JPH01318979A - Deterioration warning apparatus for storage battery - Google Patents

Abstract

PURPOSE:To detect deterioration of a battery accurately by comparing an initial operable time and a present operable time in a charge/discharge cycle of a storage battery, and detecting whether the battery discharge capability is decreased to a preset ratio of decrease in a limit operating time or not. CONSTITUTION:A CPU 16 detects the completion of charging in a storage battery 11. The accumulated operating time from the start of discharge after the completion of charging to a time when the terminal voltage of the battery drops to a specified voltage is stored. At the same time, the value of the storage battery at the initial period of use for the accumulated operating time is stored. Then, the CPU 16 obtains the ratio between the accumulated operating time at present and the accumulated operating time at the initial period of use of said storage battery. When said ratio is decreased to the value lower than a specified ratio, it is judged that the battery is deteriorated and a warning output contact 22s is turned ON. In place of the accumulated operating time from the start of discharge to the time when the terminal voltage of the battery drops to the specified voltage, an accumulated quantity of used electricity is stored. The time when the ratio between the accumulated quantity of the electricity at present and that at the initial period of battery used becomes lower than the specified ratio is detected, and warning of the deterioration of the battery is issued.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a deterioration warning device used in storage batteries for electric vehicles, etc., which warns of deterioration of the storage battery.

``Conventional technology'' Conventionally, the decision to replace storage batteries used in electric vehicles has been made each time by a driving manager based on the decrease in available driving time and the number of years of use. As an aid to this, a driving time meter, charge/discharge count hand, etc. may be installed, but actual operating time, load amount, discharge depth, charging status, etc.
Since it varies considerably depending on the application and installation environment, the battery life curve also differs, and it is difficult to estimate the battery life from only the operating time meter or charge/discharge count hand.
It was difficult to determine when to replace the storage battery when the battery capacity had been fully exploited. Determining when to replace storage batteries, which account for a large proportion of the price of an electric vehicle, is one of the important management items for users, and there has been a desire for a storage battery deterioration detection system that solves the above-mentioned problem.

``Problems to be Solved by the Invention'' An object of the present invention is to provide a storage battery deterioration warning device that displays and warns the appropriate time to replace the storage battery.

"Means for Solving the Problems" According to the present invention, the completion of charging of a storage battery is detected, and the cumulative operating time from the start of discharging after the completion of charging until the battery terminal voltage drops to a specified voltage is stored. The value of the cumulative operating time at the initial stage of use of the storage battery is stored, and a warning is issued as battery deterioration when the ratio of the cumulative operating time between the current time and the initial stage of battery usage falls below a certain ratio.

In addition, instead of the cumulative operating time from the start of discharge until the battery terminal voltage drops to the specified voltage, the cumulative amount of electricity used is stored, and when the ratio of the cumulative amount of electricity used between the current time and the initial period of battery use falls below a certain ratio. issues a warning as the battery is deteriorating.

``Function'' Figure 1 shows the discharge characteristics of lead-acid batteries, which are mainly used as storage batteries for electric vehicles. As shown in the figure, in a standard charge/discharge cycle, the battery capacity increases once and then gradually decreases. Therefore, in the charge/discharge cycle of a storage battery, compare the initial available operating time and the current available operating time. The limit operating time reduction ratio (0,8
~0.5), when the storage battery discharge capacity drops to 0.5), a warning is issued indicating that the battery is deteriorating. Discharging time is measured as the time required for the battery voltage to drop to a preset voltage, and data is captured only after charging is complete or equal charging is completed to prevent misjudgments when charging is interrupted.

Embodiment FIG. 2 shows an embodiment of the present invention, in which a storage battery 11 is connected to a load 13 through a load switch 12.

The terminal voltage of the M battery 11 is supplied to the AD converter 15 through the voltage dividing circuit 14, and the output of the AD converter 15 is input to the CPU 16 which performs deterioration determination. The terminal voltage of the storage battery 11 is supplied to the constant voltage circuit 17, and from the constant voltage circuit 17 the CPU
16 and the driving circuit 18 are supplied with operating voltages. The backup capacitor 19 is provided to protect the initial charge/discharge data against extreme voltage drops. CPU1
The output of 6 is the driving circuit 18 for the indicator light 21 and alarm relay 22.
Drive through. As shown in FIG. 3, the display panel shows the voltage of the storage battery 11 through indicator lights p,,p,! The indicator light pH is displayed when the storage battery is in good condition, the indicator light pz is displayed when the battery is in a deterioration warning state, and the indicator light pu is displayed when the storage battery is in a deteriorated state.
s is displayed.

As shown in FIG. 4, the CPU 16 has areas in the RAM for a cumulative timer memory, an initial discharge cumulative memory (CI), a current discharge cumulative memory (Cn), a measurement number memory (n), and a charge completion flag memory.

An example of the operation of the CPU 16 is shown in FIG. By initial setting (S+), the cumulative timer memory and counting number memory n are cleared to 0. Cumulative memo'J-C1,Cn
The standard operable time is set as an initial value.

Next, the AD converter 15 reads the battery voltage VB (step S).

At branch S3, battery voltage value VB is equal to charging completion voltage VH.
2, and if it is larger, it is determined that charging is complete, and a charging completion flag is set to H (S4).

If it is smaller, proceed to branch S.

At branch S, the voltage is slightly higher than the battery open circuit voltage (about IV).
When the battery voltage is high, it is determined that charging is in progress, and the discharge time cumulative timer value and charging completion flag are cleared (S,).

