DESC:FIELD
The present disclosure relates to the field of heat recovery systems.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
The use of heating, ventilation, and air conditioning (HVAC) units has now become an essential feature in most of the modern day automobiles. Typically, the HVAC unit is used for providing conditioned air in the cabin.
Conventionally, an internal combustion engine of the automobile is configured to power to the HVAC unit. However, in case of an electric vehicle (EV) the only source of power to the HVAC unit is from a battery pack that is also used for supplying power to various modules and units of the vehicle. As the driving range of the EV completely depends upon the charge of the battery pack, the driving range of the EV reduces significantly owing to the usage of various modules and units. Additionally, the driving range of the electric vehicle is affected severely when the HVAC unit runs in heating mode.
Conventionally, various control strategies have been employed to optimize the electric power usage so as to increase the efficiency of individual module/units. However, the efficiency cannot be increased beyond a certain limit. Additionally, it is also observed that heat is continuously generated from the battery pack as the battery pack continuously supplies power to various modules/units irrespective of the state of the vehicle, i.e., whether the EV is in charging mode, driving mode, or standstill. This generated heat energy is wasted as it is being dissipated to the ambient air, which is not desired.
Therefore, there is felt a need of a waste heat recovey system that alleviates the aforementioned drawbacks.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
The object of the present disclosure is to provide a waste heat recovery system.
Another object of the present disclosure is to provide a waste heat recovery system that utilizes waste heat generated by a battery pack of an electric vehicle for heating the vehicle’s cabin.
Still another object of the present dislcosure is to provide a waste heat recovery system that minimizes the usage of an electric heater of an HVAC unit.
Yet another object of the present disclosure is to reduce the power required for operating the electric heater of the HVAC unit for heating the cabin.
Still another object of the present dislcosure is to improve the driving reach of the electric vehicle.
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 heat management system for a battery-driven electric vehicle. The heat management system comprises a first fluid circuit, a heat storage device and a second fluid circuit. The first fluid circuit is configured to extract heat from the battery in its operative configuration. The heat storage device is configured to store heat extracted from the first fluid circuit. The second fluid circuit is coupled to the heat storage device for utilizing the stored heat for heating the cabin of the vehicle.
In an embodiment, the first fluid circuit of the battery cooling system comprises a heat-exchanging jacket surrounding the battery, a radiator and a first pumping device. The radiator is configured to discharge heat of the fluid flowing therethrough to the surroundings thereof. The first pumping device is configured to pump a fluid through the second circuit. The second fluid circuit comprises an electric heater, a heater core and a second pumping device. The electric heater is configured to be powered by the battery for heating the fluid flowing therethrough. The heater core is configured to discharge heat of the fluid flowing therethrough in the cabin of the vehicle. The second pumping device is configured to pump a fluid through the first circuit.
In an embodiment, the heat management system comprises four control valves. A first control valve is diposed between the inlet of the electric heater and the outlet of the heat storage device. A second control valve is diposed between the outlet of the first pumping device and the inlet of the heat storage device. A third control valve is diposed between the outlet of the heat-exchanging jacket and the inlet of the heat storage device. A fourth control valve is diposed between the outlet of the heat storage device and the inlet of the radiator.
In an embodiment, the heat management system comprises a first bypass channel configured to bypass flow of the fluid through the heat storage device. The heat management system also comprises a second bypass channel the configured to bypass flow of the fluid through the radiator.
The heat management system comprises a first temperature sensor, a second temperature sensor and a control unit. The first temperature sensor is configured to sense temperature within the heat storage device and to generate a corresponding first temperature signal. The second temperature sensor is configured to sense temperature of the fluid exiting the heat storage device and to generate a corresponding second temperature signal. The control unit is configured to receive the first temperature signal and the second temperature signal and to send switching signals to the control valves, based on magnitudes of the temperature signals.
The control unit is configured to control the control valves and selectively operate the system in at least one of:
a) a cabin heating mode with the electric heater;
b) a battery cooling mode without the heat storage device;
c) a battery cooling mode with the heat storage device; and
d) a cabin heating mode with the electric heater and the heat storage device.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The heat management system for an electric vehicle, of the present disclosure, will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a block diagram of a conventional battery cooling circuit used in electric vehicles;
Figure 2 illustrates a block diagram of a conventional cabin heating circuit used in electric vehicles;
Figure 3 depicts a block diagram of a heat management system, according to an embodiment of the present disclosure.
