JP7197222B2 - secondary battery - Google Patents

Description

[Cross reference to related applications]
This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0118867 dated October 5, 2018 and Korean Patent Application No. 10-2019-0122402 dated October 2, 2019, and the Korean Patent All content disclosed in the application documents is incorporated as part of this specification.

The present invention relates to secondary batteries.

A secondary battery can be recharged unlike a primary battery, and has been extensively researched and developed in recent years due to the possibility of miniaturization and large capacity. Demand for secondary batteries as an energy source is rapidly increasing with the development of technology and increase in demand for mobile devices.

Secondary batteries are classified into coin-shaped cells, cylindrical cells, prismatic cells, and pouch-shaped cells according to the shape of the battery case. An electrode assembly mounted inside a battery case of a secondary battery is a chargeable/dischargeable power generation element having a laminated structure of electrodes and separators.

The electrode assembly is a jelly-roll type in which a separation membrane is interposed between a sheet-type positive electrode and a negative electrode coated with an active material, and a separation membrane is interposed between a plurality of positive electrodes and negative electrodes. It can be roughly classified into a stack type in which a state is sequentially laminated, and a stack/folding type in which a stack type unit cell is wound with a long separating film. Among them, the jelly roll type electrode assembly is widely used because it is easy to manufacture and has high energy density per unit weight.

Korean Patent Publication No. 10-2016-0010121

One aspect of the present invention is to provide a secondary battery that can improve battery stability by inducing a short circuit when high heat and high pressure occur.

A secondary battery according to an embodiment of the present invention includes an electrode assembly in which a first electrode, a separation membrane, and a second electrode are alternately laminated and wound up, and an accommodating portion for accommodating the electrode assembly therein. a can including a first can and a second can which are formed in a cylindrical shape with openings facing each other; and an insulation for insulating an overlapping portion between the first and second cans a body, wherein the first can is electrically connected to the first electrode, the second can is electrically connected to the second electrode, and the insulator is formed with a through hole or a cut line. A short-circuit induction through portion is formed between the first can and the second can via the short-circuit induction through portion whose shape is deformed when the insulator receives heat or pressure and contracts or expands. can be shorted.

According to the present invention, an insulator having a short-circuit induction penetration for electrically connecting the first electrode and the second electrode to the first can and the second can and insulating the first can and the second can and the insulator is deformed by contraction or expansion under high heat or high pressure, and a short circuit can be caused between the first can and the second can via the short circuit induction penetration. This can lower the energy level of the battery and prevent the battery from exploding.

1 is a perspective view showing a secondary battery according to an embodiment of the present invention; FIG. 1 is a cross-sectional view showing a secondary battery according to an embodiment of the present invention; FIG. 1 is an exploded perspective view showing a secondary battery according to an embodiment of the present invention; FIG. 1 is a front view showing a secondary battery according to an embodiment of the present invention; FIG. 1 is a perspective view showing a first example of an insulator in a secondary battery according to an embodiment of the present invention; FIG. FIG. 4 is a perspective view showing a second example of an insulator in a secondary battery according to an embodiment of the present invention; FIG. 4 is a perspective view showing a third example of an insulator in a secondary battery according to an embodiment of the present invention; FIG. 4 is a perspective view showing a fourth example of an insulator in a secondary battery according to an embodiment of the present invention; 4A and 4B are perspective views showing states before and after deformation of an insulator in a secondary battery according to an embodiment of the present invention; FIG. 4 is a perspective view showing a secondary battery according to another embodiment of the present invention; FIG. 4 is an exploded perspective view showing a secondary battery according to another embodiment of the present invention; FIG. 4 is a perspective view showing a secondary battery according to still another embodiment of the present invention; FIG. 4 is an exploded perspective view showing a secondary battery according to still another embodiment of the present invention; FIG. 4 is a diagram showing displacements received by a can in the secondary battery according to Manufacturing Example 1; FIG. 10 is a view showing the displacement received by the can of the secondary battery according to Manufacturing Example 2; 5 is a diagram illustrating displacement of a can of a secondary battery according to Comparative Example 1; FIG. FIG. 10 is a diagram illustrating displacement of a can of a secondary battery according to Comparative Example 2;

Objects, particular advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments in conjunction with the drawings. In the addition of reference numbers to components in each figure in this specification, as much as possible, identical components have the same numbers, even if they appear on other figures. It should be noted that Also, the present invention may be embodied in many different forms and is not limited to the embodiments set forth herein. In addition, in the description of the present invention, detailed descriptions of related known technologies that unnecessarily obscure the subject matter of the present invention will be omitted.

