JP2001166019A - Charged condition deciding device for battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably and easily distinguish the fully charged condition of a battery 3. SOLUTION: If the voltage of a battery 3 detected by a voltage sensor 8 exceeds a designated value, and a difference between a generated current detected by a first current sensor 6 and a current consumption detected by a second current sensor 7 is within a designated value, the battery is decided by an ECU 5 to be fully charged. A fully charged condition is decided by the voltage of the battery 3 and the current charged by the battery 3, and the fully charged condition is distinguished reliably and easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery state-of-charge judging device for judging a fully charged state of a battery.

[0002]

2. Description of the Related Art For example, a vehicle is equipped with various electric devices (electric loads) such as lamps, a drive motor for driving an air conditioning blower and a power device, and the electric power consumed by the electric devices is sufficient. Powered by a dischargeable battery. On the other hand, a vehicle is equipped with a generator (alternator) driven by an engine, and a battery is charged by operation control of the alternator to secure a capacity.

[0003] In recent years, in consideration of environmental problems, various hybrid electric vehicles in which an electric motor and an engine are combined, and vehicles in which the engine is stopped when the vehicle is stopped such as at a signal stop and the engine is forcibly started when the vehicle is started have been developed. Is coming. In such an automobile, it is necessary to accurately grasp the remaining capacity (charged state) of the battery. For example, by accurately grasping the full charge of the battery, useless charging such as driving the alternator more than necessary can be avoided.

Conventionally, in order to grasp the full charge state of a battery, the amount of charge power is determined by the product of the charge current and the predicted discharge voltage, and the determined charge power is added to the remaining battery charge.
There is known a technique for determining whether or not the battery has been fully charged by repeating a process of obtaining the added value as a new remaining capacity (for example, see Japanese Patent Application Laid-Open No. 6-167551). By accumulating the charging power amount, it is possible to grasp the full charge state of the battery.

[0005]

However, the charging efficiency of the battery changes due to the temperature environment, individual differences, aging, and the like, and the amount of charging power required until the battery is fully charged changes.
For this reason, in the technology that relies on the conventional calculation, there is a problem that the full charge state cannot be reliably determined. Further, since the charging power amount is integrated, measurement errors and the like are accumulated in the calculation process, so that the reliability is lacking. There was a problem.

[0006] In order to make the full charge determination more reliable by the conventional technique of integrating the amount of charge power, a complicated correction process for eliminating the effects of temperature environment, individual differences, aging, accumulated errors, and the like is required. At the same time, there is a problem that a large number of man-hours are required for the matching of the processing programs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a battery state-of-charge determining apparatus capable of reliably and easily determining the full state of charge of a battery.

[0008]

In order to achieve the above object, according to the present invention, while the generator is operating, the voltage of the battery detected by the battery voltage detecting means is equal to or higher than a predetermined value and the generated current detecting means detects the battery voltage. When the difference between the detected power generation current and the consumption current detected by the consumption current detection means is within a predetermined value, the full charge determination means determines that the battery is in the fully charged state, and the battery is reliably and simply charged. The full charge state is determined.

At this time, it is preferable that the battery is fully charged when a state in which the voltage of the battery is equal to or higher than a predetermined value and a difference between the generated current and the consumed current is equal to or less than a predetermined time continues for a predetermined time or more. It is determined that there is.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration of a vehicle provided with a battery state-of-charge judging device according to an embodiment of the present invention, FIG. 2 is a control flowchart of a full charge judging means, and FIG. A time chart of voltage and current is shown.

As shown in FIG. 1, a generator (alternator) 2 driven by a crankshaft of an engine 1 is provided. The alternator 2 issues a command from an ECU 5 according to the status of a battery 3 and an electric load 4 of various electric devices. The power generation amount is controlled based on The state of the alternator 2 is not shown in FR
A terminal is input to the ECU 5, and a power generation control duty signal (G terminal Duty) is output from the ECU 5 to a G terminal (not shown) according to the state of the battery 3 and the electric load 4. G terminal Duty is 0% of the minimum generated power to 10% of the maximum
Controlled between 0%.

The battery 3 is chargeable and dischargeable. The battery 3 is supplied with electric power from the alternator 2 to be charged, and the electric load 4 is appropriately supplied with electric power from the alternator 2 and the battery 3. On the path from the alternator 2 to the battery 3, a first current sensor 6 is provided as a generated current detecting means, and the generated current of the alternator 2 is detected by the first current sensor 6. In addition, a second current sensor 7 as a current consumption detecting means is provided on a path from the battery 3 to the electric load 4 on the electric load 4 side of the first current sensor 6, and the second current sensor 7 uses Current is detected. The battery 3 is provided with a voltage sensor 8 as a battery voltage detecting means.
The voltage of the battery 3 is detected by the voltage sensor 8.

