JPH08163705A - Battery remaining capacity display unit for electric vehicle - Google Patents

Abstract

PURPOSE: To display the remaining capacity of a battery in predetermined relation to the actual remaining capacity until it becomes empty despite the deteriorated state of the battery by integrating the discharge current of the battery from the first after the battery is charged, and comparing the threshold value of the battery power decrease with the battery power. CONSTITUTION: A voltmeter 2 monitors the voltage of a battery 1. An ammeter 3 monitors the current of the battery 1. The detection signals of the voltmeter 2 and the ammeter 3 are applied to a power detector 4 to monitor the present power of the battery 1. The signal of the ammeter 3 is also given to a discharge amount integrator 5 to monitor the discharge amount integrated value in each cycle. A comparator 7 decides that the charge of certain cycle is completed and after traveling, the battery power decreases from a threshold value, and stores the discharge amount integrated value Ic from the initial after this time charging. Thereafter, the battery is recharged, a remaining capacity display curve setter 9 decides this time full charge capacity from the Ic, and copes with between the full scale and the empty of a remaining capacity display meter 11.

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 the remaining battery capacity display device installed in the driver's seat accurately display the remaining battery capacity.

Therefore, conventionally, the current from the battery is measured, the integrated value of the current is obtained as the discharge amount integrated value, and as shown in FIG. 4, the discharge amount integrated from the dischargeable amount 2f at the time of full charge of a new product. The remaining capacity of the battery is obtained by subtracting the value, and the remaining capacity of the battery is displayed on the remaining battery capacity meter as a ratio of the dischargeable amount when fully charged to the full scale F.

However, when the remaining capacity of the battery decreases to some extent, the battery power is monitored so that the user can travel the distance D until returning to the nearest service station or home with the remaining capacity, and the battery power P is preset. When the threshold Th is exceeded, an alarm is issued, and after the threshold Th is exceeded, the remaining capacity becomes E when the vehicle travels a certain distance D regardless of the deterioration state of the battery. The remaining capacity is displayed with.

[0005]

However, in such a conventional battery remaining capacity display device for an electric vehicle, there is a difference between when the battery is fully charged and when it is deteriorated.
When the new product is new and the threshold value Th is below 1f as shown in FIG. 4 (a), if the deterioration progresses, the deterioration progresses to 1e. This is
When looking at the remaining capacity display from the driver's side, as shown in FIG. 4 (b), when the product is new, the remaining capacity indication goes down to point 1f and the alarm is first issued, but in the state where deterioration has progressed If the capacity indication becomes 1e, an alarm will be issued, and the driver thinks that there is still remaining capacity, but has made a distant trip, but the remaining capacity display suddenly begins to fall, so it is a hassle. It was supposed to end up.

The present invention has been made in view of the above-mentioned problems of the prior art, and is irrespective of the deterioration state of the battery.
It is an object of the present invention to provide a battery remaining capacity display device for an electric vehicle capable of displaying the remaining capacity in a fixed relationship with the actual remaining battery capacity until it becomes (empty).

[0007]

A battery remaining capacity display device for an electric vehicle according to the present invention comprises a discharge amount integrating portion for integrating the discharge current of the battery from the beginning after charging the battery,
A power detection unit that detects the power of the battery, a threshold setting unit that sets a threshold for battery power drop, a threshold set by the threshold setting unit, and a battery power that the power detection unit detects A comparison unit for comparison, a storage unit for storing the discharge amount integrated value accumulated by the discharge amount accumulation unit when the battery power detection value falls below a threshold value in the comparison of this comparison unit, and a storage unit for storing Calculate the allowable discharge amount after the next charge based on the discharge amount integrated value,
On the remaining capacity display curve setting part that sets the remaining capacity display curve that sets the discharge allowable amount to full scale, and the remaining capacity display curve set by the remaining capacity display curve setting part And a remaining capacity display section for displaying which position of the table corresponds to.

[0008]

In the battery remaining capacity display device for an electric vehicle of the present invention, the discharge current of the battery is accumulated by the discharge amount accumulator from the beginning after the battery is charged, and the power of the battery is detected by the power detector. Then, the comparison unit compares the battery power detection value with the threshold value given from the threshold value setting unit, and when the battery power detection value falls below the threshold value, the storage unit stores the discharge amount integrating unit by then. The accumulated discharge amount integrated value is stored.

