JP2016181384A - Electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress precipitation of lithium metal by not limiting the charging current, superposing a ripple current, unduly but limiting properly, in a vehicle on which a lithium ion secondary battery is mounted.SOLUTION: When the charging current IB of a lithium ion secondary battery exceeds a charging current upper limit Ilim set so that the negative electrode potential of the lithium ion secondary battery does not drop to a lithium reference potential, charging power of the secondary battery is limited. The charging current upper limit Ilim is configured for each control period T0 by reflecting the charge and discharge history of the secondary battery. Even if the charging current average value IBave does not reach the charging current upper limit Ilim, when the charging current IB superposing a ripple current exceeds the charging current upper limit Ilim instantaneously, charging power of the secondary battery is limited only when the frequency of the ripple current is lower than a predetermined frequency.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an electric vehicle, and more particularly to an electric vehicle equipped with a lithium ion secondary battery that inputs and outputs electric power to and from a vehicle driving motor.

  BACKGROUND ART Lithium ion secondary batteries are being applied as in-vehicle power storage devices used in hybrid vehicles, fuel cell vehicles, and electric vehicles that travel with driving force from a traveling motor. A lithium ion secondary battery has a high energy density and a high output voltage, and thus is suitable as an in-vehicle power storage device that requires a large battery capacity and a high voltage. On the other hand, it is known that a lithium ion secondary battery may cause heat generation or performance degradation of the battery due to deposition of lithium metal on the negative electrode surface depending on the usage mode.

  For this reason, International Publication No. 2010/005079 (Patent Document 1) is mounted on a hybrid vehicle based on the charge / discharge history in order to suppress the deposition of lithium metal on the negative electrode of the lithium ion secondary battery. The control for adjusting the input permission power to the battery is described. Specifically, based on the battery current, the maximum current value that can avoid the precipitation of lithium metal due to the decrease in the negative electrode potential of the lithium ion secondary battery to the lithium reference potential is sequentially calculated. It is described that input permission power to the battery is adjusted so as not to exceed the maximum current value.

International Publication No. 2010/005079 JP 2012-105467 A JP 2012-016263 A

  According to the technique of Patent Document 1, when it is determined whether or not the battery current exceeds the maximum current at every constant control cycle, it is difficult to evaluate the battery current on which the ripple current (alternating current) component is superimposed within the control cycle. is there. That is, depending on the setting of the control cycle, it becomes difficult to appropriately limit the input permission power when the battery current instantaneously exceeds the maximum current value within the control cycle due to the superposition of the ripple current. On the other hand, if the input permission power is excessively limited, the energy recovery amount due to regenerative braking in the hybrid vehicle is reduced, so that the energy efficiency is lowered.

  The present invention has been made to solve such a problem, and an object of the present invention is to excessively limit a charging current superimposed with a ripple current in a vehicle equipped with a lithium ion secondary battery. Without restricting appropriately, it is suppressing precipitation of lithium metal.

  In one aspect of the present invention, an electric vehicle manages charge / discharge of a power storage device configured with a lithium ion secondary battery, an electric motor having an output shaft that forms a power transmission path between wheels, and the power storage device. And a control device. The control device includes setting means, first and second limiting means, and detection means. The setting means sets a charging current upper limit value for limiting the input current to the power storage device so that the negative electrode potential of the lithium ion secondary battery does not drop to the lithium reference potential at every predetermined control cycle. The first limiting unit operates every predetermined control cycle, and limits input power to the power storage device when the input current exceeds the charging current upper limit value. The detecting means detects in each control cycle that the input current instantaneously exceeds the charging current upper limit value within the control cycle. The second detection means is input when the input power restriction by the first restriction means is not executed and the detection means detects that the input current instantaneously exceeds the charging current upper limit value. When the frequency of the ripple current superimposed on the current is lower than a predetermined frequency, the input power is limited.

