KR100346387B1 - Safety apparatus used in secondary battery - Google Patents

Abstract

Disclosed is a safety device for a secondary battery. The present invention relates to a safety device of a secondary battery that blocks the flow of current to prevent the internal pressure rise due to abnormal operation or overcharging of the battery and prevents heat generation and explosion, and in particular, the operating pressure is easily and accurately set, Ensure safety and reliability. The present invention provides a safety device for a secondary battery formed by stacking a current blocking disk, an insulation, and a safety plate in an upper opening of a can, the current blocking disk having a plurality of vent holes, and a variable part connected to the current blocking disk. And a coupler fastened through the current blocking disk and the variable portion, wherein the variable portion is expanded by the internal pressure when the internal pressure rises, and shorted from the current blocking disk to block the current. According to the present invention, by combining the safety plate and the current blocking disk with a rivet rather than a welding method, it is possible to operate precisely at the set operating pressure, thereby ensuring safety against abnormal operation and explosion of the battery, Reliability can be secured.

Description

Safety apparatus used in secondary battery

The present invention relates to a secondary battery, and in particular, when the pressure inside the battery rises above the specified pressure, it can block the flow of current and release the internal gas to the outside to prevent explosion to ensure the safety of the battery It relates to a safety device of a secondary battery.

Rechargeable batteries can be recharged, miniaturized, and large-capacity, and are representative of nickel hydrogen (Ni-MH) batteries, lithium (Li) batteries, and lithium ion (Li-ion) batteries.

Lithium-ion batteries, which are well known as secondary batteries, use lithium-transition metal oxides as positive electrode active materials, carbon or carbon complexes as negative electrode active materials, and inject a liquid electrolyte in which lithium salt is dissolved in an organic solvent, thereby providing a positive electrode. Lithium ions are moved between the negative electrode and the negative electrode to generate an electromotive force so that charge and discharge are performed.

4 shows a lithium ion battery having a conventionally known spiral-wound electrode portion. The electrode part 2 wound together with the positive electrode and the negative electrode is housed inside the can 4 connected with the negative electrode together with the liquid electrolyte, and the upper part of the can 4 is insulated through the gasket 6 and the The cap assembly 8 which connects with a positive electrode is provided.

The cap assembly 8 is laminated from the top in the order of the cap cover 10, the current limiter 12, and the safety plate 14, and the lower part of the safety plate 14 is interposed with an insulator 16. 16) The current blocking disk 18 is attached to the lower part, and the upper part of the can 4 is assembled and sealed by crimping and other methods. The current blocking disk 18 is welded with the positive electrode tab 20 before assembly for connection with the positive electrode.

The lithium ion battery configured as described above may decompose the liquid electrolyte at the positive electrode during the abnormal operation or overload of the battery, and may precipitate due to the deposition of lithium metal at the negative electrode.At this time, the internal pressure rises above the prescribed pressure, causing the risk of heat generation and explosion. Will accompany.

For this reason, in the related art, the safety plate 14 is formed by forming a groove 14A having a constant depth or mechanically etched by a mechanical method or an etching method, or relatively weakly deformed, so that when the pressure inside the battery rises above the specified pressure, the current is first. By debonding the welding disk with the blocking disk 18 and also causing the groove 14A and the weakened portion to break, it blocks the flow of current and reduces the internal pressure to prevent explosion.

However, in the safety device so far, the safety plate 14 and the current blocking disk 18 are coupled by mutual welding, and the working pressure is determined by the welding force, so that it is difficult to accurately match the operating pressure. In particular, there was a problem that the risk of explosion of the battery during malfunction.

In addition, the welding plate of the safety plate 14 and the current blocking disk 18 by the impact applied to the battery has a disadvantage that the battery can not be used.

The present invention was devised to solve the above problems, so that the operating pressure of the safety plate and the current blocking disk is always kept constant without being influenced by the influence of the assembling process or material, and ultimately the abnormal operation of the battery. It is an object of the present invention to provide a safety device for a secondary battery that can secure safety against explosions and improve reliability against external shocks such as drops.

1 is a cross-sectional view showing the configuration of a cap assembly according to the present invention,

2 is an exploded perspective view of a safety plate and a current blocking disk according to the present invention;

Figure 3a, 3b, 3c is an operating state of the safety device according to the present invention,

4 is a cross-sectional view showing the configuration of a cap assembly of the prior art.

