System for increasing battery temperature for a vehicle

Abstract

A system for increasing the battery temperature of a vehicle, comprising: an on-vehicle charger having a capacitor and a bidirectional DC converter, the bidirectional DC converter having a first input / output terminal connected to the capacitor and a second input / output terminal connected to the battery and being configured to perform bidirectional power transfer between the first input / output terminal and the second input / output terminal; and a controller that, when battery warming is required, drives the bidirectional DC converter such that the direction of power transfer alternates and supplies an alternating current (AC) having a predetermined frequency to the battery.

Description

Technical Field

[0001] The present disclosure relates to a system for increasing battery temperature, and more particularly, to a system for increasing battery temperature for a vehicle. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] As the problems of global warming and environmental pollution become serious, research and development of eco-friendly vehicles that can minimize environmental pollution as much as possible are actively carried out in the automotive industry, and the market related to eco-friendly vehicles is gradually expanding.

[0004] As eco-friendly vehicles, electric vehicles, hybrid vehicles, and plug-in hybrid vehicles that use an electric motor that generates driving force using electric energy instead of an internal combustion engine that generates driving force by burning existing fossil fuels have been released worldwide. Among eco-friendly vehicles that use electric energy, electric vehicles and plug-in hybrid vehicles receive electric power from an external charging device connected to the power grid to charge a battery provided in the vehicle, and use the power charged in the battery to generate kinetic energy required to drive the vehicle.

[0005] Meanwhile, the impedance of the vehicle's battery increases at low temperatures rather than at room temperature, reducing the charging efficiency, thereby slowing down the charging speed and decreasing the charging amount. To improve the charging performance of the battery at low temperatures, a heating device has been applied to increase the battery temperature by generating heat using a part of the current supplied from the charger to the battery. However, we have found that since the heating device generates heat using the electric power charged in the battery, the heating device reduces the charging energy and should be added to the vehicle separately, resulting in a complex vehicle system and an increase in the unit cost of the vehicle.

[0006] The foregoing is only intended to assist in understanding the background of the present disclosure and is not intended to indicate that the present disclosure falls within the scope of the prior art known to those skilled in the art. Summary of the Invention

[0007] The present disclosure proposes a system for increasing battery temperature for a vehicle, which can induce heat generation by supplying an alternating current to the battery through a bi-directional converter of an on-board charger (OBC), and the on-board charger is provided in the vehicle to charge the battery without a separate heating device, thereby increasing the battery temperature at low temperatures.

[0008] According to one aspect, a system for increasing the temperature of a battery for a vehicle includes: an on-vehicle charger having a capacitor and a bidirectional direct current (DC) converter, the bidirectional DC converter having a first input / output terminal connected to the capacitor and a second input / output terminal connected to the battery and configured to perform bidirectional power transfer between the first input / output terminal and the second input / output terminal; and a controller that, when battery warming is required, drives the bidirectional DC converter such that the direction of power transfer alternates and supplies an alternating current (AC) current having a predetermined frequency to the battery.

[0009] In one form of the present disclosure, the on-vehicle charger may further include: a power factor correction circuit configured to: convert external AC power to direct current (DC) power and apply the DC power to the capacitor in a charging mode in which the external AC power is converted to DC power and supplied to the battery; and when battery warming is required, the controller may not operate the power factor correction circuit.

[0010] In one form of the present disclosure, the predetermined frequency may be determined based on a current frequency in a region where the impedance exhibits a relatively low level compared to the current frequency-impedance characteristic of the battery.

[0011] In one form of the present disclosure, the bidirectional DC converter may include: a transformer; a first switch circuit connected between the first input / output terminal and the primary winding of the transformer and including a plurality of switching elements; and a second switch circuit connected between the second input / output terminal and the secondary winding of the transformer and including a plurality of switching elements.

[0012] In one form of the present disclosure, when battery warming is required, the controller may control the plurality of switching elements of the first switch circuit and the plurality of switching elements of the second switch circuit to alternately switch.

[0013] In one form of the present disclosure, the controller may alternately perform a forward operation and a reverse operation based on the predetermined frequency. In the forward operation, the switching elements of the first switch circuit are turned on or off to supply power from the capacitor to the battery, and in the reverse operation, the switching elements of the second switch circuit are turned on or off to supply power from the battery to the capacitor.

