Draw the diagram of the apparatus of a Lead batteries.

The first working sample was created by Gaston Plante (France) in 1859. The two lead sheets separated by separator linen, coiled and inserted into a jar of sulfuric acid. Current-producing half reaction: on the positive electrode(+) PbO₂ + 3H⁺ + HSO₄^- +2e « PbSO₄¯ + 2H₂O; on the negative electrode(–) Pb + HSO₄^- « PbSO₄¯ + H⁺ +2e; total current-producing reaction: discharge PbO₂ + Pb + H₂SO₄ « 2 PbSO₄ + 2H₂O, EMF = 2.047 V at 250 ° C. When discharging spent sulfuric acid, the electrolyte is diluted with water. Electrodes formed on both the slightly soluble lead sulfate (II). Open circuit voltage and the discharge/charge curves: ( - ) Pb | H₂SO₄ | PbO₂ (+).

The capacity is quite depending of the current and the temperature.

The main application area of these batteries is Accumulators for cars. Nominal voltage produced by such a battery is 2 volts. Single batteries are connected in series to obtain higher voltage values. For example to create car 12 V accumulator it is necessary to connect 6 batteries.

Advantages: reliability; durability; low production cost; the possibility of repeated recycling. Disadvantages: Lead - metal, dangerous for the environment; long charging process; low productivity at low temperature. Care and maintenance: Keep only in the charged state (Deep discharge of the lead battery is very harmful for him); Regularly topped up with distilled water. When corrosion of lead and recharging the water is decomposed. In recent years, issued sealed maintenance-free SA. The room in which the charge is made, should be well ventilated (releases toxic Stibine SbH3 and arsine AsH3).

 

21. What the curves shown in this figure? Compare them and make assumptions about their nature

We see the dependence of the voltage on the capacity. 4 types of curves discharge differing discharge current are shown. The first curve corresponds to the discharge at C / 5, which is equal to 0.5 A. The curve has a maximum source voltage and the maximum voltage value for the entire discharge time. The second curve shows the dependence of the discharge at C/2, which corresponds to 1.3 A. The initial voltage and common voltage during discharge is less than C/5. The third curve corresponds to the category at 1C or 2.6 A. It has a performance worse than the first two. The fourth curve is the lowest voltage because the discharge current equal to 2C or 5.2 A. Based on the chart one can conclude that the voltage decreases with an increase in discharge current. It is not much impact on the capacity of the battery, although the maximum discharge capacity decrease.