JP3360446B2 - Battery display device for electric vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery remaining capacity display device for an electric vehicle.

[0002]

2. Description of the Related Art Since an electric vehicle uses a battery as a driving source, it is desired that a remaining battery capacity display device installed in a driver's seat accurately display the remaining battery capacity.

[0003] Conventionally, a current flowing from a battery is conventionally measured, and an integrated value of the current is obtained as a discharge amount integrated value, and as shown in FIG. The remaining capacity of the battery is obtained by subtracting the value, and the remaining capacity is displayed on the battery remaining capacity meter as a ratio of the dischargeable amount at full charge to the full scale F.

[0004] However, when the remaining capacity of the battery is reduced to some extent, the battery power is monitored so that the vehicle can travel the distance D until returning to the nearest service station or home with the remaining capacity, and the battery power P is set in advance. A warning is issued when the threshold value Th falls below the threshold value. After the threshold value Th is dropped, the remaining capacity becomes E when the vehicle travels a certain distance D regardless of the state of deterioration of the battery. Displays the remaining capacity.

[0005]

However, in such a conventional battery remaining capacity display device for an electric vehicle, even when the battery is fully charged, it is difficult to determine whether the battery is new or deteriorated.
When the power drops differently, as shown in FIG. 4 (a), when the threshold value Th is cut off at the point 1f at the time of a new product, the deterioration is advanced to the point 1e as the deterioration proceeds. This means
Looking at the remaining capacity display from the driver side, as shown in FIG. 4 (b), when the product is new, a warning is issued only after the remaining capacity instruction is lowered to the point 1f. If the capacity instruction becomes 1e, an alarm will be issued, and the driver will think that there is still remaining capacity and go away, but the display of the remaining capacity will suddenly drop, and the driver will be in a hurry. Was supposed to.

[0006] The present invention has been made in view of such a conventional problem, and regardless of the state of deterioration of the battery, the E / E
It is an object of the present invention to provide a battery remaining capacity display device for an electric vehicle which can display a remaining capacity in a fixed relationship with the actual remaining battery capacity until the battery becomes empty.

[0007]

According to the present invention, there is provided a battery remaining capacity display device for an electric vehicle, comprising: a discharge amount accumulating unit for accumulating a discharge current of the battery from the beginning after the battery is charged;
A power detection unit that detects battery power; a threshold setting unit that sets a threshold for battery power reduction; and a threshold set by the threshold setting unit and battery power detected by the power detection unit. A comparing section to be compared, a storage section for storing the discharge amount integrated value accumulated by the discharge amount integrating section when the battery power detection value falls below the threshold value in the comparison of the comparing section, and a storage section for storing Calculate the allowable discharge amount after the next charge based on the integrated discharge amount value,
A remaining capacity display curve setting unit that sets a remaining capacity display curve in which the permissible discharge amount is set to a full scale, and a remaining capacity display curve set by a remaining capacity display curve setting unit that integrates a discharge amount integrated value calculated by the discharge amount integrating unit. And a remaining capacity display unit for displaying which position corresponds to the remaining capacity.

[0008]

In the battery remaining capacity display device for an electric vehicle according to the present invention, the discharging current of the battery is integrated from the beginning after the charging of the battery by the discharging amount integrating unit, while the power of the battery is detected by the power detecting unit. The comparison unit compares the detected battery power value with a threshold value provided from the threshold value setting unit. When the detected battery power value drops below the threshold value, the storage unit stores the discharge amount integration unit in the storage unit. The integrated discharge amount value is stored.

After the battery is newly fully charged, the remaining capacity display curve setting unit calculates the allowable discharge amount after the next charge based on the integrated discharge amount stored in the storage unit. The remaining capacity display curve in which the discharge allowable amount is set to full scale is set, and the discharge amount integrated value at which the discharge amount integrating unit starts integration from the beginning after full charge corresponds to any position on the remaining capacity display curve Is displayed on the remaining capacity display section.

Thus, even if the battery deteriorates, the remaining capacity is displayed on the remaining capacity display section in a fixed relationship with the actual remaining battery capacity until E (empty).

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the present invention. A battery remaining amount display device for an electric vehicle according to this embodiment includes a voltmeter 2 for detecting a voltage of a battery 1, an ammeter 3 for detecting a current, A power detection unit 4 for detecting battery power from the detection signals of the voltmeter 2 and the ammeter 3 and a discharge amount integration unit 5 for obtaining a discharge amount integrated value of the battery 1 from the detection signal of the ammeter 3 are provided.

