Description:TECHNICAL FIELD
[001] The embodiments herein generally relate to thermal management systems in vehicles and more, particularly to a thermostat valve in the thermal management system of the vehicle. Further, embodiments herein relate to a method of operating the thermostat valve for battery thermal management in an electric vehicle.

BACKGROUND
[002] Generally, a thermostat valve is a device which is used in a thermal management system of a vehicle for regulating operating temperature of a power source across various operating conditions of the vehicle. In vehicles having internal combustion engines, the thermostat valve is used for thermal management of the engine. Whereas, in electric vehicles, a battery thermal management system (BTMS) plays a vital role in the control of the battery behaviour. BTMS includes air cooling system, liquid cooling system, direct refrigerant cooling system, and thermo-electric cooling system as well as heating. These BTMS are analyzed through a trade-off between performance, weight, size, cost, reliability, safety, and energy consumption.
[003] Conventional liquid cooling based BTMS of electric vehicles have two cooling circuits for both battery box and traction control unit (TCU)/motor/ electric power train. As a part of battery thermal management system, battery should operate in between 25°C to 30°C. For cooling the battery box, a chiller has been provided in a battery box cooling circuit and for heating the battery box, hot coolant flows from an electric power train cooling circuit (60° C) to the battery box cooling circuit by combining both the circuits. For combining both the circuits, the liquid based BTMS uses a pair of 3-way electronic solenoid valves (as shown in fig. 1A and fig. 1B) which are controlled by electronic controllers through logics. However, this liquid cooling based BTMS is complex in design and incurs more cost and also involves more number of joints/ connections in the cooling circuits.
[004] Therefore, there exists a need for a thermostat valve in thermal management system of a vehicle, which obviates the aforementioned drawbacks. Further, there exists a method of operating the thermostat valve for battery thermal management in an electric vehicle.

OBJECTS
[005] The principal object of embodiments herein is to provide a thermostat valve in a thermal management system of a vehicle.
[006] Another object of embodiments herein is to provide a method of operating a thermostat valve for battery thermal management in an electric vehicle.
[007] Another object of embodiments herein is to provide the thermostat valve in the battery thermal management system of the electric vehicle, which allows hot coolant flow from an electric power train cooling circuit to battery cooling circuit for heating a battery box during low temperature conditions.
[008] Another object of embodiments herein is to provide the thermostat valve in the battery thermal management system of the electric vehicle, which maintains ideal temperature for battery box to maintain battery life, performance and avoid thermal runaway.
[009] Another object of embodiments herein is to provide to eliminate the usage of flow control electric solenoid valves and electronic controller units in the battery thermal management system of electric vehicle.
[0010] Another object of embodiments herein is to provide to reduce the number of joints/ connections in the cooling circuits of the battery thermal management system of the electric vehicle.
[0011] Another object of embodiments herein is to provide to the thermostat valve in the battery thermal management system of the electric vehicle, which is easy to manufacture, easy to install and is inexpensive.
[0012] Another object of embodiments herein is to provide to the thermostat valve in the battery thermal management system of the electric vehicle, which is durable and reliable.
