Waste heat management system of an electric vehicle, method and computer-readable medium

Abstract

Waste heat management system of an electric vehicle, comprising: a pump (100) configured to regulate a flow rate of a coolant through the waste heat management system; an onboard charger coolant line (C) and an engine coolant line (B) branching in parallel from an outlet opening of a pump coolant line (A) of the pump (100); and a heater core coolant line (D) and a radiator coolant line (E), each connected in parallel at a connector to an inlet opening of the pump coolant line (A) and a connector to outlet openings of the onboard charger coolant line (C) and the engine coolant line (B).

Description

BACKGROUND OF THE INVENTION 1. Technical field

[0001] The present invention relates to a system and method for managing waste heat dissipated by an electric vehicle, which can effectively utilize the waste heat generated by an onboard charger (OBC) or an engine of an electric vehicle to heat the electric vehicle, and can improve the fuel efficiency of an electric vehicle by heating an engine using the waste heat generated by the onboard charger (OBC). 2. Description of the state of the art

[0002] The term "electric vehicle" refers to a vehicle that uses electric power as its primary power source, that is, a vehicle equipped with a system for charging a battery with electric power and then supplying the electric power to a motor as a power source. Examples include electric-chargeable vehicles, hybrid vehicles, fuel cell vehicles, and the like.

[0003] From DE 101 53 586 A1, a waste heat management system of an electric vehicle is known, comprising a pump configured to regulate a flow rate of a coolant through the system; an on-board charger coolant line (OBC coolant line) and an engine coolant line branching off in parallel from an outlet opening of a coolant line of the pump; and a heater core coolant line and a radiator coolant line each connected in parallel at a connector to an inlet opening of the coolant line of the pump and a connector to outlet openings of the heater core coolant line and the radiator coolant line.

[0004] WO 2011 / 026 847 A1 discloses a secondary circuit in which a coolant circulates. The secondary circuit consists of: a main line between an output (6) of a first three-way valve and an input of a second three-way valve; a first secondary line between a first output of the second three-way valve and a first input of the first three-way valve; and a second secondary line between a second output of the second three-way valve and a second input of the first three-way valve.

[0005] US 7,789,176 B2 describes an efficient thermal management system using a single heat exchanger. A refrigeration subsystem cools the heat exchanger. A first coolant circuit, in thermal communication with the heat exchanger, is used to cool the energy storage system. A second coolant circuit, corresponding to the HVAC subsystem, is also in thermal communication with the heat exchanger. Preferably, a third coolant circuit, corresponding to the drive motor cooling subsystem, is coupled to the HVAC coolant circuit, thereby providing an efficient means of providing heat to the HVAC subsystem.

[0006] DE 10 2004 041 161 A1 discloses methods and devices for controlling air conditioning in a passenger compartment of a hybrid motor vehicle. The device comprises an internal combustion engine capable of being started and temporarily stopped, an air conditioning compressor, and an electric compressor motor dedicated exclusively to and coupled to drive the air conditioning compressor. Furthermore, sensors are coupled to monitor selected parameters associated with the motor vehicle. An electronic controller is coupled to the internal combustion engine, the compressor motor, and the sensors. When the (internal combustion) engine is running, it operates the compressor to provide air conditioning for the passenger compartment.The controller responds to the selected parameters to selectively drive the compressor motor when the internal combustion engine is temporarily stopped, allowing air conditioning cooling to continue to be delivered to the passenger compartment when certain monitored conditions are met. The controller stops the compressor motor when the internal combustion engine is restarted, and the internal combustion engine then drives the compressor again.

[0007] DE 44 33 836 C1 describes a device for heating the interior of an electric vehicle with an air-cooled high-temperature battery, whose waste heat is used for heating. Heat is supplied to the interior via a fluid circuit with a heat exchanger that can be controlled by the battery's exhaust air and fresh air. This fluid circuit is connected to the heat-generating components of the electric drive and thus also provides cooling.

