Battery heating method and battery heating device

Abstract

An aspect of the present invention is a battery heating method for heating a battery in an electric vehicle when the temperature of the battery, which supplies power to an electric powertrain, is lower than a prescribed temperature determined in advance, or when it is estimated that the temperature of the battery will become lower than the prescribed temperature. This battery heating method has, as heating modes for heating the battery, a first mode for heating the battery by using heat generated by the battery itself, and a second mode for heating the battery by using heat generated by the electric powertrain. The first mode and the second mode are switched until the temperature of the battery reaches the prescribed temperature.

Description

Battery warm-up method and battery warm-up device

[0001] The present invention relates to a battery warm-up method and a battery warm-up device.

[0002] JP5849917B discloses a battery temperature control device that heats up an on-board battery by alternately repeating discharge control, which causes a d-axis current to flow through the motor, and charge control, which returns energy stored in the motor windings to the battery.

[0003] Battery performance deteriorates in low-temperature environments. For this reason, in an electric vehicle powered by a battery, it is desirable to maintain battery performance by warming up the battery when the battery temperature drops or when it is expected that the battery temperature will drop.

[0004] When warming up a battery, a heater such as a PTC (Positive Temperature Coefficient) heater is generally used, but adding a heater just to warm up the battery increases costs, etc. For this reason, in recent years, methods have been proposed for warming up a battery without adding a heater, such as by repeatedly discharging and charging the battery to generate heat, or by transporting heat generated by an electric motor to warm up the battery.

[0005] However, in warm-up methods that generate heat by repeatedly charging and discharging the battery, the current that can be applied during the charging and discharging is limited to a small value in order to suppress electrodeposition during charging. In other words, in warm-up methods that generate heat by repeatedly charging and discharging the battery, the amount of heat generated is small, and it takes a long time to warm up the battery.

[0006] On the other hand, in warm-up methods that use heat generated by the electric motor, a considerable amount of heat is dissipated during transportation. Also, when the electric motor is cold, it is necessary to warm up the electric motor itself before warming up the battery. In other words, warm-up methods that use heat generated by the electric motor can be energy inefficient.

[0007] An object of the present invention is to provide a battery warm-up method and a battery warm-up device that can warm up a battery in an electric vehicle with high energy efficiency in a short time.

[0008] One aspect of the present invention is a battery warm-up method for warming up a battery in an electric vehicle when the temperature of a battery that supplies power to an electric powertrain is lower than a predetermined temperature or when the battery temperature is expected to fall below the predetermined temperature. The battery warm-up method has two warm-up modes for warming up the battery: a first mode in which the battery is warmed up by heat generated by the battery itself, and a second mode in which the battery is warmed up by heat generated by the electric powertrain. The method switches between the first mode and the second mode until the battery temperature reaches the predetermined temperature.

[0009] FIG. 1 is a block diagram showing a schematic configuration of an electric vehicle. FIG. 2 is a graph showing a schematic change in d-axis voltage, d-axis current, and battery current in a first mode. FIG. 3 is a graph showing a schematic change in d-axis voltage, d-axis current, and battery current in a second mode. FIG. 4 is a block diagram showing a configuration of a warm-up control unit. FIG. 5 is a graph showing a schematic change in heat quantity and efficiency in each mode after warm-up starts. FIG. 6 is a graph showing a change in warm-up mode in a warm-up speed priority setting. FIG. 7 is a graph showing a change in warm-up mode in an efficiency priority setting. FIG. 8 is a flowchart showing a change in warm-up mode. FIG. 9 is a flowchart showing a flow path control of a heat exchange medium. FIG. 10 is a flowchart showing a flow path control according to a modified example. FIG. 11 is a flowchart showing a flow path control according to a modified example.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] Fig. 1 is a block diagram showing a schematic configuration of an electric vehicle 100. As shown in Fig. 1, the electric vehicle 100 is a vehicle such as an electric vehicle or a hybrid vehicle that generates driving force using electric power supplied by a battery 10, and includes, in addition to the battery 10, an electric powertrain 11, a heat exchange system 12, a temperature adjustment control unit 13, and a controller 14.

[0012] The battery 10 is a secondary battery such as a lithium-ion battery, and is capable of discharging and charging. When the electric vehicle 100 is traveling, the battery 10 supplies DC power to the electric powertrain 11. When the electric vehicle 100 decelerates, the battery 10 is charged by inputting electric power generated in the electric powertrain 11 through so-called regenerative control. When the electric powertrain 11 includes a power generation system, the battery 10 is charged by electric power generated by the power generation system.

[0013] In this embodiment, in order to maintain performance, the temperature of the battery 10 (hereinafter referred to as the battery temperature θ) is kept constant at least during use. １ ) is within a predetermined temperature range (for example, θ ｍｉｎ ≦θ １ ≦θ ｍａｘ The battery 10 is warmed up or cooled down so that the battery temperature θ １ Lower limit θ ｍｉｎ and upper limit θ ｍａｘ is determined in advance by experiment, simulation, or the like.

[0014] For example, if the ambient temperature is lower limit θ ｍｉｎ When the electric vehicle 100 is started from a stopped state for a long time in a cold region where the temperature is lower than the ambient temperature, the battery temperature θ １ is the lower limit θ ｍｉｎ In this manner, the battery 10 is warmed up. In addition, for example, when the electric vehicle 100 continues to be stopped in a cold region while being able to start, the battery temperature θ １ is the lower limit θ ｍｉｎ When the value is lower than the lower limit θ ｍｉｎThat is, in the electric vehicle 100, the battery 10 is warmed up when the battery temperature θ １ is a predetermined lower limit θ ｍｉｎ or when the battery temperature θ １ is the lower limit θ ｍｉｎ The battery 10 is warmed up when the battery temperature θ is expected to be lower than the target value. １ The lower limit θ ｍｉｎ or higher. That is, the lower limit θ ｍｉｎ A temperature equal to or higher than the predetermined temperature (target temperature) targeted for warm-up control. ｍｉｎ is the target temperature.

[0015] In addition, when the battery 10 is rapidly charged, the battery temperature θ １ is the upper limit θ ｍａｘ or when the battery temperature θ １ is the upper limit θ ｍａｘ When the temperature is expected to be higher than 100°C, the battery 10 is cooled.

[0016] In addition, the current input and output to and from the battery 10 (hereinafter referred to as battery current I ｂａｔ The current and voltage of the battery 10 are measured by a current sensor 21 and a voltage sensor 22, respectively, and can be acquired at any timing. The SOC (State of Charge) representing the charging rate of the battery 10 can be calculated at any timing based on the voltage (open circuit voltage, etc.) of the battery 10. In addition, the battery temperature θ １ is measured by the temperature sensor 23 and can be acquired at any timing.

[0017] The electric powertrain 11 (ePT) is a collection of devices for generating driving force for the electric vehicle 100, and includes at least one rotating electric machine 25 and an inverter 26 that drives the rotating electric machine 25. The electric powertrain 11 may include a power generation system (not shown) that generates electric power to charge the battery 10. The power generation system is configured using, for example, an internal combustion engine and a generator.

[0018] The rotating electric machine 25 is an electric motor or a generator. More specifically, the rotating electric machine 25 is an electric motor that generates driving force for the electric vehicle 100, or a generator included in a power generation system. The rotating electric machine 25 includes windings 27 in its stator, rotor, or both the stator and rotor. In this embodiment, the rotating electric machine 25 is a three-phase AC synchronous motor that generates driving force for the electric vehicle 100, and at least the stator has windings 27 for generating a rotating magnetic field. In this embodiment, the windings 27 of the rotating electric machine 25 are also used in control for warming up the battery 10 (hereinafter referred to as warm-up control of the battery 10).

[0019] The inverter 26 is connected to the battery 10. The inverter 26 drives the rotating electric machine 25 using DC power output from the battery 10. In this embodiment, the inverter 26 converts DC power from the battery 10 into three-phase AC power by turning on and off a plurality of switching elements contained therein, and supplies the three-phase AC power to the rotating electric machine 25, thereby causing the rotating electric machine 25 to generate torque. This torque generates driving force for the electric vehicle 100. The inverter 26 also charges the battery 10 by inputting the power generated by the rotating electric machine 25 to the battery 10. In this embodiment, the inverter 26 converts AC power generated by the rotating electric machine 25 into DC power by turning on and off the switching elements, and inputs the DC power to the battery 10. In addition, in this embodiment, the inverter 26 is also used for warm-up control of the battery 10.