[0013] These and other objects of embodiments herein will be better appreciated and understood when considered in conjunction with following description and accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF DRAWINGS
[0014] The embodiments are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0015] Fig. 1A illustrates a conventional liquid cooling based battery thermal management system (BTMS) having an independent coolant loop indicating coolant flow in a battery box cooling circuit for cooling battery box of an electric vehicle;
[0016] Fig. 1B illustrates a conventional liquid cooling based battery thermal management system (BTMS) having a combined coolant loop indicating coolant flow between an electric power train cooling circuit and the battery box cooling circuit for heating the battery box;
[0017] Fig. 2A depicts a thermostat valve in a battery thermal management system of an electric vehicle, where the thermostat valve allows coolant flow in the battery box cooling circuit in an independent loop manner, according to embodiments as disclosed herein;
[0018] Fig. 2B depicts the thermostat valve in the battery thermal management system, where the thermostat valve allows coolant flow between the electric power train cooling circuit and the battery box cooling circuit in a combined loop manner, according to embodiments as disclosed herein;
[0019] Fig. 3 depicts an exploded view of the thermostat valve, according to embodiments as disclosed herein;
[0020] Fig. 4 depicts a perspective view of the thermostat valve, according to embodiments as disclosed herein;
[0021] Fig. 5 depicts a sectional view of the thermostat valve in battery box cooling condition, according to embodiments as disclosed herein;
[0022] Fig. 6 depicts a sectional view of the thermostat valve in battery box heating condition, according to embodiments as disclosed herein;
[0023] Fig. 7 depicts a flowchart indicating steps of a method of operating the thermostat valve for battery thermal management in an electric vehicle, according to embodiments as disclosed herein;
[0024] Fig. 7A depicts a flowchart indicating method steps during battery box cooling condition, according to embodiments as disclosed herein; and
[0025] Fig. 7B depicts a flowchart indicating method steps during battery box heating condition, according to embodiments as disclosed herein.

 
DETAILED DESCRIPTION
[0026] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0027] The embodiments herein achieve a thermostat valve in a thermal management system of a vehicle. Further, embodiments herein achieve a method of operating the thermostat valve for battery thermal management in an electric vehicle. Referring now to the drawings Figs. 3 through 7B, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0028] Fig. 3 depicts an exploded view of the thermostat valve (100), according to embodiments as disclosed herein. In an embodiment, the thermostat valve (100) includes a thermostat housing (102), an inner housing (104), a thermostat plunger assembly (106), a first valve (108), a lock ring (109), a first spring (110), a second spring (112) and a second valve assembly (114). For the purpose of this description and ease of understanding, the thermostat valve (100) is explained herein with below reference to battery thermal management in an electric vehicle. However, it is also within the scope of the invention to use/practice the thermostat valve (100) for thermal management of power source (engine or battery) in electric hybrid vehicles or any other vehicles or industrial machines, where thermal management of power source (engine or battery) is required, without otherwise deterring the intended function of the thermostat valve (100) as can be deduced from the description and corresponding drawings.
[0029] The thermostat housing (102) includes an upper thermostat housing ((102Y), (as shown in fig. 4 and fig. 5)) and a lower thermostat housing ((102Z), (as shown in fig. 4 and fig. 5)). The upper thermostat housing (102Y) is fastened onto the lower thermostat housing (102Z) thereby accommodating the inner housing (104), the thermostat plunger assembly (106), the first valve (108), the first spring (110), the second spring (112) and the second valve assembly (114) therein. The upper thermostat housing (102Y) includes a first input channel ((102YF), (as shown in fig. 5 and fig. 6)) and a first output channel ((102YS), (as shown in fig. 5 and fig. 6)), where the first output channel (102YS) is positioned transverse to the first input channel (102YF). The lower thermostat housing (102Z) includes a second input channel ((102ZF), (as shown in fig. 5 and fig. 6)) and a second output channel ((102ZS), (as shown in fig. 5 and fig. 6)), where the second output channel (102ZS) is positioned transverse to the second input channel (102ZF). The thermostat housing (102) defines a first inlet port (102A), a second inlet port (102B), a first outlet port (102C) and a second outlet port ((102D), (as shown in fig. 5 and fig. 6)). The first inlet port (102A) is defined in the first inlet channel (102YF) of the upper thermostat housing (102Y). The second inlet port (102B) is defined in the second inlet channel (102ZF) of the lower thermostat housing (102Z). The first outlet port (102C) is defined in the first outlet channel (102YS) of the upper thermostat housing (102Y). The second outlet port (102D) is defined in the second outlet channel (102ZS) of the lower thermostat housing (102Z).
