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Title:
DYNAMIC MULTIPLEX SWITCHING SYSTEM FOR CHARGING AND DISCHARGING OF ELECTRIC VEHICLES
Document Type and Number:
WIPO Patent Application WO/2020/121339
Kind Code:
A1
Abstract:
The embodiments provide a multiplex switching system for EVs that facilitates sequential charging and discharging of two auxiliary power sources. The discharging power source supplies power to plurality of components of the EV while the other auxiliary power source simultaneously gets charged by the on-board primary battery. The functions of these auxiliary power sources get reversed once the discharging power source reaches a certain state of charge. In this way, the switching system helps to provide a facile and efficient way to extend the range of EVs.

Inventors:
VIVEK SINGHAL AKSHAY (IN)
KUMAR SHARMA ANSHUL (IN)
JAIN ANUJ (IN)
CHARAYA HEMANT (IN)
RAINA ANKUSH (IN)
S KIRAN (IN)
Application Number:
PCT/IN2019/050928
Publication Date:
June 18, 2020
Filing Date:
December 16, 2019
Export Citation:
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Assignee:
LOG 9 MATERIALS SCIENT PRIVATE LIMITED (IN)
International Classes:
B60L53/20; B60L53/80; B60L58/12; B60L58/18; H02J7/34
Domestic Patent References:
WO2015150219A12015-10-08
Foreign References:
US20130110337A12013-05-02
US20170072812A12017-03-16
Attorney, Agent or Firm:
PRABHU, Rakesh (IN)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. A multiplex switching system for electric vehicle comprising:

a plurality of battery packs mounted with two Battery monitoring system (BMS) modules selectively chosen to sequentially discharge the power to plurality of components through a plurality of battery power output lines, and alternatively to receive a power to charge a plurality of battery through plurality of battery power input line;

a battery switching circuit comprising a plurality of switches to supply power to plurality of components in the electric vehicle;

a microcontroller unit to control switching operation of the plurality of switches; and

a switching converter to regulate a power output supplied to the plurality of batteries by converting a unregulated power output to regulated power output.

2. The multiplex switching system according to claim 1, wherein the plurality of battery packs consists of a primary battery and a plurality of secondary batteries, and wherein the plurality of secondary battery includes a first secondary battery and a second secondary battery.

3. The multiplex switching system according to claim 2, wherein the primary battery is a galvanic cell selected from a group consisting of Aluminum-air battery, Zinc -air battery, Silicon-air battery, Alkaline cell or any other non-rechargeable primary battery thereof.

4. The multiplex switching system according to claim 2, wherein the secondary battery is a secondary cell selected from a group consisting of Nickel Cadmium, Nickel Metal Hydride and Lithium-Ion batteries, Sodium-Ion batteries, Ultra-capacitors, Hybrid Super-capacitors, Rechargeable Metal-Air Batteries, Redox Flow Batteries thereof.

5. The multiplex switching system according to claim 1, wherein the two Battery monitoring system (BMS) modules consist of a primary battery monitoring subsystem configured to monitor primary battery parameters and a secondary battery monitoring subsystem configured to monitor the secondary battery parameters.

6. The multiplex switching system according to claim 3, wherein the primary battery parameters includes terminal voltage, discharge current and all individual cell voltage, and wherein the primary battery parameters are used to identify a presence of main power source.

7. The multiplex switching system according to claim 3, wherein the secondary battery parameters includes charging and discharging current, terminal voltage and state of charge (SoC) or a charged level of a secondary battery, and wherein the secondary battery parameters are used to select the secondary batteries for charging and discharging operations or to enable or to disable the plurality of switches in the battery switching circuit.

8. The multiplex switching system according to claim 1, wherein the plurality of switches comprises a first switch, a second switch, a third switch, a fourth switch, a fifth switch and a sixth switch.

9. The multiplex switching system according to claim 1, wherein the microcontroller unit is configured to controls the battery switching circuit by controlling the switches.

10. The multiplex switching system according to claim 9, wherein the microcontroller unit receives the information on characteristics of the battery from the two Battery monitoring system (BMS) modules to select/ascertain the switches to be enabled and disabled and also to charges the secondary batteries.

11. The multiplex switching system according to claim 1, wherein the switching converter converts the unregulated power output generated by the primary battery to regulated power output, to charge the secondary batteries.

