JP5797004B2 - Battery remaining amount estimation device for electric vehicle - Google Patents

Description

  The present invention relates to an apparatus for estimating the remaining battery level of an electric vehicle, and more particularly to the remaining battery level of an electric vehicle capable of calculating the remaining battery level based on the voltage and current supplied from the battery to a running motor of the electric vehicle. The present invention relates to an estimation device.

  A motor drive circuit for supplying a PWM-modulated drive voltage from the battery to the vehicle driving motor, a first duty ratio map in which a first duty ratio is set in accordance with the grip operation opening, and the vehicle speed from the set value When the vehicle speed is low, the value tends to decrease as the temperature of the motor drive circuit rises.The lower the vehicle speed, the smaller the value at each temperature, and the motor drive circuit temperature becomes the limit value. A second duty ratio map in which a second duty ratio that is zero regardless of the detected vehicle speed is set with respect to the temperature of the motor drive circuit and the detected vehicle speed. Of the second duty ratio, the mode including the smaller information is generated as a motor drive signal. Control device is described in Patent Document 1.

JP 2007-49785 A

  In general, an electric vehicle is provided with a battery remaining amount display portion. When obtaining the remaining amount of battery, first, the value of the charging current supplied at the time of charging is integrated to obtain the full charge amount. Thereafter, a discharge current value discharged from the battery when the vehicle is traveling and when the vehicle is stopped is subtracted from the full charge amount. However, such a battery remaining amount calculation means has to use a relatively expensive current sensor and storage memory, which may greatly affect the price reduction of an electric vehicle, so that improvement is a problem. .

  An object of the present invention is to provide an apparatus for estimating the remaining battery level of an electric vehicle that can calculate the remaining battery level based on current and voltage without using a current sensor.

  In order to achieve the above object, the present invention provides a battery (4), a motor (18) that is supplied with electric power from the battery (4) and generates a driving force of the electric vehicle, and an accelerator grip provided in the electric vehicle. A grip opening sensor (23) for detecting the operation opening (Th) of the motor, and a voltage value supplied to the motor (18) in accordance with the operation opening (Th) is a drive duty ratio of the motor drive circuit (8). And a remaining capacity estimating means (6) for calculating an estimated remaining capacity of the battery (4) using the output voltage and output current of the battery (4) as parameters. In the battery remaining amount estimating device, the remaining amount estimating means (6) passes the motor (18) at a voltage value determined by a duty ratio set in the duty map (48). A discharge current map (49) in which the current value is set in advance corresponding to the duty ratio, and a remaining capacity map (51) in which the remaining capacity of the battery (4) is set in advance based on the current value and the voltage value And using the remaining capacity map (51) from the current value (Imap) calculated by the discharge current map (49) and the actually measured voltage value (Vbatt) supplied to the motor (18). There is a first feature in that it is configured to calculate the remaining capacity in (4).

  In the present invention, when the battery (4) is discharged at a preset current value, a discharge power amount when the discharge voltage is a preset discharge end voltage is preset as a full charge amount, and the battery (4 ) To the motor (18) and the estimated remaining battery capacity based on the current value calculated by the discharge current map (49) at that time is set in the remaining capacity map (51). There is a second feature.

  Further, the present invention has a third feature in that the full charge amount is set based on an average consumption current of the electric vehicle and a discharge end voltage corresponding to the average consumption current.

  Further, the present invention has a fourth feature in that the remaining capacity map is created by linearly approximating a current value that is a parameter of the remaining capacity map.

  The present invention further includes a battery remaining amount display device (7) for displaying the remaining battery level based on the calculated remaining capacity, and immediately after turning on the power, the open circuit voltage is regarded as the remaining battery capacity and the remaining battery level is determined. There is a fifth feature in that the remaining battery level is displayed by the display device (7).

  Further, the present invention has a sixth feature in that the display based on the open circuit voltage is maintained for a predetermined time.

  Further, the present invention has a seventh feature in that the voltage value and the current value input to the remaining capacity map are average values in a predetermined sampling period.

