Charging control method and charging control device

Abstract

Provided is a charging control method in which, in a vehicle equipped with an electric motor unit including a motor and an inverter, and a high-power battery for supplying power to the electric motor unit, the high-power battery is warmed up by heat generated by applying a current to the electric motor unit before or in parallel with charging from an external charging facility to the high-power battery by step-up charging via the electric motor unit. In this charging control method, when warm-up is started and the upper limit current that can be received by the high-power battery is a prescribed value or lower, a relay disposed between the electric motor unit and the high-power battery is opened to cut off electrical connection between the electric motor unit and the high-power battery, and a current is applied from the external charging facility to the electric motor unit. In particular, the current applied to the electric motor unit is made larger than the current applied to the electric motor unit when the upper limit current is applied to the high-power battery while the relay is closed.

Description

Charging control method and charging control device

[0001] The present invention relates to a charge control method and a charge control device for charging an on-board battery from a predetermined external charging facility.

[0002] JP2021-175363A proposes a charging control method for charging an on-board battery using an external charging facility. In particular, this charging control method supplies boosted charging power from the external charging facility to the battery via a motor drive system (inverter and motor) based on the voltage state of the vehicle battery.

[0003] When charging begins with a low battery temperature, such as when a vehicle has been left in a low-temperature environment for a certain period of time, it is desirable to quickly raise the battery temperature to an appropriate charging temperature. To accelerate this battery warm-up, a control method is envisioned that recovers waste heat generated by passing current through the inverter and motor during charging to warm up the battery. However, because the battery can only pass current up to its electrodeposition limit corresponding to its temperature, the current passed through the inverter and motor must be limited, resulting in a problem of insufficient warm-up effect.

[0004] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to further improve the efficiency of warming up an in-vehicle battery when the battery is being charged using an external charging facility.

[0005] According to one aspect of the present invention, in a vehicle equipped with an electric motor unit including a motor and an inverter, and a high-power battery that supplies power to the electric motor unit, a charging control method is provided in which the high-power battery is warmed up by heat generated by passing current through the electric motor unit before or in parallel with charging the high-power battery by boost charging from an external charging facility via the electric motor unit.

[0006] In this charging control method, when warm-up begins, if the upper limit current based on the electrodeposition limit of the high-power battery falls below a predetermined value, a relay arranged between the electric motor unit and the high-power battery is opened to cut off the electrical connection between them, and current is passed from the external charging equipment to the electric motor unit.

[0007] Fig. 1 is a block diagram showing the configuration of an on-board charging system in which a charge control method according to an embodiment of the present invention is executed. Fig. 2 is a flowchart illustrating each process in the charge control method. Fig. 3 is a flowchart illustrating details of a first warm-up process. Fig. 4 is a flowchart illustrating details of a second warm-up process.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0009] 1 is a block diagram showing the configuration of a charging system 100 for implementing the charging control method of this embodiment. Specifically, the charging system 100 includes a high-power battery 1, an inverter 2, a motor 3, an external charging terminal 6, a current sensor 7, capacitors 8 and 11, a DC / DC converter 13, a low-power battery 15, relays R1, R2, R3, R4, and R5, and a controller 20.

[0010] That is, the charging system 100 of this embodiment is configured using elements of an electric vehicle drive system that uses a high-power battery 1 as a power source and drives a motor 3 via an inverter 2. The charging system 100 is mounted on, for example, an electric vehicle (EV) or a plug-in hybrid vehicle (PHEV). In the following description, each of these vehicles will be referred to as an electric vehicle 200.

[0011] In particular, the charging system 100 not only drives the motor 3, but also functions as a system that uses the inverter 2 as a power factor correction circuit (PFC) when the high-power battery 1 is charged by an external charging facility 5. For this reason, the charging system 100 includes an external charging terminal 6 that is a connection terminal for connecting the external charging facility 5. The external charging facility 5 is configured, for example, by a charger disposed in a predetermined charging station and communication devices for communicating various information for charging with the electric vehicle 200.

[0012] 1 shows the configuration of charging system 100 assuming a case where charging is performed using external charging equipment 5 that supplies DC power. However, by appropriately changing the circuit configuration, a system may be configured in which an external charger that supplies AC power is also provided.

