Battery lead storage

The lead storage battery, the largest single user of lead and its compounds, is made possible by the high degree of reversibiUty, both chemical and physical, in the fundamental chemical reaction... 

Blei-rhodanid, n, lead thiocyanate, -rohr, n., -rShre, /. lead tube or pipe, -rostprozess, m. lead roasting, -rot, n. red lead, minium, -safran, m. orange lead, -salbe, /. (Pharm.) lead ointment, cerate of lead subacetate, -salpeter, m. lead nitrate, -salz, n. lead salt, specif, lead acetate, -sammler, m. lead accumulator lead storage battery. 

A lead storage battery needs sulfuric acid to function. The recommended minimum concentration of sulfuric acid for maximum effectivity is about 4.8 M. A 10.0-mL sample of battery acid requires 66.52 mL of 1.325 M KOH for its complete neutralization. Does the concentration of battery acid satisfy the minimum requirement (Note Two H+ ions are produced for every mole of H2SO4.)... 

The rechargeable 12-V lead storage battery used in automobiles consists of six voltaic cells of the type shown in Figure 18.12. A group of lead plates, the grids of which are filled... 

When a lead storage battery is supplying current, the lead in the anode grids is oxidized to Pb2+ ions, which precipitate as PbS04. At the cathode, lead dioxide is reduced to Pb2+ ions, which also precipitate as PbS04. 

To recharge a lead storage battery, a direct current is passed through it in the proper direction so as to reverse the above reaction. In an automobile, the energy required to carry out the recharging comes from the engine. 

In a folly charged lead storage battery, tire electrolyte consists of 38% sulfuric add by mass. The solution has a density of 1.286 g/cm3. Calculate E for tire cell Assume all the H+ ions come form tire first dissociation of H2SO4, which is complete. 

A 6 volt lead storage battery contains 700 grams of pure HjSO/fJ dissolved in water. 

Fig. 22-10. Cells from Edison and lead storage batteries (schematic).

For alkaline storage batteries requirements are often demanded exceeding by far those for lead storage batteries. The reason is that the suitable materials for the positive electrode are very expensive (silver oxide, nickel hydroxide) and thus the use of these storage batteries is only justified where requirements as to weight, number of cycles, or temperature range prohibit other solutions. Besides a few standardized versions — mainly for nickel-cadmium batteries — this has led to the existence of a large diversity of constructions for special applications [4-6, 108, 109],... 

Values taken from S. Glasstone. Thermodynamics for Chemists. D. Van Nostrand Company Inc., Toronto, p. 443 (1947). The values tabulated in this reference were taken from D. N. Craig and G. W. Vinal, J. Res. Natl. Bur. Stand.. Thermodynamic Properties of Sulfuric Acid Solutions and Their Relation to the Electromotive Force and Heat of Reaction of the Lead Storage Battery", 24, 475-490 (1940). More recent values at the higher molality can be found in W. F. Giauque. E. W. Hornung. J. E. Kunzler and T. R. Rubin, The Thermodynamic Properties of Aqueous Sulfuric Acid Solutions and Hydrates from 15 to 300° K", J. Am. Chem. Soc.. 82, 62-70 (1960). 

In an electrochemical cell, electrical work is obtained from an oxidation-reduction reaction. For example, consider the process that occurs during the discharge of the lead storage battery (cell). Figure 9.3 shows a schematic drawing of this cell. One of the electrodes (anode)q is Pb metal and the other (cathode) is Pb02 coated on a conducting metal (Pb is usually used). The two electrodes are immersed in an aqueous sulfuric acid solution. 

Figure 9.3 The lead storage battery. The key to obtaining electrical energy from a redox chemical reaction is to physically separate the two half-cell reactions so that electrons are transferred from the anode through an external circuit to the cathode. In the process, electrical work is accomplished.

To apply the features that characterize galvanic cells, Example describes the lead storage battery. 

The electrical current needed to start an automobile engine is provided by a lead storage battery. This battery contains aqueous sulfuric acid in contact with two electrodes. One electrode is metallic lead, and the other is solid Pb02. Each electrode becomes coated with solid PbSOq as the battery operates. Determine the balanced half-reactions, the overall redox reaction, and the anode and cathode in this galvanic cell. 

Electrons appear as products, so this half-reaction is the oxidation, which takes place at the anode. The lead electrode is an active anode in a lead storage battery. 

C19-0022. Using the appropriate values from Table 19-1. calculate E ° for one cell of a lead storage battery. (Six of these cells are connected in series in an automobile storage battery.)... 

The lead storage battery provides electrical power in automobiles. It is well suited for this use because it supplies the large current needed to drive starter motors and headlights and can be recharged easily. Figure 19-20 shows the lead storage cell in a schematic view. The half-reactions are the subject of Example ... 

C19-0050. What are the half-reactions for these redox processes (a) Aqueous hydrogen peroxide acts on Co, and the products are hydroxide and Co , in basic solution, (b) Methane reacts with oxygen gas and produces water and carbon dioxide, (c) To recharge a lead storage battery, lead(II) sulfate is converted to lead metal and to lead(IV) oxide, (d) Zinc metal dissolves in aqueous hydrochloric acid to give ions and hydrogen gas. 

C19-0090. Explain why the lead storage battery, despite being the battery of choice for automobiles, is not suitable for space flights. 

C19-0096. A dead 12-V lead storage battery has 4.80 g of PbSOq deposited on each of its anodes. It is... 

Because of these damaging effects, most uses of lead that involve direct exposure for humans are being phased out. Unleaded gasoline and lead-free paints have replaced two former major commercial uses of lead. Lead has proved to be Indispensable, however, in the lead storage battery, which now provides the major use of this metal. Although leakage from damaged batteries is still a potential hazard, contemporary batteries are manufactured in such a way that human exposure to battery contents is minimized. 

The insoluble hydroxides of Cd and Ni deposit on the electrodes. Hence, quick reversals of half-reactions occur during recharging. These batteries are costlier than lead storage batteries, but they have a longer term of existence. 

The lead storage cell (six of which make up the lead storage battery commonly used in automobiles) will be discussed as an example of a practical cell. The cell, pictured in Fig. 14-2, consists of a lead electrode and a lead dioxide electrode immersed in relatively concentrated H2S04 in a single container. When the cell delivers power (when it is used), the electrodes react as follows ... 

Pb02 is the oxidizing agent and lead is the reducing agent in the lead storage battery. The chemistry of the battery can be summarized by the following equation ... 

In the lead storage battery, insoluble lead sulfate, PbS04(s), is produced at both the anode and cathode during cell discharge. 

Used industrially in the manufacture of semiconductors, and as a fumigating agent. It may be a by-product formed during charging of some lead storage batteries. 

The availability of lead-based paints, discarded oil filters, used crankcase oil, lead storage batteries, or pastures contaminated by industrial lead operations make lead one of the most common... 

Institute of Electrical and Electronic Engineers, Inc. (IEEE), IEEE RP 484. Design and Installation of large Lead Storage Batteries for Generating Stations and Substations. IEEE, New York, NY, 1987. 

---