Claims:WE CLAIM:
1. A temperature control system (100) for a vehicle battery (114), said system (100) comprising:
a. a coolant loop (10) configured to circulate a coolant through said battery (114) for controlling its temperature, said coolant loop (10) comprising:
i. a chiller unit (108) having a refrigerant line configured to receive a refrigerant from vehicle cabin HVAC system (112), said chiller unit (108) configured to facilitate transfer of heat from said coolant to said refrigerant;
ii. a coolant pump (118) configured to receive said coolant at a reduced temperature from said chiller unit (108), and further configured to pump said coolant through said coolant loop (10);
iii. a battery cooling plate of said battery (114) configured to transport the heat generated by said battery (114) to said pumped coolant;
iv. a coolant directing valve (104) connected to:
1. a radiator branch (40) configured to direct said heated coolant to said chiller unit (108) via a radiator (102), said radiator (102) configured to provide partial cooling of said heated coolant; and
2. a bypass branch (30) configured to direct said heated coolant directly to said chiller unit (108) for facilitating complete removal of heat,
b. a refrigerant loop (20) of said vehicle cabin HVAC system (112), said refrigerant loop (20) connected to said refrigerant line of said chiller unit (108) by means of a refrigerant valve (110);
c. a BMS control unit (106) configured to cooperate with an ambient temperature sensor to receive a sensed ambient temperature value, and further configured to control said coolant directing valve (104), to selectively direct said heated coolant from said battery cooling plate to either of said radiator branch (40) and said bypass branch (30), based on said received ambient temperature value.

2. The system as claimed in claim 1, wherein said coolant loop (10) includes a coolant temperature sensor (120) configured to sense said coolant temperature, and further configured to generate a coolant temperature value.

3. The system as claimed in claim 2, wherein said BMS control unit (106) is configured to cooperate with said coolant temperature sensor (120) to receive said coolant temperature value, and is further configured to facilitate Pulse Width Modulation (PWM) control of said coolant pump (118) based on said coolant temperature value and said ambient temperature value.

4. The system as claimed in claim 1, wherein said coolant directing valve (104) is a three-way solenoid valve.

5. The system as claimed in claim 1, wherein said coolant loop (10) includes a coolant heater (116) configured to heat said coolant upon receiving a heater signal from said BMS control unit (106).

6. The system as claimed in claim 1, wherein said BMS control unit (106) is configured to control said coolant directing valve (104), to direct said coolant to said bypass branch (30), when said sensed ambient temperature value is greater than 25 degree Celsius, in a first mode of operation.

7. The system as claimed in claim 1, wherein said BMS control unit (106) is configured to control said coolant directing valve (104), to direct said coolant to said radiator branch (40), when said sensed ambient temperature value is in the range 0 – 25 degree Celsius, in a second mode of operation.

8. The system as claimed in claim 5, wherein said BMS control unit (106) is configured to generate said heater signal to switch-on said heater (116), when said sensed ambient temperature value falls below 0 degree Celsius, in a third mode of operation.

9. The system as claimed in claim 1, wherein said refrigerant valve (110) is a normally-closed solenoid valve.

10. The system as claimed in claim 7, wherein said BMS control unit (106) is configured to open said refrigerant valve (110), in said second mode of operation, when said radiator (102) is switched on.
, Description:FIELD
The present disclosure relates generally to the field of heating, ventilation and air conditioning (HVAC) systems. More particularly, the present disclosure relates to a thermal management system for battery packs in electric vehicles.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.

Many automotive companies are coming up with the advanced automotive vehicles such as plug-in hybrid electric vehicles to make the environment pollution free. These vehicles are propelled by electric motors and include battery packs for storing the energy required for driving these propulsion motors. The batteries must be heated or cooled to maintain their operating temperature within an adequate range, otherwise they will be compromised due to adverse climatic conditions. Batteries give off heat when electric power is drawn. When a significant amount of energy flows into and out of the battery, the temperature of the battery may rise above a desired level, thereby degrading its performance. So the battery must be cooled in order not to heat up to the temperatures above desirable level. On the other hand, at low ambient temperatures, such as below 0° Celsius, heating of the battery becomes necessary, so that electric power can be drawn from the battery and charging with electric power is possible. Consequently, these vehicles use various techniques for managing the temperature of their battery packs.