12. A method for charging and discharging the multiplex switching system of an electric vehicle comprises the steps of:

enabling/tuming-on a first switch to connect a power output line to any one of the main power lines, the first battery power output line and the second battery power output line to supply electrical power to a plurality of components in an electric vehicle;

enabling/tuming-on a second switch to connect a power input line selectively to a first battery power input line or to a second battery power input line, and wherein the second switch is enabled/tumed-on to connect the power input line to the first battery power input line to charge the first battery, and wherein the second switch is enabled/tumed-on to connect the power input line to the secondary battery power input line to charge the second battery;

enabling/tuming-on a third switch to connect the first battery to the power input line, to connect the first battery power input line to the primary battery for charging the first battery;

enabling/tuming-on a fourth switch to connect the first battery to the power output line, to the connect the first battery power output line to the plurality of components in the electric vehicle to supply electrical power to the plurality of components in the electric vehicle; enabling/tuming-on a fifth switch to connect the second battery to the power input line, to connect the second battery power input line to the primary battery to charge the secondary battery; and

enabling/tuming-on a sixth switch to connect the second battery to the power output line to connect a second battery power output line to the plurality of components in the vehicle to supply electrical power to the plurality of components in the electric vehicle.

13. The method of charging and discharging the multiplex switching system according to claim 12, wherein the plurality of batteries in a battery switching circuit is charged or discharged simultaneously or sequentially.

14. The method of charging and discharging the multiplex switching system according to claim 13, wherein the simultaneous charging method comprises:

enabling the second, third and fifth switches such that the first power output from the power adapter charges the second battery and the second power output from the power adapter charges the first battery;

enabling the first, second, third and sixth switches and disabling the fourth and fifth switches such that the primary battery supplies charge to the secondary batteries to supply power to the plurality of components through a main power line provided; and enabling the first, second, fourth and fifth switches and disabling the third and sixth switches such that the primary battery supplies power to charge the secondary batteries to supply power to the plurality of components through the main power line.

15. The method of charging and discharging the multiplex switching system according to claim 13, wherein the sequential charging and discharging method comprises:

enabling the first and fourth switches and disabling the sixth switch such that the first battery sequentially discharges the power to the plurality of components; enabling the first and sixth switches and disabling the fourth switch such that second battery sequentially discharges power to the plurality of components;

enabling the second and the third switches and disabling the fifth switch such that the first battery sequentially get charged; and

enabling the second and fifth switches and disabling the third switch such that the second battery sequentially get charged.

Description:
DYNAMIC MULTIPLEX SWITCHING SYSTEM LOR CHARGING AND

DISCHARGING OP ELECTRIC VEHICLES

CROSS-REFERENCE TO RELATED APPLICATIONS

[1] The present application claims the priority of the Indian Provisional Patent Application (PPA) with serial number 201811043054 filed on November 15, 2018 and subsequently postdated by 1 Month to December 15, 2018 with the title "MULTIPLEX SWITCHING SYSTEM FOR RANGE EXTENSION OF ELECTRIC VEHICLES". The contents of abovementioned PPA are included in entirety as reference herein.

BACKGROUND

Technical Field

[2] The embodiments herein are generally related to a field of electric vehicles. The embodiments herein are particularly related to a system and method for charging electric vehicles. The embodiments herein are more particularly related to battery switching circuit for simultaneous charging, sequential charging and sequential discharging of multiple batteries for extending range/mileage of electric vehicles, and a method for charging the batteries irrespective of technology.

Description of the Related Art

[3] A battery electric vehicle is an important way for replacing the existing fuel in vehicle. In order to travel for a long distance, a battery electric vehicle using lithium ion batteries needs to be installed with many lithium ion batteries because of a capacity limitation of lithium ion batteries, and which results in a notable increase in cost and weight of the vehicle. Further, a loading of the vehicles with several lithium ion batteries is very dangerous for a safety of the vehicle. [4] Hence, an insufficient capacity of lithium battery packs yields limited energy density is limited thereby creating a series of problems such as short traveling mileage or reduced mileage.

[5] However, an insufficient capacity of the rechargeable batteries is solved when there is constant on- board power source that is used to charge these batteries simultaneously as and when they are discharged.