[0014] In another form of the present disclosure, the first switching circuit may be a bridge circuit that includes a first switching element and a second switching element connected in series between a positive terminal and a negative terminal of a first input / output terminal, and a third switching element and a fourth switching element connected in series between the positive terminal and the negative terminal of the first input / output terminal. Specifically, in this bridge circuit, a first connection node between the first switching element and the second switching element is connected to one end of a primary winding of a transformer, and a second connection node between the third switching element and the fourth switching element is connected to the other end of the primary winding of the transformer.

[0015] In another form of the present disclosure, the second switching circuit may be a bridge circuit that includes a fifth switching element and a sixth switching element connected in series between a positive terminal and a negative terminal of a second input / output terminal, and a seventh switching element and an eighth switching element connected in series between the positive terminal and the negative terminal of the second input / output terminal, and in this bridge circuit, a connection node between the fifth switching element and the sixth switching element is connected to one end of a secondary winding of the transformer, and a connection node between the seventh switching element and the eighth switching element is connected to the other end of the secondary winding of the transformer.

[0016] In one form of the present disclosure, the predetermined frequency may be less than the switching frequency of the switching elements of the first switching circuit or the switching frequency of the switching elements of the second switching circuit.

[0017] Other applicable fields will become apparent from the description provided herein. It should be understood that the description and specific examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To better understand the present disclosure, its different forms will now be described by way of example with reference to the accompanying drawings, in which:

[0019] Figure 1 is a block diagram showing a system for increasing battery temperature for a vehicle;

[0020] Figure 2 is a circuit diagram showing a system for increasing battery temperature for a vehicle;

[0021] Figure 3 is a flowchart showing the operation of a system for increasing battery temperature for a vehicle;

[0022] Figure 4 shows a waveform diagram that shows the operation of a switching circuit of a system for increasing battery temperature for a vehicle and the flow of alternating current (AC) according to the operation of its switching circuit; and

[0023] Figure 5It is a graph showing an example of the current frequency-impedance relationship of a battery.

[0024] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. Detailed Description

[0025] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals represent like or corresponding parts and features.

[0026] Hereinafter, systems for increasing the battery temperature for a vehicle according to various forms of the present disclosure will be described in more detail with reference to the accompanying drawings.

[0027] Figure 1 is a block diagram showing a system for increasing the battery temperature for a vehicle according to one form of the present disclosure, and Figure 2 is a circuit diagram showing in more detail a system for increasing the battery temperature for a vehicle according to one form of the present disclosure.

[0028] Referring to Figure 1 and Figure 2 , a system for increasing the battery temperature for a vehicle may include: a battery 10 disposed in the vehicle; an on-board charger (OBC) 30 configured to convert external alternating current (AC) power to generate direct current (DC) charging power for charging the battery 10; and a controller 100 configured to determine whether to control the battery 10 to increase in temperature based on the state of the battery 10, and when the battery 10 needs to increase in temperature, control the OBC 30 to supply an AC current having a predetermined frequency to the battery 10. Specifically, the OBC 30 may include a bidirectional DC converter 37 capable of transmitting power bidirectionally.

[0029] The battery 10 is a component for storing electrical energy, which is supplied to a motor serving as a drive source of the vehicle. Although not shown in the drawings, the terminals of the battery 10 may be connected to an inverter to convert the DC power supplied from the battery 10 into AC power having multiple phases for driving the motor under the control of the inverter and supply the converted electrical power to the motor so that the motor can be driven. The battery 10 disposed in an eco-friendly vehicle may be charged by receiving regenerative energy while the eco-friendly vehicle is being driven, and after the eco-friendly vehicle finishes driving, the battery 10 may be charged by receiving electrical power supplied from an external charging device.

[0030] The OBC 30 may convert the AC power of the external charging device 20 supplied through a charging cable after the vehicle finishes driving into DC power having a voltage capable of charging the battery 10, and supply the converted DC power to the battery 10 to charge the battery 10.

