KR100420149B1 - Secondray battery applying safety device - Google Patents

Abstract

Disclosed is a secondary battery employing a safety device. The present invention provides a plurality of battery parts stacked in the order of a positive electrode plate, a separator, a negative electrode plate; and a case in which the battery unit is accommodated, and a case in which an electrolyte is injected; A rupture portion installed in the case to form a discharge hole in the case to deflate and discharge gas to the outside, wherein the rupture portion is installed inside the case in a direction that contracts when the internal pressure of the battery increases. By forming a discharge hole on the side, it is possible to quickly discharge the gas to the outside through this passage. As a result, the battery can prevent explosion and fire.

Description

Secondary battery employing safety device {Secondray battery applying safety device}

The present invention relates to a secondary battery, and more particularly, to a secondary battery employing a safety device with an improved structure to break the case so that it can be quickly discharged to the outside when gas is generated from the inside of the battery.

Examples of the secondary battery that can be charged and discharged include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-hydrogen batteries, and lithium secondary batteries. Among them, the lithium secondary battery has a working voltage of 3.6V, which is three times better than nickel-cadmium batteries or nickel-metal hydride batteries, which are widely used as power sources for electronic devices, and has excellent energy density per unit weight. have.

Lithium secondary batteries can be classified into liquid electrolyte batteries and polymer electrolyte batteries according to the type of electrolyte. Generally, 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.

The lithium secondary battery may be manufactured in various forms, and typical shapes include cylindrical and rectangular shapes which are mainly used in lithium ion batteries. Lithium polymer batteries, which are in the spotlight in recent years, are made of flexible materials, and their shapes are relatively free. In addition, it is excellent in safety and light weight, which can be said to be advantageous for slimming and lightening portable electronic devices.

Referring to FIG. 1, the lithium polymer battery 10 includes a battery unit 11 and a case 12 accommodating the battery unit 11. As is well known, the battery unit 11 is composed of a separator interposed between the positive electrode plate, the negative electrode plate, the positive electrode and the negative electrode plate, and is laminated in plural numbers in the order of the positive electrode plate, the separator, and the negative electrode plate.

As for the battery part 11, each electrode tab 13 is pulled out along the edge of the some positive electrode and the negative electrode plate, and these are mutually energizable in the state assembled by each pole plate. The electrode tabs 13 are respectively welded to the electrode terminals 14 connectable with external terminals.

The battery 10 is provided with a case 12 in which the above-mentioned battery unit 11 is mounted. The case 12 has a space portion in which the battery unit 11 can be accommodated, and the upper and lower cases are joined to be separated from each other.

In the battery 10 having the above structure, the battery unit 11 is mounted in the case 12 and then the electrolyte is injected. In addition, heat and pressure are applied to the case 12 to seal the battery 10 firmly.

However, when the internal pressure increases due to the generation of gas inside the battery, the battery 10 has a weak mechanical strength to maintain its shape, which is indicated by a dotted line toward the center of the case 12 as indicated by the arrow. As the contraction occurs.

In this shrinkage process, the battery unit 11 may be deformed. As the battery unit 11 is pressed against the contracted case 12, the battery unit 11 and the electrode terminal 14 may locally generate a short circuit.

In addition, when overcharged or exposed at high temperatures, a gas having a high ignition potential such as H ₂ , CO, CO ₂ may be generated in the case 12 due to the reaction between the electrolyte solution and the active material layer or the decomposition reaction of the electrolyte solution and the active material layer itself. As a result, an increase in the internal pressure may cause ignition or explosion of the battery 10. Therefore, when the internal pressure is higher than a certain level due to the generation of gas, a safety device that can quickly discharge the gas to the outside will be required.

The present invention is to solve the above problems, to provide a secondary battery employing a safety device with an improved structure to induce the breakage of the case in the absence of the battery to quickly discharge the gas to the outside. There is this.

1 is a schematic view showing a state in which a conventional secondary battery is deformed,

2 is a perspective view of a rechargeable battery according to a first exemplary embodiment of the present invention;

3 is a schematic diagram illustrating a state in which the secondary battery of FIG. 2 is deformed;

4 is a plan view illustrating a rechargeable battery according to a second exemplary embodiment of the present invention;

5 is a perspective view illustrating a rechargeable battery according to a third exemplary embodiment of the present invention.

