FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
BATTERY SYSTEM FOR HYBRID VEHICLES
MAHINDRA TWO WHEELERS LTD.,
an Indian Company of D-1 block, plot no. 18/2, chinchwad, Pune - 411 019, Maharashtra India.
Inventors: 1. KAKAYE SUNIL 2. AHMED SABIR
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

FIELD OF DISCLOSURE
The present disclosure relates to a battery system for a hybrid vehicle.
BACKGROUND
A hybrid vehicle comprises two or more distinct power sources, typically, including an internal combustion engine and one or more electric motors. Based on the degree of hybridization several powertrain configurations such as parallel hybrid configuration, full parallel hybrid configuration and the like are utilized to power hybrid vehicles.
Generally, a parallel hybrid configuration is used in hybrid vehicles wherein two power sources are installed in a manner to power hybrid vehicles either individually or in combination. The two power sources are connected in parallel to each other to provide an output torque which is a combination of torque achieved by the use of the two power sources. The electric powertrain implements a battery that is used to supply electric power to an electric motor and the same battery is also utilized for other applications in a vehicle like ignition of the vehicle, powering of DC loads such as indicator lights, headlamps, turn lights and the like.
However, use of a single battery for various purposes such as driving the electric motor, for ignition of the vehicle and for powering DC loads of the vehicle, leads to quick discharge of the battery and hence necessitates frequent charging of the battery. Frequent charging of the battery reduces battery life and causes a steady decline in the ability of the battery to produce electrical energy. Moreover, since starting of the hybrid vehicle is entirely dependent on the output power of the electric motor, if the battery has insufficient power for energizing the electric motor, then the vehicle does not have a smooth start, thus deteriorating the performance of the vehicle. Conventionally, an integrated starter generator is incorporated in hybrid vehicles to crank an IC engine that makes the overall system complex, expensive and inefficient. Moreover, parallel connection of two power sources leads to substantial inefficiency

under conditions wherein only one power source is used to power the vehicle, as the other non-used power source operates in an idling manner.
Hence there is a need to alleviate the aforementioned drawbacks associated with conventional vehicles implementing parallel hybrid configuration. There is a need to address drawbacks associated with use of integrated starter generators and to efficiently manage use of the battery to reduce load on the battery, thus increasing battery life. There is also a need to improve the existing control systems of hybrid vehicles to efficiently manage hybrid implementation in vehicles, improve the efficiency of the engine and reduce emissions by vehicles.
OBJECTS
Some of the objects of the battery system of the present disclosure are aimed to ameliorate one or more problems of the prior art or to at least provide a useful alternative and are listed herein below.
An object of the battery system of the present disclosure is to effectively monitor and efficiently control charging of a traction battery and a 12V rechargeable battery associated with a hybrid vehicle.
Yet another object of the battery system of the present disclosure is to reduce load on a traction battery associated with a hybrid vehicle.
Still another object of the battery system of the present disclosure is to reduce emissions by hybrid vehicles.
One more object of the battery system of the present disclosure is to increase efficiency of engines of hybrid vehicles.

An additional object of the battery system of the present disclosure is to provide an onboard charger for a battery of a hybrid vehicle.
Another object of the battery system of the present disclosure is to achieve hybridization using conventional components.
Still another object of the battery system of the present disclosure is to achieve a cost effective hybrid vehicle.
Other objects and advantages of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the present disclosure.
SUMMARY
A battery system for a hybrid vehicle utilizing an internal combustion engine and a traction motor is disclosed. The battery system includes:
• at least one primary battery co-operating with the traction motor, the at least one primary battery adapted to be charged by an electrical generator driven by the internal combustion engine;
• at least one secondary battery adapted to selectively receive regulated electrical power from the at least one primary battery; and
• a controller adapted to monitor state of charge of the at least one secondary battery and further adapted to enable and disable reception of the regulated electrical power by the at least one secondary battery corresponding to the monitored state of charge.
Typically, the controller is an engine control unit.
Alternatively, the controller is a microprocessor.

Additionally, the controller comprises a battery management system to monitor the state of charge of the at least one secondary battery.
In accordance with an embodiment of the present disclosure, the at least one primary battery is co-operating with the traction motor via at least one power electronic device.
Further, the regulated electrical power is obtained by a power converter coupled between the at least one primary battery and the at least one secondary battery.
Additionally, the at least one secondary battery is adapted to drive ignition system and electrical loads of the hybrid vehicle.
Typically, the electrical generator is an alternator.
Alternatively, the electrical generator may be a magneto,
Additionally, the battery system of the present disclosure comprises a regulator-rectifier unit co-operating with the electrical generator and the at least one primary battery, the regulator-rectifier unit adapted to receive alternating current from the electrical generator and generate a direct current to charge the at least one primary battery.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWING
The battery system of the present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a block diagram of the architecture of a battery system, in accordance with an embodiment of the present disclosure, for hybrid vehicles.

