KR100686850B1 - Cylindrical type lithium secondary battery - Google Patents

Abstract

Provided is a cylindrical lithium secondary battery having a swellable lower insulating plate, wherein an electrode assembly is fixed to the inside of a can when external shock such as vibration and collision is applied to a battery. The cylindrical lithium secondary battery comprises: an electrode assembly(110) of jelly roll type that has a negative electrode plate with a negative electrode tap(114), a positive electrode plate with a positive electrode tap(115), and a separator interposed between the negative electrode plate and positive electrode plate; a cylindrical can(130) having the electrode assembly(110) within; a cap assembly combined with the upper part of the can(130); and a lower insulating plate(116). The lower insulating plate(116) is placed between the lower part of the electrode assembly(110) and the bottom of the can(130) and is swellable to fix the electrode assembly(110).

Description

Cylindrical lithium secondary battery {Cylindrical type Lithium Secondary Battery}

1A, 1B and 1C are perspective, cross-sectional and exploded perspective views illustrating a cylindrical lithium secondary battery according to one embodiment of the present invention, FIG. 1D is an enlarged plan view of a lower insulating plate, and FIG. 1E is centered on a lower insulating plate. An enlarged cross sectional view showing a state where a pin is inserted.

2 is an enlarged plan view of a lower insulating plate of a cylindrical lithium secondary battery according to another embodiment of the present invention.

3 is an enlarged plan view of a lower insulating plate of a cylindrical lithium secondary battery according to another embodiment of the present invention.

4 is an enlarged plan view of a lower insulating plate of a cylindrical lithium secondary battery according to another embodiment of the present invention.

<Brief Description of Major Codes in Drawings>

100: cylindrical lithium secondary battery 111: negative electrode plate

112: positive electrode plate 113: separator

114: negative electrode tab 115: positive electrode tab

116: lower insulation plate 116a: stepped portion

117: upper insulation plate 120: center pin

125,225,325,425: Hall 127,227,327,427: Home

130: can 131: cylindrical surface

132: bottom surface 133: bead

134: crimping portion 140: cap assembly

141: gasket 142: safety vent

143: circuit board 143a: wiring pattern

144: positive temperature element 145: anode cap

145a: through

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithium secondary battery, and more particularly, by having a lower insulating plate that can be swelled, whereby an electrode assembly can be fixed inside a can in various situations such as vibration, shock, dropping, crushing, and collision. It relates to a cylindrical lithium secondary battery that can be.

In general, a cylindrical lithium secondary battery includes an electrode assembly in the form of a jelly roll, a cylindrical can in which the electrode assembly is coupled, an electrolyte that is injected into the can to allow lithium ions to move, and is coupled to one side of the can to And a cap assembly for preventing leakage and preventing separation of the electrode assembly. In addition, a center pin may be further installed at the center of the electrode assembly such that the jelly roll-shaped electrode assembly is not deformed.

Since the cylindrical lithium secondary battery generally has a capacity of about 2000 to 2400 mA, the cylindrical lithium secondary battery is mainly mounted on a note PC, a digital camera, a camcorder, or the like, which requires a large amount of power. For example, a plurality of cylindrical lithium secondary batteries are connected in series and in parallel as many as necessary, and are assembled into a hard pack of a predetermined type with a protection circuit installed therein and used to be coupled to a power source for an electronic device.

In addition, in the method of manufacturing the cylindrical lithium secondary battery, a negative electrode plate coated with a negative electrode active material, a separator, and a positive electrode plate coated with a positive electrode active material are laminated together, and one end is bonded to a rod-shaped winding shaft, and then wound in a substantially cylindrical shape to form an electrode. To form an assembly. The electrode assembly is then inserted into the cylindrical can and then the center pin is inserted into the electrode assembly. Subsequently, an electrolyte solution is injected into the cylindrical can, and the cap assembly is coupled to the upper portion of the cylindrical can, thereby completing a substantially cylindrical lithium secondary battery.