[0008] Finally, JP H08-22845 A describes keeping a battery warm using a combustion heater without consuming battery power while driving. A combustion heater is a means of heating cooling water by heat exchange with combustion gas and can heat a battery while driving without using battery energy, thus eliminating the need to increase power consumption. Since either the heater, an inverter and main engine, or the heater alone can be selected as the heat source for heating the battery with the opening and closing movement of a first valve, the heat can be used efficiently. Keeping the battery temperature within the correct temperature range can prevent the distance traveled on a single charge from being reduced, even in cold climates or during winter.Because the heater keeps the battery warm while driving, battery consumption can be minimized, which also helps ensure that the distance traveled on a single charge is not reduced. This allows the battery to develop its full potential right from the start.

[0009] An electric vehicle is equipped with an onboard charger (OBC, slow charger) to charge the battery. The onboard charger (OBC) is a device for charging a battery by connecting the battery to a 110V or 220V power grid. Furthermore, such an electric vehicle is equipped with a low-voltage DC-to-DC converter (LDC) so that the battery power can be used to power electronic components within the vehicle. Furthermore, such an electric vehicle is equipped with an inverter and a motor to transmit motive power.

[0010] The OBC, LDC, inverter, and motor of the electric vehicle are all components that generate waste heat. In the electric vehicle, waste heat is generated by the OBC while charging a battery, by the inverter and motor while the electric vehicle is driving, and by the LDC while the electronic components are operating.

[0011] When such means according to the invention are used appropriately, the limitations associated with battery lifetime can be reduced because the overall fuel efficiency of an electric vehicle can be increased by the efficient reuse of this heat, and in particular the fuel efficiency of the electric vehicle can be increased in winter by preheating the inverter or the motor.

[0012] However, the conventional heat exchanger system for an electric vehicle from the state of the art is as in Fig. 1 is arranged such that the waste heat cannot be used because a positive temperature coefficient (PTC) heater 10 and a fan 12 additionally consume electric power to heat the interior of the electric vehicle, and because the engine compartment is equipped with a water pump 20, a low voltage DC to DC converter (LDC) 30, an inverter 40, a motor 50 and an onboard charger (OBC) 60 connected in series, and is cooled by operating a fan 72 while air flows through a radiator 70.

[0013] In addition, although the waste heat generated by the OBC 60 is used in this system, the waste heat escapes from the radiator and is separated and not used to heat the interior of the electric vehicle, and thus the waste heat is not used efficiently.

[0014] The OBC 60 functions to charge a high-voltage battery by boosting the voltage of an AC grid using a transformer, and then converting the grid's AC source to a DC source using a rectifier when the high-voltage battery needs to be charged, in addition to rapidly charging the high-voltage battery while the vehicle is plugged into a charging station. To prevent the OBC 60 from overheating while the high-voltage battery is being charged, the water pump 20, the radiator 70, and the fan 72 are operated so that the temperature of the OBC 60 does not reach a threshold temperature. However, due to the design and structure of this system, unnecessary heat transfer occurs because the OBC 60 is disposed within the circulating circuit to cool the motor 50, the inverter 40, and the like while the electric vehicle is traveling.

[0015] Accordingly, a system and method are needed to compensate for the insufficient performance of the electric vehicle battery by efficiently utilizing the waste heat generated by the OBC 60 and the motor 50. SUMMARY OF REVELATION

[0016] Accordingly, the present invention has been developed to solve the problems described above, and an object of the present invention is to increase the fuel efficiency of an electric vehicle by using waste heat generated from an onboard charger (OBC) and an engine to heat the interior of the electric vehicle and preheat the engine.

[0017] To achieve the above object, an aspect of the present invention provides a waste heat management system of an electric vehicle, comprising: a pump for regulating the flow rate of a coolant; an OBC coolant line and an engine coolant line branched in parallel from an outlet port of a coolant line of the pump; and a heater core coolant line and a radiator coolant line each connected in parallel to a joint of an inlet port of the pump coolant line and a joint of outlet ports of the OBC coolant line and the engine coolant line.

[0018] Here, the OBC coolant line may be provided with an OBC and an LDC connected in series, and the pump coolant line may be provided at an outlet port thereof with an LDC coolant line in parallel with the OBC coolant line and the engine coolant line.

[0019] The outlet port of the pump coolant line may be connected to inlet ports of the OBC coolant line and the engine coolant line through a multi-way valve, and the heater core coolant line and the radiator coolant line may be connected to the connector of the outlet ports of the OBC coolant line and the engine coolant line through a multi-way valve.

