KR20220043784A - Button type secondary battery - Google Patents

Abstract

The present invention relates to a button-type secondary battery, in which sealing performance of the button-type secondary battery is significantly increased so that gas does not leak out of the battery even if an excessive internal pressure is generated by the gas generated inside the battery, an electrolyte is prevented from leaking out of the battery, and space efficiency is maximized. According to the present invention, the button-type secondary battery has a diameter greater than a height thereof, and comprises an electrode assembly, a lower can into which the electrode assembly is inserted, and an upper can covering an upper opening of the lower can. The lower can includes a bottom part disposed on the lower part of the electrode assembly, and a wall part extending upward from the periphery of the bottom part. The upper can includes a planar part disposed on the upper part of the electrode assembly, a protrusion part extending upward from the periphery of the planar part, and a side wall part extending downward from the protrusion part and disposed to surround the wall part from the outside of the wall part, wherein the upper can and the lower are coupled so that the upper end of the wall part is located in the inner space of the protrusion part.

Description

Button type secondary battery {BUTTON TYPE SECONDARY BATTERY}

The present invention relates to a button-type secondary battery, and as the sealing performance of the button-type battery is significantly improved, the gas does not leak out of the battery even if excessive internal pressure is generated by the gas generated inside the battery, and the electrolyte It relates to a button-type secondary battery capable of preventing leakage to the outside and maximizing space efficiency.

In recent years, the increase in the price of energy sources due to the depletion of fossil fuels and the interest in environmental pollution are increasing, and the demand for eco-friendly alternative energy sources is becoming an indispensable factor for future life. Accordingly, research on various power generation technologies such as solar power, wind power, and tidal power continues, and power storage devices such as batteries for more efficient use of the generated electrical energy are also of great interest.

Furthermore, as technology development and demand for electronic mobile devices and electric vehicles using batteries increase, the demand for batteries as an energy source is rapidly increasing, and accordingly, a lot of research on batteries that can meet various needs is being conducted. there is.

In particular, in terms of materials, there is a high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries having advantages such as high energy density, discharge voltage, and output stability.

According to the shape of the battery case, secondary batteries are classified into cylindrical batteries and prismatic batteries in which the electrode assembly is embedded in a cylindrical or prismatic metal can, and pouch-type batteries in which the electrode assembly is embedded in a pouch-type case of an aluminum laminate sheet. can be And recently, in line with the trend of miniaturization of wearable devices, the importance of developing small batteries such as button-type secondary batteries has been highlighted.

1 is a cross-sectional view showing a conventional button-type secondary battery.

Referring to FIG. 1 , the conventional button-type secondary battery 10 has an upper and a lower housing divided, and the shape is in the form of an upper cylindrical can 4 and a lower cylindrical can 3 fitted. That is, the outer diameter of the upper cylindrical can 4 is slightly larger than that of the lower cylindrical can 3, and the two cans are fitted with each other with the gasket 5 interposed therebetween. In the case of the press fit type, it is the principle that the shape of the button type secondary battery is maintained due to the friction force that is fitted. In addition, in the conventional button-type secondary battery, the upper cylindrical can 4 and the lower cylindrical can 3 were manufactured to fit the size of the internal electrode assembly 1 and fitted, so there was no extra space inside.

However, since there is no fixing force other than frictional force when the internal pressure increases due to generation of internal gas, etc., there is a high possibility that the upper cylindrical can 4 and the lower cylindrical can 3 are separated. When the internal pressure rises, it may rise due to a side reaction, but it may also rise during a normal cycle. If the internal pressure rises excessively, gas and electrolyte will leak. could not fulfill its role as

Therefore, there was a need to research a product in which gas or electrolyte does not leak despite the internal reaction of the battery and the upper and lower cans cannot be separated.

The present invention has been devised to solve the above problems, and the object of the present invention is to significantly improve the sealing performance of the button-type battery, so that even if excessive internal pressure is generated by the gas generated inside the battery, the gas It is to prevent leakage to the outside, to prevent electrolyte from leaking out of the battery, and to provide a button-type secondary battery capable of maximizing space efficiency.