  According to the electric vehicle, the charge current upper limit value (allowable input current value Ilim) is updated at a constant control cycle reflecting the charge / discharge history, and the charge current (battery current) is shorter than the update cycle. By checking IB), it can be detected that the charging current superimposed with the ripple current instantaneously exceeds the input current limit target value. Further, by limiting the input power of the power storage device only when the ripple current is included in the low frequency region, charging of the power storage device can be avoided in the current frequency region that does not affect lithium metal deposition. As a result, it is possible to appropriately limit the charging current on which the ripple current is superimposed without excessively limiting the lithium current, and to suppress the deposition of lithium metal during charging of the lithium ion secondary battery.

  According to the present invention, in a vehicle equipped with a lithium ion secondary battery, the charging current superimposed with the ripple current is appropriately limited without excessively limiting the deposition of lithium metal.

It is a block diagram explaining the structural example of the hybrid vehicle shown as a representative example of the electric vehicle which concerns on embodiment of this invention. It is a block diagram which shows the structure of the electric system of the hybrid vehicle shown in FIG. It is a wave form diagram explaining Li precipitation suppression control performed with the electric vehicle according to embodiment of this invention. It is a flowchart explaining the control process of Li precipitation suppression control performed with the electric vehicle according to embodiment of this invention. It is a conceptual waveform diagram explaining the current behavior when the ripple current is superimposed on the battery current in the Li deposition suppression control. A flowchart illustrating a control process of current check within each control cycle in Li deposition suppression control in the electric vehicle according to the present embodiment is shown.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated in principle.

  FIG. 1 is a block diagram illustrating a configuration example of a hybrid vehicle shown as a representative example of an electric vehicle according to an embodiment of the present invention.

  In the embodiment of the present invention, an “electric vehicle” is a vehicle configured to generate driving force from an electric motor (motor) and rotate driving wheels by electric power supplied from a power supply device. As an example, a hybrid vehicle, an electric vehicle, a fuel cell vehicle, and the like are included.

  Referring to FIG. 1, the hybrid vehicle operates as an engine 100, a first MG (Motor Generator) 200 that mainly operates as a generator, a PCU (Power Control Unit) 300, a battery 400, and mainly as an electric motor. Second MG 500, ECU (Electronic Control Unit) 600, and power split mechanism 700 are included.

  The power generated by the engine 100 is divided into two paths by the power split mechanism 700. One is a path for driving the wheel 900 via the speed reducer 800. The other is a path for driving the first MG 200 to generate power.

  First MG 200 and second MG 500 are typically configured by a three-phase AC motor.

  First MG 200 generates power using the power of engine 100 distributed by power split device 700. The electric power generated by first MG 200 is selectively used according to the driving state of the vehicle and the SOC (State of Charge) of battery 400. For example, during normal traveling or sudden acceleration, the electric power generated by first MG 200 becomes electric power for driving second MG 500 as it is. On the other hand, when the SOC of battery 400 is lower than a predetermined value, the power generated by first MG 200 is converted from AC power to DC power by inverter 302 of PCU 300. This DC power is stored in the battery 400 after the voltage is adjusted by the converter 304. First MG 200 operates as an electric motor for motoring engine 100 when the engine is started.

  Inverter 302 is illustrated as a single block in FIG. 1, but actually inverters are individually arranged corresponding to first MG 200 and second MG 500, respectively. The DC link side of these inverters is connected in common with the converter 304.

  The battery 400 is composed of a lithium ion secondary battery. Generally, as the battery 400, an assembled battery configured by further connecting a plurality of modules in which a plurality of lithium ion battery cells are integrated in series is used.

  The positive electrode of the lithium ion battery cell is made of a material (for example, a lithium-containing oxide) capable of reversibly occluding / releasing lithium ions. The positive electrode releases lithium ions into the electrolyte during the charging process, and occludes lithium ions in the electrolyte released from the negative electrode during the discharging process. The negative electrode of the lithium ion battery cell is made of a material (for example, carbon) capable of reversibly occluding / releasing lithium ions. The negative electrode occludes lithium ions in the electrolytic solution released from the positive electrode during the charging process, and releases lithium ions into the electrolytic solution during the discharging process.