[0013] The high-power battery 1 is a DC power supply that functions as a drive power source for the motor 3. For example, the high-power battery 1 is configured as an in-vehicle high-voltage battery (driving battery) such as a lithium-ion secondary battery.

[0014] The inverter 2 is a power conversion device that, when driving the motor 3, converts the DC power output from the high-power battery 1 into AC power and supplies it to the motor 3. More specifically, the inverter 2 is a power conversion device that includes power modules 10u to 10w for driving the motor.

[0015] Each of the power modules 10u to 10w includes a plurality of legs, each consisting of a pair of arms, provided corresponding to each phase of the motor 3. More specifically, the U-phase power module 10u is connected to the U-phase of the motor 3 and includes an upper arm consisting of a U-phase switching element Tr1 and a U-phase freewheel diode D1, and a lower arm consisting of a U-phase switching element Tr2 and a U-phase freewheel diode D2. Similarly, the V-phase power module 10v is connected to the V-phase of the motor 3 and includes an upper arm consisting of a V-phase switching element Tr3 and a V-phase freewheel diode D3, and a lower arm consisting of a V-phase switching element Tr4 and a V-phase freewheel diode D4. The V-phase power module 10v is further connected to the W-phase of the motor 3 and includes an upper arm consisting of a W-phase switching element Tr5 and a W-phase freewheel diode D5, and a lower arm consisting of a W-phase switching element Tr6 and a W-phase freewheel diode D6. Each of the switching elements Tr1 to Tr6 is configured by a power semiconductor element such as an IGBT (Insulated Gate Bipolar Transistor) or a MOS-FET.

[0016] In particular, in a drive mode in which the inverter 2 drives the motor 3, the inverter 2 executes pulse width modulation (PWM) control of each of the switching elements Tr1 to Tr6 based on a power command value determined according to a desired motor torque command value. In this way, energy for driving the motor 3 flows from the high-power battery 1 to the motor 3.

[0017] On the other hand, during charging by the external charging equipment 5, the inverter 2 adjusts the power supplied (input) from the external charging equipment 5 to the external charging terminal 6 to a desired step-up ratio (including a step-up ratio of 1) by switching operations of each switching element Tr1 to Tr6, and supplies the adjusted power to the high-power battery 1.

[0018] During charging by the external charging facility 5, power is fed from the neutral point N of the motor 3 to the inverter 2. At this time, two switching elements (e.g., switching elements Tr1 and Tr2) included in one leg of the inverter 2 and a coil in the motor 3 having one end connected to the connection node of these two switching elements Tr1 and Tr2 constitute a DC converter circuit that boosts the voltage at the neutral point N and supplies it to the inverter side. The same applies to the other two switching elements Tr3 and Tr4, and Tr5 and Tr6.

[0019] Therefore, the connection structure of the inverter 2 and the coils in the motor 3 corresponds to a total of three converter circuits connected in parallel, and by controlling each switching element Tr1 to Tr6 to operate these multiple parallel-connected DC converters simultaneously, selectively, or in an interleaved manner, the voltage at the neutral point N of the motor 3 can be boosted at a predetermined boost ratio and provided to the high-voltage battery 1.

[0020] The motor 3 is configured by a three-phase synchronous motor or the like, and functions as a driving source for the electric vehicle 200. In this embodiment, a unit made up of the inverter 2 and the motor 3 is referred to as an "electric motor unit E."

[0021] The current sensor 7 is a sensor for measuring the current values ​​at three of the four terminals, and outputs the measured current values ​​to the controller 20 .

[0022] The capacitor 8 is connected in parallel to the external charging facility 5 in order to stabilize the potential of the neutral point N of the motor 3 .

[0023] The capacitor 11 is a smoothing capacitor that smoothes the DC power obtained by rectifying the DC power input from the external charging equipment 5 using the power modules 10u to 10w. The capacitor 11 is connected between the power modules 10u to 10w and the high-power battery 1 and in parallel with them.

[0024] The DC / DC converter 13 converts (boosts or reduces) the DC power exchanged between the high-power battery 1 and the low-power battery 15 or the controller 20 .

[0025] The low-power battery 15 is a battery (typically a battery with an operating voltage of 12.5 to 14 V) for supplying power to low-power auxiliary devices mounted on the electric vehicle 200 .

