Description
BATTERY HAVING ENHANCED ELECTRICAL INSULATION
CAPABILITY
Technical Field
[ 1 ] The present invention relates to a battery having enhanced electrical insulation ca-
pability, and more particularly, to a battery wherein an insulator tape is attached to the
boundary of a cathode active-material coating layer at a position where an anode
active-material coating layer faces a cathode uncoated part where no cathode active-
material coating layer is present, achieving enhanced electrical insulation capability
and consequential safety of the battery.
[2]
Background Art
[3] Conventionally, differently from a primary battery having no charge ability, a
rechargeable secondary battery having charge and discharge characteristics is actively
under study with the development of advanced technologies including digital cameras,
cellular phones, laptop computers, hybrid cars, etc. Examples of the secondary battery
include a nickel-cadmium battery, nickel-metal hydride battery, nickel-hydrogen
battery, a lithium secondary battery, etc.
[4] Of the above-mentioned secondary batteries, a lithium secondary battery has an
actuation voltage of 3.6V or more. The lithium secondary battery may be utilized as a
power source for portable electronic appliances, or may be utilized in high-power
hybrid cars when a plurality of lithium secondary batteries are connected in series.
Since the lithium secondary battery has a higher actuation voltage three times that of
the nickel-cadmium battery or nickel-metal hydride battery and also, has superior
energy density per unit weight, the use of the lithium secondary battery is rapidly in-
creasing.
[5] At present, a lithium ion battery has been fabricated, wherein a cathode and an anode,
which are insulated by a separator interposed therebetween, are wound into a
cylindrical or prismatic electrode assembly, and after the resulting electrode assembly
is inserted into a metal can, an electrolyte is injected into the metal can. As the metal
can is sealed, the fabrication of the lithium ion battery is completed.
[6] More particularly, a conventional lithium ion battery includes a cathode in which a
cathode active-material coating layer is provided on one surface or both surfaces of a
cathode collector, and an anode in which an anode active-material coating layer is
provided on one surface or both surfaces of an anode collector, the cathode and anode
being wound with a plurality of separators interposed therebetween.

[7] In the case where active-material coating layers are provided on both surfaces of an
electrode collector, the active-material coating layer provided on one surface of the
electrode collector is generally shorter than the active-material coating layer provided
on the other surface of the electrode collector. Typically, it is desirable that a length
and width of an anode be longer than a length and width of a cathode, to prevent ex-
traction of lithium ions from the cathode.
[8] FIG. 1 is a sectional view of a conventional battery, and FIG. 2 illustrates a "jelly-
roll" configuration of the wound battery. Considering the configuration of the con-
ventional battery in detail with reference to the drawings, the battery includes a
cathode in which cathode active-material coating layers 20a and 20b are provided on at
least one surface of a cathode collector 10, an anode in which anode active-material
coating layers 40a and 40b are provided on at least one surface of an anode collector
30, and a plurality of separators 50a and 50b interposed between the cathode and the
anode.
[9] At least one of a winding beginning portion and winding ending portion of the
cathode collector 10 or anode collector 30 contains a cathode uncoated part 10' or
anode uncoated part 30' where no electrode active-material coating layer is present.
These uncoated parts 10' and 30' are provided with electrode leads 60 and 70 to be
connected to exterior terminals. Both the electrode leads, i.e. a cathode lead 60 and an
anode lead 70 are arranged in the same direction.
[10] When the cathode active-material coating layer 20a comes into contact with the
anode with the separator interposed therebetween, the cathode active-material coating
layer 20a must overlap the facing anode active-material coating layer 40b (in other
words, must have a smaller area than that of the anode active-material coating layer
40b), in consideration of a winding deviation and positional change caused upon
charge and discharge of the battery. Under this condition, the boundary between the
cathode active-material coating layer and the cathode uncoated part 10' comes across
the anode active-material coating layer 40b. This causes micro-holes or shrinkage and
damages to other functions of the facing separator 50, resulting in significant heat
emission upon contact between the anode active-material coating layer 40b and the
cathode uncoated part 10'.
[11] Meanwhile, when the anode and cathode active-material coating layer come into
contact with each other under the occurrence of short circuit, there exist a negligible
short circuit current and heat emission because of a high electric resistance of the
cathode active-material coating layer. However, when the anode comes into contact
with the cathode uncoated part (i.e. a part of the cathode collector where no cathode
active-material coating layer is present), an insufficient electric resistance causes a
serious short circuit current and heat emission which act as dangerous factors sig-