FIG. 1 is a perspective view showing a secondary battery according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a secondary battery according to an embodiment of the present invention.

Referring to FIGS. 1 and 2, a secondary battery 100 according to an embodiment of the present invention is an electrode assembly in which a first electrode 111, a separation membrane 114, and a second electrode 112 are alternately laminated and rolled up. 110 and a can 120 including a first can 121 and a second can 122 containing the electrode assembly 110 therein;

FIG. 3 is an exploded perspective view showing a secondary battery according to one embodiment of the present invention.

Hereinafter, a secondary battery according to an embodiment of the present invention will be described in more detail with reference to FIGS. 1 to 9. FIG.

Referring to FIGS. 2 and 3, the electrode assembly 110 is a chargeable/dischargeable power generation device, and has a structure in which electrodes 113 and separators 114 are assembled and alternately stacked. Here, the electrode assembly 110 may have a rolled configuration.

Electrodes 113 may include a first electrode 111 and a second electrode 112 . The isolation film 114 separates and electrically insulates the first electrode 111 and the second electrode 112 . Here, the first electrode 111 and the second electrode 112 may be formed in a sheet shape and rolled up together with the separation membrane 114 to form a jelly roll. At this time, the electrode assembly 110 may be wound into a cylindrical shape, for example.

The first electrode 111 may include a first electrode current collector 111a and a first electrode active material 111b coated on the first electrode current collector 111a. Also, the first electrode 111 may include a first electrode uncoated portion 111c that is not coated with the first electrode active material 111b.

Here, the first electrode 111 is, for example, a negative electrode, includes a negative current collector (not shown) and a negative active material (not shown) applied to the negative current collector, and is coated with the negative active material. An uncoated negative electrode uncoated portion may be formed.

The negative electrode current collector may be, for example, a foil made of copper (Cu) or nickel (Ni). The negative electrode active material may consist of, for example, artificial graphite, lithium metal, lithium alloys, carbon, petroleum coke, activated carbon, graphite, silicon compounds, tin compounds, titanium compounds, or alloys thereof. At this time, the negative electrode active material may further include , for example, non-graphite-based SiO (silica) or SiC (silicon carbide).

The second electrode 112 may include a second electrode current collector 112a and a second electrode active material 112b applied to the second electrode current collector 112a. The second electrode 112 may include a second electrode uncoated portion 112c that is not coated with the second electrode active material 112b.

Here, the second electrode 112 is composed of, for example, a positive electrode, includes a positive current collector (not shown) and a positive active material (not shown) applied to the positive current collector, and is coated with the positive active material. A positive uncoated portion may be formed.

The positive current collector may be, for example, aluminum foil, and the positive active material may be, for example, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron phosphate, or any of these. It may consist of compounds and mixtures containing one or more of

The isolation layer 114 is made of an insulating material and alternately stacked with the first electrode 111 and the second electrode 112 . Here, the separation layer 114 may be positioned between the first electrode 111 and the second electrode 112 and on outer surfaces of the first electrode 111 and the second electrode 112 . At this time, the separation membrane 114 may be positioned on the outermost side in the width direction when the electrode assembly 110 is wound.

Also, the separation membrane 114 may be made of a soft material. At this time, the separation membrane 114 may be formed of, for example, a polyolefin-based resin membrane such as polyethylene or polypropylene having microporosity.

FIG. 4 is a front view showing a secondary battery according to an embodiment of the present invention, and FIG. 5 is a perspective view showing a first example of an insulator in the secondary battery according to an embodiment of the present invention. .

Referring to FIGS. 2 to 4, the can 120 includes a first can 121 and a second can 121 formed in a cylindrical shape with openings facing each other and having a receiving portion for receiving the electrode assembly 110 therein. Two cans 122 may be included.

Here, the first can 121 may be electrically connected to the first electrode 111 and the second can 122 may be electrically connected to the second electrode 112 .

Also, the first can 121 and the second can 122 are formed in a cylindrical shape, the inner peripheral surface of the first can 121 is formed larger than the outer peripheral surface of the second can 122, and the second can 122 is formed on the first can 121. may be inserted.

