Description:METHOD AND SYSTEM TO IMPROVE CHARGING EFFICIENCY OF ELECTRIC VEHICLE/ PLUG-IN HYBRID ELECTRIC VEHICLE
TECHNICAL FIELD
[0001] The present disclosure, in general, relates to charging of an electric vehicle/ plug-in hybrid electric vehicle. The present disclosure, particularly, relates to a method and a system to improve charging efficiency of an electric vehicle/ plug-in hybrid electric vehicle.

BACKGROUND
[0002] Electric vehicles, including hybrid vehicles, are of great interest for transportation applications and can provide benefits of low or zero emissions, quiet operation, and reduced dependence upon fossil fuels. Conventional batteries for electric vehicles may include lithium-ion batteries, nickel-metal-hydride batteries, cobalt dioxide batteries, and others. Common challenges associated with battery systems for electric vehicles include high capital cost of the batteries themselves, reductions in charging/discharging performance over time, reduction in energy storage capacity over time, and variability in performance among batteries.
[0003] To charge the battery system of electric vehicle/ plug-in hybrid electric vehicle, either of the personal or public charging systems can be used based on the need of the user. The existing charging systems, charges the battery systems with maximum possible rate. The maximum possible rate is either limited by the battery system or by the charger. If the vehicles are charged with higher rates, it leads to poor charging efficiency due to higher energy losses in the battery system and in the charger. The energy losses lead to increase in temperature of the battery system as well as the charger.
[0004] The battery system of a vehicle has a thermal system, which gets actuated when temperature of the battery reaches a predefined threshold. The thermal system consumes energy to bring the temperature of the battery or the charger below the predefined threshold. This contributes to charging losses.
[0005] For instance, a vehicle being charged at maximum power of 30kW. Continuing to charge the battery with maximum power will certainly increase the battery temperature above the predefined threshold. The thermal system gets activated and consume 2-3 kW to cool down the battery. This way battery system ends up consuming 5-10% more energy. Similar scenario could happen in charger also. It increases overall losses.
[0006] To solve these problems, optimization of charging rate is proposed in many existing systems. However, the problems discussed above still persist.
[0007] Accordingly, there is a need for a method and a system for improving charging efficiency of electric vehicle/ plug-in hybrid electric vehicle.

SUMMARY
[0008] This summary is provided to introduce concepts related to a method and a system to improve charging efficiency of electric vehicle/ plug-in hybrid electric vehicle. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0009] The present subject matter discloses a method to improve charging efficiency of electric vehicle/ plug-in hybrid electric vehicle. The method comprises determining, by a vehicle electronic control unit, estimated time to be spent by user at charging station; determining, by a battery management system, battery charging time of the vehicle; setting up, by the vehicle electronic control unit, the vehicle charging controller to charge the battery at a primogenial charging rate when the estimated time is greater than sum of the battery charging time and a marginal time; determining, by the battery management system, vehicle losses during charging of the battery at the primogenial charging rate; determining, by a charger controller, charger losses during charging of the battery at the primogenial charging rate; setting up, by the vehicle electronic control unit, the vehicle charging controller to charge the battery at a reduced charging rate than the primogenial charging rate in successive decrement steps when difference between the estimated time and charging time is more than the marginal time; determining losses including vehicle losses and charger losses during each successive decrement step; continuing, by the vehicle electronic control unit, charging the battery at a reduced charging rate than the last decremented charging rate in successive decrement steps till the difference between the estimated time and charging time is more than the marginal time and when the losses during last decrement step is less than the losses during penultimate decrement step; setting up, by the vehicle electronic control unit, the vehicle charging controller to charge the battery at an increased charging rate than the last decremented charging rate in successive increment steps when the losses during last decrement step is more than the losses during penultimate decrement step; determining losses including vehicle losses and charger losses during each successive increment step; continuing, by the vehicle electronic control unit, charging the battery at an increased charging rate than the last incremented charging rate in successive increment steps until battery temperature is below a predefined threshold and losses during last increment step is less than the losses during penultimate increment step; setting up, by the vehicle electronic control unit, the vehicle charging controller to charge the battery at a reduced charging rate than the last incremented charging rate in successive decrement steps when the losses during last increment step is more than the losses during penultimate increment step; repeating, by the vehicle electronic control unit, successive increment steps and successive decrement steps based on the real time vehicle losses, the real time charger losses and real time temperature of the battery until the battery is charged.
