KR100938062B1 - Rechargeable battery and the fabricating method thereof - Google Patents

Abstract

The secondary battery of the present invention and a method of manufacturing the same by pressing a part of the crimping portion to enhance the close contact between the top of the can and each part of the gasket and the cap assembly, thereby minimizing the flow caused by external vibration and impact to minimize the internal resistance of the battery Increase of (IR) can be suppressed.

Secondary Battery, Crimping Part, Flow, Internal Resistance, Pressing Part

Description

Secondary Battery and Manufacturing Method Thereof {RECHARGEABLE BATTERY AND THE FABRICATING METHOD THEREOF}

The present invention is to improve the close contact between the top of the can and each part of the gasket and the cap assembly, to minimize the flow caused by external vibration and impact to suppress the increase of the internal resistance (IR) of the battery and its It relates to a manufacturing method.

In general, a rechargeable battery refers to a battery that can be charged and discharged, unlike a primary battery that is not rechargeable, and is widely used in advanced electronic devices such as a cellular phone, a notebook computer, and a camcorder. 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 a lithium secondary battery is 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.

The electrode assembly has a cathode and a cathode, and a separator interposed between the two electrodes is wound in a cylindrical shape to form a jelly roll, and the positive and negative electrode tabs are drawn out from the positive and negative electrodes, 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. Thus, it is also possible for the can itself to serve 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 cap assembly may include several component elements, such as safety vents, current blocking means, PTCs, and cap ups.

In addition, between the electrode assembly and the cap assembly, an upper insulation plate for the insulation of the two is positioned, and a lower insulation plate for the insulation of the two is positioned between the electrode assembly and the bottom surface of the can.

The assembly process of the cylindrical secondary battery includes an electrode assembly forming process, an insertion process for inserting the lower insulating plate and the electrode assembly into the cylindrical can, a welding process for welding the negative electrode tab to the bottom of the can, and an outer wall of the can just above the upper insulating plate. A beading process that presses inwards to form a beading part, an electrolyte injection process for injecting electrolyte into the can, a seating process for inserting a gasket into the bead to rest on the beading part, and welds the positive electrode tab to one part of the cap assembly. Welding process, the seating process of seating the cap assembly on the gasket, the crimping process of sealing the inside of the can using the elasticity of the gasket by bending the upper end of the can, and the upper part of the battery to meet the height of the standard. Pressing is performed in the order of a pressing process.

Such secondary batteries may be placed in various environments as power sources for electrical and electronic equipment. For example, the secondary battery may be used as a power source for a power tool such as a drill. Since the power tool often requires instantaneous power, the smaller the internal resistance IR of the battery, the better.

By the way, since the power tool vibrates or impacts severely, the secondary battery used for the power tool may have an uneven contact between the parts of the cap assembly due to external factors, thereby increasing the internal resistance.

An object of the present invention is to strengthen the close contact between the top of the can and each part of the gasket and the cap assembly, thereby minimizing the flow caused by external vibration and shock to suppress the increase of the internal resistance (IR) of the battery And to provide a method for producing the same.

A secondary battery according to the present invention for achieving this object,

An electrode assembly, a can housing the electrode assembly, a cap assembly closing an open top of the can, and a gasket positioned between the open top of the can and the cap assembly,

The can is characterized in that it comprises a crimping portion (crimping) formed in the form bent inwardly from the top, and a plurality of pressing portion formed in some of the crimping portion.

The plurality of pressing parts may be formed in the shape of a groove that enters downward from the upper surface of the crimping portion.

The crimping portion may have a circular annular vertical cross section.

The plurality of pressing units may be symmetrically formed with respect to the central axis of the electrode assembly, and a distance between two neighboring pressing units among the plurality of pressing units may be constant.

The can may further include a beading portion projecting from the outside inward along the outer circumference of the portion between the electrode assembly and the gasket.

An outer shape of the electrode assembly and the can may be cylindrical.

On the other hand, the secondary battery manufacturing method according to the present invention for achieving the above object,

Manufacturing an electrode assembly and a cap assembly; Receiving the electrode assembly in a can; Positioning a gasket between the open top of the can and the cap assembly, and first pressing the top of the can to form a crimping portion to seal between the can, the gasket, and the cap assembly; And forming a plurality of pressing portions by pressing a second portion of the crimping portion.