After the battery is fully charged again, the remaining capacity display curve setting unit calculates the allowable discharge amount after the next charge based on the integrated discharge amount value stored in the storage unit. , Set the remaining capacity display curve that full-scales the permissible discharge amount, and the discharge amount integrated value at which the discharge amount integration unit started integration from the beginning after full charge corresponds to which position on the remaining capacity display curve Is displayed on the remaining capacity display.

As a result, even when the deterioration of the battery progresses, the remaining capacity is displayed in a constant relationship with the actual remaining capacity of the battery until the remaining capacity display section reaches E (empty).

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a block diagram of an embodiment of the present invention. A battery residual quantity display device for an electric vehicle of this embodiment comprises a voltmeter 2 for detecting a voltage of a battery 1, an ammeter 3 for detecting a current, A power detection unit 4 that detects battery power from the detection signals of the voltmeter 2 and the ammeter 3, and a discharge amount integration unit 5 that obtains a discharge amount integrated value of the battery 1 from the detection signals of the ammeter 3 are provided.

The battery remaining amount display device for an electric vehicle also includes a threshold value setting unit 6 for setting a threshold value for battery power reduction, and a threshold value setting unit 6 and a power detection unit 4. The comparing unit 7 that compares the detected battery power detection value with the discharge amount integrating unit 5 when the battery power detection value falls below the threshold value in the comparison of the comparing unit 7.
Is provided with a storage unit 8 that stores the accumulated discharge amount value accumulated up to that point.

Further, the allowable discharge amount after new charging is calculated with reference to the integrated discharge amount value stored in the storage unit 8, and the remaining capacity display curve is set to the full scale of the allowable discharge amount. The remaining capacity display curve setting unit 9 and the discharge amount integration value integrated by the discharge amount integration unit 5 are used as the remaining capacity display curve setting unit 9
The display control unit 10 for calculating which position on the remaining capacity display curve set by the display control unit 10 and the remaining capacity indicator 11 for displaying the remaining capacity by the remaining capacity display pointer based on the instruction of the display control unit 10. I have it.

Next, the operation of the battery remaining capacity display device of the electric vehicle having the above structure will be described. The voltmeter 2 monitors the voltage of the battery 1, the ammeter 3 monitors the current of the battery, supplies these detection signals to the power detection unit 4, and monitors the current power of the battery 1 here. The detection signal of the ammeter 3 is also given to the 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.

A power threshold is preset in the threshold setting unit 6.

When charging of a certain cycle is completed and the electric vehicle starts traveling, the power detection unit 4 constantly detects battery power, and the comparison unit 7 sets the power threshold set in the threshold value setting unit 6. Monitor for a drop before the value is cut. Then, as the traveling distance of the automobile increases, the battery power consumption increases, and when the battery power decreases, it eventually decreases until it falls below the threshold Th.

When the comparison unit 7 determines that the battery power has dropped below the threshold value Th (step S1 in the flowchart shown in FIG. 2), the storage unit 8 stores the discharge amount integration unit 5.
Stores the discharge amount integrated value Ic from the beginning after the current charging, which has been obtained until then (step S2).

When the threshold value Th is cut, the driver recognizes that the remaining capacity has decreased and moves to the nearest service station or a place where there is charging equipment such as a house. Then, when the vehicle arrives at that location and is recharged, and when the recharge is completed, a new cycle of traveling is started (step S3).

First, after the charging, the remaining capacity display curve setting unit 9 sets the current full charging capacity It to It = Ic + α, and the full charging capacity It is compared with the full scale F and the empty E on the remaining capacity indicator 11. (Step S4).

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

When the vehicle starts traveling again, the display control unit 10 uses the discharge amount integrated value Ic calculated by the discharge amount integrating 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 the remaining capacity indicator 11 is instructed to indicate the position corresponding to A. Based on this instruction, the remaining capacity indicator 11 moves the position A to the scale of the fully charged F-empty E, for example, if it is 0.7, the position 0.7 is slightly lowered from the F side. If it is 0.5, half the position is instructed (step S6).

As described above, in the battery residual capacity display device for an electric vehicle of this embodiment, as shown in FIG. 3A, the point at which the battery power falls below the threshold value Th when it is new is a1. If this is done, the discharge amount integrated value I at this point
a is obtained and stored, and the next full charge capacity is estimated as a value obtained by adding a constant α (area of a shaded portion in FIG. 3) to this 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 capacity of the battery is F− by subtracting the integrated value of the discharged capacity after charging from this full charge capacity.
Instruct on the E scale.

Therefore, as the discharge amount integrated value increases as the vehicle runs, the remaining capacity decreases on the straight line A in FIG. 3 (b). 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.