[0020] In addition, the electric vehicle 100 monitors the temperature of the electric powertrain 11 (hereinafter referred to as ePT temperature θ ２ A temperature sensor 28 measures the carrier frequency or switching frequency (hereinafter referred to as the carrier frequency f ２ Therefore, the ePT temperature θ ２ and carrier frequency f ２ can be acquired at any time.

[0021] The heat exchange system 12 exchanges heat with the battery 10 and the electric powertrain 11, and warms or cools the battery 10 and the electric powertrain 11, respectively or simultaneously. The heat exchange system 12 is, in principle, a cooling system that cools the electric powertrain 11 and the battery 10, whose temperatures rise when the electric vehicle 100 is running, etc. In the warm-up control of the battery 10 in this embodiment, the heat exchange system 12 functions as a heat transport system that warms the battery 10 by transporting (moving) heat generated in the electric powertrain 11 to the battery 10. The medium (hereinafter referred to as the heat exchange medium) used by the heat exchange system 12 to exchange heat with the battery 10 and the electric powertrain 11 is, for example, water or another liquid, or a gas. The heat exchange system 12 specifically includes a first heat exchange unit 31, a second heat exchange unit 32, and a heat exchange medium cooling unit 33.

[0022] The first heat exchanger 31 is a part of the heat exchange system 12 that is thermally connected to the battery 10 and exchanges heat with the battery 10 .

[0023] The first heat exchange unit 31 is connected to the heat exchange medium cooling unit 33 by a first flow path 34 that circulates the heat exchange medium between the first heat exchange unit 31 and the heat exchange medium cooling unit 33. A valve (not shown) is provided in the first flow path 34, and by opening this valve, the first heat exchange unit 31 is thermally connected to the heat exchange medium cooling unit 33, and by closing this valve, the connection between the first heat exchange unit 31 and the heat exchange medium cooling unit 33 is released.

[0024] The first heat exchanger 31 is connected to the second heat exchanger 32 by a second flow path 35 that circulates a heat exchange medium between the first heat exchanger 31 and the second heat exchanger 32. A valve (not shown) is provided in the second flow path 35, and by opening this valve, the first heat exchanger 31 is thermally connected to the second heat exchanger 32, and by closing this valve, the connection between the first heat exchanger 31 and the second heat exchanger 32 is released.

[0025] The second heat exchange unit 32 is a part of the heat exchange system 12 that is thermally connected to the electric powertrain 11 and exchanges heat with the electric powertrain 11 .

[0026] As described above, the second heat exchange unit 32 is connected to the first heat exchange unit 31 by the second flow path 35, and is also connected to the heat exchange medium cooling unit 33 by a third flow path 36 that circulates the heat exchange medium between the second heat exchange unit 32 and the heat exchange medium cooling unit 33. A valve (not shown) is provided in the third flow path 36, and by opening this valve, the second heat exchange unit 32 is thermally connected to the heat exchange medium cooling unit 33, and by closing this valve, the connection between the second heat exchange unit 32 and the heat exchange medium cooling unit 33 is released.

[0027] The heat exchange medium cooling unit 33 is a part of the heat exchange system 12 that cools the heat exchange medium that carries heat generated in the battery 10 and the electric powertrain 11 using outside air (wind generated when the electric vehicle 100 is running) or the like. The heat exchange medium cooling unit 33 is, for example, a radiator for the electric vehicle 100. The heat exchange medium cooling unit 33 is connected to the first heat exchange unit 31, the second heat exchange unit 32, or both, as necessary, and cools the heat exchange medium circulating therethrough to cool the battery 10 and the electric powertrain 11. Therefore, when warm-up control of the battery 10 is performed, the heat exchange medium cooling unit 33 is disconnected from at least the first heat exchange unit 31. In this embodiment, for simplicity, it is assumed that when warm-up control of the battery 10 is performed, the connection between the heat exchange medium cooling unit 33 and the first heat exchange unit 31 and the connection between the heat exchange medium cooling unit 33 and the second heat exchange unit 32 are both disconnected.

[0028] In addition, the heat exchange system 12 includes one or more pumps, compressors, or blowers (hereinafter referred to as pumps) (not shown) for circulating the heat exchange medium between the various parts. Note that, with respect to the various parts of the heat exchange system 12, "connecting" them means opening the valves in the flow paths connecting them and operating the pumps to circulate the heat exchange medium, thereby transporting heat between the various parts.

[0029] The temperature adjustment control unit 13 opens and closes the valves in the heat exchange system 12 in accordance with instructions from the controller 14. The temperature adjustment control unit 13 also operates or stops the pumps in the heat exchange system 12 in accordance with instructions from the controller 14. In this way, the temperature adjustment control unit 13 changes the state of the heat exchange system 12, and warms up or cools down the battery 10 and the electric powertrain 11, either individually or simultaneously.

[0030] The controller 14 is one or more computers that comprehensively control the operation of the electric vehicle 100, the operation of each component constituting the electric vehicle 100, and the operation of the electric vehicle 100 as a whole. Specifically, the controller 14 is programmed to control the electric powertrain 11 and to control the running of the electric vehicle 100. The controller 14 is also programmed to control the electric powertrain 11 to perform warm-up control of the battery 10. Therefore, the controller 14 constitutes a battery warm-up control device in the electric vehicle 100. In the warm-up control of the battery 10, the controller 14 may also control the heat exchange system 12 via the temperature adjustment control unit 13.

[0031] Specifically, the controller 14 functions as, for example, a state detection unit 41, a rotating electrical machine control unit 42, a warm-up control unit 43, and the like.

[0032] The state detection unit 41 detects the operating state of the electric vehicle 100 or the operating state of each component of the electric vehicle 100. For example, the state detection unit 41 detects the battery temperature θ by acquiring the output signal of the temperature sensor 23. １ Furthermore, the state detection unit 41 acquires the output signal of the temperature sensor 28 and detects the ePT temperature θ ２ Similarly, the state detector 41 detects the carrier frequency f ２, current and voltage input and output to and from the battery 10, accelerator opening (accelerator operation amount) of the electric vehicle 100, vehicle speed, and rotation speed of the rotating electric machine 25, etc. The state detection unit 41 acquires the above parameters using various sensors, etc., and may also use the acquired parameters to calculate other parameters used in the rotating electric machine control unit 42 and the warm-up control unit 43 for detection. In this embodiment, the state detection unit 41 estimates the SOC of the battery 10 based on the output voltage of the battery 10, etc. The parameters detected by the state detection unit 41 are used in various controls performed by the rotating electric machine control unit 42 and the warm-up control unit 43.

[0033] The rotating electric machine control unit 42 controls the driving of the rotating electric machine 25. For example, the rotating electric machine control unit 42 calculates target values ​​(command values) such as the rotation speed that the rotating electric machine 25 should reach or maintain, or the torque that the rotating electric machine 25 should generate, in response to a request for the electric vehicle 100. These target values ​​are calculated based on, for example, the rotation speed of the rotating electric machine 25 and the accelerator opening degree of the electric vehicle 100. Furthermore, the rotating electric machine control unit 42 adjusts the voltage, current, and the like supplied to the rotating electric machine 25 by operating the inverter 26 based on these calculated target values. As a result, the rotating electric machine 25 maintains a rotation speed corresponding to the target value set in response to the request for the electric vehicle 100, or generates a torque corresponding to the target value set in response to the request for the electric vehicle 100.

[0034] Furthermore, in the present embodiment, when performing warm-up control of the battery 10, the rotating electric machine control unit 42 may control the inverter 26 and the rotating electric machine 25 in accordance with instructions from the warm-up control unit 43. For example, the rotating electric machine control unit 42 supplies electric power to the inverter 26 and the rotating electric machine 25, or inputs electric power from the rotating electric machine 25 to the battery 10 via the inverter 26, in response to a request from the warm-up control unit 43. As a result, the rotating electric machine control unit 42 causes heat to be generated in the rotating electric machine 25 and the inverter 26, thereby warming up the electric powertrain 11. In this way, the heat generated in the electric powertrain 11, such as the rotating electric machine 25 and the inverter 26 (hereinafter referred to as heat generated in the electric powertrain 11), is transported to the battery 10 and used to warm up the battery 10.