  Further, according to the present invention, when the display value on the battery remaining amount display device (7) has decreased by more than the planned maximum change width from the latest calculated remaining capacity, the current display value is gradually changed to the latest calculated value. There is an eighth feature in that it is configured to be lowered to a minimum.

  Further, according to the present invention, when the motor (18) is stopped, the open circuit voltage is measured every predetermined time, and the remaining battery capacity display device (7) replaces the open circuit voltage with the remaining battery capacity. A ninth feature is that the display is configured.

  According to the present invention having the first feature, the remaining battery level is estimated by detecting only the voltage value without using a current sensor by preparing a discharge current map and a remaining capacity map in advance. Therefore, an electric vehicle with reduced costs can be provided.

  According to the present invention having the second feature, the reference full charge amount determined based on the discharge end voltage, that is, the voltage at which the remaining capacity is zero, the current flowing through the motor by the voltage, and the actual voltage The remaining battery capacity can be obtained without using a current sensor, based on the difference between the value and the power estimated from the current value obtained from the map search.

  According to the third feature, since the remaining battery capacity is calculated based on the full charge amount determined by the discharge end voltage corresponding to the average current consumption, the estimation accuracy is improved. According to the fourth feature, the map is simplified.

  According to the fifth and sixth features, the remaining amount can be displayed even during a period when the characteristics are unstable immediately after the power is turned on. According to the seventh feature, the estimation accuracy of the remaining battery capacity is improved.

  According to the eighth feature, since sudden display fluctuation can be avoided, the user does not feel uncomfortable. According to the ninth feature, it is possible to make the user visually recognize the remaining battery level that varies depending on the general electrical load even when the motor is stopped.

It is a left view of the electric vehicle carrying the battery residual amount estimation apparatus which concerns on one Embodiment of this invention. It is a figure which shows the specific circuit example of the principal part control system of an electric vehicle. It is a block diagram which shows the principal part function of a battery remaining charge estimation part. It is a figure which shows a response | compatibility with a duty map and a discharge current map. It is a figure which shows the constant current discharge characteristic from the full charge state of a battery. It is a figure which shows the relationship between the remaining capacity based on a constant current discharge characteristic, a voltage, and an electric current value. It is a flowchart of a battery remaining charge calculation process. It is a figure which shows the example of an instruction | indication mode of the pointer | guide provided in a battery residual amount display apparatus.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a left side view of an electric vehicle equipped with a battery remaining amount estimating apparatus according to an embodiment of the present invention. The electric vehicle 1 is a scooter type motorcycle having a low floor, and each component is attached to the body frame 3 directly or indirectly through another member. The vehicle body frame 3 includes a head pipe 31, a front frame portion 32 having a front end joined to the head pipe 31 and a rear end extending downward, and a branch from the front frame portion 32 to the left and right in the vehicle body width direction. A pair of main frame portions 33 extending to the rear and a rear frame portion 36 extending from the main frame portion 33 rearwardly on the vehicle body.

  A front fork 2 that supports the front wheel WF is supported by the head pipe 31 so as to be steerable. A steering handle 46 is connected to the upper portion of the steering shaft 41 that extends upward from the front fork 2 and is supported by the head pipe 31. The steering handle 46 is provided with a grip opening sensor 23 that detects a turning angle of an accelerator grip (not shown) provided on the right side of the vehicle body, that is, a grip opening. A headlamp 25 and a front carrier 26 positioned above the headlamp 25 are supported on a front end portion of a bracket 37 coupled to the front portion of the head pipe 31.

  A bracket 34 extending toward the rear of the vehicle body is joined to an intermediate region between the main frame portion 33 and the rear frame portion 36 of the vehicle body frame 3. The bracket 34 is provided with a pivot shaft 35 extending in the vehicle body width direction. A swing arm 17 including a motor 18 as a vehicle drive source is supported on the pivot shaft 35 so as to be swingable up and down. The output of the motor 18 is transmitted to the rear wheel axle 19, and the rear wheel WR supported by the rear wheel axle 19 is driven. The housing including the rear wheel axle 19 and the rear frame portion 36 are connected by the rear suspension 20. The bracket 34 pivotally supports the side stand 24 that supports the vehicle body while the vehicle is stopped. A side stand switch 28 is provided for outputting a detection signal when the side stand 24 is stored at a predetermined position.