If it is low, nothing is done and the process proceeds to the display routine (S,).

In the display routine S, the voltage indicator lamps (p, .about.PI) shown in the upper row of FIG. 3 are turned on according to the battery voltage to display the current voltage.

At branch S8, the charging completion flag is checked, and if it is, the process returns to VB reading. If the flag is H, it is determined that charging has been completed, and the process proceeds to branch S to start measuring the discharging time.

At branch S, the battery voltage is compared with the set voltage VLI, which is slightly lower than the battery open special voltage (about 1V), and if it is lower, it is determined that it is discharging, and the discharge time cumulative timer is turned on (S+). If the timer is high, the timer is determined to be stopped (S++).

At branch S1□, the battery voltage VB is compared with the battery voltage VL2 set at the overdischarge prevention level, and if it is higher, the process returns to reading VB. If it is low, the over-discharge indicator light is turned on and the charge completion flag is reset (sti).

Subsequently, the measurement count memory is incremented by 1 (S14).

At branch srs, it is determined whether the number of measurements is the first time, and if it is the first time, the cumulative timer value is stored in the 01 memory (S16);
If it is not the first time, store it in the Cn memory (S,...), and clear the cumulative timer memory (S+a). Next, calculate the ratio of the initial discharge value to the current discharge value = Cn/C1 (S
19).

At branch S2°, it is determined whether k fJ < 0.5 or less,
If it is 0.5 or less, the degraded light pts is turned on (Sz+
), the alarm relay 22 is further driven, and its contact output becomes O.
It is set to N (Szg) and returns to VB reading. Branch 5
If k is 0.5 or more at t11, proceed to branch Szs, and if k is 0.7 or less, deterioration warning light P14 is turned ON (St
4) Return to VB loading. If k is 0.7 or more, the good light P13 is turned on (Szs) and the process returns to VB reading.

In the above description, the cumulative total of discharge time was measured, but the cumulative total of the amount of electricity used may also be measured. That is, as shown in FIG. 6, for example, the load current of the storage battery 11 is shunted by the shunt 23, its output is amplified by the DC amplifier 24 and converted into a voltage value, and the output is supplied to the AD converter 15. , the amount of electricity used is read into the CPU 16, the amount of electricity used during discharging is cumulatively calculated, the ratio k of the cumulative amount of electricity used between the current time and the initial period of battery use is determined, and it is detected whether this is below a certain value. You can. In this case, step S2 in FIG.
When reading VB, the amount of electricity is also read, and this amount of electricity is accumulated by an accumulation timer.

In short, in this invention, as shown in Fig. 7, the operating time or discharge amount when the battery is fully charged and then discharged to the overdischarge level is measured as C+, Cz..., and the value C at the initial stage of battery use is determined.
against 1. The ratio k to the current value Cn is determined, and when this k becomes a predetermined value or less, it is determined that the storage battery has deteriorated.

In addition, the first measurement amount C1 and the current measurement amount Cn are stored in the memory.
Cn/C1 was calculated by memorizing the following, but C, l+ C1
1-1+ CM-1"' Ca-a-1 is stored in the memory up to the measurement amount m times before, and its moving average 07'=(Cn
10Ca-+ +C++-g+..." Cn-1
1-1) Find / m, and the standard value is also the average C+ of m@
' = (C+ 10, +・+C11) /m can be calculated and CJ/C1' can be calculated to reduce the influence of variations due to changes in operating conditions.

"Effects of the Invention" According to the present invention, battery deterioration is determined and displayed when the ratio of the initial operating time of the electric vehicle to the current operating time after equal charging falls to a certain level. A battery deterioration warning device that can use batteries can be provided.

Furthermore, even if the capacity of the battery used changes, it has a learning function that automatically sets the initial capacity of the storage battery by measuring the initial cumulative operating time, so it can be installed regardless of the model. Furthermore, by performing the determination operation only after equal charging, it is possible to avoid false alarms in a recoverable battery capacity reduction mode, such as when charging is uneven between cells of a storage battery or when charging is insufficient.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the discharge characteristics of a storage battery, FIG. 2 is a diagram showing an embodiment of the present invention, and FIG. 3 is a diagram showing an example of a display panel.
Fig. 4 is a diagram showing the storage area of the RAM, Fig. 5 is a flowchart showing an example of the operation of the inventive device, Fig. 6 is a diagram showing another example of the invention, and Fig. 7 is a diagram showing charging and discharging of the storage battery. It is. Patent applicant: Sanyo Electric Manufacturing Co., Ltd.

Claims (2)

[Claims] (1) A means for detecting the end of charge of the storage battery, a means for storing the cumulative operating time from the start of discharging after the end of charging until the battery terminal voltage drops to the specified voltage, and a value of the cumulative operating time at the initial stage of use of the storage battery. A deterioration warning device for a storage battery, comprising: means for storing: and means for warning that the battery has deteriorated when the ratio of the cumulative operating time between the current time and the initial period of use of the battery falls below a certain ratio. (2) means for detecting the end of charge of the storage battery; means for storing the cumulative amount of electricity used from the start of discharging after the end of charging until the battery terminal voltage drops to a specified voltage; and the cumulative amount of electricity used during the initial period of use of the storage battery. A deterioration warning device for a storage battery, comprising means for storing a value of the battery, and means for warning that the battery has deteriorated when the ratio of the cumulative amount of electricity used between the current time and the initial period of use of the battery falls below a certain ratio.