[0035] The warm-up control unit 43 performs warm-up control of the battery 10. The warm-up control of the battery 10 performed by the warm-up control unit 43 has two modes (warm-up modes) that differ in the specific method for warming up the battery 10, as follows.

[0036] The first warm-up mode (hereinafter simply referred to as the first mode) is a warm-up mode in which the battery 10 is warmed up by heat generated by the battery 10 itself. That is, in the first mode, the warm-up control unit 43 warms up the battery 10 by causing the battery 10 itself to generate heat. At this time, of the electric power stored in the battery 10, only the amount that is converted into thermal energy in the battery 10 is substantially consumed.

[0037] In this embodiment, in the first mode, the warm-up control unit 43 stores energy in elements included in the electric power train 11 by discharging the battery 10, and then charges the battery with the energy stored in the elements. The warm-up control unit 43 repeats this discharging and charging to control the battery current I ｂａｔ and the internal resistance R of the battery 10 ｂａｔ This causes the battery 10 itself to generate heat.

[0038] In this embodiment, the element that stores energy in the electric powertrain 11 is the winding 27 of the rotating electric machine 25. That is, the warm-up control unit 43 causes the battery 10 to energize the winding 27, thereby storing energy corresponding to the inductance of the winding 27. Thereafter, the warm-up control unit 43 stops the supply of power to the winding 27, and charges the battery 10 with the energy stored in the winding 27.

[0039] If the electric powertrain 11 includes, in addition to the winding 27, an inductor, a capacitor, or the like that can be used for the above-mentioned purpose, the warm-up control unit 43 can, in the first mode, store the energy discharged from the battery 10 in those elements instead of the winding 27. Furthermore, if the electric powertrain 11 has multiple elements that can be used for the above-mentioned purpose, the warm-up control unit 43 can store the energy discharged from the battery 10 in those multiple elements.

[0040] In addition, the current that the warm-up control unit 43 supplies to the rotating electrical machine 25 in the first mode is a so-called d-axis current I ｄ Of the currents flowing through the rotating electrical machine 25, the d-axis current I ｄ is the current component for generating a magnetic field, and the q-axis current I ｑ (not shown) is a current component for generating torque. Therefore, the warm-up control unit 43 applies a voltage to the d-axis of the rotating electrical machine 25, and selectively supplies the d-axis current I ｄ By supplying or increasing the current, energy can be stored in the windings 27 without changing the rotation state of the rotating electrical machine 25 .

[0041] FIG. 2 shows the d-axis voltage V ｄ , (B) d-axis current I ｄ , and (C) battery current I ｂａｔ 4 is a graph showing a typical change in the d-axis voltage V ｄ is the d-axis component of the voltage input / output to / from the rotating electric machine 25. Note that Fig. 2 shows an example in which the rotating electric machine 25 is at a stop.

[0042] In the first mode, the d-axis voltage V ｄ That is, as shown in FIG. 2A, the d-axis voltage V ｄ In this way, the storage and release of energy in the winding 27 is repeated in accordance with the cycle in which the battery 10 is repeatedly discharged and charged, and as shown in FIG. 2B, the d-axis current I ｄAs a result, the battery 10 repeatedly discharges and charges, as shown in FIG. 2C. Here, the positive battery current I ｂａｔ represents the discharge of the battery 10, and the negative battery current I ｂａｔ represents the charging of the battery 10.

[0043] In the second mode, the d-axis current I ｄ When it is necessary to distinguish between the above, the d-axis current I flowing through the rotating electric machine 25 in the first mode is ｄ is the d-axis current I ｄ１ That's what they say.

[0044] In the first mode, the frequency of discharge and charge (hereinafter referred to as the discharge and charge frequency f １ ) is relatively large, and its period (discharge / charge period 1 / f １ ) is short. That is, compared to when the rotating electrical machine 25 is driven to generate torque, the d-axis current I ｄ１ is a so-called high frequency current. １ is, for example, the d-axis current I for driving the rotating electric machine 25 to generate torque. ｄ The frequency band is as high as that of a high-frequency noise current (so-called ripple current) superimposed on the battery 10. Therefore, the warm-up of the battery 10 in the first mode is sometimes called ripple warm-up.

[0045] The second warm-up mode (hereinafter simply referred to as the second mode) is a warm-up mode in which the battery 10 is warmed up by heat generated in the electric powertrain 11. That is, in the second mode, the warm-up control unit 43 intentionally causes the electric powertrain 11 to generate heat and transports the heat thus generated to the battery 10, thereby warming up the battery 10. The warm-up control unit 43 causes the electric powertrain 11 to generate heat by conduction losses in the rotating electric machine 25 and the inverter 26, switching losses in the inverter 26, and the like. Therefore, the electric power supplied from the battery 10 to the electric powertrain 11 is converted into thermal energy and consumed in the electric powertrain 11.

[0046] In the second mode, the warm-up control unit 43 can generate heat in the electric powertrain 11 by, for example, causing the rotating electric machine 25 and the inverter 26 included in the electric powertrain 11 to generate heat. For example, the warm-up control unit 43 can cause the rotating electric machine 25 to generate a d-axis current I ｄ or the d-axis current I ｄ By increasing the carrier frequency f used in the inverter 26, the rotating electrical machine 25 generates heat, thereby generating all or part of the required heat. ２ For example, by increasing the frequency of the inverter 26 to a frequency higher than a predetermined frequency that is set in advance to drive the rotating electric machine 25, the inverter 26 generates heat, thereby generating all or part of the heat that should be generated in the electric powertrain 11.

[0047] In this embodiment, in the second mode, the warm-up control unit 43 supplies the d-axis current I ｄ and the carrier frequency f of the inverter 26 ２ By increasing the value of the temperature, the rotating electric machine 25 and the inverter 26 generate heat, thereby generating heat in the electric powertrain 11. However, the warm-up control unit 43 can generate some or all of the heat that should be generated in the electric powertrain 11 by causing components other than the rotating electric machine 25 and the inverter 26 to generate heat.

[0048] FIG. 3 shows the d-axis voltage V ｄ , d-axis current I ｄ , and the battery current I ｂａｔ 3 is a graph showing a schematic transition of the rotational speed of the rotating electric machine 25. Note that Fig. 3 shows an example in a state where the rotating electric machine 25 is stopped from rotating.

[0049] As shown in FIG. 3A, in the second mode, the rotating electric machine 25 receives a substantially constant d-axis voltage V ｄ Therefore, as shown in FIG. 3B, the d-axis current I ｄ Also, as shown in FIG. 3C, the battery current I ｂａｔTherefore, in the second mode, the battery 10 continues to consume the electric power that is converted into heat by the rotating electric machine 25 and the like.

[0050] The d-axis current I ｄ１ When it is necessary to distinguish between the d-axis current I ｄ , the d-axis current I ｄ２ The warm-up of the battery 10 in the second mode is substantially the same as the d-axis current I ｄ This is sometimes called d-axis warm-up because it converts the heat energy into

[0051] The warm-up control unit 43 (see FIG. 1) warms up the battery 10 faster or more energy-efficiently by appropriately switching the warm-up mode in the warm-up control of the battery 10 than when one of the warm-up modes is continuously executed. For example, when the battery temperature θ １ is the lower limit θ ｍｉｎ When warm-up control of the battery 10 is performed from a state where the battery temperature θ １ is the lower limit θ ｍｉｎ In this embodiment, the warm-up control unit 43 starts warming up the battery 10 in the first mode, and then switches the warm-up mode to the second mode, and the battery temperature θ １ The lower limit θ ｍｉｎ Allow the temperature to reach above this level.

