KR20060088312A - Cap assembly and lithium ion secondary battery with the same - Google Patents

Abstract

The present invention relates to a lithium ion secondary battery, and more particularly, to a cap assembly having an improved structure so as to prevent short generation during pack operation of a battery, and a lithium ion secondary battery employing the same.

According to the lithium ion secondary battery according to the present invention, a step is formed in a cap plate at a position where an electrolyte injection hole is formed, and the UV curing agent portion formed after sealing the electrolyte injection hole does not protrude to the outside of the cap plate, thereby eliminating the need for a washer. The hole can be removed. Accordingly, it is possible to prevent contact between the lid on the washer and the UV curing agent portion on the cap plate during pack operation of the battery, thereby preventing short circuit of the battery during pack operation, thereby improving safety of the battery.

Description

Cap assembly and Lithium ion secondary battery having the same {Cap Assembly and Lithium ion Secondary Battery with the same}

1 is a cross-sectional view showing a conventional lithium ion secondary battery cut.

Figure 2 is a cross-sectional view showing the lithium ion secondary battery according to the present invention cut.

3 is a cross-sectional view of the cap plate and the washer according to an embodiment of the present invention.

Figure 4 is a cross-sectional view of the cap plate and the washer according to another embodiment of the present invention.

<Brief description of symbols for the main parts of the drawings>

310, 310a ... Cap plate 312 ... Electrolyte inlet

360 ... ball 360a ... sealing pin

420 ... Protection circuit 430, 430a ... UV curing agent

440 Washer 450 Support

460 ... step

The present invention relates to a lithium ion secondary battery, and more particularly, to a cap assembly having an improved structure so as to prevent short generation during pack operation of a battery, and a lithium ion secondary battery employing the same.

In general, the secondary battery refers to a battery that can be charged and discharged, unlike a primary battery that is not rechargeable, and can be miniaturized and large in capacity. Typically, nickel-hydrogen (Ni-MH) batteries, lithium (Li) batteries, and lithium ion (Li-ion) batteries are used. Recently developed lithium secondary batteries are widely used in advanced electronic devices such as cellular phones and notebook computers.

The secondary battery is classified into a liquid electrolyte battery and a polymer electrolyte battery according to the type of electrolyte. A battery using a liquid electrolyte is called a lithium ion battery, and a battery using a polymer electrolyte is called a lithium polymer battery. In addition, secondary batteries are manufactured in various shapes, and typical shapes include cylindrical shapes, square shapes, and pouch types.

1 illustrates a general rectangular lithium ion secondary battery.

Referring to FIG. 1, a secondary battery generally includes a can 11, a cap assembly 100 coupled to an electrode assembly 12 accommodated inside the can 11, and an upper opening of the can 11. And a lead 200 for electrically connecting the first or second electrode terminal 120 to the protection circuit 220 and a washer 240 coupled to the cap plate.

The can 11 is a metal container having a shape in which a top is opened in a rectangular parallelepiped in a rectangular lithium ion secondary battery, and formed by a processing method such as deep drawing. The can 11 is a container of an electrode assembly 12 and an electrolyte consisting of a first electrode plate 13, a separator 14, and a second electrode plate 15, and the electrode assembly 12 is a can 11. The top opening is sealed by the cap assembly 100 after being inserted through its open top, ie the top opening.

The cap assembly 100 is provided with a flat cap plate 110 having a size and shape corresponding to the top opening of the can 11. A terminal through hole 111 is formed in the center portion of the cap plate 110 to allow the electrode terminal to pass therethrough, and a first outside the first or second electrode terminal 120 penetrating the center portion of the cap plate 110. Alternatively, a tube-shaped gasket 130 is installed to electrically insulate the second electrode terminal 120 from the cap plate 110. The insulating plate 140 is disposed at the lower surface of the cap plate 110 near the terminal through hole 111 of the cap plate 110, and the terminal plate is energized with the electrode terminal 120 at the lower surface of the insulating plate 140. 150 is provided.

In addition, the cap plate 110 is provided with a safety vent 190 to discharge the gas when the internal pressure rises to reach a predetermined pressure or more, one side passage for injecting the electrolyte into the can 11 An electrolyte injection hole 112 is provided.

The electrolyte injection hole 112 press-fits the ball 160 by pressing means such as a press to seal the ball 160, the ball 160 is pressed with the cap plate 110 to prevent leakage of the electrolyte after pressing the ball It is welded along the boundary by laser welding or the like. An ultraviolet curing agent is coated on the indented ball 160 and then cured at an appropriate temperature to form an ultraviolet curing agent 230 so as to prevent leakage of the electrolyte solution.

A washer for insulating the lead 200 connected to the first or second electrode terminal 120 from the cap plate 110 connected to the first or second electrode tab 17 on the cap plate 110. 240 is provided.

