KR102522705B1 - Secondary Battery - Google Patents

Abstract

The present invention relates to a secondary battery, comprising: an electrode assembly; and a case accommodating the electrode assembly, wherein the case has a double structure including a first pouch accommodating the electrode assembly and a second pouch accommodating the first pouch.

Description

Secondary Battery {Secondary Battery}

[0001] The present invention relates to a secondary battery, and more particularly, to a secondary battery with high safety through a double pouch structure.

In general, a secondary battery refers to a battery that can be charged and discharged, unlike a primary battery that cannot be charged, and such a secondary battery is widely used in the field of high-tech electronic devices such as phones, notebook computers and camcorders.

The secondary battery described above is classified into a can-type secondary battery in which the electrode assembly is embedded in a metal can and a pouch-type secondary battery in which the electrode assembly is embedded in a pouch. The pouch-type secondary battery includes an electrode assembly, an electrolyte solution, the electrode assembly and the electrolyte solution. Includes a pouch for accommodating. The pouch includes an accommodating portion accommodating the electrode assembly and the electrolyte, and a sealing portion sealing the accommodating portion.

However, in the secondary battery described above, the pouch expands with gas generated by a mutual reaction between the electrode assembly and the electrolyte during charge and discharge. Electrolyte is ejected to the outside, and as a result, there is a problem in that explosion or ignition occurs.

Patent Registration No. 10-0958649

The present invention was invented to solve the above problems, and an object of the present invention is to form a pouch for accommodating an electrode assembly and an electrolyte in a double structure, thereby greatly securing safety against overheating and overcharging, As a result, it is to provide a secondary battery capable of preventing explosion or ignition.

A secondary battery according to an embodiment of the present invention for achieving the above object includes an electrode assembly; and a case accommodating the electrode assembly, wherein the case may have a double structure including a first pouch accommodating the electrode assembly and a second pouch accommodating the first pouch.

A vacuum state may be formed in a space between the first pouch and the second pouch.

A secondary battery comprising a safety member for suppressing a temperature increase inside the second pouch in which the first pouch is accommodated.

The safety member may be composed of a plurality of capsules containing an extinguishing material.

The second pouch may be formed of a resin layer having heat resistance.

The second pouch may be formed of a transparent or translucent resin layer to identify the first pouch.

The first pouch includes a first accommodating portion accommodating the electrode assembly and a first sealing portion sealing the first accommodating portion, and the second pouch includes a second pouch accommodating the entirety of the first pouch. It may include an accommodating part and a second sealing part sealing the second accommodating part.

Electrode leads that are drawn out through the first and second sealing parts may be coupled to the electrode assembly.

An adhesive film for increasing sealing force may be provided between the electrode lead and the second sealing part.

The second sealing part may have a smaller width than the first sealing part.

The first pouch and the second pouch may be formed of the same material.

The first pouch and the second pouch may be formed of different materials.

Through the above embodiment, the present invention has the following effects.

First: In the secondary battery of the present invention, the case is characterized by having a double structure including first and second pouches. Due to this feature, when the first pouch is ruptured, external exposure of the electrode assembly and electrolyte through the second pouch can be prevented, and thus safety against overheating and overcharging can be greatly increased, and as a result, explosion or ignition can be prevented. It can be prevented.

Second: In the secondary battery of the present invention, a vacuum state is formed in the space between the first pouch and the second pouch.

Third: In the secondary battery of the present invention, a safety member for suppressing temperature rise is included inside the second pouch in which the first pouch is accommodated. Due to this feature, it is possible to prevent secondary rupture by cooling the high-temperature electrolyte solution released when the first pouch ruptures, and as a result, stability can be greatly improved.

Fourth: In the secondary battery of the present invention, the safety member is characterized by being composed of a capsule containing an extinguishing material. Due to this feature, it is possible to prevent the first and second pouches from being damaged by the extinguishing material in normal times, and to lower the temperature of the electrolyte solution by the extinguishing material to the outside while the capsule is melted by the high-temperature electrolyte solution when the first pouch is ruptured. there is.

Fifth: In the secondary battery of the present invention, the first pouch and the second pouch are, for example, formed of the same material. Due to these characteristics, the safety of the secondary battery against rupture and explosion can be doubled.

