TECHNICAL FIELD
[0001] The present disclosure, in general, relates to the internal
temperature of the battery installed in a vehicle. In particular, the present
disclosure relates to a system and method for determining the internal
temperature of the battery installed in a vehicle.
BACKGROUND OF THE INVENTION
[0002] Atypical internal combustion engine of a vehicle includes a battery that provides power to one or more vehicle electrical systems. When the battery is providing power to one or more of the vehicle's electrical systems, the power drain on the battery reduces the battery charge, and thus its voltage output. When the vehicle is running, a vehicle alternator recharges the battery so that the battery charge is high enough for continued power output to the vehicle's electrical systems. The greater the power drain on the battery, the more charging is needed for the battery from the alternator. To control the charging output of the alternator, a field control input signal from a controller sets the duty cycle of the alternator depending on the drain on the vehicle battery. This field control of the alternator is referred to as the electronic voltage regulating (EVR) of a vehicle battery charging system.
[0003] Battery temperature is an important parameter for providing battery charging control. The temperature of the vehicle battery is required to determine an accurate EVR set point for proper battery charging. A proper set point for the desired battery target voltage will prevent the battery from overheating at high battery temperatures during charging, and prevent the battery from being undercharged at low battery temperatures during charging.
[0004] For current vehicle technology, a battery temperature sensor, such as a temperature coefficient sensor, is mounted outside of the vehicle battery, usually on the battery or near it.. Because the sensor is mounted outside of the battery, the temperature measurement is severely affected by the

surrounding environment and therefore does not accurately reflect the dynamic variations of the battery's internal temperature. The inability to accurately measure a vehicle battery's temperature adversely affects the recharging of the battery. Moreover, the already existing method and the system fail to consider the impact of change in battery ambient temperature while calculating the temperature of the battery. This leads to high errors while calculating the battery temperature.
[0005] Hence, there is a need for the system and the method that effectively measure the battery temperature by taking the variation in the battery ambient temperature into consideration.
OBJECTS OF THE DISCLOSURE
[0006] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed hereinbelow.
[0007] It is a general or primary object of the present disclosure to provide a system that facilitates the effective determination of a battery temperature by taking variation in an ambient temperature of a battery into consideration.
[0008] It is another object of the present disclosure to provide a method that also facilitates the effective determination of a battery temperature.
[0009] It is another object of the present disclosure to configure the system inside a vehicle in such a manner that facilitates the effective and easy determination of the battery temperature.
[0010] It is yet another object of the present disclosure to provide the system with high performance and reliability.
[0011] It is a further object of the present disclosure to provide a cost-effective and efficient system.
[0012] These and other objects and advantages of the present disclosure will be apparent to those skilled in the art after a consideration of the following

detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present disclosure is illustrated.
SUMMARY
[0013] This summary is provided to introduce concepts related to a system and a method that facilitates the effective determination of a battery temperature by taking variation in an ambient temperature of a battery into consideration. 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.
[0014] In an embodiment, the present disclosure provides a system for estimating a battery temperature. The system includes a memory unit storing an intermediate battery temperature of a battery, said intermediate battery temperature is based on an ambient temperature and a coefficient of vehicle speed. The system further includes a processing unit, coupled to the memory, to: retrieve the intermediate battery temperature from the memory unit; retrieve a current ambient temperature from a temperature sensor mounted near a battery; and ascertain whether the current ambient battery temperature varies from the ambient temperature of the fixed time before present. Based on affirmative ascertainment, an estimating unit coupled to the processing unit is to: determine a temperature gradient value (M2) based on an increase or decrease of the current ambient battery temperature with respect to the ambient battery temperature of the fixed time before present; determine an engine coolant temperature coefficient (K4); determine a fan operating value (M3) corresponding to an operating status of a radiator fan; and estimate a battery temperature based on the intermediate battery temperature, temperature gradient value (M2), the engine coolant temperature (K4) and a fan operating value (M3).