  A battery 4 is mounted on the main frame portion 33, and an upper portion of the battery 4 is covered with a cover 40. An air introduction pipe 38 is connected to the front part of the battery 4, and an intake fan 39 is provided to the rear part of the main battery 4. Air is introduced into the battery 4 from the air introduction pipe 38 by the intake fan 39, and the air is discharged to the rear of the vehicle body after cooling the battery 4. Air may be introduced into the air introduction pipe 38 through an air cleaner (not shown).

  A socket 44 is provided on the rear frame portion 36 to which a plug 43 of a charging cable 42 extending from a charger (not shown) for charging the battery 4 can be coupled. The rear frame portion 36 is further provided with a rear carrier 29 and a tail lamp 27. A luggage compartment 50 is provided between the pair of left and right rear frame portions 36. The swing arm 17 is provided with a control device 45. A driver seat 21 that also serves as a lid of the luggage compartment 50 is provided on the luggage compartment 50, and the driver seat 21 has a seat switch 22 that operates when the driver is seated and outputs a seating signal. Provided.

  FIG. 2 is a diagram illustrating a specific circuit example of a main part control system for an electric vehicle. In FIG. 2, the control system includes a battery 4 and a control device 5. The battery 4 is configured as a battery module in which a plurality of batteries 4 are connected in series so as to obtain a desired high voltage. The control device 5 includes a remaining amount estimation unit 6 of the battery 4, an inverter 8 composed of FETs Q <b> 1 to Q <b> 6, and a motor drive unit 9 that drives the inverter 8. The control device 5 is connected to a battery remaining amount display device 7 for displaying the battery remaining amount calculated by the remaining amount estimating unit 6. That is, the control device 5 includes a microcomputer having functions of a remaining amount estimating unit 6 and a motor driving unit 9.

  The three-phase output of the inverter 8 is connected to the three-phase winding of the motor 18. The motor 18 is provided with an angle sensor 10 for detecting the rotor position. The motor drive unit 9 inputs a PWM signal to the FETs Q <b> 1 to Q <b> 6 according to the rotor position detected by the angle sensor 10. The duty ratio of the PWM signal is determined according to the grip opening detected by the grip opening sensor 23 and the motor rotation speed detected based on the output of the angle sensor 10, and the voltage supplied to the motor 18 is controlled. .

  The control device 5 includes a DC-DC converter 11 for stepping down and supplying a battery voltage to a meter device including a general electric load 55 such as a headlamp 25 and a taillight 27 and a remaining battery level display device 7. . The motor 18 is provided with a rotation speed sensor 13 for detecting the rotation speed Nm of the motor 18.

  The plus line 47 of the battery 4 is connected to the input side of the inverter 8 and the input side of the DC-DC converter 11 via an FET (hereinafter referred to as “contactor”) 12 functioning as a contactor. Input capacitors C 1 and C 2 are provided on the input side of the inverter 8. The plus line 47 is connected to one end of the main switch 15 via a resistor R1 and a Zener diode ZD provided in the control device 5, and the other end of the main switch 15 is connected to the control device 5. As a result, the main switch 15 can function as a start switch for turning on the initial power in the control device 5.

  The control system of FIG. 2 operates as follows. First, the plug 43 of the charger 16 separately provided outside the vehicle is connected to the socket 44 during charging. Then, the connection portion between the charging state detection line 14 and the control device 5 changes to a potential indicating the charging state, and accordingly, even if the main switch 15 is turned on, the control device 5 recognizes that it is in the charging state. Therefore, no control command is given to the motor drive unit 9.