However, in the cylindrical lithium secondary battery as described above, the electrode assembly in the form of a jelly roll rotates in a predetermined direction or extends in a longitudinal direction (up and down directions) in a state of vibration, shock, drop, crushing, and collision. Therefore, the phenomenon of moving in a predetermined direction may occur. In addition, the flow of the electrode assembly increases the contact resistance of various metal connection (or connection) sites, thereby reducing the maximum output that the battery can output. In addition, in a state of vibration, impact, drop, crush, and collision, the center pin inserted into the center of the electrode assembly may also move to cause deformation of the electrode assembly. As a result, a short circuit between the electrodes may occur to cause ignition and explosion of the battery. Therefore, there is a problem that the safety and reliability of the battery is poor.

On the other hand, in order to prevent the explosion phenomenon during overcharging, such a cylindrical lithium secondary battery is provided with a safety vent that is deformed when the internal pressure increases due to overcharging, and a circuit board which blocks current by changing the shape of the safety vent. Safety vents and circuit boards are commonly referred to collectively as current interrupt devices (CIDs), which are one component of the cap assembly.

The operation of the safety vent and the circuit board of the cylindrical lithium secondary battery will be described in more detail as follows.

For example, when the cylindrical lithium secondary battery is in an overcharged state, the electrolyte begins to increase in resistance from the approximately upper region of the electrode assembly. Moreover, at this time, lithium begins to deform from approximately the center region of the electrode assembly. Of course, as the resistance of the upper region of the electrode assembly increases, heat generation starts locally, and the battery temperature also rapidly increases.

In such a state, the internal pressure is rapidly increased by the action of cyclohexyl benzene (CHB) and biphenyl (BP) (electrolyte additive), which decomposes during overcharging and generates gas. This internal pressure pushes the safety vent, one component of the cap assembly outward (ie, outward), thereby breaking the current by breaking the circuit board installed thereon. In other words, the wiring pattern formed on the circuit board is broken so that no current flows any more. Of course, when the current is cut off, the overcharge state is prevented, thereby preventing heat generation, leakage, smoke, explosion, and ignition of the battery.

On the other hand, when the internal pressure of the battery is higher than the threshold due to the overcharge phenomenon as described above, the safety vent itself may be torn and all the internal gas may be released to the outside.

However, in general, cyclohexyl benzene, biphenyl, and the like, which are additives of the electrolyte, have a limitation in that they cannot be sufficiently added to the electrolyte because the capacity of the battery is reduced. That is, there is a trade off relationship between cyclohexyl benzene and biphenyl added to the electrolyte, and the capacity, water surface, and quality of the battery.

As a result, although there is a slight difference depending on the type of battery, if the pressure for deforming the safety vent inside the battery (or the pressure for destroying the circuit board) is about 5 to 11 Kgf / cm ² , the pressure for the safety vent is deformed. It is known that 10-22 ml of gas is required. However, even if all the hexyl benzene in the 0.7% cycle contained in the electrolyte is decomposed, approximately 4.116 ml of gas is generated, and even if all 0.3% of biphenyls are decomposed, approximately 1.833 ml of gas is generated. In addition, approximately 1.5 ml of gas is generated in the chemical conversion process. However, when all three of these gases are combined, it is only about 7.449 ml, which is about 3.75 It will only apply a force of Kgf / cm ² to the safety vent. In other words, the pressure to deform the safety vent during overcharging or thereby destroy the circuit board requires approximately 5 to 11 Kgf / cm ² , but there is a limit to the amount of additives that can actually be added to the electrolyte, and also the void volume. Due to gas roughly 3.75 By providing only Kgf / cm ² , the safety vent does not operate or the operating time of the safety vent is delayed. In other words, the current blocking time is delayed during overcharging. Therefore, there is a problem in that overcharge proceeds further by the delayed time and the battery temperature further increases, so that the probability of explosion or ignition of the battery becomes very high.

Moreover, the conventional battery is maintained at a high temperature state by overcharging. As is well known, since the electrolyte mainly consists of an organic solvent which is easy to burn, it is easily smoked and ignited by an electrical spark or the like at such a high temperature state. There is.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a lower insulating plate that can be swelled, thereby providing an electrode in various situations such as vibration, shock, dropping, crushing and collision. It is to provide a cylindrical lithium secondary battery in which the assembly can be fixed inside the can and the center pin inserted into the center portion of the electrode assembly can be fixed.

Another object of the present invention is to form a lower insulating plate with a swelling resin, so that the nickel tab can be fixed to the can and the void volume (or dead space) present in the can is reduced to reduce the content of the electrolyte additive. It is to provide a cylindrical lithium secondary battery that can be reduced.

