Page 63 - Handbook of Battery Materials

2.2 Alkaline-Manganese Batteries 29

Zinc powder is packed inside the separator together with the electrolyte solution
and a gelling agent. An anode collector is inserted into the zinc powder. The battery
is hermetically sealed, which contributes to its good shelf life.
Figure 2.2 shows a comparison of the discharge characteristics between
alkaline-manganese batteries and Leclanch´ e batteries. The capacity of the
alkaline-manganese batteries is about three times that of the Leclanch´ e 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

1.6
Alkaline-manganese battery
Leclanche battery
Cell voltage / V 1.2
1.4

1.0

0.8

0 2 4 6 8 10 12 14 16 18
Discharge time / hr
Figure 2.2 Comparison between the discharge character-
istics of alkaline-manganese and Leclanch´ e batteries (load
◦
7.5 ; temperature 20 C).

130
Internal cell impedance / mΩ 110
120

100

90

80

0 0.1 0.2 0.3 0.4 0.5
Additives content / wt%

Figure 2.3 Variation of internal impedance of
alkaline-manganese cells with the additives content of the
zinc powder: , Hg additive: • , In additive.