WO2003041240A1

WO2003041240A1 - Method and apparatus for controlling charge/discharge of lead battery

Info

Publication number: WO2003041240A1
Application number: PCT/JP2001/009755
Authority: WO
Inventors: Yasuyuki Yoshihara; Ayako Hirao; Kiichi Koike
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2000-05-30
Filing date: 2001-11-07
Publication date: 2003-05-15
Also published as: JP4566334B2; JP2001339864A

Abstract

A method and an apparatus for controlling charge/discharge of a lead battery principally used not under fully charged state but under a state where SOC is lowered, in which SOC is increased as the characteristics of the battery deteriorates due to aging.

Description

Description Charge / discharge control method and charge / discharge control device for lead-acid battery

According to the present invention, the charge / discharge control of a lead storage battery is repeated based on a state in which the capacity (state of charge (hereinafter, referred to as S0C)) is lowered instead of a fully charged state. The present invention relates to a method and an apparatus. Background art

In recent years, batteries such as electric hybrids and hybrid vehicles (Hybrid Electric Vehicle 1 e), which are being developed mainly in the automotive industry, use SOCs to fully charge the SOC even after discharging. It is proposed to use it in an intermediate area without reverting. This is to improve the energy efficiency as a whole by mainly using regenerative energy without constantly charging the battery.

Conventionally, lead-acid batteries are mostly fully charged (SOC = 100%) during use, and are mainly used for starting engines in automobiles and engines, and even when they are deeply discharged, they are charged immediately and fully charged. In any case, such as a cycle application where charge and discharge are repeated when returned, the end of charging was based on the fully charged state. This is because these charge / discharge controls have the following problems unique to lead-acid batteries.

In other words, if a lead-acid battery is used in an area where SOC is in the middle, charging becomes insufficient and inactive lead sulfate is likely to be fixed to the active material of the electrode. A drop occurs.

As a result, the actual SOC greatly deviates from the setting S0C used for charge / discharge control. As a result, batteries with lower capacities will discharge more. In addition to overdischarging and the inability to extract the required current.

The present invention solves the above-described problems, and provides a charge and discharge method and a device that can be used with high reliability over the battery life even when a lead storage battery is used in an area where S 0 C is intermediate. The purpose is to: Disclosure of the invention

In order to achieve the above object, the present invention sets the charging and discharging standard S 0C to an intermediate range in which it exceeds 0% and does not reach 100%, and sets this standard SOC to the number of charge / discharge cycles. It is characterized in that it is raised according to the following. With the above configuration, the amount of charge and discharge required for the life of the battery can be appropriately controlled, so that the life characteristics of the lead storage battery can be improved. In addition, the required amount of discharged electricity can be secured even during use of the battery. BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 is a graph showing the life characteristics of the conventional example.

Fig. 2 is a graph showing the relationship between S0C and internal resistance after the cycle elapses during the life test of the conventional example.

FIG. 3 is a graph showing the SOC adjustment pattern used in the present example, and FIG. 4 is a graph showing the life characteristics of the present invention and the conventional example. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described. First, as the lattice, an expanded lattice that cuts and expands the strip-shaped sheet material obtained by rolling the lead alloy was used. Next, as a paste containing an active material as a main component, a cathode prepared by kneading a lead oxide as a main component with water, sulfuric acid, etc. added was prepared. The negative electrode was prepared by adding additives such as lignin, water, sulfuric acid and the like to lead powder and kneading them. this These pastes were applied to the above-described expanded lattice, and were aged and dried to prepare an electrode plate.

Six electrode plates were prepared as a positive electrode and seven electrode plates were prepared as a negative electrode, and they were laminated through a glass mat, Separet, to form an electrode plate group. Six of these electrode groups were created, housed in a battery case made of synthetic resin divided into six cell chambers, and connected in series to create a 12 V, 30 Ah battery.