[0010] In an aspect, the vehicle electronic control unit set up the vehicle charging controller to charge the battery at an increased charging rate than the primogenial charging rate in successive incremental steps when difference between the estimated time and charging time is less than the marginal time.
[0011] In an aspect, the predefined threshold temperature is below activation temperature of a thermal system provided to avoid an increase in temperature of the battery.
[0012] In an aspect, during the successive increment step when the battery temperature increases above the predefined threshold temperature, the vehicle electronic control unit reduces the battery charging rate to maintain battery temperature below threshold while adhering to the estimated time.
[0013] In an aspect, determination of estimated time includes considering inputs from the user (user can manually input the amount of time vehicle will be connected to the charging station), charging history of user, preferences data, types of amenities used while charging, reservation information, GPS data of connected devices, trip planning information, etc.
[0014] In an aspect, the battery management system determines the battery charging time by considering battery targeted state of charge and current state of charge.
[0015] In an aspect, the vehicle losses include losses in battery cell, losses in busbar, losses in connector and losses in passive components of the battery.
[0016] In an aspect, the charger losses include stand-by losses and dynamic losses.
[0017] The present subject matter further relates to a system to improve charging efficiency of electric vehicle/ plug-in hybrid electric vehicle. The system comprises a battery having vehicle charging circuitry, a battery management system, a vehicle charging controller, a charger having charging circuitry, a charger controller and a vehicle electronic control unit. The battery having vehicle charging circuitry is operatively connected to a battery management system. The vehicle charging controller is provided to control the rate of charging of the battery and the battery management system is configured to determine battery charging time and vehicle losses during charging of the battery at each rate of charging. The charger having a charging circuitry is operatively connected to the charger controller. The charger controller is configured to determine charger losses during charging of the battery at each rate of charging. The vehicle electronic control unit is operatively connected to the battery management system and the vehicle charging controller of the battery and the charger controller of the charger. The vehicle electronic control unit is configured to: determine estimated time to be spent by user at charging station; set up the vehicle charging controller to charge the battery at a primogenial charging rate when the estimated time is greater than sum of the battery charging time and a marginal time; set up the vehicle charging controller to charge the battery at a reduced charging rate than the primogenial charging rate in successive decrement steps when difference between the estimated time and charging time is more than the marginal time; continuing charging the battery at a reduced charging rate than the last decremented charging rate in successive decrement steps till the difference between the estimated time and charging time is more than the marginal time and when the losses during last decrement step is less than the losses during penultimate decrement step; set up the vehicle charging controller to charge the battery at an increased charging rate than the last decremented charging rate in successive increment steps when the losses during last decrement step is more than the losses during penultimate decrement step; continue charging the battery at an increased charging rate than the last incremented charging rate in successive increment steps until battery temperature is below a predefined threshold and losses during last increment step is less than the losses during penultimate increment step; set up the vehicle charging controller to charge the battery at a reduced charging rate than the last incremented charging rate in successive decrement steps when the losses during last increment step is more than the losses during penultimate increment step; and repeating the successive increment steps and successive decrement steps based on the real time vehicle losses, the real time charger losses and real time temperature of the battery until the battery is charged.
[0018] In an aspect, the vehicle electronic control unit set up the vehicle charging controller to charge the battery at an increased charging rate than the primogenial charging rate in successive incremental steps when difference between the estimated time and charging time is less than the marginal time.
[0019] In an aspect, the predefined threshold temperature is below activation temperature of a thermal system provided to avoid an increase in temperature of the battery.
[0020] In an aspect, during the successive increment steps when the battery temperature increases above the predefined threshold temperature, the vehicle electronic control unit reduces the battery charging rate to maintain battery temperature below threshold while adhering to the estimated time.
[0021] In an aspect, determination of estimated time includes considering inputs from the user (user can manually input the amount of time vehicle will be connected to the charging station), charging history of user, preferences data, types of amenities used while charging, reservation information, GPS data of connected devices, trip planning information, etc.
[0022] In an aspect, the battery management system determines the battery charging time by considering battery targeted state of charge and current state of charge.
[0023] In an aspect, the vehicle losses include losses in battery cell, losses in busbar, losses in connector and losses in passive components of the battery.
[0024] In an aspect, the charger losses include stand-by losses and dynamic losses.
[0025] To further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit the scope of the present subject matter.