  When the charging is completed and the plug 43 is removed from the socket 44, the charging state detection line 14 is opened. Therefore, when the main switch 15 is turned on, the control device 5 confirms that the charger 16 is not connected. This makes it possible to give a control command to the motor drive unit 9. When the main switch 15 as the start switch is turned on, there is no failure of the contactor 12, the voltage of the connected battery 4 is within a specified value, the battery charger 16 is not connected, and the battery The contactor 12 is turned on under the condition that the remaining capacity determined from the open circuit voltage is not zero, and a voltage is applied to the inverter 8 and the DC-DC converter 11. When the grip opening sensor 23 detects that the grip opening is equal to or greater than a predetermined drive start opening value, the duty is increased in accordance with the opening and the motor rotational speed calculated from the output of the angle sensor 10. Thus, the FETs Q1 to Q6 of the inverter 8 are PWM-controlled. The motor 18 is supplied with the output voltage of the inverter 8 determined by the duty ratio of the FETs Q1 to Q6 and rotates.

  FIG. 3 is a block diagram showing main functions of the battery remaining amount estimating unit 6. In FIG. 3, a duty map 48 is a map for searching for the drive duty ratio of the inverter 8, that is, the command value Vmap of the voltage input from the inverter 8 to the motor 18, using the grip opening degree Th and the motor rotation speed Nm as parameters. Yes, the map is set such that the duty ratio increases as the grip opening degree Th increases and the motor rotation speed Nm increases. This map is preset based on actual measurement values.

  The discharge current map 49 is a map for searching for a current value Imap supplied to the motor 18 using the grip opening degree Th and the motor rotation speed Nm as parameters. The current value Imap set in the discharge current map 49 is a current value supplied from the inverter 8 to the motor 18 when the inverter 8 is driven with the duty ratio (voltage value Vmap) set in the duty map 48, and is calculated in advance. It is what I asked for.

  The duty ratio (voltage instruction value) Vmap searched in the duty map 48 is input to the motor drive unit 9, and the motor drive unit 9 drives the FETs Q1 to Q6 of the inverter 8 with the instructed duty ratio.

  The remaining capacity map 51 is a map for obtaining the remaining battery capacity (ampere · hour “Ah”) using the voltage value and the current value as parameters, and is provided in the remaining capacity estimating section 6. Details of the remaining capacity map 51 will be described later. When an input voltage value (actual value) Vbatt to the inverter 8 and a current value Imap obtained based on the discharge current map 49 are input to the remaining capacity map 51 in the remaining amount estimation device 6, these inputs are input. The remaining capacity (Ah) of the battery 4 is output based on the values (Vbatt and Imap). The obtained remaining capacity (Ah) is input to the battery remaining amount display device 7.

  FIG. 4 is a diagram showing the correspondence between the duty nap 48 and the discharge current map 49. As shown in FIG. 4, the duty map 48 and the discharge current map 49 both have the duty ratio Th and the motor rotation speed Nm as parameters, and the motor 18 is driven when the inverter 8 is driven with the duty ratio and the duty ratio. Search for the flowing current. Therefore, the duty map 48 and the discharge current map 49 are correlated, and as shown in FIG. 4, the duty ratio searched in the duty map 48 by the grip opening degree Th and the motor rotational speed Nm is the same grip opening degree Th. And the current value searched in the discharge current map 49 by the motor rotation speed Nm.

  FIG. 5 is a diagram showing a constant current discharge characteristic from the fully charged state of the battery 4 (a single battery, not a module). In FIG. 5, a reference point indicating the fully charged state of the battery 4 is set in advance. The reference point is the amount of electric power (for example, 20 Ah) when the closed circuit voltage CCV becomes a predetermined voltage (for example, 10.5 V) when the average discharge current is a predetermined value (for example, 10 A). The remaining capacity of the battery 4 is calculated based on the electric energy at this reference point.

  Under the set reference point, for example, when discharging at a current value of 20A and the closed circuit voltage CCV at that time is 11.0V, the characteristic line of 20A constant current discharge in FIG. The capacity (Ah) at the intersecting position is read on the horizontal axis. According to FIG. 5, the capacity of 16 Ah can be read. Here, since the reference point indicating full charge is 20 Ah, the value obtained by subtracting 16 Ah from 20 Ah, that is, 4 Ah is the remaining capacity of the battery 4.