[0015] In an aspect, the present disclosure provides the system in which the temperature gradient value (M2), the engine coolant temperature (K4), and the fan operating value (M3) are determined by respective predefined maps.
[0016] In an aspect, the present disclosure provides the system in which the temperature gradient value (M2) is determined along with the fan operating value (M3) to determine the impact of transition on the battery temperature.
[0017] In an aspect, the present disclosure provides the system in which the processing unit is to retrieve a coefficient of vehicle speed (K1) from a vehicle speed sensor; retrieve the ambient temperature from the temperature sensor mounted near the battery; estimate the intermediate battery temperature based on the ambient temperature, the coefficient of vehicle speed (K1), and the battery internal temperature; and store the intermediate battery temperature in the memory.
[0018] In an aspect, the present disclosure provides the system in which the coefficient of vehicle speed (K1) received from the vehicle speed sensor is processed to be a coefficient value using a predefined map.
[0019] In an embodiment, the present disclosure provides a method for estimating a battery temperature. The method comprising retrieving, by a processing unit, an intermediate battery temperature from a memory, said intermediate battery temperature is based on an ambient temperature and a coefficient of vehicle speed (K1),; retrieving, by the processing unit, a current ambient temperature from an ambient temperature sensor mounted near a battery; ascertaining, by the processing unit, whether the current ambient battery temperature varies from the ambient temperature of the fixed time before present; based on affirmative ascertainment, determining a temperature gradient value (M2) by an estimating unit based on increase or decrease of the current ambient battery temperature with respect to the ambient battery temperature of the fixed time before present; determining an engine coolant temperature (K4) by the estimating unit; determining, by the estimating unit, a fan operating value (M3) corresponding to an operating

status of a radiator fan; and estimating, by the estimating unit, a battery temperature based on the intermediate battery temperature, the temperature gradient value (M2), the engine coolant temperature (K4) and the fan operating value (M3).
[0020] In an aspect, the present disclosure provides the method in which the temperature gradient value (M2), the engine coolant temperature coefficient (K4), and the fan operating value (M3) are determined by respective predefined maps.
[0021] In an aspect, the present disclosure provides the method in which the temperature gradient value (M2) is determined along with the fan operating value (M3) to determine the impact of transition on the battery temperature.
[0022] In an aspect, the present disclosure provides the method which includes retrieving of a coefficient of vehicle speed (K1)from a vehicle speed sensor; retrieving the ambient temperature from the temperature sensor mounted near the battery; estimating the intermediate battery temperature based on the ambient temperature and the coefficient of vehicle speed (K1); and storing the intermediate battery temperature in the memory.
[0023] In an aspect, the present disclosure provides the method in which the coefficient of vehicle speed (K1) received from the vehicle speed sensor is processed to a coefficient value using a predefined map.
[0024] Moreover, the system and method proposed herein help in effectively determining the battery temperature. The proposed system effectively calculates the battery temperature by considering the ambient temperature.
[0025] To further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made regarding 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 numerals represent like components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The illustrated embodiments of the subject matter 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 methods that are consistent with the subject matter as claimed herein, wherein:
[0028] FIG. 1 illustrates a block diagram of a proposed vehicular battery estimation system to determine a battery temperature, in accordance with an embodiment of the present disclosure;
[0029] FIGS. 2A-2C illustrate a flow chart that describes the working of a battery temperature estimation system, in accordance with an embodiment of the present disclosure;
[0030] FIG. 3 illustrates a method for estimating a battery temperature, in accordance with an embodiment of the present disclosure; and
[0031] Fig. 4 illustrates a graph that shows the interconnection between the ambient temperature of the battery and the engine room air temperature.
[0032] The figures depict embodiments of the present subject matter for 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

[0033] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to consider all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0034] As used in the description herein and throughout the claims that follow, the meaning of "a," "an," and "the" includes plural reference unless the context dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context dictates otherwise.
[0035] Since the conventional battery estimation system and method that are generally used in the vehicle fails to consider the change in the ambient temperature of the battery while calculating the battery estimation temperature. As a result, there will be great chances of failure of the battery.
[0036] Generally, the existing vehicular battery estimation system in which the electronic control unit (ECU) determines an estimated battery temperature by a system in which the processing unit retrieve a coefficient of vehicle speed (K1) from a vehicle speed sensor;retrieve the battery ambient temperature from the battery ambient temperature sensor mounted near the battery;;estimate the battery temperature based on the ambient temperature, the coefficient of vehicle speed (K1), and the internal battery temperature; and store the intermediate battery temperature in the memory.
[0037] Here, the ECU plays a vital role in effectively retrieving a coefficient of vehicle speed (K1) from a vehicle speed sensor; and the ambient temperature from the ambient temperature sensor that is mounted near the battery; and finally estimating the battery temperature based on the ambient temperature and the coefficient of vehicle speed (K1), and battery internal temperature; and stores the battery temperature in a memory present in the ECU.