Sixth: In the secondary battery of the present invention, as another example, the first pouch and the second pouch are formed of different materials.

Seventh: In the secondary battery of the present invention, the electrode assembly is coupled with electrode leads exposed to the outside through the first and second pouches, and includes an adhesive film between the electrode leads and the sealing portion of the second pouch. have Due to this feature, it is possible to increase the sealing force between the electrode lead and the sealing part of the second pouch, and as a result, leakage of high-temperature electrolyte solution to the outside between the electrode lead and the sealing part of the second pouch can be prevented. there is.

Eighth: In the secondary battery of the present invention, the sealing portion of the second pouch has a smaller width than the sealing portion of the second pouch. Due to this characteristic, it is possible to prevent the size of the secondary battery from being excessively enlarged, and it is possible to design a more compact size.

1 is a perspective view showing a secondary battery according to a first embodiment of the present invention;
2 is a cross-sectional view of a secondary battery according to a first embodiment of the present invention.
3 is a cross-sectional view showing a ruptured state of a first pouch in a secondary battery according to a first embodiment of the present invention;
4 is a cross-sectional view showing a secondary battery according to a second embodiment of the present invention.
5 is a cross-sectional view of a secondary battery according to a third embodiment of the present invention.
6 is a graph showing experimental results of the secondary battery according to the first embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

[Secondary battery according to the first embodiment]

As shown in FIG. 1, the secondary battery 100 according to the first embodiment of the present invention includes an electrode assembly 110, an electrolyte solution 120, and a device for accommodating the electrode assembly 110 and the electrolyte solution 120. Case 130 is included.

The electrode assembly 110 has a structure in which a plurality of electrodes and a plurality of separators are alternately stacked. For example, the electrode assembly 110 includes one or more radical units, and the radical units have a structure in which a first electrode and a second electrode are alternately stacked with a separator interposed therebetween. The first electrode may be an anode and the second electrode may be a cathode.

Also, in the electrode assembly 110, electrode tabs are provided on a plurality of electrodes, and electrode leads 140 are coupled to the electrode tabs.

The case 130 is for accommodating the electrode assembly 110 and has a multi-accommodating structure in which a plurality of pouches are accommodated in order of size from small to large. For example, the case 130 has a double structure including a first pouch 131 accommodating the electrode assembly 110 and a second pouch 132 accommodating the first pouch 131. have

The first pouch 131 includes a first accommodating part 131a accommodating the electrode assembly 110 and a first sealing part 131b sealing the first accommodating part 131a.

The second pouch 132 includes a second accommodating portion 132a accommodating the first pouch 131 in which the electrode assembly 110 is accommodated, and a second sealing portion sealing the second accommodating portion 132a ( 132b).

Here, the inner space of the second accommodating part 132a is formed larger than the volume of the first pouch 131 so as to stably accommodate the first pouch 131 .

In addition, a buffer pad may be provided on an inner surface of the second accommodating part 132a to mitigate an impact force when the first pouch 131 collides.

Meanwhile, a vacuum state is formed in the space between the first pouch 131 and the second pouch 132 in the case 130 .

Meanwhile, in the case 130, the first pouch 131 and the second pouch 132 are formed of a laminate of the same material as shown in FIG. For example, the first pouch 131 has a structure in which a resin layer 131c, a metal layer 131d, and a resin layer 131e are sequentially stacked, and the second pouch 132 is the first pouch ( 131), the resin layer 132c, the metal layer 132d, and the resin layer 132e are sequentially stacked.

In this way, the first pouch 131 and the second pouch 132 are formed of a laminated structure of the same material, so that even if the first pouch 131 is ruptured, it can be stably protected through the second pouch 132, As a result, the safety of the secondary battery against rupture and explosion can be doubled.

Meanwhile, referring to FIG. 1 , in the case 130, the width α of the second sealing portion 132b has a smaller width than the width β of the first sealing portion 131b. That is, when the width of the second sealing portion 132b is large, the size of the secondary battery 100 is excessively enlarged. Here, the first sealing part 131b should have a large width to maintain a stable sealing force even if the first pouch expands due to overfilling, but the second sealing part 132b is released from the first pouch 131. Since only the leakage of the electrolyte solution 120 needs to be prevented, it is not necessary to have a width equal to or greater than that of the first sealing portion 131b.

