Linden D., Reddy T.B. (eds.) Handbook of batteries

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10.10 CHAPTER TEN

conductive coatings containing carbon may be placed on the surface. Nickel plating may

also be present on the outside surface of the container, either for contact purposes or for

appearance.

The seal is typically a plastic material, such as nylon or polypropylene, combined with

some metal parts, including the anode collector, to make a seat assembly. It closes off the

open end of the cylindrical can, preventing leakage of electrolyte from the cell, and providing

electrical insulation between the cathode collector (can) and the anode collector contact.

The cylindrical alkaline cell has some additional parts, collectively referred to as ﬁnish.

There usually are metal pieces at each end for positive and negative contact. These may be

nickel- or tin-plated for appearance and corrosion resistance. There may be a metal jacket

around the cell, with a printed label on it. In many recent designs the ﬁnish is just a thin

plastic jacket or printed label. In the latter type of cell, the use of the thin plastic allows the

cell container to be made slightly larger in diameter, which results in a signiﬁcant increase

in cell capacity.

Miniature Cell. The container, seal, and ﬁnish materials for the miniature alkaline-

manganese dioxide button cell are essentially the same as those for other miniature cells.

The can (container and cathode collector) is made of mild steel plated on both sides with

nickel. The seat is a thin plastic gasket. The anode cup makes up the rest of the exterior of

the cell. The outer surfaces of the can and anode cup are highly ﬁnished, with manufacturer

identiﬁcation and cell number inscribed on the can. No additional ﬁnish is needed.

10.4 CONSTRUCTION

10.4.1 Cylindrical Conﬁguration

Figure 10.2 shows the construction of typical cylindrical alkaline-manganese dioxide batter-

ies from two manufacturers. Figure 10.3 illustrates the process for assembling the battery. A

cylindrical steel can is the container for the cell. It also serves as the cathode current collector.

The cathode, a compressed mixture of manganese dioxide, carbon, and possibly other ad-

ditives, is positioned inside the can in the form of a hollow cylinder in close contact with

the can inner surface. The cathode can be formed by directly molding it in the can. Alter-

natively, rings of cathode material can be formed outside the cell and then pushed into the

can. Inside the hollow center of the cathode are placed layers of separator material. Inside

of that is the anode, with a metal collector contacting it, and making connection through a

plastic seal to the negative terminal of the cell. The cell has top and bottom covers and a

metal or plastic jacket applied. The covers serve a dual purpose. Besides providing a dec-

orative and corrosion-resistant ﬁnish, they also provide for the proper polarity of the battery.

This is necessary because the cylindrical alkaline manganese battery is used as a direct

replacement for Leclanche´ batteries. Leclanche´ batteries have a ﬂat contact on the negative

(zinc can) end, and a button contact on the positive end to accommodate the carbon rod

used as current collector. The cylindrical alkaline-manganese dioxide cell is built ‘‘inside-

out’’ in relation to the Leclanche´ cell, with the cell container as the positive current collector

and the end of the negative collector protruding from the center of the seal. Therefore to

give it an external form similar to the Leclanche´ battery, the cylindrical alkaline battery must

use a ﬂat cover to contact the terminus of the negative collector, and a bottom cover con-

taining the Leclanche´ positive protrusion in contact with the bottom of the can. (Some

manufacturers mold the protrusion into the can itself, and thus do not need the bottom cover.)

ALKALINE-MANGANESE DIOXIDE BATTERIES 10.11

METALIZED

CAN-STEEL

PLASTIC FILM LABEL

PLATED STEEL

WATER

POTASSIUM

HYDROXIDE /

ELECTROLYTE-

POSITIVE COVER-

BRASS PIN

STEEL

INNER CELL COVER-

SEAL - NYLON

NEGATIVE COVER-

CURRENT COLLECTOR

POWDERED ZINC

PLATED STEEL

CATHODE-

MANGANESE

CARBON

DIOXIDE,

NON-WOVEN

SEPARATOR-

FABRIC

METAL

WASHER

METAL SPUR

ANODE-

(a)

(b)

FIGURE 10.2 Cross section of cylindrical alkaline-

manganese dioxide batteries. [(a) From Eveready Battery En-

gineering Data.

(b) From Duracell Technical Bulletin.

]

10.12 CHAPTER TEN

FIGURE 10.3 Assembly process for AA-size cylindrical alkaline-manganese dioxide battery. (Courtesy

of Eveready Battery Company.)