[0026] The controller 20 is configured by a computer that controls each part of the charging system 100 based on various programs stored in a storage unit (not shown). The vehicle ECU (Electronic Control Unit) of the electric vehicle 200 may be used as the controller 20, or an on-board processing device different from the vehicle ECU may be used as the controller 20.

[0027] In particular, when the controller 20 detects a signal indicating a request for the external charging equipment 5 to start charging (such as a signal detecting the insertion of a charging gun or a signal operating a specified charging start switch), it sets either the first charging path or the second charging path described below as the power supply path (charging path) from the external charging equipment 5 to the high-power battery 1, and commands the external charging equipment 5 to supply the desired power (external charging power).

[0028] The first charging path is a power path that supplies external charging power to the high-power battery 1 via a boosting element (inverter 2 and motor 3) that can boost the voltage at a predetermined boost ratio. On the other hand, the second charging path is a power path that supplies external charging power directly to the high-power battery 1, bypassing the inverter 2 and motor 3.

[0029] The relays R4 and R5 are provided between the electric motor unit E and the high-power battery 1 and switch the electrical connection between them on and off. In particular, the relays R4 and R5 in this embodiment are closed (on) during the execution of a charging process including warm-up, except during the execution of a first warm-up process described below, and are opened (off) during the execution of the first warm-up process.

[0030] The controller 20 switches between the first charging path and the second charging path by opening and closing relays R1, R2, R3, and R6. More specifically, when setting the first charging path as the charging path, the controller 20 opens relays R1 and R2 and closes relays R3 and R6. On the other hand, when setting the second charging path as the charging path, the controller 20 closes relays R1 and R2 and opens relays R3 and R6. Hereinafter, charging performed using the first charging path will be referred to as "boost charging," and charging performed using the second charging path will be referred to as "direct charging."

[0031] Furthermore, when the controller 20 receives a request to start charging, it determines whether or not warming up (warming up process) of the high-power battery 1 is required. The warming up process of the high-power battery 1 is a process of warming up the high-power battery 1 to a desired temperature (hereinafter referred to as "warm-up target temperature T") when charging is performed, for example, after the electric vehicle 200 has been left in a low-temperature environment for a certain period of time or more. ｂ_ｔｈ This is a process in which the temperature is raised to the temperature (referred to as "temperature rise").

[0032] When the controller 20 determines that warm-up is required, it executes a warm-up process for the high-power battery 1 before or in parallel with charging the high-power battery 1. Here, in the charging system 100 having the above configuration, as one aspect of the warm-up process, the controller 20 maintains the q-axis current of the motor 3 at zero to prevent motor torque from being generated, while adjusting the d-axis current to a desired value to promote heat generation in the electric motor unit E.

[0033] This allows the high-power battery 1 to be warmed up by utilizing the heat generated by the inverter 2 and the motor 3. Meanwhile, in the warm-up process, current flows through the electric motor unit E, which also causes current to flow through the high-power battery 1 electrically connected to the electric motor unit E. However, during warm-up, the temperature of the high-power battery 1 (battery temperature T ｂ ) is also low, there is a concern that if the current flowing through the high-power battery 1 exceeds a certain value (electrodeposition limit), irreversible deposition of Li metal will occur at the negative electrode of the high-power battery 1. Therefore, in order to prevent the high-power battery 1 from exceeding the electrodeposition limit, the current flowing through the motor unit E must also be reduced, and a sufficient warm-up effect will not be obtained.

[0034] In response to the above problem, the inventors have proposed a method for detecting the battery temperature T ｂ is low and the electrodeposition limit is easily reached (especially, the upper limit current i of the high-power battery 1, which indicates the electrodeposition limit, ｂｕｐ [T ｂ_ｄ ] becomes a certain value or less), the relays R4 and R5 provided between the electric motor unit E and the high-voltage battery 1 are cut off to cut off the power supply to the high-voltage battery 1, and the current flowing to the electric motor unit E is increased, thereby accelerating the warm-up.

[0035] The above charge control method will be described in detail below.

[0036] 2 is a flowchart illustrating the charge control method of this embodiment. Each process in FIG. 2 is started when the controller 20 receives a signal indicating a request to start charging.

[0037] In this charging control method, in step S100, the controller 20 ｂ The measured value of the battery temperature T ｂ_ｄ１ The controller 20 acquires the battery temperature measurement value T ｂ_ｄ１ Get.

