growing interest in electric vehicles. Electric Vehicles commonly have at least one electric motor driving the wheels of the vehicle and the motor receives electrical energy from battery packs or fuel cells. An electronic control unit receives signals from various sensors comprising throttle position sensor and motor - rotor position sensor and controls the motor suitably to meet user-driving requirements.

[0003] A major drawback with battery operated electric vehicle when compared with fossil fuel based internal combustion engine powered vehicle is the limited driving range and long recharging time. Current battery technology limits the driving range of a conventional electric vehicle and further increase in number of batteries will lead to increased weight and size of the vehicle. While refueling is possible within a minute in case of vehicles with fossil fuel based internal combustion engine, it takes hours for batteries to be recharged and battery manufacturers generally recommend overnight charging. Indian granted patent IN224219 discloses an electrically operated automotive vehicle wherein a battery pack having co-located and interconnected batteries, is slidably connected with the vehicle chassis and a manually operable lever clamps the battery pack to the vehicle chassis.

Upon recognition of depleted state of charge of the battery pack, the user can drive the vehicle to a charging station where a fully charged battery pack is stationed. The user can operate the lever to disengage the battery pack, disconnect an electrical connection and slide the battery pack out of the vehicle. Ancillary lifting equipment is required to lift the discharged battery pack and replace with fully charged battery pack. Although the system enables the user to extend the vehicle driving range in a given day, the requirement of ancillary lifting equipment makes replacement tedious. It will further be beneficial if individual battery state of charge (SOC) could be sensed and only batteries with low SOC are replaced because interconnected batteries generally discharge unequally and it will be quicker to replace a few batteries rather than the entire battery pack.

SUMMARY OF THE INVENTION

[0004] A battery pack assembly structure for an electric vehicle
comprising a plurality of battery trays fitted on carriage columns, which in turn is fitted to the vehicle chassis. The individual batteries can be slid into and removed from the said battery trays and separate connectors are provided in each battery for charging and discharging through electrically conducting bars and mating connectors fitted on a panel board. SOC of each battery is selectively indicated visually to enable the user to identify batteries that need to be replaced. Positive locking means is also provided in each battery for securing the battery with corresponding battery tray.

[0005] Individual batteries with low SOC can be unlocked from the
battery trays of the said vehicle and can be replaced with fully charged batteries available within the battery trays of the charging location's battery pack assembly structure.

BRIEF DESCRIPTION OF DRAWINGS

[0006] Figure 1 illustrates a three-wheeled vehicle chassis fitted with the battery pack assembly structure.

[0007] Figure 2 shows a section of the battery pack assembly structure with partially assembled batteries.

[0008] Figure 3 illustrates a section of the battery pack assembly structure including batteries.

[0009] Figure 4 shows a split view of a section of the battery pack assembly structure.

[00010] Figure 5 shows an individual battery, which can be connected with the battery pack assembly structure.

[00011] Figure 6 shows the battery pack assembly structure located beneath a driver seat of the vehicle.

[00012] Figures7-to-ll illustrate different embodiments of assembly battery trays beneath a driver seat.

[00013] Figures 12 and 13 illustrate location of battery pack assembly structure within a rear cabin of the vehicle.

DETAILED DESCRIPTION OF THE INVENTION

[00014] The present invention of a battery pack assembly structure for an electric vehicle will be described for a preferred embodiment of an electric three-wheeled vehicle. However the invention is applicable for other vehicles like two-wheeled and four-wheeled electric vehicles also.

[00015] Referring to Fig 1, an electric three-wheeled vehicle chassis 10 comprises hollow rectangular cross members with which various parts are connected. A floorboard 20 allows a front cowl 30 to be fitted at the front of the vehicle and allows a partition wall 40 to separate a driver seating area from passenger seating area. A front wheel is connected with a front trailing arm, which in turn has a pivot joint with a steering column 50. There is a front suspension support between the trailing arm and the steering column. A handle bar is connected with the steering column 50 for changing the direction of travel of the vehicle. There is a dashboard connected with the front cowl and comprising the various switches and indicators for helping the driver in starting and driving the vehicle in traffic conditions. A mudguard 60 is connected with the front cowl 30 for covering the front wheel. A battery pack assembly structure 70 comprising battery trays 80, carriage columns 90 and panel board 100 is connected with the floorboard 20 by means of fasteners. Batteries 110 are slidably inserted into the battery trays 80 and securely locked in place. The battery 1 trays 80 and carriage columns 90 are made using mild steel sheets.

[00016] Referring to Fig 2 and Fig 3, the battery pack assembly structure 70 is made up of sections 120 comprising batteries 110 inserted into battery trays 80 and electrically connected with mating connectors 130 provided on the panel board 100. A locking pin 140 provided in each battery 110 can be engaged or disengaged by means of a master key in order to lock or release each battery 110 from the battery pack assembly structure 70. When batteries 110 are inserted into the battery trays 80 and locked by means of the master key, the locking pin 140 protrudes out of the battery case and slides into holes 150 provided in the battery pack assembly structure 70.

