JP5443241B2 - Battery control device for electric vehicle - Google Patents

Description

The present invention relates to a control device for a secondary battery used for a traveling power source of a hybrid vehicle or an electrically assisted bicycle, and in particular, an electric vehicle battery capable of calculating a travelable distance from the remaining capacity of the battery. The present invention relates to a control device.

In a conventional battery control device for an electric vehicle, the remaining travel distance (remaining travel distance) from the current time point is calculated using the remaining capacity and discharge current of the secondary battery.

However, since this method does not consider the influence of the road gradient, the estimated travelable distance is inaccurate.

In addition, when driving on the same road on the forward and return roads, the driver of the electric vehicle is interested in whether or not he / she can return to the starting point with the remaining capacity of the battery. , Did not present at which point you will not be able to return to the starting point.

As described in Patent Document 1, a battery using a remaining battery capacity that has been corrected using a remaining battery capacity of an actual running battery is described in order to determine the remaining traveling distance more accurately. ing.

However, the technique described in Patent Document 1 is merely a more accurate method for determining the remaining battery capacity, and does not take into account any road gradient when determining the remaining travel distance. Is not performed. Whether an electric vehicle, a hybrid vehicle, an electric assist bicycle, or the like can be returned to the power receiving station is a matter of life and death, and it is very important to obtain the remaining travel distance in consideration of road conditions.

Japanese Patent No. 2675874

In the conventional battery control device for an electric vehicle, as shown in FIG. 6, the remaining battery capacity is calculated from the terminal voltage of the secondary battery and the amount of discharged electric power, and further the travelable distance is calculated.

However, in the conventional calculation, when the current electric vehicle is traveling at 40 km / h, and the discharge current is 3 Ah, the remaining travel distance is simply determined as the speed, speed, and discharge current will not change in the future. I'm calculating.

However, since this method does not take into account fluctuations in the discharge current due to the road gradient and the regenerative current value, only an inaccurate distance that can be traveled can be calculated.

The present invention has been made in order to solve the above-described problems. On the premise that the same road is passed on the forward path and the return path, not only the discharge current from the secondary battery and the regenerative current to the battery, but also the gradient of the road. Electric vehicle that can notify the driver at which point it is not possible to return to the starting point during forward traveling by calculating the power consumption required to travel from that point to the starting point at any time during forward traveling An object of the present invention is to provide a battery control device.

The battery controller for an electric vehicle according to the aspect of the present invention controls the discharge current and the regenerative current of the secondary battery for driving an electric vehicle that travels on the forward path from the starting point to the destination and returns to the starting point using the forward path as the return path. In the battery control device for an electric vehicle, a gradient sensor that detects a degree of road gradient for each predetermined travel distance from the starting point, a running speed of the electric vehicle, a degree of road gradient, a discharge current, and a regenerative current, And a memory for storing the degree of road gradient at the travel distance from the starting point in the memory, and at the same time, storing in the memory for each predetermined travel distance from the starting point. Data on the degree of slope of the road in the travel distance from the starting point, the traveling speed of the electric vehicle, the degree of slope of the road, the discharge current stored in the memory in advance, It is the battery control device for an electric vehicle for calculating the power capacity of the driving battery required to return to the starting point from the relationship between the raw current.

According to the present invention, on the premise that the outward road and the return road pass through the same road, not only the discharge current from the secondary battery and the regenerative current to the battery, but also the road gradient is taken into consideration, and further, when traveling on the forward road, By calculating the power consumption required to travel from the time point to the starting point, it is possible to provide a battery control device for an electric vehicle that can notify the driver at which point during the traveling on the way it is not possible to return to the starting point.

It is a block diagram of the battery control apparatus for electric vehicles which concerns on 1st Embodiment of this invention. It is a figure which shows the relationship between the travel distance and gradient in the outward path in embodiment of this invention. It is a figure which shows the relationship between the travel distance and the gradient in the return path in embodiment of this invention. It is a figure which shows the relationship between the gradient and electric current in embodiment of this invention. It is a block diagram of the battery control apparatus for electric vehicles which concerns on 2nd Embodiment of this invention. It is a block diagram of the battery control apparatus for electric vehicles which concerns on 3rd Embodiment of this invention. It is a block diagram for the conventional travelable distance calculation.