[0026] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF FIGURES
[0027] The illustrated embodiments of the present disclosure will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein:
[0028] FIG. 1 illustrates an exemplary system to improve charging efficiency of electric vehicle/ plug-in hybrid electric vehicle that can be utilized to implement one or more exemplary embodiments of the present disclosure;
[0029] FIGS. 2a and 2b illustrate a flow chart of the method system to improve charging efficiency of electric vehicle/ plug-in hybrid electric vehicle that can be utilized to implement one or more exemplary embodiments of the present disclosure; and
[0030] FIGS. 3a and 3b illustrate a flow chart followed by the working embodiment to improve charging efficiency of electric vehicle/ plug-in hybrid electric vehicle that can be utilized to implement one or more exemplary embodiments of the present disclosure.
[0031] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION
[0032] A few aspects of the present disclosure are explained in detail below with reference to the various figures. Example implementations are described to illustrate the disclosed subject matter, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a number of equivalent variations of the various features provided in the description that follows.

EXEMPLARY IMPLEMENTATIONS
[0033] While the present disclosure may be embodied in various forms, there are shown in the drawings, and will hereinafter be described, some exemplary and non-limiting embodiments, with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated. Not all of the depicted components described in this disclosure may be required, however, and some implementations may include additional, different, or fewer components from those expressly described in this disclosure. Variations in the arrangement and type of the components may be made without departing from the scope of the claims as set forth herein.
[0034] Some embodiments of this invention, illustrating all its features, will be discussed in detail.
[0035] The techniques described below may be implemented using one or more computer programs executed on (or executable by) a programmable computer including any combination of any number of the following: a processor, a sensor, a storage medium readable and/or writable by the processor (including for example volatile and non-volatile memory and/or storage elements), plurality of inputs units, plurality of output devices and networking devices.
[0036] Method steps as disclosed by present disclosure may be performed by one or more computer processors executing a program tangibly embodied on a computer-readable medium to perform functions of the invention by operating on input and generating output. Suitable processors include, by way of example, both general and special purpose microprocessors. Generally, the processor receives (reads) instructions and content from a memory (such as a read only memory and/or random access memory) and writes (stores) instructions and content to the memory. Storage devices suitable for tangibly embodying computer program instructions and content include, for example, all forms of non-volatile memory, such as semiconductor memory devices, including EPROM, EEPROM, and flash memory devices; magnetic disks such as internal hard disk and removable disks, magneto-optical disks, and CD-ROMs. Any of the foregoing may be supplemented by, or incorporated in, specially-designed ASICs (application specific integrated circuits) or FPGAs (Field-Programmable Gate Arrays).
[0037] Any content disclosed herein may be implemented, for example, in one or more content structures tangibly stored on a non-transitory computer-readable medium. Embodiments of the invention may store such content in such content structure(s) and read such content from such content structure(s).
[0038] The present disclosure provides a method and a system to improve charging efficiency of electric vehicle/ plug-in hybrid electric vehicle.
[0039] FIG. 1 illustrates an exemplary system to improve charging efficiency of electric vehicle/ plug-in hybrid electric vehicle that can be utilized to implement one or more exemplary embodiments of the present disclosure. The system 100 comprises a battery 101 having a vehicle charging circuitry 102, a battery management system 103, a vehicle charging controller 104, a charger 105 having a charger circuitry 106, a charger controller 107 and a vehicle electronic control unit 108. The battery 101 with the vehicle charging circuitry 102 is operatively connected to the battery management system 103. The battery management system 103 is configured to determine battery charging time and vehicle losses. The battery charging time is the time required to charge the battery 101. The battery management system 103 considers battery targeted state of charge (SOC) and battery current state of charge (SOC). The battery management system 103 includes losses in battery cell, losses in busbar, losses in connector and losses in passive components of the battery 101 to determine vehicle losses. The vehicle charging controller 104 is operatively connected to the vehicle charging circuitry 102 to control the rate of charging of the battery 101. The vehicle charging circuitry 102 includes at least a charging inlet 102a and a junction box 102b.
[0040] The charger 105 with a charging circuitry 106 is configured to charge the battery 101 of the vehicle. The charger 105 could be a charging station charger or an in-built vehicle charger. The charging circuitry 106 of the charger 105 is operatively connected to a charger controller 107. The charging circuitry 106 of the charger 105 includes AC input filter 106a, AC/DC converter 106b and DC/DC converter 106c. The charger controller 107 is configured to determine charger losses during charging of the battery 101. The charging controller 107 includes stand-by losses and dynamic losses to determine charger losses. The stand-by losses are constant and independent of current flow. The stand-by losses include hysteresis losses, eddy current losses, dielectric losses and thermal losses due to no-load current. The dynamic losses are dependent on current flow. The dynamic losses also known as joule effect are losses proportional to square of the current flowing through the components. Additionally, the charger controller 107 is also configured to control the rate of charging done by the charger 105.