Further, the first can 121 has a first opening (not shown) that opens in one side direction C1 on one side 121b, and a first connection that is closed in the other side direction C2 on the other side 121c. A portion 121a may be formed. The second can 122 has a second opening 122d opened in the other side direction C2 on the other side 122c, and a second connecting part 122a closed in the one side direction C1 on the side 122b. good. At this time, the end of the first electrode 111 may be connected to the first connecting portion 121a, and the end of the second electrode 112 may be connected to the second connecting portion 122a.

Here, the one side end 123b of the insulator 123 may be extended to be positioned closer to the second connection part 122a than the one side end of the first can 121 . The other side end 123c of the insulator 123 may be extended to be positioned closer to the first connecting part 121a than the other side end of the second can 122 . However, as will be discussed below, if the insulator is coated on the outer peripheral surface of the second can 123, the other end 123c of the insulator 123 may The side edges may be formed to match each other.

At this time, in order to prevent a short circuit, the distance a from the one side end of the first can 121 to the one side end 123b of the insulator 123 is greater than 0, and the second can 122 is insulated from the other side end of the second can 122. The distance b to the other side end 123c of body 123 may be greater than zero.

The insulator 123 may include an insulating material to insulate the overlapping portion between the first can 121 and the second can 122 .

In addition, referring to FIGS. 2 and 5, the insulator 123 may be formed with a short circuit induction through portion 123a-1 formed in the shape of a through hole or a cut line. Here, the first can 121 and the second can 122 can be short-circuited through the short-circuit induction through portion 123a-1, which is deformed by contraction or expansion of the insulator 123 under high heat or high pressure. . Accordingly, the energy level of the secondary battery 100 can be lowered to prevent the secondary battery 100 from exploding. This is due to the fact that the insulator 123 shrinks or expands when subjected to a certain temperature and pressure. When the temperature of the can rises or the can expands under abnormal circumstances, the insulation will also be subjected to high temperature and high pressure, which can cause the insulation to contract or expand and deform in shape.

The insulator 123 may include a polymer material. The polymer material may be, for example, any one of PE (polyethylene), PP (polypropylene), and PET (polyethylene terephthalate). Here, the polymer material may be specifically made of PE (polyethylene) or PP (polypropylene) material having a melting point of 180° C. or less. At this time, more specifically, the polymer material may be, for example, a low-medium density PE having a melting point of 110.degree. A battery explodes at a temperature of about 180 to 200 degrees, and if the insulator made of the above material is used, the first can 121 and the second can 122 are short-circuited before the battery explodes. So the energy level can be low.

On the other hand, since the resistance (R) is a value obtained by multiplying the specific resistance by the area per thickness, the resistance (R) of the cylindrical insulator 123 is
R = Material (p) * Thickness (t) / A = Material (p) * Thickness (t) / (Diameter (d ) * Height (L))
can be written as

A large resistance has the advantage of rapidly reducing the amount of heat generated. However, if the resistance is too large, the heat generation itself can be very small, so the resistance can be adjusted to have a heat generation within a suitable range. At this time, the resistance of the insulator 123 can be adjusted by changing the material (p) and the shape (d, L, t).

Meanwhile, the insulator 123 may be coated on the outer peripheral surface of the second can 122 to form a coating layer, for example. At this time, the insulator 123 may be formed by coating an outer peripheral surface of the second can 122 with an insulating material.

Further, the insulator 123 may be attached to the outer peripheral surface of the second can 122 by any one of painting, printing, cladding, lamination, spraying, masking, dipping, and bonding, as another example. More specifically, painting for applying an insulating material to the outer circumference of the second can 122 , printing for printing the insulating material for the outer circumference of the second can 122 , and insulating material for the outer circumference of the second can 122 . , masking in which a masking agent or insulating material is attached to the outer peripheral surface of the second can 122, and the outer peripheral surface of the second can 122 is immersed in an insulating liquid to insulate Dipping for forming a film, bonding for attaching an insulator to the outer circumference of the second can 122 via an adhesive component, and lamination for laminating the insulator 123 on the outer circumference of the second can 122 ( An insulator 123 may be formed on the outer peripheral surface of the second can 122 through lamination.

Meanwhile, for example, the outer first can 121 may be made of steel, and the inner second can 122 may be made of aluminum. Here, since the material of the second can 122 contains aluminum, the second can 122 often expands due to high heat. Since this happens frequently, a short circuit between the first can 121 and the second can 122 can often occur due to high heat through the short circuit induction through portion 123 a - 1 formed in the insulator 123 .