  Hereinafter, the battery control apparatus for electric vehicles which concerns on 1st Embodiment of this invention is demonstrated with reference to drawings.

FIG. 1 shows a configuration of a battery pack 1 including an electric vehicle battery control device. The battery pack 1 is mounted on an electric vehicle (not shown), acquires data related to braking force and travel distance information from the electric vehicle side, and outputs data related to remaining battery capacity and travelable distance to the electric vehicle side.

In the battery pack 1, a plurality of single cells 4 are connected in series between a positive electrode terminal 2 and a negative electrode terminal 3, and a charge control circuit 5 and a discharge control circuit 6 are provided on the positive electrode terminal 2 side. On the side, a current measuring circuit 7 is provided.

The voltage measurement circuit 8 measures the voltage value of each unit cell 4 and outputs the measurement voltage to the MPU 9 that performs charge / discharge control of the battery pack 1.

  The current measuring circuit 7 measures the charging current value and the discharging current value of the battery pack 1 and outputs the measured values to the MPU 9. The MPU 3 inputs brake force and travel distance information via the input port 10 from the electric vehicle side that is outside the battery pack 1. The MPU 9 controls charging and discharging of the battery pack 1 based on each input information. Specifically, at the time of charging, a charging switching circuit (not shown) in the charging control circuit 5 is controlled to control the charging current. Further, at the time of discharging, a discharge switching circuit (not shown) in the discharge control circuit 6 is controlled to control the discharge current.

A gradient sensor 11 and a memory 12 are provided in the battery pack 1, and the gradient sensor 11 measures the gradient of the traveling road and sequentially outputs gradient data to the MPU 9. The MPU 9 outputs data presented to the driver, such as the remaining battery capacity, the travelable distance, and the return alarm, through the output port 13 to the electric vehicle side. Further, the battery pack 1 is provided with a power supply circuit 14 that supplies power to each circuit and the like, and a communication I / F 15 that performs communication with the outside. Further, a temperature measuring circuit (not shown) is provided.

In FIG. 1, the voltage measurement circuit 8 measures the voltage of each unit cell 4 constituting the battery module and gives voltage information to the MPU 9. The MPU 9 controls the charge control circuit 5 and the discharge control circuit 6 using the voltage information of the unit cell 4 to turn on / off the charge switching circuit and the discharge switching circuit not shown in the figure to the battery module. The charging current and the discharging current from the battery module are controlled.

When the electric vehicle starts traveling and the battery module starts discharging, the MPU 9 acquires travel distance information as needed, continuously acquires road gradient information from the gradient sensor 11, and associates the travel distance with the gradient. Road gradient data is stored in the memory 12.

2A and 2B show typical examples of road gradient data. 2A and 2B, the horizontal axis indicates the distance from the starting point 0 or the elapsed time, and the vertical axis indicates the magnitude of the gradient. As already mentioned, the present invention is premised on going back the same way. FIG. 2A shows the forward path, FIG. 2B shows the return path, and as is clear from comparison between the two figures, the upstream path is the forward path and the downstream path is the downstream path.

As a result, the MPU 9 can acquire road gradient data with respect to the distance from the starting point.

The memory 12 stores in advance discharge current data and regenerative current data using road gradient and travel speed as parameters. As shown in FIG. 3, the horizontal axis indicates the road gradient, the vertical axis indicates the current consumption and the regenerative current, and shows the relationship between the gradient and current at each speed when climbing and descending.