[6] Hence, there is a need for a system and method for continuous charging of the batteries independent of the technology. Further there is a need for a system and method for simultaneous charging, sequential charging and sequential discharging of multiple batteries for extending range/mileage of electric vehicles.

[7] The abovementioned shortcomings, disadvantages and problems are addressed herein, which will be understood by reading and studying the following specification.

OBJECTIVES OF THE EMBODIMENTS HEREIN

[8] The primary object of the embodiments herein is to provide a system and method for simultaneous charging, sequential charging and sequential discharging of multiple batteries for extending range/mileage of electric vehicles, regardless of the technology

[9] Another object of the embodiments herein is to provide a circuit for supplying power to a plurality of components through a main power line within a vehicle, and wherein the circuit comprises a first battery selectively chosen to sequentially discharge power to the plurality of components through a first battery power output line, and alternatively to receive power to charge the first battery from the first battery power input line; a second battery selectively chosen to sequentially discharge power to the plurality of components through a second battery power output line, and alternatively to receive power to charge said second battery from a second battery power input line; and a primary battery that continuously provides power to said power input line. [10] Yet another object of the embodiments herein is to develop a system and method for simultaneous charging, sequential charging and sequential discharging of multiple batteries, and wherein the system is provided with a first switch connected to a power output line that is selectively coupled to one of the main power lines, said first battery power output line and said second battery power output line, to supply power to the plurality of components.

[11] Yet another object of the embodiments herein is to develop a system and method for simultaneous charging, sequential charging and sequential discharging of multiple batteries, and wherein the system is provided with a second switch and a power input line selectively coupled to said first battery power input line or said second battery power input line, to charge said first battery or second battery respectively.

[12] Yet another object of the embodiments herein is to provide the circuit comprising a third switch for selectively connecting said first battery to said first battery input line; a fourth switch for selectively connecting said first battery to said first battery output line; a fifth switch for selectively connecting said second battery to said second battery input line; and a sixth switch for selectively connecting said second battery to said second battery output line.

[13]Yet another object of the embodiments herein is to provide the circuit, to enable said first battery to sequentially discharge power to said plurality of components when said first switch and fourth switch are enabled and at least said sixth switch is disabled, and alternatively, to enable said second battery to sequentially discharge power to said plurality of components when said first switch and sixth switch are enabled and at least said fourth switch is disabled.

[14] Yet another object of the embodiments herein is to provide the circuit, to sequentially charge said first battery, when said second switch and third switch are enabled and at least said fifth switch is disabled, or, said sequentially charge second battery alternately when said second and fifth switch are enabled and at least said third switch is disabled.

[15]Yet another object of the embodiments herein is to provide the circuit, in which said first and second batteries forms a group of Secondary Cells and consists of Nickel Cadmium, Nickel Metal Hydride and Lithium-Ion batteries, Sodium-Ion batteries, Ultra capacitors, Hybrid Super-capacitors, Rechargeable Metal-Air Batteries, Redox Flow Batteries, etc.

[16] Yet another object of the embodiments herein is to provide the circuit, to allow said primary battery to supply power to charge said first battery while second battery supplies power to said plurality of components through said main power line, when said first, second, third and sixth are enabled and said fourth and fifth switches are disabled.

[17] Yet another object of the embodiments herein is to provide the circuit, to allow said primary battery to supply power to charge said second battery while first battery supplies power to said plurality of components through said main power line, when said first, second, fourth and fifth switches are enabled and said third and sixth switches are disabled.

[18] Yet another object of the embodiments herein is to provide the circuit, to simultaneously charge said first and second batteries with said primary battery, when said second, third and fifth switches are enabled so that said first power output from said power adapter charges said second battery and said second power output charges said first battery.

[19] Yet another object of the embodiments herein is to provide the circuit, with said primary battery for generating an unregulated power output and transmitting said unregulated power output through said cable line; and a regulator used on the cable line to supply a regulated power supply to charge the coupled battery input line. [20] Yet another object of the embodiments herein is to provide a microcontroller unit coupled to said battery switching circuit, to control said battery switching circuit, to control the switches which controls the main switches.

[21] Yet another object of the embodiments herein is to provide the circuit, with said primary battery (Galvanic Cell) consisting of Aluminum-Air Battery, Zinc-Air Battery, Silicon-Air Battery, Alkaline Cell or any other non-rechargeable primary battery.