[0041] The vehicle electronic control unit 108 is operatively connected to the battery management system 103 and vehicle charging controller 104 of the battery 101. The vehicle electronic control unit 108 is configured to receive battery charging time and vehicle losses in real-time as determined by the battery management system 103. In addition, the vehicle electronic control unit 108 is operatively connected to the charger controller 107 of the charger 105. The vehicle electronic control unit 108 is configured to receive charger losses from the charger controller 107. Further, the vehicle electronic control unit 108 is configured to determine estimated time to be spent by the user at charging station. The estimated time is determined by taking into consideration inputs from the user (user can manually input the amount of time vehicle will be connected to the charging station), charging history of user, preferences data, types of amenities used while charging, reservation information, GPS data of connected devices, trip planning information, etc. In addition to the estimated time and battery charging time, a marginal time is pre-stored in the vehicle electronic control unit 108. The marginal time depends on estimation accuracy of estimated time. If estimated time is highly accurate, marginal time is very low. But if estimated time accuracy is poor, then marginal time is higher. Based on the received parameters such as battery charging time, vehicle losses and charger losses, the determined parameters such as estimated time, and the pre-stored parameter such as marginal time, the vehicle electronic control unit 108 is configured to change the rate of charging of the battery 101 to improve charging efficiency of the electric vehicle/ plug-in hybrid electric vehicle.
[0042] In particular, the vehicle electronic control unit 108 is configured to set up the vehicle charging controller 104 to charge the battery at a primogenial charging rate when the estimated time is greater than sum of the battery charging time and the marginal time. Further, the vehicle electronic control unit 108 is configured to set up the vehicle charging controller 104 to charge the battery at a reduced charging rate than the primogenial charging rate when the difference between the estimated time and charging time is more than the marginal time. The reduction in charging rate is done in successive decrement steps. Each of the decrement step reduces the rate of charging by equal value. In an aspect, the vehicle electronic control unit 108 is configured to set up the vehicle charging controller 104 to charge the battery at an increased charging rate than the primogenial charging rate when the difference between the estimated time and charging time is less than the marginal time. The increase in charging rate is done in successive increment steps. Each of the increment step increases the rate of charging by equal value.
[0043] The battery management system 103 is configured to determine the vehicle losses at each and every rate of charging and the same is transmitted to the vehicle electronic control unit 108 in real time. Similarly, the charger controller 107 is configured to determine the charger losses at each and every rate of charging and the same is transmitted to the vehicle electronic control unit 108 in real time. The vehicle electronic control unit 108 is configured to receive the vehicle losses and charger losses in real time and accordingly change the rate of charging of the battery 101. For instance, the vehicle electronic control unit 108 continue to charge the battery at a reduced charging rate than the last decremented charging rate in successive decrement steps till the difference between the estimated time and the charging time is more than the marginal time and when the losses during the last decrement step is less than the losses during the penultimate decrement step.
[0044] When the losses during last decrement step is more than the losses during penultimate decrement step, the vehicle electronic control unit 108 set up the vehicle charging controller 104 to charge the battery 101 at an increased charging rate than the last decremented charging rate in successive increment steps. Further, the vehicle electronic control unit 108 is configured to continue charging the battery 101 at an increased charging rate than the last incremented charging rate in successive increment steps until battery temperature is below a pre-defined threshold and losses during last increment step is less than the losses during penultimate increment step. In an aspect, when the battery temperature is increased above the predefined threshold temperature during successive increment steps, the vehicle electronic control unit 108 reduces the battery charging rate as per the successive decrement steps to maintain temperature of the battery 101 below threshold while adhering to the estimated time.
[0045] A thermal system is provided to avoid an increase in temperature of the battery 101. The thermal system is actuated by the vehicle electronic control unit 108 at an activation temperature. The pre-defined temperature threshold is set below activation temperature of the thermal system. This eliminates the use of thermal system while charging, as the battery losses are reduced by reducing the charge rate before the activation temperature. This result in increasing charging efficiency as the thermal system does not consume any energy during charging.