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

20 Secondary battery 21 Battery compartment

22 Case 23 Positive plate

24 ... cathode plate 25 ... separator

26 Anode tab 27 Anode tab

28 Anode terminal 29 Anode terminal

200 ... rupture 210

220.bed

In order to achieve the above object, a secondary battery employing a safety device according to an aspect of the present invention,

A plurality of battery units stacked in order of a positive electrode plate, a separator, and a negative electrode plate;

A case in which the battery unit is accommodated and in which an electrolyte is injected; And

It is installed in the case along the direction in which the case shrinks due to the increase in the internal pressure of the battery, forming a discharge hole in the case when the contraction; and a burst portion for discharging the gas to the outside.

The rupture unit may be any one selected from a metal material or a polymer resin that does not react with the electrolyte.

In addition, the rupture portion is a plate member, characterized in that the shape of the needle portion in which both ends are in contact with the inner surface in the direction in which the case is contracted.

Further, the rupture portion is characterized in that the electrode tab drawn out from the electrode plate is fitted to set the position, and both ends are positioned in the width direction of the case.

Further, the rupture portion is located behind the battery unit, characterized in that both ends are located in the width direction of the case.

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

2 shows a lithium polymer battery 20 according to a first embodiment of the present invention.

Referring to the drawings, the battery 20 includes a battery unit 21 and a case 22 in which the battery unit 21 is mounted.

The battery unit 21 includes a positive electrode plate 23 made of a positive electrode current collector and a positive electrode active material layer formed on at least one surface of the positive electrode current collector, and a negative electrode active material layer formed on at least one surface of the negative electrode current collector and the negative electrode current collector. And a separator 25 interposed between the cathode plate 24 and the anode plate 23 and the anode plate 24 to electrically insulate them. A plurality of such battery units 21 are stacked in the order of the positive electrode plate 23, the separator 25, and the negative electrode plate 24.

The positive electrode tab 26 and the negative electrode tab 27 are drawn out from one edges of the positive electrode plate 23 and the negative electrode plate 24, and are connected to each other so that they can be energized with each other. The positive and negative electrode tabs 26 and 27 are welded to the positive electrode terminal 28 and the negative electrode terminal 29 connected to external terminals at their ends.

The battery 20 is provided with a case 22 for mounting the battery unit 21 described above. The case 22 is composed of an upper case 22a and a lower case 22b, and the upper and lower cases 22a and 22b are integrally bonded to at least one edge and the remaining edges are separated. Form. In addition, one of the upper and lower cases 22a and 22b is provided with a space part 200 in which the battery part 21 can be accommodated. The edge surfaces serve as a seal for providing a surface that is heat-sealed to seal the upper and lower cases 22a and 22b after the battery unit 21 is mounted.

According to a feature of the present invention, if the case 22 is deformed due to gas generation inside the battery 20, the case 22 is installed in a direction in which the case 22 is contracted so that the gas is discharged to the outside. The bursting unit 200 which can be discharged quickly is installed.

In more detail as follows.

Inside the case 22, a tearing unit 200 is installed in a forward direction in which the battery unit 21 is installed. The rupture unit 200 is made of any one metal material selected from aluminum, copper, and nickel that do not react with the electrolyte, or any one polymer resin selected from polypropylene (PP) and polyethylene (PE).

The rupture unit 200 is installed in a direction in which the case 22 is contracted, and preferably has a length that can be fit in the width direction of the case 22. The rupture unit 200 is provided with a body portion 210 made of a plate material. The main body portion 210 is installed in front of the case 22 in an upright form in the longitudinal direction.

At both ends of the main body portion 210, a needle-like portion 220 having a pointed shape is formed. The needle part 220 is in contact with the inner side of the long side portion of the case 22. In addition, the main body 210 has a positioning hole 211 is formed so that the positive and negative terminals 28, 29 can be aligned in the case 22 in place. In this case, if the rupture unit 200 is made of a metal material, an insulating material must be formed on the outer surface of the anode and cathode terminals 28 and 29 to prevent short circuit of the electrode plate.

The operation of the secondary battery 20 having the structure as described above is as follows.

The battery 20 generates gas from the inside by reaction between the electrolyte solution and the active material layer or decomposition reaction of the electrolyte solution and the active material layer itself due to overcharging or exposure at a high temperature. Puffed swelling will occur.

When such a swelling phenomenon occurs, as illustrated in FIG. 3, the battery 20 causes the case 22 to contract to the center portion (arrow direction). At this time, the rupture unit 200 is provided inside the case 22. The rupture unit 200 is in contact with the needle portion 220 on the inner side of the long side of the case 22.

For this reason, when the inside of the case 22 is more than the appropriate pressure, the needle portion 220 is formed through the predetermined portion of the side of the case 22 to form a discharge hole. As a result, the gas is discharged through the discharge hole to remove the flammable gas, thereby preventing fire or explosion.

4 illustrates a secondary battery 40 according to a second embodiment of the present invention.

