Patent Publication Number: US-2003231000-A1

Title: Method and apparatus for charging electric vehicles

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates generally to electrical vehicles or automobiles. More particularly, the present invention relates to a method and apparatus for recharging batteries in electric vehicles.  
       [0003] 2. Description of the Related Art  
       [0004] An electric vehicle (EV) is a car, truck or van that uses grid electricity to power the vehicle instead of gasoline. Grid electricity is relatively inexpensive compared to most forms of fossil fuel (including oil) and may be generated from renewable energy sources such solar and wind energy. Although it has been a goal of most industrialized countries to reduce their dependencies on oil and reduce air pollution in the process, only in the recent few years has technology enabled the manufacturing of electric vehicles become practical.  
       [0005] In addition to purely battery powered electric vehicles (BEV), there are several other vehicle types that use electric power. For example, a hybrid electric vehicle (HEV) has electric components, but uses a fuel source instead of grid electricity to power the vehicle. A fuel cell vehicle (FCV) uses fuel cell instead of grid electricity to power the vehicle. Electric vehicles, whether powered by batteries, fuel cells, or gasoline hybrids, include an energy source and electronics capable of generating electricity. When connections are added to allow electricity to flow from cars to power lines, it is termed vehicle to grid (V2G) power.  
       [0006] Currently, battery electric vehicles provide for the greatest reduction in air pollution causing emissions. Unfortunately, the cost-effectiveness of a BEV is lower than either the cost-effectiveness of a HEV or FCV. In addition, operating a BEV also requires a great deal more maintenance than other types of vehicles. The standard amount of time required to refuel a BEV is about six to eight hours. In addition, most BEVs have a very limited range, even running on a full charge. For example, the EV1, manufactured by General Motors has a range of only about 88 kilometers to about 152 kilometers. Even with an additional battery pack, the EV1&#39;s range only increases about 30 to 40 kilometers.  
       [0007] In view of the foregoing, it is desirable to have a method and apparatus for charging EVs during vehicle operation. It is also desirable to charge an EV while the vehicle is being driven to increase the operating range of the vehicle as well as reduce recharging time when the vehicle is not being used.  
       SUMMARY OF THE INVENTION  
       [0008] The present invention fills these needs by providing a method and apparatus for charging an electric automobile. It should be appreciated that the present invention can be implemented in numerous ways, including as a process, an apparatus, a system, a device or a method. Several inventive embodiments of the present invention are described below.  
       [0009] In one embodiment of the present invention, a battery charger for an electrical vehicle is provided. The battery charger includes an air scoop to receive a flow of air. A turbine then receives the flow of air from the air scoop during vehicular operation. The air scoop preferably directs the flow of air to one side of the turbine causing the turbine to rotate either in clockwise or counter clockwise fashion. The turbine preferably includes air holes to allow the release of air from the battery-charging system. A generator coupled to the turbine generates electricity when the turbine rotates. The electricity generated by the generator charges a battery coupled to the generator. The battery-charging system may also include a relay to allow the turbine to rotate only when the speed of the vehicle is high enough to generate an adequate air flow for the system.  
       [0010] In another embodiment of the present invention, a method for charging a battery in an electric vehicle is provided. The method begins by providing a flow of air to generate a force in a turbine coupled to a generator. The force generated rotates both the turbine and the generator. Electricity is generated by the said generator and is used to charge the battery. The air is preferably directed to one side of the turbine to ensure that the turbine rotates either in clockwise or counter clockwise fashion. Air flowing into the turbine is preferably released through a number of air holes formed on the turbine.  
       [0011] In yet another embodiment of the present invention, a battery charger for an electrical vehicle is provided. The battery charger includes an air scoop to receive a flow of air. A turbine then receives the flow of air from the air scoop during vehicular operation. The turbine preferably includes a pair of circular plates are that connected by a central spindle. A plurality of rectangular plates is coupled to the pair of circular places, and positioned radially along said pair of circular plates to preferably form air channels to receive the flow of air. The flow of air causes the turbine to rotate. A generator coupled to the turbine generates electricity when the turbine rotates. The electricity generated by the generator charges a battery coupled to the generator.  
