METHOD OF MANUFACTURING A BATTERY

METHODE DE FABRICATION D'UNE PILE

English Abstract

Title: A Method of Manufacturing a Battery
A b s t r a c t
A method of manufacturing a flat cell comprising a
zinc anode, an alkaline electrolyte, and a cathode in the
form of a briquette of manganese dioxide-carbon being in
contact with a metal terminal. According to the invention
the briquette of manganese dioxide-carbon is secured to the
negative metal terminal through squeezing along two oppos-
ing and bent flaps of the metal terminal. In this manner a
satisfactory contact between the briquette of manganese di=
oxide-carbon and the metal terminal is provided at the same
time as a battery comprising several cells is suited for
mass production, said briquette of manganese dioxide-carbon
may be introduced from the side of the terminal plate bent
along two opposing edges. The terminal plate need only be
bent slightly more than 90°.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of manufacturing a battery comprising
flat cells piled on each other and including a zinc anode,
an alkaline electrolyte, and a cathode in the form of a
briquette of manganese dioxide-carbon, said briquette being
in contact with a metal terminal, characterized by the
briquette (1) of manganese dioxide carbon being secured to
the negative metal terminal (2) through squeezing between
two opposing plane edges of the terminal, said edges being
bent slightly more than 90°,
2. A method as claimed in claim 1, characterized
by the briquettes (1) of manganese dioxide-carbon being
slightly narrower than the metal terminal (2).
3. A method as claimed in claim 2, characterized
by the briquettes 51) of manganese dioxide-carbon being
0.06-0.08 mm narrower than the metal terminal (2).
4. A method as claimed in claim 1, characterized
by the terminal (2) being bent 1-3° inwards along the two
opposing edges.
-5-

Description

~ ~ ~5~3~
The inventlon relates to a method of manufacturing a
battery comprising flat cells piled on each other and including
a zinc anode, an alkaline electrolyte, and a ca-thode in the
form of a briquette of manganese dioxide-carbon, said briquette
being in contact ~-~ith a metal terminal.
The known 9V ba-tteries of a height of about ~0 mm
comprise a plurality of preferably long and narrow cylindrical
members. These members are rather difEicult to manufacture,
i.a. the scrapping percentage is rather highO In addition,
the major portion of the volume is not utilized and the
dimensions are subject to limits.
Flat cells have therefore been introduced, which are
piled on each other, cf. for instance Danish patent application
No. 531~/78, publlshed May 2~, l9i30. In this manner a 28~
higher utilization of the volume is obtained. Each cell is
encased in a plastic cup. However, a particular problem exists
in producing a satisfactory contact between the briquette of
mangane~e dioxide-carbon (the cethcde mass) and the m~tal
terminal in question.
According to the invention it is shown how it is
possible in a simple manner to produce a satisfactory contact
between the briquette of manganese dioxide-carbon and the
metal terminal, and this object is according to the invention
obtained by the briquette of manganese dioxide~carbon
being secured to the negative metal terminal through
squeezing along the edges of said metal terminal, preferably
along two opposing edges. In this manner the battery
is simultaneously suited for mass production since the bri-
mg/ ~- - 2 -

3~
quette of manganese dioxide-carbon then may be clisplaced
from the side of the terminal plate hent along two opposing
edges. The terminal plate need only be bent slightly more,
preferably 1~3, than 9o along two opposin~ edges.
In order to -Eacilitate the introduction fxom -the side
of the briquettes of manganese dioxide-carbon, said bri-
quettes are pre~erably rounded a-t the corners.
~ince the briquettes of manganese dioxide-carbon must
be able to extend, they are about 0.06-0.08 mm narrower
than the metal terminal at their introduction.
The invention will be described below with reference
to the accompanying drawing, in which
Fig. l illustrates part of a battery, whereby a lead-
in to a metal terminal appears, said metal terminal being
in contact with a briquette of manganese dioxide-carbon,
and
Fig. 2 illustrates the metal terminal.
The alkaline battery illustrated in Fig. l comprises a
plurality of flat cells piled on each other. Each cell com-
prises a zinc anode, an alkaline electrolyte, and a cathodein the form of a briquette l of manganese dioxide-carbon.
The briquette of manganese dioxide-carbon is in contact with
a metal terminal 2. A satisfactory contact between the bri-
quette l of manganese dioxide-carbon and the metal terminal
2 must~ however, be provided since this con-tact determines
the short-circuit current. By a quadrangular terminal with
. . .
flaps along all four edges, said flaps would curve outwards
and involve an insufficient electric connection. According

to the inven-tion a bent me-tal part is used, cf. Fig. 2,
comprising flaps along two opposing edges, said flaps fac
ing about 1-3 inwards. In this manner a sufficiently good
squeezing of the briquette 1 of manganese dioxide-carbon is
obtained. The terminal 2 must, of course, be of a suffi-
ciently resilient material such as nickel-iron. As a result
a short-clrcuit current of 3-5 A is obtained. The previous
round cells were not encumbered with this problem since the
electrode mass in question was introduced under a pressure
providing the necessary contact, and since a cylindrical
member is able to receive the pressure in question without
damaging the contact.
The method according to the invention is furthermore
suited for mass production since the terminal body is sym-
metrical and the briquettes of manganese dioxide-carbon may
be introduced from the side when they are rounded at the
corners.
The terminal is op-tionally provided with an additional
flap 4, thereby providing a predetermined contact at the
bottom surface. The briquettes are of a width of about
0.06-0.08 mm smaller than the terminal recognizing that the
briquettes extend slightly when tensions are released by
addition of electrolyte. According to an embodiment the ter-
minal is of a heigh-t of 2.7 mm, a length of 17.5 mm, and a
width of 13.08 mm. The thickness of the material is about
0.1-0.3 mm.