The MPU 9 obtains road gradient data and stores the data in the memory 12 on the forward path, and at the same time calculates the amount of electric power and the travelable distance required when returning from the current time to the starting point 0 on the same route. The amount of power required to return from the current point in the forward path toward the starting point 0 toward the starting point 0 is obtained as follows. That is, the road gradient data on the forward path from the starting point 0 to the present time is read from the memory 12, and the road gradient is reversed between the forward path and the return path, so that the road gradient data of the return path as shown in FIG. Next, from the slope value at each time point in FIG. 2B and the data in FIG. 3, the current consumption or regenerative current value at each time point is obtained and integrated to obtain the electric energy required to return from the present time to the starting point 0. Is calculated. The MPU 9 calculates the amount of power required to return to the starting point 0 from the present time at any time on the forward path.

The MPU 9 sequentially calculates the remaining capacity P of the battery module and the power capacity Pv required to return to the starting point when arriving on the return path from the time point, and when P and Pv become equal, Display this to the driver. That is, when P and Pv are equal, it is impossible to return to the starting point unless the return route is reached. Since the MPU 9 does not return to the main starting point when traveling on the forward path, the MPU 9 sequentially displays the remaining capacity of the battery module and the amount of power required for the return path on a display (not shown), and the limit time point at which it can return to the starting point. Is displayed as a warning.

As described above, by having road gradient data, it is possible to calculate the amount of power used on the return road, that is, the distance that can be traveled, and the driver can determine whether or not the vehicle can return to the departure point. It is also possible to know the remaining battery capacity when returning to the starting point.

In FIG. 1, when calculating the travelable distance on the return road using the road gradient data, the regenerative current data using the road gradient and the traveling speed as parameters is acquired in advance, so that the downward gradient on the return road is obtained. The remaining capacity of the battery is calculated in consideration of the increase or decrease of the regenerative power depending on the grade of the gradient, and the travelable distance is calculated as needed using the remaining capacity. It is possible to notify the driver of the remaining capacity of the battery when returning to the starting point in advance.

In FIG. 1, when calculating the travelable distance on the return road using the road gradient data acquired on the outward path, the battery remaining capacity reaches an amount that can return to the starting point or immediately before the remaining capacity. In the description of the first embodiment described above, while acquiring road gradient data in the outward path in FIG. As stated, the distance that can be traveled when returning from the current point to the starting point is calculated and the remaining battery capacity can be reported to the driver. In order to notify the driver, the remaining battery capacity at that time is used to notify the driver of the distance that can be traveled from the current time on how far the vehicle can travel. In this case, since there is no gradient information of the road ahead from the current time on the forward path, the travelable distance is calculated from the remaining battery capacity and the travel speed on the assumption that the vehicle travels on a flat road.

In this way, the driver can know how far the vehicle can travel in the future in addition to the information on whether or not it is possible to return to the starting point from the current location.

In the present embodiment, the driver can arbitrarily set the starting point. The driver can arbitrarily set the main departure point of the forward path, that is, the acquisition start point of the road gradient data, for the MPU 9. In this embodiment, the point where the electric vehicle starts moving is not set as the starting point of the outward path, but the driver can arbitrarily inform the MPU 9 of the starting point.

FIG. 4 shows the configuration of this embodiment, which is obtained by adding input means 16 to the configuration shown in FIG. The simplest input means is a push button. As shown in FIG. 4, by using the input means 16 to the MPU 9 that can be operated by the driver at any time, the driver can arbitrarily specify the starting point, so that the starting point arbitrarily set on the return path It is possible to calculate the distance that can be traveled on the way back to and to know whether or not you can return to the starting point. For example, assuming such a case, it is easy to understand the effect of this embodiment. Suppose you take an electric car from your house garage, charge it at the nearest charging station, and drive to your destination. In this case, when starting the charging station, the starting point is notified to the MPU 9 by the input means 16, that is, the road gradient data is acquired and the calculation of whether or not to return to the starting point is started. When calculating the distance that can be traveled on the return road using the road gradient data acquired on the outbound route, when the remaining capacity of the battery reaches an amount that can be returned to the starting point or just before the remaining capacity, By notifying the driver, it is possible to reliably return to a place where charging is possible (a charging station set as a starting point).