<Description of the symbols for the main parts of the drawings>

12: current limiter 100: safety plate

100A: Variable part 100B, 140A: Hole

140: current blocking disk 140B: air vent

160: Coupler

In order to achieve the above object, the safety device of a secondary battery according to an aspect of the present invention includes an electrode part in which a positive electrode, a negative electrode, and a separator are wound together, together with a liquid electrolyte, into the can, and the upper opening of the can. Sealing is installed through the gasket, the current blocking disk, the insulator, the safety plate and the current limiter from the bottom, laminated in the order of the cap cover formed with a hole in the upper limit of the current limiter, the current blocking disk having a plurality of vents and And a safety plate having a variable portion connected to the current blocking disk, and a coupler for fastening through the current blocking disk and the variable portion, wherein the variable portion expands by internal pressure when the internal pressure increases, and is shorted from the current blocking disk. Configure to cut off the current.

Notches are formed on both bottom surfaces of the safety plate, and the coupler may be a rivet.

BEST MODE Hereinafter, preferred embodiments for realizing the present invention will be described in detail with reference to the accompanying drawings.

For reference, in describing the present invention, the same reference numerals will be used for the clarity of description for the configuration of the present invention which is the same as the drawings cited in the prior art.

1 is a cross-sectional view showing the configuration of a cap assembly of a secondary battery according to the present invention. As shown in detail in FIG. 1, the secondary battery of the present invention is insulated through a can 4 in which a positive electrode, a negative electrode, and a separator are wound together and received, and a gasket 6 inserted into an opening of the can 4. It is composed of a cap assembly 80 coupled in a state.

The cap assembly 80 is stacked in the order of the cap cover 10, the current limiter 12, the safety plate 100, the insulator 120, and the current blocking disk 140.

In the cap assembly 80 configured as described above, the current blocking disk 140 is coupled by the variable part 100A of the safety plate 100 and the coupler 160.

The coupler 160 is also preferably a rivet.

2 is an exploded perspective view of the safety plate 100 and the current blocking disk 140. As shown in FIG. 2, holes 100B and 140A are formed in the variable part 100A and the current blocking disk 140 of the safety plate 100 to connect the coupler 160, and the variable part 100A. The hole 100B of the shape of the hole (100B) in the Y- shape so that the variable portion (100A) of the safety plate 100 is easily raised and short-circuited from the current blocking disk 140 when the internal pressure rises, In addition, the current blocking disk 140 includes a plurality of vent holes 140B so that the pressure inside the battery acts directly on the safety plate 100.

In the cap assembly 80 configured as described above, when the internal pressure of the battery rises above the prescribed pressure, the variable portion 100A of the safety plate 100 is raised to block the current by being shorted from the current blocking disk 140. do.

The safety device of the present invention can determine the operating pressure large or small by the notch 100C formed on both bottom surfaces of the safety plate 100 and the Y-shaped hole 100B formed in the variable portion.

3A, 3B, and 3C are operation state diagrams of a safety device of a secondary battery according to an embodiment of the present invention. When the pressure inside the battery rises, as shown in FIG. 3A, the variable portion 100A of the safety plate 100 starts to rise, and as shown in 3B, the variable portion 100A according to the increase in the internal pressure. ) Cuts off the current by short-circuiting from the current blocking disk 140, and the notch 100C of the safety plate 100 is broken as shown in FIG. 3C to release the gas inside the battery.

According to such a configuration, the safety device of the present invention can operate accurately at the operating pressure specified by combining the safety plate 100 and the current blocking disk 140 with the coupler 160, and the external shock due to the drop of the battery, etc. Reliability can also be achieved.

As described above, the safety device of the secondary battery according to the present invention substantially solves the problems of the prior art.

The safety device of the secondary battery of the present invention combines the variable portion of the safety plate and the current blocking disk as a coupler, the variable portion is raised by the increased pressure therein, and the short circuit from the current blocking disk to cut off the current and the operating pressure of the safety device. You can set the timing correctly. In addition, reliability can also be improved against external shocks such as drops.

Therefore, the secondary battery according to the present invention can be operated correctly when the internal pressure of the battery rises above the prescribed pressure, thereby ultimately ensuring safety against abnormal operation and explosion of the battery.

The present invention is not limited to the above-described embodiment, and it is apparent that many modifications are possible by those skilled in the art within the technical spirit of the present invention.

Claims (3)

In the safety device of a secondary battery formed by laminating a current blocking disk, an insulation, and a safety plate in the upper opening of the can, A current blocking disk having a plurality of vent holes, a safety plate having a variable portion connected to the current blocking disk, and a coupler fastened through the current blocking disk and the variable portion, wherein the variable portion is increased by internal pressure when the internal pressure increases. A secondary battery safety device, characterized in that for expanding and shorting the current blocking disk to cut off the current. The safety device of a secondary battery according to claim 1, wherein notches are formed on both bottom surfaces of the safety plate. The safety device of claim 1, wherein the coupler may be a rivet.