[0052] In addition, the warm-up control unit 43 can control the heat exchange system 12 via the temperature adjustment control unit 13 to warm up the battery 10. When warming up the battery 10 at least in the second mode, the warm-up control unit 43 opens the valve of the second flow path 35, connects the first heat exchange unit 31 and the second heat exchange unit 32, and circulates the heat exchange medium between the first heat exchange unit 31 and the second heat exchange unit 32. This allows the warm-up control unit 43 to transport heat generated in the electric powertrain 11 to the battery 10. Furthermore, when performing warm-up control of the battery 10, the warm-up control unit 43 closes the valves of the first flow path 34 and the third flow path 36 and disconnects the first heat exchange unit 31 and the second heat exchange unit 32 from the heat exchange medium cooling unit 33. This is to prevent heat generated in the battery 10 and heat generated in the electric powertrain 11 from being lost.

[0053] Fig. 4 is a block diagram showing the configuration of the warm-up control unit 43. As shown in Fig. 4, the warm-up control unit 43 includes (1) a first mode calculation unit 51, (2) a second mode calculation unit 52, and (3) a mode switching determination unit 53.

[0054] (1) First Mode Calculation Unit 51 The first mode calculation unit 51 calculates a command value and the like when warming up the battery 10 in the first mode. Specifically, the first mode calculation unit 51 calculates the SOC and battery temperature θ of the battery 10. １ Based on this, the first current command value I ｄ１ ＊ , discharge / charge frequency command value f １ ＊ , heat generation amount Q １ , and the first mode efficiency E １ The first current command value I ｄ１ ＊ is the d-axis current I of the first mode ｄ１ The charge / discharge frequency command value f １ ＊ is the charge / discharge frequency in the first mode f １ The command value for the heat generation amount Q １ is an estimated value of the amount of heat generated by the battery 10 itself when warming up the battery 10 in the first mode that contributes to the temperature rise of the battery 10 without being dissipated, etc. １is the energy efficiency when warming up the battery 10 in the first mode.

[0055] Specifically, the first mode calculation unit 51 includes a first current calculation unit 61 , an internal resistance calculation unit 62 , and a heat generation amount calculation unit 63 .

[0056] The first current calculation unit 61 calculates the SOC of the battery 10 and the battery temperature θ １ Based on this, the first current command value I ｄ１ ＊ and the charge / discharge frequency command value f １ ＊ The first current calculation unit 61 calculates, for example, the SOC and the battery temperature θ １ and the first current command value I ｄ１ ＊ and the charge / discharge frequency command value f １ ＊ The detected SOC and battery temperature θ are calculated by referring to a multidimensional map (hereinafter referred to as a first map) that associates １ The first current command value I ｄ１ ＊ and the charge / discharge frequency command value f １ ＊ The first map (not shown) is determined by adaptation based on, for example, experiments or simulations. The first map is stored in advance in the first current calculation unit 61 or another storage device (not shown).

[0057] Specifically, the first map includes a first mode d-axis current I within a range that does not cause deposition (so-called electrodeposition) of lithium ions or the like due to discharge and charge of the battery 10. ｄ１ The first current command value I ｄ１ ＊ and the charge / discharge frequency command value f １ ＊ The combination is set.

[0058] As a general trend, the battery temperature θ １ The higher the value, the greater the d-axis current I ｄ１ On the other hand, the higher the SOC, the larger the d-axis current I ｄ１ Therefore, the first map is １The higher the first current command value I ｄ１ ＊ On the other hand, the first map is set to increase the battery temperature θ １ The lower the first current command value I ｄ１ ＊ Make it smaller.

[0059] The first current command value I ｄ１ ＊ and the charge / discharge frequency command value f １ ＊ is determined, and the corresponding d-axis current I ｄ１ Discharge and charge frequency f １ By passing the current through the rotating electrical machine 25 at this rate, the internal resistance R of the battery 10 is increased while suppressing electrodeposition. ｂａｔ The amount of heat generated by Q １ is maximized.

[0060] The internal resistance calculation unit 62 calculates the SOC of the battery 10 and the battery temperature θ １ Based on this, the internal resistance R of the battery 10 ｂａｔ The internal resistance calculation unit 62 calculates, for example, the SOC and the battery temperature θ １ and the internal resistance R of the battery 10. ｂａｔ The detected SOC and battery temperature θ are calculated by referring to a multidimensional map (hereinafter referred to as a second map) that associates １ The internal resistance R ｂａｔ The second map (not shown) is determined by adaptation based on, for example, experiments or simulations. The second map is stored in advance in the internal resistance calculation unit 62 or another storage device (not shown).

[0061] As a general trend, the battery temperature θ １ The higher the internal resistance R ｂａｔ The lower the SOC, the smaller the internal resistance R ｂａｔ The battery temperature θ １ This tendency becomes more pronounced as the battery temperature θ １ The lower the SOC, the larger the internal resistance R ｂａｔ Output.

[0062] The heat generation amount calculation unit 63 calculates the first current command value I ｄ１ ＊ and the internal resistance R calculated by the internal resistance calculation unit 62. ｂａｔ Based on this, the heat generation amount Q １ and first mode efficiency E １ The heat generation amount calculation unit 63 calculates, for example, the first current command value I ｄ１ ＊ and internal resistance R ｂａｔ and the heat generation amount Q １ and first mode efficiency E １ The first current command value I is calculated by referring to a multidimensional map (hereinafter referred to as a third map) that associates the first current command value I ｄ１ ＊ and internal resistance R ｂａｔ The heat generation amount Q corresponding to １ and first mode efficiency E １ The third map (not shown) is determined adaptively based on, for example, experiments or simulations. The third map is stored in advance in the heat generation amount calculation unit 63 or another storage device (not shown).

[0063] As a general trend, the first current command value I ｄ１ ＊ The larger the heat generation amount Q １ becomes larger, and the internal resistance R ｂａｔ The larger the heat generation amount Q １ Therefore, the third map is ｄ１ ＊ is large and the internal resistance R ｂａｔ The larger the value, the larger the heat generation amount Q １ The first mode efficiency E １ is the first current command value I ｄ１ ＊ and internal resistance R ｂａｔ It is generally constant regardless of the

[0064] (2) Second Mode Calculation Unit 52 The second mode calculation unit 52 calculates command values ​​and the like when warming up the battery 10 in the second mode. Specifically, the second mode calculation unit 52 calculates the SOC and ePT temperature θ of the battery 10. ２Based on this, the second current command value I ｄ２ ＊ , carrier frequency command value f ２ ＊ , transported heat quantity Q ２ , and the second mode efficiency E ２ The second current command value I ｄ２ ＊ is the d-axis current I of the second mode ｄ２ The carrier frequency command value f ２ ＊ is the carrier frequency f of the inverter 26 ２ The command value for the transported heat quantity Q ２ is an estimate of the amount of heat that can be transported from the electric powertrain 11 to the battery 10 in the second mode, i.e., the amount of heat (received heat amount) that can be received by the battery 10 out of the heat generated in the electric powertrain 11. Therefore, the transported heat amount Q ２ is the heat generated in the electric power train 11 that contributes to the temperature rise of the battery 10. ２ is the energy efficiency when warming up the battery 10 in the second mode.

[0065] Specifically, the second mode calculation unit 52 includes a second current calculation unit 64 and a transported heat amount calculation unit 65 .

[0066] The second current calculation unit 64 calculates the ePT temperature θ ２ Based on this, the second current command value I ｄ２ ＊ and carrier frequency command value f ２ ＊ In this embodiment, the second current command value I ｄ２ ＊ is maximized as far as the heat resistance and other durability of the rotating electrical machine 25 and the inverter 26 (particularly the switching elements) allow. ２ ＊ is maximized as far as the heat resistance and other durability of the inverter 26 allow, for example.

[0067] That is, the second current calculation unit 64, in principle, calculates the maximum second current command value I ｄ２＊ and carrier frequency command value f ２ ＊ Then, for example, the ePT temperature θ ２ is high and there is a risk that the rotating electrical machine 25 and the inverter 26 will exceed their heat resistance limits, the second current calculation unit 64 calculates the ePT temperature θ ２ In response to this, the second current command value I ｄ２ ＊ and carrier frequency command value f ２ ＊ Therefore, for example, when the electric vehicle 100 is in a low-temperature environment and the electric power train 11 is cold, the second current calculation unit 64 limits the second current command value I ｄ２ ＊ and carrier frequency command value f ２ ＊ As a result, in the second mode, the heat generated by the electric powertrain 11 is maximized.