[0038] The coefficient of vehicle speed (K1) is received from the vehicle speed sensor and is processed to a coefficient value using a predefined map. However, in the above-mentioned system, there is no consideration of the change in the battery ambient temperature.
[0039] Hence, precisely, the conventional system and method fail to consider the impact of change in battery ambient temperature that leads to high error in the calculation of the battery temperature when the battery ambient temperature is changing.
[0040] Therefore, in order to overcome the drawbacks of the already existing method and system, the present disclosure proposes a system and a method that helps in calculating the estimated battery temperature by considering change in ambient temperature.
[0041] FIG.1 illustrates a block diagram of a proposed vehicular battery estimation system 100 that includes an electronic control unit (ECU) 102, a battery temperature model 104, and a plurality of model inputs 108.
[0042] The ECU 102 receives inputs from a coolant temperature sensor 114, a battery ambient temperature sensor 116, a vehicle speed sensor 112 and a fan control module 118.
[0043] The coolant temperature sensor 114 provides a coolant temperature signal 130 to the ECU 102. The battery ambient temperature sensor 116 provides a battery ambient temperature signal 132 to the ECU 102. The fan control module 118 provides a fan status signal 134 to the ECU 102. The fan status signal 134 also indicates whether the radiator fan 122 is on or off. Here, a radiator fan 122 is placed in proximate to a battery 114 of the vehicle . The vehicle speed sensor 112 provides a coefficient of vehicle speed data to the ECU 102. The coefficient of vehicle speed, is indicative of airflow generated by vehicle movement.
[0044] Those skilled in the art can appreciate that battery temperature is function of heat transfer between battery 124 internal temperature and battery ambient temperature 132. Additionally, the airflow generated by vehicle

movement and the radiator fan 122 also affects the temperature of the battery 124.
[0045] Moreover, the ECU 102 generates the model inputs 108 as per the inputs getting from vehicle speed sensor 112, coolant temperature sensor 114 and battery ambient temperature sensor 116. The battery temperature model 104 estimates an internal temperature estimate 136 of the battery 124 according to the model inputs 108. The model inputs 108 include, but are not limited to, coolant temperature, battery ambient temperature, coefficient of vehicle speed , fan on/off status,. The battery temperature model 104 outputs the internal battery temperature estimate 136 to the ECU 102, which communicates the internal battery temperature estimate 138 to a vehicle charging system 140.
[0046] Alternatively, the battery temperature model 104 may output the internal battery temperature estimate 138 directly to the vehicle charging system 140. The vehicle charging system 140 operates according to the internal battery temperature estimate 138. In particular, the vehicle charging system 140 uses the internal battery temperature estimate 138 to determine an accurate setpoint for an electronic voltage regulator. An accurate setpoint is necessary to prevent the vehicle charging system 140 from overcharging or undercharging the battery 124. At high temperatures, overcharging of the battery 124 is possible. Conversely, undercharging the battery is possible at low temperatures.
[0047] FIGS. 2A-2C clearly illustrates a flow chart of the operation of the proposed vehicular battery estimation system 100. As shown in FIG. 1, the proposed system 100 includes the ECU 102 which may include an interface(s) and a memory 102A. The interface(s) may include a variety of interfaces, for example, interfaces for data input and output devices referred to as I/O devices, storage devices, network devices, and the like. The interface(s) facilitate communication between the ECU 102 and various computing devices connected in a networked environment. The interface(s) may also provide a communication pathway for one or more components of the ECU 102. The

memory 102A may store one or more computer-readable instructions, which may be fetched and executed to set a system state as one of wakeable through atriggerand non-wakeable. The memory 102Amay include any non-transitory computer-readable medium including, for example, volatile memory such as RAM, or non-volatile memory such as EPROM, flash memory, and the like.
[0048] In case of working of the proposed vehicular battery estimation system 100, the memory 102A stores an intermediate battery temperature of the battery 124. The intermediate battery temperature may be a battery temperature calculated by the vehicular battery estimation system in which the processing unit (102b) of the Electronic Control System (ECU) (102) retrieve a coefficient of vehicle speed (K1) from a vehicle speed sensor (112); retrieve the battery ambient temperature from the battery ambient temperature sensor (116) mounted near the battery (124) estimate the battery temperature based on the ambient temperature, the coefficient of vehicle speed (K1), and the internal battery temperature; and store this battery temperature in the memory (102A). This battery temperature is also called as an intermediate battery temperature.
This intermediate battery temperature is calculated by adding the intermediate temperature previous value with the difference between the battery ambient temperature and the intermediate battery temp, previous value, wherein the said calculated difference is multiplied by the factor (K1) before adding with the intermediate temperature previous value.
[0049] The ECU 102 further includes an estimating unit 102C. The processing unit 102B and the estimating unit 102C may be implemented as a combination of hardware and programming (for example, programmable instructions) to implement one or more functionalities of the processing unit 102B and the estimating unit 102C. In the examples described herein, such combinations of hardware and programming maybe implemented in several different ways. For example, the programming for the processing unit 102B and the estimating unit 102C may be processor-executable instructions stored on a non-transitory machine-readable storage medium, and the hardware for