nificantly deteriorating safety of the battery.
[12] To solve the above-described problems, conventionally, a method for providing in-
sulators 90a, 90b, 90c and 90d at the boundary of the cathode active-material coating
layer for preventing short circuit in facing region between the cathode uncoated part
and the anode has been adopted.
[ 13] Referring to FIG. 2 illustrating the jelly-roll wound configuration of the battery
shown in FIG. 1, front and rear sides of the cathode lead 60 face the anode uncoated
part or the anode active-material coating layer, respectively, with only one layer of
separator interposed merebetween. Therefore, either side of the cathode lead 60 has a
necessity for an additional insulator for the purpose of preventing short circuit.
[14] Further, since a beginning portion or ending portion of the cathode active-material
coating layer faces the anode active-material coating layer with only one layer of
separator interposed therebetween, it is necessary to provide an insulator therebetween
for the purpose of preventing short circuit.
[151 With respect to the anode lead 70, it comes into contact, at opposite sides thereof,
with the anode with six layers of separators and two layers of separators interposed
therebetween, respectively. Therefore, there is no necessity for an additional insulator.
Similar to the anode lead 70, both surfaces of a winding beginning portion of the anode
come into contact with another region of the anode with six layers of separators and
two layers of separators interposed therebetween, respectively, eliminating a necessity
for an additional insulator.
[16] However, a beginning portion and distal end of the anode coating layer faces the
cathode uncoated part or cathode active-material coating layer with only one layer of
the separator interposed therebetween and therefore, it is necessary to provide an ad-
ditional insulator due to a risk of short circuit.
[17]
Disclosure of Invention
Technical Problem
[18] Therefore, the present invention has been made to solve a problem of short circuit
caused when a non-coating part of one electrode where no active material is present
faces the other electrode.
[19] To prevent short circuit between one electrode and the other electrode facing each
other and consequential deterioration in electrical insulation capability, the present
invention proposes that a cathode lead and anode lead are arranged in opposite di-
rections, rather than being arranged in the same direction, to prevent a cathode
uncoated part from facing an anode, and that a cathode is not provided, at a side
thereof opposite to the cathode lead, with the cathode uncoated part as a non-coating

part containing no cathode active-material coating layer, so as to eliminate a risk of
short circuit caused when the cathode uncoated part faces the anode. When the cathode
uncoated part is provided as occasion demands, the present invention proposes to
provide an additional insulator tape at the cathode uncoated part. Furthermore, in con-
sideration of a risk of short circuit caused when only one surface of the cathode is
coated with a cathode active-material and a non-coating part provided at the other
surface of the cathode faces an anode active-material coating layer, an insulator tape is
additionally attached to the boundary of the cathode active-material coating layer.
[20] Accordingly, it is an object of the present invention to provide a battery having
enhanced electrical insulation capability.
[21]
Technical Solution
[22] In accordance with the present invention, the above and other objects can be ac-
complished by the provision of a battery including: a cathode having a cathode active-
material coating layer provided on at least one surface of a cathode collector; and an
anode having an anode active-material coating layer provided on at least one surface of
an anode collector, the cathode and anode being wound to face each other with a
separator interposed therebetween, wherein both upper and lower surfaces of the
cathode collector are provided with cathode active-material coating layers so as not to
provide a cathode uncoated part at a winding beginning portion of the cathode, and the
cathode uncoated part for installation of a cathode lead is provided only at a winding
ending portion of the cathode, and wherein an insulator tape is attached to the
boundary of the cathode active-material coating layer facing the anode at the winding
ending portion of the cathode.
[23]
Advantageous Effects
[24] In a battery designed such that a cathode is not provided on at least one side thereof
with a cathode uncoated part, it is possible to eliminate a risk of short circuit between
the cathode and an anode arranged facing the cathode. According to the present
invention, even if the cathode uncoated part is provided as occasion demands, an
insulator tape is provided at the cathode uncoated part, so as to eliminate a risk of short
circuit due to the cathode uncoated part. Further, according to the present invention, an
insulator tape is attached to the boundary of a cathode active-material coating layer at a
position where an anode active-material coating layer faces a non-coating part not
containing the cathode active-material coating layer, achieving enhanced electrical in-
sulation capability and safety of the battery.

Brief Description of Drawings
[26] The above and other objects, features, and other advantages of the present invention
will be more clearly understood from the following detailed description taken in con-
junction with the accompanying drawings, in which:
[27] FIGS. 1 and 2 are views illustrating a configuration of a conventional battery and a
jelly-roll wound configuration of the battery;
[28] FIGS. 3 and 4 are views illustrating a configuration of a battery and a jelly-roll
wound configuration of the battery according to a first embodiment of the present
invention;
[29] FIGS. 5 and 6 are views illustrating a configuration of a battery and a jelly-roll
wound configuration of the battery according to a second embodiment of the present
invention;
[30] FIGS. 7 and 8 are views illustrating a configuration of a battery and a jelly-roll
wound configuration of the battery according to a third embodiment of the present
invention; and
[31] FIGS. 9 and 10 are views illustrating a configuration of a battery and a jelly-roll
wound configuration of the battery according to a fourth embodiment of the present
invention.
[32]
Best Mode for Carrying out the Invention
[33] Hereinafter, the present invention will be described in more detail with reference to
the accompanying drawings.
[34] Referring to FIG. 3 illustrating an electrode configuration according to the present
invention, a cathode having a cathode active-material coating layer provided on at least
one surface of a cathode collector, and an anode having an anode active-material
coating layer provided on at least one surface of an anode collector are wound to face
each other with a separator interposed therebetween.
[35] The cathode includes cathode active-material coating layers 120a and 120b on both
upper and lower surfaces of a cathode collector 110, respectively. The cathode
collector 110 is provided, in at least one direction thereof, preferably, at a winding
ending portion thereof, with a cathode uncoated part 110' for installation of a cathode
lead 160, the cathode uncoated part 110' being a non-coating part where no cathode
active-material coating layer is present. With respect to the other direction of the
cathode collector 110 not containing the cathode lead 160, there exists no cathode
uncoated part in which at least one surface of the cathode collector 110 is not coated
with a cathode active-material.
[36] Specifically, since the cathode uncoated part may act as a dangerous factor to sig-