The button-type secondary battery according to the present invention relates to a button-type secondary battery in which the length of the diameter is greater than the height, comprising an electrode assembly, a lower can into which the electrode assembly is inserted, and an upper can covering the upper opening of the lower can, the lower can comprising: A bottom portion placed under the electrode assembly, and a wall portion extending upwardly from the periphery of the bottom portion, wherein the upper can includes a flat portion positioned on the upper portion of the electrode assembly, a protrusion extending upward from the periphery of the flat portion, and a protrusion The upper can and the lower can are coupled to each other so that an upper end of the wall portion is located in the inner space of the protrusion, and includes a side wall portion extending downward from the wall portion and disposed to surround the wall portion from the outside of the wall portion.

The protrusion includes a first extension extending from the periphery of the planar portion and extending in an upward direction, a second extension portion extending outwardly from the first extension in a radial direction, and a third extending portion extending downward from the second extension portion. It may include an extension.

Further comprising an insulator for preventing the upper can and the lower can from contacting each other, the insulator and the upper end of the wall portion are located together in the inner space of the protrusion surrounded by the first extension, the second extension, and the third extension can do.

The insulator includes a first insulator portion located inside the top of the wall portion, a second insulator portion extending from the first insulator portion and covering over the top of the wall portion, and a third insulator extending from the second insulator portion and located outside the top of the wall portion It may contain parts.

The first insulator part, the upper end of the wall part, and the third insulator part may be positioned between the first extension part and the third extension part, and the first extension part and the third extension part may be compressed in a direction approaching each other.

By compression, the first insulator portion and the third insulator portion may be thinner than the second insulator portion.

The sidewall portion includes a first sidewall portion extending downward from the third extension portion, an inclined portion extending from the first sidewall portion in a direction approaching the wall portion, and a second portion extending downward in a vertical direction from an end of the inclined portion. It may include a sidewall portion.

The electrode assembly is a jelly roll type electrode assembly in which electrodes and separators are alternately stacked and wound, and a center hole is formed in the center of the electrode assembly, and a center pin may be provided in the center hole to fill the center hole.

It may further include an electrode tab connecting the electrode of the electrode assembly and the flat portion of the upper can, one end of the electrode tab connected to the electrode of the electrode assembly, and the other end of the electrode tab connected to the lower surface of the flat portion in a C-shape.

The height of the protrusion measured with respect to the flat portion of the upper can may be lower than the height of the upper end of the wall portion measured with respect to the bottom of the lower can.

An indentation space may be formed in the upper can surrounded by the flat portion and the first extension.

Additional components can be mounted within the recessed space.

The additional component may be a PCB circuit board.

The upper surface of the additional part and the upper surface of the second extension may be connected to a plane without a step difference.

The button-type secondary battery according to the present invention relates to a button-type secondary battery in which the length of the diameter is greater than the height of the button-type secondary battery, and the electrode assembly, the lower can into which the electrode assembly is inserted, and the upper part covering the upper opening of the lower can a can, wherein the lower can includes a bottom portion placed under the electrode assembly, and a wall portion extending upwardly from the outer periphery of the bottom portion, and the upper can includes a flat portion located on the upper portion of the electrode assembly, and an upper side from the outer portion of the flat portion The upper can and the lower can are coupled to each other so that an upper end of the wall portion is located in the inner space of the protrusion, comprising: a protrusion extending in the direction; The button-type secondary battery according to the present invention significantly improves the sealing performance of the button-type battery by having these features, so that even if excessive internal pressure is generated by the gas generated inside the battery, the gas does not leak out of the battery. , it is possible to prevent the electrolyte from leaking out of the battery, and also to maximize space efficiency.

1 is a cross-sectional view showing a conventional button-type secondary battery.
2 is a cross-sectional view illustrating a button-type secondary battery according to Embodiment 1 of the present invention.
3 is a cross-sectional view illustrating a state in which the protrusion is pressed in the button-type secondary battery according to the first embodiment of the present invention.
4 is a cross-sectional view illustrating a button-type secondary battery according to a second embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily carry out the present invention. However, the present invention may be implemented in several different forms and is not limited or limited by the following examples.

