JP2524867B2 - Battery status detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage battery state detecting device for predicting the capacity reduction and life state of an automobile storage battery and improving the reliability of the battery.

2. Description of the Related Art Recently, storage battery troubles due to traffic congestion on expressways have rapidly increased, and sudden engine stoppages or start-up troubles on expressways have become a serious problem. This is because the load on the vehicle has increased sharply compared to the battery capacity and alternator capacity of recent vehicles. In order to prevent such battery-related troubles, each manufacturer is developing a storage battery state detecting device.

The in-vehicle load with respect to the amount of power generated by the alternator is increasing year by year, and there is a possibility that the charge / discharge balance of the battery may be greatly disturbed depending on the running state of the vehicle, and battery troubles are likely to occur. For example, when driving during a night traffic jam in summer, the amount of power generated by the alternator cannot cover the load,
Eventually the battery will be completely discharged, the engine will stop and it will not be possible to restart. Also, recently, due to the increase in heat generation sources in the engine room and the lack of inflow of outside cool air due to changes in automobile technology such as electronics, the atmosphere in the engine room becomes hot when idling in the summer hot weather, and the capacity of the alternator increases. Along with the increase in charge, the deterioration of battery performance has become a problem.

As described above, there is an urgent social need to develop a detection device capable of accurately monitoring the capacity state and deterioration state of a battery during traveling and preventing the above-mentioned troubles caused by the battery.

Means for Solving the Problems The storage battery state detection device according to the present invention can be reversible with this voltage as a boundary when the voltage value toward the charged state is reached during traveling including idling, or when the voltage value drops toward the discharged state. A timer is configured so that when the voltage above the voltage value that is the state of charge continues for a certain period of time or more, the timer time can be reset to a predetermined time corresponding to the certain period, after which the on-vehicle load is turned on. The timer is driven when the voltage drops below the voltage value that causes the discharge state, and if the voltage drops to a preset end-of-discharge voltage within the predetermined time, a warning of capacity reduction and life state can be issued. When the voltage reaches the terminal voltage of the discharge after a lapse of a predetermined time, it is possible to give an alarm as a simple capacity reduction.

EXAMPLES Hereinafter, the present invention will be described with reference to specific examples.

FIG. 1 is a diagram showing an example of a charging / discharging pattern during traveling. When the engine speed is low during idling or during low-speed traveling, when a vehicle-mounted load is applied and the battery is in a discharged state, It is an example showing a pattern when the load is reduced and the battery is in a charged state, and illustrates how the voltage characteristic at that time changes according to the capacity state of the battery.

The battery currently installed in the vehicle is idling. When the full load of the vehicle is applied, the amount of electricity supplied from the alternator is larger than that of the battery. It becomes a state. When the battery is normal, the time until full discharge does not cause engine trouble due to overdischarge unless heavy traffic congestion occurs as described above. However, the battery capacity decreases with the lapse of time, and the time to reach the end-of-discharge voltage gradually decreases, and the voltage may be divided within 1 to 2 minutes after entering the discharge state, and the engine may stop.

In FIG. 1, I is a battery having a normal capacity, II is a battery whose capacity is halved, and III is a characteristic close to the life. Battery I As shown in the figure, II, to discharge III end voltage (V _F), in a state that is shifted to the charging state to reduce the vehicle load, showing a state in which charging T _A 'time.

When the battery is charged for T _A time or longer, the timer that measures the discharge time is reset to T _B time. Also, when the charging time T _C = 1 / 2T _A in the charging state T _C in the figure, the timer setting time is also set to T _D ≈1 / 2T _B in proportion to the reduction of the charging state, and during discharging The voltage drop gradient of is set to be approximately constant.

When the voltage drops at a speed faster than the reference gradient and reaches the end-of-discharge voltage V _F , the capacity decrease can be displayed and the life state can be displayed at the same time. The speed of the voltage drop from the reference slope slow, displayed as a simple capacitance decreased when reaching the end voltage V _F, capacitor need only charge the display can be recovered.

V _D shown in the figure means the voltage at which the battery is discharged,
When the discharge voltage drops below this voltage, the timer measures the time.

Further, V _C means that the battery is charged when the battery voltage exceeds this voltage. Since a recent alternator has a large capacity, if a normal battery has a discharge state for 10 minutes, it will always be restored to the original capacity state by charging for 10 minutes. This is because the discharging current is 20 to 30 A, whereas the charging current is 30 to 40 A, which is shorter than the discharging time. However, the capacity of the battery at the end of its life does not recover even if it is charged for a long time, and the slope of discharge voltage drop at the time of inrush of discharge after charging is improved in a normal battery, whereas the improvement is very small.

The present invention focuses on this part, and if it is charged for a predetermined time (T _{A in the} figure), it is possible to ensure re-discharge of a normal battery up to the end-of-discharge voltage V _F for a predetermined time (T _{B in the} figure) or more. When the discharge cannot be ensured for a predetermined time or longer, it is considered to be in a life state. For example, the battery of III in FIG. 1 is T _A ′
It can be seen that even despite long been charged, a life condition has been lowered to a discharge end voltage within T _B Time. In this way, the quality of the battery can be determined by measuring the drop gradient of the discharge voltage after charging.

Although details such as voltage fluctuations and noise are not shown in Fig. 1, since the on-vehicle load is limited to about 20 ± 10A during discharge, even if voltage fluctuations occur, the voltage will be about 0.1 to 0.2V. , If the voltage difference between V _D and V _F is about 0.5 to 1.0 V, no malfunction occurs. It is data obtained by actual running with a recorder installed. In the past, it was said that the voltage during running was unstable and could not be applied to capacity judgment or life detection, but as shown in Fig. 2, the current value is Even if it fluctuates, the voltage value fluctuates only slightly.

As described above, the storage battery state detection device according to the present invention reduces the capacity by detecting the end-of-discharge voltage and the discharge voltage drop gradient that have entered the discharge state during idling / running, with simple detection software and a detection circuit. The life can be determined, and troubles due to the battery life can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a charge / discharge pattern during traveling. FIG. 2 is a diagram showing a change in voltage value when a current value changes during traveling.

Claims (1)

(57) [Claims] 1. A reversible timer is configured with this voltage as a boundary when a voltage value toward a charged state is reached or a voltage value toward a discharged state is dropped during traveling including idling, and the above-mentioned charged state is established. When the voltage above the voltage value continues for a certain period or more, the timer time can be reset so that it becomes a predetermined time corresponding to the certain period, and after the reset, the voltage value drops below the above-mentioned discharge state when the vehicle-mounted load is turned on. When the voltage drops to a preset end-of-discharge voltage within the predetermined time, a warning of capacity reduction and life status is given, and when the end-of-discharge voltage drops after the predetermined time has elapsed. Is a storage battery status detection device that can give an alarm as a mere decrease in capacity.