At this time, the first electrode 111 may be a negative electrode, and the second electrode 112 may be a positive electrode.

FIG. 6 is a perspective view showing a second example of an insulator in a secondary battery according to an embodiment of the present invention, and FIG. 7 is a third example of an insulator in a secondary battery according to an embodiment of the present invention. and FIG. 8 is a perspective view showing a fourth example of the insulator in the secondary battery according to the embodiment of the present invention.

Meanwhile, referring to FIG. 5, as a first example, the insulator 123-1 may have a plurality of short-circuit induction through portions 123a-1 forming at least one or more rows. At this time, specifically, for example, the short-circuit induction through-holes 123a-1 may be formed in the form of through-holes, forming rows along the longitudinal direction of the insulator 123-1.

Also, referring to FIG. 6, as a second example, the insulator 123-2 may have a plurality of short circuit induction through portions 123a-2, forming at least one row. At this time, specifically, for example, the short-circuit induction through portions 123a-2 may be formed in the form of through holes and form rows along the longitudinal direction of the insulator.

Further, referring to FIG. 7, as a third example, the insulator 123-3 may have a plurality of short-circuit induction through portions 123a-3 formed in a lattice shape. At this time, specifically, for example, the short circuit induction through portion 123a-3 may be formed in the form of a through hole.

Further, referring to FIG. 8, as a fourth example, the insulator 123-4 may have a plurality of short circuit induction through portions 123a-4 formed in a cut line shape.

The short-circuit induction through-hole has a size such that the first can and the second can cannot contact each other when the battery is in a normal state, but its shape is deformed when the battery is in an abnormal state. The first can and the second can can be brought into contact with each other.

FIG. 9 is a perspective view showing states before and after deformation of an insulator in a secondary battery according to an embodiment of the present invention. Here, FIG. 9(a) shows the state before deformation of the insulator, and FIG. 9(b) shows the state after deformation.

Referring to FIG. 9, it can be seen that a deformation amount of 0.10647 mm was generated when an internal pressure was generated in the lattice-shaped insulator with a plurality of short-circuit induction through portions formed in the form of through holes.

As a result, it can be seen that the shape of the insulator is deformed by contraction or expansion due to high heat or high pressure, and a short circuit can occur between the first and second cans through the short-circuit induction penetration.

Hereinafter, secondary batteries according to other embodiments of the present invention will be described.

FIG. 10 is a perspective view showing a secondary battery according to another embodiment of the present invention, and FIG. 11 is an exploded perspective view showing a secondary battery according to another embodiment of the present invention.

Referring to FIGS. 10 and 11, a secondary battery 200 according to another embodiment of the present invention includes an electrode assembly in which a first electrode 211, a separator 214, and a second electrode 212 are alternately stacked and wound. It includes a can 220 that includes a first can 221 and a second can 222 that house the three-dimensional body 210 and the electrode assembly 210 therein, and an insulator 223 that insulates the overlapping portion between the first can 221 and the second can 222 . .

In the secondary battery 200 according to another embodiment of the present invention, the materials of the first can 221 and the second can 222 and the first electrode 211 and the second electrode 211 connected therewith are compared with the secondary battery according to the above-described embodiment. There is a difference in polarity between the two electrodes 212 . Therefore, this embodiment will briefly describe the content that overlaps with the first embodiment, and will focus on the points of difference.

More specifically, in the secondary battery 200 according to another embodiment of the present invention, the can 220 is formed in a cylindrical shape having openings facing each other and having a receiving portion for receiving the electrode assembly 210 therein. A first can 221 and a second can 222 may be included.

Here, the first can 221 may be electrically connected to the first electrode 211 and the second can 222 may be electrically connected to the second electrode 212 .

Also, the first can 221 and the second can 222 are formed in a cylindrical shape, the inner peripheral surface of the first can 221 is formed larger than the outer peripheral surface of the second can 222, and the second can 222 is formed on the first can 221. may be inserted.

Further, the first can 221 has a first opening (not shown) opened in one side direction C1 on one side 221b and a first connection closed in the other side direction C2 on the other side 221c. A portion 221a may be formed. The second can 222 has a second opening 222d opened in the other side direction C2 on the other side 222c, and a second connecting part 222a closed in the one side direction C1 on the side 222b. good. At this time, the end of the first electrode 211 may be connected to the first connecting portion 221a, and the end of the second electrode 212 may be connected to the second connecting portion 222a.