10.4.2 Button Conﬁguration

The construction of the miniature alkaline-manganese dioxide cell is shown in Fig. 10.4. It

is essentially the same as the construction of other miniature alkaline cells. There are a

bottom cup with a cathode pellet in it, an anode cup containing the anode mix, one or more

round disks of separator material between them, and a plastic seal that is compressed between

the bottom cup and the anode cup to prevent leakage.

FIGURE 10.4 Cross section of miniature alkaline-manganese dioxide battery.

(From Eveready Battery Engineering Data.

)

ALKALINE-MANGANESE DIOXIDE BATTERIES 10.13

10.5 PERFORMANCE CHARACTERISTICS

10.5.1 General Characteristics, Comparison with Leclanche´ Batteries

Alkaline-manganese dioxide batteries have a relatively high theoretical capacity, considerably

higher than Leclanche´ batteries of the same size. There are several reasons for this. The

alkaline-manganese dioxide cell uses manganese dioxide of much higher purity and activity

than is used in most Leclanche´ cells. Moreover, the alkaline-manganese dioxide cell can

function with a very dense cathode, which contains only a small amount of electrolyte.

Furthermore the space taken up by other cell components (separator, current collectors, and

so on) is minimized.

In addition to having a high input capacity, these batteries use that capacity very efﬁ-

ciently. The KOH electrolyte has a very high conductivity, and the zinc anode is in the form

of a high-area powder (compared to the low-area zinc can used in the Leclanche´ cell).

Consequently the internal resistance of the battery is very low at the beginning of discharge

and remains quite low up to the end of its service life (see Sec. 10.5.4).

Alkaline-manganese dioxide batteries perform better than Leclanche´ batteries under a

wide range of conditions. Figure 10.5a compares the discharge curve for an alkaline-

manganese dioxide battery with that for a Leclanche´ battery under a single light-drain con-

tinuous discharge condition. In this case both types of batteries function efﬁciently, delivering

a signiﬁcant part of their theoretical capacity. The alkaline-manganese battery outperforms

the Leclanche´ battery simply because of its higher theoretical capacity. Figure 10.5b shows

a similar comparison of an alkaline-manganese dioxide battery and a Leclanche´ battery under

heavy-drain continuous discharge conditions. Again, the alkaline-manganese dioxide battery

outperforms the Leclanche´ battery, but this time the difference is much larger. The alkaline-

manganese dioxide battery still functions quite efﬁciently due to its superior high-rate ca-

pability, but the Leclanche´ battery is unable to deliver more than a fraction of its theoretical

capacity. Other comparisons of these two types of cells are covered in Chap. 7.

10.14 CHAPTER TEN

Alkaline

Carbon Zinc

2400

2000

1600

800

Service (Hours)

(a)

1200

1.7

1.5

1.1

0.9

Closed Circuit Voltage

1.3

400

0.7

Alkaline

1.6

10 15

Closed Circuit Voltage

0.6

0.8

1.0

1.2

1.4

Carbon Zinc

Service (Hours)

(b)

FIGURE 10.5 Performance comparison of D-size alkaline-manganese dioxide and

zinc-carbon batteries. (a) Typical light drain test (30 mA continuous test at 20⬚C).

(b) Typical heavy drain test (500 mA continuous test at 20⬚C). (Courtesy of Eveready

Battery Company.)

ALKALINE-MANGANESE DIOXIDE BATTERIES 10.15

TABLE 10.7 Estimated Average Service at 21⬚C for an AA-Size Alkaline-Manganese Dioxide

Battery

Schedule

Typical

drains at

1.2 V,

Load,

⍀

Cutoff voltage, V

0.75 0.8 0.9 1.0 1.1 1.2 1.3

Hours

24 h /d 0.8 1500 3300 3200 3100 2400 2100 1800 1200

24 h /d 8 150 325 320 310 240 210 180 138

8 h /d 8 150 325 320 310 240 210 180 138

2 h /d 8 150 330 325 310 240 210 180 138

24 h /d 80 15 33 32 28 24 20 13 5

8 h /d 80 15 33 32 28 24 21 14 5

2 h /d 80 15 34 32 28 24 21 15 7

Minutes

24 h /d 800 1.5 120 115 86 54 25 12 3

10.5.2 Discharge Proﬁle

The voltage proﬁles for the cylindrical and button alkaline-manganese dioxide batteries are