[0038] In step S110, the controller 20 calculates the acquired battery temperature measurement value T ｂ_ｄ１ More specifically, the controller 20 determines whether or not warm-up processing is required for the high-power battery 1 based on the battery temperature measurement value T ｂ_ｄ１ is the predetermined warm-up target temperature T ｂ_ｔｈ If it is less than this, it is determined that warm-up processing is necessary, and if it is not, it is determined that warm-up processing is not necessary.

[0039] If the controller 20 determines that the warm-up process is not necessary, it executes the normal charging process (step S160) without the warm-up process. On the other hand, if the controller 20 determines that the warm-up process is necessary, it executes the process from step S120 onwards.

[0040] In step S120, the controller 20 calculates the battery temperature measurement value T ｂ_ｄ１ From the above, the upper limit current i of the high-power battery 1 ｂｕｐ [T ｂ_ｄ１ ] (S120). More specifically, the controller 20 calculates the battery temperature T ｂａ and upper limit current i ｂｕｐ [T ｂ ], and referring to a predetermined battery temperature-upper limit current map that defines the relationship between the battery temperature measurement value T ｂ_ｄ１ From the upper limit current i ｂｕｐ [T ｂ_ｄ１ ] is calculated.

[0041] In step S130, the controller 20 calculates the upper limit current i ｂｕｐ [T ｂ_ｄ１ ] and a predetermined current interruption determination value i ｔｈ１ The magnitudes of and are compared. ｔｈ１ is the upper limit current i to the extent that there is a risk that the high-power battery 1 will exceed its electrodeposition limit when a current for obtaining a desired warm-up effect is passed through the motor unit E in a state where the electrical connection between the motor unit E and the high-power battery 1 is secured (relays R4 and R5 are closed). ｂｕｐ [T ｂ_ｄ１ ] is set to an appropriate value from the viewpoint of determining whether it is small.

[0042] Then, the controller 20 determines the upper limit current i ｂｕｐ[T ｂ_ｄ１ ] is the current interruption determination value i ｔｈ１ If the current interruption determination value i is equal to or less than the threshold value i, the first warm-up process is executed in step S140. ｔｈ１ If the temperature exceeds the threshold, the first warm-up process is skipped and the second warm-up process is executed in step S140.

[0043] 3 is a flowchart showing the details of the first warm-up process. As shown in the figure, in the first warm-up process, in step S141, the controller 20 closes relays R3 and R6 and opens relays R1, R2, R4, and R5 shown in FIG. 1. This breaks the electrical connection between the electric motor unit E and the high-power battery 1, and the electrical connection between the external charging facility 5 and the high-power battery 1.

[0044] Then, in step S142, the controller 20 warms up the high-power battery 1 by passing a desired current through the electric motor unit E. More specifically, the controller 20 adjusts the magnitude of the current input from the external charging equipment 5 to the electric motor unit E (particularly the neutral point N of the motor 3) via communication to a desired value. The controller 20 also switches the inverter 2 so that the magnitude of the current flowing through each phase U, V, W of the motor 3 is uniform.

[0045] In particular, at this time, the current flowing through the motor unit E is set to the upper limit current i when the current of the high-power battery 1 is equal to or exceeds the upper limit current i while the relays R4 and R5 are closed. ｂｕｐ [T ｂ_ｄ１ ]. ｂｕｐ [T ｂ_ｄ１ The current of the motor unit E when the current reaches the maximum value of [V] can be determined in advance by experiment or simulation.

[0046] Furthermore, the current flowing through the motor unit E is adjusted so that the motor unit E does not exceed its heat resistance limit. In particular, the heat resistance limit of the motor unit E is determined by the temperature of the motor unit E (motor unit temperature T ｅ ) measurement value (electric motor unit temperature measurement value T ｅ_ｄ More specifically, the controller 20 estimates the motor unit temperature Tｅ , current, and the heat resistance limit, and the measured value of the electric motor unit temperature T ｅ_ｄ The maximum current within the range that does not exceed the heat resistance limit is determined from the heat resistance limit map, and the current flowing through the electric motor unit E is limited to the maximum current or less. The heat resistance limit map can be determined in advance by experiment or simulation. This allows the electric motor unit temperature measurement value T ｅ_ｄ While monitoring the transition of the heat resistance limit, it is possible to pass as large a current as possible through the motor unit E within a range that does not exceed the heat resistance limit.