The diagrams herein are only for illustration purpose and the scope of the disclosure should not be limited by the same.

LIST OF REFERENCE NUMERALS
10 – battery
20 – radiator
25 – cooling fan
30 – first pumping device
40 – first degassing tank
50 – electric heater
60 – heater core
70 – second pumping device
80 – second degassing tank
100 – battery cooling circuit
200 – cabin heating circuit
300 – heat management system
305 – first control valve
310 – second control valve
315 – third control valve
320 – fourth control valve
330 – heat storage device
340 – first temperature sensor
345 – second temperature sensor
350 – first bypass channel
355 – second bypass channel

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, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, elements, components, and/or groups thereof.
When an element is referred to as being “mounted on”, “engaged to”, “connected to” or “coupled to” another element, it may be directly on, engaged, 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, component, region, layer or section from another component, region, layer or section. 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.
Terms such as “inner,” “outer,” “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
Figure 1 illustrates a conventional battery cooling circuit (100) in electric vehicles. The battery cooling circuit (100) consists of a first pump (30), a radiator (20), a cooling fan (25), a first degassing tank (40) and a coolant fluid circulated therethrough. The coolant is circulated in a heat-exchanging jacket surrounding the battery pack (10), through the radiator (20) and through the degassing tank (40) by the first pump (30). The heat generated from the battery pack (10) during charging or discharging is absorbed by the coolant fluid which further flows through the radiator (20), which is mounted in front of the cooling fan (25), where the heat absorbed by the coolant fluid is dissipated into ambient air. Heat dissipation is enhanced by the cooling fan (25). The first pump (30) and cooling fan (25) also consume power from the battery pack (10).
Referring to Figure 2, a conventional cabin heating circuit (200) of an electric vehicle includes an electric heater (50), a heater core (60), a second pump (70) and a second degassing tank (80). Typically, a fluid is circulated through the electric heater (50) by the second pump (70). The fluid is configured to absorb the heat generated by the electric heater (50) and subsequently pass through the heater core (60) for heating the cabin air. The battery pack (10) is configured to supply power to the electric heater (50) for heating the fluid flowing therethrough. However, during winter, the usage of the cabin heating circuit (200) is considerably high, resulting in heavy consumption of power which affects the driving range of the electric vehicle.
The present disclosure envisages a heat management system for electric vehicles. The heat management system seeks to recover heat from a battery pack for various purposes, including heating of the cabin.
Figure 3 illustrates the proposed heat management system (300) in which the first fluid circuit (100) of Figure 1 for battery cooling and the second fluid circuit (200) of Figure 2 for cabin heating are integrated with the heat storage device (330), wherein, the heat storage device (330) is configured to store the heat extracted from the battery pack (10) by the first fluid circuit (100) and the second fluid circuit (200) is configured to utilize the heat stored in the heat storage device (330) for heating the cabin of the vehicle. An embodiment of the heat management system (300) of the present disclosure, as shown in Figure 3, comprises: a battery pack (10), a radiator (20), a cooling fan (25), a first pumping device (30) {hereinafter referred to as ‘first pump (30)’}, a first degassing tank (40), an electric heater (50), a heater core (60), a second pumping device (70) {hereinafter referred to as ‘second pump (70)’}, a second degassing tank (80), a first control valve (305), a second control valve (310), a third control valve (315), a fourth control valve (320), a heat storage device (330), a first temperature sensor (340), a first temperature sensor (345), and a control unit (not shown in Fig.). A heat-exchanging jacket (not shown in figs.) surrounding the battery pack (10), the radiator (20), the first pump (30) and the first degassing tank (40) form the battery cooling circuit (100). The electric heater (50), the heater core (60), the second pump (70) and the second degassing tank (80) form the cabin heating circuit (200). The first control valve (305) and the second control valve (310) couple the cabin heating circuit (200) with the battery cooling circuit (100). The third control valve (315) acts as a bypass valve for the heat storage device (330). The fourth control valve (320) acts as a bypass valve for the radiator (20). The first temperature sensor (340) senses temperature within the heat storage device (330). The second temperature sensor (345) senses temperature of the fluid exiting the heat storage device (330). The control unit is configured to receive first and second temperature signals from the temperature sensors (340, 345) as well as to send switching signals to the control valves (305, 310, 315, 320). The radiator (20), the fan (25), pumps (30, 70), the electric heater (50), the heater core (60) and the degassing tanks (40, 80) are configured to perform their conventional functions. The battery pack (10) is configured to supply power to the pumps (30, 70) and the electric heater (50), apart from supplying power to drive the EV.
