KR100601532B1 - Secondary battery - Google Patents

Abstract

The secondary battery of the present invention includes a case in which an electrode assembly into which the first and second electrode tabs are drawn, and an upper portion of the case are covered and sealed, a safety vent is formed at one side, and an electrolyte injection hole is formed at the other side thereof. And a terminal plate coupled to the bottom surface of the cap plate and the insulating plate provided with safety means to prevent rotation of the cap plate, and the cap plate and the terminal plate are prevented from being contacted and shorted. have.

Secondary Battery, Cap Plate, Insulation Plate, Terminal Plate, Cap Assembly

Description

Secondary Battery {SECONDARY BATTERY}

1 is an exploded perspective view of a rechargeable battery according to the present invention;

2 is a partial cross-sectional view of a secondary battery according to the present invention;

3 is a front view showing a cap plate according to the present invention.

<Brief Description of Major Codes in Drawings>

100 cap assembly 110 cap plate

111: first terminal through hole 113: electrolyte injection hole

115: stopper 120: gasket

130: electrode terminal 140: insulation plate

141: second terminal through hole 143: electrolyte injection hole

150: terminal plate 151: third terminal through

160: insulation case 163: first through hole

165: second through hole 200: case

210: first electrode plate 215: first electrode tab

220: second electrode plate 225: second electrode tab

250: electrode assembly

The present invention relates to a secondary battery, and more particularly, to a secondary battery that suppresses the explosion due to pressurization.

Recently, compact and lightweight electric / electronic devices such as cellular phones, notebook computers, camcorders, etc. have been actively developed and produced. These portable electric / electronic devices have a battery pack that can be operated in a place where no separate power source is provided. The built-in battery pack includes at least one battery therein for outputting a predetermined level of voltage for driving the portable electric / electronic device for a period of time.

In view of economical aspects, the battery pack employs a secondary battery capable of charging and discharging. Typical secondary batteries include nickel-cadmium (Ni-Cd) batteries, nickel-hydrogen (Ni-MH) batteries, and lithium secondary batteries such as lithium (Li) batteries and lithium ion (Li-ion) batteries.

In particular, the lithium secondary battery has an operating voltage of 3.6 V, which is three times higher than that of a nickel-cadmium battery or a nickel-hydrogen battery, which is widely used as a power source for portable electronic equipment, and is rapidly increasing in terms of high energy density per unit weight. to be.

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

In general, a secondary battery includes a first and second electrode plates coated with an active material, and a separator positioned between the first and second electrode plates to prevent shorting and to allow only movement of lithium ions (Li-ion). And a wound electrode assembly, a case accommodating the electrode assembly, an electrolyte injected into the case to allow movement of lithium ions, a cap assembly for sealing the case, and the like.

The secondary battery stacks first and second electrode plates and separators from which the first and second electrode tabs are drawn from the first and second electrode plates, and then winds them up to manufacture an electrode assembly.

Here, the first electrode tab of the electrode assembly is connected to the cap plate of the cap assembly to be described later, the second electrode tab is connected to the electrode terminal inserted into the cap assembly has a different polarity.

The cap assembly is assembled to the case and seals the case, the gasket to insulate the cap plate and the electrode terminal is installed between the electrode terminal and the cap plate and the electrode terminal connected to the electrode tab and the electrode terminal to insulate the cap plate and the electrode tab An insulation plate and a terminal plate coupled to the lower side of the insulation plate and connected to the electrode terminal are provided.

Here, one side of the cap plate is formed with an electrolyte injection hole which injects the electrolyte and is sealed by a bowl, and the other side is opened when the pressure inside the case is increased to form a safety vent to prevent explosion.

However, in the conventional secondary battery, when the cap assembly is pressed in order to proceed with the assembly process of coupling the cap assembly closing the case to the case, the insulating plate is deformed and rotated so that the cap plate and the terminal plate may be contacted and short-circuited. There is a problem.

That is, since the cap plate is connected to the first electrode tab and the electrode terminal is connected to the second electrode tab to the terminal plate, the insulating plate has a function of insulating between the cap plate and the terminal plate having different polarities. However, when the insulation plate is bent and rotated by pressing, the insulation may be shorted between the cap plate and the terminal plate.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a secondary battery which prevents the insulating plate from rotating during the assembling process or use of the secondary battery.

The present invention for achieving the above object is a case housing the electrode assembly with the first and second electrode tabs drawn out to the upper side, and cover and seal the top of the case and a safety vent is formed on one side and the other side Provided is a secondary battery including a cap plate having an electrolyte injection hole, an insulation plate provided with safety means to prevent rotation and being coupled to a bottom surface of the cap plate, and a terminal plate coupled to a bottom surface of the insulation plate.

