JP6497807B2 - Electric car - Google Patents

Description

  The present invention relates to an electric vehicle having a motor generator and a battery for supplying electric power to the motor generator.

  In recent years, a hybrid vehicle equipped with a motor generator separately from an engine has attracted attention as an environmentally friendly electric vehicle. The motor generator in such a hybrid vehicle generates a vehicle driving force during acceleration, and performs regenerative power generation that converts kinetic energy of the vehicle into electric energy during deceleration such as braking. In hybrid vehicles, energy efficiency is improved by collecting regenerative power from a motor generator by charging a battery.

  Here, if the regenerative power from the motor generator becomes excessive, there may be a problem in component protection such as generation of overvoltage or overcharge of the battery. Therefore, it is necessary to control so that the regenerative power from the motor generator does not become excessive. For this reason, the voltage detection means and the current detection means detect the voltage and current of the battery while the electric vehicle is running, and when the detected voltage exceeds the reserve voltage, or the detected current exceeds the reserve current. When it becomes, the technique which suppresses the regenerative power generation amount of a motor generator is proposed (for example, refer patent document 1).

  Further, nickel hydride secondary batteries are conventionally used for batteries used in this electric vehicle (see, for example, Patent Document 2). In this nickel metal hydride secondary battery, it is known that gas is generated from each power generation element due to the polarization of the power generation element, etc., and the internal pressure rise due to the generated oxygen gas and the oxygen gas between each power generation element There is a risk of capacity degradation due to variations in discharge reserve due to movement.

JP 7-264709 A JP 2008-311015 A

  However, in order to solve the increase in the discharge reserve variation and the increase in internal pressure by the method of Patent Document 1, it is necessary to set the reserve voltage high when adjusting to the short-time large current charging. There is a problem that the battery voltage is low but the high electromotive force cannot be protected. On the other hand, if the reserve voltage is set to be low in accordance with the small current for a long time, the short-time large current that should be allowed is also limited, which causes a problem that the battery cannot be utilized to the maximum extent.

  On the other hand, the amount of oxygen gas generated during charging varies depending on the state of charge of the battery (hereinafter referred to as “SOC” (State of Charge)). That is, if the SOC is high, the amount of oxygen gas generated increases and the amount of electricity that can be charged is small. If the SOC is low, the amount of oxygen gas generated decreases and the amount of electricity that can be charged increases.

  Further, in regenerative power generation by a motor generator that runs at a reduced speed, regenerative torque is generated in the motor generator. This regenerative torque becomes a deceleration force in the travel of the hybrid vehicle and becomes a braking force similarly to the engine brake. Accordingly, the greater the regenerative power of the motor generator, the higher the braking force of the automobile. The smaller the regenerative power of the motor generator, the lower the braking force of the automobile. Therefore, when the regenerative power generation is suppressed, the braking force is reduced, and a sudden reduction in the braking force also has a problem of reducing the drivability of the automobile.

  An object of the present invention is to provide an electric vehicle capable of performing effective use of a battery within a range in which charging is performed in accordance with the SOC and the reserve variation progresses and the internal pressure does not increase.

  The present invention includes a motor generator and a battery that supplies power to the motor generator, and includes motor generator control means that charges the battery with power generated by regenerative power generation of the motor generator at least during deceleration, When the battery current integrated value reaches a predetermined charge inhibition current integrated value, the generator control means is configured to stop charging the battery until the discharge current reaches the predetermined discharge current integrated value. It is an improvement.

  The characteristic point is that a battery SOC detection means for detecting the SOC of the battery is provided, and the motor generator control means is configured to vary the charge inhibition current integrated value in accordance with the SOC.

  In this case, the current integrated value of the battery is preferably a value obtained by subtracting the additional integrated value obtained by increasing the integrated value of the discharge current by a predetermined magnification from the integrated value of the charging current.

