Glass fleece separators

For the separation of such batteries, gel construction and microfiber glass fleece separators again compete because of the deep discharge cycles, the gel construction with its lower tendency to acid stratification and to penetration shorts has advantages for the required power peaks, microfiber glass fleece construction would be the preferred solution. The work on reduction of premature capacity loss with lead-calcium alloys has shown that considerable pressure (e.g., 1 bar) on the positive electrode is able to achieve a significantly better cycle life [31-36], Pressure on the electrodes produces counter pressure on the separators, which is not unproblematic for both separation systems. New separator developments have been presented with... 

AMER-SIL s. a. [861 has recently introduced a micrufiber glass fleece separator ( AMER-GLASS ). 

Microfiber glass fleece mats are typically produced from a blend of 20 - 30 percent glass microfibers <1 //m in diameter, with the balance of the glass fibers thicker (3 - 10 //m) and longer (cf. Fig. 1), on a specialized paper machine (Fou-drinier), since this is the only way of achieving the desired tensile strength without binder. The material is supplied in roll form, even though it is normally not processed into pockets, which are not required due to the absence of free electrolyte. The classification here as a leaf separator should be seen in this sense. 

In contrast to most conventional separators for flooded batteries, separators for gel batteries have ribs positioned not only towards the positive plate, but also towards the negative plate in order to facilitate the gel-fllling process. For batteries with pasted positive plates, the separator is usually laminated with a glass fleece, which protects the positive plate against shedding, especially in cycle applications. Although this surface fleece stabilizes the active material, the present design of gel batteries cannot prevent completely the expansion of the positive material and the occurrence of PCL-2. The most important characteristics of separators used in gel batteries are listed in Table 7.2 (adapted from Ref. 12). 

The development of the starter battery in Japan has taken an independent course (see Sec. 9.2.1.2), visibly expressed by the separator s thick glass mat and its lack of spacing ribs (cf. Fig. 19). The cellulosic backweb impregnated with phenolic resin, generally in use until around 1980 and largely identical to the separator of the same type already mentioned has been completely replaced by thin ( 0.3 mm) fleece materials made of organic fibers. 

Because of the increased shedding with these alloys, pure leaf separation is hardly suitable. Separations with supporting glass mats or fleeces as well as microfiber glass mats provide technical advantages, but are expensive and can be justified only in special cases. Also under these conditions of use the microporous polyethylene pocket offers the preferred solution [40]. Lower electrical properties at higher temperatures, especially decreased cold crank duration, are battery-related the choice of suitable alloys and expanders gains increased importance. 

Synthetic wood-pulp separators (SWP). So-called synthetic wood-pulp (SWP) separators are used widely in Japan for automotive batteries. These are fleeces made from fibrillated polyethylene or polypropylene and small amounts of additional fibres (e.g., polyester fibres) sometimes, the fleeces are also filled with silica. The organic sheets are laminated with a glass mat, which serves to stabilize the positive active-material [39]. 

Translucent sandwich panels for the side-facades were also made of glass-fiber-reinforced polyester composites (see Figure 1.8). The sandwich panels consisted of two layers separated by a composite fiber sheet with trapezoidal corrugations. The surface of the facade panels was finished with fleeces that also provide resistance to aging and U V radiation. As the main function of these facade elements was thermal insulation, the sandwich panels were filled with aerogels. They were therefore able to provide a K-value of 0.4 W m with a panel thickness of only 50 mm [18]. In terms of building fire considerations, a sprinkler system was installed as an active fire protection. 

Because of the increased shedding with these alloys, pure leaf separation is hardly suitable. Separations with supporting glass mats or fleeces as well as microfiber glass mats provide technical advantages, but are expensive and can be justified only... 

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