[22] These and other objects and advantages of the embodiments herein will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.

SUMMARY

[23] The following details present a simplified summary of the embodiments herein to provide a basic understanding of the several aspects of the embodiments herein. This summary is not an extensive overview of the embodiments herein. It is not intended to identify key/critical elements of the embodiments herein or to delineate the scope of the embodiments herein. Its sole purpose is to present the concepts of the embodiments herein in a simplified form as a prelude to the more detailed description that is presented later.

[24] The other objects and advantages of the embodiments herein will become readily apparent from the following description taken in conjunction with the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

[25] The various embodiments herein provide an on-board charging system for a battery electric vehicle for increasing a traveling mileage of the battery electric vehicles. [26] According to one embodiment herein, the system is provided with a battery switching circuit to enable simultaneous charging and discharging of each battery pack and software that controls the switching based on the received inputs.

[27] According to one embodiment herein, the switching circuit supports the charging of secondary battery and discharging the secondary battery pack simultaneously.

[28] According to one embodiment herein, the circuit comprises main power input line which is further divided into a first power input line that is connected to the first battery pack, and a second power input line that is connected to the second battery pack.

[29] According to one embodiment herein, the main power output line which is further divided into a first power output line that is connected to the first battery pack, and a second power output line that is connected to the second battery pack.

[30] According to one embodiment herein, the main power input line is connected to the primary battery which is primarily dedicated to charge the secondary cells.

[31] According to one embodiment herein, the main power output line is connected to the plurality of components in the electric vehicle and primarily dedicated to discharge the secondary cells.

[32] According to one embodiment herein, the primary battery generates an unregulated power supply which is converted into regulated power supply through a regulator to charge the secondary cells.

[33] According to one embodiment herein, each of the two battery packs includes a monitoring circuitry for measuring a preset characteristics of the battery and a module for providing the system microcontroller information to assist the micro-controller in ascertaining/controlling/regulating or selecting the switches that are to be enabled or disabled. [34] According to one embodiment herein, the system micro-controller take in sensor inputs with respect to the battery packs to enables and disable the switches to charge the secondary batteries efficiently.

[35] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and arc intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[36] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:

[37] FIG. 1 illustrates a block circuit diagram of a battery switching circuit comprising the switches controlled by the microcontroller, according to an embodiment herein.

[38] FIG. 2 illustrates a block circuit diagram of a battery switching circuit for charging the battery for electric vehicle, according to an embodiment herein.

[39] FIG. 3illustrates a block circuit diagram of a charging-discharging circuit comprising a first battery discharging circuit and second battery charging circuit, according to an embodiment herein.

[40] FIG. 4illustrates a block circuit diagram of a charging-discharging circuit comprising the first battery charging circuit and the second battery discharging circuit, according to an embodiment herein.

[41] FIG. 5Aillustrates a flow chart explaining a method for sequential charging and discharging of multiple batteries, according to an embodiment herein. [42] FIG. 5Billustrates a flow chart explaining a method for simultaneous charging of multiple batteries, according to an embodiment herein.

[43] Although the specific features of the embodiments herein are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the embodiments herein.

DETAILED DESCRIPTION OF THE EMBODIMENTS HEREIN

[44] In the following detailed description, a reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.

[45] The embodiments herein provide an on-board charging system and method for a battery in an electric vehicle, for increasing a travelling mileage of the battery electric vehicle.

[46] The embodiments herein provide a charging and discharging system with a battery switching circuit for simultaneous charging, sequential charging and discharging of multiple batteries and a method for controlling a switching operation in charging discharging system/circuit based on the inputs received from a plurality of sensors in a battery monitoring circuit/system.

[47] The embodiments herein provide a battery switching circuit for a battery charging and discharging system/circuit used for simultaneous charging, sequential charging and discharging of the battery packs. The switching circuit is used for selecting/switching a battery within each battery pack. The embodiments herein further provide a plurality of methods for controlling a charging and discharging operation of the batteries. According to one embodiment herein, a battery switching circuit for supplying power to a plurality of components through a main power line within an electric vehicle comprises a plurality of battery packs provided with battery monitoring system (BMS) module. The plurality of the battery packs is selectively chosen to sequentially discharge the power to plurality of components through the plurality of battery power output lines, and alternatively to receive the power through plurality of battery power input lines to charge the plurality of batteries. The plurality of switches is provided in the battery switching circuit and selectively enabled to provide/supply power to plurality of components. A microcontroller unit is provided to control the battery switching circuit. A switching converter is arranged to regulate the power output by converting the unregulated power output to regulated power output.

