JPH07230828A - Charging method for lead-acid battery - Google Patents

Abstract

PURPOSE:To detect a trickle life of a battery preliminarily by separating a number of serially connected lead-acid batteries in two blocks or more and N/3 blocks or less, and measuring voltage fluctuation of each block at the time of starting charging or' discharging. CONSTITUTION:In the case of a non-power failure power source device comprising 24 serially connected mono-block batteries, for example, in which constant voltage charging is performed, the 24 batteries are separated into three blocks of 8, and a battery voltage is measured for each block. Voltage fluctuation per unit time at the time of charging is expressed by dVc/dt=d(IDXnXR0)/dt. This fluctuation width is measured for each block, and when it exceeds a fluctuation width preliminarily determined for the sort of the battery, a serial number, etc., a display of life of the battery is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead-acid battery for charging a power source such as an uninterruptible power supply (UPS), and more particularly to a trickle charging method.

[0002]

2. Description of the Related Art Lead acid batteries are often used in series when they are used as a power source for UPS and the like, and many single cells or monoblock batteries are used in series. It affected the trickle life of the battery. For this reason, the charging voltage is set to have a temperature gradient depending on the ambient temperature, and the charging method called uniform charging has been devised so that the battery is uniformly charged.

[0003]

However, when a large number of conventional monoblock batteries are connected in series, it is usually 2
At 5 ° C, the battery is used with constant voltage charging at a charging voltage of 2.3 V / cell, but when multiple batteries are connected in series, the voltage variation between the batteries affects the trickle life of the batteries. Was being given.

When constant voltage charging is performed, it is possible to extend the trickle life of the batteries by reducing the variation of the charging voltage between the monoblock batteries, and to reduce the variation of the life of N batteries. . But usually N
When individual batteries are used in series connection, there is a problem that the variation in charging voltage between cells increases, and the variation increases as the number of series increases. Therefore, there is a problem that the trickle life of the battery varies from battery to battery, and the life becomes short in the unit of the number of series.

The present invention solves the above-mentioned conventional problems, and when using a battery as a power source in multiple series such as UPS,
The trickle of the power supply battery is extended, and at the same time, the life of the battery is estimated.

[0006]

In order to solve the above problems, the present invention provides a charging method in which N batteries are connected in series, and N batteries are divided into sections of 2 blocks or more and N / 3 blocks or less. By measuring the voltage fluctuation range of the battery voltage between each block at the time of charging or discharging, it is understood that the discharging time becomes longer when the fluctuation range becomes larger than the predetermined value. Then, a maintenance request or battery replacement is displayed on a device such as UPS.

The greatest cause of the deterioration mode of the battery used for trickle charging is that the internal resistance of the battery increases due to the decrease in the electrolytic solution. By detecting the internal resistance of the battery as the above-mentioned voltage fluctuation range, the battery It is possible to estimate the life deterioration state of the.

By adding these functions to a device such as a battery or UPS, a U used in an emergency such as a power outage
This is to prevent a system such as a PS from going down due to a power supply battery and being unable to back up a computer.

[0009]

[Operation] By adding the above function to the power battery,
The reliability of UPS used for backup of computers and the like at the end of battery life is improved and system down of the computer system is prevented.

[0010]

EXAMPLES Examples of the present invention will be described below with nominal 12V, 1.V.
An example of UPS in which 24 3 AH monoblock batteries are connected in series and constant voltage charging with a maximum current of 0.26 A and a charging voltage of 217.6 V is performed will be described as an example.

The 24 batteries were divided into 3 blocks of 8 cells so that the battery voltage could be measured for each block.

The voltage fluctuation per unit time during charging is represented by dV _C / dt = d (I _C × n × R _O ) / dt. Here, I _C is the discharge current, n is the coefficient, and R _O is the initial internal resistance of the battery. On the other hand, the voltage fluctuation per unit time at the time of discharging is represented by dV _D / dt = d (I _D × n × R _O ) / dt. These fluctuation widths are measured for each block, and when the fluctuation width exceeds a predetermined fluctuation width according to the battery type, the number of series, etc., the battery life is displayed.

In the case of the embodiment, when dt = 3 seconds, the voltage fluctuation during charging becomes larger as the trickle usage period of the battery becomes longer as shown in FIG. 1, and the dispersion of the battery becomes larger. it is obvious.

At the time of discharge, the voltage fluctuation when the discharge load is constant can be obtained as in FIG. This has an ambient temperature of 30
Although the results are in ° C., when the ambient temperature changes, it is clear that the present embodiment functions in the same manner by adding a temperature gradient to the voltage fluctuation range. Further, FIG. 2 shows an example of voltage change at the time of starting discharging and charging.

When the number of batteries connected in series is large, dV / d
Although the variation of t becomes large, by dividing the number of series into two blocks or more and N / 3 blocks or less, dV /
It is possible to reduce the variation of dt and improve the reliability of battery life prediction.

These fluctuation ranges can be obtained in advance from the type of battery, charging current and discharging load, stored in UPS or the like as an internal memory, and collated as necessary to predict the battery life. . This flow is shown in FIG.

[0017]

As described above, according to the present invention, it is possible to detect the life of a battery used for an emergency power source such as UPS in advance, and it is extremely effective in securing the reliability of the system. large.

[Brief description of drawings]

FIG. 1 is a relationship diagram between dV _C / dt during charging and trickle usage period according to the present invention.

FIG. 2 is a diagram showing a relationship between time at the time of starting discharging and charging and voltage change

FIG. 3 is a diagram showing a flow of battery life prediction.

[Explanation of symbols]

 Z Width defined in Fig. 1 B Set value of maximum deviation between blocks

Claims (4)

[Claims] 1. A single cell or monoblock lead-acid battery
In a charging method of connecting (N ≧ 4) pieces in series,
A method of charging a lead storage battery in which each battery is divided into two blocks or more and N / 3 blocks or less, and a voltage fluctuation is measured for each block to estimate the discharge time of the battery. 2. The charging method for a lead storage battery according to claim 1, wherein the voltage fluctuation is measured as a voltage fluctuation width per unit time at the start of charging. 3. The method of charging a lead storage battery according to claim 1, wherein the voltage fluctuation is measured as a voltage fluctuation width per unit time at the start of discharge. 4. The lead-acid battery according to claim 1, wherein the battery voltage for each block is measured, and the discharge time of the battery is estimated by adding a temperature gradient to the voltage fluctuation width per unit time at the start of charging or at the start of discharging. How to charge.