In order to clearly explain the present invention, detailed descriptions of parts irrelevant to the description or related known technologies that may unnecessarily obscure the gist of the present invention have been omitted, and in the present specification, reference signs are added to the components of each drawing. In this case, the same or similar reference numerals are assigned to the same or similar elements throughout the specification.

In addition, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor appropriately defines the concept of the term in order to best describe his invention. Based on the principle that it can be done, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

Example 1

2 is a cross-sectional view illustrating a button-type secondary battery according to Embodiment 1 of the present invention. 3 is a cross-sectional view illustrating a state in which the protrusion is pressed in the button-type secondary battery according to the first embodiment of the present invention.

Referring to FIG. 2 , the button-type secondary battery according to Example 1 of the present invention may be a battery having a cylindrical shape, and the diameter of the cylindrical battery may be larger than the height of the battery.

In addition, the button-type secondary battery 100 according to Embodiment 1 of the present invention may include an electrode assembly 150 , a lower can 110 , and an upper can 130 . The electrode assembly 150 may be in the form of a jelly roll in which the electrodes 151 and the separator 152 are alternately stacked and wound.

And the electrode assembly 150 may be inserted into the lower can (110). The lower can 110 may have an open top in a cylindrical shape. The electrode assembly 150 may be in the form of a jelly roll. When the electrode assembly 150 is disposed on the lower can 110 , the winding axis of the electrode assembly 150 may be disposed in a form perpendicular to the ground. The upper can 130 may have a shape that covers the upper opening of the lower can 110 .

The lower can 110 may include a bottom portion 111 and a wall portion 112 . The bottom part 111 may be placed under the electrode assembly 150 . The wall portion 112 may be a portion of the lower can 110 extending upwardly from the outer portion of the bottom portion 111 . The wall portion 112 may be a portion surrounding the electrode assembly 150 from the side of the electrode assembly 150 .

The upper can 130 may include a flat portion 131 , a protrusion 132 , and a sidewall portion 133 . The flat portion 131 may be a flat portion positioned on the electrode assembly 150 . The protrusion 132 may be a portion extending upwardly from the periphery of the flat portion 131 . In addition, it may have a shape protruding upward. Accordingly, an inner space may be formed inside the protrusion 132 . The side wall part 133 extends downward from the protrusion part 132 and is located outside the wall part 112 of the lower can 110 , and is a part of the upper can 130 that is disposed to surround the wall part 112 . can

In addition, in the button-type secondary battery 100 according to the first embodiment of the present invention, the upper end 113 of the wall portion of the lower can 110 may be located in the inner space of the protrusion 132 of the upper can 130 . That is, the upper can 130 and the lower can 110 may be coupled such that the upper end 113 of the wall portion is positioned in the inner space of the protrusion 132 .

If the coupling is made in this way, even if there is a situation in which gas or electrolyte in the internal space of the battery leaks, since a structure is created that has to turn around as much as the length of the protrusion 132 , the leakage of gas or electrolyte may become that much more difficult. Therefore, this may be a structure that prevents leakage of gas or electrolyte.

In addition, in the button-type secondary battery 100 according to Embodiment 1 of the present invention, the protrusion 132 may include a first extension 132a, a second extension 132b, and a third extension 132c. can The first extension portion 132a may be a portion extending in an upward direction while continuing from the periphery of the flat portion 131 . The second extension 132b may be a portion extending outward from the first extension 132a in a radial direction. In addition, the second extension 132b may be a portion connecting the first extension 132a and the third extension 132c. Also, the third extension 132c may be a portion extending downward from the end of the second extension 132b.

The button-type secondary battery 100 according to the first embodiment of the present invention may further include an insulator 170, which is used to prevent the upper can 130 and the lower can 110 from contacting each other. it could be As an example, a gasket may be used.

And, the inner space of the protrusion 132 may be a space surrounded by the first extension 132a, the second extension 132b, and the third extension 132c. In this inner space, the insulator 170 and the upper end 113 of the wall part may be located together. When positioned in this way, since the insulator 170 has a structure sandwiched between the first extension part 132a, the second extension part 132b, and the third extension part 132c and the upper end 113 of the wall part, it is necessary for sealing. It could be more helpful.