Cylindrical lithium secondary battery according to the present invention for achieving the above object is an electrode assembly having a negative electrode tab is attached, the positive electrode tab is attached to the positive electrode plate and the separator is disposed between the negative electrode plate and the positive electrode plate wound in a jelly roll form; A circular can containing the electrode assembly; And a cap assembly coupled to an upper portion of the can, and between the lower portion of the electrode assembly and the bottom surface of the can, a lower insulating plate capable of swelling to fix the electrode assembly is provided. do.

The cylindrical lithium secondary battery according to the present invention may further include a center pin inserted into a hole formed in the center of the lower insulating plate passing through the central portion of the electrode assembly.

The center pin may be inserted into and fixed to the hole of the lower insulating plate.

The center portion of the lower insulating plate may include a stepped portion formed to be stepped with another region by extending a predetermined distance toward the cap assembly in a direction surrounding the periphery of the hole.

The lower insulating plate may be made of a swelling resin, and the lower insulating plate may be selected from any one of poly butylene terephthalate and poly vinylidene fluoride.

The inner outer circumferential portion and the outer outer circumferential portion of the stepped portion may be formed in a circular plane.

The inner circumferential portion of the stepped portion may have a hexagonal plane, and the outer circumferential portion may have a circular plane shape.

The inner circumferential portion of the stepped portion may be circular in planar shape, and the outer circumferential portion of the stepped portion may be hexagonal in plane.

The inner outer circumferential portion and the outer outer circumferential portion of the stepped portion may be formed in a hexagonal plane.

A groove through which the negative electrode tab passes may be formed at one side of the peripheral portion of the lower insulating plate.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1A, 1B and 1C are perspective, cross-sectional and exploded perspective views illustrating a cylindrical lithium secondary battery according to one embodiment of the present invention, FIG. 1D is an enlarged plan view of a lower insulating plate, and FIG. 1E is centered on a lower insulating plate. An enlarged cross sectional view showing a state where a pin is inserted.

First, as shown in FIGS. 1A, 1B, and 1C, the cylindrical lithium secondary battery 100 according to the exemplary embodiment of the present invention includes an electrode assembly 110 and a center pin 120 coupled to the electrode assembly 110. ), A can 130 containing the electrode assembly 110 and the center pin 120, and a cap assembly 140 blocking an upper portion of the can 130. In addition, the cylindrical lithium secondary battery 100 according to the present invention, between the lower portion of the electrode assembly 110 and the bottom surface 132 of the can 130, the swell to fix the electrode assembly 110 and the center pin 112. It further includes a lower insulating plate 116 capable of swelling.

The electrode assembly 110 includes a negative electrode plate 111 coated with a negative electrode active material (eg, graphite, carbon, etc.), a positive electrode active material (eg, a transition metal oxide (LiCoO ₂ , LiNiO _{2 ,} LiMn ₂ O _4, etc.)). It is composed of a coated anode plate 112 and a separator 113 positioned between the cathode plate 111 and the anode plate 112 to prevent shorting and allow only movement of lithium ions. The cathode plate 111 and the cathode plate ( 112 and the separator 113 are wound in a substantially cylindrical shape and stored in the cylindrical can 130. Here, the negative electrode plate 111 may be a copper (Cu) foil, the positive electrode plate 112 may be an aluminum (Al) foil, and the separator 113 may be polyethylene (PE) or polypropylene (PP). It is not intended to limit. In addition, the negative electrode tab 114 protruding a predetermined length downwardly may be welded to the negative electrode plate 111, and the positive electrode tab 115 protruding a predetermined length upwardly may be welded to the positive electrode plate 112, and vice versa. In addition, the negative electrode tab 114 may be made of nickel (Ni) and the positive electrode tab 115 may be made of aluminum (Al), but the present invention is not limited thereto.

The center pin 120 is coupled to approximately the center of the electrode assembly 110, which serves to suppress deformation of the electrode assembly 110 during charging and discharging of the battery. The center pin may be formed of a metal material, and a chamber or a taper having a smaller diameter may be formed at each of the upper and lower ends so as to be easily inserted into the center of the electrode assembly. Of course, it does not limit this invention to this form.

