To put it plainly, charging is the transformation of electrical energy into chemical energy. When discharging, chemical energy is converted into electricity!
Lead accumulator
The most commonly used, the plate is made of lead alloy grid, electrolyte for dilute sulfuric acid. The bipolar plate is covered with lead sulfate. But after charging, the anode plate of lead sulfate into two lead oxide negative electrode lead sulfate into lead metal. When the discharge occurs, the opposite direction of the chemical reaction.
The electric potential of lead-acid battery is about 2 volts, batteries commonly used in series 6 or 12 volt battery discharge. When sulfuric acid concentration decreased, measuring electrolyte density method can be used to judge the battery charging or whether charging process can end.
The advantage of lead-acid battery is that the electromotive force is stable when it is discharged. The disadvantage is that it is smaller than the energy (unit weight, storage energy), and it is corrosive to the environment
The positive plate group, negative plate group, electrolyte and containers. The positive plate after charging is Tan two lead (PbO2), the negative plate is fluffy lead gray (Pb), when the two electrode placed in a concentration of 27% to 37% sulfuric acid (H2SO4) in aqueous solution, and lead sulfate the electrode reactions, two valence lead positive ions (Pb2+) transferred to the electrolyte, leaving two electrons in the negative plate (2e-). The positive and negative gravity around lead positive ions gathered in the negative plate and the positive plate, there is a small amount of lead in two water molecules under the effect of electrolyte (PbO2 the price of two) into the electrolyte, oxygen ions and water molecules combine to make two lead into an unstable substance, Pb hydroxide dissociable (OH4). By 4 the price of lead hydroxide ions (Pb4+) and 4 hydroxyl (OH) - 4:.4 The price of lead ions (Pb4+) in the positive plate, the positive plate is positively charged. Because of the negative plate is negatively charged, so the two plates have a certain potential difference, this is battery electromotive force. When connected to the external circuit, the current from the positive to the negative. In the process of discharge, electronic negative plate the external circuit by the constant flow positive plate, then in the internal electrolyte due to sulfate molecule ionization into hydrogen ions (H+) and sulfate anion (SO42-), in the role of the ion electrostatic field, two kinds of positive and negative ions respectively to move, reach the negative plate of sulfate anion and cation combined into lead sulfate lead (PbSO4). The positive plate, because the electronic circuit from the inflow, and the 4 is the price of lead ion (Pb4+) synthesis of 2 valence lead positive ions (Pb2+), and immediately with the sulfate anion binding near the positive plate of lead sulfate attached to the cathode.
With the discharge battery, positive and negative plate by sulfide, and sulfate in the electrolyte decreased gradually, and more water, which leads to the decline in the proportion of electrolyte in actual use, by measuring the proportion of electrolyte to determine the level of battery discharge. Under normal circumstances, lead battery should not be excessive discharge, otherwise it will make and active lead sulfate crystal material mixed together to form a small larger body, which not only increased plate resistance, but also in charge when it is difficult to restore, directly affect the storage pool capacity and life. Lead battery is the inverse process of discharge.
Lead the working voltage of battery smooth, using temperature and use current range, charging hundreds of circulation, good storage performance (especially suitable for dry charged storage), low cost, so it is used widely. The new lead alloy, can improve the performance of lead-acid battery. If use lead calcium alloy grid, can ensure the lead-acid battery floating current minimum, reduce add water and prolong its service life; the use of lead lithium alloy casting positive grid, it can reduce self discharge and meet the needs of sealing. In addition, the opening type lead-acid battery will gradually changed sealed and acid proof, explosion-proof and hydrogen type lead-acid battery.
蓄电池的放电,正负极板都受到硫化,同时电解液中的硫酸逐渐减少,而水分增多,从而导致电解液的比重下降在实际使用中,可以通过测定电解液的比重来确定蓄电池的放电程度.在正常使用情况下,铅蓄电池不宜放电过度,否则将使和活性物质混在一起的细小硫酸铅晶体结成较大的体,这不仅增加了极板的电阻,而且在充电时很难使它再还原,直接影响蓄池的容量和寿命.铅蓄电池充电是放电的逆过程.
铅蓄电池的工作电压平稳、使用温度及使用电流范围宽、能充放电数百个循环、贮存性能好（尤其适于干式荷电贮存）、造价较低,因而应用广泛.采用新型铅合金,可改进铅蓄电池的性能.如用铅钙合金作板栅,能保证铅蓄电池最小的浮充电流、减少添水量和延长其使用寿命；采用铅锂合金铸造正板栅,则可减少自放电和满足密封的需要.此外,开口式铅蓄电池要逐步改为密封式,并发展防酸、防爆式和消氢式铅蓄电池.