[0046] Furthermore, when the losses during last increment step is more than the losses during penultimate increment step, the vehicle electronic control unit 108 is configured to set up the vehicle charging controller 104 to charge the battery 101 at a reduced charging rate than the last incremented charging rate in successive decrement steps. The incrementing and decrementing of the charging rate of the battery 101 is performed by the vehicle electronic control unit 108 based on the real time vehicle losses, the real time charger losses and the real time temperature of the battery 101 until the battery 101 is charged.
[0047] FIG. 2a and 2b illustrates a flow chart of the method 200 to improve charging efficiency of electric vehicle/ plug-in hybrid electric vehicle that can be utilized to implement one or more exemplary embodiments of the present disclosure.
[0048] At block 202, the method 200 includes determining estimated time. The estimated time is determined by the vehicle electronic control unit (108). The estimated time is the time spent by user at charging station. The estimated time is determined by taking into consideration inputs from the user (user can manually input the amount of time vehicle will be connected to the charging station), charging history of user, preferences data, types of amenities used while charging, reservation information, GPS data of connected devices, trip planning information, etc.
[0049] At block 204, the method 200 includes determining battery charging time. The battery charging time of the vehicle is determined by the battery management system 103. The battery charging time is the time required to charge the battery 101. The battery management system 103 considers battery targeted state of charge (SOC) and battery current state of charge (SOC).
[0050] At step 206, the method 200 includes setting up the vehicle charging controller 104 to charge the battery 101 at primogenial charging rate. The vehicle electronic control unit 108 set up the vehicle charging controller 104 to charge the battery 101 at a primogenial charging rate when the estimated time is greater than sum of the battery charging time and the marginal time. The marginal time depends on estimation accuracy of estimated time. If estimated time is highly accurate, marginal time is very low. But if estimated time accuracy is poor, then marginal time is higher. The marginal time is pre-stored in the vehicle electronic control unit 108.
[0051] At step 208, the method 200 includes determining vehicle losses at primogenial charging rate. The vehicle losses are determined by the battery management system 103. The battery management system 103 includes losses in battery cell, losses in busbar, losses in connector and losses in passive components of the battery 101 to determine vehicle losses.
[0052] At step 210, the method 200 includes determining charging losses at the primogenial charging rate. The charging losses are determined by the charger controller 107. The charging controller 107 includes stand-by losses and dynamic losses to determine charger losses. The stand-by losses are constant and independent of current flow. The stand-by losses include hysteresis losses, eddy current losses, dielectric losses and thermal losses due to no-load current. The dynamic losses are dependent on current flow. The dynamic losses are also known as joule effect are losses proportional to square of the current flowing through the components.
[0053] At step 212, the method 200 includes setting up the vehicle charging controller 104 to perform successive decrement steps on primogenial charging rate. The vehicle electronic control unit 108 is configured to set up the vehicle charging controller 104 to charge the battery 101 at a reduced charging rate than the primogenial charging rate when the difference between the estimated time and charging time is more than the marginal time. The reduction in charging rate is done in successive decrement steps. Each of the decrement step reduce the rate of charging by equal value. In an aspect, when the difference between the estimated time and charging time is less than the marginal time, the vehicle electronic control unit 108 set up the vehicle charging controller 104 to charge the battery 101 at an increased charging rate than the primogenial charging rate in successive incremental steps.
[0054] At step 214, the method 200 includes determining vehicle losses and charger losses during each successive decrement steps. The determination of vehicle losses and charger losses are performed as already discussed in steps 208 and 210. The only difference is that the vehicle losses and charger losses are now determined at each successive decrement steps.
[0055] At step 216, the method 200 includes continuing charging the battery 101 at reduced charging rate than the last decremented charging rate. Until the difference between the estimated time and charging time is more than the marginal time and when the losses during the last decrement step is less than the losses during penultimate decrement step, the vehicle electronic control unit 108 continue charging the battery 101 at the reduced charging rate than the last decrement charging rate in successive decrement steps,
[0056] At step 218, the method 200 includes setting up the vehicle charging controller 104 to perform successive increment steps on last decremented charging rate. When the losses during last decrement step is more than the losses during penultimate decrement step, the vehicle electronic control unit 108 set up the vehicle charging controller 104 to charge the battery 101 at an increased charging rate than the last decremented charging rate. The increased charging rate is implemented in successive increment steps.
[0057] At step 220, the method 200 includes determining vehicle losses and charger losses during each successive increment steps. The determination of vehicle losses and charger losses are performed as already discussed in steps 208 and 210. The only difference is that the vehicle losses and charger losses are now determined at each successive increment steps.