The can 130 has a substantially cylindrical shape, a cylindrical surface 131 having a predetermined diameter is formed, a bottom surface 132 having a substantially disk shape is formed at a lower portion of the cylindrical surface 131, and an upper portion thereof is open. . Thus, the electrode assembly 110 and the center pin 120 can be inserted directly through the top of the cylindrical can 130 to the bottom. Here, the negative electrode tab 114 of the electrode assembly 110 may be welded to the bottom surface 132 of the cylindrical can 130. Thus, the cylindrical can 130 can operate as a cathode. On the contrary, the positive electrode tab 115 may be welded to the bottom surface 132 of the cylindrical can 130, in which case the cylindrical can 130 may operate as the positive electrode. In addition, the lower insulating plate 116 and the upper insulating plate 117 are positioned on the lower surface of the electrode assembly 110, respectively, to prevent unnecessary electrical shorts between the electrode assembly 110 and the cylindrical can 130. Meanwhile, the cylindrical can 130 may be formed of steel, stainless steel, aluminum, or an equivalent thereof, but the material is not limited thereto.

The cap assembly 140 has an insulating gasket 141 coupled to the upper region of the cylindrical can 130 (that is, the upper region of the electrode assembly 110 and the center pin 120) in a substantially ring shape, and the insulating gasket 141. The conductive safety vent 142 may be combined. Here, the positive electrode tab 115 may be connected to the safety vent 142. Of course, the negative electrode tab 114 may be connected to the safety vent 142. As is well known, the safety vent 142 may be deformed or ruptured when the pressure rises inside the can 130 to damage the circuit board 143 to be described below or to release gas to the outside. In addition, the upper portion of the safety vent 142 is further located a circuit board 143 that breaks or is destroyed when the safety vent 142 is deformed to cut off the current, the upper portion of the circuit board 143 is blocked the current in the overcurrent Positive temperature element 144 is located. In addition, an anode cap 145 (or cathode cap) having a plurality of through holes 145a formed therein to provide an anode voltage (or cathode voltage) to the outside on the positive temperature element 144 to facilitate gas discharge. It is. Of course, the safety vent 142, the circuit board 143, the positive temperature element 144, and the positive electrode cap 145 described above are all mounted inside the insulating gasket 141, thereby directly contacting the cylindrical can 130. Short is prevented. In addition, a wiring pattern 143a is formed on the surface of the circuit board 143. The wiring pattern 143a is naturally broken when the circuit board 143 is broken or broken.

On the other hand, the cylindrical can 130 has a beading part 133 recessed therein is formed in the lower part of the cylindrical assembly 130 so as to prevent the cap assembly 140 from being separated outwardly. A crimping part 134 bent into the inside is formed. The beading part 133 and the crimping part 134 serve to securely fix and support the cap assembly 140 to the cylindrical can 130, and also to prevent the electrolyte to be leaked to the outside.

In addition, an electrolyte solution (not shown) is injected into the cylindrical can 130, and lithium ions generated by electrochemical reactions in the negative electrode plate 111 and the positive electrode plate 112 inside the battery during charge and discharge are injected. It serves to make it mobile. The electrolyte may be a non-aqueous organic electrolyte that is a mixture of lithium salts and high purity organic solvents. In addition, the electrolyte may be a polymer using a polymer electrolyte, and the type of the electrolyte is not limited thereto.

Subsequently, as shown in FIGS. 1D and 1E, the lower insulating plate 116 of the cylindrical lithium secondary battery according to the exemplary embodiment of the present invention surrounds the periphery of the hole 125 in which the center pin 120 is inserted in the center thereof. The step is extended by a predetermined distance in the direction of the cap assembly, the stepped portion 116a formed to be stepped with the other area, and the groove 127 through which the negative electrode tab 114 is welded to the bottom surface 132 of the can 130 on one side of the peripheral portion. ).