The safety means is formed to extend the length of the insulating plate to cover the lower side of the electrolyte inlet, the electrolyte injection hole formed in communication with the electrolyte injection hole on one side and a pin-shaped plug to cover the electrolyte injection hole and the electrolyte injection hole Is preferred.

Preferably, the second electrode tab is in contact with a bottom surface of the cap plate side at which the safety vent is located.

The second electrode tab is preferably provided at a predetermined distance from the safety vent.

Preferably, the distance between the second electrode tab and the safety vent is at least 1 mm.

Preferably, the second electrode tab is an anode.

Hereinafter, with reference to the drawings will be described in detail an embodiment according to the present invention.

1 is an exploded perspective view of a secondary battery according to the present invention, Figure 2 is a partial cross-sectional view of the secondary battery according to the present invention, Figure 3 is a front view showing a cap plate according to the present invention. As shown in these drawings, the secondary battery has a case 200 having one side opened, an electrode assembly 250 accommodated in the case 200, and a cap coupled to the opening 201 of the case 200. The cap assembly 100 includes a plate 110 and a safety means for preventing movement of the cap assembly 100.

Since the case 200 is formed in a substantially rectangular box shape and one side is opened and is formed of a metal material, the case 200 itself may serve as a terminal. As the material forming the case 200, an iron or stainless steel is also used, but an aluminum or aluminum alloy having excellent corrosion resistance so as to easily cope with corrosion while being a lightweight conductive metal is preferred. However, the material is not limited to this embodiment.

The electrode assembly 250 is wound around a separator 230 interposed between the first electrode 210 to which the first electrode tab 215 is attached and the second electrode 220 to which the second electrode tab 225 is attached. Jelly-roll type. The first and second electrode tabs 215 and 225 are led out of the electrode assembly 250.

The cap assembly 100 includes a cap plate 110, an insulation plate 140, a terminal plate 150, and an electrode terminal 130.

The cap plate 110 is formed of a metal plate having a size and a shape corresponding to the opening 201 of the case 200, and a first terminal through hole 111 into which the electrode terminal 130 is inserted is formed. In addition, an electrolyte injection hole 113 for injecting an electrolyte is formed at one side of the central portion of the cap plate 110, and a safety vent 117 is formed at the other side.

The safety vent 117 forms a groove of a certain depth so that the pressure bursts at a pressure lower than the dangerous level when the pressure inside the battery rises or explodes, thereby thinning or forming a hole to weld a thin plate to the hole. It is prepared by.

After the cap assembly 100 is assembled to the opening 201 of the case 200, the electrolyte injection hole 113 is a passage for injecting the electrolyte and is sealed with a stopper 115.

The electrode terminal 130 is connected to the first electrode tab 215 or the second electrode tab 225 to act as a negative electrode or a positive electrode terminal. When the electrode terminal 130 is inserted into the first terminal hole 111, a tubular gasket 120 is coupled to the outer surface of the electrode terminal 130 to insulate the electrode terminal 130 from the cap plate 110. Is inserted. Here, the electrode terminal 130 is preferably a cathode.

The insulating plate 140 is formed of an insulating material such as the gasket 120 and is coupled to the lower surface of the cap plate 110. The insulating plate 140 has a second terminal through hole 141 formed at a position corresponding to the first terminal through hole 111 of the cap plate 110. In addition, as a safety means for preventing the rotation of the insulating plate 140, the insulating plate 140 is formed to extend to cover the electrolyte injection opening 113 of the cap plate 110, the extended insulating plate 140 to the cap An electrolyte injection hole 143 is formed at a position corresponding to the electrolyte injection hole 113 of the plate 110.

At this time, the stopper 115 blocking the electrolyte injection port 113 should be formed so that its length is extended to cover the above-described electrolyte injection hole 143 in a pin shape.

The terminal plate 150 is formed of Ni metal or an alloy thereof, and is coupled to the lower surface of the insulating plate 140. The terminal plate 150 has a third terminal through hole 151 into which the electrode terminal 130 is inserted at a position corresponding to the first terminal through hole 111 of the cap plate 110. Thus, the electrode terminal 130 is electrically insulated from the cap plate 110 by the gasket 120 and electrically connected to the terminal plate 150.

Meanwhile, first and second through holes 163 and 165 penetrating the first and second electrode tabs 215 and 225 to electrically insulate the electrode assembly 250 and the cap assembly 100 are formed on the upper surface of the electrode assembly 250. The insulating case 160 covering the top of the electrode assembly 250 is installed.