[0020] The waste heat management system may further comprise a control unit, e.g., a regulating device. The control unit serves to allow coolant to flow through the OBC coolant line, the engine coolant line, and the heater core coolant line when the battery is charging, and to allow coolant to flow through the engine coolant line and the heater core coolant line when the battery is not charging.

[0021] Another aspect of the present invention provides a method for managing waste heat of an electric vehicle using an OBC coolant line and an engine coolant line branching in parallel from a pump, comprising the steps of: determining a temperature to select either heating or cooling with an air conditioner; and determining whether a battery is being charged when heating is selected, and then flowing coolant through an OBC coolant line, an engine coolant line, and a heater core coolant line while the battery is being charged, and flowing coolant through an engine coolant line and a heater core coolant line when the battery is not being charged.

[0022] Here, the heating step may further include the step of flowing coolant through an OBC coolant line, an engine coolant line, and a heater core coolant line when cooling with an air conditioner is selected.

[0023] In the temperature determination step, heating or cooling with an air conditioner can be selected based on the interior temperature of the electric vehicle or the user's comfort level. In this regard, the desired interior temperature of the electric vehicle or the air conditioner temperature can be set by a user.

[0024] In the heating step when a battery is being charged, the operation of a pump, the operation of a fan adjacent to a heater core, and the discharge of coolant into a radiator coolant line may be performed sequentially in a predetermined program. Furthermore, when a battery is not being charged, the operation of a pump and the discharge of coolant into a radiator coolant line may be performed sequentially in predetermined program commands stored on a computer-readable medium and executed by the control device. The predetermined program commands may be adjusted based on the temperature increase of the coolant.

[0025] In the heating step, the discharging of coolant into a radiator coolant line may be performed in the predetermined program instructions, and then the opening of an air damper and the operation of a fan or another air swirling device adjacent to a radiator may be performed sequentially. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. 1 is a view illustrating a conventional prior art waste heat management system of an electric vehicle; Fig. 2 shows a waste heat management system of an electric vehicle according to an embodiment of the present invention; Fig. 3 shows a view showing a multi-way valve of the Fig. 2 shows the waste heat management system; Fig. Figure 4 shows a flow chart illustrating a method for handling waste heat using the method described in Fig. 2 shows the waste heat management system; Fig. Figure 5 shows a flowchart illustrating a heating control process that takes place while the battery is in the Fig. 4 shown method for handling waste heat; Fig. Figure 6 is a flowchart illustrating a heating control method while the vehicle is in the Fig. 4 shown method for handling waste heat; Fig. Figure 7 is a flowchart illustrating an air conditioning control process while the battery is in the Fig. 4 shown method for handling waste heat; and Fig. Figure 8 is a flowchart illustrating an air conditioning process while the vehicle is in the Fig. 4 shown method for handling waste heat. DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0028] Fig. 2 shows a waste heat management system of an electric vehicle according to an embodiment of the present invention. The waste heat management system includes: a pump (water pump) 100 for regulating the flow rate of the coolant; an on-board charger (OBC) coolant line (C) and an engine coolant line (B) branching in parallel from an outlet port of a pump coolant line (A) of the pump 100; and a heater core coolant line (D) and a radiator coolant line (E), each connected in parallel to a connector of an inlet port of the pump coolant line (A) and a connector of outlet ports of the heater core coolant line (D) and the radiator coolant line (E).

[0029] Specifically, an electric vehicle is largely divided into an interior and an engine compartment. The interior is equipped with a heater core 400, and the engine compartment is equipped with a pump 100, a motor 200, an onboard charger (OBC) 300, and a radiator 500. All components are connected by coolant pipes, and in this way, the waste heat generated from one side can be transferred to the other side. The transfer of waste heat is controlled by a control unit, e.g., a regulator, switching or regulating a pump valve and a multi-port valve accordingly. This allows an electric vehicle to use a heater core instead of a PTC heater and heat the interior and engine compartment of the vehicle using the waste heat generated by an OBC and other components.