[48] According to one embodiment herein, the plurality of battery packs consists of a primary battery and a plurality of secondary batteries. According to an embodiment herein, the plurality of secondary batteries is two in number. Each battery pack is provided with a Battery monitoring System (BMS). Two Battery monitoring system (BMS) modules are provided. The two Battery monitoring system (BMS) modules respectively consist of a primary battery monitoring subsystem to monitor a plurality of primary battery parameters and a secondary battery monitoring subsystem to monitor a plurality of secondary battery parameters. The primary battery monitoring subsystem is configured to measure the plurality of primary battery parameters such as terminal voltage, discharge current and all individual cell voltage, and wherein the primary battery parameters are used to identify a presence of main power source. The secondary battery monitoring subsystem is configured to measure a plurality of secondary battery parameters such as a charging and discharging current, a terminal voltage and a state of charge (SoC), and wherein the secondary battery parameters are used to select the batteries for charging and discharging operations or to enable or to disable (turn on/off) the switches. [49] According to one embodiment herein, the plurality of switches comprises a first switch, a second switch, a third switch, a fourth switch, a fifth switch and a sixth switch. The first switch is enabled to selectively connect a power output line to one of the main power lines, the first battery power output line from the first battery, and the second battery power output line from the second battery to provide electric power to the plurality of components in the electric vehicle. Further, the second switch is enabled to connect a power input line selectively to one of the two battery power input lines to charge the batteries. The second switch is enabled to couple the power input line to the first battery power input line to charge the first battery, and alternatively the second switch is enabled to couple the power input line to the second battery power input line to charge the second battery. Similarly, the third switch is enabled to connect the first battery to the power input line which is connected to the primary battery. The fourth switch is enabled to selectively connect the first battery to the power output line which is connected to the plurality of components in the vehicle. The fifth switch is enabled to selectively connect the second battery to the power input line which is connected to the primary battery. The sixth switch is enabled to selectively connect the second battery to the power output line which is connected to the plurality of components in the vehicle.

[50] According to one embodiment herein, the first battery sequentially discharges the power to the plurality of components in the electric vehicle, when the first switch and the fourth switch are enabled (turned on) and the sixth switch is disabled. The second battery sequentially discharges power to the plurality of components in the electric vehicle, when the first switch and the sixth switch are enabled and the fourth switch is disabled. Furthermore, the first battery is charged, when the second switch and third switch are enabled and the fifth switch is disabled. Alternatively, the second battery is charged, when the second switch and the fifth switch are enabled and the third switch is disabled. [51] According to one embodiment herein, during the operation, the two auxiliary power sources, such as first battery and second battery, are alternatively used to supply power to the plurality of components in the electric vehicle. While any one the first battery or the second battery is configured to discharge the supply power, the other battery is configured to be simultaneously charged by the primary battery. The roles of the batteries get reversed once when the battery in discharge mode reaches a preset state of charge (SOC).

[52] According to one embodiment herein, the primary battery is a galvanic cell selected from a group consisting of Aluminum-air battery, Zinc -air battery, Silicon-air battery, Alkaline cell or any other non-rechargeable primary battery thereof.

[53] According to an embodiment herein, the secondary battery in a group of secondary cell is selected from a group consisting of Nickel Cadmium, Nickel Metal Hydride and Lithium-Ion batteries, Sodium-Ion batteries, Ultra-capacitors, Hybrid Super capacitors, Rechargeable Metal-Air Batteries, Redox Flow Batteries thereof.

[54] According to an embodiment herein, the first and second batteries are simultaneously charged by the primary battery, when the second, third and fifth switches are enabled so that the first power output from the switching converter is used to charge the second battery and the second power output from the switching converter is used to charge the first battery. Further, the primary battery is configured to supply power or charge the secondary batteries for supplying power to the plurality of components in the electric vehicle through the main power line, when the first, second, third and sixth switches are enabled and the fourth and fifth switches are disabled. Alternately, the battery circuit allows the primary battery to supply power to charge the secondary batteries for supplying the power to the plurality of components in the electric vehicle through the main power line, when the first, second, fourth and fifth switches are enabled and the third and sixth switches are disabled. [55] According to an embodiment herein, the microcontroller unit is connected to the battery switching circuit to control the battery switching circuit by regulating the operation of the switches.