When the electric vehicle travels on a flat road, the discharge current data stored in the memory 12 and the actual discharge current value detected by the current measurement circuit 7 are compared to thereby load the electric vehicle during travel. It can be determined whether or not the vehicle has increased or decreased from the reference value, and a change in running resistance due to a change in vehicle weight or a change in wind or road surface can be detected. As a result, it is possible to determine that the travelable distance increases or decreases with respect to the reference state.

In the present embodiment, the expensive gradient sensor 11 is not required and the configuration is simpler.

In FIG. 5, the input means 16 to the MPU 9 that can be operated by the driver at any time is used so that the driver can arbitrarily designate that the vehicle is currently traveling on a flat road. When the driver operates the input means 16 while traveling on a flat road, the MPU 9 stores in the memory 12 the discharge current at the time when it is designated that the road is flat as a reference value. Thereafter, the MPU 9 measures the road gradient by comparing the discharge current reference value on the flat road stored in the memory 12 with the actual discharge current value detected by the current measurement circuit 7.

By doing in this way, it becomes possible to measure the road gradient without using the expensive gradient sensor 11.

FIG. 5 shows a configuration in which the gradient sensor 11 is removed from FIG. The MPU 9 has discharge current data and regenerative current data with road gradient and travel speed stored in the memory 12 as parameters,
Measures the slope of the road that is currently running from the travel distance after starting travel, the acceleration / deceleration state, the discharge current value, the regenerative current value, the accelerator opening, the braking force, etc., input via the communication I / F 15 or the input port 10 To do.

By configuring in this way, it is possible to measure the state of the road gradient without using the gradient sensor 11 and to calculate the distance that can be traveled on the return path.

DESCRIPTION OF SYMBOLS 1 ... Battery pack, 4 ... Single cell, 5 ... Charge control circuit, 6 ... Discharge control circuit, 7 ... Current measurement circuit, 8 ... Voltage measurement circuit, 9 ... MPU, 10 ... Input port, 11 ... Gradient sensor, 12 ... Memory, 13 ... Output port, 14 ... Power supply circuit, 15 ... Communication I / F, 16 ... Input means

Claims (5)

In an electric vehicle battery control device that controls a discharge current and a regenerative current of a secondary battery for driving an electric vehicle that travels on a forward path from a starting point to a destination and returns to the starting point using the forward path as a return path.
A gradient sensor that detects the degree of gradient of the road for each predetermined travel distance from the starting point;
A memory storing in advance the relationship between the traveling speed of the electric vehicle, the degree of road gradient, the discharge current and the regenerative current;
The degree of road gradient at the travel distance from the departure point is stored in the memory, and at the same time, the road gradient at the travel distance from the departure point stored in the memory is stored for each predetermined travel distance from the departure point. The power of the driving secondary battery required for returning to the starting point from the relationship between the degree data and the traveling speed of the electric vehicle, the degree of road gradient, the discharge current and the regenerative current stored in advance in the memory A battery control device for an electric vehicle that calculates a capacity. Relationship between road grade data at the travel distance from the starting point stored in the memory and travel speed of the electric vehicle, road grade, discharge current and regenerative current stored in the memory in advance 2. The electric vehicle according to claim 1, wherein the driver is notified at a time limit when the power capacity required for the return road calculated from the above can be returned to the starting point.
Battery control device. 2. The battery control device for an electric vehicle according to claim 1, further comprising an input unit for arbitrarily setting the starting point. A means for inputting that the vehicle is traveling on a flat road is provided, and the road is determined from the difference between the reference discharge current and the actual discharge current based on the discharge current when the vehicle is traveling on a flat road. The battery control device for an electric vehicle according to claim 1, wherein the gradient of the electric vehicle can be measured. It is composed of a battery, a battery charge / discharge control means, a charge / discharge current measuring means, and a battery control means for controlling the above means. 2. The battery for an electric vehicle according to claim 1, wherein a road gradient can be calculated from a travel distance during actual travel, acceleration / deceleration state, discharge current value, regenerative current value, accelerator opening, brake force, and the like. Control device.

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