  Second MG 500 is driven by at least one of the electric power stored in battery 400 and the electric power generated by first MG 200. The output shaft (rotor) of second MG 500 is configured to form a power transmission path with wheels 900. Therefore, the driving force of the second MG 500 is transmitted to the wheel 900 via the speed reducer 800. Thus, second MG 500 assists engine 100 to cause the vehicle to travel, or causes the vehicle to travel only by the driving force from second MG 500.

  Furthermore, at the time of regenerative braking of the hybrid vehicle, second MG 500 is driven by wheel 900 via reduction gear 800, and second MG 500 is operated as a generator. Thus, second MG 500 functions as a regenerative brake that converts braking energy into electric power. The electric power generated by second MG 500 is stored in battery 400 via inverter 302.

  ECU 600 includes a CPU (Central Processing Unit) and a memory (not shown). The ECU 600 operates the vehicle, the accelerator opening (ACC) detected by the accelerator opening sensor 1100, the rate of change of the accelerator opening, the vehicle speed (V) detected by a vehicle speed sensor (not shown), the shift position, and the battery 400. The arithmetic processing is performed based on the SOC, a map stored in a memory (not shown), a program, and the like. Thereby, ECU 600 controls the devices mounted on the vehicle so that the vehicle is in a desired driving state. Note that at least a part of the ECU 600 may be configured to execute predetermined numerical / logical operation processing by hardware such as an electronic circuit.

  FIG. 2 is a block diagram showing the configuration of the electric system of the hybrid vehicle shown in FIG.

  Referring to FIG. 2, ECU 600 includes a battery ECU 601 for monitoring battery 400 and an MG-ECU 602 for controlling PCU 300. ECU 600 corresponds to a “control device”.

  Output signals from voltage sensor 610, current sensor 612, and temperature sensor 614 are transmitted to battery ECU 601. Voltage sensor 610 detects the output voltage value of battery 400 (hereinafter also referred to as battery voltage VB). Current sensor 612 detects a charge / discharge current value of battery 400 (hereinafter also referred to as battery current IB). Temperature sensor 614 detects the temperature of battery 400 (hereinafter also referred to as battery temperature TB). In the following description, it is assumed that the battery current has a positive value (IB> 0) when the battery 400 is discharged and the battery current has a negative value (IB <0) when charged.

  Battery ECU 601 calculates the charge / discharge power value of battery 400 from battery voltage VB from voltage sensor 610 and battery current IB from current sensor 612. Furthermore, battery ECU 601 can calculate the SOC of battery 400 by tracing the SOC change based on the integration of battery current IB. It should be noted that other well-known techniques may be used for calculating the SOC, and detailed description thereof will not be repeated here. The history of the battery current IB detected by the current sensor 612 can be stored in a memory (not shown) in the battery ECU 601.

  Further, battery ECU 601 has a charge power upper limit value (hereinafter also referred to as WIN) indicating a limit value of power charged in battery 400 and a discharge power upper limit value (hereinafter also referred to as WOUT) indicating a limit value of power discharged from battery 400. Set). The charging power value for battery 400 and the discharging power value from battery 400 are limited so as not to exceed WIN and WOUT. Note that other well-known techniques may be used as a method of limiting the charging power and discharging power of battery 400, and detailed description thereof will not be repeated here.

  In first MG 200, rotation angle sensor 201 and current sensor 202 are arranged. Similarly, rotation angle sensor 501 and current sensor 502 are arranged in second MG 500. Current sensors 202 and 502 are schematically shown in FIG. 2, but are actually arranged so as to detect three-phase currents supplied from PCU 300 to first MG 200 and second MG 500, respectively.

  MG-ECU 602 receives outputs from rotation angle sensors 201 and 501 and current sensors 202 and 502. MG-ECU 602 can detect the rotation speeds of first MG 200 and second MG 500 based on the outputs from rotation angle sensors 201 and 501. Further, MG-ECU 602 can control the output torques of first MG 200 and second MG 500 based on the rotation angles (rotors) and three-phase currents of first MG 200 and second MG 500.