The insulator 223 may include an insulating material to insulate the overlapping portion between the first can 221 and the second can 222 .

Also, the insulator 223 may have a through hole or a short-circuit induction through portion 123a-1 formed in the shape of a cut line. Here, the first can 221 and the second can 222 can be short-circuited through the short-circuit induction through portion 123a-1, which is deformed by the insulator 223 contracting or expanding under heat or pressure. ( See Figure 5) .

The first can 221 may include aluminum, and the second can 222 may include steel. Here, since the material of the second can 222 located inside the can 220 includes steel, it is easy to press-fit the first can 221 and the second can 222 together due to its high rigidity. Yes (in the present invention, the first and second cans are preferably press-fitted together), and it is easy to protect objects such as the electrode assembly 210 housed inside the can 220 when an external force is generated. can be In addition, since the first can 221 located on the outer side of the can 220 is made of aluminum having a high deformation rate, the insulator 223 is deformed when the first can 221 is deformed by an external force. 1 can be easily shorted between the first can 221 and the second can 222 ( see FIG. 5) .

At this time, the first electrode 211 may be a positive electrode, and the second electrode 212 may be a negative electrode.

Hereinafter, secondary batteries according to other embodiments will be described.

FIG. 12 is a perspective view showing a secondary battery according to still another embodiment of the present invention, and FIG. 13 is an exploded perspective view showing a secondary battery according to still another embodiment of the present invention.

12 and 13, a secondary battery 300 according to another embodiment of the present invention is an electrode in which a first electrode 311, a separator 314, and a second electrode 312 are alternately stacked and rolled up. The can 320 including the assembly 310 and the first can 321 and the second can 322 that house the electrode assembly 310 therein, and the insulator 323 that insulates the overlapping portion between the first can 321 and the second can 322. including.

A secondary battery 300 according to another embodiment of the present invention has a different shape of a can 310 when compared with the secondary battery according to the above-described embodiment and the secondary battery according to another embodiment. Therefore, this embodiment will omit or briefly describe the content that overlaps with the first embodiment, and will focus on the points of difference.

More specifically, in the secondary battery 300 according to still another embodiment of the present invention, the can 320 is formed in a cylindrical shape having openings facing each other and having a receiving portion for receiving the electrode assembly 310 therein. may include a first can 321 and a second can 322 that are connected to each other.

Here, the first can 321 may be electrically connected to the first electrode 311 and the second can 322 may be electrically connected to the second electrode 312 .

In addition, the first can 321 and the second can 322 are formed in a square tube shape, the inner width of the first can 321 is formed larger than the outer width of the second can 322, and the second can 322 may be inserted into

Further, the first can 321 has a first opening (not shown) opened in one side direction C1 on one side 321b and a first connection closed in the other side direction C2 on the other side 321c. A portion 321a may be formed. The second can 322 has a second opening 322d that opens in the other side direction C2 on the other side 322c, and a second connecting part 322a that closes in the one side direction C1 on the one side 322b. good. At this time, the end of the first electrode 311 may be connected to the first connecting portion 321a, and the end of the second electrode 312 may be connected to the second connecting portion 322a.

The insulator 323 may include an insulating material to insulate the overlapping portion between the first can 321 and the second can 322 .

Also, the insulator 323 may have a through hole or a short circuit induction through portion 323a formed in the shape of a cut line. Here, the first can 321 and the second can 322 can be short-circuited through the short-circuit induction through portion 323a deformed by the insulator 323 contracting or expanding under heat or pressure.

Meanwhile, in the secondary battery 300 according to another embodiment of the present invention, for example, the first can 321 may be made of steel, and the second can 322 may be made of aluminum.

Further, as another example, the first can 321 may include aluminum and the second can 322 may include steel.

Meanwhile, in the secondary battery 300 according to still another embodiment of the present invention, for example, the first electrode 311 may be a negative electrode and the second electrode 312 may be a negative electrode.

Furthermore, as another example, the first electrode 311 may be a positive electrode and the second electrode 312 may be a negative electrode.

<Production Example 1>
FIG. 14 is a diagram showing the displacement received by the can of the secondary battery according to Manufacturing Example 1. As shown in FIG.

A can having an electrode assembly and a housing portion for housing the electrode assembly therein, the can including a first can and a second can having cylindrical openings facing each other; A secondary battery made of an insulator and having a short-circuit induction penetrating portion formed in the shape of a penetrating hole that insulates the overlapping portion between the first can and the second can was manufactured.