[0030] The pump coolant line (A) connected to the pump 100 constitutes a pump coolant line (A), and the pump coolant line (A) is provided at the outlet port thereof with an OBC coolant line (C) and an engine coolant line (B) arranged in parallel to each other.

[0031] The pump coolant line (A) may further be equipped at its outlet with a low-voltage DC-to-DC converter (LDC) coolant line in parallel with the OBC coolant line (C) and the engine coolant line (B). Since the low-voltage DC-to-DC converter (LDC) 320 generates heat when electrical components are operated, it may be connected in series or parallel with the OBC 300. In this embodiment, the LDC 320 is as shown in Fig. 2, connected in series with the OBC 300. Since the times at which the OBC 300 and the LDC 320 generate heat differ from that of the motor 200, which is a drive unit, it is preferred that they be separated from the motor 200 and connected in parallel.

[0032] Furthermore, a heater core coolant line (D) and a radiator coolant line (E) are each connected in parallel to a connector of an inlet port of the pump coolant line (A) and a connector of outlet ports of the OBC coolant line (C) and the engine coolant line (B). That is, as shown in Fig. As shown in Figure 2, the outlet port of each of the heater core coolant line (D) and the radiator coolant line (E) is connected to the inlet port of the pump coolant line (A), and the inlet port of the heater core and the radiator is connected to the joint of the outlet ports of the OBC coolant line (C) and the engine coolant line (B). Thus, the heater core coolant line (D) and the radiator coolant line (E) are completely connected in parallel. Therefore, when it is necessary to transfer the heat generated by these components to the interior or exterior components of an electric vehicle, a coolant line can be selectively formed.

[0033] Meanwhile, the outlet port of the pump coolant line (A) is connected to the inlet ports of the OBC coolant line (C) and the engine coolant line (B) through a multi-way valve 600 (hereinafter referred to as the "first valve"). In this case, the pump coolant line (A) is connected to the OBC coolant line (C) through the first valve to utilize the waste heat generated by the OBC, and the pump coolant line (A) is connected to the engine coolant line (B) through the first valve to utilize the waste heat generated by the engine. The pump coolant line (A) is connected to both the OBC coolant line (C) and the engine coolant line (B) through the first valve to utilize the waste heat generated by both the OBC and the engine, or to transfer the waste heat generated by the OBC to the engine.

[0034] Fig. 3 shows the multi-way valve 600. As in Fig. As shown in Figure 3, the multi-way valve 600 includes: a branch joint connected to the pump coolant line (A), the OBC coolant line (C), and the heater core coolant line (D); an actuator 630 provided with a plurality of through holes or bores; and a drive unit (M) that rotates the actuator 630. Accordingly, the multi-way valve 600 can arbitrarily change the coolant line by rotating the actuator 630.

[0035] Furthermore, the heater core coolant line (D) and the radiator coolant line (E) are connected to the connector of the outlet ports of the OBC coolant line (C) and the engine coolant line (B) through a multi-port valve 700 (hereinafter referred to as the "second valve"). Accordingly, the connector of the outlet ports of the OBC coolant line (C) and the engine coolant line (B) are selectively connected to the heater core coolant line (D) or the radiator coolant line (E) through the second valve, and thus the waste heat can be selectively transferred to the interior or to external components in the engine compartment of the electric vehicle.

[0036] Finally, when an electric vehicle needs to be heated, the waste heat management system may further include a control unit, e.g., a regulating device. The control unit serves to allow coolant to flow through the OBC coolant line (C), the engine coolant line (B), and the heater core coolant line (D) while the battery is being charged, and to allow coolant to flow through the engine coolant line (B) and the heater core coolant line (D) when the battery is not being charged. Furthermore, the control unit serves to determine the flow rate of the coolant by controlling the on-off state or the flow rate of the pump 100 through a mechanical control of the pump depending on the type of pump used, and serves to form a coolant passage in a desired direction by controlling the multi-way valves 600 and 700.

[0037] When an electric vehicle needs to be heated, the control unit serves to use the waste heat generated by the OBC 300 while charging the battery in winter to heat an electric vehicle by flowing coolant through the OBC coolant line (C), the engine coolant line (B), and the heater core coolant line (D), and serves to greatly reduce the initial power consumption of the engine 200 by this waste heat to preheat the engine 200.