the processing unit 102B and the estimating unit 102C may include a processing resource (for example, one or more processors), to execute such instructions. In the present examples, the machine-readable storage medium may store instructions that, when executed by the processing resource, implement the processing unit 102B and the estimating unit 102C. In such examples, the ECU 102 may include the machine-readable storage medium storing the instructions and the processing resource to execute the instructions, or the machine-readable storage medium may be separate but accessible to the ECU 102 and the processing resource. In other examples, the processing unit 102B and the estimating unit 102C may be implemented by electronic circuitry
[0050] Referring back to FIG. 2A, at step 202, the processing unit 102B determines whether the intermediate battery temperature is computed in the previous cycle or not.
[0051] In case, the intermediate battery temperature is not computed in the previous cycle, the processing unit 102B retrieves the intermediate battery temperature based on a default value (step 204). The default value may or may not be same as the battery ambient temperature.
[0052] In case, the intermediate battery temperature is computed in the previous cycle, the processing unit 102B retrieves the intermediate battery temperature from the memory 102A (Step 206).
[0053] Thereafter, in step 208, the processing unit 102B receives a coefficient of vehicle speed from a vehicle speed sensor. In an aspect, in step 210, the processing unit 102B calculates a coefficient of vehicle speed K1 from the ECU 102 using a pre-defined map.
[0054] At step 212, the processing unit 102B further retrieves a battery ambient temperature from a battery ambient temperature sensor 116 mounted near the battery 124.
[0055] Referring to FIG. 2B, at step 214, the processing unit 102B estimates intermediate battery temperature using the intermediate battery

temperature (the battery ambient temperature, and the coefficient K1 calculated based on vehicle speed).
[0056] Then, at step 216, the processing unit 102B retrieves a current battery ambient temperature from an battery ambient temperature sensor 116 mounted near the battery.
[0057] At step 218, the processing unit 102B ascertains whether the current battery ambient temperature varies from the battery ambient temperature of the fixed time before present.
[0058] At step 220, in case there is no variation between the current battery ambient temperature and the battery ambient temperature of fixed time before present, the processing unit 102B outputs the intermediate temperature as the battery temperature and stores it in the memory 102A.
[0059] Otherwise, at step 222, in case the current battery ambient temperature varies from the battery ambient temperature of the intermediate battery temperature, the estimating unit 102C determines a temperature gradient value M2 based on increase or decrease of the current battery ambient temperature with respect to fixed time before present or one or more previous battery ambient temperature.
[0060] Further, referring to FIG. 2C, at step 224, the estimating unit 102C calculates K4 coefficient from an engine coolant temperature. In an example, the value of the K4 may vary from 90-100 and is function of engine coolant temperature.
[0061] At step 226, the estimating unit 102C determines a fan operating value M3 corresponding to an operating status of the radiator fan 122.
[0062] Then, at step 228, the estimating unit 102C estimates the battery temperature based on the intermediate battery temperature, a temperature gradient value M2, the engine coolant temperature coefficient K4, the fan operating value M3. and the current ambient temperature.