Here, the outer can, which is the first can located outside, is made of steel, and the inner can, which is the second can located inside, is made of aluminum. Here, the thickness of the outer can is 0.1t (t=1 mm) and the thickness of the inner can is 0.1t.

The insulator is made of a polymer PP material and has a thickness of 0.1t (t=1mm).

The outer diameter of the inner can was formed to be 50 mm.

<Production Example 2>
FIG. 15 is a diagram showing the displacement received by the can of the secondary battery according to Manufacturing Example 2. As shown in FIG.

A can having an electrode assembly and a housing portion for housing the electrode assembly therein, the can including a first can and a second can having cylindrical openings facing each other; A secondary battery made of an insulator and having a short-circuit induction penetrating portion formed in the shape of a penetrating hole that insulates the overlapping portion between the first can and the second can was manufactured.

Here, the outer can, which is the first can located outside, is made of aluminum, and the inner can, which is the second can located inside, is made of steel. Here, the thickness of the outer can is 0.1t (t=1 mm) and the thickness of the inner can is 0.1t.

The insulator is made of PP material and has a thickness of 0.1t (t=1mm).

The outer diameter of the inner can was formed to be 50 mm.

<Comparative Example 1>
FIG. 16 is a diagram showing the displacement received by the can of the secondary battery according to Comparative Example 1. As shown in FIG.

A can having an electrode assembly and a housing portion for housing the electrode assembly therein, the can including a first can and a second can having cylindrical openings facing each other; A secondary battery composed of an insulator without a short-circuit-inducing penetrating portion formed in the shape of a penetrating hole that insulates the overlapping portion between the first can and the second can was manufactured.

Here, the outer can, which is the first can located outside, is made of steel, and the inner can, which is the second can located inside, is made of aluminum. Here, the thickness of the outer can is 0.1t (t=1 mm) and the thickness of the inner can is 0.1t.

The insulator is made of a polymer PP material and has a thickness of 0.1t (t=1mm).

The outer diameter of the inner can was formed to be 50 mm.

<Comparative Example 2>
FIG. 17 is a diagram showing the displacement received by the can of the secondary battery according to Comparative Example 2. As shown in FIG.

A can having an electrode assembly and a housing portion for housing the electrode assembly therein, the can including a first can and a second can having cylindrical openings facing each other; A secondary battery composed of an insulator without a short-circuit induction penetrating portion that insulates the overlapping portion between the first can and the second can was manufactured.

Here, the outer can, which is the first can located outside, is made of aluminum, and the inner can, which is the second can located inside, is made of steel. Here, the thickness of the outer can is 0.1t (t=1 mm) and the thickness of the inner can is 0.1t.

The insulator is made of a polymer PP material and has a thickness of 0.1t (t=1mm).

The outer diameter of the inner can was formed to be 50 mm.

<Experimental example>
The internal pressure acting on the can is 1.5 MPa, all of which act in the outward direction, and when the upper and lower surfaces are given the same constraint conditions, the displacement received by the inner can due to the pressure expanding from the inside to the outside of the battery is calculated. Indicated.

As a result of the experiment, referring to FIG. 14, a deformation amount of 0.30 3 65 mm occurs when the can made of aluminum (Al) of Manufacturing Example 1 is inside, and referring to FIG. 15, manufacturing example It can be seen that a deformation amount of 0.08009 mm occurred when the can made of steel (2) was inside. That is, when the can made of aluminum (Al) is inside, the elastic modulus is lower than that of the can made of steel, so it can be seen that the can expands more than when steel is inside. In addition, it can be expected that sufficient deformation will occur since firing deformation will occur. A larger expansion under the same conditions means that the deformation of the short-circuit induction penetration is larger under the same conditions. If the deformation of the short-circuit-inducing penetration is greater, short-circuiting between the first and second cans can occur more easily. However, when a can made of steel is inside, it may be easy to insert the cans (press-fitting process) into each other due to the physical properties of steel, which has a high rigidity.

In addition, referring to FIG. 16, when the aluminum (Al) can of Comparative Example 1 is inside, a deformation amount of 0.09127 mm occurs, and referring to FIG. 17, the steel of Comparative Example 2 It can be seen that a deformation amount of 0.03965 mm occurred when the can made of (Steel) material was inside.