nificantly deteriorate safety of the battery due to short circuit current and high heat
emission caused as an anode comes into contact with the cathode uncoated part,
omission of the cathode uncoated part has the effect of preventing short circuit. The
above-described configuration of the cathode may be realized via, for example, a
block-cutting method, or a two-step cutting method wherein a cathode uncoated part
not containing the cathode active-material coating layer is cut once and thereafter, the
cathode active-material coating layer is cut.
[37] The anode according to the present invention includes anode active-material coating
layers 140a and 140b on both upper and lower surfaces of an anode collector 130, re-
spectively. At least one side, i.e. a winding beginning portion or winding ending
portion of the anode collector 130 is defined with an anode uncoated part 130' not
containing the anode active-material coating layers 140a and 140b. An anode lead 170
to be connected to an exterior terminal is connected to the anode uncoated part 130'.
[38] In the present invention, the cathode lead 160 and anode lead 170 are arranged in
opposite directions, rather than being arranged in the same direction as described with
relation to the prior art. This arrangement is proposed to prevent short circuit caused
when the cathode lead and anode lead are arranged in the same direction to face each
other with one layer of separator interposed therebetween. When the cathode lead 160
and anode lead 170 are arranged in opposite directions according to the present
invention, the cathode lead 160 is located at a winding distal end to face the cathode,
eliminating a risk of short circuit.
[39] The separator is positioned to extend lengthwise beyond an ending portion of the
anode, to prevent short circuit between the cathode and the anode even if the separator
undergoes shrinkage upon receiving heat. Preferably, the separator further extends
from the ending portion of the anode by a length of at least 5mm or more.
[40] In the above-described configuration of the present invention as can be seen from the
configuration shown in FIG. 3, with respect to a winding beginning portion of the
cathode collector 110 where the cathode uncoated part, containing no cathode active-
material coating layer, is not present, the anode active-material coating layers 140a and
140b on the upper and lower surfaces of the anode collector 130 come into contact
with the cathode active-material coating layers 120a and 120b provided on the upper
and lower surfaces of the cathode collector 110 with separators 150a and 150b in-
terposed therebetween, having no risk of short circuit between the cathode and the
anode.
[41] With respect to a winding ending portion of the anode collector 130, the anode
active-material coating layer 140a provided on the upper surface of the anode collector
130 comes into indirect contact with the boundary of the cathode active-material
coating layer 120b provided on the lower surface of the cathode collector 110 where

the cathode lead 160 is installed with the separator 150a interposed therebetween. In
this case, an insulator tape 190b is attached to the boundary of the cathode active-
material coating layer 120b, so as to prevent short circuit between the cathode
uncoated part 110' not containing the cathode active-material coating layer and the
anode active-material coating layer 140a.
[42] In addition, with respect to the winding ending portion of the anode collector 130, the
anode active-material coating layer 140b provided on the lower surface of the anode
collector 130 comes into indirect contact with the boundary of the cathode active-
material coating layer 120a on the upper surface of the cathode collector 110 where the
cathode lead 160 is installed with the separator 150b interposed therebetween. In this
case, an insulator tape 190a is attached to the boundary of the cathode active-material
coating layer 120b, so as to prevent the anode active-material coating layer 140b from
coming into contact with a non-coating part not containing the cathode active-material
coating layer.
[43] Hereinafter, exemplary embodiments of the present invention will be described in
more detail with reference to the accompanying drawings, wherein the cathode, anode
and separator are wound on a winding mandrel. Of course, it will be appreciated that
the present invention is not limited to these embodiments.
[44] FIGS. 3 and 4 are, respectively, a sectional view of a battery and a view illustrating a
jelly-roll wound configuration of the battery according to a first embodiment of the
present invention.
[45] Referring to FIG. 4 illustrating the jelly-roll wound configuration of the battery, a
cathode of the present embodiment does not contain a cathode uncoated part at a
winding beginning portion thereof, and upon winding, cathode active-material coating
layers on upper and lower surfaces of a cathode collector come into contact with anode
active-material coating layers, respectively, with one layer of separator interposed
therebetween. The winding beginning portion of the cathode may be realized via, for
example, a block-cutting method, or a two-step cutting method wherein the cathode
uncoated part not containing the cathode active-material coating layer is cut once and
thereafter, the cathode active-material coating layer is cut.
[46] A cut face of an anode uncoated part 130' provided at the winding beginning portion
of the anode is provided at opposite sides thereof with several layers of separators,
achieving enhanced safety against burrs on the cut face. Further, with respect to the
winding ending portion of the anode, although either side of a cut face of the anode
uncoated part faces the cathode with only one layer of separator interposed
therebetween, provision of the insulator tapes 190a and 190b on the boundaries of the
cathode active-material coating layers can improve safety of the battery against burrs
present on the cut face.