  In this way, the remaining capacity is calculated from each discharge current and the closed circuit voltage with the total capacity based on the 10A discharge characteristic as a reference point, and the remaining value using the current value and voltage value as parameters based on the calculation result. A capacity map 51 is created. Note that the value of the discharge end voltage is determined in advance by an experiment, and is determined based on an average value (average current value) of sample data collected during a plurality of test runs. For example, in the running test of the electric vehicle, the discharge end voltage is determined with reference to the case where the average running speed from the start to the stop is 20 km / hour and the average supply current is 10 A.

  FIG. 6 is a diagram showing the relationship between the remaining capacity (Ah), voltage V, and current value I based on the constant current discharge characteristics shown in FIG. FIG. 6 shows the relationship among voltage, current, and remaining capacity as a battery module in which a plurality of batteries are connected in series. Based on this relationship, it is possible to create a remaining capacity map 51 that searches for the remaining capacity (Ah) using voltage and current as inputs. In creating the actual remaining amount map 51, it is convenient to use a value approximated to a linear function instead of a quadratic function state as shown in FIG. . That is, the current value line shown in FIG. 6 is created by correcting the current value to a square root and approximating it to a straight line.

  FIG. 7 is a flowchart of remaining capacity calculation processing. In FIG. 7, in step S <b> 1, as a startup process, the battery voltage (that is, the open circuit voltage) OCV and the temperature of the battery 4 in the no-load state after the main switch 15 is turned on and before the motor 18 is driven. The map is searched by the remaining capacity for open circuit voltage to obtain the remaining battery level set in n stages.

  In step S2, the remaining battery level display device 7 is driven in accordance with the remaining battery level determined in step S1 to display the remaining level. By the process of obtaining the remaining capacity level from the open circuit voltage OCV, it is possible to appropriately cope with an initial remaining level display delay event due to the fact that the characteristics of the battery 4 are not determined until a certain amount of time has elapsed after the start of energization. It should be noted that the display in step S2 is preferably maintained after the main switch 15 is turned on until a time that the characteristic of the battery 4 is estimated to be settled is determined in advance.

  In step S3, it is determined whether the remaining battery level is zero. If the remaining battery level is zero, the process proceeds to step S20 to stop the motor drive. If the remaining battery level is not zero, the process proceeds to step S4 to determine whether or not the motor 18 is being driven. If the motor 18 is being driven, the process proceeds to step S5, the discharge current map 49 is searched, and the discharge current Imap is detected. In step S6, an average value of the discharge current Imap is calculated, and the discharge current Imap obtained during a predetermined time (for example, 5 seconds) is averaged. In step S7, an input voltage (discharge voltage) Vbatt to the inverter 8 is detected. In step S9, similarly to the discharge current Imap, the input voltage (discharge voltage) Vbatt to the inverter 8 detected during a predetermined time is averaged.

  In step S9, it is determined whether or not the battery voltage Vbatt is less than the map lower limit value. If it is determined in step S9 that the battery voltage Vbatt is not less than the map lower limit value, the process proceeds to step S10, where the actually measured battery voltage Vbatt and the map-searched discharge current Imap are input to the remaining capacity map 51 and the remaining battery capacity (Ah ) Is calculated.

  In step S11, the average value of the remaining battery capacity (Ah) calculated in step S10 is calculated. In step S12, the battery remaining capacity calculated last time, that is, the difference (change width) between the currently displayed battery remaining capacity (current capacity value) and the latest battery remaining capacity is calculated. In step S13, it is determined whether or not the change width calculated in step S12 is larger than a predetermined maximum allowable change width. When the change width of the calculated value is smaller than the predetermined maximum allowable change width, the process proceeds to step S14, and the remaining battery capacity calculated this time is reflected to drive the remaining battery capacity display device 7 from the remaining capacity / display voltage conversion table. Search for voltage. In step S15, the battery remaining amount display device 7 is driven by the searched drive voltage (for example, a pointer is driven). The driving of the battery remaining amount display device 7 will be further described later with reference to FIG.