[0030] The inner housing (104) is disposed inside the thermostat housing (102). The inner housing (104) is mounted to the lower thermostat housing (102Z) through a rubber seal ((103), (as shown in fig. 5)). The inner housing (104) includes a circular shaped body (104BY), a pair of arms (104AR), a spring retainer (104SR), a pair of legs (104LG) and a plunger stopper ((104S) (as shown in fig. 3)). The circular shaped body (104BY) defines a coolant outlet ((104BYC), (as shown in fig. 5)). One end of each arm (104AR) is connected to the circular shaped body (104BY) and another end of the arm (104AR) is connected to the spring retainer (104SR). One end of each leg (104LG) is connected to the circular shaped body (104BY) and another end of the leg (104LG) is connected to the plunger stopper (104S). The spring retainer (104SR) of the inner housing (104) is adapted to retain the second spring (112) therein to facilitate movable loading of the thermostat plunger (106A) into the inner housing (104). The plunger stopper (104S) is adapted to restrict a movement of the thermostat plunger (106A) beyond a predefined position.
[0031] The thermostat plunger assembly (106) includes a thermostat plunger ((106A), (as shown in fig. 4 to fig. 6)), a temperature responsive medium ((106W), (as shown in fig. 5)) and a thermostat plunger valve seat ((106S), (as shown in fig. 5 and fig. 6)). The thermostat plunger (106A) is movably loaded into the inner housing (104) through the second spring (112). The temperature responsive medium (106W) is accommodated inside the thermostat plunger (106A). For the purpose of this description and ease of understanding, the temperature responsive medium (106W) is considered to be wax. The thermostat plunger valve seat (106S) is connected to the thermostat plunger (106A).
[0032] The first valve (108) is adapted to be loaded onto the thermostat plunger (106) through the first spring (110). The lock ring (109) is adapted to secure the first valve (108) onto the thermostat plunger (106A). One end of the first spring (110) is engaged with the thermostat plunger (106A) and another end of the first spring (110) is engaged with the first valve (108). One end of the second spring (112) is engaged with the spring retainer (104SR) of the inner housing (104) and another end of the second spring (112) is engaged with the thermostat plunger (106A).
[0033] The second valve assembly (114) includes a valve connecting member ((114C), (as shown in fig. 3 and fig. 5) and a second valve ((114V), (as shown in fig. 3 to fig. 6)). The valve connecting member (114C) is connected to the thermostat plunger valve seat (106S). The second valve (114V) is connected to the valve connecting member (114C). The second valve (114V) includes a base (114VB) and a stem ((114VS), (as shown in fig. 5)), where one end of the stem (114VS) is connected to the base (114VB) and another end of the stem (114VS) is connected to the valve connecting member (114C). The base (114VB) of the second valve (114V) defines at least one coolant outlet ((114VP), (as shown in fig. 5)).
[0034] Fig. 5 depicts a sectional view of the thermostat valve (100) in battery box cooling condition, according to embodiments as disclosed herein. Fig. 2A depicts a thermostat valve (100) in a battery thermal management system of an electric vehicle, where the thermostat valve (100) allows coolant flow in the battery box cooling circuit (C1) in an independent loop manner, according to embodiments as disclosed herein. The thermostat plunger (106A) is adapted to be moved to a battery box cooling position in which the thermostat valve (100) allows circulation of coolant in a battery box cooling circuit (C1) in response to undergoing by the temperature responsive medium (106W) a phase change from a solid state to a molten state when a temperature of the coolant in the battery box cooling circuit (C1) is above a predefined temperature threshold. The first inlet port (102A) allows coolant flow from the battery box cooling circuit (C1) into the thermostat housing (102), and the coolant flows to the second control valve (114V) via the coolant outlet (104BYC) defined in the inner housing (104), and the coolant flows to the second outlet port (102D) via the coolant outlet (114VP) defined in the second valve (114V), and the coolant is circulated back to the battery box cooling circuit (C1) via the second outlet port (102D) when the thermostat plunger (106A) is in the battery box cooling position. The first valve (108) blocks the first outlet port (102C) thereby restricting coolant flow from the battery box cooling circuit (C1) to an electric power train cooling circuit (C2), and the second valve (114V) blocks the second inlet port (102B) thereby restricting hot coolant flow from the electric power train cooling circuit (C2) to the battery box cooling circuit (C1) when the thermostat plunger (106A) is in the battery box cooling position. The plunger valve seat (106S) of the thermostat plunger (106A) is moved away from the coolant outlet (104BYC) of the inner housing (104) when the thermostat plunger (106A) is in the battery box cooling position.