The lower insulating plate 116 is formed between the bottom of the electrode assembly 110 and the bottom surface 132 of the can 130 to insulate the electrode assembly 110 and the bottom surface of the can 130. The lower insulating plate 116, which is a feature of the present invention, is a resin capable of swelling to fix the electrode assembly 110 and the center pin 120, for example, poly butylene terephthalate or poly. Polyvinylidene fluoride and the like. The lower insulating plate 160 made of a resin capable of swelling is expanded in the can 130 in which the electrolyte is stored, thereby fixing the electrode assembly 130 and the center pin 120. Particularly, when the stepped portion 116a of the lower insulating plate 160 is swelled, the inside of the stepped portion 116a is swelled in the direction of the center pin 120 inserted into the center of the electrode assembly 130 to be center pin 120. ) And the outside of the stepped portion 116a is swelled in the direction of the cylindrical surface 131 of the can 130 to fix the electrode assembly. Of course, in addition to the step portion 116a, other regions of the lower insulating plate 160 are swelled up, down, left, and right to fix the electrode assembly 130 between the bottom surface 132 of the can 130 and the beading portion 133. In addition, the electrode assembly 130 is fixed between the center pin 120 and the cylindrical surface 131 of the can 130.

As such, the lower insulating plate 160 may expand in the electrolyte to reduce the void volume or dead volume existing in the can 130. As such, when the void volume or the dead volume is reduced, the gas required for deformation of the safety vent during overcharging of the battery is reduced. Accordingly, the lower insulating plate 160 of the cylindrical lithium secondary battery according to the present invention is a cyclohexyl benzene (CHB) and bis by generating gas to rapidly increase the internal pressure during overcharging in the conventional cylindrical lithium secondary battery. Electrolyte additives, such as phenyl (BP), can be reduced. Accordingly, the cylindrical lithium secondary battery having the swelled lower insulating plate 116 of the present invention can reduce electrolyte additives such as cyclohexyl benzene (CHB) and biphenyl (BP), thereby reducing electrolyte. Lithium ion movement through is facilitated. Therefore, the capacity of the battery can be increased.

In addition, the negative electrode tab 114 passes through the groove 127 formed in the lower insulating plate 116 to the bottom surface 132 of the can 130 by pressing the negative electrode tab 114. It serves to be folded and fixed to the bottom surface 132).

Here, the stepped portion 116a of the lower insulating plate 116 may be formed by forming an inner outer circumferential portion and an outer outer circumferential portion in a planar circular shape. The stepped portion 116a may be formed in various forms, examples of which will be shown in FIGS. 2 to 4.

2 is an enlarged plan view of a lower insulating plate of a cylindrical lithium secondary battery according to another embodiment of the present invention, and FIG. 3 is an enlarged plan view of a lower insulating plate of a cylindrical lithium secondary battery according to another embodiment of the present invention. 4 is an enlarged plan view of a lower insulating plate of a cylindrical lithium secondary battery according to still another embodiment of the present invention.

The lower insulating plates shown in FIGS. 2 to 4 have the same materials and functions as the lower insulating plates of the cylindrical lithium secondary battery according to the exemplary embodiment of the present invention, and thus the description of the same components will be omitted. .

As shown in FIG. 2, in the lower insulating plate 216 of the cylindrical lithium secondary battery according to another exemplary embodiment of the present invention, an area surrounding the periphery of the hole 225 in which the center pin is inserted is defined in the direction of the cap assembly. It includes a step 216a and a groove 227 passing so that the negative electrode tab is welded to the bottom surface of the can, the stepped portion 216a formed to be stepped apart from other regions. Here, the stepped portion 216a of the lower insulating plate 216 may be formed by forming an inner outer circumferential portion in a planar hexagon and an outer outer circumferential portion in a planar circular shape.

As shown in FIG. 3, the lower insulating plate 316 according to another embodiment of the present invention extends a predetermined distance in the direction of the cap assembly in a region surrounding the periphery of the hole 325 into which the center pin is inserted. The stepped portion 316a and the negative electrode tab formed to be stepped with the region include a groove 327 passing through to be welded to the bottom of the can. Here, the stepped portion 316a of the lower insulating plate 316 may be formed by forming an inner outer circumferential portion in a planar circular shape and an outer outer circumferential portion in a planar hexagon.

As shown in FIG. 4, the lower insulation plate 416 according to another embodiment of the present invention extends a predetermined distance in the direction of the cap assembly in a region surrounding the periphery of the hole 425 into which the center pin is inserted. A step 441a formed to step with the region and a groove 427 passing through the negative electrode tab to be welded to the bottom surface of the can. Here, the stepped portion 416a of the lower insulating plate 416 may be formed by forming an inner outer peripheral portion and an outer outer peripheral portion in a planar hexagon.

