KR100824899B1 - Secondary battery - Google Patents

Abstract

The secondary battery of the present invention is an electrode assembly; A can containing the electrode assembly; A cap assembly that engages with an open top of the can; And an phase insulation member positioned between the electrode assembly and the cap assembly, wherein an outer circumference of the phase insulation member is thinner than an inner portion, and a bead portion pressed inwardly is formed on an outer wall of the can, It is characterized in that the contact with the outer periphery of the upper surface of the upper insulating member.

Therefore, the total height of the electrode assembly can be increased, so that the capacity of the battery can be increased, and the inner part can maintain the conventional thickness and the outer periphery is thinner than the conventional one, thereby preventing damage to the phase insulating member and the electrode assembly. have.

Description

Secondary Battery {SECONDARY BATTERY}

1 is an exploded perspective view illustrating a cylindrical secondary battery according to an embodiment of the present invention;

FIG. 2 is a front sectional view of the secondary battery shown in FIG. 1;

3 is a perspective view of a phase insulating member of a secondary battery according to an embodiment of the present invention;

4 is a partial schematic view of a secondary battery using the phase insulating member of FIG. 3.

Explanation of symbols on the main parts of the drawings

10: can 15: beading part

20: electrode assembly 27: electrode tab

40: phase insulation member 42: outer circumference

44: inner part 46: central hole

100: cap assembly

The present invention relates to a secondary battery, and more particularly, by forming a thin portion of the phase insulating member positioned between the jelly roll and the cap assembly in contact with the beading portion formed by being pressed inward from the outer wall of the can. The present invention relates to a secondary battery which increases the capacitance by increasing the height and decreases the pressure applied to the upper edge portion of the jelly roll to prevent deformation of the jelly roll or deformation of the phase insulating member.

In general, a secondary battery refers to a battery that can be charged and discharged, unlike a primary battery that cannot be charged, and is widely used in the field of advanced electronic devices such as a cellular phone, a notebook computer, a camcorder, and the like. In particular, lithium secondary batteries have an operating voltage of 3.6V, which is three times higher than nickel-cadmium batteries or nickel-hydrogen batteries, which are widely used as electronic equipment power sources, and are rapidly increasing in terms of high energy density per unit weight.

Such lithium secondary batteries mainly use lithium-based oxides as positive electrode active materials and carbon materials as negative electrode active materials. Moreover, although lithium secondary batteries are manufactured in various shapes, typical shapes include cylindrical shape, square shape, and pouch type.

Among these, the cylindrical secondary battery includes an electrode assembly, a cylindrical can housing the electrode assembly, and a cap assembly coupled to an upper portion of the can.

In the electrode assembly, a cathode, a cathode, and a separator interposed between the two electrodes are wound in a cylindrical shape to form a jelly roll, and anode and cathode tabs are drawn out from the anode and the cathode, respectively. Normally, the positive electrode tab is upward and the negative electrode tab is pulled out downward.

The can is a metal container having a substantially cylindrical shape in a cylindrical secondary battery, and is formed by a processing method such as deep drawing. It is therefore possible for the can itself to act as a terminal.

The cap assembly is coupled to the open top of the can, with a gasket insulated between the cap assembly and the can.

The positive electrode of the electrode assembly is electrically connected to one part of the cap assembly through an upwardly drawn positive electrode tab, and the negative electrode is joined to the bottom surface of the can through a negatively negative tab drawn downward. Of course, the polarity can also be changed.

In addition, between the electrode assembly and the cap assembly is a phase insulation member for the insulation of the two, there is a problem in the structure of the conventional phase insulation member as follows.

The conventional phase insulation member is a simple disc shape having a certain thickness. The thinner the phase insulating member, the longer the length of the electrode assembly may increase, and thus the capacity of the battery may be increased. When the phase insulating member becomes thinner than a predetermined level, the electrode assembly and the phase insulating member may be inserted into the can and then outside the can. The upper insulation member may be bent or damaged in some cases when beading inwardly at the inside of the can, or after clamping after the cap assembly is joined to the open top of the can, or when pressing to adjust the total height of the battery after the clamping. As a result, there is a risk of damage to the electrode assembly.