[0035] Fig. 6 depicts a sectional view of the thermostat valve (100) in battery box heating condition, according to embodiments as disclosed herein. Fig. 2B depicts the thermostat valve (100) in the battery thermal management system, where the thermostat valve (100) allows coolant flow between the electric power train cooling circuit (C2) and the battery box cooling circuit (C1) in a combined loop manner, according to embodiments as disclosed herein. The thermostat plunger (106A) is adapted to be moved to from the battery box cooling position to a battery box heating position in which the thermostat valve (100) allows circulation of hot coolant from the electric power train cooling circuit (C2) to the battery box cooling circuit (C1) in response to undergoing by the temperature responsive medium (106W) a phase change from the molten state to the solid state when the temperature of the coolant in the battery box cooling circuit (C1) is below the predefined temperature threshold. The first inlet port (102A) allows coolant flow from the battery box cooling circuit (C1) into the thermostat housing (102), and the coolant flows from the thermostat housing (102) to the electric power train cooling circuit (C2) through the first outlet port (102C), and hot coolant flows from the electric power train cooling circuit (C2) to the thermostat housing (102) via the second inlet port (102B), and the hot coolant flows to the second outlet port (102D) via the coolant outlet (114VP) defined in the second valve (110), and the hot coolant flows to the battery box cooling circuit (C1) via the second outlet port (102D). The first valve (108) and the second valve (114V) are moved away from the first outlet port (102C) and the second inlet port (102B) respectively when the thermostat plunger (106A) is in the battery box heating position. The thermostat plunger valve seat (106S) blocks the coolant outlet (104BYC) defined in the inner housing (104) thereby restricting coolant flow therethrough when the thermostat plunger (106A) is in the battery box heating position.
[0036] Fig. 7 depicts a flowchart indicating steps of a method (200) of operating the thermostat valve (100) for battery thermal management in an electric vehicle, according to embodiments as disclosed herein. For the purpose of this description and ease of understanding, the method (200) is explained herein below with reference to operating the thermostat valve (100) for battery thermal management in an electric vehicle. However, it is also within the scope of this invention to practice/implement the entire steps of the method (200) in a same manner or in a different manner or with omission of at least one step to the method (200) or with any addition of at least one step to the method (200) for operating the thermostat valve (100) for thermal management of power source (engine or battery) in electric hybrid vehicles or any other vehicles or industrial machines, where thermal management of power source (engine or battery) is required. At step (202), the method (200) includes undergoing (202), by a temperature responsive medium (106W) accommodated inside a thermostat plunger (106A) of the thermostat valve (106), a phase change from a solid state to a molten state when a temperature of the coolant in a battery box cooling circuit (C1) is above a predefined temperature threshold.
[0037] At step (204), the method (200) includes, moving (204) the thermostat plunger (106A) to a battery box cooling position in which the thermostat valve (100) allows circulation of coolant in the battery box cooling circuit (C1) in response to undergoing by the temperature responsive medium (106W), the phase change from the solid state to the molten state.
[0038] At step (206), the method (200) includes, undergoing (206), by the temperature responsive medium (106W) accommodated inside the thermostat plunger (106A), a phase change from the molten state to the solid state when the temperature of the coolant in the battery box cooling circuit (C1) is below the predefined temperature threshold.
[0039] At step (208), the method (200) includes, moving (208) the thermostat plunger (106A) from the battery box cooling position to a battery box heating position in which the thermostat valve (100) allows circulation of hot coolant from an electric power train cooling circuit (C2) to the battery box cooling circuit (C1) in response to undergoing by the temperature responsive medium (106W), the phase change from the molten state to the solid state.