  MG-ECU 602 controls the operation of PCU 300 such that the outputs of first MG 200 and second MG 500 are controlled according to a command value (for example, a torque command value). Specifically, MG-ECU 602 controls the operations of inverter 302 and converter 304 by feedback control of the currents of first MG 200 and second MG 500 detected by a current sensor (not shown).

  The battery ECU 601 samples data at a constant sampling period (for example, 8 [ms]), and manages the state of the battery 400 at a control period (for example, 100 [ms]) based on the sampled data. The management includes the above-described calculation of SOC and setting of WIN and WOUT.

  On the other hand, MG-ECU 602 generally controls the operation of inverter 302 and converter 304 by PWM (Pulse Width Modulation) control in which the switching frequency is set to several KHz to 10 kHz.

  For this reason, the control cycle and sampling cycle of MG-ECU 602 are shorter than battery ECU 601. Therefore, by inputting the output signal from current sensor 612 to MG-ECU 602, battery current IB can be detected at a cycle shorter than the control cycle of battery ECU 601.

  Next, Li deposition suppression control for battery 400 formed of a lithium ion secondary battery in the electric vehicle according to the embodiment of the present invention will be described.

  The lithium-ion secondary battery constituting the battery 400 has a high energy density and a high initial circuit voltage and average operating voltage as compared with other secondary batteries. Therefore, an in-vehicle power storage device for a vehicle that requires a large battery capacity and high voltage. It is known that it is suitable for. In addition, the lithium ion secondary battery has high charge / discharge efficiency because the Coulomb efficiency is close to 100%, and thus has an advantage that energy can be effectively used compared to other secondary batteries.

  However, as shown in Patent Document 1, lithium ion secondary batteries may deposit lithium metal on the negative electrode surface depending on the charging conditions. For this reason, in the present embodiment, similarly to Patent Document 1, in order to suppress lithium metal deposition in the lithium ion secondary battery, control for limiting charging to the battery 400 (hereinafter referred to as “Li deposition suppression control”) is also performed. Execute).

  FIG. 3 is a waveform diagram illustrating Li precipitation suppression control executed in the electric vehicle according to the embodiment of the present invention.

  Referring to FIG. 3, battery current IB changes in the negative direction from time t0, and charging of battery 400 is started.

  The allowable input current value Ilim of the battery 400 is set according to the charge / discharge history of the battery 400. As described in Patent Document 4, the allowable input current value Ilim is obtained as the maximum current value at which lithium metal does not precipitate when the battery negative electrode potential decreases to the lithium reference potential within a unit time. The allowable input current value Ilim can be set in the same manner as in Patent Document 1. That is, from the initial value Ilim [0] of the allowable input current value in a state where there is no charge / discharge history, by adding / subtracting a decrease amount due to continued charging, a recovery amount due to continued discharge, or a recovery amount due to neglecting for each control cycle, time Ilim [t] at t is sequentially obtained. Since the allowable input current value Ilim indicates the allowable upper limit value of the charging current, Ilim ≦ 0 is set.

  Further, a margin current ΔImr with respect to the allowable input current value Ilim is set to set an input current limit target value Itag for preventing lithium metal deposition. As described in Patent Document 4, the input current limit target value Itag can be set by offsetting the allowable input current value Ilim in the positive direction. In this case, the offset current value becomes the margin current ΔImr. The input current limit target value Itag is also set to Itag ≦ 0.

  As shown in FIG. 3, the allowable input current value Ilim and the input current limit target value Itag gradually change in the positive direction due to continuous charging. As a result, it is understood that the allowable charging current (| IB |) is reduced. When IB exceeds Itag at time t1 (IB <Itag), it is necessary to limit the charging current in order to suppress lithium metal deposition. For example, charging power (that is, regenerative power from second MG 500) is limited by changing WIN of battery 400 in the positive direction from time t1. Hereinafter, the limitation on the charging power of the battery 400 due to the change in WIN is also simply referred to as “WIN” limitation. While the WIN restriction protects the battery 400 by preventing lithium metal deposition, the energy efficiency is lowered due to the restriction of regenerative power generation by the second MG 500.

  Due to the WIN limitation from time t1, the charging current decreases (that is, IB changes in the positive direction), and after time t2, IB> Itag again.