Here, the same reference numerals as in the above-described drawings indicate the same members having the same function.

Referring to the drawings, the battery 40 has a battery unit 21 is mounted inside the case 22. The positive and negative electrode tabs 26 and 27 drawn out from the battery units 21 stacked in the order of the positive plate, the separator and the negative electrode plate are electrically connected to the positive and negative terminals 28 and 29 protruding from the outside.

Here, the rupture unit 400 is provided behind the battery unit 21 in the case 22. That is, the rupture unit 400 is a plate made of a metal material or a polymer resin that does not react with the electrolyte, and is provided in a form of standing upright inside the case 22. Both ends of the rupture portion 400 are in contact with the inner surface of the case 22 in the width direction, respectively, and the shape of the rupture portion 400 forms a pointed needle portion 410.

In the battery 40 having such a structure, when the internal pressure increases due to the generation of ignitable gas from the inside, the case 22 contracts toward the center portion. In this case, since the rupture part 400 is installed in the direction in which the case 22 is contracted, the needle part 410 presses the inner surface of the case 22 to form a discharge hole. Accordingly, the gas can be discharged to the outside through the discharge hole.

5 illustrates a rechargeable battery 50 according to a third embodiment of the present invention.

Referring to the drawings, the battery 50 includes a battery unit 51 and a case 52 in which the battery unit 21 is mounted.

The battery unit 21 includes a positive electrode plate 53, a negative electrode plate 54, and a separator 55 interposed therebetween, and the positive and negative electrodes are formed from one edge of the positive and negative electrode plates 53 and 54. Tabs 56 and 57 are drawn out, and the positive and negative tabs 56 and 57 are welded to the positive and negative terminals 58 and 59 at their ends.

In addition, the battery 50 is provided with a case 52 for mounting the battery unit 51, the case 22 is composed of upper and lower cases 52a and 52b that can be separated up and down.

Here, when the case 52 is deformed due to the overcharging of the battery 50 or the generation of gas due to the high temperature, the bursting unit 500 is installed in the case 52 so that it can be quickly discharged to the outside. have.

The rupture unit 500 is made of a metal material or a polymer resin that does not react with the electrolyte, and is installed in a direction in which the case 52 is contracted. At this time, the rupture unit 500 is installed on the bottom surface of the lower case 52b, and the positive and negative electrode tabs 56 and 57 are positioned on the upper surface thereof.

The rupture portion 500 has a length corresponding to the width direction of the case 52, and the needle-shaped portion 520 of the pointed shape is formed at both ends of the body portion 510 made of a plate material. The needle portion 520 is in contact with the inner side of the long side portion of the case 52.

In the secondary battery 50 having the above structure, when the gas is generated by the reaction between the electrolyte and the electrode plate due to overcharging or exposure at high temperature, the rupture part 500 is installed in the direction in which the case 52 contracts. It forms a discharge hole in the. As a result, the gas is quickly discharged through the discharge hole, thereby preventing the ignition or explosion of the battery 50 in advance.

As described above, the secondary battery employing the safety device of the present invention is provided with a rupture portion in the direction of contraction when the internal pressure of the battery increases in the case, so that the rupture portion forms a discharge hole on the case side, and the gas passes through the passage. It is possible to quickly discharge to the outside. As a result, the battery can prevent explosion and fire.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (8)

A plurality of battery units stacked in order of a positive electrode plate, a separator, and a negative electrode plate; A case in which the battery unit is accommodated and in which an electrolyte is injected; And It is a plate installed in the case, both ends are in contact with the inner surface in the direction in which the case is contracted so that the gas can be discharged to form a discharge hole by drilling a part of the case when the case shrinks due to the increase in the internal pressure of the battery A secondary battery employing a safety device, comprising: a rupture portion formed of a metal material or a polymer resin which forms a needle-shaped portion which does not react with an electrolyte solution. delete The method of claim 1, The metal material is a secondary battery employing a safety device, characterized in that any one selected from copper, nickel, aluminum. The method of claim 1, The secondary battery employing a safety device, wherein the polymer resin is any one selected from polypropylene and polyethylene. delete The method of claim 1, The breakable part is a secondary battery employing a safety device, characterized in that the electrode tab drawn out from the electrode plate is fitted to set its position, and both ends are positioned in the width direction of the case. The method of claim 1, The rupture unit is a secondary battery employing a safety device, characterized in that located at the rear of the battery unit, both ends are located in the width direction of the case. The method of claim 1, The rupture portion is a secondary battery employing a safety device, characterized in that located on the inner surface of the case corresponding to the lower side of the electrode tab drawn out from the electrode plate, both ends are located in the width direction of the case.