Since the washer 240 is located above the cap plate 110, contact with the ultraviolet curing agent 230 formed on the upper side of the ball 160 of the electrolyte injection hole 112 may occur, so as to prevent the washer ( The hole 261 is formed in 240.

However, the hole 261 formed in the washer 240 is open so that the lead 200 positioned on the washer 240 may come into contact with the ultraviolet curing agent 230 formed on the electrolyte injection hole 112. In particular, the battery may be shorted through the hole 261 during the pack operation of the battery, thereby reducing the safety of the battery.

The present invention relates to a lithium ion secondary battery, and more particularly to a lithium ion secondary battery employing a cap assembly having an improved structure to prevent the occurrence of short when the battery pack operation.

In order to achieve the above object, the present invention, at least a terminal through the cap assembly having a cap plate formed with an electrolyte injection hole on one side, the cap plate is characterized in that the step is wider than the electrolyte injection hole.

In addition, the lithium ion secondary battery according to the present invention accommodates the wound electrode assembly and the electrode assembly having a separator interposed between the first electrode plate, the second electrode plate, the first electrode plate and the second electrode plate. And a cap assembly installed at an upper portion of the case, the cap assembly including a cap plate having at least a terminal through-hole and an electrolyte injection hole, wherein the electrolyte injection hole has a wide step at an upper side thereof. do.

Hereinafter, a lithium secondary battery according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a cross-sectional view showing a portion of the lithium ion secondary battery according to the present invention cut away. Figure 3 shows a cross-sectional view of the cap plate and washer according to an embodiment of the present invention, Figure 5 shows a cross-sectional view of the cap plate and washer according to another embodiment of the present invention.

2 and 3, the lithium ion secondary battery 30 is coupled to the can 31, an electrode assembly 32 accommodated in the can 31, and an upper end opening of the can 31. And a lid 400 for electrically connecting the cap assembly 300 and the first electrode or the second electrode terminal to the protection circuit 420, and a washer 440 positioned above the cap plate 310.

The electrode assembly 32 is formed by winding a separator 34 between the first electrode 33 and the second electrode 35. The first electrode 33 is electrically connected to the cap plate 310 through the first electrode tab 36, and the second electrode 35 is connected to the cap plate 310 through the second electrode tab 37. The second electrode terminal 320 is electrically connected to the formed second electrode terminal 320, and the second electrode terminal 320 is insulated from the cap plate 310 by the gasket 330 and the insulating plate 340.

The can 31 may be formed of an iron material, but if the can 31 is formed of aluminum or an aluminum alloy, light weight of the battery may be reduced due to the light property of aluminum, and may not be corroded even when used for a long time under high voltage. The can 31 is a container of an electrode assembly 32 composed of the first electrode 33, the separator 34, and the second electrode 35 and an electrolyte (not shown), and the electrode assembly 32 is a can ( 31, the top opening is sealed by the cap assembly 300 after being inserted through the open top, ie the top opening.

The cap assembly 300 is provided with a flat cap plate 310 having a size and shape corresponding to the top opening of the can 31. The terminal hole 311 is formed in the center portion of the cap plate 310 so that the electrode terminal 320 can pass therethrough.

A tubular gasket 330 is installed outside the second electrode terminal 320 penetrating the central portion of the cap plate 310 to electrically insulate the second electrode terminal 320 and the cap plate 310. The insulating plate 340 is disposed in the lower surface of the cap plate 310 near the terminal through hole 311 of the cap plate 310, and the lower surface of the insulating plate 340 is energized with the first electrode terminal 320. The terminal plate 350 is provided.

In addition, the cap plate 310 is formed with a safety vent 390 to allow the gas to be released when the internal pressure rises to reach a predetermined pressure or more. In addition, an electrolyte injection hole 312 is provided at one side of the cap plate 310 to provide a passage for injecting the electrolyte into the can 31.

In addition, the second electrode terminal 320 is connected to the lead 400, and the lead 400 is soldered on the substrate of the protection circuit 420 to be electrically connected to the electrode assembly 32. The protection circuit 420 controls overcharge voltage and current, overdischarge voltage and current, and a short of the electrode assembly 32, and is installed in a predetermined region of the lithium ion secondary battery can 31. The lead 400 needs to be insulated from the cap plate 310 connected to the first electrode 33. Accordingly, a washer 440 formed of an insulator is provided on the cap plate 310.

In order to stably position the washer 440 on the cap plate 310, a predetermined space is required between the washer 440 and the cap plate 310. That is, the washer 440 is provided with a support 450, and the washer support 450 caps the washer 440 while securing a predetermined space between the washer 440 and the cap plate 310. To be stably positioned on the plate 310. The washer support 450 may use an elastic material such as a sponge, and may be formed at predetermined intervals.