The second pressing may be performed by a crimping jig in which protrusions are formed.

The second pressurization may be after the first pressurization.

The second pressing may be made downward from the upper surface of the crimping portion.

Receiving the electrode assembly in the can, may include pressing the inward from the outside along the outer periphery of the portion between the electrode assembly and the gasket in the can to form a beading (beading).

The secondary battery according to the present invention and a method for manufacturing the same, by pressing a part of the crimping portion to strengthen the close contact between the top of the can and each part of the gasket and the cap assembly, thereby minimizing the flow caused by external vibration and impact of the battery An increase in the internal resistance IR can be suppressed.

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

1 is an exploded perspective view of a cylindrical secondary battery according to an embodiment of the present invention, FIG. 2 is a front sectional view of a cylindrical secondary battery according to an embodiment of the present invention, and FIG. 3 is a plan view of the cylindrical secondary battery shown in FIG. 2. to be.

1 and 2, the cylindrical secondary battery 500 may include an electrode assembly 100, a can 200 housing the electrode assembly 100, a cap assembly 300 coupled to the can 200, and a cap assembly 300 coupled to the can 200. And a gasket 400 electrically insulating the can 200 and the cap assembly 300. The cylindrical secondary battery 500 is in close contact with the can 200 and the cap assembly 300 and the gasket 400 to suppress the increase in the internal resistance.

The electrode assembly 100 is formed in a cylindrical shape including a positive electrode plate 110, a negative electrode plate 120, and a separator 130. In addition, the electrode assembly 100 may include a positive electrode tab 115 and a negative electrode tab 125.

The positive electrode plate 110 includes a positive electrode current collector, a positive electrode active material layer, and a positive electrode non-coating portion. The positive electrode current collector is formed of a conductive metal material, for example, aluminum, to collect electrons from the positive electrode active material layer and move them to an external circuit. The cathode active material layer is prepared by mixing a cathode active material, a conductive material and a binder, and is formed by coating a predetermined thickness on the cathode current collector. The positive electrode non-coating portion is a portion in which a positive electrode active material layer is not formed in the positive electrode current collector. The positive electrode tab 115 is welded to one side of the positive electrode non-coating portion.

The negative electrode plate 120 includes a negative electrode current collector, a negative electrode active material layer, and a negative electrode non-coating portion. The negative electrode current collector is formed of a conductive metal material, for example, copper, to collect electrons from the negative electrode active material layer and move them to an external circuit. The negative electrode active material layer is prepared by mixing a negative electrode active material, a conductive material and a binder, and is formed by coating a predetermined thickness on the negative electrode current collector. The negative electrode non-coating portion is a portion in which a negative electrode active material layer is not formed in the negative electrode current collector, and the negative electrode tab 125 is welded to one side of the negative electrode non-coating portion.

The positive electrode tab 115 and the negative electrode tab 125 are respectively welded to the positive and negative electrode portions to serve to electrically connect the electrode assembly 100 and other portions of the battery. The positive electrode tab 115 and the negative electrode tab 125 are welded by resistance welding, and a lamination tape (not shown) may be further attached to the welding portion to prevent short and heat generation. However, the welding method of the positive electrode tab 115 and the negative electrode tab 125 is not limited thereto.

The separator 130 may be interposed between the positive electrode plate 110 and the negative electrode plate 120 and extend to surround the outer circumferential surface of the electrode assembly 100. The separator 130 is formed of a porous membrane polymer material to prevent short circuit between the positive electrode plate 110 and the negative electrode plate 120 and to allow lithium ions to pass therethrough.

The upper and lower insulating plates 160 and lower insulating plates 170 may be further included on the upper and lower portions of the electrode assembly 100 to prevent contact with the can 200 or the cap assembly 300, respectively.

The can 200 is formed in a cylindrical shape including a side plate 210 and a bottom plate 220. In addition, the can 200 includes a beading unit 230, a crimping unit 240, and a plurality of pressing units 250. The lower insulating plate 170, the electrode assembly 100, and the upper insulating plate 160 are sequentially inserted into the can 200, and an electrolyte (not shown) is injected.

