Where the acidic aqueous solution as the electrolyte batteries} collectively referred to as the acidic batteries, which is the most typical lead acid battery . The most typical ones are lead-acid batteries {. The main advantages of acid batteries are high operating voltage, wide operating temperature, good discharge performance at high and low rates, abundant raw material sources, and low price. Its disadvantage is that the energy density is low, making its volume and weight larger.   microporous rubber spacer , microporous plastic spacer or other materials, the battery shell is made of hard rubber, engineering plastics , glass fiber reinforced plastic and other materials.

I. Construction

Acid storage batteries are mainly composed of three parts: the container, the pole plates and the partitions. Acid battery container is used to store electrolyte and support the pole plate, so it must have to prevent acid leakage, corrosion resistance, solid and high temperature resistance and other characteristics. According to different materials, the commonly used lead-acid battery containers have four kinds of glass tanks, lead-lined wood tanks, plastic tanks and hard rubber tanks.

General offshore oil project using acid battery pole plate using lead-antimony alloy is made into a grid format with an active substance pressed into the grid. The active substance of the positive plate is lead dioxide(PbO2), and the active substance of the negative plate is spongy pure lead. In order to increase the capacity of the battery positive and negative plates are made of many pieces, respectively, connected in parallel, connected into two groups, constituting the positive and negative battery. Each group of positive and negative plates composed of a single battery voltage of about 2V or so, in practice, often 3 or 6 of the same single battery connected in series to become a group. Battery negative plate is always more than a positive plate, each positive plate clamped in the two negative plates, so that the positive plate on both sides of the chemical reaction, resulting in the same expansion and contraction, reducing the plate bending opportunities, thereby extending the service life of the plate, because the negative plate in the charging and discharging process of expansion and contraction of the plate is much less than the positive plate, the system     &nbsp The outer most two negative plates have only one side with the positive side of the chemical reaction, so its thickness is thinner than the middle of the negative plate.  

The role of the separator plate is to insulate the positive and negative plates of the battery from each other, and it can be made of wood, hard rubber and plastic. In order to allow the electrolyte to flow freely, the construction of the separator should be porous, but not so that the shedding of the active substance through the separator and contact with the neighboring pole plate.

II. Discharge principle

The two sets of plates of a lead battery are inserted into a dilute sulfuric acid solution to produce a voltage by a chemical change. Passed into the direct current (charging), in the positive plate on the lead oxide into a brown lead dioxide (PbO2), in the negative plate on the lead oxide into a gray fluffy lead (Pb, also known as spongy lead). Lead battery discharge, the positive and negative plates on the active material are absorbed sulfuric acid chemical change, and gradually become lead sulfate (PbSO4), when the positive and negative plates on the active material have become the same lead sulfate, the voltage of the battery drops to the point that can not be discharged again. At this time it is necessary to charge the battery to restore it to its original lead dioxide and fluffy lead, so that the battery can continue to discharge again. The chemical change that occurs in the battery is reversible and is expressed in the following equation: 

Chemical expression for charging and discharging

It can be seen from the above equation that the density of dilute sulfuric acid of the electrolyte increases during charging; the density decreases during discharge due to the formation of water. The electric potential of an acid battery is mainly related to the density of the electrolyte. High density, electric potential is also high. The following relationship is expressed by the empirical formula:

where E - electric potential of the battery, V;

d - density of the electrolyte.

Thirdly, internal resistance and capacity

The internal resistance of an acidic battery consists of the resistance of the pole plates, the resistance of the electrolyte, and the resistance of the pole-plate connecting parts.

When the battery is charging, the density of electrolysis changes, and the effective material on the pole plate changes, so the internal resistance of the battery also changes. The internal resistance of the battery is minimized after charging, and increases when discharging. For the battery used, its internal resistance can be calculated by the following formula:

where:

R--internal resistance of the battery, Ω;

E--open-circuit voltage, V;

U - terminal voltage at operation, V;

I - discharge current, A.

219}}The capacity of the battery indicates the ability of the battery to store electrical energy, and the capacity of a marine battery is generally measured in ampere-hours at a 10-hour discharge rate. For example, a 250 ampere-hour battery can be discharged for 10 hours at a current of 25 amperes. However, the same battery will not give a capacity of 250 ampere-hours at a discharge rate of 1 hour, and in fact will be less than 250 ampere-hours. At discharge rates other than the 10-hour discharge rate a suitable capacity factor should be multiplied, as shown in Table 2-58.  

Capacity factor for acid battery

D. Usage

Charging Methods

initial charging. New or long term stock batteries need to undergo initial discharge before use, the steps are as follows:

① Firstly, screw out the water filling cap and remove the seal of the small holes on the cap, so as to make it air free.

② add the prepared electrolyte, the density of 1.285 (note that when preparing the electrolyte, sulfuric acid should be injected into the distilled water), added to the bulkhead above the 10 ~ 15mm.

③ after the electrolyte is added, the battery will be left to stand for 2 ~ 3h You can connect the positive and negative terminals of the battery to the positive and negative terminals of the power supply and prepare for discharge.

④ Initial charging is performed according to the current and time specified in Table 2-59. The first stage of current charging causes the terminal voltage of each small cell to rise to 2.4V, and then switch to the second stage of current charging until the voltage and electrolyte ratio essentially cease to change within 3h.  

Main parameters of battery discharge

Recurring charging method. Acid battery recurrent charging in two stages, charging current and time see table 2-59. the first stage of charging, so that the battery voltage rises to about 2.4V per battery, and then transferred to the second stage of charging, until the electrolyte density reaches 1.285 and the top and bottom uniformly consistent, then charging is complete.

Electrolyte Adjustment and Replacement

Battery in the charging process, due to the occurrence of gas so that the electrolyte in the reduction of water and the liquid level is reduced. Sulfuric acid, although there is also a little splash, but the loss is very small, so supplement the liquid level to the original height, only to add water, do not add acid. If the density of electrolyte after charging is lower than the original value, should be in accordance with the requirements of the manufacturer, can be added to the density of 1.35 ~ 1.40 dilute sulfuric acid to adjust, if the density is higher than the original value, can be added to adjust the distilled water.  

Adjustment of the density of the electrolyte should be carried out after the normal charging. Then use half of the normal charging current, and then charge for 30 minutes or 1 hour, in order to make the electrolyte mix evenly, if the measured density is still different then it should be repeated according to the above method until the density of battery pack reaches the specified.