JP4774713B2 - Storage battery overcharge prevention device - Google Patents

Description

  The present invention relates to an overcharge prevention device for a storage battery that prevents overcharge of the storage battery to prevent generation of heat and gas, breakage of an electrode plate, and the like.

  Conventionally, during the use of lead-acid batteries, electrode plates are damaged due to sulfation, gas generation, heat generation and increase in the specific gravity of the electrolyte. After that, the battery is continuously charged and charged for the same charging time as a new rechargeable battery. As a result, overcharging occurs, and the normal specific gravity 1.24 of the electrolyte rises to about 1.25 to 1.27 in the backup power supply. In the case of an electric forklift power source, the normal specific gravity 1.28 increases to about 1.32 to 1.34. According to the chemical reaction formula of a lead-acid battery, if charging is continued, lead sulfate crystals will not be formed on the electrode plate, and there is an idea that charging will be continued with less discharge, but with this On the other hand, it becomes overcharged. As an overcharge prevention device, there is a device that detects charging pressure and stops charging.

  Thus, when overcharged, hydrogen gas and oxygen gas are generated and heat is generated, which increases the risk of explosion, water evaporates, the specific gravity increases, the sulfuric acid concentration increases, the corrosion of the electrode plate is accelerated, and the life of the storage battery is increased. Was shortened. Thereby, the storage battery which should originally have a life of 10 years or more is exchanged in about five years. In order to prevent this overcharge, water management is an absolute condition, and it is almost impossible for the user to constantly monitor and prevent overcharge in the use of the storage battery, preventing overcharge and repeating charge and discharge. Therefore, it is desired to develop a device that prevents the increase in specific gravity and heat generation.

  Therefore, the present invention provides an overcharge prevention device capable of preventing the overcharge at the time of charging and preventing the damage and deterioration of the electrode plate of the storage battery by extending the specific gravity value of the storage battery and extending the life of the storage battery. The purpose is to do.

  The storage battery overcharge prevention device of the present invention includes an overcharge detection sensor for detecting overcharge of the storage battery, and a discharge circuit for operating the signal from the overcharge detection sensor to discharge the current in the storage battery. It is characterized by comprising.

  The overcharge detection sensor may include at least one of a voltage detector that detects a voltage in the storage battery, a temperature sensor that detects the temperature of the storage battery, and a specific gravity sensor that detects the specific gravity of the electrolyte. .

  The overcharge prevention circuit may be connected to a charging device for charging the storage battery and a sulfation removal device for removing sulfation generated at the electrode of the storage battery.

  Furthermore, you may perform the operation | movement of the said sulfation removal apparatus with the electric power from the storage battery attached to them.

  According to the present invention, when the overcharge sensor detects the overcharge of the storage battery, the discharge circuit operates to prevent overcharge, thereby suppressing the heat generation of the storage battery, and the specific gravity of the electrolyte keeps the reference value. The deterioration and damage of the electrode plate can be prevented, and the life of the lead storage battery can be extended.

  The overcharge detection sensor may be a voltage detector, a temperature sensor, or a specific gravity sensor.

  Moreover, if a sulfation removal device is attached to the discharge circuit, the life of the lead-acid battery can be further extended. If the power supply of the sulfation removal apparatus is the storage battery itself, it is not necessary to provide a separate power supply, and the entire apparatus can be made compact.

  The best mode for carrying out the invention will be described below with reference to the drawings.

  In FIG. 1, a lead storage battery M has a rectangular casing 1, and a positive electrode 3 and a negative electrode 4 are provided at one corner of the upper surface 2, and the electric power of the storage battery can be taken out from these two electrodes. Along with this, a discharge circuit 5 is connected to both electrodes. The discharge circuit 5 has a discharge lamp 6 that acts as a resistance for discharge. Further, a charger 7 is connected to the discharge circuit 5, the charger 7 is controlled by a controller 8, and the controller 8 is operated by a battery 9. The discharge circuit 5 includes a switch 10, which is opened and closed by a signal from an overcharge detection sensor, which will be described later. A switch 11 is provided in the charging circuit of the charger 7, and the switch 11 is connected to the controller 8. It opens and closes by a signal from.

On the other hand, a sulfation removal device 12 is connected to the discharge circuit 5, and this sulfation removal device 12 is a device disclosed in Japanese Patent Application No. 2003-181057 filed earlier by the present applicant, and is shown in FIG. A negative pulse having a large depth and a narrow width (Eneg, Tneg) is generated, and lead sulfate (PbS0 ₄ ) is removed from the electrode plate by melting (molecular decomposition). The sulfation removal device 12 is connected to the electrodes 3 and 4 of the lead storage battery M and operates using the lead storage battery M as a power source. This sulfation removal device 12 prevents the surface area of the lead electrode plate from decreasing and maintains its porosity. The generated pulse may be a positive pulse as shown in FIG. The frequency of the pulse is preferably 1500-12000 (the same applies to the pulse in FIG. 2).

  On the other hand, the lead storage battery M is provided with a temperature sensor 20 for detecting the temperature of the electrolytic solution or a specific gravity center 21 for detecting the specific gravity of the electrolytic solution when it is an open type. When the lead storage battery M is a sealed type, the temperature sensor 22 may be attached to the side wall of the casing 1. A voltage sensor 30 is provided between the electrodes 3 and 4, and the temperature sensors 20 and 22, the specific gravity sensor 21 and the voltage sensor 30 are overcharge detection sensors for detecting the overcharged state of the lead storage battery M. I am doing. And the signal of these overcharge detection sensors 20, 21, 22, and 30 is input into the controller 25, and the controller 25 opens and closes the switch 10 by the signal from an overcharge detection sensor.