[56] According to an embodiment herein, the battery monitoring system (BMS) module in the plurality of battery packs measures the characteristics of the battery and further provides the measured information to the microcontroller. The microcontroller is configured to select/ascertains the switches to be enabled and disabled. Furthermore, the micro controller is configured to receive the inputs with respect to the plurality of battery packs from the Battery monitoring system to enable and disable the switches selectively to charge the secondary batteries efficiently.

[57] According to an embodiment herein, the switching converter is configured to convert the unregulated power output generated by the primary battery to regulated power output, which is then used to charge the secondary batteries. During the operation, the primary battery generates an unregulated power output and transmits the unregulated power output through the cable line. The switching converter is provided on the cable line to convert the unregulated power output to a regulated power output. The regulated power output is then used to charge the secondary batteries.

[58] According to an embodiment herein, a method for charging the battery of an electric vehicle through a battery switching circuit is provided. The method comprises turning on a first switch to connect a power output line to any one of the main power line, and the first battery power output line and the second battery power output line to supply power to the plurality of components in the electric vehicles. A second switch is turned on/enabled to connect a power input line to the first battery power input line selectively to charge the first battery. Alternatively the second switch is turned on/enabled to connect a power input line to the second battery power input line to charge the second battery. A third switch is enabled to connect the first battery to the power input line, thereby connecting the first battery power input line to the primary battery. A fourth switch is enabled to connect the first battery to the power output line, thereby connecting the first battery power output line to the plurality of components in the vehicle. A fifth switch is enabled/tumed on to connect the second battery to the power input line, thereby connecting the second battery power input line to the primary battery. A sixth switch is enabled/tumed on to connect the second battery to the power output line thereby connecting the second battery power output line to the plurality of components in the electric vehicle.

[59] According to an embodiment herein, the two secondary batteries comprising the first secondary battery and second secondary battery are alternatively used to supply power to the plurality of components in the electric vehicle. While the first battery or the second secondary battery is configured to discharge power to the plurality of components in the electric vehicle, the remaining secondary battery which is not used in discharge operation, is simultaneously charged by the primary battery. The roles of the secondary batteries get reversed once the secondary batteries reach a certain/pre-set (charging level) state of charge (Soc).

[60] According to an embodiment herein, the Switching Converter/Regulator present in between primary battery and secondary battery in the switching circuit, is configured to converter a unregulated power and/or voltage of the primary battery to a regulated power and/or voltage required by the secondary battery irrespective of their technology.

[61] According to an embodiment herein, the switches in the system with microcontroller and sensor is configured to acts as a safety device and isolate the faulty part of the system from the main healthy system during a detection of minor faults.

[62] According to an embodiment herein, the fuses and battery management/monitoring system are equipped with protective gears to act as a safety device. [63] According to an embodiment herein, two battery monitoring circuitry/modules (BMS) are provided. The two battery monitoring circuitry/modules (BMS) are provided respectively with a primary battery monitoring system and a secondary battery monitoring system. One of the subsystems monitors the primary battery parameters and another subsystem monitors the secondary battery parameters.

[64] According to an embodiment herein, the secondary battery monitoring subsystem is configured to measure the secondary battery parameters like charging and discharging current, terminal voltage and state of charge (SoC)/charged level. The secondary battery parameters are used to select the batteries for charging and discharging or otherwise used to enable or disable the switches.

[65] According to an embodiment herein, the primary battery monitoring subsystem is configured to measure the primary battery parameters like terminal voltage, discharge current and all individual cell voltage. The measured primary battery parameters are used to identify a presence of main power source.

[66] According to an embodiment herein, a battery monitoring system is the module present in each battery pack, to measure and/or monitor the battery parameters and to transmit the measured information to the microcontroller at regular time intervals and/or upon a request from the microcontroller. The received information with the code present in microcontroller is used to decide/select the operation of switches.