  When the change width of the calculated value of the remaining battery capacity is larger than the predetermined maximum width, the process proceeds from step S13 to step S16, and the maximum change width is subtracted from the current remaining capacity (Ah). After subtracting the maximum amount of change from the current remaining capacity (Ah) in step S16, the process proceeds to step S14 to reflect the remaining capacity (Ah) after subtraction from the remaining capacity / battery remaining capacity conversion table. Search for. In this way, when the range of change is large, the alternative remaining capacity is displayed instead of the calculated remaining battery capacity, and the display value is gradually changed (for example, by 5%) to give the user a sense of discomfort. There is no effect.

  In step S9, if it is determined that the battery voltage Vbatt is less than the map lower limit value, the remaining battery capacity is low, and accordingly, for example, processing such as output limitation is performed.

  In step S17, the discharge end voltage that is the lower limit voltage value corresponding to the discharge current value Imap obtained by searching the discharge current map 49 is searched using, for example, a search table (discharge end voltage table). In step S18, it is determined whether or not the inverter output voltage Vbatt is equal to or higher than the discharge end voltage value. If step S18 is negative, the process proceeds to step S16. On the other hand, if step S18 is affirmative, the process proceeds to step S19 to set the remaining capacity (Ah) to zero, and the process proceeds to step S20 to stop the motor drive.

  Until step S4 is negative, that is, until the motor 18 is driven, the process proceeds to step S21 to determine whether or not a predetermined time (for example, 10 minutes) has elapsed. Until the predetermined time elapses, the process returns to step S3, but when the predetermined time elapses, the process proceeds to step S22. To do. By these steps S21 and S22, even when the motor 18 is stopped and the vehicle is stopped, the remaining capacity of the battery 4 can be periodically displayed and recognized by the user. Depending on the lighting of the DC-DC converter 11 and the lighting device, the remaining amount of the battery 4 changes even when the vehicle is stopped, so it is meaningful to display the remaining capacity.

  Next, the display of the battery remaining amount display device 7 will be described. FIG. 8 is a diagram illustrating an example of an indication mode of a pointer provided in the battery remaining amount display device 7. In FIG. 8, on the display surface of the battery remaining amount display device 7, a scale 7a, a red zone 7b in which the remaining capacity is almost zero, and a full zone 7c indicating a fully charged state are shown. The pointer 7d is driven between the red zone 7b and the full zone battery 7c on the scale 7a.

  Since it is an estimated value near the upper and lower limits of the remaining capacity of the battery 4, it is assumed that the calculated value of the remaining capacity deviates from the true value. Therefore, in order to avoid a large display error in the upper and lower limit areas of the remaining battery capacity, for example, in a range of less than 2 Ah or more than 16 Ah in a 20 Ah battery, the following points are taken into consideration for the display in the remaining battery capacity display device 7.

  The calculated value of the remaining amount when the remaining capacity of the battery 4 is large is shifted by about 2 to 3 Ah from the actual value, and from the viewpoint of grasping the deterioration standard of the battery 4, in the high remaining capacity region of 16 Ah or more in the 20 Ah battery Until the calculated remaining capacity is reduced to 80% of full charge (equivalent to 16 Ah), the pointer 7d of the battery remaining amount display device 7 is displayed at the position of the full zone 7c of the scale 7a (see FIG. 8A). ).

  On the other hand, in order to allow a deviation of about 1 Ah from the actual value in the vicinity of the remaining amount of zero, the remaining capacity 2 Ah is set as the lower display limit in the 20 Ah battery. Therefore, as shown in FIG. 8B, when the calculated remaining capacity is in the range of 2 Ah to 4 Ah in the 20 Ah battery, the pointer 7 d is driven to be positioned in the red zone 7 b. Further, when the calculated remaining capacity becomes 2 Ah or less in the 20 Ah battery, the pointer 7 d is driven so as to be positioned at the lowest limit of the displayable range (the end of the red zone 7 b) (see FIG. 8C).

