JPH0351890Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lead-acid battery incorporating a gas generator to reduce the concentration gradient between the top and bottom of the electrolyte.

When a lead-acid battery discharges, dilute sulfuric acid, which is an electrolytic solution, is consumed, and the positive and negative electrode active materials each change to lead sulfate, and as a result, the specific gravity of the electrolytic solution decreases. on the other hand,
During charging, sulfuric acid is released from the lead sulfate of the electrode plate, and the specific gravity of the electrolyte gradually increases, and when the battery reaches a fully charged state, it returns to the specific gravity before discharge. The manner in which the specific gravity of the electrolyte increases during charging is related to gas generation from the electrode plates. Because the sulfuric acid released from the positive and negative electrode plates has a high specific gravity, it flows downward along the electrode plate surface and accumulates at the bottom of the battery, and is difficult to mix evenly, resulting in a large concentration between the top and bottom of the electrolyte. A gradient occurs. This concentration gradient is eliminated because gas bubbles generated during overcharging are stirred as they rise in the electrolyte. If a lead-acid battery is used with a concentration gradient between the top and bottom of the electrolyte, the discharge capacity will decrease and the electrode plates will deteriorate early, resulting in a shortened lifespan. The method of use resulted in considerable overcharging. For this reason, the positive electrode grid was severely corroded, making it impossible to significantly improve the life.

The present invention eliminates the above-mentioned drawbacks and provides a lead-acid battery with a small amount of overcharging, that is, a small concentration difference between the electrolyte top and bottom even when used without much gas generation during charging. be.

That is, the present invention has an electrolyte inlet near the bottom end of a cylindrical body made of acid-resistant, electrically insulating material such as plastic or glass, and an electrolyte discharge port near the top end of the cylindrical body. , respectively, and a gas generating device equipped with a rod-shaped or wire-shaped lead alloy gas generating electrode inside the cylindrical body is disposed in the electrolytic solution, and the gas generating electrode of the gas generating device is connected to the negative electrode side. The present invention provides a lead-acid battery made of

Hereinafter, the present invention will be explained in detail using the drawings.

The figure is a schematic configuration diagram showing one embodiment of the lead-acid battery of the present invention, in which 1 is the lead-acid battery according to the present invention, 2 is a positive electrode plate, 3 is a negative electrode plate, 4 is a separator, 5 is an electrolyte,
(dilute sulfuric acid). 6 indicates a positive terminal, and 7 indicates a negative terminal. Reference numeral 8 denotes a gas generator having a cylindrical body 10 made of an acid-resistant, electrically insulating material such as plastic or glass, and the gas generator 8 has an inlet 11 near its lower end for sucking an electrolyte.
It has a structure in which a rod-shaped or wire-shaped lead alloy gas generating electrode 9 is mounted inside a cylindrical body 10 having a discharge port 12 near its upper end for discharging an electrolyte. Reference numeral 13 denotes a sealant having acid resistance and electrical insulation properties, such as epoxy resin, for fixing the gas generating electrode 9 inside the cylindrical body 10. 14 is a lead wire connecting the gas generating electrode 9 and the negative electrode terminal 7, 15 is a battery exhaust plug, and 16 is a hydrogen gas bubble.