[0058] At step 222, the method 200 includes continuing charging the battery 101 at increased charging rate than the last incremented charging rate. Until the battery temperature is below a predefined threshold and losses during last increment step is less than the losses during penultimate increment step, the vehicle electronic control unit 108 continues to charge the battery 101 at an increased charging rate than the last incremented charging rate in successive increment steps. The predefined threshold temperature is below activation temperature of a thermal system provided to avoid an increase in temperature of the battery 101. Further, during successive increment steps, when the battery temperature increases above the predefined threshold temperature, the vehicle electronic control unit 108 reduces the battery charging rate to maintain battery temperature below threshold while adhering to the estimated time. In this way the method 200 ensures improving the charging efficiency.
[0059] At step 224, the method 200 includes setting up the vehicle charging controller 104 to perform successive decrement steps on last incremented charging rate. when the losses during the last increment step is more than the losses during penultimate incremented step, the vehicle electronic control unit 108 set up the vehicle charging controller 104 to charge the battery 101 at a reduced charging rate than the last incremented charging rate in successive decrement steps.
[0060] At step 226, the method 200 includes repeating successive increment steps and successive decrement steps until the battery is charged. Based on the real time vehicle losses, real time charger losses and real time temperature of the battery, the vehicle electronic control unit 108 repeats the successive increment steps and successive decrement steps as discussed in steps 212 and 218.
[0061] Description related to FIG. 1 has already discussed, in detail, the components of the system 100 including the battery 101 with charging circuitry 102, the charger 105 with charging circuitry 106, the battery management system 103, the vehicle charging controller 104, the charger controller 107 and the vehicle electronic control unit 108. Further, the estimated time, the battery charging time, the marginal time, the threshold temperature, the increment steps and the decrement steps are already discussed in detail in description related to FIG. 1. The method 200 works in the same way as already discussed for the system 100. Therefore, for the sake of brevity, the method 200 has not being explained in details.
WORKING EMBODIMENT
[0062] FIGS. 3a and 3b illustrates a flow chart followed by the working embodiment to improve charging efficiency of electric vehicle/ plug-in hybrid electric vehicle that can be utilized to implement one or more exemplary embodiments of the present disclosure.
[0063] The vehicle electronic control unit determines the estimated time. The battery management system determine battery charging time. The vehicle electronic control unit sets primogenial charging rate when the estimated time is greater than sum of the battery charging time and the marginal time. Equation 1 indicates primogenial charging rate.
Primogenial charging rate: (tcharge / test . tmargin) * Max charge rate……(1)
[0064] Let us consider that the primogenial charging rate is x coulomb/sec (C/s) or ampere (A).
[0065] The battery management system determines the vehicle losses at the primogenial charging rate.
[0066] The charger controller determines the charger losses at primogenial charging rate. The total losses include vehicle losses and charger losses. Let us consider the total losses as y watt (W).
[0067] The vehicle electronic control unit set up the vehicle charging controller to charge the battery at a reduced charging rate than the primogenial charging rate x, when the difference between the estimated time and charging time is more than the marginal time. The reduction in charging rate is done in successive decrement steps. Each of the decrement steps reduces the rate of charging by an equal value. Let us consider that each decrement step reduces the charging rate by z coulomb/sec or ampere. Thus, at first decrement step, the charging rate is x-z coulomb/sec or ampere. At second decrement step, the charging rate is x-2z coulomb/sec or ampere and so on. For keeping the explanation simpler, let us consider that two decrement steps are performed.
[0068] When the difference between the estimated time and the charging time is less than the marginal time, the vehicle electronic control unit 108 set up the vehicle charging controller 104 to charge the battery 101 at an increased charging rate than the primogenial charging rate in successive incremental steps. Each of the increment steps increases the rate of charging by an equal value. Let us consider that each increment step increases the charging rate by z coulomb/sec or ampere. Thus, at first increment step, the charging rate is x + z coulomb/sec or ampere. At second increment step, the charging rate is x + 2z coulomb/sec or ampere and so on.
[0069] Total losses are again determined at each decrement steps.
[0070] The battery is continued to be charged at reduced charging rate than the second decrement charging rate till the difference between the estimated time and charging time is more than the marginal time and when the losses during the last decrement step is less than the losses during penultimate decrement step. Let us consider that the difference between the estimated time and charging time is more than the marginal time and the losses during the last decrement step is less than the losses during penultimate decrement step. The vehicle electronic control unit continues to reduce the charging rate. The third decrement charging rate is x – 3z coulomb/sec or ampere.