The side plate 210 is formed to have a predetermined diameter so that a predetermined space in which the electrode assembly 100 can be accommodated is formed. An upper portion of the side plate 210 is opened to insert the electrode assembly 100 and an electrolyte (not shown).

The lower plate 220 is formed to seal a lower portion of the side plate 210. The negative electrode tab 125 of the electrode assembly 100 is bonded to the center of the lower plate 220, so that the can 200 itself serves as a negative electrode. In addition, the can 200 is generally formed of aluminum (Al), iron (Fe), or an alloy thereof.

The beading portion 230 is formed to protrude from the outside from the outside along the outer circumference of the can 200 between the electrode assembly 100 and the gasket 400, just above the upper insulating plate 160. Is formed. The beading part 230 may prevent the up and down flow of the electrode assembly 100.

The crimping unit 240 presses the upper portion of the cap assembly 300 coupled to the opening of the upper portion of the can 200 to press the upper portion of the can 200 by pressurizing to seal the battery. It is formed in the shape bent inward. The crimping unit 240 has a form surrounding the cap assembly 300 and the gasket 400 to closely contact the can 200, the cap assembly 300, and the gasket 400. Here, the crimping unit 240 may have a circular ring shape in a vertical section.

The plurality of pressing parts 250 are formed in a portion of the crimping part 240, that is, in the form of a groove which goes downward from the upper surface of the crimping part 240. Specifically, the plurality of pressing parts 250, the crimping unit 240 for the purpose of reducing the internal resistance of the battery by further strengthening the adhesion between the can 200, the cap assembly 300 and the gasket 400 Is formed by pressurization. The deeper the depth of the plurality of pressing parts 250 is, the more the adhesion between the can 200, the cap assembly 300, and the gasket 400 is enhanced. Therefore, even if external vibrations and shocks are applied to the secondary battery, the internal resistance of the battery is reduced since the flow between components inside the secondary battery is minimized. Referring to FIG. 3, the plurality of pressing units 250 may be symmetrically formed with respect to the central axis of the electrode assembly 100, and the distance between two neighboring pressing units may be formed to be constant. . This is to balance the adhesion between the can 200, the cap assembly 300, and the gasket 400.

The cap assembly 300 includes a safety vent 310, a current blocking means 320, a secondary protective element 330, and a cap up 340. The cap assembly 300 is coupled to the top opening of the can 200 to seal the can 200.

The safety vent 310 is located in the lower portion of the cap assembly 300 in the form of a plate, a protrusion 312 protruding downward in the center is formed. The protrusion 312 of the safety vent 310 is deformed upward by the pressure generated inside the secondary battery. The positive electrode tab 115 drawn from the positive electrode plate 110 and the negative electrode plate 120 of the electrode assembly 100, for example, the positive electrode plate 110, is welded to a predetermined surface of the lower surface of the safety vent 310. The safety vent 310 and the positive electrode plate 110 of the electrode assembly 100 are electrically connected. Here, in the remaining electrode plate, for example, the negative electrode plate 120 of the positive electrode plate 110 and the negative electrode plate 120, the negative electrode tab 125 drawn from the negative electrode plate 120 is welded to the bottom plate 220 of the can 200. It is electrically connected with the can 200. The safety vent 310 is deformed or ruptured when the pressure inside the can 200 rises, which serves to damage the current blocking means 320.

The current blocking means 320 is located above the safety vent 310, and breaks when the safety vent 310 is deformed to block the current.

The secondary protection element 330 is formed of, for example, a positive temperature coefficient (PTC) and positioned above the current blocking means 320. The positive temperature element serves to block current by rapidly decreasing the conductivity as the temperature of the secondary battery increases.

The cap up 340 is positioned above the secondary protection element 330 to cover the top of the battery and serves to provide a positive voltage or a negative voltage to the outside. The cap up 340 may further include a plurality of through holes 342 for gas discharge inside the battery.

The gasket 400 is installed between the can 200 and the cap assembly 300 to insulate the can 200 serving as the cathode and the cap assembly 300 serving as the anode. To this end, the gasket 400 is formed of an insulating material.

Next, a method of manufacturing a cylindrical secondary battery having the configuration as described above will be described.

4 is a flowchart illustrating a method of manufacturing a cylindrical secondary battery according to an embodiment of the present invention.