The present invention is to solve the above problems, by forming a thin portion of the phase insulating member positioned between the jelly roll and the cap assembly in contact with the beading portion formed by being pressed inward from the outer wall of the can, the total height of the jelly roll The present invention relates to a secondary battery in which the capacitance is increased to increase the pressure, and the pressure applied to the upper edge portion of the jelly roll is reduced to prevent deformation of the jelly roll or deformation of the phase insulating member.

Secondary battery according to the present invention for achieving the above object,

Electrode assembly; A can containing the electrode assembly; A cap assembly that engages with an open top of the can; And an phase insulation member positioned between the electrode assembly and the cap assembly, wherein an outer circumference of the phase insulation member is thinner than an inner portion, and a bead portion pressed inwardly is formed on an outer wall of the can, It is characterized in that the contact with the outer periphery of the upper surface of the upper insulating member.

In this case, a step may be formed between the outer circumference and the inner portion of the upper surface of the upper insulating member.

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

1 and 2, the cylindrical secondary battery includes an electrode assembly 20, a can 10 containing the electrode assembly 20, and a cap assembly 100 coupled to the can 10. .

The electrode assembly 20 typically forms two different electrodes 25 in a wide plate shape in order to increase capacitance, and thereafter, separators 21 and 23 are insulated from each other and positioned below or above the two electrodes. It is then laminated, rolled up in a circle to form a so-called 'Jelly Roll'. The two electrode plates are formed by coating an active material slurry on a current collector made of metal foil or metal mesh made of aluminum and copper, respectively. In the direction in which the electrode plate is wound, there is a non-coated portion at which the slurry is not applied at the start and end of the current collector. In the uncoated portion, electrode tabs 27 and 29 are provided one by one in the electrode plate, and the electrode tabs may be formed to be drawn out from the electrodes, one upward in the direction of the opening of the cylindrical can and the other downward. Both may be formed to be drawn upward in the opening direction.

The can 10 has a cylindrical shape as shown, is a container made of a lightweight conductive metal such as aluminum or an aluminum alloy, and is formed by a processing method such as deep drawing. The lower insulating member 30, the electrode assembly 20, and the upper insulating member 40 are sequentially installed in the cylindrical can 10. At this time, the center pin (not shown) that prevents the release of the jelly roll and serves as a movement passage of the internal gas may be inserted into the empty space in the center of the jelly roll.

The electrode tab 29 drawn downward is bent to be parallel to the bottom surface of the jelly roll type electrode assembly 20 and welded to the bottom surface of the cylindrical can 10. At this time, the lower insulating member 30 is positioned between the bent electrode tab 29 and the lower surface of the electrode assembly 20 such that the lower surface of the electrode assembly 20 is not short-circuited with the bottom surface of the can 10.

On the other hand, the upper insulating member 40 serves to insulate between the upper surface of the electrode assembly 20 and the cap assembly 100, a detailed description thereof will be described later.

In the cylindrical can 10 in which the lower insulating member 30, the electrode assembly 20, and the upper insulating member 40 are accommodated, the outside of the can 10 of the upper portion of the upper insulating member 40 is formed on the outside. By pressing inwards to form the beading portion 15, the flow of the electrode assembly 20 is prevented.

Thereafter, the electrolyte is injected into the cylindrical can. This electrolyte serves to move lithium ions generated by the electrochemical reaction in the electrode 25 during charging and discharging.

As shown in the cap assembly 100, the vent 110, the current breaker 120, the PTC 130, and the cap up 140 are located in order from the bottom. Vent 110 is located at the bottom of the cap assembly 100, the central portion of the event 110 has a protrusion 112 is convexly protruded downward and electrically connected to the electrode tab 27. A current interrupter (CID) 120 is formed above the vent 110 so that the protrusion 112 of the vent 110 is broken by being convexly deformed by the internal pressure. A PTC (Positive Thermal Coefficient) 130 is provided above the current breaker 120, which blocks the flow of current in the battery by overheating of the battery. A cap up 140 having an electrode terminal formed convexly formed to be electrically connected to the outside is provided above the PTC.