[47] In the above-described first embodiment of the present invention as shown in FIGS.
3 and 4, the insulator tapes 190a and 190b are attached to the boundaries of the cathode
active-material coating layers provided on the upper and lower surfaces of the cathode
collector at the ending portion of the cathode, preventing short circuit between the
anode active-material coating layer and a facing non-coating part not containing the
cathode active-material coating layer.
[48] Preferably, the insulator tapes 190a and 190b are attached to the boundaries of the
cathode active-material coating layers during an electrode winding process or during
fabrication of a large-width electrode.
[49] In the present embodiment, the cathode lead 160 and the anode lead 170 are arranged
in opposite directions, rather than being arranged in the same direction. In particular,
the cathode collector is not provided at an opposite side of the cathode lead 160 with
the cathode uncoated part, so as to prevent short circuit with the anode.
[501 A separator 150 is positioned to further extend from the ending portion of the anode
by a length of at least 5mm or more. With this configuration, it is possible to prevent
the anode active-material coating layer from being exposed to the outside even if the
separator undergoes heat shrinkage.
[51 ] FIGS. 5 and 6 illustrate an exemplary second embodiment of the present invention.
As compared to the previously described first embodiment, in the second embodiment
of the present invention, cathode active-material coating layers 220a' and 220b' are
further provided on upper and lower surfaces of a distal end of a cathode uncoated part
where a cathode lead is installed.
[52] Similar to the previously described first embodiment, a cathode does not contain a
cathode uncoated part at a winding beginning portion thereof. As shown in FIG. 6,
cathode active-material coating layers on the upper and lower surfaces of the cathode
collector at a winding beginning portion of the cathode come into contact with anode
active-material coating layers, respectively, with one layer of separator interposed
therebetween. A tip end of the cathode may be realized via a one-step cutting method.
[53] With provision of the additional cathode active-material coating layers 220a" and
220b' on the upper and lower surfaces of the distal end of the cathode uncoated part
where a cathode lead 260 is installed, the present embodiment has no necessity for an
insulator tape with respect to the cathode uncoated part.
[54] The cathode lead 260 and an anode lead 270 are arranged in opposite directions,
rather than being arranged in the same direction. In particular, the cathode collector is
not provided at an opposite side of the cathode lead 260 with the cathode uncoated
part, so as to prevent short circuit with the anode.
[55] A separator 250 is positioned to further extend from the ending portion of the anode
by a length of at least 5mm or more(See the Figure 6). With this configuration, it is

possible to prevent the anode active-material coating layer from being exposed to the
outside even if the separator undergoes heat shrinkage.
[56J A cut face of an anode uncoated part 230' provided at a winding beginning portion of
the anode is provided at opposite sides thereof with several layers of separators,
achieving enhanced safety against burrs on the cut face. Further, with respect to a
winding ending portion of the anode, although either side of a cut face of the anode
uncoated part faces the cathode with only one layer of separator interposed
therebetween, insulator tapes 290a and 290b are attached to boundaries of the cathode
active-material coating layers, achieving enhanced safety of the battery against burrs
present on the cut face.
[57] In the above-described second embodiment of the present invention, similar to the
previously described first embodiment, the insulator tapes 290a and 290b are attached
to the boundaries of the cathode active-material coating layers provided on the upper
and lower surfaces of the cathode collector at the ending portion of the cathode,
preventing short circuit between the anode active-material coating layer and a facing
non-coating part not containing the cathode active-material coating layer.
[58] Preferably, the insulator tapes 290a and 290b are attached to the boundaries of the
cathode active-material coating layers during an electrode winding process or during
fabrication of a large-width electrode.
[59] FIGS. 7 and 8 illustrate an exemplary third embodiment of the present invention. As
compared to the previously described second embodiment, the present embodiment
employs an increased number of insulator tapes. Specifically, insulator tapes 390c and
390d are attached to boundaries of cathode active-material coating layers on upper and
lower surfaces of a cathode collector at a tip end of a cathode, and insulator tapes 390a
and 390b are attached to boundaries of the cathode active-material coating layers on
the upper and lower surfaces of the cathode collector at an ending portion of the
cathode. In addition, insulator tapes 390e and 390f are attached to boundaries of
cathode active-material coating layers 320a' and 320b' additionally provided on a distal
end of a cathode uncoated part at the ending portion of the cathode. With provision of
these insulator tapes, it is possible to prevent short circuit caused when the anode
active-material coating layer faces a non-coating part of the cathode not containing the
cathode active-material coating layer.
[60] A cut face of an anode uncoated part 330' provided at the winding beginning portion
of the anode is provided at opposite sides thereof with several layers of separators,
achieving enhanced safety against burrs on the cut face. Further, with respect to the
winding ending portion of the anode, although either side of a cut face of the anode
uncoated part faces the cathode with only one layer of separator interposed
therebetween, provision of the insulator tapes 390a and 390b can improve safety of the