[0038] Furthermore, when the interior of the electric vehicle needs to be heated, the control unit is designed to utilize the waste heat generated by the motor 200 when the battery is not being charged to heat the electric vehicle by flowing coolant through the motor coolant line (B) and the heater core coolant line (D). In this case, the coolant does not flow through the OBC 300 and the radiator 500, so that the escape of waste heat can be prevented, thereby maximizing the heating efficiency of the electric vehicle.

[0039] Fig. Figure 4 shows a flow chart illustrating a method for handling waste heat using the method described in Fig. 2. The waste heat management method, which is a waste heat management method of an electric vehicle using an OBC coolant line and an engine coolant line branched in parallel from a pump, includes the steps of: determining a temperature to select from heating or cooling with an air conditioner (S100); and, when heating is selected, determining whether a battery is being charged, and then flowing coolant through an OBC coolant line, an engine coolant line, and a heater core coolant line while the battery is being charged, and flowing coolant through an engine coolant line and a heater core coolant line when the battery is not being charged (S200, S300).

[0040] First, a temperature is determined so that one of heating and cooling with an air conditioner can be selected (S100). Here, heating or cooling with an air conditioner is selected based on the interior temperature of an electric vehicle, the exterior temperature of an electric vehicle, or the air conditioner temperature set by a user. If heating is selected, it is determined whether a battery is being charged (S140). When the battery is being charged, coolant flows through an OBC coolant line, an engine coolant line, and a heater core coolant line. That is, a heating control process is started when the battery is being charged. Further, when an electric vehicle is running, a heating control process is performed (S300).Furthermore, when only electrical components are operated without charging the battery and the electric vehicle is not moving, additional heating control can be performed (S400). This additional heating control method can be implemented in various ways. Typically, this heating control method can only be implemented through heat transfer, which is attributable to dissipation.

[0041] Meanwhile, when air conditioning cooling is selected, coolant flows through an OBC coolant line, an engine coolant line, and a heater core coolant line (S500, S600). This air conditioning method may also include an air conditioning control method during battery charging, an air conditioning control method during driving, and an additional air conditioning control method.

[0042] Fig. Figure 5 shows a flowchart illustrating a heating control process that takes place while the battery is in the Fig. 4. In the heating step (S200, S300), when a battery is charged, the operation of the pump, the operation of a fan adjacent to a heater core, and the discharge of coolant into a radiator coolant line are sequentially performed in a predetermined program executed by a control device. The predetermined program is set based on the temperature increase of the coolant. Further, in the heating step (S200, S300), the discharge of coolant into a radiator coolant line is performed in the predetermined program, and then the opening of an air damper and the operation of a fan or other air swirling device located near a radiator may be further performed sequentially.

[0043] With reference to Fig. 5. When the heater control process starts, the pump is first operated, and then the first valve is opened in two directions to allow coolant to flow into both an OBC and an engine. Furthermore, a second valve is opened only in the direction of a heater core to heat the interior of an electric vehicle (S210).

[0044] Subsequently, when the coolant temperature rises to 60°C or more while battery charging is in progress (S210), a fan is operated near a heater core in the interior of an electric vehicle so that a larger amount of waste heat can be dissipated to the interior of the electric vehicle (S230). Further, when the coolant temperature is 65°C or more (S240), a louver disposed on the exterior of an electric vehicle is opened to dissipate the heat outside the electric vehicle, and the second valve is opened in both directions (S250). Furthermore, since abnormal heating occurs when the coolant temperature is 70°C or more (S260), in order to protect an OBC, a fan or other air swirling device is operated near a radiator to dissipate a larger amount of heat to the exterior of the electric vehicle (S270).

[0045] In this heater control method, the coolant temperature range can be varied within a wide range. Furthermore, during the heater control method, before detecting the coolant temperature, it is checked whether an abnormal temperature of an OBC or LDC is detected, thus making it possible to cope with overheating. Therefore, thermal efficiency can be improved and stability can be ensured while a battery is being charged.