  On the other hand, when the battery current integrated value reaches the throttle start current integrated value before the battery current integrated value reaches the predetermined charge inhibition current integrated value, the motor generator control means changes the battery current integrated value from the throttle start current integrated value to the predetermined charge. It can be controlled to gradually reduce the amount of charge to the battery until it reaches the forbidden current integrated value, and the current integrated value when the charge amount becomes zero by making the rate of decrease of the gradually decreased battery charge amount uniform. Is a throttle destination current integrated value, it is preferable to determine the charge inhibition current integrated value before the throttle destination current integrated value. The motor generator control means more preferably varies the throttle start current integrated value and the throttle destination current integrated value together with the charge inhibition current integrated value according to the state of charge of the battery.

  In the electric vehicle of the present invention, since the charge prohibition current integrated value is changed according to the SOC of the battery, if the SOC is high, the charge prohibition current integrated value becomes a small value, and the amount of electricity that can be charged decreases. Thus, it is possible to avoid a situation where the battery is charged beyond the amount of electricity that can be charged.

  On the other hand, if the SOC is low, the charge inhibition current integrated value becomes a large value, and the amount of electricity that can be charged increases, so that the charge amount close to the amount of electricity that can be charged by the battery can be charged, It is possible to measure the optimum use of the battery while suppressing the progression of reserve dispersion and the increase in internal pressure due to the generation of oxygen gas.

  If the amount of charge to the battery is gradually reduced before the battery current integrated value reaches the predetermined charge prohibition current integrated value, the braking force of the automobile will gradually decrease, and charging is prohibited immediately. Compared with the case where it is done, it can prevent that the operativity which a driver | operator feels due to the reduction | decrease of braking force deteriorates.

It is a block block diagram of the electric vehicle of embodiment of this invention. (A) It is a figure which shows the relationship between the charging / discharging electric current by motor vehicle driving | running | working, and an electric current integrated value, and the relationship between (B) electric current integrated value and charge amount. It is a figure which shows the relationship between SOC of the battery, and charging prohibition electric current integrated value. It is a figure which shows the relationship between the temperature of the battery, generation | occurrence | production of gas, and an absorption rate.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram illustrating an example of a configuration of a hybrid vehicle 1 that is an electric vehicle. The hybrid vehicle 1 includes an engine 10 that generates power for running the hybrid vehicle 1, a motor generator 13 connected to the engine 10 via a clutch 12, and a transmission 16 connected to the motor generator 13.

  The engine 10 is an example of an internal combustion engine, and generates power to drive the hybrid vehicle 1 by internally burning gasoline, light oil, CNG (Compressed Natural Gas), LPG (Liquefied Petroleum Gas), or alternative fuel. Configured as follows. In the figure, the engine 10 is a diesel engine using light oil as a fuel, and reference numeral 10a indicates a fuel injection device 10a that injects light oil that is the fuel.

  The clutch 12 is exemplified as one that is mechanically controlled by the clutch booster 22 according to the hydraulic pressure controlled by the clutch actuator 21. A motor generator 13 is connected to the engine 10 via the clutch 12, and the transmission 16 further connected to the motor generator 13 is a semi-automatic one. The clutch 12 is configured to transmit the shaft output from the engine 10 to the wheel 1 c via the transmission 16. That is, the clutch 12 is configured to connect the engine 10 and the transmission 16 to run the hybrid vehicle 1.

  The motor generator 13 is a so-called motor generator that generates power for rotating the shaft by the electric power supplied from the inverter 14 and supplies the shaft output to the transmission 16 to drive the hybrid vehicle 1. Alternatively, the power is generated by the power that rotates the shaft supplied from the transmission 16 due to the traveling of the hybrid vehicle 1 or the power that is directly supplied from the engine 10, and the power is supplied to the inverter 14.