[0071] The battery is charged at an increased charging rate than the third decrement charging rate when the losses during third decrement step is more than the losses during second decrement step. The first increment charging rate is x – 2z coulomb/sec or ampere. similarly, the second increment charging rate is x-z coulomb/sec or ampere.
[0072] Total losses are again determined at third increment charging rate.
[0073] The battery is continued to be charged at increased charging rate than the second increment charging rate until the battery temperature is below a predefined threshold and losses during second increment step is less than the losses during first increment step. Thus, the third increment charging rate is x coulomb/sec or ampere. Similarly, the fourth increment charging rate is x + z coulomb/sec or ampere.
[0074] The battery is charged at a reduced charging rate than the fourth increment charging rate when the losses during fourth increment step is more than the losses during third increment step. Thus, the first decrement charging rate is x coulomb/sec or ampere.
[0075] Similar increment and decrement steps are repeated until the battery is charged.
ADVANTAGES
[0076] The present disclosure provides a method and a system to improve charging efficiency of electric vehicle/ plug-in hybrid electric vehicle. The disclosed method and system optimize rate of charging of the battery based on estimated time to be spent by user at charging station, charger efficiency and battery efficiency. Further, the method and the system eliminate the use of thermal system to avoid an increase in temperature of the battery during charging. This increases the charging efficiency of the system and the method.
[0077] The above description does not provide specific details of the manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
[0078] It should be understood, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise, as apparent from the discussion herein, it is appreciated that throughout the description, discussions utilizing terms such as “receiving,” or “retrieving,” or “comparing,” or “generating,” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.
[0079] The exemplary embodiment also relates to a system for performing the operations discussed herein. This system may be specially constructed for the required purposes, or it may comprise a general-purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a computer-readable storage medium, such as, but is not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, solid state drives, magnetic or optical cards, or any type of media suitable for storing electronic instructions, and each coupled to a computer system bus.
[0080] Further, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0081] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[0082] It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
, Claims:We Claim:
1. A method (200) to improve charging efficiency of electric vehicle/plug-in hybrid electric vehicle, the method (200) comprises:
determining (202), by a vehicle electronic control unit (108), estimated time to be spent by user at charging station;
determining (204), by a battery management system (103), battery charging time of the vehicle;
setting up (206), by the vehicle electronic control unit (108), the vehicle charging controller (104) to charge the battery (101) at a primogenial charging rate when the estimated time is greater than sum of battery charging time and a marginal time;
determining (208), by the battery management system (103), vehicle losses during charging of the battery (101) at the primogenial charging rate;
determining (210), by a charger controller (107), charger losses during charging of the battery (101) at the primogenial charging rate;
setting up (212), by the vehicle electronic control unit (108), the vehicle charging controller (104) to charge the battery (101) at a reduced charging rate than the primogenial charging rate in successive decrement steps when difference between the estimated time and charging time is more than the marginal time;
determining (214) losses including vehicle losses and charger losses during each successive decrement step;
continuing (216), by the vehicle electronic control unit (108), charging the battery (101) at a reduced charging rate than the last decremented charging rate in successive decrement steps till the difference between the estimated time and charging time is more than the marginal time and when the losses during last decrement step is less than the losses during penultimate decrement step;
setting up (218), by the vehicle electronic control unit (108), the vehicle charging controller (104) to charge the battery (101) at an increased charging rate than the last decremented charging rate in successive increment steps when the losses during last decrement step is more than the losses during penultimate decrement step;
determining (220) losses including vehicle losses and charger losses during each successive increment step;
continuing (222), by the vehicle electronic control unit (108), charging the battery (101) at an increased charging rate than the last incremented charging rate in successive increment steps until battery temperature is below a predefined threshold and losses during last increment step is less than the losses during penultimate increment step;
setting up (224), by the vehicle electronic control unit (108), the vehicle charging controller (104) to charge the battery (101) at a reduced charging rate than the last incremented charging rate in successive decrement steps when the losses during last increment step is more than the losses during penultimate increment step;
repeating (226), by the vehicle electronic control unit (108), successive increment steps and successive decrement steps based on the real time vehicle losses, the real time charger losses and real time temperature of the battery (101) until the battery (101) is charged.
2. The method (200) as claimed in claim 1, wherein the vehicle electronic control unit (108) set up the vehicle charging controller (104) to charge the battery (101) at an increased charging rate than the primogenial charging rate in successive incremental steps when difference between the estimated time and charging time is less than the marginal time.