[0040] Fig. 7A depicts a flowchart indicating method steps during battery box cooling condition, according to embodiments as disclosed herein. The method step (204) of moving the thermostat plunger (106A) to the battery box cooling position in which the thermostat valve (100) allows circulation of coolant in the battery box cooling circuit (C1) in response to undergoing by the temperature responsive medium (106W), the phase change from the solid state to the molten state, includes allowing, by a first inlet port (102A) defined in a thermostat housing (102) of the thermostat valve (102), coolant flow from the battery box cooling circuit (C1) into the thermostat housing (102) at method step (204A).
[0041] At step (204B), the method step (204), includes, allowing, by a coolant outlet (104BYC) defined in an inner housing (104) of the thermostat valve (100), coolant flow to a second control valve (114V). At step (204C), the method step (204), includes, allowing, by a coolant outlet (114VP) defined in the second valve (114V), coolant flow to a second outlet port (102D) defined in the thermostat housing (102). At step (204D), the method step (204), includes, allowing, by second outlet port (102D) defined in the thermostat housing (102), coolant flow to the battery box cooling circuit (C1). At step (204E), the method step (204), includes, allowing, by the battery box cooling circuit (C1), coolant flow to the thermostat housing (102) through the first inlet port (102A). Further, the method step (204) includes, blocking, by a first valve (108) of the thermostat valve (102), a first outlet port (102C) defined in the thermostat housing (102) thereby restricting coolant flow from the battery box cooling circuit (C1) to an electric power train cooling circuit (C2) when the thermostat plunger (106A) is in the battery box cooling position. Furthermore, the method step (204) includes, blocking, by the second valve (114V) of the thermostat valve (100), a second inlet port (102B) defined in the thermostat housing (102) thereby restricting hot coolant flow from an electric power train cooling circuit (C2) to the battery box cooling circuit (C1) when the thermostat plunger (106A) is in the battery box cooling position. The method step (204) includes, maintaining a plunger valve seat (106S) of the thermostat plunger (106A) disengaged from the coolant outlet (104BYC) of the inner housing (104) when the thermostat plunger (106A) is in the battery box cooling position.
[0042] Fig. 7B depicts a flowchart indicating method steps during battery box heating condition, according to embodiments as disclosed herein. The method step (208) of moving the thermostat plunger (106A) from the battery box cooling position to a battery box heating position in which the thermostat valve (100) allows circulation of hot coolant from the electric power train cooling circuit (C2) to the battery box cooling circuit (C1) in response to undergoing by the temperature responsive medium (106W), the phase change from the molten state to the solid state, includes, allowing, by the first inlet port (102A) defined in the thermostat housing (102) of the thermostat valve (102), coolant flow from the battery box cooling circuit (C1) into the thermostat housing (102), at method step (208A).
[0043] At step (208B), the method step (208) includes, allowing, by the first outlet port (102C) defined in the thermostat housing (102), coolant flow from the thermostat housing (102) to the electric power train cooling circuit (C2). At step (208C), the method step (208) includes, allowing, by the second inlet port (102B) defined in the thermostat housing (102), hot coolant flow from the electric power train cooling circuit (C2) to the thermostat housing (102). At step (208D), the method step (208) includes, allowing, by a coolant outlet (114VP) defined in the second valve (114V) of the thermostat valve (100), hot coolant flow to a second outlet port (102D) defined in the thermostat housing (102). At step (208E), the method step (208) includes, allowing, by second outlet port (102D) defined in the thermostat housing (102), hot coolant flow to the battery box cooling circuit (C1)
[0044] At step (208F), the method step (208) includes, allowing, by battery box cooling circuit (C1), coolant flow to the thermostat housing (102) through the first inlet port (102A). Further, the method step (208) includes blocking by the thermostat plunger valve seat (106S) of the thermostat plunger (106A), a coolant outlet (104BYC) defined in an inner housing (104) thereby restricting coolant flow therethrough when the thermostat plunger (106A) is in the battery box heating position.