DETAILED DESCRIPTION
The battery system of the present disclosure will now be described with reference to the embodiment shown in the accompanying drawing. The embodiment does not limit the scope and ambit of the disclosure. The description relates purely to the example and preferred embodiment of the disclosed method and its suggested application.
The battery system and the various features and advantageous details thereof are explained with reference to the non-limiting embodiment in the following description. Descriptions of well-known parameters and processing techniques are omitted so as to not unnecessarily obscure the embodiment herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiment herein may be practiced and to further enable those of skill in the art to practice the embodiment herein. Accordingly, the examples should not be construed as limiting the scope of the embodiment herein.
Figure 1 illustrates a block diagram of the architecture of a battery system 100, in accordance with an embodiment of the present disclosure, for hybrid vehicles. The battery system 100 of the present disclosure is described particularly with reference to a two wheeled vehicle, but also includes four wheeled vehicles, three wheeled vehicles and the like, and is not intended to limit the scope of the present disclosure. In accordance with an embodiment of the present disclosure, hybrid vehicle powertrain system includes a first prime mover such as petrol or gasoline powered internal combustion engine 104 of typically, 110 CC as a source of mechanical power and a second prime mover such as a traction motor 106 as a source of electrical power. The battery system 100 includes a primary battery 114 typically a traction battery and a secondary battery 110 typically a 12 V rechargeable battery. The secondary battery 110 selectively receives electrical power from the primary battery 114 in order to get charged. To maintain an adequate level of charge in the primary battery 114, the hybrid vehicle includes an electrical generator 116 that generates an electrical power to charge the primary battery 114. Typically, the electrical generator

116 is a magneto driven by the internal combustion engine 104 in order to generate an alternating current. The generated alternating current is further provided to a charging mechanism typically a regulator-rectifier unit 124 rated (48V/20A) that regulates and rectifies the received alternating current to generate a direct current. The generated direct current is further provided to the primary battery 114 to enable charging thereof.
The battery system 100 includes a controller 102 typically an engine control unit incorporating a microprocessor processing signals received from various sensors installed in the hybrid vehicle in order to sense and monitor associated functions of the hybrid vehicle. Typically, the charging of the secondary battery 110 is controlled by the controller 102 which selectively enables transmission of electrical power to the secondary battery 110. The hybrid vehicle in the illustrated embodiment is equipped with a high voltage primary battery 114, typically rated at 48V/10Ah that provides electrical power to the traction motor 106. Further, the primary battery 114 is utilized to charge secondary battery 110 typically rated 12V/6Ah. The secondary battery 110 selectively receives regulated electrical power from the primary battery 114, wherein the selective reception of the regulated electrical power is controlled by the controller 102. The regulated electrical power is obtained with the help of a power converter 108 typically a DC-DC converter which steps down the direct current voltage from 48V to 12V. The controller 102 controls the reception of the regulated electrical power by the secondary battery 110 based on State Of Charge (SOC) of the secondary battery 110. The SOC is an index monitored by the controller 102 to estimate charge level of the secondary battery 110. In an event of monitored SOC falling below a pre-determined level, the controller 102 generates a control signal 128 that enables the reception of regulated electrical power by the secondary battery 110. In an event of monitored SOC maintained above a pre-determined level, the controller 102 generates the control signal 128 that disables the reception of regulated electrical power by the secondary battery 110, thereby precluding overcharging of the secondary battery 110 and thus reducing load on the primary battery 114. The secondary battery 110 is typically utilized to drive electrical loads 122 of the hybrid vehicle such as indicators, head lamp, tail lights and the like. Moreover, the secondary battery 110 is also used in an

ignition system of the hybrid vehicle by energizing a start motor 105, typically rated at 12V/0.3KW for driving the internal combustion engine 104 via a switch 118. The operation of the switch 118 is controlled by a control signal 164 generated by the controller 102, The generation of the control signal 164 depends on the monitored SOC of the secondary battery 110 carried out by the controller 102 via a control signal 126. The SOC of the primary battery 114 is also determined by the controller 102 typically by calculating various parameters such as voltage, temperature and current of the traction battery 114 through a control signal 130. Typically, the controller 102 is assisted by a battery management system associated with the primary battery 114 and the secondary battery 110 in estimating and controlling the state of the battery by measuring SOC of the battery.
A plurality of power electronic devices 112 typically associated with motor drive, regenerative braking charging and inverter circuits are controlled by the controller 102 though a control signal 134. The power electronic devices 112 are powered by the primary battery 114 to control the traction motor 106 typically a brushless DC electric motor (BLDC) rated 48V/ 1KW and providing a torque of 10Nm. The state and speed of the traction motor 106 is sensed by the controller 102 through a control signal 136. The state of the inverter circuit is monitored by the controller 102 through a control signal 132. A Capacitor Discharge Ignition (CDI) unit 120 is controlled by a control signal 168.
The hybrid vehicle utilizing the battery system in accordance with an embodiment of the present disclosure incorporates a full series hybrid powertrain, thus making it more efficient as compared to the conventional hybrid vehicle using parallel hybrid powertrain. The secondary battery 110 is utilized to crank the internal combustion engine 104, typically a petrol engine, thus reducing complexity of the present system as compared to battery systems associated with conventional hybrid vehicles using integrated starter generators. The controller 102 generates signals corresponding to various parameters of the hybrid vehicle, the typical parameters are listed herein below:

• engine rpm 138;
• speed sensor 140;
• side stand SW 142;
• TPS/Accelerator 144;
• drive/neutral/reverse SW 146;
• brake SW 148;
• crank 150; and
• IGN 152.
Typical control signals generated by the controller 102 to control various other devices associated with a hybrid vehicle in accordance with an embodiment of the present disclosure are listed herein below.
• rpm I/P to speedometer 154;
• speed I/P to speedometer 156;
• hybrid ready 158;
• check Hybrid Indication 160; and
• stop Hybrid Indication 162.
The battery system of the present disclosure provides an onboard charger for the primary battery 114 in the form of the internal combustion engine 104, thereby eliminating a need for charging the primary battery 114 externally from an alternating current power outlet as is required in the case with conventional hybrid vehicles. Moreover, the hybrid vehicle can be configured to be driven purely on an electric powertrain by switching OFF the internal combustion engine 104 for a pre-determined time duration, thereby producing zero emission. Furthermore, hybridization in the hybrid vehicle using the battery system of the present disclosure is achieved by using conventional components, thereby making the hybrid vehicle cost effective. The internal combustion engine of the hybrid vehicle in accordance with the present disclosure runs at a constant speed thereby resulting in reduced emissions and increased efficiency.

Although the battery system of the present disclosure is described with reference to the illustrated architecture, other configurations of the battery system are included in the scope of the present disclosure.
TECHNICAL ADVANCEMENTS AND ECONOMIC SIGNIFICANCE
The technical advancements offered by the present disclosure include the realization of a battery system for a hybrid vehicle characterized by:
• efficient and cost effective ignition system;
• effective monitoring and charging of batteries;
• reduced load on a traction battery;
• reduced emissions by hybrid vehicles;
• increased internal combustion engine efficiency;
• achieved hybridization using conventional components; and
• on board charger to charge traction battery.
Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.

Wherever a range of values is specified, a value up to 10% below and above the lowest and highest numerical value respectively, of the specified range, is included in the scope of the disclosure.
The foregoing description of the specific embodiment will so fully reveal the general nature of the embodiment herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiment 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 embodiment. 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 embodiment herein has been described in terms of preferred embodiment, those skilled in the art will recognize that the embodiment herein can be practiced with modification within the spirit and scope of the embodiment as described herein.

We Claim:
1. A battery system for a hybrid vehicle utilizing an internal combustion engine
and a traction motor, said system comprising:
• at least one primary battery co-operating with the traction motor, said at least one primary battery adapted to be charged by an electrical generator driven by the internal combustion engine;
• at least one secondary battery adapted to selectively receive regulated electrical power from said at least one primary battery; and
• a controller adapted to monitor state of charge of said at least one secondary battery and further adapted to enable and disable reception of said regulated electrical power by said at least one secondary battery corresponding to said monitored state of charge.

2. The system as claimed in claim 1, wherein said controller is an engine control unit.
3. The system as claimed in claim 1, wherein said controller is a microprocessor.
4. The system as claimed in claim 1, wherein said controller further comprises a battery management system to monitor said state of charge of said at least one secondary battery.
5. The system as claimed in claim 1, wherein said at least one primary battery is adapted to co-operate with the traction motor via at least one power electronic device.
6. The system as claimed in claim 1 further comprises a power converter coupled between said at least one primary battery and said at least one secondary battery to provide said regulated electrical power.
7. The system as claimed in claim 1 wherein said at least one secondary battery is further adapted to drive ignition system and electrical loads of the hybrid vehicle.

8. The system as claimed in claim 1 wherein said electrical generator is an alternator.
9. The system as claimed in claim 1 wherein said electrical generator is a magneto.
10. The system as claimed in claim 1 further comprises a regulator-rectifier unit
co-operating with said electrical generator and said at least one primary battery,
said regulator-rectifier unit adapted to receive alternating current from said
electrical generator and generate a direct current to charge said at least one
primary battery.