The heat management system (300) of the present disclosure is operable in at least one of four modes which include: (a) a cabin heating mode with the electric heater (50); (b) a battery cooling mode without the heat storage device (330); (c) a battery cooling mode with the heat storage device (330); and (d) a cabin heating mode with the electric heater (50) and the heater storage device (120). The control unit selectively operates the valves (305, 310, 315, 320) for changing the mode of operation of the system (300).
When the cabin heating mode with heater (50) is operated by the control unit, the fluid in the circuit of the cabin heating circuit (200) is pumped by the second pump (70) through the electric heater (50), where the fluid absorbs heat, which is further carried to the heater core (60) where the absorbed heat is transferred to the cabin air through a suitable heat exchange mechanism/device (not shown in Fig.). The electric heater (50) is selected from the group consisting of a resistance type heater, inductance type heater and any type of heater using electrical energy from the battery pack (10) to generate heat. The cabin heating mode with heater (50) activated may be operated manually or automatically in cold atmospheric conditions.
When the battery cooling mode without the heat storage device (330) is operated by the control unit, the fluid in the circuit of the battery cooling circuit (100) is pumped by the first pump (30) through the battery pack (10), where the fluid absorbs the heat generated in the battery pack (10), passes through third control valve (315) which directs the fluid via a first bypass channel (350) to bypass the heat storage device (330). Further, the fluid in the circuit (100) passes through the radiator (20) cooled by the cooling fan (25) via the fourth control valve (320) to dissipate the heat absorbed from the battery pack (10) to the ambient air. The battery cooling circuit (100) without the heat storage device (330) is in operation when either the heat storage device (330) is fully charged or the heat storage device (330) is intentionally kept out of use or for any other technical/logical reasons.
When the battery cooling mode with the heat storage device (330) is operated by the control unit, the fluid in the circuit (100) is pumped by the first pump (30) through the battery pack (10), where the fluid absorbs the heat generated in the battery pack (10). Further, the fluid passes through the heat storage device (330) via the third control valve (315), where the heat absorbed from the battery pack (10) is transferred to the heat storage device (330). Further the fourth control valve (320) is controlled to direct the fluid via a second bypass channel (355) to bypass the radiator (20), the fluid the passes through the first degassing tank (40). The heat energy is stored in the heat storage device (330) through a suitable mechanism which comprises a phase change material or any other suitable technology. Heat is transferred from the fluid to the heat storage device (330) by using suitable heat exchange means. The heat exchange means is designed in a configuration selected from amongst various conventionally known configurations. The first temperature sensor (340) fitted in the heat storage device (330) is configured to sense whether the device has reached its full storage capacity. Once the storage device attains its full storage capacity, the first temperature sensor (340) generates a signal for the third control valve (315), which thereby directs the fluid via the first bypass channel (350) to bypass the heat storage device (330). When the heat storage device (330) is bypassed, the fourth control valve (320) directs the fluid through the radiator (20) cooled by the cooling fan (25), where the coolant fluid dissipates the heat absorbed from the battery pack (10) to ambient air. The fluid is further recirculated through the second degassing tank (90).
When the cabin heating mode with the electric heater (50) and the heater storage device (330) is operated by the control unit, the third control valve (315) directs the fluid pumped by the first pump (30) through the heat storage device (330), where the fluid absorbs the heat stored in the heat storage device (330), and further passes through the electric heater (50) through the first control valve (305). In the electric heater (50), the fluid further absorbs little or no heat as per the cabin heating load requirement. The fluid further passes through the heater core (60), where the fluid exchanges heat with the cabin air via a suitable heat exchange device/mechanism (not shown in Figs.). The fluid is then recirculated by the second pump (70) through the second degassing tank (80).
Once the heat storage device (330) is charged, it is available to be used for supplying heat to the heater core (60) in the operation of the cabin heating mode. Here, the fluid is pumped by the first pump (30) to circulate the fluid through the heat storage device (330), where the fluid absorbs heat from the heat storage device (330). The absorbed heat is carried by the fluid to the electric heater (50) where it may absorb some more heat if needed. The fluid from electric heater (50) further passes through the heater core (60), where the air to be blown into the cabin exchanges heat with the fluid and gets heated. The heated air is then blown into the cabin with a suitable blower or centrifugal fan.