4, the method of manufacturing a cylindrical secondary battery according to an embodiment of the present invention, the electrode assembly and cap assembly forming step (S410), electrode assembly receiving step (S420), crimping unit forming step (S430), and pressurization Sub forming step (S440) is included.

First, in the electrode assembly and cap assembly manufacturing step (S410), the electrode assembly 100 is formed. The electrode assembly 100 is wound around the positive electrode plate 110, the negative electrode plate 120, and the separator 130 interposed between the positive electrode plate 110 and the negative electrode plate 120 in a circle, so-called 'jelly roll (Jelly Roll) 'Is formed in the form. The positive electrode plate 110 and the negative electrode plate 120 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 positive electrode plate 110 and the negative electrode plate 120 are wound, there is an uncoated portion in which a slurry is not applied at the beginning and the end of the current collector. The positive electrode tab 115 is provided at the non-coated portion of the positive electrode plate 110, and the negative electrode tab 125 is provided at the non-coated portion of the negative electrode plate 120. The positive electrode tab 115 may be formed to be upward in the opening direction of the can 200, and the negative electrode tab 125 may be formed to be pulled out of the negative electrode plate 120 downward, and both tabs 115 and 125 may be formed in the can 200. It may be formed to be drawn out upward in the direction of the opening of.

In addition, the cap assembly 300 is formed. As shown in FIG. 2, the cap assembly 300 includes a safety vent 310, a current blocking means 320, a secondary protective element 330, and a cap up 340 in order from the bottom. A safety vent 310 is located at the bottom of the cap assembly 300, and a central portion of the safety vent 310 has a protrusion 312 protruding downwardly and electrically connected to the positive electrode tab 115. Above the safety vent 310, a current interrupting device (CID) 320 is formed to break by protruding upward from the protrusion 312 of the safety vent 310 by an internal pressure. The secondary protection element 330, for example, a positive temperature element (PTC), is installed above the current blocking means 320. The positive temperature element is used to control the flow of current in the battery due to overheating of the battery. Block it. A cap up 340 having an electrode terminal convexly formed to be electrically connected to the outside is provided above the positive temperature element.

Next, in the electrode assembly accommodating step 420, the lower insulating plate 170 and the electrode assembly 100 are inserted into the can 200. The can 200 has a cylindrical shape as shown in FIG. 2, 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 plate 170 and the electrode assembly 100 are sequentially inserted into the can 200. In this case, a center pin may be inserted into an empty space in the center of the electrode assembly 100 to prevent loosening of the electrode assembly 100 and serve as a movement passage of the internal gas.

In addition, the negative electrode tab 125 is welded to the bottom plate 220 of the can 200. The negative electrode tab 125 drawn downward from the negative electrode plate 120 of the electrode assembly 100 is bent to be parallel to the lower surface of the electrode assembly 100 and welded to the lower plate 220 of the can 200. do. In this case, a lower insulating plate 170 is disposed between the portion of the negative electrode tab 125 and the lower surface of the electrode assembly 100 that are bent so that the lower surface of the electrode assembly 100 is not short-circuited with the lower plate 220 of the can 200. ).

Then, the upper insulating plate 160 is inserted into the can 200, and the beading part 230 is pressed inward from the outside along the outer circumference of the can 200 directly above the upper insulating plate 160. Form. The upper insulating plate 160 serves to insulate the upper surface of the electrode assembly 100 from the cap assembly 300, and the beading portion 230 flows in the can assembly 200 in the can 200. Serves to prevent.

Then, an electrolyte is injected into the can 200. The electrolyte serves to move lithium ions generated by the electrochemical reaction in the electrode plates 110 and 120 during charging and discharging.

The gasket 400 is inserted into the can 200 to be seated on the beading part 230. The gasket 400 is made of an insulating material to insulate between the can 200 and the cap assembly 300, and is made of an elastic material to help seal the battery in the subsequent crimping process.

Then, the positive electrode tab 115 is welded to one component of the cap assembly 300. Referring to FIG. 2, the positive electrode tab 115 is welded to the protrusion 312 of the safety vent 310.

