Study Of Preparation Technology Of Biploar Plate And Performance Of Biploar Lead Acid Battery

With the rapid development of wind power, photovoltaic microgrid and automobile industry, people have higher requirement about new mobile batteries and energy storage batteries. When compared with traditional lead acid battery, bipolar lead acid battery has greater capacity, higher energy density, faster charge and discharge rate and other advantages. The key to improving the specific energy and cycle life of bipolar lead acid battery is to find a suitable substrate material and reasonable structure design. In this work, different structures of bipolar substrate plate were designed and preparation of plate was changed to increase the binding force between lead-plaster and substrate plate, thereby the specific energy and cycle life of bipolar lead acid battery were improved.In the experiments, six structures of substrate plate were designed. If the bipolar plate was made of Pb-Sn plated titanium plate which was cold pressed on lead-calcium alloy ribs, the thickness of positive and negative lead-plaster electrode was 2.0 mm. When this kind of 4V bipolar lead acid battery was discharged at 11.23 mA/g, discharge specific capacity of positive electrode was 80.0 mAh/g. If the 4V bipolar lead acid battery was made of Pb-Sn plated wavy lead plate, the thickness of positive and negative lead-plaster electrode was 5.0 mm. This battery had a good discharge performance at different current density and a good cycling stability. During the cycle of 0.25 C charge 0.5 C discharge and 100 % DOD, the discharge specific capacity of positive electrode could be maintained between 40 and 50 mAh/g in the first 40 cycles. It illustrated that the above two structures substrate plate could improve the binding force between lead-plaster and substrate plate.In the experiments, the preparation of different positive plates using different lead-plaster formula, different mixing and curing process were also studied. Then they were used to assemble the 4V bipolar lead acid battery. The 1 C specific capacity of positive electrode of most of these batteries was higher than that of the 4V unipolar lead acid battery（44.3 mAh/g）. The positive electrodes were made of positive leadplaster which contained 9 mass% H₂SO₄（1.40 g/cm³） and cured for 90 ℃ 33 h. we used these positive electrodes to assemble the 4V bipolar lead acid batteries（4-G 3）. The specific capacities of positive electrode of this bipolar lead acid battery at different discharge current density were all higher than that of unipolar lead acid battery. When it was discharged at 11.23 mA/g, 25 mA/g, 50 mA/g, 100 mA/g, 150 mA/g, the specific capacity of positive electrode were 85.5 mAh/g, 66.8 mAh/g, 56.0 mAh/g, 44.8 mAh/g, 35.0 mAh/g. It reflected the advantage of bipolar lead acid battery discharging at high current density.Overall, in this study, the 4V bipolar lead acid battery had a shorter cycle life than the 4V unipolar lead acid battery. However, some of them were still acceptable: The positive electrodes were made of positive lead-plaster which contained 9 mass% H₂SO₄（1.40 g/cm³） and cured under 90 ℃ for 24 and 33 h respectively. we used these positive electrodes to assemble the 4V bipolar lead acid batteries（4-G2, 4-G 3）. During the cycle of 0.25 C charge 0.5 C discharge and 100 % DOD, A-G 2 and A-G 3 batteries had a higher specific capacity than that of unipolar lead acid battery in the first 15 cycles; The positive electrodes were made of positive lead-plaster which contained 6 mass% H₂SO₄（1.40 g/cm³） and cured for 80 ℃ 33 h. we used these positive electrodes to assemble the 4V bipolar lead acid batteries（B-G 4）. This battery and 4V unipolar lead acid battery had a similar initial discharge specific capacity of positive electrode and the coulombic efficiency was nearly 100 %, this battery could also maintain the discharge specific capacity unchanged in the first 30 cycles, after the discharge specific capacity declined to 50 % of initial discharge specific capacity of positive electrode, this battery could maintain the discharge specific capacity undeclined to 240 cycles at present, but the discharge specific capacity of unipolar lead acid battery kept declining.