similar. The voltage starts above 1.5 V and decreases gradually during discharge. This occurs

because of the nature of the homogeneous-phase discharge of manganese dioxide, discussed

in Sec. 10.2. Figure 10.5 illustrates the sloping discharge characteristic of the alkaline-

manganese dioxide battery but that it is ﬂatter than that of the zinc-carbon cell. While not

necessarily an advantageous characteristic, most devices that use cylindrical alkaline-

manganese dioxide batteries at low to moderate drains (radios, ﬂashlights, toys, etc.) are

generally tolerant of this discharge characteristic. The sloping discharge can also be advan-

tageous because the gradual decrease in voltage gives the user advance warning of when the

battery is nearing the end of its useful life.

Other types of applications and devices that use miniature alkaline batteries are often less

tolerant of a sloping discharge proﬁle. Many devices are designed for a particular type of

battery, such as zinc/silver oxide. These devices may not function properly when used with

miniature alkaline-manganese dioxide batteries which have a sloping discharge proﬁle. But

for those devices that will tolerate the voltage proﬁle of the alkaline-manganese dioxide

battery, it can provide an economical source of power.

Tables 10.7 and 10.8 present typical service for a particular size, the AA alkaline-

manganese dioxide battery, under various resistive loads and discharge schedules. Discharge

curves for the AA-size alkaline-manganese dioxide battery under continuous resistive dis-

charge conditions at 20

⬚C are shown in Fig. 10.6. The service to several cutoff voltages as

a function of the resistive load is summarized in Fig. 10.7.

Similar curves for constant-current discharges are presented in Fig. 10.8, which shows

the discharge curves at rates ranging from the C/3 to C /250. Figure 10.9 shows the hours

of service delivered to various cutoff voltages over a range of discharge currents. Figure

10.10 shows the capacity service hours of the AA-size and D-size batteries as a function of

the constant-current load to various cutoff voltages. The midpoint voltages for these dis-

charges are plotted in Fig. 10.11.

10.16 CHAPTER TEN

TABLE 10.8 Estimated Average Service at 21⬚C for Simulated Application Tests for an AA-Size

Alkaline-Manganese Dioxide Battery

Schedule

Typical drains at

1.2 V, mA

Load,

⍀

Cutoff voltage, V

0.75 0.8 0.9 1.0

Hours

Radio, 4 h /d 16 75 169 167 155 125

Calculator, 1 h / d 80 15 33 29 26 21

Cassette, 1 h / d 120 10 21 19 17 14

Minutes

Camera, 4 min / 15 min, 8 h/ d, 16 h rest 250 mA constant

current

368

Minutes

Portable light, 4 min /h, 8 h/ d, 16 h rest 308 3.9 404 372 338 292

Toy, continuous 308 3.9 425 399 339 273

Compact disk / TV, 1 h /d 308 3.9 446 404 348 282

Pulses

Pulse 15 s /min, 24 h / d 667 1.8 584

FIGURE 10.6 Typical discharge performance characteristics for AA-size

alkaline-manganese dioxide battery. (a) continuous moderate-drain discharge

at 20⬚C. (b) Continuous heavy-drain discharge at 21⬚C. (Courtesy of Eveready

Battery Company.)

ALKALINE-MANGANESE DIOXIDE BATTERIES 10.17

FIGURE 10.7 Typical continuous discharge service to various cutoff

voltages at various loads for AA-size alkaline-manganese dioxide battery

at 21⬚C. (Courtesy of Eveready Battery Company.)

FIGURE 10.8 Typical constant-current discharge curves at 20⬚C for an AA-size

alkaline-manganese dioxide battery; voltage vs. percent of capacity at various dis-

charge rates. (Courtesy of Duracell, Inc.)

10.18 CHAPTER TEN

FIGURE 10.9 Typical constant-current discharge performance at 20⬚Cof

typical zinc-alkaline batteries; (a) AA-size battery. (b) D-size battery; service

to various cutoff voltages vs. discharge current. (Courtesy of Duracell, Inc.)

ALKALINE-MANGANESE DIOXIDE BATTERIES 10.19

FIGURE 10.10 Capacity of typical AA-size alkaline battery

on constant-current discharge at 20⬚C vs. current drain for var-

ious end-point voltages.

FIGURE 10.11 Typical midpoint voltages during discharge of a typical AA-size

alkaline battery at various discharge currents at 20⬚C, 0.8-V end voltage.