Next, in the step of forming a crimping unit (S430), the cap assembly 300 is seated on the gasket 400 and a crimping process is performed using a crimping jig. The crimping process is a bending process of sealing the can 200 by applying pressure to the opening wall of the can 200 inwardly and downwardly with a cap up 340 introduced into the gasket 400 inside the cap 200. As an operation, according to this process, as shown in FIG. 2, a crimping portion 240 is formed to be bent into the can at the top of the can to surround the cap assembly 300 and the gasket 400. Accordingly, the can 200, the cap assembly 300, and the gasket 400 are sealed between each other.

Next, in the pressing unit forming step (S440), a part of the crimping unit 240 is pressed second. The second pressurization may be performed downward from the upper surface of the crimping unit 240, and further enhances adhesion between the can 200, the cap assembly 300, and the gasket 400. As a result of the second pressing, a plurality of pressing parts 250 may be formed in a part of the crimping part 240 as shown in FIGS. 2 and 3. The plurality of pressing units 250 may be formed by pressing a portion of the crimping unit 240 with protrusions formed on the crimping jig. The second pressurization may be after the first pressurization. Referring to FIG. 2, the plurality of pressing parts 250 are formed in the shape of a groove that enters downward from an upper surface of the crimping part 240. The deeper the depth of the plurality of pressing parts 250 is, the more tightly the adhesion between the components of the cap assembly 300. Therefore, even if external vibrations and shocks are applied to the secondary battery, the internal resistance of the battery is reduced since the flow between components inside the secondary battery is minimized. Here, it is necessary that the end of the crimping unit 240 does not face upward and does not lift upward.

Referring to FIG. 3, the crimping unit 240 has a circular ring shape in a vertical cross section, and four pressing units 250 are symmetrically formed with respect to the central axis of the electrode assembly 100. However, the present invention does not limit the number of the pressing portion.

In addition, it is preferable that the distance between two neighboring pressing units among the plurality of pressing units 250 is constant. If three pressing portions are formed, an arrangement of equilateral triangles in which the pressing portions each form a vertex is preferable in view of the balance of adhesion force.

Then, a pressing process is performed to press the upper part of the battery to meet the height of the standard, and then a tubing operation is performed to coat the exterior of the battery, thereby completing the battery.

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.

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

2 is a front sectional view of a cylindrical secondary battery according to an embodiment of the present invention.

3 is a plan view of the cylindrical secondary battery illustrated in FIG. 2.

4 is a flowchart illustrating a method of manufacturing a cylindrical secondary battery according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100 electrode assembly 200 can

230: beading unit 240: crimping unit

250: pressurization portion 300: cap assembly

400: gasket 500: cylindrical secondary battery

Claims (12)

A secondary battery comprising an electrode assembly, a can housing the electrode assembly, a cap assembly closing an open top of the can, and a gasket positioned between the open top of the can and the cap assembly, The can A crimping portion formed in a shape bent inward from an upper end, It includes a plurality of pressing portion formed in the form of a groove that goes down from the upper surface of the crimping portion, The plurality of pressing portions are formed symmetrically with respect to the central axis of the electrode assembly, the secondary battery, characterized in that the distance between two adjacent pressing portion of the plurality of pressing portions. delete The method of claim 1, The crimping portion is a secondary battery, characterized in that the vertical cross-section of the circular ring shape. delete delete The method of claim 1, The can further comprises a beading portion projecting from the outside inward along the outer periphery of the portion between the electrode assembly and the gasket. The method of claim 1, Secondary battery, characterized in that the outer shape of the electrode assembly and the can is cylindrical. Manufacturing an electrode assembly and a cap assembly; Receiving the electrode assembly in a can; Positioning a gasket between the open top of the can and the cap assembly, and first pressing the top of the can to form a crimping portion to seal between the can, the gasket, and the cap assembly; And And pressing a portion of the crimping portion to form a plurality of pressing portions, The second pressing is a manufacturing method of a secondary battery, characterized in that the lower side is made from the top of the crimping portion. The method of claim 8, The second pressing is a manufacturing method of a secondary battery, characterized in that by the crimping jig (crimping jig) formed with a projection. The method of claim 8, And the second pressurization is performed after the first pressurization. delete The method of claim 8, Receiving the electrode assembly in a can And forming a beading part by pressing from the outside inward along the outer circumference of the portion between the electrode assembly and the gasket in the can.

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