  As described above, according to the present embodiment, the remaining capacity of the battery 4 can be estimated by calculation and displayed on the battery remaining amount display device 7 without using an ammeter. In addition, this invention is not limited to the above-mentioned embodiment, It can deform | transform by applying a well-known technique within the range described in the claim.

  DESCRIPTION OF SYMBOLS 4 ... Battery, 6 ... Remaining amount estimation part, 7 ... Battery remaining amount display apparatus, 8 ... Inverter, 9 ... Motor drive part, 10 ... Angle sensor, 11 ... DC-DC converter, 12 ... Contactor, 13 ... Speed sensor 15 ... main switch 16 ... charger 18 ... motor 22 ... seat switch 23 ... grip opening sensor 48 ... duty map 49 ... discharge current map 51 ... remaining capacity map

Claims (5)

A battery (4), a motor (18) that is supplied with electric power from the battery (4) to generate driving force of the electric vehicle, and a grip opening that detects an operation opening (Th) of an accelerator grip provided in the electric vehicle. A duty map (48) in which a voltage value supplied to the motor (18) in accordance with the degree of operation opening (Th) is preset as a drive duty ratio of the motor drive circuit (8); In a battery remaining amount estimating device for an electric vehicle, comprising: remaining amount estimating means (6) for calculating an estimated remaining capacity of the battery (4) using the output voltage and output current of the battery (4) as parameters,
The remaining amount estimating means (6)
A discharge current map (49) in which a current value when the motor (18) is energized with a voltage value determined by the duty ratio set in the duty map (48) is set in advance corresponding to the duty ratio;
A remaining capacity map (51) in which the remaining capacity of the battery (4) is set in advance based on the current value and the voltage value;
From the current value (Imap) calculated by the discharge current map (49) and the actually measured voltage value (Vbatt) supplied to the motor (18), the remaining capacity map (51) is used to determine the battery (4). Configured to calculate the remaining capacity,
A battery remaining amount display device (7) for displaying a battery remaining amount based on the calculated remaining capacity;
Immediately after turning on the power, the open circuit voltage is regarded as the remaining battery capacity, and the remaining battery capacity is displayed by the remaining battery capacity display device (7).
A configuration in which the current display value is gradually reduced to the latest calculated value when the latest calculated remaining capacity is reduced by more than the planned maximum change width from the display value on the battery remaining amount display device (7). Has been
The battery remaining amount display device (7) is a method of displaying the remaining amount of the battery with a swinging-type pointer (7d), and the pointer (7d) is displayed on a full zone until it is reduced to 80% of the full charge. On the other hand, when the full charge is 10% or less, the pointer (7d) is driven to the lowest position of the displayable range ,
When the battery (4) is discharged at a preset current value, the discharge power amount when the discharge voltage is a preset discharge end voltage is preset as a full charge amount,
The estimated battery remaining capacity based on the voltage input from the battery (4) to the motor (18) and the current value calculated by the discharge current map (49) at that time is set in the remaining capacity map (51). And
The full charge amount is set based on the average consumption current and discharge end voltage of the electric vehicle,
When the open circuit voltage as the remaining battery capacity immediately after the power is turned on is not zero and the motor (18) is driven, the current value is obtained by the discharge current map (49),
A remaining battery capacity estimation device for an electric vehicle , wherein the remaining battery capacity is calculated using the remaining capacity map (51) when the measured voltage value (Vbatt) is not less than a map lower limit value . The remaining battery capacity estimation device according to claim 1 , wherein the remaining capacity map (51) is created by linearly approximating a current value that is a parameter of the remaining capacity map (51). . The apparatus according to claim 1 or 2 , wherein the display based on the open circuit voltage is maintained for a predetermined time.   2. The battery remaining capacity estimating device for an electric vehicle according to claim 1, wherein the voltage value and the current value input to the remaining capacity map are average values in a predetermined sampling period. While the motor (18) is stopped, the open circuit voltage is measured every predetermined time, and the remaining battery capacity is displayed by the remaining battery capacity display device (7) instead of the open circuit voltage. The battery remaining amount estimation device for an electric vehicle according to any one of claims 1 to 4 , wherein the battery remaining amount estimation device is an electric vehicle.