[0068] The transported heat amount calculation unit 65 calculates the battery temperature θ １ and ePT temperature θ ２ Based on this, the transported heat quantity Q ２ and second mode efficiency E ２ The transported heat amount calculation unit 65 calculates, for example, the battery temperature θ １ and ePT temperature θ ２ and the transported heat quantity Q ２ and second mode efficiency E ２ By referring to a multidimensional map (hereinafter referred to as a fourth map) that associates １ and ePT temperature θ ２ The amount of heat transported Q corresponding to ２ and second mode efficiency E ２ The fourth map (not shown) is determined adaptively based on, for example, experiments or simulations. The fourth map is stored in advance in the transport heat amount calculation unit 65 or another storage device (not shown).

[0069] As a general trend, the ePT temperature θ ２ The higher the value, the greater the heat transport quantity Q ２ Also, the battery temperature θ １ The higher the value, the greater the heat transport quantity Q２ Therefore, the fourth map shows that the ePT temperature θ ２ is high and the battery temperature θ １ The higher the value, the larger the transported heat quantity Q ２ Also, the battery temperature θ １ and ePT temperature θ ２ The larger the difference Δθ (not shown), the higher the second mode efficiency E ２ Therefore, the fourth map is １ and ePT temperature θ ２ The higher the difference Δθ, the higher the second mode efficiency E ２ In reality, there is a delay in the heat transport from the electric power train 11 to the battery 10 (thermal time constant τ Ｑ The fourth map is set taking into consideration such a delay as well as the amount of heat dissipated during heat transport.

[0070] (3) Mode Switching Determination Unit 53 The mode switching determination unit 53 determines whether or not switching to the warm-up mode is necessary and the timing thereof. Then, depending on the result of the determination, the mode switching determination unit 53 outputs, for example, a signal indicating the setting of the warm-up mode (hereinafter referred to as the warm-up mode setting S ｍｏｄｅ ), frequency command value f ＊ , and the current command value I ｄ ＊ Output.

[0071] Warm-up mode setting S ｍｏｄｅ indicates the selection of the first mode or the second mode, that is, whether or not switching to the warm-up mode is necessary and the timing.

[0072] The frequency command value f output by the mode switching determination unit 53 ＊ is the charge / discharge frequency command value f １ ＊ or carrier frequency command value f ２ ＊ Specifically, when the selected warm-up mode is the first mode, the frequency command value f ＊ is the frequency command value f ＊ is the charge / discharge frequency command value f １ ＊ When the selected warm-up mode is the second mode, the frequency command value f ＊is the carrier frequency command value f ２ ＊ is.

[0073] The current command value I output by the mode switching determination unit 53 ｄ ＊ is the first current command value I ｄ１ ＊ or the second current command value I ｄ２ ＊ Specifically, when the selected warm-up mode is the first mode, the current command value I ｄ ＊ is the first current command value I ｄ１ ＊ When the selected warm-up mode is the second mode, the current command value I ｄ ＊ is the second current command value I ｄ２ ＊ is.

[0074] The mode switching determination unit 53 determines whether the warm-up mode setting S ｍｏｄｅ , frequency command value f ＊ , and the current command value I ｄ ＊ to the rotating electrical machine control unit 42. As a result, the rotating electrical machine control unit 42 drives the rotating electrical machine 25 and the inverter 26 in accordance with the selected warm-up mode. ｍｏｄｅ is input to the temperature adjustment control unit 13. As a result, the temperature adjustment control unit 13 controls the pump of the heat exchange system 12 and the valves in the flow paths 34, 35, and 36 in accordance with the selected warm-up mode, thereby changing the circulation of the heat exchange medium in accordance with the selected warm-up mode.

[0075] The mode switching determination unit 53 determines the heat generation amount Q １ and transported heat quantity Q ２ In this case, the warm-up mode can be switched based on the heat generation amount Q １ and transported heat quantity Q ２ are compared, and the warm-up mode with the larger heat amount is selected. １ is the transported heat quantity Q ２ When the heat quantity Q becomes larger than the first mode, the first mode is selected. ２ is the heat generation amount Q１ When the second mode is selected, the second mode is selected.

[0076] The mode switching determination unit 53 determines the first mode efficiency E １ and second mode efficiency E ２ In this case, the first mode efficiency E １ and the second mode efficiency E ２ are compared, and the warm-up mode with the greater efficiency is selected. That is, the first mode efficiency E １ is the second mode efficiency E ２ When the efficiency of the first mode is greater than the efficiency of the second mode, E ２ is the first mode efficiency E １ When the second mode is selected, the second mode is selected.

[0077] The mode switching determination unit 53 can change the method of determining whether to switch the warm-up mode depending on the setting, for example. In this embodiment, the setting of the mode switching determination unit 53 includes, for example, a warm-up speed priority setting and an efficiency priority setting. The warm-up speed priority setting is a setting that prioritizes the heat generation amount Q １ and transported heat quantity Q ２ The efficiency priority setting is a setting that determines whether to switch to the warm-up mode based on the first mode efficiency E １ and second mode efficiency E ２ This is the setting for determining whether to switch the warm-up mode based on the above.

[0078] In this embodiment, the mode switching determination unit 53 selects the first mode when starting to warm up the battery 10, and then switches the selected warm-up mode to the second mode according to the above-mentioned determination conditions.

[0079] The operation of the warm-up control of the battery 10 in the electric vehicle 100 configured as described above will now be described.

[0080] 5A and 5B are graphs showing the changes in the heat quantity and efficiency in each mode after the start of warm-up. １ and the heat generation amount Q １ and the total heat quantity ΣH １is the total amount of heat generated in the first mode, and the heat generation amount Q １ As mentioned above, this total heat amount ΣH １ , which is the heat that contributes to the temperature rise of the battery 10. １ FIG. 5C shows the total heat quantity ΣH in the second mode. ２ and the transported heat quantity Q ２ Total heat quantity ΣH ２ is the total amount of heat generated in the second mode, and the transported heat amount Q ２ As mentioned above, this total heat amount ΣH ２ , which is the heat that contributes to the temperature rise of the battery 10. ２ Shows.

[0081] As shown in FIG. 5A, in the first mode, the total heat amount ΣH １ is relatively small, but the total heat amount ΣH １ Heat generation amount Q １ is relatively large and generally constant. Therefore, as shown in FIG. 5B, the first mode efficiency E １ Therefore, the first mode can quickly and efficiently warm up the battery 10, but the total heat amount ΣH １ and the corresponding heat generation amount Q １ Since the temperature is small, it takes time for the battery 10 to warm up.

[0082] On the other hand, as shown in FIG. 5C, in the second mode, the total heat amount ΣH ２ Therefore, in the second mode, the total heat quantity ΣH ２ and the corresponding transported heat quantity Q ２ However, since the amount of transported heat Q ２ This is because when the electric powertrain 11 is cold, heat is absorbed by the electric powertrain 11 itself to increase its temperature, and the heat does not contribute to increasing the temperature of the battery 10. Therefore, in the second mode, the battery 10 does not warm up easily and energy efficiency is poor during the period from the start of warm-up until the electric powertrain 11 warms up.

[0083] Therefore, in this embodiment, the warm-up mode is switched as follows from the viewpoint of warm-up speed or energy efficiency.

[0084] 6A and 6B are graphs showing the switching of the warm-up mode in the warm-up speed priority setting. Fig. 6A shows the transition of the heat quantity when the warm-up mode is switched with the warm-up speed as the priority. In Fig. 6A, the heat quantity Q １ and transported heat quantity Q ２ The second mode efficiency E is shown by a dashed double-dashed line, and the actual amount of heat received by the battery 10 and contributing to warm-up (hereinafter referred to as the received heat amount Q) is shown by a solid line. FIG. 6B shows the transition of energy efficiency when the warm-up mode is switched with priority given to the warm-up speed. In FIG. 6B, the first mode efficiency E １ and second mode efficiency E ２ is shown by a two-dot chain line, and the actual energy efficiency E in the warm-up speed priority setting is shown by a solid line.

[0085] As shown in FIG. 6A, in the warm-up speed priority setting, the amount of heat (heat generation amount Q １ and transported heat quantity Q ２ ) as a reference, the warm-up mode is switched. That is, after the warm-up is started in the first mode, the transport heat quantity Q ２ is the heat generation amount Q in the first mode １ At time t １ At this time, the warm-up mode is switched to the second mode.