[0046] Fig. Fig. 6 is a flowchart showing a heating control process during driving in the Fig. 4. In the heating step (S200, S300), when it is determined that a battery is not being charged or an engine is running, the operation of a pump and the discharge of coolant into a radiator coolant line are sequentially performed in a predetermined program. The predetermined program may be set based on the temperature rise of the coolant. Further, in the heating step (S200, S300), the discharge of coolant into a radiator coolant line is performed in the predetermined program, and then the opening of an air damper and the operation of a fan or other air swirling device near a radiator may be further performed sequentially.

[0047] With reference to Fig. 6. When heating is required and the engine is running, the pump is first operated, the first valve is opened only in the direction of the engine, and the second valve is opened only in the direction of the heater core to operate a fan located in the interior of an electric vehicle (S310). Consequently, the waste heat generated by the engine during vehicle operation can be transferred to the interior of the electric vehicle without heat leakage.

[0048] Subsequently, once the coolant temperature rises to 65°C or more (S320), an air damper located outside the electric vehicle is opened, and the second valve is opened in two directions to dissipate heat to the outside of the electric vehicle through heat transfer (S330). Consequently, the engine can be maintained within the stable temperature range.

[0049] Subsequently, once the coolant temperature reaches 70°C or higher (S34), a fan or other air-turbulence device is operated near a radiator to dissipate a larger amount of heat (S350). Meanwhile, the temperature of an LDC or an OBC is continuously monitored to determine whether its temperature is at or below a threshold temperature. In this case, if overheating occurs, the first valve is opened in both directions to transfer the waste heat generated by the LDC and OBC to the engine and interior of an electric vehicle, thus heating the interior, and to transfer this waste heat to the exterior of the electric vehicle to dissipate heat (S370).

[0050] Fig. Fig. 7 is a flowchart showing an air conditioning control process when charging the battery in the Fig. 4 shows the method for handling waste heat, and Fig. Fig. 8 is a flowchart showing an air conditioning process when driving in the Fig. 4. In the air conditioning control process during battery charging, first, an air damper is opened, and then the first valve is opened in both directions so that a motor can absorb the waste heat generated by the OBC, and the second valve is opened only in the direction of a radiator to prevent hot air from being introduced into the interior of an electric vehicle (S510).

[0051] Thereafter, once the coolant temperature is 60°C or more, a pump is operated to dissipate heat (S530), and once the coolant temperature is 65°C or more (S540), a fan or other air swirling device near the radiator is operated to dissipate a larger amount of heat to the outside of an electric vehicle (S550).

[0052] In the air conditioning control process during driving, although similar to the air conditioning control process during battery charging, in the initial step (S610), the second valve is opened in both directions to absorb the heat generated by the engine, and also to some extent into the interior of an electric vehicle to improve the engine performance. When the coolant temperature is 60°C or higher (S620), the second valve is opened only in the direction of a radiator to prevent excessively hot air from being introduced into the interior of the electric vehicle (S630). Here, the comfort and air conditioning performance in the interior of an electric vehicle are primarily balanced against the engine performance. Subsequent steps in the air conditioning control process during driving of the electric vehicle are similar to those of the air conditioning control process during battery charging.

[0053] Furthermore, the control of the system of the present invention may be embodied as computer-readable media on a computer-readable medium comprising executable program instructions executed by a processor, controller, or the like. Examples of computer-readable storage media include, but are not limited to, ROM, RAM, compact disc (CD)-ROMs, magnetic tapes, floppy disks, flash drives, smart cards, and optical data storage devices. The computer-readable recording medium may also be distributed in network-connected computer systems so that the computer-readable medium is stored and executed in a distributed manner.

[0054] As described above, according to the system and method for managing waste heat of an electric vehicle, the waste heat generated by an OBC and an engine can be used to heat the interior of the electric vehicle and preheat the engine, thereby increasing the fuel efficiency of the electric vehicle. Furthermore, electric power can be used more efficiently because the waste heat is gradually controlled, and the stability of heat-generating components can be ensured. Furthermore, energy consumption can be reduced in both summer and winter because an air-conditioning process and a heating process are efficiently performed.

[0055] Although the preferred embodiments of the present invention have been described for illustrative purposes, it will be understood by those skilled in the art that many modifications, additions and substitutions are possible without departing from the scope and spirit of the invention as described in the appended claims.