  The hybrid vehicle 1 includes a battery 15, and the inverter 14 converts DC power from the battery 15 into AC power, or converts AC power generated by the motor generator 13 into DC power. When the motor generator 13 generates power, the inverter 14 converts the DC power of the battery 15 into AC power, supplies the motor generator 13 with power, and when the motor generator 13 generates power, the inverter 14 The AC power from the motor generator 13 is configured to be converted into DC power. That is, the inverter 14 serves as a rectifier and a voltage regulator for supplying DC power to the battery 15.

  The battery 15 is a chargeable / dischargeable secondary battery. When the motor generator 13 generates power, the battery 15 supplies power to the motor generator 13 via the inverter 14 or the motor generator 13 generates power. When the motor generator 13 is in operation, it is charged by the electric power generated by the motor generator 13. The hybrid vehicle 1 is also provided with a cooling device (not shown) for cooling the battery 15 because the amount of power generated by the motor generator 13 is large.

  In addition, the hybrid vehicle 1 is provided with a control device 2 that controls the engine 10 and the clutch 12 to run the hybrid vehicle 1. The control device 2 in this embodiment includes an engine ECU 11 that controls the engine 10 in accordance with a driver request torque obtained from the depression amount of the accelerator pedal 3, a hybrid ECU 17 that controls the motor generator 13 via an inverter 14, and a battery ECU 23. And at least.

  Here, the engine ECU 11 that controls the engine 10 and the hybrid ECU 17 that controls the motor generator 13 cause the engine 10 and the motor generator 13 to output torque equal to the driver request torque obtained from the depression amount of the accelerator pedal 3. In that respect, the driving power control means 19 is configured.

  The engine ECU 11, the hybrid ECU 17 and the like are so-called computers configured by a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), a microprocessor (microcomputer), a DSP (Digital Signal Processor), and the like. In addition, an arithmetic unit, a memory, an I / O (Input / Output) port, and the like are provided.

  The engine ECU 11 is connected to a detection output of an accelerator sensor 4 that detects the amount of depression of the accelerator pedal 3, and the control output of the engine ECU 11 is connected to a fuel injection device 10 a of the engine 10. The engine ECU 11 is configured to control the engine 10 such as a fuel injection amount and a valve timing in accordance with a driver request torque required from a depression amount of the accelerator pedal 3.

  The hybrid ECU 17 that constitutes the traveling power control means 19 together with the engine ECU 11 is a computer that operates in cooperation with the engine ECU 11, and is configured to control the motor generator 13 by controlling the inverter 14. When the accelerator pedal 3 is not depressed, the motor generator 13 is driven by the power supplied from the transmission 16 due to the traveling of the hybrid vehicle 1 to generate power, and the electric power obtained by the power generation is The battery 15 is configured to be charged.

  The battery ECU 23 is connected to the battery 15, and the battery 15 is connected to the hybrid ECU 17 via the battery ECU 23. The battery ECU 23 detects the temperature of the battery 15, the current value at the time of charging / discharging, and the SOC thereof, and outputs the SOC to the hybrid ECU 17. The hybrid ECU 17 uses the battery ECU 23 to output the SOC information of the battery 15. Configured to be obtainable. An appropriate SOC range is determined for the battery 15, and the battery ECU 17 manages the SOC of the battery 15 so that the SOC does not deviate from the range.

  The battery ECU 23, the engine ECU 11, and the hybrid ECU 17 are connected to each other by a bus that complies with a standard such as CAN (Control Area Network) together with other control devices (not shown). The program executed by the hybrid ECU 17 is stored in advance in a non-volatile memory inside the hybrid ECU 17 so that the program is installed in advance in the hybrid ECU 17 that is a computer.

  The hybrid ECU 17 acquires the accelerator opening information, the brake operation information, the vehicle speed information, the gear position information acquired from the transmission 16, the engine rotation speed information acquired from the engine ECU 11, and the acquired accelerator opening for the hybrid traveling. The inverter 14 is controlled based on the degree information and other information, and a control instruction for the engine 10 is given to the engine ECU 11. Accordingly, the hybrid vehicle 1 is configured to run or stop.