The battery remaining amount display device of the electric vehicle also includes a threshold value setting section 6 for setting a threshold value for battery power reduction, a threshold value set by the threshold value setting section 6 and a power detection section 4. A comparing unit 7 for comparing the detected battery power detection value with the detected battery power detection value;
Is provided with a storage unit 8 for storing the integrated discharge amount value up to that time.

Further, based on the integrated discharge amount stored in the storage unit 8, a discharge allowable amount allowed after a new charge is calculated, and a remaining capacity display curve in which the discharge allowable amount is set to a full scale is set. The remaining capacity display curve setting section 9 and the remaining capacity display curve setting section 9 calculate the discharge amount integrated value integrated by the discharge amount integrating section 5.
A display control unit 10 for calculating which position on the remaining capacity display curve is set, and a remaining capacity indicator 11 for displaying the remaining capacity according to the remaining capacity display pointer based on the instruction of the display control unit 10. Have.

Next, the operation of the battery remaining capacity display device for an electric vehicle having the above configuration will be described. The voltmeter 2 monitors the voltage of the battery 1, the ammeter 3 monitors the current of the battery, and supplies these detection signals to the power detection unit 4, where the current power of the battery 1 is monitored. The detection signal of the ammeter 3 is also supplied to a discharge amount integrating section 5, where the discharge amount from the beginning after charging the battery is integrated and the integrated value of the discharge amount in each cycle is monitored.

In the threshold setting section 6, a power threshold is set in advance.

Therefore, when the charging of a certain cycle is completed and the electric vehicle starts running, the power detection unit 4 always detects the battery power, and the comparison unit 7 sets the power threshold set in the threshold setting unit 6. Monitor for any drop before dropping. Then, as the traveling distance of the vehicle increases, the consumption of the battery power progresses, and when the battery power decreases, the battery power eventually decreases before the threshold value Th is reduced.

If the comparing section 7 determines that the battery power has dropped below the threshold Th (step S1 in the flowchart shown in FIG. 2), the storage section 8 stores the discharge amount integrating section 5
Store the integrated amount of discharge Ic from the beginning after the current charge obtained so far (step S2).

When the threshold value Th is reduced, the driver recognizes that the remaining capacity is low, and moves to the nearest service station or a place where a charging facility such as a house is located. Then, the vehicle arrives at the place, performs recharging, and when the recharging is completed, the running of a new cycle is started (step S3).

First, after the charge, the remaining capacity display curve setting section 9 sets the current full charge capacity It to It = Ic + α, and sets the full charge capacity It to the full scale F and the empty E in the remaining capacity indicator 11. (Step S4).

Here, α is a constant, which is an electric quantity corresponding to the distance D that can travel after the threshold value shown in FIG. 3 has been cut, and is constant regardless of the deterioration state of the battery 1.

When the vehicle starts running again, the display control unit 10 uses the discharge amount integrated value Ic calculated by the discharge amount integration unit 5 and the current full charge capacity It to display the full scale F in the remaining capacity indicator 11. Is calculated based on the proportional expression of A = (It−Ic) / It, and a command is given to the remaining capacity indicator 11 to indicate the position corresponding to A. Then, based on this instruction, the remaining capacity indicator 11 indicates the position of A with respect to the scale of the full charge F-empty E, for example, if it is 0.7, the position of 0.7 slightly lowered from the F side. If it is 0.5, it indicates a half position (step S6).

As described above, in the battery remaining capacity display device of the electric vehicle according to this embodiment, as shown in FIG. 3A, the point at which the battery power falls below the threshold value Th at the time of a new product is a1. Then, the discharge amount integrated value I at this time is
a is calculated and stored, and the next full charge capacity is estimated to be a value obtained by adding a constant α (the area of a shaded portion in FIG. 3) to the discharge amount integrated value Ia, that is, Ia + α,
This Ia + α is used as the full scale F in the remaining capacity indicator 11, and the current remaining battery capacity is calculated by subtracting the discharge capacity integrated value after charging from this full charge capacity.
Indicate on the E scale.

Therefore, as the integrated value of the discharge amount increases as the vehicle travels, the remaining capacity decreases on the straight line A in FIG. 3B. Similarly, when the deterioration progresses to some extent, the remaining capacity decreases on the straight line B, and when the deterioration further progresses, the remaining capacity decreases on the straight line C.