A battery consists of several cells and modules connected in series and parallel depending on battery structure. It is essential to maintain a homogeneous temperature throughout the cells and modules of the battery for enhanced performance and life.
Conventional electric vehicles include a coolant circuit for facilitating cooling of batteries. These batteries are particularly cooled by facilitating flow of a coolant through the battery plates. Traditionally, liquid cooled or air-cooled mechanisms are used for battery cooling. However, these cooling techniques result in non-uniform temperature across the battery cells, which is not desired.

Other conventional battery temperature management systems rely on air flow from the vehicle HVAC system. In these systems, the passenger cabin air is directed through the battery pack. But these systems suffer from drawbacks such as vibration due to battery blower motor, low heat rejection, limited battery cooling capacity at the beginning of drive cycle after the vehicle has been parked in the sun, and accidental blockage of cooling air inlet by passengers resulting in reduced air flow to the battery.

In addition to this, it is sometimes desirable to control the temperature of the cabin while managing the temperature of battery, and vice versa. The prevailing systems use a separate supplementary HVAC system specifically for heating and cooling the battery. This increases the cost and weight of the vehicles, which is not desired.

Therefore, there is felt a need to provide a temperature control system for vehicle batteries that eliminates all the above-mentioned drawbacks.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:

It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.

An object of the present disclosure is to provide a temperature control system for a vehicle battery.

Another object of the present disclosure is to provide a temperature control system for a vehicle battery that results in high temperature uniformity within the battery pack.

Still another object of the present disclosure is to provide a temperature control system for a vehicle battery that improves the performance of battery pack.

Yet another object of the present disclosure is to provide a temperature control system for a vehicle battery that increases the battery life.

Still another object of the present disclosure is to provide a temperature control system for a vehicle battery that is accurate.

Yet another object of the present disclosure is to provide a temperature control system for a vehicle battery that maintains optimal battery cell temperature.

Still another object of the present disclosure is to provide a temperature control system for a vehicle battery that reduces the total HVAC power consumption by integrating the vehicle cabin HVAC system with battery temperature management system.

Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure envisages a temperature control system for a vehicle battery. The system comprises a coolant loop, a refrigerant loop, and a BMS control unit. The coolant loop is configured to circulate a coolant through the battery for controlling its temperature. The coolant loop comprises a chiller unit, a coolant pump, a battery cooling plate of the battery, and a coolant directing valve.
The chiller unit includes a refrigerant line configured to receive a refrigerant from the vehicle cabin HVAC system. The chiller unit is configured to facilitate transfer of heat from the coolant to the refrigerant. The coolant pump is configured to receive the coolant at a reduced temperature from the chiller unit, and is further configured to pump the coolant through the coolant loop. The battery cooling plate is configured to transport the heat generated by the battery to the pumped coolant. The coolant directing valve is located after the battery, and is connected to a radiator branch and a bypass branch. The radiator branch is configured to direct the heated coolant to the chiller unit via a radiator. The radiator is configured to provide partial cooling of the heated coolant. The bypass branch is configured to direct the heated coolant directly to the chiller unit for facilitating complete removal of heat. The refrigerant loop of the vehicle cabin HVAC system is connected to the refrigerant line of the chiller unit by means of a refrigerant valve. The BMS control unit is configured to cooperate with an ambient temperature sensor to receive sensed ambient temperature value, and is further configured to control the coolant directing valve, to selectively direct the heated coolant from the battery cooling plate to either of the radiator branch and the bypass branch, based on the received ambient temperature value.

In an embodiment, the coolant loop includes a coolant temperature sensor configured to sense the coolant temperature, and further configured to generate a coolant temperature value. The BMS control unit is configured to cooperate with the coolant temperature sensor to receive the coolant temperature value, and is further configured to facilitate Pulse Width Modulation (PWM) control of the coolant pump based on the received coolant temperature value and the ambient temperature value.