2 to 4 are formed between the bottom of the electrode assembly and the bottom surface of the can in the same manner as the bottom insulation plate of the cylindrical lithium secondary battery according to the exemplary embodiment of the present invention. It serves to insulate the surface and is formed of a swelling resin to fix the center pin inserted in the center of the electrode assembly and the electrode assembly.

As described above, the cylindrical lithium secondary battery according to the present invention forms a lower insulating plate capable of swelling, thereby fixing the electrode assembly in the can in a vibration, shock, drop, crush, and collision situation of the battery to provide various types of metals. The contact resistance to the connection can be reduced to keep the maximum output voltage constant.

In addition, the cylindrical lithium secondary battery according to the present invention by forming a lower insulating plate capable of swelling (swelling) to fix the center pin inserted in the center of the electrode assembly in the vibration, shock, drop, crushing and collision of the battery stationary By preventing deformation of the electrode assembly to prevent short between the electrodes, it is possible to prevent the battery from ignition and explosion.

In addition, the cylindrical lithium secondary battery according to the present invention allows the lower insulating plate to expand in the swelling electrolyte, thereby reducing the void volume or dead volume existing in the can. As such, when the void volume or the dead volume is reduced, the gas required for deformation of the safety vent during overcharging of the battery is reduced. Accordingly, the cylindrical lithium secondary battery according to the present invention having the swelled lower insulating plate may reduce the amount of the electrolyte additive that generates gas to rapidly increase the internal pressure during overcharging in the conventional cylindrical lithium secondary battery. . Therefore, the capacity of the battery can be increased by making lithium ion migration easier.

In addition, the cylindrical lithium secondary battery according to the present invention can be fixed by pressing the electrode tab passing through the groove formed in the lower insulating plate to the bottom surface of the can.

As described above, the present invention is not limited to the specific preferred embodiments described above, and any person having ordinary skill in the art to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Various modifications are possible, of course, and such changes are within the scope of the claims.

Claims (11)

An electrode assembly having a negative electrode tab attached to the negative electrode tab, a positive electrode plate attached to the positive electrode tab, and a separator positioned between the negative electrode plate and the positive electrode plate laminated and wound in a jelly roll shape; A circular can containing the electrode assembly; And In the cylindrical lithium secondary battery provided with a cap assembly coupled to the top of the can, And a lower insulating plate between the lower portion of the electrode assembly and the bottom surface of the can, the lower insulating plate being swellable to fix the electrode assembly. The method of claim 1, A hole is formed in the center of the lower insulating plate, the cylindrical lithium secondary battery further comprises a center pin inserted into the hole through the center portion of the electrode assembly. The method of claim 2, The center pin is a cylindrical lithium secondary battery, characterized in that fixed to the hole of the lower insulating plate. The method of claim 3, The center portion of the lower insulating plate is a cylindrical lithium secondary battery includes a stepped portion formed to be stepped with other areas extending a predetermined distance toward the cap assembly direction surrounding the periphery of the hole. The method of claim 4, wherein The lower insulating plate is a cylindrical lithium secondary battery, characterized in that made of a swelling (swelling) resin. The method of claim 5, The lower insulating plate is a cylindrical lithium secondary battery, characterized in that made of one selected from poly butylene terephthalate (Poly butylene terephthalate) and poly vinylidene fluoride (Poly vinylidene fluoride). The method of claim 4, wherein A cylindrical lithium secondary battery, characterized in that the inner peripheral portion and the outer peripheral portion of the step portion is formed in a circular plane. The method of claim 4, wherein The inner peripheral portion of the stepped portion is a planar hexagon, the outer peripheral portion is a cylindrical lithium secondary battery, characterized in that consisting of a circular plane. The method of claim 4, wherein A cylindrical lithium secondary battery, wherein the inner peripheral portion of the stepped portion is flat in a circular shape, and the outer peripheral portion is formed in a flat hexagon. The method of claim 4, wherein An inner outer peripheral portion and an outer outer peripheral portion of the stepped portion is a cylindrical lithium secondary battery, characterized in that formed in a hexagonal plane. The method according to claim 1 or 2, Cylindrical lithium secondary battery, characterized in that a groove through which the negative electrode tab is formed on one side of the peripheral portion of the lower insulating plate.

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