When the lead storage battery M is overcharged, the temperature rises to a predetermined value or more (temperature 32 ° C. or more), and the specific gravity of the electrolyte also increases, so these values are determined according to the atmospheric temperature and the storage battery voltage. It is set to a predetermined value and an overcharge signal is issued when each sensor exceeds a predetermined value.

  Now, when the voltage of the lead storage battery M decreases and charging is necessary, the controller 8 turns on the switch 11 and simultaneously operates the charger 7. At this time, the switch 10 is OFF and the discharge circuit 5 is not operating. When the temperature sensor 20, the specific gravity sensor 21, the temperature sensor 22 or the voltage sensor 30 detects a predetermined value indicating overcharge, the controller 25 turns on the switch 10, turns off the switch 11, and turns off the charger 7. . As a result, the discharge circuit 5 operates and the discharge lamp 6 is lit. When the discharge circuit 5 is discharged, and the values of the sensors 20, 21, 22, and 30 become a predetermined value or less, the controller 25 turns off the switch 10 to stop the discharge.

  The sulfation removal device 12 is turned off at the time of discharging by a signal from the controller 25, and starts operating again when the discharging is completed.

  In general, the relationship between the specific gravity of the electrolyte and the state of charge is shown in Table 1 (in the case of new electrolyte specific gravity 1.28), Table 2 (in the case of new electrolyte specific gravity 1.26) and Table 3 (when the liquid temperature is 20 ° C.). (In the case of a new electrolyte specific gravity of 1.24), it corresponds (the specific gravity increases when the state of charge increases), and the storage battery M is preferably maintained at an outside air temperature of 20 ° C.

すなわち、一般に、電解液の温度が上昇すると比重は低下し、一般の鉛蓄電池の新品時の比重は、液温２０℃を基準に１．２８００であり、比重の変化の割合は１℃で０．０００７であり、したがって、例えば、液温が４０℃の場合には、
４０℃−２０℃＝２０℃
２０℃×０．０００７＝０．０１４
１．２８００−０．０１４＝１．２６６０
となる。

That is, in general, when the temperature of the electrolytic solution rises, the specific gravity decreases, the specific gravity of a general lead-acid battery when new is 1.2800 based on the liquid temperature of 20 ° C., and the change rate of the specific gravity is 0 at 1 ° C. Therefore, for example, when the liquid temperature is 40 ° C.,
40 ° C-20 ° C = 20 ° C
20 ° C. × 0.0007 = 0.014
1.2800−0.014 = 1.2660
It becomes.

  Therefore, the liquid temperature is detected by the temperature sensor 20, the specific gravity in the fully charged state (100%) corresponding to this liquid temperature is obtained, and when the specific gravity sensor 21 detects a specific gravity higher than this value, the controller 25 detects the discharge signal. To emit. Even if the voltage sensor 30 detects a value greater than or equal to a predetermined value, it is overcharged, so the controller 25 also issues a discharge signal at this time. Since the temperature correction is not required when the lead storage battery M is maintained at 20 ° C., the specific gravity sensor 21 can operate alone.

  The present applicant attached the above-mentioned overcharge prevention device M and the sulfation removal device 12 to a backup lead-acid battery (electric capacity: 108 V, 500 A), discharged a 10 A current for 3 hours, and observed it for about 9 months.

  At the start of the experiment, there was heat generation at an average specific gravity of 1.27 and a liquid temperature of 32 ° C., and there was water evaporation. It was seen.

  Furthermore, the device was mounted on a lead-acid battery for an electric forklift and tested for about two months. Overcharge was prevented, but when the device was not installed, an obvious overcharge state was detected.

  The overcharge prevention device of the present invention can be used for various lead batteries. Specific examples include backup power supplies for hospitals, banks, communication facilities, buildings, hotels, etc., electric forklifts, electric cars, electric vehicles, buses, motorcycles, golf carts, emergency radios for electric vehicles, solar power generation, wind power generation, etc. It can be used for lead-acid batteries.

  Furthermore, the overcharge prevention device of the present invention can be used for overcharging of storage batteries other than lead storage batteries (nickel metal hydride storage batteries, lithium ion storage batteries, etc.).

FIG. 1 is a schematic configuration diagram of a storage battery overcharge prevention device of the present invention. FIG. 2 is a pulse waveform diagram generated from the sulfation removal apparatus. FIG. 3 is another pulse waveform diagram generated from the sulfation removal apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Casing 5 ... Discharge circuit 7 ... Charger 8 ... Controller 20, 22 ... Temperature sensor
21 ... Specific gravity sensor

Claims (4)

In order to detect the overcharge of the storage battery, a temperature sensor that detects the temperature of the electrolyte of the storage battery and a specific gravity sensor that detects the specific gravity of the electrolyte are provided, and a new electrolyte specific gravity at the time of full charge at the reference temperature is measured in advance. Then, find the difference between the actual electrolyte temperature and the reference temperature, perform temperature correction to determine the electrolyte specific gravity value when the actual electrolyte is fully charged, and discharge when the specific gravity sensor detects a value higher than that. An overcharge prevention device for a storage battery characterized by operating a circuit.   2. The overcharge prevention device for a storage battery according to claim 1, wherein the temperature correction is calculated on the assumption that the specific gravity change rate of the electrolyte is 0.0007 at 1 ° C., and the specific gravity decreases as the temperature increases. .   3. The overcharge prevention according to claim 1, wherein a charging device for charging the storage battery and a sulfation removal device for removing sulfation generated at the electrode of the storage battery are connected to the overcharge prevention circuit. apparatus.   The overcharge prevention device according to any one of claims 1 to 3, wherein the operation of the sulfation removal device is performed by electric power from a storage battery to which they are attached.

Images