[0031] The on-board charger (OBC) 30 may include: an electromagnetic interference (EMI) filter 31 for removing high-frequency noise components included in the AC power supplied from an external charging device 20; a power factor correction (PFC) circuit 33 for converting the AC power into DC power and adopting the topology of a boost converter circuit to correct the power factor of the input AC power; a capacitor 35 connected to the output terminal of the PFC circuit 33 and configured to form a DC voltage v link ; and a bidirectional DC converter 37 for converting the DC voltage v link formed across the two ends of the capacitor 35 into a DC voltage having a magnitude required for charging the battery 10.

[0032] In one form of the present disclosure, the bidirectional DC converter 37 included in the OBC 30 may include: a first switching circuit 373 having first input / output terminals 371p and 371n connected to the AC power side (i.e., the output terminal of the PFC circuit 33), second input / output terminals 372p and 372n connected to the battery 10, and a plurality of switching elements Q1 to Q4 connected to the first input / output terminals 371p and 371n; and a second switching circuit 375 having a transformer 374 with a primary winding connected to the first switching circuit 373, and a plurality of switching elements Q5 to Q8 connected between the secondary winding of the transformer 374 and the second input / output terminals 372p and 372n.

[0033] Specifically, as Figure 2 shown, the bidirectional DC converter 37 is implemented as an inductor-inductor-capacitor (LLC) resonant converter. When the bidirectional DC converter 37 is implemented as an LLC resonant converter, the bidirectional DC converter 37 may further include a resonant circuit 376 between the first switching circuit 373 and the primary winding of the transformer 374, and the resonant circuit 376 has a resonant capacitor Cr and a resonant inductor Lr, so that a resonant current is generated due to the switching of the plurality of switching elements Q1 to Q4.

[0034] In one form, the bidirectional DC converter 37 is implemented as an LLC resonant converter. Alternatively, a DC converter having a structure including a transformer for insulation (such as a series resonant converter (SRC) topology or a phase-shifted full-bridge topology) and switching circuits provided at two windings of the transformer may be employed as the bidirectional DC converter 37.

[0035] The first switching circuit 373 can be implemented as a bridge circuit, which includes a first switching element Q1 and a second switching element Q2 connected in series between the positive terminal 371p and the negative terminal 371n of the first input / output terminals 371p and 371n, and a third switching element Q3 and a fourth switching element Q4 connected in series between the positive terminal 371p and the negative terminal 371n of the first input / output terminals 371p and 371n. Here, the connection node between the first switching element Q1 and the second switching element Q2 can be connected to one end of the primary winding of the transformer 374, and the connection node between the third switching element Q3 and the fourth switching element Q4 can be connected to the other end of the primary winding of the transformer 374. As Figure 2 shown, in the case of a resonant LLC converter, the connection node between the first switching element Q1 and the second switching element Q2 can be connected to a series connection structure of a resonant inductor Lr and a resonant capacitor Cr that form a resonant circuit 376.

[0036] In addition, the first switching element Q1 to the fourth switching element Q4 can respectively include freewheeling diodes D1 to D4. The anode of the freewheeling diode D1 of the first switching element Q1 can be connected to the connection node between the first switching element Q1 and the second switching element Q2, and the cathode of its freewheeling diode D1 can be connected to the positive terminal 371p of the first input / output terminal. The cathode of the freewheeling diode D2 of the second switching element Q2 can be connected to the connection node between the first switching element Q1 and the second switching element Q2, and the anode of its freewheeling diode D2 can be connected to the negative terminal 371n of the first input / output terminal. Similarly, the anode of the freewheeling diode D3 of the third switching element Q3 can be connected to the connection node between the third switching element Q3 and the fourth switching element Q4, and the cathode of its freewheeling diode D3 can be connected to the positive terminal 371p of the first input / output terminal. The cathode of the freewheeling diode D4 of the fourth switching element Q4 can be connected to the connection node between the third switching element Q3 and the fourth switching element Q4, and the anode of its freewheeling diode D4 can be connected to the negative terminal 371n of the first input / output terminal.

[0037] The second switching circuit 375 can be implemented as a bridge circuit that includes a fifth switching element Q5 and a sixth switching element Q6 connected in series between the positive terminal 372p and the negative terminal 372n of the second input / output terminals 372p and 372n, and a seventh switching element Q7 and an eighth switching element Q8 connected in series between the positive terminal 372p and the negative terminal 372n of the second input / output terminals 372p and 372n. Here, the connection node between the fifth switching element Q5 and the sixth switching element Q6 can be connected to one end of the secondary winding of the transformer 374, and the connection node between the seventh switching element Q7 and the eighth switching element Q8 can be connected to the other end of the secondary winding of the transformer 374.