When this display mode of the remaining capacity is compared with the conventional one, in the state where deterioration has progressed, if the power is cut off the threshold value Th as shown in FIG. However, according to this embodiment, as the deterioration progresses, the battery capacity decreases faster as a whole, Makes it possible to predict where the vehicle will be empty E while driving, so that it will not panic.

It should be noted that the present invention is not limited to the above-described embodiment, and may have the following configuration. That is, while the discharge current of the battery is integrated from the beginning after the battery is charged by the discharge amount integration unit 5, the power of the battery is detected by the power detection unit 4 and the comparison unit is used for each run after each charge. 7, the battery power detection value is compared with a threshold value provided from the threshold value setting unit 6, and when the battery power detection value falls below the threshold value, the discharge amount integrating unit 5 is stored in the storage unit 8 every time. The accumulated discharge amount values accumulated up to this point are stored.

After the battery is newly fully charged, the remaining capacity integrated value stored in the storage unit 8 is averaged, and the remaining capacity display curve setting unit 9 calculates the averaged discharge amount. Based on the integrated value, the allowable discharge amount after the next charge is calculated, a remaining capacity display curve is set in which the allowable discharge amount is set to a full scale, and the discharge amount integrating unit 5 performs integration from the beginning after full charge. The position on the remaining capacity display curve where the started discharge amount integrated value corresponds can be displayed by the remaining capacity indicator 11.

As a result, even if the battery deteriorates, not only can the remaining battery capacity be displayed in a fixed relationship with the actual remaining battery capacity until the remaining battery capacity becomes E (empty), but also at a certain point in time. If the recharge of the battery is incomplete and did not reach full charge, the next time the battery power drops below the threshold may occur faster than it should be. The reliability of the remaining capacity display can be further improved.

In the case of the above-described embodiment, the averaging process can use a simple average based on the number of chargings up to that point. A load average according to the number of times can also be used.

[0029]

As described above, according to the present invention, the discharge current of the battery is integrated by the discharge amount integration unit from the beginning after the battery is charged, while the power of the battery is detected by the power detection unit. The comparison unit compares the detected battery power value with a threshold value provided from the threshold value setting unit, and when the detected battery power value falls below the threshold value, the discharge amount integrating unit integrates the data into the storage unit. After the battery has been newly fully charged, the remaining capacity display curve setting unit stores the accumulated discharge amount value, and the remaining capacity display curve setting unit is permitted after the next charge based on the accumulated discharge amount value stored in the storage unit. Calculate the allowable discharge amount, set a remaining capacity display curve in which the allowable discharge amount is set to a full scale, and calculate the discharge amount integrated value from the beginning after the full charge by the discharge amount integrating unit. Since the remaining position is indicated by the remaining capacity display, even if the battery deteriorates, the remaining capacity is displayed in a constant relationship with the actual remaining battery capacity until the remaining capacity display becomes empty. It is possible for the driver to predict where the vehicle will be empty E while watching the remaining capacity display, regardless of the state of deterioration of the battery, and to make a prediction while driving, as in the prior art. As a result, the remaining capacity display pointer rapidly advances so that it does not panic, and the reliability of the remaining capacity display can be increased.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of one embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment.

FIG. 3 is a timing chart showing the operation of the embodiment.

FIG. 4 is a timing chart showing the operation of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery 2 Voltmeter 3 Ammeter 4 Power detection unit 5 Discharge amount integration unit 6 Threshold value setting unit 7 Comparison unit 8 Storage unit 9 Remaining capacity display curve setting unit 10 Display control unit 11 Remaining capacity display meter

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60L 3/00 G01R 31/36 H02J 7/00

Claims (1)

(57) [Claims] 1. A discharge amount integrating section for integrating a discharge current of a battery from the beginning after charging a battery, a power detecting section for detecting power of the battery, and a threshold value for setting a threshold value of battery power reduction. A setting unit, a comparison unit that compares a threshold value set by the threshold value setting unit with a battery power detected by the power detection unit, and wherein the comparison unit compares the battery power detection value with the threshold value. And a storage unit for storing the integrated discharge amount value accumulated by the discharge amount integrating unit, and a discharge allowable amount allowed after the next charge based on the integrated discharge amount value stored in the storage unit. And a remaining capacity display curve setting unit that sets a remaining capacity display curve in which the allowable discharge amount is set to full scale, and a remaining capacity display curve setting unit that sets a discharge amount integrated value integrated by the discharge amount integrating unit. And a remaining capacity display unit for displaying which position on the remaining capacity display curve corresponds to the remaining battery capacity of the electric vehicle.