As such, the second sealing portion 132b has a smaller width than the first sealing portion 131b, so that the size of the secondary battery can be prevented from being excessively enlarged, and a more compact size can be designed.

Here, the width of the second sealing part 132b is not limited to being smaller than the width of the first sealing part 131b, and the width of the second sealing part 132b depends on the mechanical device to which the secondary battery is applied. It may be equal to or larger than the width of (131b).

Meanwhile, the tip of the electrode lead 140 coupled to the electrode assembly 110 is drawn out through the first and second sealing parts 131b and 132b of the first and second pouches 131 and 132, and , Accordingly, the electrode lead 140 can be double-sealed, and as a result, the sealing force can be greatly increased.

In particular, an adhesive film 150 for increasing sealing force is provided between the electrode lead 140 and the second sealing part 132b, and the adhesive film 150 is released when the first pouch 131 is ruptured. The sealing force between the electrode lead 140 and the second sealing part 132b is prevented from being weakened by the high-temperature electrolyte 120, and as a result, external exposure of the electrolyte 120 can be largely prevented.

Hereinafter, the operating state of the secondary battery 100 according to the first embodiment of the present invention having the above configuration will be described.

As shown in FIG. 3, the secondary battery 100 according to the first embodiment of the present invention generates high heat and gas due to a mutual reaction between the electrode assembly 110 and the electrolyte 120 when overcharging or short circuit occurs, The first pouch 131 of the case 130 is inflated by the high heat and gas. At this time, when the first pouch 131 is excessively inflated, the weak part (“A” part shown in FIG. 3) is ruptured, The high-temperature electrolyte solution 120 accommodated in the first pouch 131 is discharged to the outside, and the high-temperature electrolyte solution 120 discharged from the first pouch 131 is received inside the second pouch 132 and leaks to the outside. can prevent

Therefore, the secondary battery 100 according to an embodiment of the present invention includes the case 130 having a double structure, so that the electrolyte 120 can be prevented from being exposed to the outside even when overcharging or short circuiting occurs, and as a result, overheating and overcharging safety can be greatly increased.

Hereinafter, in describing other embodiments of the present invention, the same configuration numerals are used for configurations having the same configurations and functions as those of the above-described embodiment, and redundant descriptions are omitted.

[Secondary battery according to the second embodiment]

As shown in FIG. 4 , the secondary battery case 130 according to the second embodiment includes a first pouch 131 and a second pouch 132 accommodating the first pouch 131 . .

Here, a safety member 133 for suppressing temperature rise is included inside the second pouch 132 in which the first pouch 131 is accommodated, and the safety member 133 is made of a liquid material having a cooling component. and is filled in all or part of the space between the first pouch 131 and the second pouch 132.

Therefore, when the high-temperature electrolyte 120 is discharged into the second pouch 132 due to the rupture of the first pouch 131, the case 130 is mixed with the high-temperature electrolyte 120 and the safety member 133. The amount of heat of the electrolyte solution 120 can be greatly reduced, and accordingly, the second pouch 132 can be prevented from bursting, and as a result, stability can be improved.

Meanwhile, the safety member 133 is composed of a plurality of capsules containing an extinguishing material. That is, the first and second pouches 131 and 132 are prevented from being damaged while the extinguishing material is normally embedded in the capsule, and when the pouch 131 is ruptured, the high-temperature electrolyte 120 protects the second pouch 132 ) It is possible to lower the amount of heat of the electrolyte 120 by the extinguishing material released to the outside while the built-in capsule is high.

[Secondary battery according to the third embodiment]

As shown in FIG. 5 , the secondary battery case 130 according to the third embodiment includes a first pouch 131 and a second pouch 132' accommodating the first pouch 131. do.

Referring to FIG. 5, the first pouch 131 and the second pouch 132' are made of different materials. For example, the first pouch 131 has a structure in which a resin layer 131c, a metal layer 131d, and a resin layer 131e are sequentially stacked, and the second pouch 132' has a resin layer 132c. ') is formed. That is, the first pouch 131 is formed of a three-layer laminate to protect the electrode assembly 110 and the electrolyte, and the second pouch 132' provides high-temperature energy released when the first pouch 131 is ruptured. It is formed as a single layer of resin because only the withdrawal of the electrolyte solution needs to be prevented.