[0047] In step S143, the controller 20 supplies power from the low-power battery 15 to the accessories of the electric vehicle 200 (particularly, the controller 20 itself).

[0048] In step S144, the controller 20 again calculates the battery temperature T ｂ The measured value of the battery temperature (hereinafter referred to as the "battery temperature measurement value T ｂ_ｄ２ ").

[0049] In step S145, the controller 20 calculates the acquired battery temperature measurement value T ｂ_ｄ２ Then, referring to the temperature-upper limit current map used in step S120, the upper limit current i of the high-power battery 1 is calculated in the same way. ｂｕｐ [T ｂ_ｄ２ ] is calculated.

[0050] In step S146, the controller 20 calculates the upper limit current i ｂｕｐ [T ｂ_ｄ２ ] and a predetermined limit relaxation judgment value i ｔｈ２ The magnitudes of and are compared. Note that the limit relaxation judgment value i ｔｈ２ is set to a value that is low enough that the high-power battery 1 is unlikely to exceed its electrodeposition limit even when a current for obtaining a desired warm-up effect is passed through the motor unit E while the electrical connection between the motor unit E and the high-power battery 1 is secured (relays R4 and R5 are closed), and that the effect of a decrease in charging efficiency becomes significant if the supply of power to the high-power battery 1 is continued to be stopped (charging is stopped). ｂｕｐ [T ｂ_ｄ２] is set to an appropriate value from the viewpoint of determining whether it is a high value.

[0051] Then, the controller 20 determines the upper limit current i ｂｕｐ [T ｂ_ｄ２ ] is the limit relaxation judgment value i ｔｈ２ If this occurs, the first warm-up process is terminated and the second warm-up process (step S150) is executed.

[0052] 4 is a flowchart showing the details of the second warm-up process. In the second warm-up process, in step S151, the controller 20 closes relays R3, R4, R5, and R6 shown in FIG. 1 and opens relays R1 and R2. This ensures electrical connection between the electric motor unit E and the high-power battery 1, and in particular, electrical connection of the high-power battery 1 to the external charging facility 5 via the electric motor unit E.

[0053] In step S152, the controller 20 again calculates the battery temperature T ｂ The measured value of the battery temperature (hereinafter referred to as the "battery temperature measurement value T ｂ_ｄ３ ").

[0054] In step S153, the controller 20 calculates the acquired battery temperature measurement value T ｂ_ｄ３ Then, referring to the temperature-upper limit current map used in step S120, the upper limit current i of the high-power battery 1 is calculated in the same way. ｂｕｐ [T ｂ_ｄ３ ] is calculated.

[0055] In step S154, the controller 20 calculates the upper limit current i ｂｕｐ [T ｂ_ｄ３ ], determines the current (charging current) to be supplied to the high-power battery 1, and performs charging based on the charging current. More specifically, the controller 20 determines the upper limit current i ｂｕｐ [T ｂ_ｄ３] to a desired charging target current not exceeding the external charging power input from the external charging facility 5, and switches the inverter 2 so that the charging current becomes the charging target current according to the external charging power input from the external charging facility 5. The controller 20 also switches the inverter 2 so that the magnitude of the current flowing through each phase U, V, W of the motor 3 becomes uneven. That is, in step S142, the controller 20 switches from a state in which the magnitude of the current flowing through each phase U, V, W of the motor 3 is uniform to a state in which the magnitude of the current becomes uneven.

[0056] As a result, in the second warm-up process, the high-power battery 1 is charged, and at the same time, the high-power battery 1 can be warmed up using the heat (waste heat) generated by the current flowing through the motor unit E during charging.

[0057] In step S155, the controller 20 supplies power from the high-power battery 1 to the accessories (particularly the controller 20) of the electric vehicle 200. More specifically, the controller 20 reduces the power of the high-power battery 1 using the DC / DC converter 13 and supplies the desired power to the accessories such as the controller 20.

[0058] Furthermore, in step S156, controller 20 corrects the frequency of inverter 2. More specifically, controller 20 adjusts the frequency of inverter 2 to a corrected frequency that is higher than a predetermined fundamental frequency (specified frequency), thereby increasing the amount of heat generated by electric vehicle 200. Note that it is preferable to set the corrected frequency to a value that is as high as possible within a range in which the element temperature of inverter 2 is equal to or lower than the heat resistance limit of the element temperature.