[0045] The technical advantages of the thermostat valve (100) are as follows. The thermostat valve maintains ideal temperature for battery box to maintain battery life, performance and avoid thermal runaway. Eliminating the usage of flow control electric solenoid valves and electronic controller units in the battery thermal management system of electric vehicle. Reducing the number of joints/ connections in the cooling circuits of the battery thermal management system of the electric vehicle. The thermostat valve is easy to manufacture, easy to install and is inexpensive. The thermostat valve is durable and reliable.
[0046] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modifications within the spirit and scope of the embodiments as described herein.
, C , Claims:1. A thermostat valve (100) comprising:
a thermostat housing (102);
an inner housing (104) disposed inside said thermostat housing (102);
a thermostat plunger assembly (106), wherein said thermostat plunger assembly (106) includes a thermostat plunger (106A), a temperature responsive medium (106W) and a thermostat plunger valve seat (106S);
a first valve (108) adapted to be loaded onto said thermostat plunger (106A) through a first spring (110); and
a second valve assembly (114), wherein said second valve assembly (114) includes a valve connecting member (114C) and a second valve (114V), wherein said valve connecting member (114C) is connected to said thermostat plunger valve seat (106S), wherein said second valve (114V) is connected to said valve connecting member (114C).

2. The thermostat valve (100) as claimed in claim 1, wherein said thermostat housing (102) defines a first inlet port (102A), a second inlet port (102B), a first outlet port (102C) and a second outlet port (102D);
said thermostat plunger (106A) is movably loaded into said inner housing (104) through a second spring (112);
said temperature responsive medium (106W) is accommodated inside said thermostat plunger (106A);
said thermostat plunger valve seat (106S) is connected to said thermostat plunger (106A); and
said second valve (114V) includes a base (114VB) and a stem (114VS), where one end of said stem (114VS) is connected to said base (114VB) and another end of said stem (114VS) is connected to said valve connecting member (114C),
wherein
said base (114VB) of said second valve (114V) defines at least one coolant outlet (114VP).
3. The thermostat valve (100) as claimed in claim 2, wherein said thermostat housing (102) includes an upper thermostat housing (102Y) and a lower thermostat housing (102Z), wherein said upper thermostat housing (102Y) is fastened onto said lower thermostat housing (102Z) thereby accommodating said inner housing (104), said thermostat plunger assembly (106), said first valve (108), said first spring (110), said second spring (112) and said second valve assembly (114) therein,
wherein
said upper thermostat housing (102Y) includes a first input channel (102YF) and a first output channel (102YS), wherein said first output channel (102YS) is positioned transverse to said first input channel (102YF);
said lower thermostat housing (102Z) includes a second input channel (102ZF) and a second output channel (102ZS), wherein said second output channel (102ZS) is positioned transverse to said second input channel (102ZF);
said first inlet port (102A) is defined in said first inlet channel (102YF) of said upper thermostat housing (102Y);
said second inlet port (102B) is defined in said second inlet channel (102ZF) of said lower thermostat housing (102Z);
said first outlet port (102C) is defined in said first outlet channel (102YS) of said upper thermostat housing (102Y); and
said second outlet port (102D) is defined in said second outlet channel (102ZS) of said lower thermostat housing (102Z).

4. The thermostat valve (100) as claimed in claim 1, wherein said thermostat valve (100) includes a lock ring (109) adapted to secure said first valve (108) onto said thermostat plunger (106A);
one end of said first spring (110) is engaged with said thermostat plunger (106A) and another end of said first spring (110) is engaged with said first valve (108); and
said temperature responsive medium (106W) is at least wax.