       [0012] Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0013] The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements.  
     [0014]FIG. 1 illustrates a system for charging a battery in accordance with one embodiment of the present invention.  
     [0015]FIG. 2 a  illustrates a cross-sectional view of a battery-charging system fitted under the bonnet of an EV in accordance with one embodiment of the present invention.  
     [0016]FIG. 2 b  illustrates a top view of an upper strut bar in accordance with one embodiment of the present invention.  
     [0017]FIG. 2 c  illustrates a top view of a lower strut bar in accordance with one embodiment of the present invention.  
     [0018]FIG. 3 illustrates a schematic of a system for charging a battery in accordance with another embodiment of the present invention.  
     [0019]FIG. 4 illustrates a cross-sectional view of a battery-charging system fitted on the roof of an EV in accordance with another embodiment of the present invention.  
     [0020]FIG. 5 illustrates a perspective view of an EV in accordance with a further embodiment of the present invention.  
     [0021]FIG. 6 illustrates a method of charging a battery in accordance with one embodiment of the present invention.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0022] A method and apparatus for charging an electric automobile is provided. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be understood, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention.  
     [0023]FIG. 1 illustrates a battery-charging system  10  in accordance with one embodiment of the present invention. Battery-charging system  10  comprises a grill  12  connected to an air scoop  14 , which receives a flow of air. The force generated by the flow of air is then used to rotate a wind turbine  16 , which is coupled to a generator  18 , so as to generate a current to recharge a battery  20 . Battery-charging system  10  is preferably located under the hood or bonnet of an EV.  
     [0024] Grill  12  acts as an air filter, preventing small object, such as rocks, from entering battery-charging system  10 . Grill  12  therefore allows air to enter battery-charging system  10 , while preventing foreign objects from interfering with the operation of turbine  16 . Driving or operating the EV generates the current or flow of air. The air that enters battery-charging system  10  is then directed by air scoop  14  to one side  22  of wind turbine  16  where it enters an air channel  24 . It will be apparent to a person skilled in the art that side  22  may be to the left or right of wind turbine  16  depending on the type of turbine that is employed.  
     [0025] An entrance  26  of air scoop  14  is preferably in the range of about 80 to about 110 centimeters, so that more air will be captured by the system. However, it should be appreciated that the size of entrance  26  is ultimately dependent upon and limited by the size of the vehicle. For example, a larger vehicle will presumably have more space to house and accommodate a larger air scoop  14  than a smaller vehicle.  
     [0026] Wind turbine  16  comprises two circular plates  28 . A plurality of rectangular plates  30  is located radially between two circular plates  28  around a central spindle  32 . Rectangular plates  30  divide wind turbine  16  into a number of air channels  24 . Pressure exerted on rectangular plates  30  by a force generated by the current of air causes wind turbine  16  to rotate about central spindle  32 . Air is allowed to exit via a plurality of air holes  34  on one or both of circular plates  28  at an end of air channel  24  nearest central spindle  32 . Wind turbine  16  may be constructed of low-density metals or alloys, plastic, carbon fiber, fiberglass or other light and durable materials. It will be apparent to a person skilled in the art that wind turbine  16  is not limited to the design described herein. For example, another possible design for wind turbine  16  is a bladed turbine, with or without a housing.  
     [0027] Central spindle  32  couples wind turbine  16  to generator  18  so that the rotary motion of wind turbine  16  is transmitted to generator  18 , which in turn, generates a current to recharge battery  20 . Examples of batteries that could be charged with this system include a lead acid battery, a lithium-ion battery and a lithium (metal) sulfide battery. The type of battery employed depends on the purpose for which the EV was built, as well as the type of electric motor and the controller used. For instance, an EV built for racing would probably require a battery capable of generating more horsepower in the vehicle leading to better acceleration and a higher top speed.  
     [0028] Generator  18  may be either an alternating or a direct current (DC) motor, preferably one that utilizes a permanent magnet instead of field coils. Because field coils require power, some of the energy produced by wind turbine  16  will be consumed by the field coils instead, resulting in waste of power. Generator  18  may also be an automobile alternator. It is also preferable to have a low-dragging generator, which enables wind turbine  16  to rotate even when the vehicle is moving at low speeds.  