battery against burrs present on the cut face.
[61] A cathode lead 360 and an anode lead 370 are arranged in opposite directions, rather
than being arranged in the same direction. In particular, the cathode collector is not
provided at an opposite side of the cathode lead 360 with the cathode uncoated part, so
as to prevent short circuit with the anode.
[62] A separator 350 is positioned to further extend from the ending portion of the anode
by a length of at least 5mm or more. With this configuration, it is possible to prevent
the anode active-material coating layer from being exposed to the outside even if the
separator undergoes heat shrinkage.
[63] FIGS. 9 and 10 illustrate an exemplary fourth embodiment of the present invention.
In the present embodiment, a cathode collector 410 is provided at both distal ends
thereof with cathode uncoated parts 410' where no cathode active-material coating
layer is present. Accordingly, cathode active-material coating layers begin to extend on
upper and lower surfaces of the cathode collector from positions spaced apart from a
winding beginning portion of the cathode by a predetermined distance. Upon winding,
the winding beginning portion of the cathode comes into indirect contact with an anode
active-material coating layer with one layer of separator interposed therebetween as
shown in FIG. 10. In the present embodiment, to prevent short circuit caused when the
cathode uncoated part faces the anode active-material coating layer, insulator tapes
490c and 490d are additionally attached to boundaries of cathode active-material
coating layers on upper and lower surfaces of the cathode collector at a tip end of the
cathode.
[64] The winding beginning portion of the cathode is formed with a cathode uncoated part
where no cathode active-material coating layer is present via a one-step cutting
method.
[65] To prevent electrical short circuit between the non-coating part not containing the
cathode active-material coating layer and the anode active-material coating layer
facing each other, insulator tapes 490a and 490b are attached to the cathode active-
material coating layers provided on upper and lower surfaces of the cathode collector
at an ending portion of the cathode, and insulator tapes 490e and 490f are attached to
upper and lower surfaces of the cathode uncoated part at a distal end of the cathode
collector where a cathode lead is installed.
[66] A cut face of an anode uncoated part 430' provided at the winding beginning portion
of the anode is provided at opposite sides thereof with several layers of separators,
achieving enhanced safety against burrs on the cut face. Further, with respect to the
winding ending portion of the anode, although either side of a cut face of the anode
uncoated part faces the cathode with only one layer of separator interposed
therebetween, provision of the insulator tapes 490a and 490b on the boundaries of the

cathode active-material coating layers can improve safety of the battery against burrs
present on the cut face.
[67] Preferably, the insulator tapes 490a, 490b, 490c, 490d, 490e and 490f are attached to
the boundaries of the cathode active-material coating layers during an electrode
winding process or during fabrication of a large-width electrode.
[68] A cathode lead 460 and an anode lead 470 are arranged in opposite directions, rather
than being arranged in the same direction. Separators 450a and 450b are positioned to
extend lengthwise beyond a distal end of the anode, in consideration of heat shrinkage
of the separators 450a and 450b.
[69] With the above-described configuration of the battery according to the present
invention, the cut face of the anode uncoated part at a tip end of the anode as a winding
beginning portion is insulated and protected by plural layers of separators interposed
therebetween, and the cut face of the anode uncoated part at a distal end of the anode
as a winding ending portion is protected by insulator tapes attached to the boundaries
of the cathode active-material coating layers, resulting in a secondary battery having
excellent electrical insulation capability.
[70] Although the insulator tapes, used in the respective embodiments of the present
invention, are not limited to special insulator tapes so long as they have excellent
electrical insulation capability, materials having no heat shrinkage up to 200°C are
preferable. Further, using materials having slight shrinkage under the influence of heat
is more preferable to prevent any troubles of a separator interposed between electrodes.
[71] The insulator tapes may be one or more selected from the group consisting of
polyimide tapes, acetate tapes, glass-cloth tapes, polyester tapes, polyphenylenesulfide
(PPS) tapes and polypropylene tapes. Preferably, the insulator tapes are polyethylene
terephthalate tapes.
[72] Preferably, the insulator tapes provided in the battery according to the present
invention have a thickness of 10/µm to 100/µm.
[73] Hereinafter, other constituent elements of the battery according to the present
invention will be described, in particular, with respect to a secondary battery.
[74] The cathode collector according to the present invention may be made of stainless
steel, nickel, aluminum, titanium, or alloys thereof, or may have an aluminum or
stainless steel surface treated with carbon, nickel, titanium, or silver. Of these various
materials, aluminum or aluminum alloy is preferable.
[75] Specific examples of a cathode active-material according to the present invention
may include, but are not limited to; lamellar compounds such as lithium cobalt oxide
(LiCoO2), lithium nickel oxide (LiNiO2), etc., or compounds substituted by one or
more transition metals; lithium manganese oxide represented by chemical formula Li1+X
Mn2-XO4 (where, x is a value of 0~0.33), such as LiMnO3, LiMn2O3, LiMnO2, etc.;