The first and second electrode tabs 215 and 225 penetrating the insulating case 160 may have polarities of a cathode and an anode, respectively.

That is, since the first electrode tab 215 is a cathode and is connected to the terminal plate 150, the terminal plate 150 and the electrode terminal 130 connected to the terminal plate 150 become a cathode and the second electrode tab ( 225 is an anode, and the cap plate 110 and the case 200 become anodes because they contact the bottom surface of the cap plate 110.

In this case, it is preferable that the second electrode tab 225 serving as the anode is welded to the bottom surface of the cap plate 110 in which the safety vent 117 is positioned based on the center of the cap plate 110. In addition, the second electrode tab 225 is disposed so that the distance between the safety vent 117 and the safety vent 117 is at least 1 mm so as not to be welded to the bottom surface of the safety vent 117 having a relatively thin thickness.

Hereinafter, the operation of the secondary battery according to the present invention having such a configuration will be described.

First, the electrode assembly 250 from which the first and second electrode tabs 215 and 225 are drawn out is received in the case 200.

Next, the cap assembly 100 is assembled.

An insulating case 160 penetrating the first and second electrode tabs 215 and 225 of the electrode assembly 250 is mounted on the upper side of the electrode assembly 250 through the first and second through holes 163 and 165.

Meanwhile, the electrode terminal 130 is inserted into the gasket 120 and then inserted into the first terminal through hole 111 of the cap plate 110.

Next, the electrode plate 130 is inserted into the second terminal through-hole 141 located in the center of the insulating plate 140. In addition, it is coupled to the bottom surface of the cap plate 110 is installed in communication with the electrolyte injection hole 143 and the electrolyte injection hole 111 of the cap plate 110 formed in the extended position.

Next, the terminal plate 150 is coupled to the bottom surface of the insulating plate 140 and the electrode terminal 130 is inserted into the third terminal through hole 151 to be connected to the electrode terminal 130.

Next, the pin-shaped plug 115 formed to extend downward is inserted to cover both the electrolyte injection hole 113 and the electrolyte injection hole 143.

The cap assembly 100 assembled as described above is coupled to the opening 201 of the case 200.

The first electrode tab 215 penetrating through the first through hole 163 of the insulating case 160 is in contact with the terminal plate 150 connected to the electrode terminal 130.

In this case, the cap plate 110 is assembled such that the side where the safety vent 117 is positioned based on the first terminal through-hole 111 is in contact with the second electrode tab 225.

That is, the terminal plate 150 coupled with the electrode terminal 130 serving as the cathode is formed to extend in the opposite direction to the safety vent 117, thereby reducing the possibility of contact with the second electrode tab 225.

In addition, even when the cap assembly 100 coupled to the opening 201 of the case 200 is pressed, the insulating plate 140 and the terminal plate 150 are fixed to the cap plate 110 by the stopper 115. Therefore, the insulation plate 140 and the terminal plate 150 cannot be rotated.

According to the present invention, the secondary battery has an advantage that the cap plate and the terminal plate are prevented from being shorted because the insulating plate is not rotated by the safety means even when the cap assembly is pressed to couple the cap assembly to the case. .

In addition, since the second electrode tab is installed adjacent to the safety vent, the second electrode tab and the terminal plate are prevented from being shorted by contacting the terminal plate even when the safety vent having a relatively thin thickness is broken by maintaining a predetermined distance from the terminal plate. There is this.

In addition, the secondary battery has an advantage of preventing a safety accident such as an explosion due to a short circuit.

Claims (6)

A case accommodating an electrode assembly in which the first and second electrode tabs are drawn upward; A cap plate covering and sealing the upper portion of the case and having a safety vent formed on one side and an electrolyte injection hole formed on the other side; An insulating plate coupled to the bottom of the cap plate and provided with safety means to prevent rotation; And And a terminal plate coupled to a bottom surface of the insulating plate. The safety means is formed so that the length of the insulating plate extends to cover the lower side of the electrolyte inlet and the electrolyte injection hole formed in communication with the electrolyte injection hole on one side, the pin-shaped plug to cover the electrolyte injection hole and the electrolyte injection hole Secondary battery comprising a. delete The method of claim 1, And the second electrode tab is in contact with a bottom surface of the cap plate side at which the safety vent is located. The method of claim 1, The second electrode tab is a secondary battery, characterized in that installed at a predetermined distance from the safety vent. The method of claim 1, The distance between the second electrode tab and the safety vent is at least 1mm or more secondary battery. The method of claim 1, The second electrode tab is a secondary battery, characterized in that the positive electrode.

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