[67] According to an embodiment herein, an a algorithm is executed to carry out the steps of initialization of microcontroller and subsystems; scanning of all battery monitoring/management systems with the microcontroller to collect information about battery parameters; selection/decision to enable or disable the switches by the microcontroller based on the information collected from battery monitoring/management system, the code or software present in the microcontroller memory and the present switching circuit condition measured by the sensors. The scanning operation and the selectively turning on/off operation of the switches by the microcontroller are executed continuously in loops.

[68] According to an embodiment herein, the switching circuit comprises a single secondary battery. In this system, the primary battery, the secondary battery and the load are connected in parallel and operated together. All the switches in the system are enabled/tumed-on. The unregulated voltage of primary battery is regulated by a first set of switching converter to charge the secondary battery. The voltage at the secondary battery terminal various is varied based on the state of charge (SoC) or charged condition of the secondary battery. The second switching converter is used to stabilize the voltage at the load terminal to provide a constant/regulated voltage at load terminal.

[69] According to an embodiment herein, FIG.1 illustrates a battery switching circuit comprising a plurality of switches controlled by the microcontroller. With respect to FIG.1 the battery switching circuit 100 comprises a plurality of battery pack loaded with two battery monitoring system (BMS) modules. The plurality of battery packs is selectively chosen to sequentially discharge the power to the plurality of components 111 through the plurality of battery power output line, and alternatively to receive the power to charge the plurality of battery through plurality of battery power input line. The plurality of battery pack consists of a primary battery 109 and two secondary batteries 107 and 108. Further, the battery switching circuit consists of a plurality of switches to provide power to plurality of components 111. The plurality of components 111 is the load or the motor connected to the electric vehicle. The plurality of switches comprises the first switch 101, the second switch 102, the third switch 103, the fourth switch 104, the fifth switch 105 and the sixth switch 106. Furthermore, the battery switching circuit 100 comprises the microcontroller unit 110 to control the battery switching circuit, and the switching converter 112 to regulate the power output by converting the unregulated power output of the primary battery 109 to regulated power output which is then used to charge the secondary batteries 107 and 108. [70] According to an embodiment herein, the battery monitoring system module present in each battery pack, is configured to measure or monitor the battery parameters and transmit the measured information to the microcontroller at regular time intervals and/or upon a request from the microcontroller. The received information with the code present in microcontroller is used to select/decide the operation of switches. The microcontroller is loaded with an algorithm which is executed to select/judge/ascertain a switch to be enabled and disabled. The algorithm is executed to perform a method comprising the steps of initialization of microcontroller and subsystems; scanning of all battery monitoring/management systems with the microcontroller to collect information about battery parameters; selection/decision to enable or disable the switches by the microcontroller based on the information collected from battery monitoring/management system, the code or software present in the microcontroller memory and the present switching circuit condition measured by the sensors. The scanning operation and the selectively turning on/off operation of the switches by the microcontroller are executed continuously in loops.

[71] According to an embodiment herein, FIG.2 illustrates a block circuit diagram of battery switching circuit for charging the battery for electric vehicle. With respect to FIG.2 the battery switching circuit 200 comprises plurality of switches 201, 202, 203, 204,205 and 206; plurality of battery packs consisting of a primary battery 209 and two secondary batteries namely first battery 207 and second battery 208. Further the battery switching circuit comprises a plurality of components 210, wherein is the load or the motor connected to the electric vehicle, which receives the power from the secondary batteries 207 and 208 to run the vehicle. Furthermore, with respect to FIG.2, the first switch 201 is enabled to connect a power output line to any one of the main power lines, the first battery power output line and the second battery power output line to supply power to the plurality of components 210. The second switch 202 is enabled to connect a power input line selectively to the first battery power input line to charge the first battery 207. Alternatively, the second switch 202 is enabled to connect a power input line selectively to the second battery power input line to charge the second battery 208. The third switch 203 is turned on to connect the first battery 207 to the power input line, to connect the first battery power input line to the primary battery 209 to charge the first battery, The fourth switch 204 is turned on to connect the first battery 207 to the power output line, thereby connecting the first battery power output line to the plurality of components 210 in the vehicle to supply power to the plurality of components. The fifth switch 205 is turned on to connect the second battery 208 to the power input line thereby connecting the second battery power input line to the primary battery 209 to charge the secondary battery. The sixth switch 206 is turned on to connect the second battery 208 to the power output line to connect the second battery power output line to the plurality of components 210 in the vehicle.

