JPH01217280A - Method for detecting deterioration state of storage battery - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a method for detecting the state of deterioration of a storage battery.

Conventional technology Conventionally, detection and detection of abnormal conditions for vehicles, especially automotive lead-acid batteries,
There are many ideas regarding display. Most of these use the discharge current and discharge voltage at the time of starting to determine the remaining capacity of the storage battery and the quality of the engine.

Furthermore, a method has also been proposed in which the storage battery is discharged for a short period of time by keeping the discharge current substantially constant.

Problems to be Solved by the Invention Automotive lead-acid batteries are installed for the purpose of starting the engine and supplying power to on-vehicle equipment.

When a lead-acid battery deteriorates to a certain extent, its ability to supply electricity to the starter that starts the engine decreases, and eventually the starter becomes unable to rotate. The inability to start the engine due to lead acid battery deterioration is fatal to drivers, and it would be extremely beneficial to easily obtain information about the deterioration state in advance.

Conventionally proposed devices discharge or charge a storage battery, detect the battery voltage at that time, perform various conversions, and detect the deterioration state of the lead storage battery. That is, the deterioration state of the lead-acid battery is detected by keeping it in a dynamic state. Therefore, the device itself is expensive and often has low reliability.

Means for Solving the Problems The present invention detects the deterioration state of a storage battery using the battery voltage when the storage battery is in a static state, that is, when the circuit including the storage battery is in an OFF state in which no current flows.

Means to solve the problem A storage battery deteriorates and becomes unable to start the engine due to the following reasons: the state of charge decreases or the output (especially the discharge voltage)
This is the case when the value decreases.

1. The current collector of the electrode plate corrodes, reducing conductivity and reducing charging efficiency.

2. The active material of the electrode plate deteriorates, reducing charging efficiency.

3 When the amount of discharge is greater than the amount of charge and the state falls into a discharge state. , 4. At the end of a battery's life, a minute short circuit occurs inside the battery, reducing charging efficiency and increasing self-discharge.

The present invention focuses on the fact that cases 1 to 4 above result in a decrease in the specific gravity of the electrolyte, and further focuses on the fact that in case 4, the self-discharge current increases and the rate of decrease in battery voltage is high. It is used to detect the end of life of a product.

EXAMPLE The case of a 34B19 type, which is a general lead-acid battery for automobiles, will be shown below. Fig. 3 shows the discharge state and open circuit voltage (after 15 hours) of the storage battery with different battery usage periods. The discharge state in Figure 3 means that the battery is left unattended for 15 hours after getting off the vehicle (at 25°C).
), then measure the open circuit voltage, and then at a current of 5.4A,
Discharge for 1 hour. This corresponds to 20% of the nominal capacity.

The battery was left for another 15 hours, the open circuit voltage was measured, and the battery was discharged at 5.4 A for 1 hour.

This operation changes the discharge state. If you repeat this operation, the terminal voltage (10, 2
V, below which it becomes difficult to continue discharging), so the discharge did not continue. The one that was installed in the car for 6 months was able to discharge up to 80%. In FIG. 3, the discharge state and open circuit voltage show good linearity.

This is because the electromotive force decreased because the specific gravity decreased due to discharge. The longer the vehicle has been in use, the lower the open circuit voltage will be.

FIG. 4 shows the time course of the open circuit voltage after each battery was charged to 125% of its discharge amount. Differences in the rate of drop in open circuit voltage can be observed for up to about 4 hours.

This difference is due to the difference (more or less) in the self-discharge amount of each battery. The reason why self-discharge increases as the period of on-vehicle use increases is that S6 and Cu eluted from the anode lattice during charging and discharging adhere to the active material, thereby generating and accelerating local batteries. Moreover, if a short circuit occurs inside the battery, self-discharge is further accelerated.

The one that has been in the car for 2.5 years has an internal short circuit in one cell.

FIG. 5 shows the startability in each discharge state. The critical discharge state changes depending on the period of use in the vehicle. This is due to the decrease in the capacity of each battery itself, but referring to FIG. 3, it is shown that starting performance deteriorates when the open circuit voltage drops below 12.5V.

Figure 6 shows the key switch of today's cars.

The key is inserted in the 0 position (locked) in the diagram and rotated to the 1 position (OFF, engine stop) and the 2 position (A
CC, accessor IJ-), position 3 (ON, this position while driving), then start the engine at 4 (start).
Return to position. When the driver stops the engine, removes the key, and leaves the car, the driver should move from position 3 to 2.1.
Unscrew the O key. The flowchart in FIG. 1 shows the procedure performed using the driver's key removal/attachment operation. Figure 2 simply shows the relationship between the circuit configuration of the automobile's electrical system and the key switch.

The first step is when the key passes the off position (1 in FIG. 6) and the measurement begins.

In the second step, the battery voltage, which is the standard for determining the lifespan, is measured. In the third step, the battery voltage is measured every hour starting from the beginning of the hour, and in the fourth step, the difference from the second step is calculated, judged, and stored. 5th step (key is reinserted and
When the determination 1 is No (when the battery reaches the position ce), that is, when the battery voltage is equal to or higher than a predetermined value, "life" is displayed. At this time, the battery voltage is measured as a sixth step, and judgment 2 is made.
When is NO, that is, when the battery voltage is below a predetermined value,
"Charging required" is displayed. In the seventh step, the measured value is erased and one detection operation is completed. Using this method, we randomly selected cars and examined the evidence. For each battery, the displayed contents and the battery performance at that time are shown in Table 1.

Table 1: Batteries that are marked as confirmatory are nearing their limit, which clearly reflects their deterioration status. By changing the determination numbers shown in FIG. 1, it is possible to adapt to the size of the battery and the type of use.

Effects of the Invention According to the present invention, the deterioration state of the storage battery can be detected during the period of rest, and countermeasures can be prepared before the next operation.

[Brief explanation of the drawing]

Fig. 1 is a flowchart showing an embodiment of the present invention; Fig. 2 is a main circuit and sub-circuit including an automobile key switch and a storage battery; Fig. 3 is a correlation diagram between the discharge state of the in-vehicle storage battery and the open circuit voltage; Figure 4 is a graph showing the change over time in the open circuit voltage after charging of the vehicle storage battery, Figure 5 is a correlation diagram between the discharge state of the vehicle storage battery and startability, and Figure 6 is an explanatory diagram showing an example of an automobile key switch.

Claims (1)

[Claims] The battery voltage is detected immediately when the main circuit including the storage battery is turned off, and the difference between this battery voltage and the battery voltage detected at predetermined intervals thereafter and the battery voltage detected immediately when the main circuit is connected again are used to detect battery deterioration. A method for detecting a deterioration state of a lead-acid battery, characterized by displaying states in correspondence.