5. The thermostat valve (100) as claimed in claim 3, wherein said inner housing (104) is mounted to said lower thermostat housing (102Z) through a rubber seal (103), wherein said inner housing (104) includes a circular shaped body (104BY), a pair of arms (104AR), a spring retainer (104SR), a pair of legs (104LG) and a plunger stopper (104S), wherein said circular shaped body (104BY) defines a coolant outlet (104BYC), wherein one end of each of said arm (104AR) is connected with said circular shaped body (104BY) and another end of said arm (104AR) is connected to said spring retainer (104SR), wherein one end of each of said leg (104LG) is connected to said circular shaped body (104BY) and another end of said leg (104LG) is connected to said plunger stopper (104S),
wherein
one end of said second spring (112) is engaged with said spring retainer (104SR) of said inner housing (104) and another end of said second spring (112) is engaged with said thermostat plunger (106A).

6. The thermostat valve (100) as claimed in claim 5, wherein said thermostat plunger (106A) is adapted to be moved to a battery box cooling position in which said thermostat valve (100) allows circulation of coolant in a battery box cooling circuit (C1) in response to undergoing by said temperature responsive medium (106W) a phase change from a solid state to a molten state when a temperature of the coolant in the battery box cooling circuit (C1) is above a predefined temperature threshold;
said first inlet port (102A) allows coolant flow from the battery box cooling circuit (C1) into said thermostat housing (102), and said coolant flows to said second control valve (114V) via said coolant outlet (104BYC) defined in said inner housing (104), and said coolant flows to said second outlet port (102D) via said coolant outlet (114VP) defined in said second valve (110), and said coolant is circulated back to the battery box cooling circuit (C1) via said second outlet port (102D) when said thermostat plunger (106A) is in the battery box cooling position;
said first valve (108) blocks said first outlet port (102C) thereby restricting coolant flow from the battery box cooling circuit (C1) to an electric power train cooling circuit (C2), and said second valve (114V) blocks said second inlet port (102B) thereby restricting hot coolant flow from the electric power train cooling circuit (C2) to the battery box cooling circuit (C1) when said thermostat plunger (106A) is in the battery box cooling position; and
said thermostat valve seat (106S) of said plunger thermostat (106) is moved away the coolant outlet (114BYC) of said inner housing (104) when said thermostat plunger (106A) is in the battery box cooling position.

7. The thermostat valve (100) as claimed in claim 6, wherein said thermostat plunger (106A) is adapted to be moved from the battery box cooling position to a battery box heating position in which said thermostat valve (100) allows circulation of hot coolant from the electric power train cooling circuit (C2) to the battery box cooling circuit (C1) in response to undergoing by said temperature responsive medium (106W) a phase change from the molten state to the solid state when the temperature of the coolant in the battery box cooling circuit (C1) is below the predefined temperature threshold;
said first inlet port (102A) allows coolant flow from the battery box cooling circuit (C1) into said thermostat housing (102), and said coolant flows from said thermostat housing (102) to the electric power train cooling circuit (C2) through said first outlet port (102C), and hot coolant flows from the electric power train cooling circuit (C2) to said thermostat housing (102) via said second inlet port (102B), and said hot coolant flows to said second outlet port (102D) via said coolant outlet (114VP) defined in said second valve (114V), and said hot coolant flows to the battery box cooling circuit (C1) via said second outlet port (102D);
said thermostat plunger valve seat (106S) blocks said coolant outlet (104BYC) defined in said inner housing (104) thereby restricting coolant flow therethrough when said thermostat plunger (106A) is in the battery box heating position; and
said first valve (108) and said second valve (114V) are moved away from said first outlet port (102C) and said second inlet port (102B) respectively when said thermostat plunger (106A) is in the battery box heating position.