Detection signals from the first current sensor 6, the second current sensor 7, and the voltage sensor 8 are input to the ECU 5. EC
In U5, the alternator 2 is operating and the battery 3
Full charge determining means for determining that the battery 3 is in a fully charged state when the state where the voltage of the battery 3 is equal to or more than a predetermined value and the difference between the generated current and the consumed current continues for a predetermined time or more. I have.

In the above-described vehicle, for example, no power is generated during acceleration, and the difference between the consumed current detected by the second current sensor 7 and the generated current detected by the first current sensor 6 becomes zero during steady running. Thus, the power generation of the alternator 2 is controlled. That is, the G terminal Duty is controlled between 0% of the minimum generated power and 100% of the maximum generated power, and power is generated at a required voltage. In addition, at the time of deceleration, the G terminal Duty is set to 100%, power is generated at the maximum power generation voltage, and deceleration energy is recovered. Also,
If the vehicle has a function of stopping the engine when idling while stopping and automatically starting the engine when starting, the second current sensor is used during stopping to prevent the engine from being restarted during stopping. Alternatively, the battery 1 may be charged by starting the engine 1 as appropriate based on the current consumption detected by the generator 7 and generating electricity by the alternator 2.

When the battery 3 is charged by the alternator 2 and the battery 3 is fully charged by the full charge determination means of the ECU 5, the G terminal
Duty is reduced to suppress the power generated by the alternator 2. As a result, it is possible to avoid useless charging in which charging is performed even when the battery is fully charged.

The means for judging full charge will be described in detail with reference to FIGS.

In step S1, it is determined whether or not the charging request flag is set, that is, whether or not there is a charging request. If the charging request flag is set and it is determined that there is a charging request ( The power generation is performed when the G terminal Duty is 100%: the generator is operating), the voltage value V of the battery 3 detected by the voltage sensor 8 in step S2.
It is determined whether _B (V) is equal to or higher than a predetermined voltage value K _VB (V) which is a predetermined value. If it is determined in step S1 that the charge request flag has not been set, the process returns.

In step S2, the voltage value V of the battery 3
_If it is determined that _B (V) is equal to or higher than the predetermined voltage value K _VB (V), the consumed current value detected by the second current sensor 7 and the generated current value detected by the first current sensor 6 in step S3. It is determined whether or not the difference (current consumption value-generation current value) ΔI (A) is equal to or more than the lower limit value K _IL (A) and equal to or less than the upper limit value K _IH (A) (within a predetermined value). Here, as shown in FIG. 3, the lower limit value K _IL (A) is on the minus side (for example, −6 A).
And the upper limit value K _IH (A) is set slightly to the plus side (for example, + 1A).

In step S3, the difference ΔI (A) is reduced to the lower limit value K _IL
If it is determined that the value is not less than the upper limit value K _IH (A), the count value TMR of the charge termination determination confirmation timer is subtracted in step S4 to obtain a count value (TMR -1). The initial value of the count value TMR of the charge end determination confirmation timer is Tse
c (for example, 60 seconds). After setting the count value TMR of the charging end determination timer to TMR-1 in step S4, in step S5, it is determined whether the new count value TMR has become 0, that is, whether a predetermined time Tsec (for example, 60 seconds) has elapsed. Is determined.

In step S2, the voltage value V of the battery 3
_{When it} is determined that _B (V) is not equal to or higher than the predetermined voltage value K _VB (V), and in step S3, the difference ΔI (A) is equal to or higher than the lower limit value K _IL (A) and equal to or lower than the upper limit value K _IH (A). If it is determined that it is not the same, the count value TMR of the charge end determination confirmation timer is set as the initial value _KINT in step S6, and the process _proceeds to step S5.

If it is determined in step S5 that the count value TMR of the charging completion determination timer has become 0, the charging request flag is reset and the charging flag is set in step S7 to determine that the battery is fully charged. That is, as shown in FIG. 3, the voltage value V _B (V) of the battery 3 becomes equal to or higher than the predetermined voltage value K _VB (V) (t1 in the figure), and the difference ΔI (A) between the generated current and the consumed current is the lower limit. Upper limit value K _IH above value K _IL (A)
(A) When the state (t2 or later) in the figure or less continues for a predetermined time (for example, 60 seconds) (t3 in the figure), it is determined that the battery is fully charged.