[00017] Referring to Fig 4 and Fig 5, the panel board 100 is made of an insulating material like Bakelite and has connectors 130 fitted for mating with corresponding terminals in battery 110. The connectors 130 are a pairs of connectors for mating the corresponding charging and discharging terminals of the plurality of batteries 110. Conducting bus bars 170 interconnect the batteries 110 in series or parallel configuration depending on voltage and amperage requirement. Multiple sections 120 can be connected in back-to-back configuration to interconnect a large number of batteries in a small space. Each battery 110 has two connectors - charging connector 180 and discharging connector 190 for providing separate path for charging and discharging respectively and corresponding mating connectors 160 in the panel board 100 allow the bus bars 170 to interconnect the charging and discharging terminals of batteries 110 in a desired configuration. The preferred embodiment has batteries 110 interconnected for charging in series and discharging in parallel. Each battery 110 also has a foldable handle for sliding the battery out of the corresponding battery tray 80 and for hand carrying the battery to the charging station. The preferred embodiment uses Lithium Ion battery cells within each battery 110 and each battery 110 has an electronic battery management system to control the battery charging and discharging parameters. Each battery 110 also has provision for selective visual indication of the SOC on the battery casing by means of operable switches provided on the surface of the casing. In the preferred embodiment, green color indication represents a healthy battery and red color indicates low SOC condition.

[00018] Referring to Fig 6, the battery pack assembly structure 70 is located beneath a driver seat 200 so that better traction can be achieved in all wheels and can result in better hill climbing ability, acceleration and stability characteristics. The master key used for unlocking batteries 110 from the battery trays 80 can also be used for unlocking a battery pack assembly enclosure, which prevents water, dust and foreign particles from interfering with the battery pack assembly structure 70.

[00019] Referring to figures 7 - 11, different embodiments of assembling battery trays 80 in the battery pack assembly structure 70 are illustrated. Depending on the rating of each battery 110, number of batteries required for the vehicle and space available, appropriate battery pack assembly structure can be chosen. Referring to Fig 12 and 13, further embodiments illustrate the battery pack assembly structure fitted at the rear cabin of the vehicle behind the passenger seating area. The batteries are equipped to be fitted in both horizontal and vertical direction.

[00020] By providing separate charging and discharging paths in the battery pack assembly structure 70, on-board charging and regenerative braking can also be enabled.

[00021] The electrical connecting terminals in the panel board 100 are also electrically connected with an instrument cluster fitted on the dashboard of the vehicle for sensing the SOC of the on-board batteries 100. If the user detects that the SOC of certain batteries 100 has decreased below a predefined threshold recommended by the manufacturer, the user can selectively check the batter}' SOC that is visually indicated on the battery casing after unlocking the battery pack assembly enclosure. Thereafter, the user can unlock the depleted battery 100 from the battery tray 80 using the master key and slide the battery out of the battery tray 80. The user can hand carry the battery 110 to the charging station where a replica of the battery pack assembly structure 70 is located for charging batteries by means of a battery charger. The user can unlock and slide out a fully charged battery 110 from the battery pack assembly structure 70 located in the charging station and replace with the depleted battery 110 for charging. The user can hand carry the fully charged battery 110, insert into battery tray 80 in the vehicle and lock the battery 110 in place to further continue driving the vehicle without affecting performance.

[00022] The battery pack assembly structure 70 could also be fitted beneath the passenger seating area. The assembly structure 70 could also be used with hybrid vehicles wherein in addition to the batteries 110, an internal combustion engine or fuel cell is also generating energy required for driving the wheels. Other modifications might become obvious to a person skilled in the art based on the description and drawings provided without departing from the spirit and scope of the invention.

We claim:

1. A battery storing structure (70) for an electric vehicle, the structure comprising:
a plurality of carriage columns (90), the said carriage columns being mounted to a vehicle chassis (20); plurality of batteries (110) wherein the said batteries have separate receptacles for charging (180) and discharging (190); a plurality of battery trays (80), laid horizontally at various vertical levels on the said carriage columns (90), wherein the said battery trays (80) are equipped with a slide-in means (140,150) for sliding individual batteries; the said battery trays and the battery outer body being provided with a locking mechanism (140,150) for locking the individual batteries in the said individual battery trays; a panel board (100) , wherein the said panel board (100) comprises of a plurality of bus bars (170); the said bus bars (170) being connected to the charging (180) and discharging (190) terminals of the said batteries in a pre determined pattern to obtain various serial and parallel combinations for charging and discharging of the said batteries (110).

2. The bus bars (170) as claimed in claiml have two separate receptacles corresponding to every (180,190) battery, one each for charging and discharging.

3. The battery storing structure (70) as claimed in claim 1 is located on the opposite side of the motor with respect to the longitudinal axis of the vehicle

4. The battery storing structure (70) as claimed in Claim 1 is positioned below the driver's seat.

5. The battery storing structure (70) as claimed in Claim 1 is positioned below in the rear cabin of the vehicle behind the passenger seating area.

6. The battery storing structure (70) as claimed in Claim 1 is positioned in the back and below the cabin space.

7. The battery trays (80) as claimed in Claim 1 are tilted horizontally to facilitate the sliding of batteries in the said battery trays (80).

8. In the panel board (100) as claimed in Claim 1 arrangement is made for
both onboard and off board charging.

9. The panel board (100) as claimed in Claim 1 has mating receptacles for
charging and discharging on both the sides and the said panel board is
tilted at an angle to the horizontal to accommodate inclined batteries
(110).