lithium copper oxide (Li2CuO2); LiFe3O4; vanadium oxide, such as LiV3O8, V2O5, Cu2
V2O7, etc.; Ni-site type lithium nickel oxide represented by chemical formula LiNi1-xMx
O2 (where, M is Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x is a value of 0.01~0.3);
lithium manganese composite oxide represented by chemical formula LiMn2-xMxO2
(where, M is Co, Ni, Fe, Cr, Zn or Ta, and x is a value of 0.01~0.1) or Li2Mn3MO8
(where, M is Fe, Co, Ni, Cu or Zn); LiMn2O4 in which Li in chemical formula is sub-
stituted by alkaline earth metal ions; disulfide compounds; Fe2(MoO4)3, etc. Preferably,
the cathode active-material may be lithium cobalt oxide, lithium manganese oxide,
lithium nickel oxide, lithium manganese cobalt nickel oxide, or composites of two or
more thereof.
[76] The anode collector according to the present invention may be made of stainless
steel, nickel, copper, titanium, or alloys thereof, or may have a copper or stainless steel
surface treated with carbon, nickel, titanium, or silver. Of these various materials,
aluminum or aluminum alloy is preferable.
[77] Specific examples of an anode active-material according to the present invention may
include, but are not limited to; carbon and graphite materials, such as natural graphite,
artificial graphite, expanded graphite, carbon fiber, non-graphitizing carbon, carbon
black, carbon nano-tubes, fullerenes, activated carbon, etc.; metals capable of being
alloyed with lithium, such as Al, Si, Sn, Ag, Bi, Mg, Zn, In, Ge, Pb, Pd, Pt, Ti, etc. and
compounds containing these elements; composites of metals and compounds thereof
and carbon and graphite materials; lithium-based nitrides, etc. Preferably, the anode
active-material may be only one or combinations of two or more selected from the
group consisting of crystalline carbon, amorphous carbon, silicon-based active
materials, tin-based active materials, and silicon-carbon-based active materials. In
addition, a conventional binder, conductor, and additive may be added to the anode,
and detailed examples or contents thereof are sufficient if they fulfill conventional
levels.
[78] The binder serves to assist coupling between the active material and the conductor as
well as coupling between the active material and the collector, and may be added at 1
to 50 weight% based on the total weight of electrode compound mixture. Examples of
the binder include polyvinylidenefluoride (PVDF), polyvinylalcohol, carboxymethyl-
cellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose,
polyvinylpyrrolidone, tetrafluoroethylene, polyethelene, polypropylene, ethylene-
propylene-diene polymer (EPDM), sulfonized EPDM, styrene-butadiene rubber, fluoro
rubber, and various copolymers thereof.
[79] The conductor is a component to further improve conductivity of an electrode active
material, and may be added at 1 to 20 weight% based on the total weight of electrode
compound mixture. The conductor may be selected, without particular limitation, from

materials, which have a desired conductivity and do not cause any chemical variation
in the battery. Examples of the conductor may include graphite, such as natural
graphite, artificial graphite, etc.; black matters, such as carbon black, acetylene black,
Ketjen black, channel black, perneis black, lamp black, summer black, etc.; conductive
fiber, such as carbon fiber, metal fiber, etc.; metal powders, such as fluorocarbon,
aluminum, nickel powder, etc.; conductive whisker, such as zinc oxide, potassium
titanate, etc.; conductive metal oxide, such as titanium oxide, etc.; polyphenylene
derivative, etc.
[80] The additive is selectively used to restrict expansion of the anode. The additive is
selected, without particular limitation, from fibrous materials not causing a chemical
variation in the battery. Examples of the additive include olefin-based polymers, such
as polyethylene, polypropylene, etc.; and other fibrous materials, such as glass fiber,
carbon fiber, etc.
[81] The separator, interposed between the cathode and the anode, is an insulating thin-
film having a high ion transmissivity and mechanical strength. Generally, the separator
has ultra-fine pores having a diameter of 0.01µm to 10µm, and a thickness of the
separator is within a range of 5µm to 300µm. For example, the separator may be
composed of chemical-resistant and hydrophobic olefin-based polymers, such as
polypropylene, etc.; sheets or non-woven fabrics made of glass fiber or polyethylene,
etc.; and kraft paper, etc. Representative examples of currently commercially available
separators include Celgard series products (CelgardTM 2400 & 2300) by Hoechest
Celanese Corp., polypropylene separators by Ube Industries Ltd. or Pall RAIMFG
Co., polyethylene-based separators by Tonen or Entek, etc.
[82] As occasion demands, to enhance stability of the battery, a gel polymer electrolyte
may be coated over the separator. Representative examples of gel polymers may
include polyethyleneoxide, polyvinylidenefluoride, polyacrylonitrile, etc. When a solid
electrolyte, such as polymers, etc., is used, the solid electrolyte may also serve as a
separator.
[83] The cathode lead and anode lead are attached, in an electrically conductive manner,
to the cathode and anode via welding, such as laser welding, ultrasonic welding or
resistant welding, or by use of a conductive adhesive. Protective tapes, made of in-
sulating materials, are attached to the electrode leads, to prevent short circuit between
the electrodes.
[84] The present invention provides a prismatic battery obtained as the battery having the
above-described configuration is received in a prismatic battery can together and then,
a non-aqueous electrolyte is added.
[85] The non-aqueous electrolyte contains lithium salt, and consists of a non-aqueous
electrolyte solution and lithium salt. The non-aqueous electrolyte is selected from