If the charging request flag is not set in step S1 and if it is determined in step S5 that the count value TMR of the charging completion determination timer is not 0, the routine returns.

Here, when the full charge state is determined, the predetermined value of the difference ΔI (A) between the generated current and the consumed current is basically set to the side where the generated current is large (minus side). In the embodiment, from the side where the current consumption is slightly higher (upper limit K _IH on the plus side) to the side where the generated current is higher (lower limit K on the minus side)
_IL ).

This is because when the apparatus of the present embodiment is applied to a vehicle in which the alternator 2 is driven by the engine 1, fluctuations in idle speed of the engine 1 (particularly in a low rotation speed range), gear changes of a transmission, Since the generated current may be instantaneously reduced due to the influence of the gear ratio or the like, or the rotation fluctuation at the time of returning from the fuel cut, the upper limit value K _IH is slightly increased (plus side). Is set, and when the battery is instantaneously discharged, the count value of the charge termination determination confirmation timer can be continuously reduced. Thus, when the current consumption becomes larger than the generated current instantaneously in spite of the continuation of the charge state, the discharge state is not determined, and the full charge state can be reliably determined.

The difference ΔI (A) between the generated current and the consumed current
The predetermined value can always have a width on the side where the generated current is large (minus side: including 0), or can always have a width on the side where the consumed current is slightly large (plus side). Even if the predetermined value of the difference ΔI (A) between the generated current and the consumed current is slightly increased (positive side), the voltage value V _B (V) of the battery 3 increases if the state of large consumed current continues. The voltage decreases and becomes less than the predetermined voltage value K _VB (V) (indicated by the two-dot chain line in FIG. 3), and it is determined as NO in step S2. For this reason,
It is not determined that the battery 3 is fully charged while the state where the current consumption is large continues.

In the above-described state-of-charge determination device, when the voltage value V _B (V) of the battery 3 is equal to or higher than the predetermined voltage value K _VB (V),
And the difference ΔI (A) between the generated current and the consumed current is the lower limit K
_If the state that is equal to or higher than _IL (A) and equal to or lower than the upper limit value K _IH (A) continues for a predetermined time (for example, 60 seconds), it is determined that the battery is fully charged, that is, from the voltage of the battery 3 and the current to be charged, Since the full charge state is determined, the full charge state can be determined without being affected by the temperature environment of the battery 3, individual differences, aging, accumulated errors, and the like, and without using complicated control.

In the above-described embodiment, the full charge state is determined when the voltage of the battery 3 exceeds a predetermined value and the difference between the generated current and the consumed current is within a predetermined value range for a predetermined time or more. However, by appropriately selecting a predetermined value of the voltage and a predetermined value range of the difference between the generated current and the consumed current, it is also possible to determine the fully charged state without continuing for a predetermined time or more. In addition, the charge state determination device of the above embodiment has been described with reference to an example applied to a vehicle, but is limited to application to a vehicle as long as the device or device includes a generator that supplies power to a battery and an electric load. It is not something to be done.

[0028]

According to the battery state-of-charge judging device of the present invention, when the battery voltage exceeds a predetermined value and the difference between the generated current and the consumed current is within the predetermined value, it is determined that the battery is fully charged. Therefore, the full charge state can be determined from the battery voltage and the current charged in the battery. As a result, it is possible to reliably and easily determine the full charge state of the battery without using complicated control without being affected by the temperature environment of the battery, individual differences, aging, and accumulated errors.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a vehicle including a battery charge state determination device according to an embodiment of the present invention.

FIG. 2 is a control flowchart of a full charge determination unit.

FIG. 3 is a time chart of voltage and current.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Generator (alternator) 3 Battery 4 Electric load 5 ECU 6 1st current sensor 7 2nd current sensor 8 Voltage sensor

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Hiroyuki Yamada 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation F-term (reference) 2G016 CA03 CB12 CB21 CB31 CC01 CC04 CC27 5H115 PG04 PI16 PI22 PI30 PO17 QA01 QA05 QE10 QI04 QN12 SE02 SE06 TI01 TI05 TI06 TO12 TR19

Claims (1)

[Claims] A generator for supplying power to a battery and an electric load; a battery voltage detector for detecting a voltage of the battery; a current consumption detector for detecting a current consumption of the electric load; And a generator current detecting means for detecting when the battery is operating and the voltage of the battery is equal to or higher than a predetermined value and the difference between the generated current and the consumed current is within a predetermined value. A battery state-of-charge judging device comprising: a full-charge judging means for judging a state of charge.