In this way, the first pouch 131 and the second pouch 132' are formed in different laminated structures, thereby securing safety against rupture of the first pouch and reducing manufacturing costs.

Here, the resin layer 132c', which is the second pouch 132', is formed of a material having heat resistance, and thus prevents the second pouch 132' from being ruptured while being melted by the high-temperature electrolyte solution 120. can

Meanwhile, the thickness of the resin layer 132c' of the second pouch 132' is greater than that of the resin layer 131c included in the first pouch 131. That is, the first pouch 131 includes the metal layer 131b, but the resin layer 132c' of the second pouch 132' does not include the metal layer, so that the high-temperature electrolyte 120 can be stored more stably. To accommodate it, the thickness of the resin layer 131c included in the first pouch 131 may be greater than that of the resin layer 131c.

[Experiment preparation]

Ignition point when the secondary battery 100 according to the first embodiment of the present invention having a double pouch structure (hereinafter referred to as an example) and a secondary battery having a single pouch structure (hereinafter referred to as a comparative example) are overcharged and temperature changes were measured.

Here, the first pouch provided on the inside of the double pouch of the embodiment and the pouch of the comparative example have the same structure and material.

And, as shown in Figure 6, the experimental results of the Examples and Comparative Examples were summarized in a graph.

[Experiment result]

Referring to FIG. 6, the first pouch 131 ruptures first at the point of overcharge of 131%, the voltage and temperature drop rapidly, and the second pouch 132 ruptures secondarily at the point of 142% overcharge. As a result, ignition occurred.

That is, in the embodiment, ignition occurred as all of the double-structured pouches ruptured at the point of overcharging by 142%, and at this time, the ignition temperature was measured at 139° to 141°.

Referring to FIG. 6 for Comparative Example, the pouch ruptured at the point of overcharge of 130%, the temperature and voltage dropped rapidly, and ignition occurred at the point of overcharge of 138%. At this time, the ignition temperature was measured at 79 ° ~ 81 °.

Therefore, as a result of the experiment as described above, it can be confirmed that the embodiment has the effect of delaying the ignition point due to overcharge compared to the comparative example, and it can be confirmed that the ignition occurs at a higher temperature than the comparative example.

The scope of the present invention is indicated by the claims to be described later rather than the above detailed description, and various embodiments derived from the meaning and scope of the claims and equivalent concepts thereof are possible.

100: secondary battery
110: electrode assembly
120: electrolyte
130: case
131: first pouch
132: second pouch
133: safety member

Claims (11)

electrode assembly; and
Including a case accommodating the electrode assembly,
The case has a double structure including a first pouch accommodating the electrode assembly and a second pouch accommodating the first pouch in a form surrounding the entire first pouch,
The second pouch is formed of a resin layer having heat resistance,
The second pouch is formed of a transparent or translucent resin layer to identify the first pouch,
The thickness of the resin layer of the second pouch is formed greater than the thickness of the resin layer included in the first pouch,
The second pouch includes a second accommodating portion accommodating the entire first pouch and a second sealing portion sealing the second accommodating portion, and the inner surface of the second accommodating portion collides with the first pouch. A secondary battery provided with a buffer pad for mitigating an impact force at the time of application. The method of claim 1,
A secondary battery in which a vacuum state is formed in a space between the first pouch and the second pouch. The method of claim 1,
A secondary battery comprising a safety member for suppressing a temperature rise inside the second pouch in which the first pouch is accommodated. The method of claim 3,
The safety member is a secondary battery composed of a plurality of capsules containing an extinguishing material. delete delete The method of claim 1,
The first pouch includes a first accommodating portion accommodating the electrode assembly, and a first sealing portion sealing the first accommodating portion. The method of claim 7,
A secondary battery coupled to the electrode assembly is coupled to an electrode lead that is drawn out through the first and second sealing parts. The method of claim 8,
A secondary battery comprising an adhesive film for increasing sealing force between the electrode lead and the second sealing part. The method of claim 1,
The secondary battery wherein the first pouch and the second pouch are formed of the same material. The method of claim 1,
The secondary battery wherein the first pouch and the second pouch are formed of different materials.

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