Using the lead-acid battery configured as described above, evaluation was performed by a charge-discharge cycle life test at an ambient temperature of 30 ° C. In this cycle life test, after discharging for 10 seconds at a constant current of 3 CA, pause for 10 seconds, perform a constant voltage charge for 30 seconds at a maximum current of 3 CA and a set voltage of 14.4 V, and then charge for 10 seconds. A total of 60 seconds during which the pause was performed was defined as one cycle. Also, since the battery has low charge acceptability in the high SOC range, it is necessary to conduct tests in a low SOC range in order to ensure a well-balanced charge with the amount of discharge. Varies by battery. Therefore, in this test, the relationship between the S0C of the test battery and the charging characteristics was examined in advance, and after setting the SOC (= 50%) to balance the charge and discharge, the cycle life test was started. Further, in a region where the SOC exceeds 80%, the regenerative charging cannot be performed efficiently, so that it is preferably 50% or more and 80% or less. Note that SOC 100% is defined as the initial 1/3 CA discharge capacity of the battery, 30 Ah.

Figure 1 shows the cycle progress of the 10th second voltage of 3CA discharge. As can be seen from this figure, the voltage characteristics dropped sharply after 10,000 cycles, and to 7 V at 17,500 cycles. Figure 2 shows the relationship between the SOC and the internal resistance of the tested batteries at the initial, 5,000, 10,000, and 15,000 cycles. The internal resistance is shown as a percentage with the initial battery S ° C 0%, that is, the internal resistance value in the fully discharged state being 100%. In addition, due to the decrease in battery capacity over the course of the test, the internal resistance of SOC 90% or less was measured at 5000 cycles, and the SOC was 80% or less at 10,000 cycles and 15000 cycles. From FIG. 2, it can be seen that the internal resistance in the region where the S 0 C is low increases extremely with the passage of the cycle. This tendency is observed even at the SOC of 50%, which is the standard for the cycle test, and is considered to correspond to the decrease in the voltage characteristics (voltage at the 10th second of 3CA discharge) after 10,000 cycles.

On the other hand, it is observed that the higher the SOC, the smaller the increase in internal resistance due to the cycling. From this, it is considered that by increasing the reference SOC with the cycle, the battery can be used in the SOC region where the internal resistance is small, and stable voltage characteristics can be secured until the end of the life.

As shown in FIG. 3, a cycle test was performed in which S0C was increased as the cycle progressed. The step-like increase in SOC over the course of the cycle shown in this figure indicates that the SOC setting can compensate for the increase in internal resistance due to battery deterioration based on the relationship between SOC and internal resistance for each cycle shown in Figure 2. Set to. If the reference SOC is increased, the charge acceptability of the battery decreases, so that the amount of charge cannot be secured with respect to the amount of discharge, and the S 0 C decreases during the cycle. By increasing the charging time during the cycle, the SOC was adjusted to secure a sufficient amount of charge. As can be seen from FIG. 4 showing the test results, the present invention suppresses the voltage characteristics from deteriorating and exhibits excellent life characteristics. In addition, the cause of battery deterioration is that in the conventional example, the temperature began to increase at 13,000 cycles and rapidly increased after 15,000 cycles, which is considered to be accelerating the battery deterioration. On the other hand, in the present invention, since the charge / discharge cycle is repeated in the S0C region where the internal resistance is small, it is considered that heat generation can be suppressed and battery deterioration can also be suppressed.

In this embodiment, the SOC setting is controlled stepwise, and the charging time is changed to increase the SOC. However, the effect of the present invention does not depend on the setting method of SOC. Industrial applicability

According to the present invention, the reference SOC for charging and discharging is set to an intermediate range in which the SOC is not more than 0% and does not reach 100%, and S0C is increased with the aging of the battery characteristics. Since the battery is used in the SOc region where the internal resistance is small, it is useful for realizing an excellent lead-acid battery that maintains stable discharge voltage characteristics and has improved life characteristics.

Claims

The scope of the claims

1. A charge / discharge control method for a lead-acid battery, wherein the reference SOC at the time of charging and discharging is set to a range exceeding 0% and not reaching 100%, and the reference SOC is increased according to the number of times of charging / discharging.

2. The charge / discharge control method for a lead storage battery according to claim 1, wherein the reference SOC is 50% or more and 80% or less.

3. Equipped with control means connected to one or more lead-acid batteries to control the charging and discharging of the lead-acid batteries based on the reference SOC set in the region that exceeds 0% and does not reach 100% of SOC A charging / discharging control device for a lead storage battery, wherein the control means discharges when S 0 C of the lead storage battery exceeds the reference S 0 C; Means for charging when the temperature is lower than 0 C; at least one of a timer and a cycle counter; and a means for changing the reference SOC based on at least one of the timer and the cycle counter. And a charge / discharge control device for a lead-acid battery.