[0059] Then, in step S157, the controller 20 determines whether the warm-up has been completed. More specifically, the controller 20 determines whether the battery temperature T ｂ The battery temperature T ｂ is the warm-up target temperature T ｂ_ｔｈ When the above conditions are met, it is determined that the warm-up is complete. Furthermore, when it is determined that the warm-up is complete, the controller 20 executes the normal charging process (step S160).

[0060] In particular, during normal charging, the controller 20 switches the inverter 2 to perform boost charging so that the desired charging is performed on the high-power battery 1. If the frequency of the inverter 2 is set to a correction frequency, it is preferable to return this frequency to the basic frequency when normal charging begins. Furthermore, if the open-circuit voltage of the high-power battery 1 is greater than the maximum charging voltage, direct charging may be performed as appropriate.

[0061] The configuration of the charge control method of the present embodiment described above and the resulting effects will be described.

[0062] According to this embodiment, in a vehicle (electric vehicle 200) equipped with an electric motor unit E including a motor 3 and an inverter 2, and a high-power battery 1 that supplies power to the electric motor unit E, a charging control method is provided in which the high-power battery 1 is warmed up by heat generated by flowing current through the electric motor unit E before or in parallel with charging the high-power battery 1 by boost charging from an external charging facility 5 via the electric motor unit E.

[0063] In this charging control method, when warm-up (Yes in step S110) is started, the upper limit current i based on the electrodeposition limit of the high-power battery 1 is ｂｕｐ [T ｂ ] is a predetermined value (current interruption determination value i ｔｈ１ ) or less, the relays R4 and R5 arranged between the high-power battery 1 and the electric motor unit E are opened to cut off the electrical connection between them, and current is passed from the external charging equipment 5 to the electric motor unit E.

[0064] This allows the battery temperature T ｂ is low, and the upper limit of the current that can be passed without bringing the high-voltage battery 1 to the electrodeposition limit (i.e., the upper limit current i ｂｕｐ [T ｂ] is low, relays R4 and R5 are opened (electrically disconnecting motor unit E from high-power battery 1) to prevent current from flowing to high-power battery 1, allowing current to flow to motor unit E to generate heat. In other words, the current (amount of heat generated) flowing to motor unit E can be adjusted to achieve a desired warm-up effect without being restricted by the electrodeposition limit of high-power battery 1. Therefore, the high-power battery 1 can be warmed up more efficiently using the heat generated by motor unit E, and the total charging time (the time from start to finish of the charging process, including warm-up) can be shortened.

[0065] In particular, in this embodiment, the current flowing through the electric motor unit E is controlled so that the current of the high-power battery 1 is equal to the upper limit current i ｂｕｐ [T ｂ ] is made larger than the current of the motor unit E when it reaches

[0066] This allows the current (heat generation) flowing through the motor unit E to be increased beyond the level at which the high-voltage battery 1 would normally reach its electrodeposition limit (when relays R4 and R5 are closed), thereby further improving the warm-up efficiency.

[0067] In addition, in this embodiment, when the relays R4 and R5 are open, power is supplied to the auxiliary devices (particularly the controller 20) from the low-power battery 15 mounted on the electric vehicle 200.

[0068] As a result, by opening relays R4 and R5 as described above, power is not being supplied (charged) to the high-power battery 1, and even in a situation where the remaining charge of the high-power battery 1 is expected to be low, the power to be temporarily supplied to the auxiliary equipment can be secured using the on-board low-power battery 15.

[0069] Furthermore, in this embodiment, the current flowing through the electric motor unit E is set to the maximum current based on the heat resistance limit of the electric motor unit E.

[0070] This allows the electric motor unit E to be protected from heat even in a low-temperature environment, while allowing as large a current as possible to flow through the electric motor unit E, thereby improving the warm-up efficiency.

[0071] Furthermore, in this embodiment, when current is passed through the electric motor unit E, the magnitude of the current passing through each of the phases U, V, and W of the motor 3 is adjusted to be uniform.

[0072] This prevents the current from being concentrated in a particular phase, causing the winding current of that phase to reach the upper limit of the heat resistance protection, and optimizes the total current (i.e., the amount of heat generated) of each phase U, V, and W, thereby further improving warm-up efficiency.