[0063] The estimated battery temperature is calculated by adding the difference between engine coolant temperature coefficient and the battery ambient temperature with the battery intermediate temperature, wherein the said calculated difference is multiplied by two coefficient M2 and M3 before adding with the battery intermediate temperature . Here
M2 = temperature gradient value determined by respective predefined maps;
M3 = fan operating value determined by respective predefined maps; and
K4 = engine coolant temperature coefficient determined by respective predefined map
[0064] At step 230, once the ignition is off, the operation of estimating a battery temperature is terminated.
[0065] Thus, with the help of the method proposed herein, the battery temperature of the vehicle can be estimated for the phase where a previous battery ambient temperature is not equal to a current battery ambient temperature, so as to cover a time phase where the battery ambient temperature is increasing or decreasing. This enables the proposed method to provide an accurate battery temperature in all environmental conditions includiing, increasing battery ambient temperature, decreasing battery ambient temperature, or stable battery ambient temperature.
[0066] FIG. 3 illustrates an example method 300 for estimating a battery temperature. The order in which the method is described is not intended to be construed as a limitation, and any number of the described method blocks may be combined in any order to implement the methods or an alternative method. Furthermore, method 300 may be implemented by processing resource or electronic control unit (ECU) through any suitable hardware, non-transitory machine-readable instructions, or combination thereof.

[0067] At block 302, the method 300 includes retrieving, by a processing unit 102B, the intermediate battery temperature from the memory unit 102A. The intermediate battery temperature is based on an ambient temperature and a coefficient of vehicle speed (Ki),
[0068] At block 304, the method 300 includes retrieving, by the processing unit 102B, a current battery ambient temperature from an battery ambient temperature sensor 116 mounted near a battery 124.
[0069] At block 306, the method 300 includes ascertaining, by the processing unit 102B, whether the current battery ambient temperature varies from the fixed time before present or one or more previous battery ambient temperature of the intermediate battery temperature
[0070] At block 308, the method 300 includes determining a temperature gradient value M2 by an estimating unit 102C based on the increase or decrease of the current battery ambient temperature with respect to the fixed time before present.
[0071] At block 310, the method 300 includes determining an engine coolant temperature coefficient K4 by the estimating unit 102C.
[0072] At block 312, the method 300 includes determining, by estimating unit 102C, a fan operating value M3 corresponding to an operating status of a radiator fan 122.
[0073] At block 314, the method 300 includes estimating, by the estimating unit 102C, a battery temperature based on the intermediate battery temperature, the temperature gradient value M2, the engine coolant temperature coefficient K4 and the fan operating value M3.
[0074] Fig. 4 illustrates a graph that shows the interconnection between an ambient temperature 402 of the battery captured by the battery ambient temperature sensor and an engine room air temperature 404. As per the graph, the ambient temperature 402 of the battery is sensed differently with the increment in the engine room temperature 404. Hence, there is a great

need to take change in the ambient temperature in to consideration while calculating the estimate battery temperature.
[0075] The present disclosure meets the requirement of estimation the battery temperature by taking the change in the ambient temperature of the battery in consideration. Further, the present disclosure describes the system and method that helps in effectively calculating the battery estimation temperature. The system and method proposed in the present disclosure provides better performance and reliable in nature. Further, the additional advantages of the present disclosure are listed hereinbelow.
TECHNICAL ADVANTAGES
[0076] There is a plurality of features which are listed as technical advantages below:
[0077] The present disclosure provides a system and a method that facilitates in effective determination of the battery estimation temperature.
[0078] The present disclosure provides a system and a method that facilitates in effective determination of the battery estimation temperature by taking the change in battery ambient temperature into consideration.
[0079] The present disclosure provides a system and a method that helps in determining the state of readiness of battery at any time.
[0080] These features help to extend the life of the battery. As a result, chances of frequent change of battery is eliminated.
[0081] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various

arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter.
[0082] Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.

We Claim:

1. A system (100) for estimating a battery temperature, said system comprising:
a memory (102A) storing an intermediate battery temperature of a battery (124), said intermediate battery temperature is based on an ambient temperature and a coefficient of vehicle speed (K1);
a processing unit (102B), coupled to the memory (102A), to:
retrieve the intermediate battery temperature from the memory (102A);
retrieve a current ambient temperature from an ambient temperature sensor (116) mounted near the battery (124); and
ascertain whether the current battery ambient temperature varies from the battery ambient temperature of the fixed time before present; and
based on affirmative ascertainment, an estimating unit (102c) coupled to the processing unit (102b) is to:
determine a temperature gradient value (M2) based on increase or decrease of the current battery ambient temperature with respect to the battery ambient temperature of the fixed time before present;
determine an engine coolant temperature coefficient (K4);
determine a fan operating value (M3) corresponding to an operating status of a radiator fan (122); and
estimate a battery temperature based on the intermediate battery temperature, the temperature gradient value (M2), the engine coolant temperature (K4) and the fan operating value (M3).