A gasket 150 is positioned between the upper portion of the can 10 and the cap assembly 100 to seal and insulate the can 10 from the cap assembly 100.

The structure of the phase insulation member 40 is as follows.

3 and 4, the outer circumferential edge 42 of the upper insulation member 40 is thinner than the inner portion 44, and the outer circumferential edge 42 of the upper surface of the upper insulation member 40 is formed of the can 10. In contact with the beading portion 15 formed by being pressed inward from the outer wall.

Here, the difference in the thickness of the outer circumferential edge 42 and the inner portion 44 may be due to the stepped between the outer circumferential edge 42 and the inner portion 44 as shown. Accordingly, the thickness of the inner portion 44 can maintain the conventional thickness, so that the upper insulation member is bent or damaged when beading the can outer wall inward, when clamping, or when pressing to conform to a predetermined standard. It is possible to prevent the risk of damage, and thus to prevent damage to the electrode assembly. In addition, by forming the thickness of the outer periphery 42 thinner than the conventional, the total height of the electrode assembly can be increased, and eventually the capacity of the battery can be increased. In addition, since the thickness of the outer circumferential edge 42 is made thinner than before, the effect that the outer circumferential edge 42 of the upper insulation member 40 is pressed by the beading portion 15 is remarkably reduced than before, and thus the phase insulation member ( 40) and to prevent damage to the electrode assembly.

At this time, the width of the outer periphery 42 of the upper insulating member 40 is preferably formed to be larger than the depth to the inside of the beading portion 15. If the width of the outer circumferential edge 42 is smaller than the depth to the inside of the beading portion 15 so that the beading portion 15 contacts the upper surface of the inner portion 44, the outer circumferential edge 42 and the inner portion 44 in the present invention. This is because the meaning of forming a step is lost.

In addition, the lower surface of the upper insulating member 40 is preferably flat. It is sufficient to give a step on the upper surface of the upper insulating member 40 to give a difference in thickness between the outer periphery and the inner part of the upper insulating member 40, and if the lower surface of the upper insulating member 40 is bent or gives a step, this is rather This reduces the total cell weight, which reduces the capacity of the battery.

On the other hand, the central hole 46 for the outflow of the internal gas may be formed in the center of the inner portion 44 of the upper insulating member 40. This is to form a central hole 46 so that the phase insulation member 40 does not block when the gas generated inside the battery moves upward through the empty space of the jelly roll.

According to the invention,

First, the thickness of the inner portion can maintain the conventional thickness, and can prevent the risk of bending or damaging the phase insulation member when beading the outer wall of the can inward, clamping, or pressing to meet a certain standard. Therefore, damage to the electrode assembly can be prevented.

Second, by forming a thickness of the outer periphery thinner than the conventional, the total height of the electrode assembly can be increased, and eventually the capacity of the battery can be increased. In addition, since the thickness of the outer peripheral edge is made thinner than the conventional, the effect that the outer peripheral edge of the phase insulating member is pressed by the bead portion is significantly reduced compared with the conventional, there is also a side to prevent damage to the phase insulating member and the electrode assembly.

Although the present invention has been described with reference to the illustrated embodiments, it is merely exemplary, and the present invention may encompass various modifications and equivalent other embodiments that can be made by those skilled in the art. Will understand.

Claims (6)

Electrode assembly; A can containing the electrode assembly; A cap assembly that engages with an open top of the can; And Phase insulating member positioned between the electrode assembly and the cap assembly Including, The outer periphery of the upper insulating member is thinner than the inner portion, the beading portion is pressed inward on the outer wall of the can, the beading portion is in contact with the outer periphery of the upper surface of the upper insulating member, the outer The width of the peripheral edge is formed larger than the depth to the inside of the bead portion. The method of claim 1, Secondary battery has a step formed between the outer periphery and the inner portion of the upper surface of the upper insulating member. delete The method of claim 1, A secondary battery having a lower surface of the phase insulating member is formed flat. The method of claim 1, Secondary battery formed with a central hole for the outflow of the internal gas in the center of the inner portion of the phase insulating member. The method according to any one of claims 1, 2, 4 or 5, The can is a cylindrical secondary battery.

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