Alkaline-manganese batteries

The growth of alkaline batteries is strictly due to a reduction in power requirements. C-Zn batteries had not been able to meet the energy requirements for satisfactory performance of disc players, automatic cameras, camera flash units, toys, and newly developed motors, displays, and electronic devices. The power requirements for these devices, however, can be met with alkaline-manganese rechargeable batteries. 

Major improvements in the performance of alkaline batteries were introduced around 1988 with the introduction of the plastic label construction feature instead of a cupboard insulation tube over the cell body and a steel outer jacket. Battery designers claim that deployment of this insulating plastic label provided a 15 to 20% increase in the internal volume, which allowed for additional space for the active materials needed for performance enhancement. Material scientists believe that the use of advanced materials and improvements in the module s construction have demonstrated significant improvement in the battery s capacity. 

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Fig. 5. Cutaway view of typical R20 or "D"-size alkaline manganese battery showing components and the coiiesponding materials of constmction (8).

Fig. 6. Alkaline—manganese battery operating voltage as a function of remaining capacity (21).

Fig. 8. Effect of temperature on relative discharge performance of a fresh "D"-si2e battery for service on simulated ratio use, 25- Q 4-h/d test for (a) an alkaline—manganese battery undergoing 260 h of service, and (b) a carbon—2inc battery undergoing 70 h of service (22).

Batteries using an alkaline solution for electrolyte are commonly called alkaline batteries. They are high-power owing to the high conductivity of the alkaline solution. Alkaline batteries include primary batteries, typical of which are alkaline-manganese batteries, and secondary batteries, typical of which are nickel-cadmium and nickel-metal hydride batteries. These batteries are widely used. 

The discharge of alkaline-manganese batteries comes from the electrochemical reactions at the anode and cathode. During discharge, the negative electrode material, zinc, is oxidized, forming zinc oxide at the same time, Mn02 in the positive electrode is reduced (MnOOH) ... 

The initial voltage of an alkaline-manganese dioxide battery is about 1,5 V. Alkaline-manganese batteries use a concentrated alkaline aqueous solution (typically in the range of 30-45 % potassium hydroxide) for electrolyte. In this concentrated electrolyte, the zinc electrode reaction proceeds, but if the concentration of the alkaline solution is low, then the zinc tends to passivate. 

Figure 1. Cell construction of an alkaline-manganese battery...

The cell construction of an alkaline-manganese battery is shown in Fig. 1. The steel can serves as a current collector for... 

Figure 2 shows a comparison of the discharge characteristics between alkaline-manganese batteries and Leclanche batteries. The capacity of the alkaline-manganese batteries is about three times as large as that of the Leclanche batteries. 

Amalgamated zinc powder has been used as the negative material to prevent zinc corrosion and zinc passivation. Recently, from the viewpoint of environmental problems, mercury-free alkaline-manganese batteries were developed by using zinc powder with indium, bismuth and other additives [2-4]. Adding indium to zinc powder is the most effective way to improve the characteristics of the cells [3]. Figure 3 shows the variation in the internal impedance of the cells according to the additive content of the zinc powder. 

Sanyo Electric Co., Ltd. Alkaline Manganese Battery Catalogue, 1995. 

Continuous research in primary alkaline manganese batteries ended up in the development of rechargeable alkaline manganese (RAM) cells. The design of these cells dated to 1975 [1], These batteries are basically an extension of the primary alkaline batteries. They also use zinc for the negative electrode, manganese dioxide for the positive electrode, and an aqueous solution of potassium hydroxide for the electrolyte. 

Total life cycle analyses may be utilized to establish the relative environmental and human health impacts of battery systems over their entire lifetime, from the production of the raw materials to the ultimate disposal of the spent battery. The three most important factors determining the total life cycle impact appear to be battery composition, battery performance, and the degree to which spent batteries are recycled after their useful lifetime. This assessment examines both rechargeable and non-rechargeable batteries, and includes lead acid, nickel cadmium, nickel metal hydride, lithium ion, carbon zinc and alkaline manganese batteries. 

The most common primary batteries in use today are the zinc-carbon and the alkaline-manganese battery systems. Together, they constitute in excess of 90% by weight of the total consumer battery market in Europe. Consequently, particularly within the realm of battery recycling, the term primary battery is often used to describe just these two systems. 

Specifically the Directive prohibits the marketing of general purpose alkaline-manganese batteries containing more than 0.025% mercury (0.05% for special purpose types). Furthermore it calls for the marking and separate collection for recovery or... 

Lead is sometimes still used in both battery systems. In zinc-carbon batteries it is employed chiefly as an alloying addition to improve the forming characteristics of the zinc can, and additionally acts as a corrosion inhibitor. In alkaline-manganese it has found use as a plating alloy on the brass nail to reduce gassing. In zinc-carbon cells, the lead content is in the order of 0.02% and in those alkaline-manganese batteries where lead is still used, the addition is at a level of a few parts per million. 

A significant proportion of the cost of these two operations resulted from the need to capture and treat mercury. But since zinc-carbon and alkaline manganese batteries... 

Table 4. Estimated Cost Benefits and Disadvantages per Tonne of Scrap Charged for a 1% Addition of Market Mix Zinc Carbon and Alkaline Manganese Batteries in a Typical EAF...

Alkaline manganese batteries containing more than 0,025 % mercury by weight placed on the market as from the date laid down in Article 11(1). 

SEC. 203. LIMITATIONS ON THE SALE OF ALKALINE- MANGANESE BATTERIES CONTAINING MERCURY. No person shall sell, offer for sale, or offer for promotional purposes any alkaline-manganese battery manufactured on or after the date of enactment of this Act, with a mercury content that was intentionally introduced (as distinguished from mercury that may be incidentally present in other materials), except that the limitation on mercury content in alkaline-manganese button cells shall be 25 milligrams of mercury per button cell. 

The cell voltage is 1.5 V. The modem type is the alkaline manganese battery but the classical cell is still on the market. 

A number of batteries are based on modifications of the technology or the substitution of electrode reactions into either the Ni/Cd or Leclanchd cells the changes usually improve one characteristic of importance to a particular duty but usually only at an increased cost. In an alkaline manganese battery, the cathode is manganese dioxide and graphite in the form of compressed tablets, and the electrolyte is strongly alkaline. The cell reaction is... 

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