Claims:We claim:
1. A low voltage system (100) for an electric vehicle (EV), said system (100) comprises:
at least one low voltage battery unit (120) with Battery Management System (BMS) controller (102);
a drive motor (110) with a motor controller (108), and
a Vehicle Control Unit (VCU) (104) in communication with said at least one low voltage battery unit (120), said BMS controller (102) and said motor controller (108) over a Controller Area Network (CAN) bus (112, 114), characterized in that, said low voltage battery unit (120) is selected from a 12V battery unit or lower, and said low voltage battery unit (120) is used to power said drive motor (110).

2. The system (100) as claimed in claim 1 is provided without a DC-DC converter and a pre-charge circuit.

3. The system (100) as claimed in claim 1 is supported by any one of a portable charger and an on-board charger.

4. The system (100) as claimed in claim 1, wherein said low voltage battery unit (120) is any one of a fixed battery or swappable battery pack.

5. The system (100) as claimed in claim 1 is suitable for low speed vehicles with maximum speed upto 35km/hr.

6. The system (100) as claimed in claim 1, wherein said drive motor (110) is designed and made compatible with said low voltage battery unit (120).

7. The system (100) as claimed in claim 1, wherein said drive motor (110) is usable as generator for recuperation.

8. The system (100) as claimed in claim 1 is replacement of conventional 48V systems for low speed vehicles.
, Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed:

Field of the invention:
[0001] The present invention relates to a low voltage system for an electric vehicle.

Background of the invention:
[0002] There are no products that currently use low voltage systems (such as 12V) for traction applications in electric vehicles such as two wheelers. All the existing systems are 24-48V and above. The two wheeler vehicles in the sub 25kmph segment currently employ a 48V system. The choice of 48V system for these vehicles is driven by availability of 48V system and strong supplier base for 48V systems. These vehicles typically employ a 250W continuous power motor with a peak power of around 500W.

[0003] A patent literature CN206544473 discloses a power supply system for electric vehicle. The utility model relates to a power supply system for electric vehicle belongs to electric automobile's technical field. The utility model discloses a power supply system for electric vehicle, the 12V DC power supply who wraps through the interior power battery of placing in replaces the 12V battery. The on -vehicle machine that charges is connected with the power battery package, and the high voltage output end and the direct current conversion direct -current converter of power battery package are connected, the 12V DC power supply's that the power battery package embedded output passes through the low tension circuit to be changed direct -current converter, vehicle control unit, automobile body controller and not to have being connected with electrical apparatus of the normal electricity of needs such as key entering and start -up system with power management system, direct current, other low pressure for electrical apparatus of vehicle are connected to direct current conversion direct -current converter's output, and wherein the branch connects in parallel behind the diode to 12V DC power supply's output all the way. The utility model discloses a power supply system for electric vehicle has cancelled lead acid battery, can because of reducing by a bulky spare part, also be favorable to whole car general arrangement simultaneously so that whole car subtracts more than the heavy 10kg.

Brief description of the accompanying drawings:
[0004] An embodiment of the disclosure is described with reference to the following accompanying drawing,
[0005] Fig. 1 illustrates a block diagram of a low voltage system for an electric vehicle (EV), according to an embodiment of the present invention.

Detailed description of the embodiments:
[0006] Fig. 1 illustrates a block diagram of a low voltage system for an electric vehicle (EV), according to an embodiment of the present invention. The system 100 comprises at least one low voltage battery unit 120 with Battery Management System (BMS) controller 102, a drive motor 110 with a motor controller 108, and a Vehicle Control Unit (VCU) 104 in communication with the at least one low voltage battery unit 120, the BMS controller 102 and the motor controller 108 over a Controller Area Network (CAN) bus 112 (CAN high), 114 (CAN Low), characterized in that, the low voltage battery unit 120 is selected from a 12V battery unit or lower, and the low voltage battery unit 120 is used to power the drive motor 110 and other electronic accessories in the EV. In the system 100, n number of 12V batteries are shown connected in parallel. The auxiliaries 106 are connectable directly to the power net formed by the negative terminal 116 and positive terminal 118 of the low voltage battery unit 120. The drive motor 110 is a 12V compatible machine with corresponding 12V motor controller 108 in the system 100.

[0007] In accordance to the present invention, the VCU 104 comprises the memory element such as Random Access Memory (RAM) and/or Read Only Memory (ROM), Analog-to-Digital Converter (ADC) and a Digital-to-Analog Convertor (DAC), clocks, timers and at least one processor (capable of implementing machine learning) connected with each other and to other components through communication bus channels. The memory element is pre-stored with logics or instructions or programs or applications or modules and threshold values, reference values and conditions which is/are accessed by the processor as per the defined routines. The internal components of the VCU 104 are not explained for being state of the art, and the same must not be understood in a limiting manner. The VCU 104 may also comprise communication units to communicate with the cloud server through wireless or wired means such as Global System for Mobile Communications (GSM), 3G, 4G, 5G, Wi-Fi, Bluetooth, Ethernet, serial networks, and the like.