  Further, based on the accelerator opening information and the brake operation information described above, the hybrid ECU 17 causes the motor generator 13 to generate electric power using the kinetic energy at the time of deceleration when the hybrid vehicle 1 is in the deceleration state, and the electric energy is stored in the battery. 15 is configured to take a decelerating run that is charged and recovered. That is, in this decelerating running, the motor generator 13 operates as a generator, generates electric power by rotating the shaft supplied from the transmission 16, supplies electric power to the inverter 14, and charges the battery 15. Composed.

  Therefore, the hybrid ECU 17 that charges the battery 15 with the electric power generated by the motor generator 13 and the battery ECU 23 that outputs the state of the battery 15 to the hybrid ECU 17 use the electric power generated by the regenerative power generation of the motor generator 13 as the battery 15. The battery ECU 23 constitutes battery charge state detection means in the present invention in that the SOC of the battery 15 is detected and output to the hybrid ECU 17. is there.

  Here, the motor generator 13 in a state of generating power generates a regenerative torque having a magnitude corresponding to the regenerative power. When the motor generator 13 is generating electric power (regenerating power) in this way, the hybrid ECU 17 connects the rotating shaft of the engine 10 and the rotating shaft of the motor generator 13 via the clutch 12 as necessary. The mechanical connection is disconnected and the engine 10 is stopped or idling.

  The characteristic configuration of the present invention is that the hybrid ECU 17 constituting the motor generator control means 18 is configured such that when the current integrated value of the battery 15 reaches a predetermined charge inhibition current integrated value, the discharge current is a predetermined discharge current integrated value. The charging of the battery 15 is stopped until reaching the value, and the charge inhibition current integrated value is varied according to the SOC of the battery 15 provided from the battery ECU 23. That is, the motor generator control means 18 includes charge prohibition current integrated value fluctuation determining means for changing the charge prohibition current integrated value in accordance with the SOC of the battery 15.

  Here, FIG. 2 shows an example of the relationship between the charge / discharge current and the integrated current value in a certain SOC. In FIG. 2, the horizontal axis indicates the time when the current integrated value is reset and starts from zero until the current integrated value reaches the charge inhibition current integrated value B, and the charge / discharge current and the current integrated value are expressed on the vertical axis. FIG. In this graph, although the battery 15 is charged for most of the time, the time during which the automobile 1 is accelerated and the battery 15 is discharged for a short time is included. Here, the short-time discharge means discharge in which the integrated value is less than a predetermined discharge current integrated value to be reset.

  As shown in FIG. 2, when the motor vehicle decelerates and the motor generator 13 generates power and the battery 15 charges the electric power, the current integrated value of the battery 15 approaches the charge inhibition current integrated value B, and conversely, the battery 15 Is discharged, the current integrated value of the battery 15 is moved away from the charge inhibition current integrated value B. That is, the integrated current value of the battery 15 is obtained by subtracting the integrated value of the charging current from the integrated value of the discharge current.

  This prevents the current integrated value from being reset to zero due to a short-time discharge, and prevents the current integrated value from being reset due to a short-time discharge during a long continuous charge. Thus, continuous charging exceeding a predetermined time is prevented.

  However, if a short-time discharge is generated during continuous charging, an additional integrated value obtained by increasing the current integrated value of the short-time discharge by a predetermined magnification is set to a value obtained by subtracting from the integrated value of the charging current. This is determined from the viewpoint of preventing an increase in discharge reserve variation and an increase in internal pressure, and the generation of oxygen gas from each power generation element in the battery 15 can be suppressed even with a relatively small discharge with respect to the charge amount. It is.