8. A method (200) of operating a thermostat valve (100) for battery thermal management in a vehicle, said method (200) comprising:
undergoing (202), by a temperature responsive medium (106W) accommodated inside a thermostat plunger (106A) of the thermostat valve (106), a phase change from a solid state to a molten state when a temperature of the coolant in a battery box cooling circuit (C1) is above a predefined temperature threshold;
moving (204) the thermostat plunger (106A) to a battery box cooling position in which the thermostat valve (100) allows circulation of coolant in the battery box cooling circuit (C1) in response to undergoing by the temperature responsive medium (106W), the phase change from the solid state to the molten state;
undergoing (206), by the temperature responsive medium (106W) accommodated inside the thermostat plunger (106A), a phase change from the molten state to the solid state when the temperature of the coolant in the battery box cooling circuit (C1) is below the predefined temperature threshold; and
moving (208) the thermostat plunger (106A) from the battery box cooling position to a battery box heating position in which the thermostat valve (100) allows circulation of hot coolant from an electric power train cooling circuit (C2) to the battery box cooling circuit (C1) in response to undergoing by the temperature responsive medium (106W), the phase change from the molten state to the solid state.

9. The method (200) as claimed in claim 8, wherein said moving (204) the thermostat plunger (106A) to the battery box cooling position in which the thermostat valve (100) allows circulation of coolant in the battery box cooling circuit (C1) in response to undergoing by the temperature responsive medium (106W), the phase change from the solid state to the molten state, includes,
allowing (204A), by a first inlet port (102A) defined in a thermostat housing (102) of the thermostat valve (102), coolant flow from the battery box cooling circuit (C1) into the thermostat housing (102);
allowing (204B), by a coolant outlet (104BYC) defined in an inner housing (104) of the thermostat valve (100), coolant flow to a second control valve (114V);
allowing (204C), by a coolant outlet (114VP) defined in the second valve (114V), coolant flow to a second outlet port (102D) defined in the thermostat housing (102);
allowing (204D, by second outlet port (102D) defined in the thermostat housing (102), coolant flow to the battery box cooling circuit (C1);
allowing (204E), by the battery box cooling circuit (C1), coolant flow to the thermostat housing (102) through the first inlet port (102A);
blocking, by a first valve (108) of the thermostat valve (102), the first outlet port (102C) defined in the thermostat housing (102) thereby restricting coolant flow from the battery box cooling circuit (C1) to an electric power train cooling circuit (C2) when the thermostat plunger (106A) is in the battery box cooling position, and
blocking, by the second valve (114V) of the thermostat valve (100), a second inlet port (102B) defined in the thermostat housing (102) thereby restricting hot coolant flow from an electric power train cooling circuit (C2) to the battery box cooling circuit (C1) when the thermostat plunger (106A) is in the battery box cooling position.
10. The method (200) as claimed in claim 8, wherein said moving (208) the thermostat plunger (106A) from the battery box cooling position to the battery box heating position in which the thermostat valve (100) allows circulation of hot coolant from the electric power train cooling circuit (C2) to the battery box cooling circuit (C1) in response to undergoing by the temperature responsive medium (106W), the phase change from the molten state to the solid state, includes,
allowing (208A), by the first inlet port (102A) defined in the thermostat housing (102) of the thermostat valve (102), coolant flow from the battery box cooling circuit (C1) into the thermostat housing (102);
allowing (208B), by the first outlet port (102C) defined in the thermostat housing (102), coolant flow from the thermostat housing (102) to the electric power train cooling circuit (C2),
allowing (208C), by the second inlet port (102B) defined in the thermostat housing (102), hot coolant flow from the electric power train cooling circuit (C2) to the thermostat housing (102),
allowing (208D), by a coolant outlet (114VP) defined in a second valve (114V) of the thermostat valve (100), hot coolant flow to a second outlet port (102D) defined in the thermostat housing (102);
allowing (208E), by second outlet port (102D) defined in the thermostat housing (102), hot coolant flow to the battery box cooling circuit (C1);
allowing (208F), by battery box cooling circuit (C1), coolant flow to the thermostat housing (102) through the first inlet port (102A);
blocking by the thermostat plunger valve seat (106S), the coolant outlet (104BYC) defined in the inner housing (104) thereby restricting coolant flow therethrough when the thermostat plunger (106A) is in the battery box heating position.