In an embodiment, the coolant directing valve is a three-way solenoid valve.

In an embodiment, the BMS control unit is configured to control the coolant directing valve, to direct the coolant to the bypass branch, when the sensed ambient temperature value is greater than 25o Celsius, in a first mode of operation.
The BMS control unit is further configured to control the coolant directing valve, to direct the coolant to the radiator branch, when the sensed ambient temperature value is in the range 0 – 25o Celsius, in a second mode of operation.

In another embodiment, the system includes a coolant heater configured to heat the coolant upon receiving a heater signal from the BMS control unit. The BMS control unit is configured to generate the heater signal to switch-on the heater, when the sensed ambient temperature value falls below 0o Celsius, in a third mode of operation.

In an embodiment, the refrigerant valve is a normally-closed solenoid valve. The BMS control unit is configured to open the refrigerant valve, in the second mode of operation, when the radiator is switched on.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
A temperature control system for a vehicle battery of the present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a block diagram of temperature control system for a vehicle battery;
Figure 2 illustrates a block diagram of the system of Figure 1 in first mode of operation;
Figure 3 illustrates a block diagram of the system of Figure 1 in second mode of operation; and
Figure 4 illustrates a block diagram of the system of Figure 1 in third mode of operation.
LIST OF REFERENCE NUMERALS
100 – System
10 – Coolant loop
20 – Refrigerant loop
30 – Bypass branch
40 – Radiator branch
102 – Radiator
104 – Coolant directing valve
106 – BMS control unit
108 – Chiller unit
110 – Refrigerant valve
112 – Vehicle cabin HVAC system
114 – Vehicle battery
116 – Coolant heater
118 – Coolant pump
120 – Coolant temperature sensor
202 – Condenser
204 – First refrigerant pressure sensor
206 – Refrigerant temperature sensor
208 – Refrigerant compressor
210 – Second refrigerant pressure sensor
212 – Front HVAC refrigerant valve
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details, are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, operations, elements, components, and/or groups thereof.
When an element is referred to as being "connected to," or "coupled to" another element, it may be directly connected or coupled to the other element. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element or component from another element or component. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
A temperature control system for a vehicle battery (hereinafter referred as “system 100”) of the present disclosure is now being described with reference to Figure 1 through Figure 4. Referring to Figure 1, the system 100 comprises a coolant loop 10, a refrigerant loop 20, and a BMS control unit 106. The coolant loop 10 is configured to circulate a coolant through the battery 114 for controlling its temperature. The coolant loop 10 comprises a chiller unit 108, a coolant pump 118, a battery cooling plate of the battery 114, and a coolant directing valve 104. The chiller unit 108 includes a refrigerant line configured to receive a refrigerant from the vehicle cabin HVAC system 112. The chiller unit 108 is configured to facilitate transfer of heat from the coolant to the refrigerant. The coolant pump 118 is configured to receive the coolant at a reduced temperature from the chiller unit 108, and is further configured to pump the coolant through the coolant loop 10. The battery cooling plate is configured to transport the heat generated by the battery 114 to the pumped coolant. The coolant directing valve 104 is connected to a radiator branch 40 and a bypass branch 30. The radiator branch 40 is configured to direct the heated coolant to the chiller unit 108 via a radiator 102. The radiator 102 is configured to provide partial cooling of the heated coolant. The bypass branch 30 is configured to direct the heated coolant directly to the chiller unit 108 for facilitating complete removal of heat. The refrigerant loop 20 of the vehicle cabin HVAC system 112 is connected to the refrigerant line of the chiller unit 108 by means of a refrigerant valve 110. In an embodiment, the refrigerant loop 20 consists of a condenser 202 and a refrigerant compressor 208. The refrigerant compressor 208 is electrically driven and may be configured to direct the refrigerant through an evaporator in the vehicle cabin and/or the chiller unit 108 via a condenser 202. The evaporator may be configured to provide cooling to the vehicle cabin. The refrigerant exiting the evaporator is directed through a return line of HVAC system refrigerant loop 20 and back to the compressor 208 to complete the refrigerant loop 20. The refrigerant loop 20 further consists of a first pressure sensor 204, a second pressure sensor 210, and a refrigerant temperature sensor 206. The first pressure sensor 204 is configured to measure the pressure of refrigerant just after the refrigerant exits the condenser 202. The second pressure sensor 210 is configured to measure the pressure of the refrigerant just after the refrigerant exits the evaporator. The measurements of pressure sensors 204, 210 and temperature sensor 206 may be used to control the compressor 208 to ensure appropriate cooling in the vehicle cabin. The refrigerant loop 20 also includes a front HVAC refrigerant valve 212 before the evaporator. As the refrigerant flows through the front HVAC refrigerant valve 212, the pressure and temperature of the compressed and condensed refrigerant is reduced, thereby allowing it to absorb heat from the cabin air blown by the evaporator fins.