  That is, the increase in the discharge reserve variation and the increase in the internal pressure in the battery 15 are caused by the generation of oxygen gas from each power generation element. This generation of oxygen gas causes polarization (voltage rises) in the positive electrode of the power generation element by charging, and oxygen gas is generated from the positive electrode due to the polarization. Even after the charge is completed, oxygen gas continues to be generated in the positive electrode while consuming the polarization (while the voltage decreases), so if the charge is restarted before the polarization becomes sufficiently small, a large amount of oxygen gas is generated immediately. Will do. For this reason, in the present invention, when the current integrated value reaches a predetermined charge prohibited current integrated value, charging is prohibited for a certain period of time.

  However, since the polarization at the positive electrode is eliminated with a relatively small discharge with respect to the charge amount, oxygen gas can be used even if the integrated value on the discharge side is small before the current integrated value reaches the predetermined charge prohibited current integrated value. Occurrence can be suppressed. Further, if integration on the discharge side without magnification is performed, there is a possibility that charging cannot be performed even though polarization has already been eliminated. For this reason, a value obtained by subtracting the additional integrated value obtained by increasing the current integrated value of the short-time discharge by a predetermined magnification from the integrated value of the charging current is used as the integrated current value.

  Then, as shown in FIG. 2B, the hybrid ECU 17 that is the motor generator control means is a throttle start current integrated value before the integrated value of the charging current to the battery 15 reaches a predetermined charge prohibiting current integrated value B. When A is reached, control is performed so that the amount of charge to the battery 15 is gradually decreased until the current integrated value of the battery 15 reaches the predetermined charge inhibition current integrated value B from the throttle start current integrated value A.

  Here, in the regenerative power generation by the motor generator 13 traveling at a reduced speed, a regenerative torque is generated in the motor generator 13 and becomes a braking force in the travel of the hybrid vehicle 1. Therefore, a rapid decrease in the amount of charge to the battery 15 causes a rapid decrease in braking force, which may reduce the drivability of the automobile. Therefore, before the charging of the battery 15 is prohibited, the amount of charge to the battery 15 is gradually reduced and the braking force is gradually reduced, so that the drivability of the automobile due to the sudden decrease in the braking force is achieved. It is intended to prevent a decrease.

  Further, the rate of decrease of the charge amount of the battery 15 that is gradually reduced is preferably uniform in order not to reduce the drivability of the automobile, but as shown in FIG. If the current integrated value in the case of zero is the throttle destination current integrated value C, it is preferable to determine the charge inhibition current integrated value B before the throttle destination current integrated value C.

  That is, in order not to reduce drivability, when the current integrated value of the battery 15 reaches the throttle start current integrated value A, the charge amount to the battery 15 is gradually reduced. However, if the throttle destination current integrated value C at which the gradually reduced charging amount becomes zero is set as the charge inhibition current integrated value B, the current integrated value does not decrease in the vicinity of the throttle destination current integrated value C, and the current integrated value This is because there is a risk that charging will not be prohibited or the prohibition will not be released without reaching the charging prohibited current integrated value B.

  In the present invention, the hybrid ECU 17 constituting the motor generator control means 18 varies the throttle start current integrated value A and the throttle destination current integrated value C in accordance with the SOC of the battery 15, and thereby the charge inhibition current integrated value. B is also varied according to the SOC of the battery 15.

  That is, if the SOC of the battery 15 is high, the amount of electricity that can be charged to the battery 15 is small, and if the SOC is low, the amount of electricity that can be charged to the battery 15 is large. For this reason, as shown in FIG. 3, basically, if SOC is high, charge inhibition current integrated value B is lowered, and if SOC is low, charge inhibition current integrated value B is set to a high value. In this way, by changing the charging prohibition current integrated value B according to the SOC of the battery 15, the amount of electricity that can be charged is reduced and the battery 15 exceeds the allowable range when the SOC of the battery 15 is high. Avoid situations where recharging occurs. Conversely, if the SOC of the battery 15 is low, the amount of electricity that can be charged to the battery 15 is increased, and the amount of electricity that is charged to the battery 15 is increased. As a result, the battery 15 can be effectively utilized while preventing an increase in variation in discharge reserve and an increase in internal pressure in the battery 15.