[0008] In accordance to an embodiment of the present invention, the VCU 104 is at least one of an internal control unit and an external control unit, where the external control unit is a control unit externally interfaced with the VCU 104. Examples of the VCU 104 is a smartphone, a wearable device, cloud, and the like.

[0009] According to the present invention, the system 100 is preferably for a low speed electric vehicle such as moped, motorcycles, scooters, auto-rickshaw, and the like.

[0010] According to an embodiment of the present invention, the low voltage system 100 is provided without a DC-DC converter and a pre-charge circuit. The system 100 is supported by any one of a portable charger and an on-board charger. The low voltage battery unit 120 is any one of a fixed battery or swappable battery pack. The system 100 is suitable for low speed electric vehicles with maximum speed up to 35 kmph. The system 100 is replacement of conventional 48V systems for low speed vehicles.

[0011] According to an embodiment of the present invention, the drive motor 110 is designed and made compatible with the low voltage battery unit 120. The drive motor 110 is usable as generator for recuperation which is controlled by the at least one of the VCU 104 and the motor controller 108.

[0012] According to the present invention, the low voltage system 100, i.e. 12V system 100 is a right technical fit for a vehicle class which employs 48V systems. Now the 12V will be used as low voltage for further explanation of the system 100 but is not limited to the same. Typically, the 48V systems employ a DC-DC converter to step down 48V to 12 V. Because the 12V is required for the functioning of the auxiliaries 106 in the system 100. But in the 12V system 100 as disclosed in the present invention, the DC-DC converter is not required since the operating voltage of the traction/drive motor 110 and the motor controller 108 is also at 12V. The 12V traction system 100 greatly simplifies system engineering complexity by reducing number of components, weight of system 100 and its integration requirements. The DC-DC converter is omitted and there is scope to eliminate onboard charger in favor of a portable charger. For example, a 620Wh 12V pack helps achieve weight reduction (30kms range) with option to use single or double low voltage battery units 120 as per range requirement. A shift to portable low voltage battery unit 120 leads to further flexibility to an Original Equipment manufacturer (OEM), as the OEM is able to eliminate the onboard charger in the vehicle. The reduction in weight of the system 100 leads to improvement in energy efficiency of the EV. Further, the portable low voltage battery units 120 are usable in the EV. The 12V system 100 is mainly targeted towards but not limited to Logistic Service Providers (LSP). The portable low voltage battery units 120 allows the LSPs to deploy a bulk charger to charge the low voltage battery units 120. This allows the OEM to eliminate the onboard charger on the EV.

[0013] According to the present invention, the hardware and software of the BMS controller 102 is optimized for the low power application, as a result, the common features such as pre-charge is omitted for this application. The BMS controller 102 has the auto detection of battery pack configuration feature which allows multiple battery packs to be operated in a parallel configuration. The 12V system 100 provide significant cost advantage over the incumbent 48V solution. The 12V system 100 reduces the vehicle weight and thus provide a better efficiency of the system 100. The performance of a Battery Disconnect Unit (BDU) in the BMS controller 102 is at par with the state of the art MOSFET based disconnect units used in the current 48V BMS controller.

[0014] In a working example, the 12V 50Ah system 100 (such as a single low voltage battery unit 120 in two-wheeler application), can operate upto currents of 100A. The optimized BDU design allows the system 100 to operate at peak currents of up to 100A and continuous currents of 60A. This is a previously unexplored application for low speed 12V two wheelers which always use systems 100 that are 48V and above to provide high speed and performance requirements. The 12V electric two wheelers finds applications in the logistics delivery segment where speeds of 25-35kmph with a range of 60kms (using two low voltage battery units 120) or 30kms (using one low voltage battery unit 120) with the system 100 to automatically identify number of batteries connected.

[0015] According to the present invention, the 12V system 100 for low speed electric vehicle traction application is provided. The current 48V is the state of the art, for low speed mobility applications upto 35kmph, whereas the low voltage system 100 architecture of the present invention is disclosed to provide a novel, low-cost, safe, and easy to integrate solution. Based on the usage profile and thrust on proliferation of EVs, the system 100 provides a quick recharging alternate for a given range need. The efficient low voltage system 100 paired with an innovative low voltage battery unit 120 (lithium ion) solution described in this disclosure is scalable to other adjacent applications like smart trolleys, medical equipment, baby stroller, golf caddy, push cart, (four 12V batteries in series in a golf cart), marine batteries, Starting, Lighting and Ignition (SLI) batteries in automotive, wheelchair assistance systems, hospital beds with electronic assistance, solar grid batteries, etc. The present invention provides the right configuration with which the low voltage system 100 enables functional performance in a low speed two wheeler (25-35kmph) and significantly reduce the configuration complexity of the system 100.

[0016] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.