[0086] More specifically, when the warm-up of the battery 10 is started in the first mode, the heat generation amount Q １ In the first mode, the battery current I ｂａｔ Since current is applied to the electric powertrain 11 to generate the heat, the electric powertrain 11 also generates heat. For simplicity, it is assumed here that the heat generated by the electric powertrain 11 in the first mode is the same as the heat generated by the electric powertrain 11 in the second mode. Therefore, the transported heat quantity Q ２ As in the case where warm-up of the battery 10 is started in the second mode, the voltage Vcc increases with time, and reaches a value of t １ , the transported heat quantity Q２ is the heat generation amount Q １ Therefore, at time t １ At time t, the warm-up mode is switched from the first mode to the second mode. １ After this, the amount of heat Q received by the battery 10 becomes higher than when the first mode is continued. １ The target temperature (lower limit θ ｍｉｎ ) to reach

[0087] On the other hand, as shown in FIG. 6B, the energy efficiency E is changed from the warm-up mode to the warm-up mode at time t １ Therefore, the warm-up speed priority setting is １ and transported heat quantity Q ２ (i.e., the amount of heat received Q) is used as the criterion for switching the warm-up mode, so that the energy efficiency E of the warm-up control is maintained high and the power consumption of the battery 10 is suppressed. １ This setting prioritizes quickly increasing the temperature.

[0088] However, even with the warm-up speed priority setting, the energy efficiency E is ultimately the first mode efficiency E １ Therefore, the battery temperature θ １ The overall energy efficiency (for example, the integral value of the energy efficiency E) until the battery temperature θ reaches the target temperature is １ That is, according to the warm-up speed priority setting, the battery temperature θ １ This allows the engine to reach the target temperature particularly quickly, and also improves the energy efficiency of warm-up.

[0089] 7A and 7B are graphs showing the switching of the warm-up mode in the efficiency-priority setting. FIG. 7A shows the transition of the heat quantity when the warm-up mode is switched to prioritize energy efficiency. In FIG. 7A, the heat quantity Q １ and transported heat quantity Q ２is shown by a two-dot chain line, and the amount of heat Q received by the battery 10 is shown by a solid line. Fig. 7(B) shows the transition of energy efficiency when the warm-up mode is switched to prioritize energy efficiency. In Fig. 7(B), as in Fig. 6(B), the first mode efficiency E １ and second mode efficiency E ２ is shown by a two-dot chain line, and the actual energy efficiency E in the warm-up speed priority setting is shown by a solid line.

[0090] As shown in FIG. 7B, in the efficiency priority setting, the energy efficiency of the warm-up (first mode efficiency E １ and second mode efficiency E ２ ) as a reference, the warm-up mode is switched. That is, after the warm-up is started in the first mode, the second mode efficiency E ２ is the energy efficiency of the first mode, E １ At time t ２ Therefore, in the efficiency priority setting, the warm-up energy efficiency E is at least equal to the first mode efficiency E １ The energy efficiency E is maintained at or above the above level, and the energy efficiency E is further improved by switching to the warm-up mode.

[0091] On the other hand, in the efficiency priority setting, the switching of the warm-up mode is delayed compared to the warm-up speed priority setting. Specifically, as shown in FIG. 7A, in the warm-up speed priority setting, the switching of the warm-up mode is delayed at time t １ The warm-up mode is switched to the second mode at time t ２ is slower than this.

[0092] Therefore, the efficiency priority setting is the first mode efficiency E １ and second mode efficiency E ２ (i.e., energy efficiency E) is used as the criterion for switching the warm-up mode. １ This setting prioritizes maintaining a high energy efficiency E of the warm-up control over quickly increasing the temperature.

[0093] However, even in the efficiency priority setting, the amount of heat received Q is roughly the same as the amount of heat generated Q １ Therefore, the battery temperature θ １The battery temperature θ １ In other words, according to the efficiency-priority setting, the energy efficiency E of the warm-up is particularly improved, and the battery temperature θ １ can reach the target temperature quickly.

[0094] 8 is a flowchart relating to switching of the warm-up mode. As shown in FIG. 8, in this embodiment, warm-up of the battery 10 is started in the first mode in step S10. In step S11, the state detection unit 41 detects the SOC of the battery 10, the battery temperature θ １ , and ePT temperature θ ２ In step S12, the warm-up control unit 43 acquires the SOC of the battery 10, the battery temperature θ １ , and ePT temperature θ ２ Based on this, the calorific value Q １ , first mode efficiency E １ , transported heat quantity Q ２ , and the second mode efficiency E ２ Calculate the following.

[0095] Thereafter, the warm-up control unit 43 determines whether to switch the warm-up mode in accordance with the setting, and switches the warm-up mode to the second mode. Specifically, if the setting for determining whether to switch the warm-up mode is the warm-up speed priority setting in step S13, the process proceeds to step S14, and the warm-up control unit 43 determines whether to switch the warm-up mode to the second mode. １ and transported heat quantity Q ２ In step S14, the transported heat quantity Q ２ is the heat generation amount Q １ If the amount of transported heat Q is equal to or greater than the predetermined value, the process proceeds to step S16, where the warm-up control unit 43 switches the warm-up mode to the second mode. ２ is the heat generation amount Q １ While the temperature is less than 100°C, the warm-up mode is maintained in the first mode.

[0096] On the other hand, if the setting related to the warm-up mode switching determination is the efficiency priority setting in step S13, the process proceeds to step S15, and the warm-up control unit 43 determines the first mode efficiency E１ and the second mode efficiency E ２ In step S15, the second mode efficiency E ２ is the first mode efficiency E １ If the second mode efficiency E is equal to or greater than the first mode efficiency E, the process proceeds to step S16, where the warm-up control unit 43 switches the warm-up mode to the second mode. ２ is the first mode efficiency E １ While the temperature is less than 100°C, the warm-up mode is maintained in the first mode.

[0097] As mentioned above, the battery temperature θ １ is the predetermined target temperature (lower limit θ ｍｉｎ By switching the warm-up mode before the battery reaches the predetermined temperature, the battery 10 is warmed up faster and more energy efficiently than when the battery 10 is warmed up in either the first or second warm-up mode.

[0098] In the above embodiment, the method of determining whether to switch the warm-up mode is changed depending on whether the warm-up speed priority setting or the efficiency speed priority setting is selected, but this is not limiting. The electric vehicle 100 may be implemented with only one of the warm-up mode switching methods, either the warm-up speed priority setting or the efficiency priority setting. In this case, the warm-up control unit 43 determines the heat generation amount Q １ and transported heat quantity Q ２ , or first mode efficiency E １ and second mode efficiency E ２ , only the one to be used needs to be calculated.

[0099] In the above embodiment, the warm-up of the battery 10 is started in the first mode, but this is not limited to this. １ , transported heat quantity Q ２ , first mode efficiency E １ , and the second mode efficiency E ２ balance and the battery temperature θ at the time of starting the warm-up １ and ePT temperature θ ２ In this case, the warm-up of the battery 10 may be started in the second mode depending on the balance between the heat generation amount Q １and transported heat quantity Q ２ (i.e., the amount of heat received Q) as a reference, or the first mode efficiency E １ and second mode efficiency E ２ It is preferable to switch the warm-up mode based on the energy efficiency E. This improves the warm-up speed and the energy efficiency of the warm-up.

[0100] However, in many cases, it is preferable to start warming up the battery 10 in the first mode and then switch the warm-up mode to the second mode, as in the above embodiment. A typical scenario in which warming up the battery 10 is required is when the electric vehicle 100 is about to start from a state in which both the battery 10 and the electric powertrain 11 are cold, or when the heat generation amount Q １ , transported heat quantity Q ２ , first mode efficiency E １ , and the second mode efficiency E ２ The reason for this is that the balance between the above is often as shown in FIGS.

[0101] In the above embodiment, for simplicity, the warm-up mode is switched once, but depending on the actual situation, the warm-up mode may be switched two or more times. In this case, the criterion for switching the warm-up mode is the heat generation amount Q １ and transported heat quantity Q ２ (i.e., the amount of heat received Q), or the first mode efficiency E １ and second mode efficiency E ２ (i.e., energy efficiency E).