3. The method (200) as claimed in claim 1, wherein the predefined threshold temperature is below activation temperature of a thermal system provided to avoid an increase in temperature of the battery (101).
4. The method (200) as claimed in claim 1, wherein during the successive increment step when the battery temperature increases above the predefined threshold temperature, the vehicle electronic control unit 108 reduces the battery charging rate to maintain battery temperature below threshold while adhering to the estimated time.
5. The method (200) as claimed in claim 1, wherein determination of estimated time includes considering inputs from the user, charging history of user, preferences data, types of amenities used while charging, reservation information, GPS data of connected devices, trip planning information.
6. The method (200) as claimed in claim 1, wherein the battery management system (103) determines the battery charging time by considering battery targeted state of charge and current state of charge.
7. The method (200) as claimed in claim 1, wherein the vehicle losses include losses in battery cell, losses in busbar, losses in connector and losses in passive components of the battery (101).
8. The method (200) as claimed in claim 1, wherein the charger losses include stand-by losses and dynamic losses.
9. A system (100) to improve charging efficiency of electric vehicle/plug-in hybrid electric vehicle, the system (100) comprises:
a battery (101) having vehicle charging circuitry (102) operatively connected to a battery management system (103), wherein a vehicle charging controller (104) is provided to control the rate of charging of the battery (101) and the battery management system (103) is configured to determine battery charging time and vehicle losses during charging of the battery (101) at each rate of charging;
a charger (105) having a charging circuitry (106) operatively connected to a charger controller (107), wherein the charger controller (107) is configured to determine charger losses during charging of the battery (101) at each rate of charging; and
a vehicle electronic control unit (108) operatively connected to the battery management system (103) and the vehicle charging controller (104) of the battery (101) and the charger controller (107) of the charger (105), wherein the vehicle electronic control unit (108) is configured to:
determine estimated time to be spent by user at charging station;
set up the vehicle charging controller (104) to charge the battery (101) at a primogenial charging rate when the estimated time is greater than the sum of battery charging time and a marginal time;
set up the vehicle charging controller (104) to charge the battery (101) at a reduced charging rate than the primogenial charging rate in successive decrement steps when difference between the estimated time and charging time is more than the marginal time;
continuing charging the battery (101) at a reduced charging rate than the last decremented charging rate in successive decrement steps till the difference between the estimated time and charging time is more than the marginal time and when the losses during last decrement step is less than the losses during penultimate decrement step;
set up the vehicle charging controller (104) to charge the battery at an increased charging rate than the last decremented charging rate in successive increment steps when the losses during last decrement step is more than the losses during penultimate decrement step;
continue charging the battery (101) at an increased charging rate than the last incremented charging rate in successive increment steps until battery temperature is below a predefined threshold and losses during last increment step is less than the losses during penultimate increment step;
set up the vehicle charging controller (104) to charge the battery (101) at a reduced charging rate than the last incremented charging rate in successive decrement steps when the losses during last increment step is more than the losses during penultimate increment step; and
repeating the successive increment steps and successive decrement steps based on the real time vehicle losses, the real time charger losses and real time temperature of the battery (101) until the battery (101) is charged.
10. The system (100) as claimed in claim 9, wherein the vehicle electronic control unit (108) set up the vehicle charging controller (104) to charge the battery (101) at an increased charging rate than the primogenial charging rate in successive incremental steps when difference between the estimated time and charging time is less than the marginal time.
11. The system (100) as claimed in claim 9, wherein the predefined threshold temperature is below activation temperature of a thermal system provided to avoid an increase in temperature of the battery (101).
12. The system (100) as claimed in claim 9, wherein during the successive increment steps when the battery temperature increases above the predefined threshold temperature, the vehicle electronic control unit 108 reduces the battery charging rate to maintain battery temperature below threshold while adhering to the estimated time.
13. The system (100) as claimed in claim 9, wherein determination of estimated time includes considering inputs from the user, charging history of user, preferences data, types of amenities used while charging, reservation information, GPS data of connected devices, trip planning information.
14. The system (100) as claimed in claim 9, wherein the battery management system (103) determines the battery charging time by considering battery targeted state of charge and current state of charge.
15. The system (100) as claimed in claim 9, wherein the vehicle losses include losses in battery cell, losses in busbar, losses in connector and losses in passive components of the battery.
16. The system (100) as claimed in claim 9, wherein the charger losses include stand-by losses and dynamic losses.