In an embodiment, the system 100 includes an ambient temperature sensor configured to sense the ambient temperature, and further configured to generate a corresponding sensed ambient temperature value. The BMS control unit 106 is configured to cooperate with the ambient temperature sensor to receive sensed ambient temperature value, and is further configured to control the coolant directing valve 104, to selectively direct the heated coolant from the battery cooling plate to either of the radiator branch 40 and the bypass branch 30, based on the received ambient temperature value.

In an embodiment, the coolant loop 10 includes a coolant temperature sensor 120 configured to sense the coolant temperature, and further configured to generate a coolant temperature value. The BMS control unit 106 is configured to cooperate with the coolant temperature sensor 120 to receive the coolant temperature value, and is further configured to facilitate Pulse Width Modulation (PWM) control of the coolant pump 118 based on the received coolant temperature value and the ambient temperature value. Thus, the BMS control unit 106 can control the flow of coolant through the battery cooling plate based on the battery requirement. The PWM control of the coolant pump 118 facilitates accurate and sensitive control of coolant flow rate.

In an embodiment, the coolant directing valve 104 is a three-way solenoid valve. The three-way valve is characterized by three ports. The first port is connected to the outlet of battery cooling plate, the second port is connected to the radiator 102, and the third port is connected to the chiller unit 108.

In an embodiment, the BMS control unit 106 is configured to control the coolant directing valve 104, to direct the coolant to the bypass branch 30, when the sensed ambient temperature value is greater than 25o Celsius, in a first mode of operation as shown in Figure 2. The BMS control unit 106 is further configured to control the coolant directing valve 104, to direct the coolant to the radiator branch 40, when the sensed ambient temperature value is in the range 0 – 25o Celsius, in a second mode of operation as shown in Figure 3.

In another embodiment, the system 100 includes a coolant heater 116 configured to heat the coolant upon receiving a heater signal from the BMS control unit 106. The BMS control unit 106 is configured to generate the heater signal to switch-on the heater 116, when the sensed ambient temperature value falls below 0o Celsius, in a third mode of operation as shown in Figure 4.

In an embodiment, the refrigerant valve 110 is a normally-closed solenoid valve. The BMS control unit 106 is configured to open the refrigerant valve 110, in the second mode of operation, when the radiator 102 is switched on. In another embodiment, the refrigerant valve 110 and the coolant directing valve 104 are coupled in such a way that when the coolant directing valve 104 operates in second mode of operation, the refrigerant valve 110 automatically opens. In this mode, the chiller unit 108 acts as a dummy, as no refrigerant passes through the refrigerant line and the coolant is cooled by the radiator 102 alone. In an embodiment, the radiator 102 is a Low Temperature Radiator (LTR).

The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a temperature control system for a vehicle battery that:
• results in high temperature uniformity within the battery pack;
• improves the performance of battery pack;
• increases the battery life;
• is accurate;
• maintains optimal battery cell temperature; and
• reduces the total HVAC power consumption by integrating vehicle cabin HVAC system with battery temperature management system.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments 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.

The foregoing description of the specific embodiments 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 preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.

While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.