  FIG. 4 is a flowchart illustrating a control process of Li precipitation suppression control executed in the electric vehicle according to the embodiment of the present invention. The control process according to the flowchart shown in FIG. 4 is executed by the battery ECU 601 at a constant control cycle.

  Referring to FIG. 4, battery ECU 601 obtains battery state data (VB, IB, DB) based on the outputs of current sensor 612, voltage sensor 610, and temperature sensor 614 in step S100. Further, battery ECU 601 calculates the SOC of battery 400 in step S110.

  Battery ECU 601 sets WIN0, which is the base value of WIN of battery 400, in step S120. WIN0 is the WIN before executing the Li deposition suppression control, and is set based on the current battery state (SOC, battery temperature, etc.). That is, this WIN 0 corresponds to the WIN of the battery 400 that is normally set based on a known method.

  Furthermore, battery ECU 601 executes a current control calculation for Li deposition suppression control in step S130. That is, as described in FIG. 3, based on the method shown in Patent Document 1, the allowable input current value Ilim [t] in the current control cycle is calculated based on the charge / discharge history of the battery 400. Then, by providing a predetermined margin current ΔImr with respect to the allowable input current value Ilim [t], the “charging current upper limit value” for preventing the negative electrode potential of the lithium ion secondary battery from being lowered to the lithium reference potential is set. A corresponding input current limit target value Itag is calculated. The setting of the input current limit target value Itag in step S130 corresponds to the function of “setting means”.

  Battery ECU 601 receives a current check result within each control cycle from MG-ECU 602 in step S200. As will be described later, the evaluation of the battery current IB within the control cycle is executed by the MG-ECU 602 having a shorter sampling cycle than the battery ECU 601. By checking the battery current IB with the MG-ECU 602, it is possible to detect a charging current (battery current IB) in consideration of an alternating current component (ripple current) having a frequency that is difficult to detect in the control cycle of the battery ECU 610.

  FIG. 5 is a conceptual waveform diagram for explaining the current behavior when the ripple current is superimposed on the battery current IB in the Li deposition suppression control.

  Referring to FIG. 5, a ripple current having a predetermined frequency is superimposed on battery current IB. This ripple current typically has a frequency that depends on the rotational speed of second MG 500 in FIG.

  The input current limit target value Itag is updated based on the charge / discharge history of the battery 400 by executing the flowchart shown in FIG. 4 every predetermined control cycle T0. For example, the input current limit target value Itag is updated at each of the times ta, tb, tc, and td. As described above, the input current limit target value Itag corresponds to a threshold value for determining whether or not the WIN limit is necessary.

  When the ripple current is superimposed on the battery current IB, even if the current average value IBave within the control cycle T0 or the current sampling value for each control cycle T0 does not exceed the input current limit target value Itag, Thus, it is understood that the battery current IB (IB <Itag) exceeding the input current limit target value Itag is generated. However, when the determination is made based on the current average value IBave or the current sampling value for each control cycle T0, it cannot be detected that the battery current IB exceeds the input current limit target value Itag.

  On the other hand, the influence of the ripple current on the lithium metal deposition of the lithium ion secondary battery has frequency dependency. Specifically, the high-frequency ripple current does not affect the charge / discharge history of the lithium ion secondary battery. That is, even if the battery current IB instantaneously exceeds the input current limit target value Itag (IB <Itag) due to the high-frequency ripple current, no adverse effect is caused on the lithium metal deposition. On the other hand, the low-frequency ripple current affects the charge / discharge history of the lithium ion secondary battery. That is, when the battery current IB exceeds the input current limit target value Itag due to the low-frequency ripple current, lithium metal may be deposited. Since the threshold value of the frequency affecting the lithium metal deposition depends on the characteristics of the battery 400, it can be obtained in advance by an actual machine experiment or the like.

  FIG. 6 shows a flowchart illustrating a current check control process within each control cycle of Li deposition suppression control in the electric vehicle according to the present embodiment. As described above, the current check is executed by the MG-ECU 602.