Comparing this display mode of the remaining capacity with the conventional one, in the state of deterioration, in the conventional case, the remaining capacity display at the time when the threshold Th is turned off is 1e as shown in FIG. 3 (b). However, according to this embodiment, the battery capacity is reduced more and more as the deterioration progresses. Will be able to predict where to become empty E while driving, and there will be no hassle.

The present invention is not limited to the above embodiment, but may have the following configurations. That is, the discharge current of the battery is accumulated from the beginning after the battery is charged by the discharge amount integrator 5, while the power of the battery is detected by the power detector 4 and the comparator is detected every time the vehicle is charged. In step 7, the battery power detection value is compared with the threshold value given from the threshold value setting section 6, and when the battery power detection value falls below the threshold value, the discharge amount integrating section 5 stores it in the storage section 8 every time. The accumulated discharge amount accumulated up to is stored.

After the battery is fully charged again, the remaining capacity integrated value stored in the storage unit 8 until then is averaged, and the remaining capacity display curve setting unit 9 averages the discharged amount. The discharge allowable amount after the next charge is calculated based on the integrated value, the remaining capacity display curve that sets the discharge allowable amount in full scale is set, and the discharge amount integrating unit 5 performs the integration from the beginning after the full charge. It is also possible to display on the remaining capacity indicator 11 which position on the remaining capacity display curve the discharge integrated value that has started corresponds to.

As a result, even if the deterioration of the battery progresses, the remaining capacity can be displayed at a certain relationship with the actual remaining capacity of the battery until the remaining capacity display section reaches E (empty). Even if there is a case where the battery power falls below the threshold value faster than it should be because the recharging of the battery was incomplete and did not reach full charge, it is possible to respond flexibly to it. Therefore, the reliability of the remaining capacity display can be further improved.

In the case of the above embodiment, the averaging process can use a simple average based on the number of times of charging up to that time. However, if the time until the power decreases as the deterioration progresses is accelerated, the charging is performed. It is also possible to use a weighted average depending on the number of times.

[0029]

As described above, according to the present invention, the discharge current of the battery is accumulated by the discharge amount accumulator from the beginning after the battery is charged, while the power of the battery is detected by the power detector. In the comparison unit, the battery power detection value is compared with the threshold value given from the threshold value setting unit, and when the battery power detection value falls below the threshold value, the storage unit accumulates the discharge amount by that time. Is stored, and after the battery is newly fully charged, the remaining capacity display curve setting unit is allowed after the next charge based on the discharge amount integrated value stored in the storage unit. Calculate the discharge allowable amount, set the remaining capacity display curve that is the discharge allowable amount in full scale, and start the integration from the beginning after the full charge by the discharge amount integration unit.The discharge amount integrated value is displayed on the remaining capacity display curve. Since the remaining capacity display section displays which position is applicable, even when the battery deterioration progresses, the remaining capacity display is displayed in a fixed relationship with the actual remaining battery capacity until the remaining capacity display section becomes empty. This allows the driver to predict where the empty E will be while driving by looking at the remaining capacity display regardless of the deterioration state of the battery. Thus, the remaining capacity display pointer rapidly advances rapidly so that there is no need to panic and the reliability of the remaining capacity display can be improved.

[Brief description of drawings]

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

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

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

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

[Explanation of symbols]

 1 Battery 2 Voltmeter 3 Ammeter 4 Power Detection Section 5 Discharge Amount Integration Section 6 Threshold Setting Section 7 Comparison Section 8 Storage Section 9 Remaining Capacity Display Curve Setting Section 10 Display Control Section 11 Remaining Capacity Display Meter

Claims (1)

[Claims] 1. A discharge amount integration unit that integrates a discharge current of the battery from the beginning after charging the battery, a power detection unit that detects the power of the battery, and a threshold value that sets a threshold value of battery power reduction. In the comparison of the setting unit, the threshold value set by the threshold value setting unit and the battery power detected by the power detection unit, and in the comparison of the comparison unit, the battery power detection value is the threshold value. When the battery is turned off, a storage unit that stores the integrated discharge amount value accumulated by the discharge amount integration unit, and the allowable discharge amount after the next charge based on the integrated discharge amount value stored in the storage unit And the remaining capacity display curve setting unit that sets the remaining capacity display curve that sets the discharge allowable amount to full scale, and the remaining capacity display curve setting unit that sets the discharge amount integrated value that the discharge amount integrating unit integrates. And a battery remaining capacity display device for an electric vehicle, comprising: a remaining capacity display unit that displays which position on the remaining capacity display curve.