Construction, batteries bipolar

Despite the fact that the zinc/ ferricyanide system employs an alkaline electrolyte, the electrode reactions are quite similar to those in zinc/halogen batteries and battery constructions are usually bipolar too. 

Cell geometry, such as tab/tenninal positioning and battery configuration. strongly influence primary current distribution. The monopolar construction is most common. Several electrodes of the same polarity may be connected in parallel to increase capacity. The current production concentrates near the tab connections unless special care is exercised in designing the current collector. Bipolar construction, wherein the terminal or collector of one cell serves as the anode and calliode of llie next cell in pile formation, leads to greatly improved uniformity7 of current distribution. 

Figure 24. Principle construction of a bipolar 3 Volt alkaline Mn02 - Zn battery.

Principally the construction of a bipolar battery is not size limited. The plates can be as large as needed with the possibility of any shape desired. Like in fuel cell systems battery plates can be built in m dimensions. This is an important aspect, because regular plate batteries are size limited by the current collector grids like the lead-acid automobil starter battery, which get unproportionally heavy at larger sizes and heavy loads. Generally we can expect energy... 

Historically, the concept of arranging the cells in bipolar and monopolar fashion was known before 1800, when Volta assembled batteries [3]. There are several advantages and disadvantages associated with the construction and operation of monopolar and bipolar cells [4,5]. They are noted in Table 5.1. 

A bipolar lead-acid battery eliminates grouping of positive and negative plates and the connections between cells. Bipolar battery construction shortens the current path between the positive and negative terminals of the battery, which reduces the battery s internal resistance to current flow and improves power delivery. The bipolar battery configuration is particularly suitable for high-voltage batteries because bipolar construction requires less space compared to conventional lead-acid batteries. 

MulticeU Bipolar Construction with Single-Activator Reservoir. Lithium anode reserve batteries, using bipolar constraction, are relatively few in number and always developed for specific applications. The bipolar constraction—one component used as hotii the anode collector of one cell and the cathode collector of the next cell in the stack— is not unique to the lithium reserve battery, but an adaptation of techniques used in other types of batteries. There are several advantages of the bipolar constraction ... 

Figure 20.11 is an illustration of a reserve Uthium/thionyl chloride battery using a bipolar plate construction. This battery weighs approximately 5.4 kg and has a volume of 2000 cm. Activation of the reserve battery is accomplished by supplying an electric pulse to the battery by firing an electric squib or actuator or by some mechanical means. This type of reserve battery has been used chiefly in artillery shells for electronic fuze power supplies and in missiles for the electronic power supply. Therefore the electric pulse can be supplied prior to firing or at the time of launch. However, for artillery fiize power supplies, the battery is usually activated by the launch acceleration (set back) and/or the spin forces. The accel-... 

The other example, called the nickd/zinc battery [(—) Zn/KOH/NiOOH (+)], has attracted more attention in two different versions from the viewpoints of application and cell design one is the small cyhndrical consumer cell [148, 149], the other is the flat-plate module for electrotraction [149, 150]. A very interesting review with an extensive collection of references was pubHshed in 1992 [151]. In 1996, an improved bipolar construction of this battery was presented [152]. The most recent version was described by Humble and co-authors [153] a nickel/zinc microbattery developed for direct installation and use in autonomous microsystems. 

---