     [0029] Although not depicted in FIG. 1, a relay may be implemented in battery-charging system  10  such that generator  18  begins charging battery  20  only when wind turbine  16  reaches a certain rotary speed. The relay may also be configured such that generator  18  goes offline when battery  20  is fully charged. Battery-charging system  10  may also be placed under the bonnet of an EV as demonstrated by FIGS. 2 a ,  2   b  and  2   c . FIG. 2 a  is a cross-sectional view of battery-charging system  10  placed under the bonnet of an EV, FIG. 2 b  is a top view of an upper strut bar  36  and FIG. 2 c  is a top view of a lower strut bar  38 .  
     [0030] Wind turbine  16  rotates around central spindle  32  and air escapes from wind turbine  16  via plurality of air holes  34 . The upper end of central spindle  32  is connected by a plurality of bolts  40  and a plurality of nuts  42  to upper strut bar  36 . Conversely, the lower end of central spindle  32  is connected by a plurality of bolts  44  and a plurality of nuts  46  to lower strut bar  38 . Central spindle  32  transmits the rotary motion of wind turbine  16  to generator  18  via a belt  48 . The current generated by generator  18  recharges battery  20 . Generator  18  is preferably attached to the chassis of the EV with a plurality of bolts  50  and nuts (not illustrated), however as is well known in the art, there are many acceptable methods of attaching a generator to the chassis of a vehicle.  
     [0031] Each end of central spindle  32  is encased in a cylindrical support  52 . Cylindrical support  52  is filled with lubricant  54 . Lubricant  54  is changed on a regular basis by draining the contents of cylindrical support  52  through outlet  56  and adding fresh lubricant  54  through inlet  58  after approximately every 20,000 kilometers (km) of vehicular operation. Further lubrication of each end of central spindle  32  is achieved by employing a ball bearing system  60 .  
     [0032] Upper strut bar  36  is attached to the chassis of the EV, preferably on top of the front suspension, by a plurality of nuts  62  and bolts (not illustrated). Lower strut bar  38  is attached to the chassis of the EV by a plurality of bolts  64  and nuts (not illustrated). A piece of hard rubber  66  separates lower strut bar  38  from the chassis of the EV and serves as a vibration absorber.  
     [0033]FIG. 3 illustrates a battery-charging system  100  in accordance with another embodiment of the present invention. Battery-charging system  100  comprises a grill  102  connected to an air scoop  104 , which receives a flow of air. A force produced by the flow of air rotates a wind turbine  106 , which is coupled to a generator  108 , which in turn generates a current to recharge a battery  110 . Grill  102  allows air into battery-charging system  100  during vehicular operation. The current of air passes through an entrance  116  of air scoop  104  and is directed to a side  112  of wind turbine  106  where it enters an air channel  114 .  
     [0034] Wind turbine  106  comprises an upper circular plate  118  and a lower circular plate  120 . A plurality of rectangular plates  122  is arranged radially between circular plates  118  and  120  around a central spindle  124 . Rectangular plates  122  divide wind turbine  106  into a number of air channels  114 . A force exerted on rectangular plates  122  by the current of air causes wind turbine  106  to rotate about central spindle  124 . Air is allowed to exit via a plurality of air holes  126  on either of the circular plates  118  and  120 , preferably lower circular plate  120  at an end of air channel  114  located nearest to central spindle  124 .  
     [0035] Lower circular plate  120  includes a plurality of gear teeth  128  around its circumference, which engages a second gear  130  on generator  108 . Although depicted in this embodiment as spur gears, it will be appreciated by a person skilled in the art that other types of gears such as helical gears, bevel gears and worm gears may be employed as well. In a preferred embodiment, gear teeth  128  are of an involute profile so that a constant ratio of rotational speed between lower circular plate  120  and second gear  130  can be maintained. In this way, the rotary motion of wind turbine  106  is transmitted to generator  108 , which in turn, generates a current to recharge battery  110 .  