[0073] Furthermore, in this embodiment, the battery temperature measurement value T ｂ_ｄ１ When the warm-up is started (Yes in step S110), the current flowing through the high-power battery 1 when the relays R4 and R5 are closed becomes the upper limit current i ｂｕｐ [T ｂ_ｄ１ ] or more (step S130 in FIG. 2). ｂｕｐ [T ｂ_ｄ１ ] or more, the relays R4 and R5 are opened (step S141 in FIG. 3), and the upper limit current i ｂｕｐ [T ｂ_ｄ１ ], relays R4 and R5 are closed (step S151 in FIG. 4).

[0074] This makes it possible to selectively execute control (first warm-up process) in which relays R4 and R5 are opened to cut off the power supply to the high-power battery 1 and prioritize warm-up, and control (second warm-up process) in which relays R4 and R5 are closed to execute warm-up in parallel while supplying (charging) power to the high-power battery 1. In other words, a specific control logic is realized for executing appropriate warm-up processes from the perspective of shortening the total charging time while ensuring the reliability of the functions of the high-power battery 1.

[0075] In particular, in this embodiment, when the relays R4 and R5 are opened and the warm-up is being performed, the battery temperature measurement value T ｂ_ｄ２ is acquired again (step S144), and the acquired battery temperature measurement value T ｂ_ｄ２ From the upper limit current i ｂｕｐ [T ｂ_ｄ２ ] is calculated (step S145). ｂｕｐ [T ｂ_ｄ２] is a predetermined limit relaxation judgment value i ｔｈ２ If this is the case (Yes in step S146), relays R4 and R5 are switched to closed state (step S151 in FIG. 4), and charging of the high-power battery 1 is started (step S154).

[0076] This makes it possible to accurately detect a situation in which the high-power battery 1 is unlikely to reach its electrodeposition limit and the warm-up has progressed to the point where continuing to stop the power supply to the high-power battery 1 (stopping charging) would result in a decrease in charging efficiency becoming a problem, and to start charging the high-power battery 1.

[0077] In this embodiment, during charging (after step S154), the battery temperature measurement value T ｂ_ｄ３ is acquired again, and the acquired battery temperature measurement value T ｂ_ｄ３ From the upper limit current i ｂｕｐ [T ｂ_ｄ３ ] is calculated, and the charging current of the high-power battery 1 is set to the upper limit current i ｂｕｐ [T ｂ_ｄ３ ]Set it below.

[0078] As a result, even in a situation where the relays R4 and R5 are closed and the high-power battery 1 is being charged while being warmed up in parallel (i.e., during execution of the second warm-up process), the charging current of the high-power battery 1 is limited to the upper limit current i ｂｕｐ [T ｂ_ｄ３ ]It can be appropriately determined within the following range.

[0079] Furthermore, in this embodiment, during charging, power is supplied from the high-power battery 1 via the DC / DC converter 13 to the accessories (particularly the controller 20 ) mounted on the electric vehicle 200 .

[0080] As a result, in a situation where the start of charging eliminates concerns about the remaining charge of the high-power battery 1, power can be supplied from the high-power battery 1 to auxiliary devices such as the controller 20.

[0081] Furthermore, in this embodiment, the magnitude of the current flowing through each of the phases U, V, and W of the motor 3 is adjusted non-uniformly during charging.

[0082] This makes it possible to suppress the generation of current ripple in the motor 3 or the inverter 2. In particular, during the first warm-up process (when relays R4 and R5 are open), the magnitude of the current flowing through each phase U, V, and W of the motor 3 is made uniform, as described above, thereby increasing the total current flowing through each phase U, V, and W, thereby improving the amount of heat generated by the electric motor unit E. However, if relays R4 and R5 remain closed in this state, there is a concern that current ripple may occur. In contrast, in this embodiment, during control during charging with relays R4 and R5 closed (second warm-up process), the magnitude of the current flowing through each phase U, V, and W is made unequal, thereby suppressing current ripple.

[0083] Furthermore, in this embodiment, during charging, the frequency of the inverter 2 is adjusted to a correction frequency that is higher than the predetermined fundamental frequency, thereby increasing the amount of heat generated by the electric motor unit E.

[0084] As a result, during charging (during the second warm-up process), the fact that the motor unit E has a margin relative to its heat resistance limit can be taken advantage of, and the frequency of the inverter 2 can be increased to increase the amount of heat generated by the motor unit E, thereby promoting warm-up.