[0038] Similar to the first switching circuit 373, the fifth switching element Q5 to the eighth switching element Q8 in the second switching circuit 375 can respectively include freewheeling diodes D5 to D8. The anode of the freewheeling diode D5 of the fifth switching element Q5 can be connected to the connection node between the fifth switching element Q5 and the sixth switching element Q6, and the cathode of its freewheeling diode D5 can be connected to the positive terminal 372p of the second input / output terminal. The cathode of the freewheeling diode D6 of the sixth switching element Q6 can be connected to the connection node between the fifth switching element Q5 and the sixth switching element Q6, and the anode of its freewheeling diode D6 can be connected to the negative terminal 372n of the second input / output terminal. Similarly, the anode of the freewheeling diode D7 of the seventh switching element Q7 can be connected to the connection node between the seventh switching element Q7 and the eighth switching element Q8, and the cathode of its freewheeling diode D7 can be connected to the positive terminal 372p of the second input / output terminal. The cathode of the freewheeling diode D8 of the eighth switching element Q8 can be connected to the connection node between the seventh switching element Q7 and the eighth switching element Q8, and the anode of its freewheeling diode D8 can be connected to the negative terminal 372n of the second input / output terminal.

[0039] When the battery 10 is being charged, the controller 100 can control the switching elements Q1 to Q8 provided in the OBC 30 to apply a DC voltage of an appropriate magnitude that can charge the battery 10. Specifically, when the temperature of the battery 10 is lower than a predetermined reference temperature such that the battery 10 is in a low-temperature state, in order to increase the temperature of the battery 10, the controller 100 can control the switching elements Q1 to Q8 provided in the OBC 30 and apply an AC current having a predetermined reference frequency to the battery 10, thereby rapidly increasing the temperature of the battery 10. To this end, the controller 100 can receive information about the temperature of the battery 10 from a temperature sensor (not shown) of the battery 10 and detect the state of charge (SOC) of the battery 10 to determine whether the temperature increase control of the battery 10 is feasible.

[0040] In various exemplary forms of the present disclosure, the controller 100 may be implemented in the form of including a non-volatile memory (not shown) and a processor (not shown). The non-volatile memory is configured to store data related to algorithms for controlling the operation of various components of the vehicle or data related to software commands for reproducing the algorithms. The processor is configured to operate using the data stored in the non-volatile memory. Here, the non-volatile memory and the processor may be implemented as separate chips. Alternatively, the non-volatile memory and the processor may be implemented as a single integrated chip, and the processor may be implemented in the form of one or more processors.

[0041] In Figure 1 and Figure 2 the reference numeral "39" denotes an output filter for removing noise and the like included in the power supplied to the battery 10.

[0042] The more detailed control operations of the controller 100 and the effects produced by the control operations will be more clearly understood through the following description of the control method for the vehicle's control power system.

[0043] Figure 3 is a flowchart showing the operation of a system for increasing the battery temperature of a vehicle according to one form of the present disclosure.

[0044] See Figure 3 In a system for increasing the battery temperature of a vehicle, after the vehicle starts, the controller 100 may perform operation S11: receiving the state information of the main battery 10 and determining whether temperature increase control is desired. In operation S11, when the controller 100 determines that the state is sufficient for temperature increase control because the temperature of the battery 10 is lower than a predetermined reference temperature and the SOC of the battery 10 is greater than or equal to a predetermined reference value, the controller 100 may start the temperature increase control for the battery 10 (S12).

[0045] At the start of the temperature increase control (S12), the controller 100 may set the counter time T cntSet to zero, and control the bidirectional DC converter 37 to transfer the power from the battery 10 to the capacitor 35, that is, transfer from the second input / output terminals 372p and 372n of the bidirectional DC converter 37 to its first input / output terminals 371p and 371n (S13). In operation S13, the controller 100 can turn on or off the fifth switch element Q5 to the eighth switch element Q8 of the second switch circuit 375, and convert the DC voltage of the battery 10 into an AC voltage to apply the AC voltage to the secondary winding of the transformer 374. Thus, the AC voltage whose magnitude is converted according to the turns ratio of the transformer 374 is induced in the primary winding of the transformer 374. The AC voltage induced in the primary winding is rectified by the freewheeling diodes D1 to D4 of the first switch circuit 373 and applied to the capacitor 35, so that the capacitor 35 is charged.