     [0036]FIG. 4 is a cross-sectional view of battery-charging system  100  fitted on a roof  132  of an EV. Air enters battery-charging system  100  through grill  102  and is directed by air scoop  104  into wind turbine  106  during vehicular operation. Wind turbine  106  rotates around central spindle  124  and air escapes from wind turbine  106  via holes  126 . Air eventually exits battery-charging system  100  via a rear end  134  of a housing  136  of battery-charging system  100 . The upper end of central spindle  124  is connected by a plurality of bolts (not illustrated) and a plurality of nuts  138  to housing  136 . The lower end of central spindle  124  is connected by a plurality of bolts (not illustrated) and a plurality of nuts  140  to roof  132 .  
     [0037] Central spindle  124  transmits the rotary motion of wind turbine  106  to generator  108  when gear teeth  128  engage second gear  130  of generator  108 . The current generated by generator  108  recharges battery  110 . Generator  108  is attached to roof  132  by bolts (not illustrated) and nuts  142 . A piece of hard rubber  144  separates generator  108  from roof  132  and acts as a vibration absorber.  
     [0038] Each end of central spindle  124  is encased in a pair of cylindrical supports  146  and  148 . Cylindrical supports  146  and  148  are filled with lubricant  150 . Lubricant  150  is changed on a regular basis by draining the contents of cylindrical supports  146  and  148  through outlet  152  and adding fresh lubricant  150  through inlet  154  after about every 20,000 km of vehicular operation. Further lubrication of each end of central spindle  124  is achieved by employing a ball bearing system  156  thereat. Cylindrical support  146  attached to the lower end of central spindle  124  is secured to a strap bar  158  under roof  132 . A piece of hard rubber  160 , placed between cylindrical support  146  and roof  132 , acts as a vibration absorber.  
     [0039]FIG. 5 is a perspective view of an EV  200  in accordance with one embodiment of the present invention. A first battery-charging system  202  is fitted under the bonnet and a second battery-charging system  204  fitted on the roof. Air flows into first battery-charging system  202  via grill  206  and into second battery-charging system  204  through grill  208 . In addition, an optional air vent  210  may be mounted on top of the hood or bonnet of EV  200  to allow air exiting battery-charging system  202  to escape. Although a car is depicted in this embodiment, it is evident to a person of skill in the art that the battery-charging systems  202  and  204  may be fitted in other types of electric vehicles such as vans and buses as well. Further, it should also be appreciated that the roof and hood embodiments of the present invention may be consolidated to charge one battery-charging system in an EV.  
     [0040]FIG. 6 illustrates a method  300  of charging a battery according to one embodiment of the present invention. An EV is accelerated to a particular speed, preferably about 30 km/hour, so that a flow of air with sufficient volumetric flow rate to generate a force to turn a wind turbine is provided in a block  302  to a battery-charging system. The flow of air is directed in a block  304  to one side of a wind turbine where it exerts a force on the wind turbine. The wind turbine is rotated in a block  306  by the force exerted by the flow of air. The flow of air is released in a block  308  from the wind turbine through holes on the wind turbine. The rotary action of the wind turbine is transmitted in a block  310  to a generator and converted in a block  312  by the generator into electricity. A battery is charged in a block  314  by the electricity from the generator.  
     [0041] By utilizing the present invention, the operating range of an EV is extended because charging of the EV battery occurs even while the vehicle is in operation. An EV using the present invention will be able to travel greater distances before the energy stored in its battery is depleted to the extent that the EV has to stop for a recharge. As electricity is being generated while an EV employing the present invention is in operation, the chances that the battery of the EV needs to be fully recharged are reduced. In addition, the amount of recharging time when the vehicle is not in operation is reduced.  
     [0042] Although EVs are being presently heralded as ultra-low emission vehicles (ULEV), and in some instances, as zero-emission vehicles (ZEV), critics argue that this is inaccurate as such vehicles merely transfer emissions from a tailpipe to a smokestack. Because the present invention taps energy from a zero-emission source—wind power, an EV using the present invention is therefore even more environmentally friendly than conventional EVs.  
     [0043] Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention. Furthermore, certain terminology has been used for the purposes of descriptive clarity, and not to limit the present invention. The embodiments and preferred features described above should be considered exemplary, with the invention being defined by the appended claims.