The electrolyte injection hole 312 is sealed by the ball 360, the ball 360 is pressed into the pressing means, such as a press for lifting and lowering the boundary where the ball 360 is pressed against the cap plate 310 The ball 360 is sealed by welding such as a laser along a portion. In addition, in order to prevent leakage of the electrolyte after laser welding, an ultraviolet curing agent may be coated on the upper side of the ball 360 and then cured at an appropriate temperature to form an ultraviolet curing agent 430 to prevent electrolyte leakage.

A step 460 is formed in the cap plate 310 in an outer direction of the upper portion of the electrolyte injection hole 312, so that the UV curing agent 430 formed on the upper side of the ball 360 moves out of the cap plate 310. Does not protrude Therefore, there is no hole 261 in the washer 440 to prevent contact with the ultraviolet curing agent 430, and there is no problem that the ultraviolet curing agent 430 is exposed to the outside of the cap plate 310 during the pack operation. .

That is, the washer 440 has no open hole 261 formed in the conventional washer 240, so that the lid 400 and the cap plate 310 positioned above the washer 440 during the pack operation of the battery. There is no fear that contact with the UV curing agent portion 430 formed in the battery cell may occur, and a short circuit of the battery does not occur.

Referring to FIG. 4, the electrolyte injection hole 312 is formed with a step 460 having a wide upper side, and the electrolyte injection hole 312 is sealed by fitting a sealing pin 360a rather than a method of press-fitting a ball. . An upper surface of the sealing pin 360a forms a horizontal plane with a cap plate 310a surface on which the electrolyte injection hole 312 is formed, and laser welding along a boundary portion where the sealing pin 360a and the cap plate 310a meet. Sealed.

After sealing the electrolyte injection hole 312 by a method such as laser welding, in order to prevent leakage of the electrolyte secondary coating an ultraviolet curing agent on the sealing pin (360a) and then curing it at an appropriate temperature UV curing agent part ( 430a is formed to completely seal the electrolyte injection hole 312.

The ultraviolet curing agent 430a formed on the sealing pin 360a is formed in the step 460 formed on the cap plate 310a and does not protrude out of the cap plate 310a. Short with the lead 400 located in the upper portion can be prevented.

Next, the operation of the lithium ion secondary battery according to the present invention will be described.

The electrolyte injection hole 312 formed in the cap plate 310 is formed with a step 460 having a wide upper side, and the UV curing agent part 430 formed after sealing the electrolyte injection hole 312 is the cap plate 310. As it does not protrude to the outside, the cap plate 310 is not in contact with the washer 440 located above. Accordingly, the washer 440 does not form a hole for preventing contact with the UV curing agent 430.

That is, since there is no hole in the washer 440, there is no fear that the lead 400 positioned on the washer 440 and the ultraviolet curing agent 430 positioned on the cap plate 310 are in contact with each other, Short between the lid 400 and the cap plate 310 can be prevented.

As described above, the present invention is not limited to the specific preferred embodiments described above, and any person having ordinary knowledge in the technical field to which the present invention belongs 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.

According to the lithium ion secondary battery according to the present invention, a step is formed in a cap plate at a position where an electrolyte injection hole is formed, and the UV curing agent portion formed after sealing the electrolyte injection hole does not protrude to the outside of the cap plate, thereby eliminating the need for a washer. The hole can be removed. Accordingly, it is possible to prevent contact between the lid on the washer and the UV curing agent portion on the cap plate during pack operation of the battery, thereby preventing short circuit of the battery during pack operation, thereby improving safety of the battery.

Claims (10)

In the cap assembly having at least a terminal hole and a cap plate formed with an electrolyte injection hole on one side, Cap assembly, characterized in that the step is formed in the cap plate is wide the upper side of the electrolyte injection hole. The method of claim 1, The electrolyte injection hole is cap assembly characterized in that the ball is pressed and sealed after welding. The method of claim 2, Cap assembly, characterized in that the UV curing agent portion is further formed on the ball. The method of claim 1, The electrolyte injection hole is cap assembly, characterized in that the sealing is fixed by sealing pins. The method of claim 4, wherein Cap assembly, characterized in that the UV curing agent portion is further formed on the sealing pin. A wound electrode assembly having a first electrode plate, a second electrode plate, a separator interposed between the first electrode plate and the second electrode plate; A case having a space for accommodating the electrode assembly; A cap assembly installed on an upper portion of the case and including a cap plate having at least a terminal through-hole and an electrolyte injection hole formed therein; The electrolyte injection hole is a lithium ion secondary battery, characterized in that the step is formed in the upper wide. The method of claim 6, The electrolyte injection hole is a lithium ion secondary battery, characterized in that the welding is fixed after sealing by injecting the ball. The method of claim 7, wherein The lithium ion secondary battery, characterized in that the UV curing agent portion is further formed on the ball. The method of claim 6, The electrolyte injection hole is sealed with a sealing pin, the lithium ion secondary battery, characterized in that the welding is fixed. The method of claim 9, Lithium ion secondary battery, characterized in that the UV curing agent portion is further formed on the sealing pin.

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