[72] According to one embodiment herein, the first battery 207 and second battery 208 are configured to alternatively supply power to the plurality of components 210 in the electric vehicle. When any one of the first battery 207 and the second secondary battery 208 is configured to discharge the stored battery power to supply power to the plurality of components 210 in the electric vehicle, the remaining of the first and second secondary batteries 207 and 208 is simultaneously charged with the primary battery 209. Thus, the roles of the secondary batteries get reversed once the secondary batteries reach a certain state of charge (Soc) or a preset charged condition.

[73] According to an embodiment herein, FIG. 3 illustrates the block circuit diagram a switching circuit, when the first battery is in a discharging state and second battery is in a charging state. With respect to FIG.3, the first battery 307 is configured to discharge the stored battery power to deliver/supply the electric power to the plurality of components 310 in the electric vehicle, while the second battery 308 is simultaneously getting charged through the primary battery 309. Accordingly, the first and fourth switches 301 and 304 are turned on, the first battery 307 gets connected to main power output line and supplies power to plurality of components 310 in electric vehicle. When the second and fifth switches 302 and 305 are turned on, the second battery 308 gets connected to the main power input line to receive power from the primary battery 309.

[74] According to an embodiment herein, FIG.4 illustrates the block circuit diagram of a switching circuit indicating a charging operation with the first battery and a discharging operation with the second battery. With respect to FIG.4, the second battery 408 is in a discharging state to deliver stored electric power to the plurality of components 410 of the electric vehicle, while the first battery 407 is simultaneously charged through the primary battery 409. Accordingly, when the second and third switches 402 and 403 are enabled, the first battery 407 is connected to main power input line to receive power from the primary battery 409. When the first and sixth switches 401 and 406 are tumed-on, the second battery 408 is connected to main power output line to supply power to plurality of components 410 in the electric vehicle.

[75] According to one embodiment herein, FIG. 5A illustrates a flow chart explaining a sequential charging and discharging of multiple batteries. With respect to FIG.5A, the flow chart discloses the process steps executed during a sequential charging and discharging of multiple batteries. The sequential charging and discharging process comprises the following steps. In step-1 (502), the secondary batteries for charging and discharging are selected. In the step-2 (504), the selected secondary batteries for charging operation, are coupled to primary battery through switch converter and plurality of switches. Further in step-3 (506), the selected secondary batteries for discharging operation, are coupled to load or plurality of components through the switches. In the step-4 (508), the charged level in the secondary batteries is checked to find whether the charged level of the secondary batteries is less than a threshold level. At step-5 (510), all the secondary batteries are disconnected from primary battery, when the state of charge (SoC) of the discharging secondary batteries is less than threshold value. The charged secondary batteries are coupled to the load at step-6 (512). Further, the discharged secondary batteries are coupled to the primary battery for charging at step-7 (514). When the state of charge (SoC) of the discharging secondary batteries is not less than threshold value, then the process is continued from step-3 (506).

[76] According to one embodiment herein, FIG. 5B illustrates a flow chart explaining a simultaneous charging operation of multiple batteries. The simultaneous charging operation of multiple batteries comprises the following steps. In step-1 (516) the secondary batteries used for charging and discharging operations are selected. At step 2, (518), a judging operation is performed to check whether all the secondary batteries are selected for charging. When all the secondary batteries are selected for charging, then either a sequential charging operation is performed (520) or all the secondary batteries are coupled to primary battery for charging (522).

[77] Although the embodiments herein are described with various specific embodiments, it will be obvious for a person skilled in the art to practice the embodiments herein with modifications.

[78] The system and method for multiplex switching for range extension of electric vehicles disclosed in the embodiments herein have several exceptional advantages over existing techniques. Firstly, the proposed switching circuit facilitates charging and discharging the batteries simultaneously which possess following advantages.

[79] The proposed switching circuit greatly increases the traveling mileage of the battery electric vehicle. Further, the switching circuit provides safety, wherein the switches in the system with microcontroller and sensor acts as a safety device and isolates the faulty part of the system from the main healthy system at minor faults. Besides, the fuses and battery management/monitoring system are equipped with protective gears which act as a safety device. Moreover, the switching circuit solves the problems of long charging time for the lithium ion batteries and difficult charging brought about by fewer charging positions. [80] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such as specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

[81] It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modifications. However, all such modifications are deemed to be within the scope of the claims.