[0046] When the voltage V of the capacitor 35 link becomes greater than the predetermined reference voltage k*v bat (S14), the controller 100 controls the bidirectional DC converter 37 to transfer the power from the capacitor 35 to the battery 10, that is, transfer from the first input / output terminals 371p and 371n of the bidirectional DC converter 37 to its second input / output terminals 372p and 372n (S15), and the controller 100 adds the temperature rise control period T cont to the counter time T cnt to record the added result (S16). Here, the temperature rise control period T cont refers to the period for performing the temperature rise control task. For example, when the temperature rise control task is performed at a frequency of 100 kHz, the temperature rise control period T cont can become 1 / 100000 second.

[0047] To control the bidirectional DC converter 37 to transfer the power from the first input / output terminals 371p and 371n to the second input / output terminals 372p and 372n, the controller 100 can turn on or off the first switch element Q1 to the fourth switch element Q4 of the first switch circuit 373, and convert the DC voltage of the battery 10 into an AC voltage to apply the AC voltage to the primary winding of the transformer 374. Thus, the AC voltage whose magnitude is converted according to the turns ratio of the transformer 374 is induced in the secondary winding of the transformer 374. The AC voltage induced in the secondary winding is rectified by the freewheeling diodes D5 to D8 of the second switch circuit 375 and applied to the battery 10, so that the battery 10 is charged.

[0048] In Figure 3In this case, "Charge_Mode" refers to the power transfer direction of the bidirectional DC converter 37. A value of 0 for "Charge_Mode" means that the bidirectional DC converter 37 operates to transfer power from the second input / output terminals 372p and 372n to the first input / output terminals 371p and 371n, and a value of 1 for "Charge_Mode" means that the bidirectional DC converter 37 operates to transfer power from the first input / output terminals 371p and 371n to the second input / output terminals 372p and 372n. The bidirectional DC converter 37 is a device whose main purpose is to convert external power and transfer the converted external power to the battery 10. For ease of description, when the power transfer direction is from the first input / output terminals 371p and 371n of the bidirectional DC converter 37 to its second input / output terminals 372p and 372n, this is referred to as forward, and when the power transfer direction is from the second input / output terminals 372p and 372n to the first input / output terminals 371p and 371n, this is referred to as reverse.

[0049] Subsequently, the controller 100 may check the temperature and SOC of the battery 10 to determine whether the temperature increase control of the battery 10 can be terminated (S17). When it is determined that the temperature increase control of the battery 10 cannot be terminated, the controller 100 may set the counter time T cnt to the alternating period T ripple of a predetermined battery current for comparison (S18).

[0050] When determining whether the temperature increase control of the battery 10 can be terminated (S17), when the controller 100 determines that the state is insufficient for temperature increase control because the temperature of the battery 10 is greater than or equal to a predetermined reference temperature or the SOC of the battery 10 is equal to or less than a predetermined reference value, the controller 100 may terminate the temperature increase control of the battery 10. When the temperature of the battery 10 is lower than the predetermined reference temperature and its SOC is greater than or equal to the predetermined reference value, the controller 100 may determine to continuously perform the temperature increase control.

[0051] When comparing the counter time T cnt with the alternating period T ripple of a predetermined battery current (S18), the controller 100 may reset the counter time T cnt to 1 / 2 of the predetermined alternating period T ripple when the counter time T cntSet to zero (S19), and when the bidirectional DC charger 30 is in the state of performing the forward operation (S20), the controller 100 can control the bidirectional DC charger 30 so that the bidirectional DC charger 30 performs the reverse operation. In addition, when the bidirectional DC charger 30 is in the state of performing the reverse operation instead of the forward operation (S20), the controller 100 can control the bidirectional DC charger 30 to perform the forward operation (S15).

[0052] Through the above control of the controller 100, the bidirectional DC charger 30 can repeat the forward operation and the reverse operation during the alternating cycle as Figure 4 shown.

[0053] Figure 4 A waveform diagram is shown, showing the operation of the switching circuit of the system for increasing the battery temperature for a vehicle according to one form of the present disclosure and the flow of alternating current (AC) according to the operation of the switching circuit thereof.