  Here, the charge inhibition current integrated value B is individually set by the battery 15. FIG. 3 is a diagram showing a graph in which the aperture start current integrated value A, the aperture destination current integrated value C, and the charge inhibition current integrated value B are varied in accordance with the SOC of the battery 15, and both graphs show an increase in SOC. The aperture start current integration value A, the aperture destination current integration value C, and the charge inhibition current integration value B are decreased. FIG. 3 (a) shows that the charge inhibition current integrated value B or the like does not change when the SOC is low, and the charge prohibition current integrated value B or the like increases as the SOC increases when the SOC becomes a high range beyond the low range. The case where it fluctuates so as to decrease gradually is shown. On the other hand, as shown in FIG. 3 (b), the electric prohibition current integrated value B or the like may be changed stepwise according to the SOC of the battery 15.

  Further, a graph as shown in FIG. 3 may be created for each temperature of the battery 15, and the charge inhibition current integrated value B may be varied depending on the temperature of the battery 15. This is because, as shown in FIG. 4, the battery 15 causes a difference in the amount of oxygen gas to be generated and the amount of oxygen gas to be absorbed due to the difference in temperature.

  That is, when the battery 15 is in an appropriate temperature range within the range between the predetermined lower limit appropriate temperature and the predetermined upper limit appropriate temperature in FIG. 4, the amount of oxygen gas generated is small and the oxygen gas absorption is moderate. . For this reason, even if the charge inhibition current integrated value B is set to be relatively high, the increase in the internal pressure of the battery 15 and the expansion of the reserve variation are suppressed.

  However, in the battery 15 at a low temperature that has not reached the predetermined lower limit appropriate temperature in FIG. 4, although the amount of oxygen gas generated is small, the recombination reaction (absorption) of oxygen gas generated with the negative electrode hydrogen is slow. Therefore, unless the charge inhibition current integrated value B is set to be relatively low, there is a risk that the internal pressure increase and the reserve variation of the battery 15 will increase.

  Further, in the battery 15 at a high temperature exceeding the predetermined upper limit appropriate temperature in FIG. 4, although the oxygen gas is absorbed moderately, the amount of generated oxygen gas itself becomes large. If it is not set relatively low, the internal pressure of the battery 15 may increase and the reserve variation may increase.

  Therefore, if the charging prohibition current integrated value B is changed also depending on the temperature of the battery 15, charging according to the temperature of the battery 15 becomes possible, effectively preventing an increase in discharge reserve variation and an increase in internal pressure in the battery 15, Further effective utilization of the battery 15 can be achieved.

  The graph shown in FIG. 3 is stored in a memory such as the hybrid ECU 17 that constitutes the motor generator control unit 18, and the hybrid ECU 17 compares the SOC input from the battery ECU 23 with respect to this graph, and the corresponding throttle start current integration. The value A, the aperture current integrated value C, and the charge inhibition current integrated value B are determined.

  The hybrid ECU 17 then calculates the integrated current value of the battery 15 based on the determined throttle start current integrated value A, throttle destination current integrated value C, and charge inhibition current integrated value B, as shown in FIG. When the battery reaches the predetermined charge inhibition current integrated value B, the charging of the battery 15 is stopped until the discharge current reaches the predetermined discharge current integrated value. As a result, an excessive generation state of oxygen gas is avoided, and a situation such as capacity deterioration or increase in internal pressure due to expansion of reserve variation is prevented.

  In the embodiment described above, a graph as shown in FIG. 3 is stored in a memory such as the hybrid ECU 17 constituting the motor generator control means 18, and the hybrid ECU 17 displays the SOC input from the battery ECU 23 in this graph. In the above description, the case where the corresponding aperture start current integrated value A, aperture destination current integrated value C, and charge inhibition current integrated value B are determined has been described. However, this control may be performed by the battery ECU 23 constituting the motor generator control means 18, or may be performed by another ECU.