Therefore, as shown in FIGS. 14 to 17, compared to Comparative Examples 1 and 2, an insulator having no short-circuit induction through portion formed in the shape of a through hole was provided between the outer can and the inner can. Further, in the manufacturing examples 1 and 2, in which the insulator having the short-circuit induction through portion formed in the shape of a through-hole was provided between the outer can and the inner can, more expansion occurred in the can. I understand.

In other words, a large expansion means that the deformation of the insulator is larger under the same conditions, and as a result, the deformation of the short-circuit induction through portion is greatly generated, so that the first can and the second can are easily short-circuited. I know it can happen.

Although the present invention has been described in detail through specific embodiments, this is for the purpose of specifically describing the present invention, and the secondary battery according to the present invention is not limited thereto. It can be said that various implementations are possible by those skilled in the art within the technical idea of the present invention.

Also, the specific protection scope of the invention should be clarified by the claims.

Claims (17)

an electrode assembly in which a first electrode, a separation membrane, and a second electrode are alternately laminated and wound;
A can having an accommodating portion for accommodating the electrode assembly therein, the can including a first can and a second can formed in a cylindrical shape with openings facing each other; and the first can. and an insulator insulating the overlapping portion between the second can;
the first can is electrically connected to the first electrode and the second can is electrically connected to the second electrode;
the insulator is formed with a through hole or a short-circuit induction through portion formed in the shape of a cut line;
A short circuit is formed between the first can and the second can via the short-circuit induction through portion, the shape of which is deformed by the insulator contracting or expanding under heat or pressure ,
The first can and the second can are cylindrically formed,
A secondary battery in which the inner peripheral surface of the first can is larger than the outer peripheral surface of the second can, and the second can is inserted into the first can . an electrode assembly in which a first electrode, a separation membrane, and a second electrode are alternately laminated and wound;
A can having an accommodating portion for accommodating the electrode assembly therein, the can including a first can and a second can formed in a cylindrical shape with openings facing each other; and
an insulator that insulates an overlapping portion between the first can and the second can;
the first can is electrically connected to the first electrode and the second can is electrically connected to the second electrode;
the insulator is formed with a through hole or a short-circuit induction through portion formed in the shape of a cut line;
A short circuit is formed between the first can and the second can via the short-circuit induction through portion, the shape of which is deformed by the insulator contracting or expanding under heat or pressure,
The first can and the second can are formed in a square tubular shape,
The secondary battery, wherein the inner width of the first can is larger than the outer width of the second can, and the second can is inserted into the first can. The secondary battery of claim 1 or 2 , wherein a plurality of the short-circuit induction through-holes are formed. 4. The secondary battery of claim 3 , wherein the short-circuit induction through-holes are formed in at least one column or row in the insulator. 4. The secondary battery according to claim 3 , wherein said short-circuit induction through-holes are formed in said insulator in a grid pattern. The secondary battery according to any one of claims 1 to 5 , wherein the insulator comprises a polymer material. 7. The secondary battery of claim 6 , wherein the polymer material is one of PE, PP and PET. The secondary battery of claim 6 , wherein the polymer material is made of PE or PP material having a melting point below 180C. The secondary battery according to any one of claims 1 to 8 , wherein the insulator is coated on the outer peripheral surface of the second can to form a coating layer. 9. The insulator is attached to the outer peripheral surface of the second can by any one of painting, printing, cladding, lamination, spraying, masking, dipping, and bonding . 1. The secondary battery according to item 1 . The first can is formed with a first opening that is open in one side on one side and a first connection that is closed in the other side on the other side,
The second can is formed with a second opening opening in the other side direction on the other side, and a second connection part closed in the one side direction is formed on the one side,
11. The secondary according to any one of claims 1 to 10, wherein an end of said first electrode is connected to said first connection and an end of said second electrode is connected to said second connection. battery. 12. The secondary battery of claim 11, wherein the one side end of the insulator is extended to be positioned closer to the second connecting part than the one side end of the first can. 13. The secondary battery of claim 11, wherein the other end of the insulator extends to be positioned closer to the first connecting part than the other end of the second can. . the first can includes steel,
The secondary battery according to any one of claims 1 to 13, wherein said second can is formed containing aluminum. The first can is formed containing aluminum,
The secondary battery according to any one of claims 1 to 13, wherein the second can comprises steel. 15. The secondary battery of claim 14, wherein the first electrode is a negative electrode and the second electrode is a positive electrode. 16. The secondary battery of claim 15, wherein the first electrode is a positive electrode and the second electrode is a negative electrode.

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