[0054] Referring to Figure 4 , due to the control of the controller 100 as Figure 3 shown, the bidirectional DC charger 30 of the system for increasing the battery temperature for a vehicle can repeat the forward operation and the reverse operation during an alternating cycle. In Figure 4 , in the section indicated by "Q pri ", the controller 100 turns on or off the switching elements S1 to S4 included in the first switching circuit 373 of the bidirectional DC charger 30 to supply the power charged in the capacitor 35 to the battery 10. In the section Q pri , the voltage V link of the capacitor 35 decreases and the current i bat supplied to the battery 10 increases.

[0055] Furthermore, in Figure 4 , in the section indicated by "Q sec ", the controller 100 turns on or off the switching elements S5 to S8 included in the second switching circuit 375 of the bidirectional DC charger 30 to supply the power of the battery 10 to the capacitor 35. In the section Q sec , the voltage V link of the capacitor 35 increases and the current i bat supplied to the battery 10 increases, thereby realizing the state of outputting current from the battery 10.

[0056] As described above, according to one form of the present disclosure, by changing the power transmission direction of the bidirectional DC converter 37 in the OBC 30 at a predetermined cycle to supply the AC current to the battery 10, the temperature of the battery 10 can be increased.

[0057] During the above-described temperature increase control of the battery, the power factor compensation circuit 33 in the OBC 30 may not operate.

[0058] Meanwhile, according to one form of the present disclosure, the frequency of the AC current may be determined by the current frequency-impedance characteristics of the battery 10. Since the internal resistance (internal impedance) of the battery 10 increases very significantly in a low-temperature environment, even when the AC current increases, there may be a situation where the battery 10 cannot output or receive the AC current. Therefore, according to one form of the present disclosure, considering the frequency-impedance characteristics of the battery 10, even when the temperature of the battery 10 is in a low-temperature state, it is desirable to select the frequency of the AC current within a frequency range where the impedance of the battery 10 exhibits a low level. That is, even in the low-temperature state in the region indicated by "A" in the Figure 5 example showing the current frequency-impedance relationship of the battery 10, it is desirable to determine the frequency of the AC current in the region where the impedance |Z| of the battery 10 exhibits a relatively low level (at a frequency of about 1 kHz in the Figure 5 example). Here, as Figure 4 shown, the frequency of the AC current is substantially the same as the change frequency in the power transfer direction of the bidirectional DC converter 30.

[0059] In addition, according to various forms of the present disclosure, the frequency of the AC current supplied to the battery 10 during the temperature increase control has a value less than the switching frequency of the switching elements Q1 to Q8 in the first switching circuit 373 and the second switching circuit 375. Due to the switching of the switching elements Q1 to Q8 in the first switching circuit 373 and the second switching circuit 375, an AC current can be formed. That is, by repeatedly switching the switching elements Q1 to Q8, an AC current with a desired magnitude can be generated. Considering the above description, when the frequency of the AC current is greater than the switching frequency of the switching elements Q1 to Q8, since the rate of change of the AC current is higher than the rate of forming the AC current by the switching of the switching elements Q1 to Q8, it is impossible to generate an AC current with a desired magnitude. Therefore, the frequency of the AC current should have a value less than the switching frequency of the switching elements Q1 to Q8 in the first switching circuit 373 and the second switching circuit 375.

[0060] As described above, the system for increasing the battery temperature for a vehicle can increase the battery temperature in a low-temperature environment by using a charger installed in the vehicle without using an additional device for temperature increase, so that power consumption can be reduced, the system can be simplified, and an increase in the unit cost of the vehicle can be suppressed.

[0061] In addition, a system for increasing the battery temperature of a vehicle selects the frequency of the AC current supplied to the battery from a frequency region in the current frequency-impedance relationship of the battery that has a relatively low impedance even at low temperatures, so that even in the case of extremely low temperatures, the temperature increase control of the battery can be performed.

[0062] According to the system for increasing the battery temperature of a vehicle, the battery temperature can be increased in a low-temperature environment by using a charger installed in the vehicle without using an additional device for temperature increase. Therefore, power consumption can be reduced, the system can be simplified, and an increase in the unit cost of the vehicle can be suppressed.