2. The system (100) as claimed in claim 1, wherein the temperature gradient value (M2), the engine coolant temperature coefficient (K4), and the fan operating value (M3) are determined by respective predefined maps.
3. The system (100) as claimed in claim 1, wherein the temperature gradient value (M2) is determined along with the fan operating value (M3) to determine impact of transition on the battery temperature.
4. The system (100) as claimed in claim 1, wherein the estimated battery temperature is determined by adding the difference between the engine coolant temperature coefficient and the battery ambient temperature with the battery intermediate temperature, wherein the said calculated difference is multiplied by two coefficient M2 and M3 before adding with the battery intermediate temperature .
5. The system (100) as claimed in claim 1, wherein the processing unit (102b) is to:
retrieve a coefficient of vehicle speed (K1) from a vehicle speed sensor (112);
retrieve the battery ambient temperature from the battery ambient temperature sensor (116) mounted near the battery (124);
estimate the intermediate battery temperature based on the ambient temperature, the coefficient of vehicle speed (K1), and the internal battery temperature; and
store the intermediate battery temperature in the memory (102A).

6. The system (100) as claimed in claim 5, wherein the coefficient of vehicle speed (K1) received from the vehicle speed sensor (112) is processed to a coefficient value using a predefined map.
7. The system (100) as claimed in claim 5, wherein the intermediate battery temperature is calculated by adding the intermediate temperature previous value with the difference between the battery ambient temperature and the intermediate battery temp, previous value, wherein the said calculated difference is multiplied by the factor (K1) before adding with the intermediate temperature previous value.
8. A method (300) for estimating a battery temperature, said method comprising:
retrieving, by a processing unit (102B), an intermediate battery temperature from a memory (102A), said intermediate battery temperature is based on an battery ambient temperature, and a coefficient of vehicle speed (K1),;
retrieving, by the processing unit (102B), a current battery ambient temperature from a battery ambient temperature sensor (116) mounted near a battery (124);
ascertaining, by the processing unit (102B), whether the current battery ambient temperature varies from the battery ambient temperature of the fixed time before present;
based on affirmative ascertainment, determining a temperature gradient value (M2) by an estimating unit (102C) based on increase or decrease of the current ambient battery temperature with respect to the ambient battery temperature of the intermediate battery temperature;
determining an engine coolant temperature coefficient (K4) by the estimating unit (102C);

determining, by the estimating unit (102C), a fan operating value (M3) corresponding to an operating status of a radiator fan (122); and
estimating, by the estimating unit (102C), a battery temperature based on the intermediate battery temperature, the temperature gradient value (M2), the engine coolant temperature coefficient(K4) and the fan operating value (M3).
9. The method (300) as claimed in claim 8, wherein the temperature gradient value (M2), the engine coolant temperature coefficient(K4), and the fan operating value (M3) are determined by respective predefined maps.
10. The method (300) as claimed in claim 8, wherein the temperature gradient value (M2) is determined along with the fan operating value (M3) to determine impact of transition on the battery temperature.
11 .The method (300) as claimed in claim 8, wherein the estimated battery temperature is determined by adding the difference between the engine coolant temperature coefficient and the battery ambient temperature with the battery intermediate temperature, wherein the said calculated difference is multiplied by two coefficient M2 and M3 before adding with the battery intermediate temperature .
12. The method (300) as claimed in claim 8, wherein before retrieving the intermediate battery temperature from the memory (102A), the method comprising:
retrieving, by the processing unit (102B), a coefficient of vehicle speed (Ki) from a vehicle speed sensor (112);

retrieving, by the processing unit (102B), the ambient temperature from the ambient temperature sensor (116) mounted near the battery (124);
estimating, by the processing unit (102B), the intermediate battery temperature based on the ambient temperature, the coefficient of vehicle speed (K1), and the battery internal temperature; and
storing, by the processing unit (102B), the intermediate battery temperature in the memory (102A).
13. The method (300) as claimed in claim 12, wherein the coefficient of vehicle speed (K1) received from the vehicle speed sensor (112) is processed to a coefficient value using a predefined map.
14. The method (300) as claimed in claim 12, wherein the intermediate battery temperature is determined by adding the intermediate temperature previous value with the difference between the battery ambient temperature and the intermediate battery temp, previous value, wherein the said calculated difference is multiplied by the factor (K1) before adding with the intermediate temperature previous value.