among a non-aqueous electrolyte solution, solid electrolyte, inorganic solid electrolyte,
etc.
[86] For example, the non-aqueous electrolyte solution may be an aprotic organic solvent,
such as N-methyl-2-pyrollidinon, propylene carbonate, ethylene carbonate, butylene
carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, gamma-
butyro lactone, 1,2-dimethoxy ethane, 1,2-diethoxy ethane, tetrahydroxy franc,
2-methyl tetrahydrofurane, dimethylsulfoxide, 1,3-dioxolene, 4-methyl-l,3-dioxene,
diethylether, formamide, dimemylformamide, dioxolene, acetonitrile, nitromethane,
methyl formic acid, methyl acetic acid, phosphoric acid triester, trimethoxy methane,
dioxolene derivative, sulfolane, methyl sulfolane, l,3-dimethyl-2-imidasolidinone,
propylene carbonate derivative, tetrahydrofurane derivative, ethers, methyl propionic
acid, ethyl propionic acid, etc.
[87] For example, the organic solid electrolyte may be a polyethylene derivative,
polyethylene oxide derivative, polypropylene oxide derivative, phosphoric acid ester
polymer, polyagitation lysine, polyester sulfide, polyvinylalcohol, poly fluo-
rovinylidene, polymers containing ionic disintegrators, etc.
[881 The inorganic solid electrolyte, for example, may include Li-based nitrides, such as
Li3N, Lil, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4 -
Lil-LiOH, Li3PO4-Li2S-SiS2, etc., halides, sulfates, etc.
[89] The lithium salt is a material sufficiently soluble in the non-aqueous electrolyte and
for example, may be LiCI, LiBr, Lil, LiCIO4, LiBF4, LiB10CI10, LiPF6, LiCF3SO3, LiCF
3CO2, LiAsF6, LiSbF6, LiAICL, CH3SO3Li, CF3SO3Li, LiSCN, LiC(CF3SO2)3, (CF3SO2
)2NLi, chloroboranlithium, low-grade aliphatic carbonic acid lithium, 4-penyl-boric
acid lithium, imides, etc.
[90] For the purpose of enhancing charge and discharge characteristics, fire-retardancy,
etc., for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylene
diamine, n-glyme, hexa phosphoric acid tri amide, nitrobenzene derivative, sulfur,
quinone imine colorant, N-substituted oxasolidinone, N,N-substituted imidasolidine,
ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxy ethanol, trichloro
aluminum, etc. may be added to the non-aqueous electrolyte. As occasion demands, to
endow incombustibility, a halogen containing solvent, such as tetrachlorocarbon, triflu-
oroethylene, etc., may be added to the non-aqueous electrolyte. Further, to improve
high-temperature maintenance characteristics, carbon dioxide gas may be further added
to the non-aqueous electrolyte.
[91] Now, the fabrication of the prismatic lithium battery according to the present
invention will be described in brief. First, an electrode group having an approximately
oval cross section is prepared by winding a cathode and an anode with a separator in-
terposed therebetween, the separator being made of a non-porous polyethylene film

having a thickness of 20/µm. The electrode group is received in a prismatic aluminum
battery can having the bottom and sidewall. The top of the battery can define an
opening and has an approximately square form. Thereafter, an insulator tape to prevent
short circuit between a cathode lead or anode lead and the battery can is prepared and
additionally, insulator tapes are prepared at respective regions having a risk of short
circuit. In the present invention, when an insulator tape is attached to a non-coating
part containing no cathode active-material coating layer which faces an anode active-
material coating layer, the insulator tape may be formed via an insulator tape at-
tachment apparatus in a winding process, or may be attached by a length corresponding
to a width of an electrode during an electrode coating process. Then, a spherical
sealing member in which an anode terminal surrounded by an insulating gasket is
centrally provided is disposed in the opening of the battery can, and the anode lead is
connected to the anode terminal. The cathode lead is connected to a lower surface of
the sealing member. As the sealing member is welded to the periphery of the opening
via laser welding, the opening of the battery can is sealed. Thereafter, a non-aqueous
electrolyte is injected into the battery can through an injection hole perforated in the
sealing member. Finally, as the injection hole is blocked by a plug via welding, the
fabrication of the prismatic lithium secondary battery is completed.
[92] The batteries fabricated according to the first to fourth embodiments and the con-
ventional battery as shown in FIG. 1 were subjected to stability estimation via a hot
box test, and the results of which are shown in the following Table 1. Here, the hot box
test was performed at 150°C for 1 hour.
[93] Table 1
[Table 1]
[Table ]

[94] As can be seen from the results of the above Table 1, the prismatic battery fabricated
according to the present invention has no risk of internal short circuit under any
dangerous environment, achieving considerably enhanced safety of the battery.
[95]
Mode for the Invention

[96] Various embodiments have been described in the best mode for carrying out the
invention.
[97]
Industrial Applicability
[98] The present invention is applicable to a lithium secondary battery for achieving
enhanced electrical insulation capability and consequential safety of the battery.
[99] Although the preferred embodiments of the present invention have been disclosed for
illustrative purposes, those skilled in the art will appreciate that various modifications,
additions and substitutions are possible, without departing from the scope and spirit of
the invention as disclosed in the accompanying drawings.