[0085] Furthermore, in this embodiment, a controller 20 is provided that functions as a charge control device suitable for executing the above-described charge control method. When warm-up (Yes in step S110) is started, the controller 20 determines an upper limit current i based on the electrodeposition limit of the high-power battery 1. ｂｕｐ [T ｂ ] is a predetermined value (current interruption determination value i ｔｈ１ ) or less, the relays R4 and R5 arranged between the high-power battery 1 and the electric motor unit E are opened to cut off the electrical connection between them, and current is passed from the external charging equipment 5 to the electric motor unit E.

[0086] The processing procedures shown in each of the above-described embodiments are examples for realizing each embodiment, and the order of some of the processing procedures may be changed within the scope that allows each embodiment to be realized, and some of the processing procedures may be omitted or other processing procedures may be added.

[0087] Furthermore, each process shown in each embodiment is executed based on a program for causing a computer to execute each processing procedure, and therefore each embodiment can also be understood as an embodiment of a program that realizes the function of executing each process, or a recording medium that stores the program.

[0088] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

Claims

1. A charging control method for a vehicle equipped with an electric motor unit including a motor and an inverter, and a high-power battery that supplies power to the electric motor unit, in which the high-power battery is warmed up by heat generated by flowing current through the electric motor unit before or in parallel with charging the high-power battery by boost charging from an external charging facility via the electric motor unit, wherein when warm-up begins and an upper limit current based on the electrodeposition limit of the high-power battery falls below a predetermined value, a relay arranged between the electric motor unit and the high-power battery is opened to cut off the electrical connection between them, and current is allowed to flow from the external charging facility to the electric motor unit.

2. A charging control method according to claim 1, wherein the current flowing through the electric motor unit is made larger than the current through the electric motor unit when the current through the high-power battery reaches the upper limit current with the relay closed.

3. A charge control method according to claim 1, wherein, when the relay is open, power is supplied to auxiliary equipment from a low-voltage battery mounted on the vehicle.

4. A charge control method according to claim 1, wherein the current flowing through the electric motor unit is set to a maximum current based on the heat resistance limit of the electric motor unit.

5. A charge control method according to claim 1, wherein when a current is caused to flow through the electric motor unit, the magnitude of the current flowing through each phase of the motor is adjusted to be uniform.

6. A charging control method according to claim 1, comprising the steps of: acquiring a battery temperature measurement value; and, when warm-up is initiated, referring to the acquired battery temperature measurement value, determining whether the current flowing through the high-power battery will be equal to or greater than the upper limit current if the relay is closed; and, if the current flowing through the high-power battery is equal to or greater than the upper limit current, opening the relay; and, if not, closing the relay.

7. A charge control method according to claim 6, comprising the steps of: acquiring the battery temperature measurement value again while the relay is open and warming up is being performed; calculating the upper limit current from the acquired battery temperature measurement value; and closing the relay and commencing charging of the high-power battery when the upper limit current becomes equal to or greater than a predetermined limit relaxation judgment value.

8. A charge control method according to claim 6, comprising the steps of: acquiring the battery temperature measurement value again during charging; calculating the upper limit current from the acquired battery temperature measurement value; and setting the charging current of the high-power battery to a value equal to or lower than the upper limit current.

9. A charge control method according to claim 6, wherein during charging, power is supplied from the high-power battery to auxiliary equipment mounted on the vehicle via a DC / DC converter.

10. A charge control method according to claim 6, wherein the magnitude of the current flowing through each phase of the motor is adjusted non-uniformly during charging.

11. A charge control method according to claim 6, wherein during charging, the frequency of the inverter is adjusted to a correction frequency higher than a predetermined fundamental frequency to increase the amount of heat generated by the electric motor unit.

12. A charging control device for a vehicle equipped with an electric motor unit including a motor and an inverter, and a high-power battery that supplies power to the electric motor unit, which warms up the high-power battery by heat generated by passing current through the electric motor unit before or in parallel with charging the high-power battery by boost charging from an external charging facility via the electric motor unit, wherein when warm-up begins and an upper limit current based on the electrodeposition limit of the high-power battery falls below a predetermined value, the charging control device opens a relay arranged between the electric motor unit and the high-power battery to cut off the electrical connection between them, and allows current to flow from the external charging facility to the electric motor unit.

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