Performances positive pastes

The stability of BaPbOs and its effect on the performance of a battery over its useful life have also been investigated for automotive applications [12-14]. A conventional automotive cell with 1 wt.% BaPbOs in the positive paste and a control cell were formed by means of a standard high-rate formation procedure. Cell performance was then evaluated by means of a standard Battery Council International (BCI) sequence of reserve capacity and cold-cranking tests. The cell containing BaPbOs formed three times faster with 12% less input capacity. The BCI test results of the two cells were comparable. 

Voss [69] has published a comprehensive review of the effects of phosphoric acid on the performance of lead-acid batteries. This review included previously unpublished tests by Kugel, Rabl, and Woost conducted between 1926 and 1935, in which phosphoric acid was added to the positive paste at the 0.9, 2.0,2.9, or 4.0wt.% level, and at 0.9wt.% in the electrolyte. The results showed that, during cycling, the phosphoric acid concentration increases in the electrolyte but decreases in the phosphated positive active-material. It is also higher in the electrolyte when the cell is discharged. Tables 4.8-4.10 show the results of these studies. 

A).5wt.%, in either the positive paste or the negative paste or both, function as a binder and a plasticizer to improve life, capacity, and low-temperature performance. 

Pastes for positive and negative plates are prepared in separate mixers so as to avoid contamination of the positive paste with BaS04 and expander from the negative paste. Such impurities would impair the performance of positive plates. 

McGregor [51], Moseley [52], Bullock and Dayton [53] have published comprehensive surveys on the most common additives to the positive paste and their influence on the performance of lead—acid batteries. Additives to the paste for positive plates can be classified in the following major groups. 

Analogous behaviour have also other conductive metal oxides such as WO(s MoO(s x) and V20(5 jc) (0 < x < 1) [60—61]. Titanium nitride-coated porous silica powder has also been tested as additive to the positive paste enhancing its conductivity [62], but there are no data available about its effect on the performance parameters of the battery. 

Batteries produced with 3BS positive pastes cured at 90 °C, whereby the 3BS paste converts into 4BS, have good power output performance. However, the cycle life of these batteries is shorter by about 30% than that of the batteries with 4BS pastes. 

The second battery (Fig. 10.17) is a series of six cells with bipolar (or duplex) electrodes. Each cell has the same components as the first cell, i.e. zinc can, separator, positive paste and carbon current collector. The latter is not a carbon rod but the bottom face of the duplex electrode. The whole set of cells is sealed in wax. In both cells the zinc electrode rapidly develops porosity as the corrosion process occurs while the performance is largely determined by the quality of... 

Compositions of the Positive Pastes and Their Effect on Performance... 

The basics of the paste preparation were explained in Sect. 2.3.3. For the devices presented in this book, the paste was deposited onto cleaned chips using a dropcoating method [48,61]. The deposition was performed by the company Applied-Sensor (Reutlingen, Germany). A metal-wire loop is immersed in the paste and the tin-oxide suspension adhering to the loop forms a droplet, which is accurately positioned in the membrane center. After the drop deposition, the whole chip is put in a belt oven and annealed for 20 min at a temperature of 400 °C. This temperature is close to the elevated-temperature steps at the backend of the CMOS process. Consequently, we never observed a significant difference of the circuitry performance between coated and uncoated chips. The whole deposition process is, therefore, fully CMOS compatible, and no additional on-chip annealing is necessary. 

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