  Referring to FIG. 6, MG-ECU 602 calculates current average value IBave and peak current value IBpk in one cycle (T0) of the control cycle of Li precipitation suppression control in step S210.

  In step S210, the peak current value IBpk may be obtained by the MG-ECU 602 performing statistical processing on the battery current IB sampled at a predetermined sampling period. Alternatively, the battery current IB can be input to a separately provided peak hold circuit (not shown), and the peak current value IBpk can be acquired based on the output of the peak hold circuit.

  In step S220, MG-ECU 602 compares current average value IBave of battery current IB with input current limit target value Itag. If IBave <Itag (YES in S220), the average value of the battery current IB exceeds the input current limit target value Itag, so the process proceeds to step S250. In step S250, MG-ECU 602 sets a restriction flag FLG to 1 in order to turn on the WIN restriction. The WIN restriction by determining YES in step S220 corresponds to the function of “first restriction means”.

  On the other hand, when IBave <Itag (when NO is determined in S220), MG-ECU 602 advances the process to step S230 to determine whether peak current value IBpk of the charging current has reached input current limit target value Itag. Determine further. The determination in step S230 corresponds to the function of “detection means”.

  When IBpk> Itag (NO in S230), neither the average value nor the peak value of the charging current (battery current IB) has reached the allowable input current value Ilim. Therefore, the MG-ECU 602 advances the process to step S260 and sets the restriction flag FLG = 0. That is, the regeneration limit is turned off.

  On the other hand, when IBpk <Itag (when YES is determined in S230), MG-ECU 602, that is, the charging current (battery current IB) superimposed with the ripple current instantaneously exceeds allowable input current value Ilim. In this case, the process proceeds to step S240, and the ripple current frequency frp (hereinafter also referred to as ripple frequency frp) is compared with a predetermined threshold value ft. As described above, threshold value ft is determined in advance corresponding to battery 400.

  In the determination in step S240, the ripple frequency frp can be obtained by calculation from the rotation speed of the second MG 500, for example. Since the battery current IB input / output to / from the battery 400 is used to output the driving force or regenerative braking force by the second MG 500, the electrical frequency according to the reciprocal of the rotational speed of the second MG 500 is the main factor of the ripple current. is there. In this way, it is possible to reduce the calculation load as compared with the process of extracting the frequency component from the battery current sampled by the MG-ECU 602.

  When frp <ft (YES in S240), MG-ECU 602 determines that the frequency of the ripple current is included in the low-frequency region that affects the deposition of lithium metal. Therefore, MG-ECU 602 advances the process to step S250 and sets restriction flag FLG = 1. On the other hand, when frp> ft (NO in S240), the restriction flag FLG = 0 is set in step S260.

  Thereby, even if the average value IBave of the charging current does not reach the allowable input current value Ilim (that is, the WIN limitation by the “first limiting means” is not executed), the peak current value IBpk superimposed with the ripple current is allowable. When it is detected that the input current value Ilim is exceeded and the ripple current frequency is included in a predetermined low frequency region (frp <ft), WIN restriction is performed to avoid lithium metal deposition. Is done. That is, the WIN restriction by determining YES in step S240 corresponds to the function of “second restriction means”.

  Thus, according to the flowchart shown in FIG. 6, MG-ECU 602 sets restriction flag FLG to 1 or 0 based on the current check result for the immediately preceding one cycle. For example, the current check result (that is, the limit flag FLG) received by battery ECU 601 from MG-ECU 602 in step S200 of FIG. 4 at the timing of time t2 in FIG. 5 is the battery current between time t1 and t2 by MG-ECU 602. This is performed by comparing IB with the allowable input current value Ilim at time t1.

  As described above, the determination in step S220 may be performed by comparing the battery current IB with the sampling value for each control cycle T0 and the input current limit target value Itag. In this way, the calculation load related to the determination process can be reduced.

  In the example of FIG. 6, the current check process in steps S220 to S260 is executed by the MG-ECU 602. However, the battery ECU 601 uses the current average value IBave (or sampling value) and the peak current value IBpk acquired in step S210. It is also possible for the battery ECU 601 to execute the current check process.

