Lead tubular-plates

Fig. 2. Cutaway view of a tubular positive lead—acid battery, (1) Positive tubular plate (2) iiegatwe plate (3) separator (4) connecting strap (5) ceU cover (6)...

The tubular positive plate uses rigid, porous fiber glass tubes covered with a perforated plastic foil as the active material retainer (Fig. 2). Dry lead oxide, PbO, and red lead, Pb O, are typically shaken into the tubes which are threaded over the grid spines. The open end is then sealed by a polyethylene bar. Patents describe a procedure for making a type of tube for the tubular positive plate (90) and a method for filling tubular plates of lead—acid batteries (91). Tubular positive plates are pickled by soaking in a sulfate solution and are then cured. Some proceed directiy to formation and do not requite the curing procedure. 

Figure 7. Section of a tubular plate a, lead-alloy spine (grid) b, active material (PbOz) c, tube, (in this example, fabric of polyester fibers) d, bottom seal of plastic caps.

Figure 9. Conversion of grid material into lead dioxide (Pb02) by corrosion spine of a positive tubular plate. New plate 3mm diameter means 7.1 mm2 cross-section (nr2 with r = 1.5mm). Aged plate reduction of r by 0.03 x 15 = 0.45mm means nr2 = 3.5 mm2.

Fig. 5.6 (a) Tubular plates for lead-acid cells, (b) Cross-section showing central lead current collector, active material and porous separators... 

Tubular plates have been made with chemically prepared lead dioxide and 2.2 or 3.8wt.% sodium sulfate in the positive active-material [44]. Test results on cells cycled at constant-current are shown in Table 4.7. It was concluded that sodium sulfate increases the utilization of material by dissolving to create a more porous structure in the positive plate. It was also noted that graphite has an even greater effect in the same concentration range (see Section 4.4.7). 

Tube filling. The tubular plates are filled, under pressure, with a slurry of 3BS or 4BS positive pastes diluted with water, or with a suspension obtained from leady oxide and red lead... 

However, tubular plates have some disadvantages as well. Their production is a bit more expensive. Furthermore, the contact area between the lead current collector and the active material is reduced when cylindrical spines are used. Thus, under continuous heavy current drains, the increased current density at the spine active mass interface leads to higher polarization and local heating, which may cause cracking of the CL. 

Most often, high percentage (65 wt%) red lead and leady oxide blends are used for filling positive tubular plates for bofli traction and stationary batteries. 

Leady oxide manufacture is potentially very hazardous. It is therefore vital to take adequate measures to minimise, or even eliminate altogether, possible lead dust emissions out to the working environment and thus exposure of the personnel which would cause health problems. This is achieved by the use of a closed (isolated) leady oxide production equipment and transport pipes from the storage silos to the paste mixing unit. Special attention should be paid to file manufacture of tubular battery plates. Until recently, tubular plates were filled with a dry mixture of leady oxide and red lead powders. 

An overview of the general design and the properties of tubular plates is presented in Chapter 4.10. Here, we will discuss the process of filling tubular plates with lead oxides or suspension. 

Figure 10.11 Cut-away of a lead/acid motive power cell showing Gauntlet type non-woven terylene tubular plate positive electrodes (cf Fig. 10.6). Photograph supplied by Chloride Technical Ltd. 

Lead-battery electrodes can be made as a flat plate with a lead grid as the current collector or as a tubular plate design with a lead rod current collector in the center of tubes. Monopolar electrode current collectors have a conductive lead grid that connects with the terminal. The current collector physically supports the electrode and also collects and carries the current to the electrical system. 

Handling machinery, wheelchairs, electrically-assisted pedal cycles, etc. Cost, Wh/kg Tubular-plate flooded lead-acid. Reinforced flat plate flooded lead-acid. VRLA". Lithium polymer... 

The overall dimensions of these tubular plate-type cells also accord to the lEC Standard 60 254-2, Lead-acid traction batteries, part 2, cell dimensions for traction batteries . 

Table 2.4 Lead acid traction cells with tubular plates, series L, dimensions conforming to lEC 60 254 2. 

Forerunners of these more powerful batteries of the tubular plate type and also of the grid plate type have been tested in electric road vehicles. Naturally the classic lead-acid battery has a limit which fies far below the theoretical value of 161 Wh/kg. By showing the shares of weight of conductive material, excess mass, and excess electrolyte and inactive material. Figure 2.4 explains why the possibilities for improvement of the energy/weight ratio are so few. 

Table 2.6 Lead-acid traction batteries, monobloc batteries with positive tubular plates (DIN 43 598 part 1).

Nominal capacity after 10 discharges electrolyte density 1.28 + 0.01 kg/L electrolyte temperature 25 °C. Table 2.7 Lead-acid traction batteries in plastic trays with single cells and positive tubular plates (DIN 43 598 part 2). ... 

A further selection criterion is provided by the different limit temperatures in the electrolyte, as is also depicted in Table 3.2. The use of a particular battery system becomes questionable when the ambient temperature approaches its maximum permissible temperature. Nickel/cadmium batteries have a significantly lower limit temperature than lead-acid batteries. The systems thus dictate that lead-acid batteries should exclusively be used when the ambient temperature exceeds 35 °C to 40 °C. In the case of extreme ambient temperatures, however, a renewal of batteries should also be planned for, in order not to jeopardize the long service life typical of the system, even when using tubular plate batteries. 

ZVEI has created a diagram (Figure 5.3) to determine the expected service life of a lead-acid traction battery with positive tubular plates this diagram is a good basis for calculation, but it has to be noted that this diagram is only applicable for cells with a liquid electrolyte. For other cell types, e.g., the VRLA types, the diagram cannot be used. 

Product standards comprise main overall dimensions, weights, and electric data on production series or on single parts. Example DIN 43 595, titled Lead-acid accumulators tubular plate-type cells for water- and land-bound vehicles, low maintenance type. Nominal capacities main dimensions. ... 

DIN 40 736, Parts 1 and 2 Lead-acid accumulators stationary battery cells with positive tubular plates Capacities, main dimensions, weights. 

FIGURE 3.1 Lead-acid battery electrode stmctures (a) flat and tubular plates (b) pasted flat electrode, in which the two grids on the left are made of carbon and lead, respectively. After the grid is pasted and cured, the electrode is formed as shown at right, ([a] From http //www.check thatcar.com/carfaq2.asp. [b] From A. Kirchev et al., J. Power Sources, 196(20), 8773-8788,2011.)... 

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