The phase change material used in the heat storage device (330) is selected from a group of materials available in the market which comprises: sodium phosphate dibasic dodecahydrate (Na2HPO412H2O), paraffin waxes and blends and the like.
Cabin temperature of 20-25oC is achieved by the proposed system (300) depending upon various operational parameters, which include the size of the heat storage device, cabin size, number of passengers, ambient temperature and the like.
In an embodiment, the control unit is implemented as one or more microprocessors, microcomputers, central processing units, programmable logic controllers, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions.
The heat storage device (330) operatively combines operation of the battery cooling circuit (100) and the cabin heating cicuit (200) according to the mode of the operation. Various operational modes as described above can be in operation individually or simultaneously with any other flow circuit. In an embodiment, the battery cooling mode, heat storage device charging mode and cabin heating mode is operated simultaneously.
In an embodiment, the liquid circulated through the heat management system is a mixture of ethylene glycol and water mixed in a predetermined proportion.
By providing for utilization of the heat extracted from the battery pack for heating the cabin of the EV, the heat management system of the present disclosure extends the drivable range of the EV, while also enhancing overall power conversion efficiency of EV.
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 heat management system, which:
• increases the drivable range of electric vehicles;
• utilizes the waste heat from battery packs;
• reduces the power consumption of the radiator cooling fan;
• reduces load on heater of an HVAC unit; and
• increases battery pack life.
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 are omitted so as to not unnecessarily obscure 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 use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
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.
,CLAIMS:WE CLAIM:
1. A heat management system (300) for a battery-driven electric vehicle, said system (300) comprising:
a. a first fluid circuit (100) for extracting heat from the battery (10) in its operative configuration;
b. heat storage device (330) for storing heat extracted from said first fluid circuit (200);
c. a second fluid circuit (100) coupled to said heat storage device (330) for utilizing the stored heat for heating the cabin of the vehicle.
2. The heat management system (300) as claimed in claim 1, wherein said first fluid circuit (100) comprises:
i. a heat-exchanging jacket surrounding said battery (10);
ii. a radiator (20) configured to discharge heat of the fluid flowing therethrough to the surroundings thereof; and
iii. a first pumping device (30) configured to pump a fluid through said second circuit;
and said second fluid circuit (200) comprises:
i. an electric heater (50) configured to be powered by said battery (10) for heating the fluid flowing therethrough;
ii. a heater core (60) configured to discharge heat of the fluid flowing therethrough in the cabin of the vehicle; and
iii. a second pumping device (70) configured to pump a fluid through said first circuit.
3. The heat management system (300) as claimed in claim 1, wherein said system (300) comprises:
• a first control valve (305) disposed between the inlet of said electric heater (50) and the outlet of said heat storage device (330);
• a second control valve (310) disposed between the outlet of said first pumping device (10) and the inlet of said heat storage device (330);
• a third control valve (315) disposed between the outlet of said heat-exchanging jacket and the inlet of said heat storage device (330); and
• a fourth control valve (320) disposed between the outlet of said heat storage device (330) and the inlet of said radiator (20).
4. The heat management system (300) as claimed in claim 3, wherein said system (300) comprises a first bypass channel (350), one end thereof coupled to said third control valve (315), and said first bypass channel (350) configured to bypass flow of the fluid through said heat storage device (330).
5. The heat management system (300) as claimed in claim 3, wherein said system (300) comprises a second bypass channel (355) one end thereof coupled to said fourth control valve (320), and said second bypass channel (355) configured to bypass flow of the fluid through said radiator (20).
6. The heat management system (300) as claimed in claim 3, wherein said system (300) comprises:
• a first temperature sensor (340) configured to sense temperature within said heat storage device (330) and generate a corresponding first temperature signal;
• a second temperature sensor (345) configured to sense temperature of the fluid exiting the heat storage device (330) and generate a corresponding second temperature signal;
• control unit configured to receive said first temperature signal and said second temperature signal and to send switching signals to the control valves (305, 310, 315, 320), based on magnitudes of said temperature signals.
7. The heat management system (300) as claimed in claim 6, wherein said control unit is configured to switch said control valves (305, 310, 315, 320) and selectively operate said system (300) in at least one of:
a) a cabin heating mode with said electric heater (50);
b) a battery cooling mode without said heat storage device (330);
c) a battery cooling mode with said heat storage device (330); and
d) a cabin heating mode with said electric heater (50) and said heat storage device (330).