Claims

[1] Waste heat management system of an electric vehicle, comprising: a pump (100) configured to regulate a flow rate of a coolant through the waste heat management system; an onboard charger coolant line (C) and an engine coolant line (B) branching in parallel from an outlet opening of a pump coolant line (A) of the pump (100); and a heater core coolant line (D) and a radiator coolant line (E), each connected in parallel at a connector to an inlet opening of the pump coolant line (A) and a connector to outlet openings of the onboard charger coolant line (C) and the engine coolant line (B). [2] The waste heat management system of claim 1, wherein an onboard charger (OBC) (300) and a low voltage DC-DC converter (LDC) (320) are arranged in series with each other in the onboard charger coolant line (C). [3] A waste heat management system according to claim 1, wherein the pump coolant line (A) is equipped with a low-voltage DC-DC converter coolant line at an outlet port of the pump (100) in parallel with the on-board charger coolant line (C) and the engine coolant line (B). [4] A waste heat management system according to claim 1, wherein the outlet opening of the pump coolant line (A) is connected to inlet openings of the onboard charger coolant line (C) and the engine coolant line (B) through a multi-way valve (600). [5] The waste heat management system according to claim 1, wherein the heater core coolant line (D) and the radiator coolant line (E) are connected to the connector of the outlet ports of the onboard charger coolant line (C) and the engine coolant line (B) through a multi-way valve (700). [6] The waste heat management system according to claim 1, further comprising a control device configured to allow coolant to flow through the onboard charger coolant line (C), the engine coolant line (B), and the heater core coolant line (D) while the battery is being charged, and to allow coolant to flow through the engine coolant line (B) and the heater core coolant line (D) when the battery is not being charged. [7] A method for managing waste heat of an electric vehicle using an onboard charger coolant line (C) and an engine coolant line (B) branching in parallel from a pump (100) according to the waste heat management system of claim 1, comprising steps of: Determining a temperature to select one of heating and cooling with an air conditioner; and Determining whether a battery is being charged when warm-up has been selected, and then flowing coolant through the onboard charger coolant line (C), the engine coolant line (B), and a heater core coolant line (D) while the battery is being charged, and flowing coolant through the engine coolant line (B) and the heater core coolant line (D) while the battery is not being charged. [8] A method for managing waste heat according to claim 7, wherein the heating step further comprises the step of: flowing coolant through the onboard charger coolant line (C), the engine coolant line (B), and the heater core coolant line (D) when cooling with an air conditioner is selected. [9] The waste heat management method according to claim 7, wherein, in the temperature determining step, heating or cooling with an air conditioner is selected based on an interior temperature of the electric vehicle, an exterior temperature of the electric vehicle, or a temperature of the air conditioner set by a user. [10] A waste heat handling method according to claim 7, wherein, in the step of heating when a battery is charged, the operation of a pump (100), the operation of a fan near a heater core, and the discharge of coolant into a radiator coolant line (E) are sequentially performed in a predetermined program. [11] A waste heat handling method according to claim 7, wherein, in the step of heating when a battery is not being charged, operation of a pump (100) and discharge of coolant into a radiator coolant line (E) are sequentially performed in a predetermined program. [12] A method for handling waste heat according to claim 10, wherein the predetermined program is set based on a temperature rise of the coolant. [13] A waste heat handling method according to claim 10, wherein, in the heating step, the discharging of coolant in the radiator coolant line (E) is performed in the predetermined program, and then the opening of an air damper and the operation of an air swirling device near a radiator (500) are sequentially performed. [14] A method for handling waste heat according to claim 13, wherein the air turbulence device is a fan. [15] A non-transitory computer-readable medium comprising executable program instructions executed by a processor according to the method of claim 7, comprising: Program instructions that determine a temperature in an electric vehicle and select one of heating and cooling with an air conditioner; Program instructions that determine whether a battery is being charged when warm-up has been selected, and then control first and second valves (600, 700) such that coolant flows through an onboard charger coolant line (C), an engine coolant line (B), and a heater core coolant line (D) while the battery is being charged, and control the first and second valves (600, 700) such that coolant flows through the engine coolant line (B) and the heater core coolant line (D) while the battery is not being charged.

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