Next, to explain the operation of this embodiment, when charging the storage battery, the gas generating electrode 9 is connected to the negative electrode terminal 7, so its potential is almost the same as that of the negative electrode plate 3, and as the charging progresses, the potential gradually decreases. As the temperature decreases, hydrogen gas bubbles 16 begin to be generated from the gas generating electrode 9. Theoretically, hydrogen generation begins when the voltage at which electrolysis of water occurs (theoretical decomposition voltage 1.23V) is exceeded, but in the case of a lead electrode, the hydrogen overvoltage is extremely large, so even at the open circuit voltage of a lead-acid battery. It almost never happens. However, in reality, due to charging, the potential of the negative electrode plate, that is, the potential of the lead alloy gas generating electrode 9 connected to it, increases by 0.2 to 0.3 V further than the open circuit potential.
When polarized to the base, hydrogen gas bubbles begin to be generated from the surface of the gas generating electrode 9. During normal charging, if the terminal voltage of the lead-acid battery exceeds approximately 2.4V, the gas generating electrode 9
Gas generation due to water decomposition on the surface becomes significant.
The hydrogen gas bubbles 16 rise within the cylindrical body 10, and as the gas bubbles 16 flow upward at this time, the electrolyte also moves together, causing an upward flow. Further, when the hydrogen gas bubbles 16 generated from the gas generating electrode 9 rise inside the cylindrical body 10, the small bubbles gradually gather to form a large bubble, and when this bubble fills the inside of the cylindrical body 10 and rises, The electrolyte 5 is sucked upward by the pump action. In this way, in the lead-acid battery 1 according to the present invention, during charging, the electrolyte having a high specific gravity is absorbed into the cylindrical body 10 through the suction port 11 at the lower end of the gas generator 8, and the electrolyte solution having a high specific gravity is absorbed into the cylindrical body 10 through the discharge port 12 at the upper end.
Since the electrolyte is circulated by being released together with hydrogen gas, the upper part of the electrolyte 5 in the battery is
It is possible to eliminate the difference in specific gravity between the lower parts. In addition, hydrogen gas generated during charging of a lead-acid battery starts to be generated when the battery is charged to about 70% of the amount of discharged electricity.
This happens at a fairly rapid rate when the charge level exceeds about 90%. Furthermore, when the charge reaches about 120% or more, most of the charging current is used for water electrolysis, or gas generation. In the lead-acid battery according to the present invention, the generated hydrogen gas bubbles rise in a limited cylinder, and the electrolyte is effectively pushed up mainly by the piston action of the gas bubbles rising in the cylinder. , it is possible to move 3 to 4 times as much electrolyte as the amount of gas generated. Particularly efficient is a state in which a small amount of generated gas rises intermittently inside the cylinder. In this way, it is equipped with a gas generator that is effective in circulating the electrolyte with the generation of a small amount of hydrogen gas.
When the charge amount relative to the discharge amount is 100 to 105%, that is, the overcharge amount is 0 to 5%, the battery electrolyte concentration becomes sufficiently uniform. Therefore, there is no need to overcharge the battery by about 20%, which is the case with conventional batteries, and there is an advantage that less energy is required for charging. In addition, since the lead-acid battery according to the present invention requires only a small overcharge amount of 0 to 5%, there is little corrosion of the positive electrode grid, and the amount of corrosion after 1000 charge/discharge cycles is lower than that of conventional lead-acid batteries with the same number of charge/discharge cycles. This is 1/3 of that of the positive electrode grid of a storage battery (20% overcharge), which can significantly improve the lifespan.

As mentioned above, according to the present invention, the difference in concentration between the top and bottom of the electrolyte can be reduced even in applications where the amount of overcharge is small, and therefore the difference in specific gravity between the top and bottom of the electrolyte can be eliminated as in the conventional method. There is no need to perform overcharging for this purpose, and as a result, corrosion of the positive electrode lattice can be reduced, resulting in excellent advantages such as a significantly improved lifespan.

[Brief explanation of drawings]

The figure is a schematic diagram showing an embodiment of the lead-acid battery of the present invention. 2... Positive electrode plate, 3... Negative electrode plate, 4... Separator, 5... Electrolyte, 6... Positive electrode terminal, 7... Negative electrode terminal, 8... Gas generator, 9... Gas generating electrode,
10... Cylindrical body, 11... Suction port, 12... Discharge port.

Claims (1)

[Scope of utility model registration request] An electrolyte inlet is provided near the lower end of a cylindrical body made of an acid-resistant, electrically insulating material, and an electrolyte outlet is provided near the upper end of the cylindrical body. A lead-acid battery comprising a gas generating device equipped with a rod-shaped or wire-shaped lead alloy gas generating electrode placed in an electrolytic solution, and the gas generating electrode of the gas generating device being connected to the negative electrode side.