Claims
[1] A battery comprising: a cathode having a cathode active-material coating layer
provided on at least one surface of a cathode collector; and an anode having an
anode active-material coating layer provided on at least one surface of an anode
collector, the cathode and anode being wound to face each other with a separator
interposed therebetween,
wherein both upper and lower surfaces of the cathode collector are provided with
cathode active-material coating layers so as not to provide a cathode uncoated
part at a winding beginning portion of the cathode, and the cathode uncoated part
for installation of a cathode lead is provided only at a winding ending portion of
the cathode, and
wherein an insulator tape is attached to the boundary of the cathode active-
material coating layer facing the anode at the winding ending portion of the
cathode.
[2] A battery comprising: a cathode having a cathode active-material coating layer
provided on at least one surface of a cathode collector; and an anode having an
anode active-material coating layer provided on at least one surface of an anode
collector, the cathode and anode being wound to face each other with a separator
interposed therebetween,
wherein both upper and lower surfaces of the cathode collector are provided with
cathode active-material coating layers so as not to provide a cathode uncoated
part at a winding beginning portion of the cathode, and the cathode uncoated part
for installation of a cathode lead is provided only at a winding ending portion of
the cathode,
wherein an additional cathode active-material coating layer is provided on at
least one surface of a distal end of the cathode uncoated-part, and
wherein an insulator tape is attached to the boundary of the cathode active-
material coating layer facing the anode at the winding ending portion of the
cathode.
[3] A battery comprising: a cathode having a cathode active-material coating layer
provided on at least one surface of a cathode collector; and an anode having an
anode active-material coating layer provided on at least one surface of an anode
collector, the cathode and anode being wound to face each other with a separator
interposed therebetween,
wherein cathode uncoated parts are provided at a winding beginning portion and
winding ending portion of the cathode, respectively, such that a cathode lead is
installed on at least one of the cathode uncoated parts provided at the winding

beginning portion and winding ending portion, and an insulator tape is attached
to a distal end of the cathode uncoated part where the cathode lead is installed,
and
wherein an insulator tape is attached to the boundary of the cathode active-
material coating layer facing the anode at the winding ending portion of the
cathode.
[4] The battery according to claim 1 or 2, wherein the cathode active-material
coating layers on both the upper and lower surfaces of the cathode collector have
the same beginning point at the winding beginning portion of the cathode, and
have different lengths from each other at the winding ending portion of the
cathode, whereby at least one surface of the cathode collector includes a non-
coating part not containing the cathode active-material coating layer.
[5] The battery according to claim 1 or 2, wherein, on the basis of the winding
beginning portion, the insulator tape is attached to the boundaries of the cathode
active-material coating layers at distal ends of both the upper and lower surfaces
of the cathode collector.
[6] The battery according to claim 2, wherein, on the basis of the winding beginning
portion, the insulator tape is attached to the boundaries of the cathode active-
material coating layers at distal ends of both the upper and lower surfaces of the
cathode collector and to the boundary of the cathode active-material coating
layer at the distal end of the cathode uncoated part.
[7] The battery according to claim 3, wherein, on the basis of the winding beginning
portion, the insulator tape is attached to the boundaries of the cathode active-
material coating layers at distal ends of both the upper and lower surfaces of the
cathode collector and to the distal end of the cathode collector where the cathode
lead is installed.
[8] The battery according to any one of claims 1 to 3, wherein the insulator tape is
provided during a winding process or electrode coating process.
[9] The battery according to any one of claims 1 to 3, wherein the cathode lead and
an anode lead of the battery are arranged in opposite directions.
[10] The battery according to any one of claims 1 to 3, wherein the anode is provided,
on at least one of a winding beginning portion and winding ending portion
thereof, with an anode uncoated part not containing the anode active-material
coating layer for connection of an anode lead, and wherein the anode collector is
provided, on one surface thereof opposite to the anode lead connected to the
other surface thereof, with two or more insulating layers at a position corre-
sponding to the anode lead.
[11] The battery according to any one of claims 1 to 3, wherein a cut face of an anode

uncoated part provided at a tip end of the anode as a winding beginning portion
is insulated and protected by a plurality of separators.
[12] The battery according to any one of claims 1 to 3, wherein the separator extends
beyond an ending portion of the anode.
[13] The battery according to claim 12, wherein the separator further extends from the
ending portion of the anode by about 5 mm or more.
[14] The battery according to any one of claims 1 to 3, wherein the insulator tape is
one or more selected from the group consisting of a polyimide tape, acetate tape,
glass cloth tape, polyester tape, polyphenylenesulfide (PPS) tape, and
polypropylene tape.
[15] The battery according to claim 14, wherein the insulator tape is a polyethylene
terephthalate tape.
[16] The batteiy according to any one of claims 1 to 3, wherein the insulator tape has
a thickness of about 10µm to 100µm.
[17] A prismatic battery wherein the battery according to claim 1 is received in a
prismatic battery can, and a non-aqueous electrolyte is further provided.
[18] A prismatic battery wherein the battery according to claim 2 is received in a
prismatic battery can, and a non-aqueous electrolyte is further provided.
[19] A prismatic battery wherein the battery according to claim 3 is received in a
prismatic batteiy can, and a non-aqueous electrolyte is further provided.

Disclosed is a battery including a cathode and an anode wound to face each other with a separator interposed there-
between. Both surfaces of a cathode collector are provided with cathode active-material coating layers so as not to provide a cathode
uncoated part at a winding beginning portion of the cathode. The cathode uncoated part for installation of a cathode lead is
provided only at a winding ending portion of the cathode. An insulator tape is attached to the boundary of the cathode active-material
coating layer facing the anode at the winding ending portion of the cathode. Providing the insulator tape to the boundary of
the cathode active-material coating layer at a position where a non-coating part not containing the cathode active-material coating
layer and an anode active-material coating layer face each other achieves enhanced electrical insulation capability and consequential
safety of the battery.