[0102] In addition, in the warm-up control of the battery 10 in the above embodiment, the flow path of the heat exchange medium in the heat exchange system 12 is preferably controlled as follows.

[0103] 9 is a flowchart relating to the flow path control of the heat exchange medium. As shown in FIG. 9, when warming up the battery 10, in step S20, the first heat exchange unit 31 and the second heat exchange unit 32 are disconnected from the heat exchange medium cooling unit 33. In addition, in step S21, the first heat exchange unit 31 and the second heat exchange unit 32 are also disconnected from each other. As a result, both the first heat exchange unit 31 and the second heat exchange unit 32 are isolated. Therefore, the heat generated in the battery 10 (total heat amount ΣH １ ) is less likely to be absorbed by the first heat exchange section 31. As a result, the heat generation amount Q １ becomes larger, and the first mode efficiency E １ In addition, the heat generated in the electric powertrain 11 (total heat amount ΣH ２ ) is less likely to be taken away by the second heat exchanger 32. As a result, the electric powertrain 11 warms up quickly.

[0104] Then, in step S22, the warm-up of the battery 10 is started in the first mode. In step S23, the heat generation amount Q １ and transported heat quantity Q ２ or based on the first mode efficiency E １ and second mode efficiency E ２ In step S23, when the condition for switching to the second mode is met, the process proceeds to step S24, where the first heat exchanger 31 and the second heat exchanger 32 are connected. This makes it easier for heat generated in the electric power train 11 to be transported to the battery 10 via the first heat exchanger 31 and the second heat exchanger 32. In other words, the transported heat quantity Q ２ and second mode efficiency E ２ becomes larger.

[0105] In this example, the determination of whether to switch to the warm-up mode is based on the heat generation amount Q when the first heat exchanger 31 and the second heat exchanger 32 are not connected. １ and first mode efficiency E １ and the transported heat quantity Q when the first heat exchange section 31 and the second heat exchange section 32 are connected. ２ and second mode efficiency E ２ and are used.

[0106] As described above, when warming up the battery 10 at least in the second mode, the first heat exchange unit 31 and the second heat exchange unit 32 are connected, and the heat generated in the electric power train 11 is transported to the battery 10 by the heat exchange medium that flows through the first heat exchange unit 31 and the second heat exchange unit 32 in common. The transported heat quantity Q ２ and second mode efficiency E ２ Therefore, in the second mode, the battery 10 is warmed up particularly quickly and efficiently.

[0107] Furthermore, as described above, if the first heat exchanger 31 and the second heat exchanger 32 are disconnected in the first mode and then connected to each other when the warm-up mode is switched to the second mode, the battery 10 can be warmed up quickly and with good energy efficiency. In the first mode, the heat generated in the battery 10 is difficult to dissipate, and in the second mode, the transported heat quantity Q ２ This is because becomes larger.

[0108] 10 is a flowchart relating to the flow path control of a modified example. As shown in FIG. 10 , in step S30, the first heat exchanger 31 and the second heat exchanger 32 are disconnected from the heat exchange medium cooling unit 33. On the other hand, in step S31, the first heat exchanger 31 and the second heat exchanger 32 are connected. That is, in this example, regardless of whether the warm-up mode is the first mode or the second mode, heat is transported between the battery 10 and the electric powertrain 11 via the first heat exchanger 31 and the second heat exchanger 32 from the start of warm-up.

[0109] Then, in step S32, the warm-up of the battery 10 is started in the first mode. １ and transported heat quantity Q ２ or based on the first mode efficiency E １ and second mode efficiency E ２ Then, in step S33, if the condition for switching to the second mode is satisfied, the process proceeds to step S34, where the warm-up mode is switched to the second mode.

[0110] As described above, when the first heat exchange unit 31 and the second heat exchange unit 32 are connected to start warming up the battery 10, heat is transferred between the battery 10 and the electric powertrain 11 via the first heat exchange unit 31 and the second heat exchange unit 32 from the start of warming up. As a result, part of the heat dissipated from the battery 10 in the first mode warms the electric powertrain 11, and the timing of switching to the second mode is advanced. As a result, the battery temperature θ １ reaches the target temperature particularly quickly, and the battery temperature θ １ This particularly improves the energy efficiency required to reach the target temperature.

[0111] Furthermore, in the first mode, a portion of the heat generated in the electric powertrain 11 is transported to the battery 10 due to conduction loss, contributing to a temperature increase in the battery 10. Therefore, in the first mode, the battery 10 is warmed up particularly quickly and efficiently. That is, the warm-up speed and energy efficiency in the first mode are improved.

[0112] 11 is a flowchart relating to the flow path control of the modified example. As shown in FIG. 11, in step S40, the first heat exchanger 31 and the second heat exchanger 32 are disconnected from the heat exchange medium cooler 33. In step S41, the first heat exchanger 31 and the second heat exchanger 32 are also disconnected. Then, in step S42, warm-up of the battery 10 is started in the first mode.

[0113] Thereafter, in step S43, the first heat exchange unit 31 and the second heat exchange unit 32 are connected. That is, in this example, after warm-up of the battery 10 is started in the first mode, the first heat exchange unit 31 and the second heat exchange unit 32 are connected before the warm-up mode is switched to the second mode, and heat transfer between the battery 10 and the electric powertrain 11 is started during the first mode.

[0114] Then, in step S44, the heat generation amount Q １ and transported heat quantity Q ２ or based on the first mode efficiency E １ and second mode efficiency E ２If the condition for switching to the second mode is satisfied in step S44, the process proceeds to step S45, where the warm-up mode is switched to the second mode.

[0115] As described above, if the first heat exchange unit 31 and the second heat exchange unit 32 are connected after starting the warm-up of the battery 10 in the first mode and before switching the warm-up mode from the first mode to the second mode, the advantages of the flow path control of Fig. 9 and the flow path control of the modified example of Fig. 10 can be obtained. That is, the battery 10 is warmed up quickly and with good energy efficiency.

[0116] As described above, the battery warm-up method according to the present embodiment is a method for warming up a battery by detecting the temperature (θ １ ) is a predetermined temperature (θ ｍｉｎ ), or when the temperature of the battery 10 (θ １ ) is at a predetermined temperature (θ ｍｉｎ ) is expected to be lower than the battery temperature. This battery warm-up method warms up the battery 10 in a warm-up mode, in which heat (Q １ ) to warm up the battery 10, and the second mode is to warm up the battery 10 by using the heat (Q ２ ) to warm up the battery. １ ) is at a predetermined temperature (θ ｍｉｎ ), the first mode and the second mode are switched over.

[0117] In this way, the battery temperature θ １ is the predetermined target temperature (lower limit θ ｍｉｎ By switching the warm-up mode before the battery reaches the predetermined temperature, the battery 10 is warmed up faster and more energy efficiently than when the battery 10 is warmed up in either the first or second warm-up mode.

[0118] In the battery warm-up method according to the above embodiment, warm-up of the battery 10 is started in the first mode, and the temperature (θ １) is at a predetermined temperature (θ ｍｉｎ ), the warm-up mode is switched from the first mode to the second mode.

[0119] A typical scenario in which the battery 10 should be warmed up is when the electric vehicle 100 is about to start from a state in which both the battery 10 and the electric power train 11 are cold. １ , transported heat quantity Q ２ , first mode efficiency E １ , and the second mode efficiency E ２ The balance between these two is often as shown in Figures 5 to 7. Therefore, as described above, by starting the warm-up of the battery 10 in the first mode and then switching the warm-up mode to the second mode, the battery 10 is warmed up quickly and with good energy efficiency.

[0120] In the battery warm-up method according to the above embodiment, the heat generation amount Q of the battery 10 in the first mode １ is calculated, and the amount of heat transported Q is the amount of heat transported from the electric power train 11 to the battery 10 in the second mode. ２ Then, the transported heat quantity Q ２ is the heat generation amount Q １ When this condition is met, the warm-up mode is switched from the first mode to the second mode.