  Referring to FIG. 4 again, in step S150, battery ECU 601 checks the value of restriction flag FLG received from MG-ECU 602 in step S200. When the battery ECU 601 is FLG = 1 (YES in step S150), the process proceeds to step S160, and the WIN restriction is turned on to suppress lithium metal deposition. That is, in step S170, battery ECU 601 sets final WIN such that the absolute value is smaller than base value WIN0 (| WIN | <| WIN0 |).

  In contrast to this, when FLG = 0 (NO in S150), battery ECU 601 proceeds to step S180 to turn off the WIN restriction. Therefore, battery ECU 601 sets WIN = WIN0 in step S190. That is, when the WIN restriction is turned off, the base value WIN0 based on the SOC of the battery 400 and the battery temperature TB is directly adopted as the final WIN.

  As described above, according to the Li deposition suppression control in the electric vehicle according to the present embodiment, the charging current upper limit value for avoiding the deposition of lithium metal (reflected in a certain control cycle reflecting the charge / discharge history) By checking the charging current (battery current IB) at a cycle shorter than the update cycle of the allowable input current value Ilim), it is detected that the charging current superimposed with the ripple current instantaneously reaches the input current limit target value can do.

  Furthermore, in consideration of the frequency of the ripple current and the characteristics of the lithium ion secondary battery, the WIN limitation is excessively performed by applying the WIN limitation only when the frequency of the ripple current is lower than the predetermined frequency. You can avoid that. As a result, it is possible to appropriately limit the charging current on which the ripple current is superimposed without excessively limiting the lithium current, and to suppress the deposition of lithium metal during charging of the lithium ion secondary battery.

  In the present embodiment, an example has been described in which the Li deposition suppression control is executed by a combination of a plurality of ECUs having different control cycles and sampling cycles (battery ECU 601 and MG-ECU 602), but a single ECU (control device) is used. It is also possible to realize the same control process by executing the control process (subroutine) at different calculation cycles.

  Further, in the application of the present invention, the configuration of the electric vehicle is not limited to the configuration of FIG. That is, a vehicle with an in-vehicle power storage device constituted by a lithium ion secondary battery can be used for a hybrid vehicle having a power tolane configuration different from that shown in FIG. 1 or an electric vehicle other than a hybrid vehicle such as an electric vehicle or a fuel cell vehicle. The present invention can be applied in common as long as it has a configuration for inputting and outputting electric power to and from the drive motor.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  100 Engine, 200 1st MG, 201, 501 Rotation angle sensor (MG), 202, 502 Current sensor (MG), 300 PCU, 302 Inverter, 304 Converter, 400 Battery, 500 2nd MG, 600 ECU, 601 Battery ECU, 602 MG-ECU, 610 Voltage sensor (battery), 612 Current sensor (battery), 614 Temperature sensor (battery), 700 Power split mechanism, 800 Reducer, 900 wheel, 1100 Accelerator opening sensor, FLG limit flag, IB Battery current , IBave current average value (battery current), IBpk peak current value (battery current), Ilim allowable input current value, T0 control cycle (Li deposition suppression control), VB battery voltage, WIN0 base value (WIN), frp Le frequency.

Claims (1)

A power storage device comprising a lithium ion secondary battery;
An electric motor having an output shaft that forms a power transmission path with the wheels;
A control device for managing charge and discharge of the power storage device,
The control device includes:
A setting means for setting a charging current upper limit value for limiting an input current to the power storage device so that a negative electrode potential of the lithium ion secondary battery does not decrease to a lithium reference potential for each predetermined control cycle;
A first limiting unit that operates every predetermined control period and limits input power to the power storage device when the input current exceeds the charging current upper limit;
In each of the control cycles, detection means for detecting that the input current exceeds the charging current upper limit value instantaneously within the control cycle;
When the input power limitation by the first limiting means is not executed and the detection means detects that the input current exceeds the charging current upper limit value instantaneously, the input current And a second restricting means for restricting the input power when the frequency of the ripple current superimposed on is lower than a predetermined frequency.

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