  In the above-described embodiment, the graph as shown in FIG. 3 is stored in a memory such as the hybrid ECU 17 constituting the motor generator control means 18, and the hybrid ECU 17 displays the SOC input from the battery ECU 23 in this graph. In the above description, the case where the corresponding aperture start current integrated value A, aperture destination current integrated value C, and charge inhibition current integrated value B are determined has been described. However, instead of storing the graph as shown in FIG. 3 in the memory, a mathematical expression representing a physical model for obtaining the aperture start current integrated value A, the aperture destination current integrated value C, and the charge inhibition current integrated value B from the SOC is shown. You may make it memorize | store in memory and obtain | require the charging prohibition electric current integrated value B etc. using the numerical formula.

  In the above-described embodiment, the charging of the battery 15 at the time of decelerating driving for decelerating the automobile has been described. However, as long as the battery 15 is charged, the motor generator 13 is driven by the engine 10 to generate power. The battery 15 may be charged by power generation other than during deceleration traveling, such as power generation during downhill traveling and power generation during low-speed traveling.

  In the above-described embodiment, the case where the electric vehicle is the hybrid vehicle 1 including the engine 10 and the motor generator 13 has been described. However, the electric vehicle may be an electric vehicle that does not include an engine as long as it includes the battery 15 and the motor generator control means 18 that charges the battery 15.

  Furthermore, even if the electric vehicle is the hybrid vehicle 1 including the engine 10 and the motor generator 13, in the above-described embodiment, the hybrid vehicle 1 in which the engine 10 is connected to the motor generator 13 via the clutch 12 is used. Illustrated. However, the arrangement of the engine 10 and the motor generator 13 is not limited to this. For example, a hybrid vehicle in which the clutch 12 is not provided between the engine 10 and the motor generator 13 may be used.

DESCRIPTION OF SYMBOLS 10 Engine 13 Motor generator 15 Battery 18 Motor generator control means 23 Battery ECU (battery charge state detection means)
A Aperture start current integrated value B Charging prohibited current integrated value C Restriction destination current integrated value

Claims (5)

A motor (13) and a battery (15) for supplying electric power to the motor generator (13), and at least the electric power generated by regenerative power generation of the motor generator (13) during deceleration of the battery ( 15) equipped with a motor generator control means (18) for charging,
The motor generator control means (18), when the current integrated value of the battery (15) reaches a predetermined charge prohibition current integrated value (B), until the discharge current reaches a predetermined discharge current integrated value, (15) an electric vehicle configured to stop charging,
Battery charge state detection means (23) for detecting the charge state of the battery (15) is provided,
The electric vehicle, wherein the motor generator control means (18) is configured to vary the charge inhibition current integrated value (B) according to a state of charge of the battery (15).   The electric vehicle according to claim 1, wherein the current integrated value of the battery (15) is a value obtained by subtracting an additional integrated value obtained by increasing the integrated value of the discharge current by a predetermined magnification from the integrated value of the charging current.   When the motor generator control means (18) reaches the aperture start current integration value (A) before the current integration value of the battery (15) reaches the predetermined charge inhibition current integration value (B), the battery (15) The control is performed so that the amount of charge to the battery (15) is gradually decreased until the current integrated value of the current reaches the predetermined charging prohibited current integrated value (B) from the throttle start current integrated value (A). 2. The electric vehicle according to 2.   Assuming that the integrated current value when the charging amount of the battery (15) that is gradually reduced is equalized and the charge amount becomes zero is the aperture current integrated value (C), the aperture current integrated value (C The electric vehicle according to claim 3, wherein the charging prohibition current integrated value (B) is determined before this.   The motor generator control means (18), along with the charge inhibition current integrated value (B), the throttle start current integrated value (A) and the throttle destination current integrated value (C) according to the state of charge of the battery (15). The electric vehicle according to claim 4, which is varied.

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