[0121] In this way, the heat generation amount Q １ and transported heat quantity Q ２ (i.e., the amount of heat received Q) is used as the criterion for switching the warm-up mode. １ This allows the engine to reach the target temperature particularly quickly, improving the energy efficiency of warm-up.

[0122] In the battery warm-up method according to the above embodiment, the first mode efficiency E １ is calculated, and the second mode efficiency E is the energy efficiency when the electric power train 11 generates heat and the heat is transported from the electric power train 11 to the battery 10 in the second mode. ２ is calculated. Then, the second mode efficiency E ２ is the first mode efficiency E１ When this condition is met, the warm-up mode is switched from the first mode to the second mode.

[0123] In this way, the first mode efficiency E １ and second mode efficiency E ２ (i.e., energy efficiency E) is used as a criterion for switching the warm-up mode, the energy efficiency E of the warm-up can be particularly improved, and the battery temperature θ １ It is also possible to reach the target temperature more quickly.

[0124] In the battery warm-up method according to the above embodiment, when warming up the battery 10 at least in the second mode, the first heat exchange unit 31 that exchanges heat with the battery 10 and the second heat exchange unit 32 that exchanges heat with the electric powertrain 11 are connected, and the heat generated in the electric powertrain 11 is transported to the battery 10 by a medium (heat exchange medium) that flows commonly through the first heat exchange unit 31 and the second heat exchange unit 32.

[0125] In this way, when warming up the battery 10 at least in the second mode, the heat generated in the electric powertrain 11 is transported to the battery 10, thereby warming up the battery 10 particularly quickly and efficiently in the second mode. Furthermore, throughout the entire warm-up process by switching between the first mode and the second mode, the battery 10 is warmed up quickly and energy-efficiently.

[0126] In the battery warm-up method according to the above embodiment, the first heat exchanger 31 and the second heat exchanger 32 can be connected when warm-up of the battery 10 is started.

[0127] In this case, the battery temperature θ １ reaches the target temperature particularly quickly, and the battery temperature θ １ In particular, the energy efficiency until the target temperature is reached is improved. Also, the warm-up speed and energy efficiency in the first mode are improved.

[0128] In the battery warm-up method according to the above embodiment, after starting to warm up the battery 10 in the first mode, the first heat exchanger 31 and the second heat exchanger 32 can be connected before switching the warm-up mode from the first mode to the second mode.

[0129] In this case, the warm-up speed and energy efficiency are improved in the first mode and the second mode. Therefore, throughout the entire warm-up process by switching between the first mode and the second mode, the battery 10 is warmed up quickly and with good energy efficiency.

[0130] In the battery warm-up method according to the above embodiment, in the first mode, energy is stored in the elements (windings 27) included in the electric power train 11 by discharging the battery 10, and the battery 10 is charged with the energy stored in the elements (windings 27). By repeating the discharge and charge, the internal resistance R ｂａｔ This causes the battery 10 itself to generate heat.

[0131] In this way, by utilizing the elements included in the electric powertrain 11, the battery 10 can be warmed up quickly and efficiently without providing any new elements or the like for the first mode.

[0132] In the battery warm-up method according to the above embodiment, in the second mode, a d-axis current I ｄ２ By flowing the electric current, heat is generated in the electric powertrain 11.

[0133] In this way, by using the rotating electrical machine 25, the battery 10 can be warmed up quickly and efficiently without providing any new elements or the like for the second mode.

[0134] In the battery warm-up method according to the above embodiment, the second mode is a mode in which the carrier frequency f ２ The frequency is increased to a value higher than a predetermined frequency for driving the rotating electrical machine 25, thereby causing the inverter 26 to generate heat.

[0135] In this way, the carrier frequency f of the inverter 26 ２ By changing the above, the battery 10 is warmed up quickly and efficiently in the second mode.

[0136] The battery warm-up device according to the above embodiment is configured to warm up the battery 10 that supplies power to the electric power train 11 in the electric vehicle 100. １) is a predetermined temperature (θ ｍｉｎ ), or when the temperature of the battery 10 (θ １ ) is at a predetermined temperature (θ ｍｉｎ ), the battery warm-up device (controller 14) warms up the battery 10 when the temperature of the battery 10 is expected to drop below a predetermined temperature (θ ｍｉｎ ), the first mode and the second mode are switched over.

[0137] In this way, the battery temperature θ １ is the predetermined target temperature (lower limit θ ｍｉｎ By switching the warm-up mode before the battery reaches the predetermined temperature, the battery 10 is warmed up faster and more energy efficiently than when the battery 10 is warmed up in either the first or second warm-up mode.

[0138] The above describes embodiments of the present invention, but the configurations described in the above embodiments and each modified example only show some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

Claims

1. 1. A battery warm-up method for an electric vehicle, comprising the steps of: warming up a battery that supplies power to an electric powertrain when the temperature of the battery is lower than a predetermined temperature or when the temperature of the battery is expected to become lower than the predetermined temperature, the method comprising: a first warm-up mode for warming up the battery by heat generated in the battery itself, and a second warm-up mode for warming up the battery by heat generated in the electric powertrain; switching between the first mode and the second mode when the electric power train is warmed up before the temperature of the battery reaches the predetermined temperature after the start of warm-up; Battery warm-up method.

2. 2. The battery warm-up method according to claim 1, Initiating a warm-up of the battery in the first mode; switching the warm-up mode from the first mode to the second mode before the temperature of the battery reaches the predetermined temperature; Battery warm-up method.

3. 3. The battery warm-up method according to claim 2, Calculating the amount of heat generated by the battery in the first mode; Calculating a transported heat amount, which is a heat amount transported from the electric power train to the battery, in the second mode; When the amount of transported heat becomes equal to or greater than the amount of heat generated, the warm-up mode is switched from the first mode to the second mode. Battery warm-up method.

4. 3. The battery warm-up method according to claim 2, Calculating a first mode efficiency, which is an energy efficiency when the battery itself is heated in the first mode; causing the electric powertrain to generate heat in the second mode, and calculating a second mode efficiency which is an energy efficiency when transporting the heat from the electric powertrain to the battery; When the second mode efficiency becomes equal to or greater than the first mode efficiency, the warm-up mode is switched from the first mode to the second mode. Battery warm-up method.

5. 5. A battery warm-up method according to claim 1, further comprising: a first heat exchange unit that exchanges heat with the battery and a second heat exchange unit that exchanges heat with the electric power train are connected to each other at least when the battery is warmed up in the second mode; Heat generated in the electric powertrain is transported to the battery by a medium that commonly flows through the first heat exchange unit and the second heat exchange unit. Battery warm-up method.

6. 6. A battery warm-up method according to claim 5, comprising: connecting the first heat exchange unit and the second heat exchange unit when starting to warm up the battery; Battery warm-up method.

7. 6. A battery warm-up method according to claim 5, comprising: after starting warm-up of the battery in the first mode, and before switching the warm-up mode from the first mode to the second mode, connecting the first heat exchange unit and the second heat exchange unit; Battery warm-up method.

8. 2. The battery warm-up method according to claim 1, In the first mode, energy is stored in an element included in the electric power train by discharging the battery, the battery is charged by the energy stored in the element, and the discharging and charging are repeated, whereby heat is generated in the battery itself by an internal resistance of the battery. Battery warm-up method.

9. 2. The battery warm-up method according to claim 1, In the second mode, a d-axis current is caused to flow through a rotating electric machine included in the electric powertrain, thereby generating heat in the electric powertrain. Battery warm-up method.

10. 10. A battery warm-up method according to claim 9, comprising: In the second mode, a carrier frequency used in an inverter that drives the rotating electric machine is increased to be higher than a predetermined frequency that is set in advance for driving the rotating electric machine, thereby generating heat in the inverter. Battery warm-up method.

11. 1. A battery warm-up device for an electric vehicle, the battery warming-up device warming up a battery that supplies power to an electric powertrain when the temperature of the battery is lower than a predetermined temperature or when the temperature of the battery is expected to be lower than the predetermined temperature, The battery warm-up device includes: a first warm-up mode for warming up the battery by heat generated in the battery itself, and a second warm-up mode for warming up the battery by heat generated in the electric powertrain; switching between the first mode and the second mode when the electric power train is warmed up before the temperature of the battery reaches the predetermined temperature after the start of warm-up; Battery warming device.