[0063] In addition, according to the system for increasing the battery temperature of a vehicle, the frequency of the AC current supplied to the battery is selected from a frequency region in the current frequency-impedance relationship of the battery that has a relatively low impedance even at low temperatures, so that even in the case of extremely low temperatures, the temperature increase control of the battery can be performed.

[0064] The effects obtained from the present disclosure are not limited to the above effects, and other effects not mentioned can be clearly understood by those skilled in the art to which the present disclosure pertains from the above description.

[0065] Although an exemplary form of the present disclosure has been described for illustrative purposes, those skilled in the art will understand that various modifications, additions, and substitutions are possible without departing from the scope and spirit of the present disclosure.

[0066] Although specific forms of the present disclosure have been described in detail, it will be apparent to those skilled in the art that various modifications and changes can be made without departing from the technical spirit and scope of the present disclosure, and these modifications and changes fall within the scope of the present disclosure.

Claims

1. A system for increasing the temperature of a battery for a vehicle, the system comprising: An on-vehicle charger, the on-vehicle charger including a capacitor and a bidirectional DC converter, the bidirectional DC converter having a first input / output terminal connected to the capacitor and a second input / output terminal connected to the battery and being configured to perform bidirectional power transfer between the first input / output terminal and the second input / output terminal; And A controller configured to: When the battery needs to be heated, drive the bidirectional DC converter such that the direction of power transfer alternates, and Supply an alternating current having a predetermined frequency to the battery, Wherein the bidirectional DC converter includes: A transformer; A first switch circuit connected between the first input / output terminal and the primary winding of the transformer, and the first switch circuit includes a plurality of switch elements; and A second switch circuit connected between the second input / output terminal and the secondary winding of the transformer, and the second switch circuit includes a plurality of switch elements, Wherein the controller is configured to alternately perform a forward operation and a reverse operation based on the predetermined frequency. In the reverse operation, a plurality of switch elements of the second switch circuit are turned on or off so as to supply power from the battery to the capacitor such that the capacitor is charged. In the forward operation, when the voltage of the capacitor is greater than a predetermined reference voltage, a plurality of switch elements of the first switch circuit are turned on or off so as to supply power from the capacitor to the battery such that the battery is charged.

2. The system according to claim 1, wherein The on-vehicle charger further includes a power factor correction circuit configured to: Convert external AC power into DC power, and In a charging mode, apply the DC power to the capacitor. In the charging mode, the external AC power is converted into the DC power and the DC power is supplied to the battery; And When the battery needs to be heated, the controller does not operate the power factor correction circuit.

3. The system according to claim 1, wherein When the battery needs to be heated, the controller is configured to control the plurality of switch elements of the first switch circuit and the plurality of switch elements of the second switch circuit to alternately switch.

4. The system according to claim 1, wherein, The first switch circuit is a bridge circuit, the bridge circuit including a first switch element and a second switch element connected in series between a positive terminal and a negative terminal of the first input / output terminal, and a third switch element and a fourth switch element connected in series between the positive terminal and the negative terminal of the first input / output terminal, Wherein the bridge circuit further includes: a first connection node between the first switch element and the second switch element, and a second connection node between the third switch element and the fourth switch element, and Wherein the first connection node is connected to a first end of the primary winding of the transformer, and the second connection node is connected to a second end of the primary winding of the transformer.

5. The system according to claim 1, wherein, The second switching circuit is a bridge circuit, and the bridge circuit includes a fifth switching element and a sixth switching element connected in series between the positive terminal and the negative terminal of the second input / output terminal, and a seventh switching element and an eighth switching element connected in series between the positive terminal and the negative terminal of the second input / output terminal, and wherein, in the bridge circuit, a connection node between the fifth switching element and the sixth switching element is connected to a first end of the secondary winding of the transformer, and a connection node between the seventh switching element and the eighth switching element is connected to a second end of the secondary winding of the transformer.

6. The system according to claim 1, wherein, The predetermined frequency is less than the switching frequency of the plurality of switching elements of the first switching circuit or the switching frequency of the plurality of switching elements of the second switching circuit.

7. The system according to claim 1, wherein The predetermined frequency is determined based on a current frequency in a region where the impedance exhibits a relatively low level compared to the current frequency-impedance characteristic of the battery.

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