The insulator 170 may specifically include a first insulator portion 171 , a second insulator portion 172 , and a third insulator portion 173 . The first insulator portion 171 may be a portion located inside the upper end 113 of the wall portion. The second insulator portion 172 may be a portion extending from the first insulator portion 171 and covering the upper end 113 of the wall portion. The third insulator portion 173 may be a portion extending from an end of the second insulator portion 172 and positioned outside the upper end 113 of the wall portion. With this structure, the first insulator part 171 , the upper end of the wall part 113 , and the third insulator part 173 may be positioned between the first extension part 132a and the third extension part 132c . .

2 and 3 , in the button-type secondary battery 100 according to Embodiment 1 of the present invention, in particular, the first extension part 132a and the third extension part 132c may be compressed in a direction closer to each other. there is. This may be formed by applying a compressive force to the protrusion 132 in a radial direction. When pressure is applied like the arrow in the F direction of FIG. 2 , as shown in FIG. 3 , the first extension part 132a and the third extension part 132c may be compressed in a direction closer to each other. When compressed as described above, the first insulator part 171 and the third insulator part 173 may be formed to have a thinner thickness than the second insulator part 172 by the compression.

In this case, in a situation where the gas or electrolyte is about to leak, the effect of making the leak path complicated and long is exhibited, and at the same time, the effect of blocking the leak path by strong compression comes out. Accordingly, it is possible to significantly improve the sealing performance of the button-type former paper.

If the sealing performance of the button-type battery is significantly improved, it is possible to prevent the gas from leaking out of the battery even if excessive internal pressure is generated by the gas generated inside the battery, and to prevent the electrolyte from leaking out of the battery .

On the other hand, in the button-type secondary battery 100 according to the first embodiment of the present invention, since the protrusion direction of the protrusion 132 is upward (height direction) rather than the lateral direction (diameter direction), a button-type secondary battery capable of maximizing space efficiency (100) can be implemented. For example, when assembling a finished product using a battery such as a wireless earphone, it can have an advantage in miniaturization.

Since the button-type secondary battery 100 has a larger radial length in the height direction, forming the protrusion 132 in the radial direction further increases the maximum product length. However, when the protrusion 132 is formed in the height direction, the maximum length of the product does not change.

Meanwhile, in the button-type secondary battery 100 according to the first exemplary embodiment of the present invention, the sidewall part 133 may include a first sidewall part 133a, an inclined part 133b, and a second sidewall part 133c. . The first sidewall portion 133a may be a portion that continues from the third extension portion 132c and extends downward. The inclined portion 133b may be a portion extending from the first sidewall portion 133a in a direction closer to the wall portion 112 . The second sidewall portion 133c may be a portion extending downward in a vertical direction from an end of the inclined portion 133b.

In this case, the wall portion 112 of the lower can 110 also faces the first sidewall portion 133a, the inclined portion 133b, and the second sidewall portion 133c. It may be formed in a shape corresponding to the shape of the portion 133b and the second sidewall portion 133c. When the upper can 130 and the lower can 110 are formed in this way, a predetermined space is created on the side of the electrode assembly 150 .

The side space of the electrode assembly 150 may be utilized in various ways. First, if it is used as a space to inject more electrolyte, the performance of the battery can be improved. And this space can also be used as a space to attach the swelling tape.

The swelling tape may be a tape whose volume expands when it absorbs an electrolyte. When the swelling tape with expanded volume is positioned on the side of the electrode assembly 150, the effect of protecting the electrode assembly 150 from external impact can get

On the other hand, in the button-type secondary battery 100 according to the first embodiment of the present invention, a center hole 154 is formed in the center of the electrode assembly 150, and the center hole 154 is filled with the center hole 154 in the center hole 154. A pin 190 may be provided.

When the center pin 190 is formed to completely fill the center hole 154 , it is possible to prevent the electrode assembly 150 from being deformed. As the battery reaction proceeds, the core portion of the electrode assembly 150, which has a particularly weak support, may be deformed by internal heat and internal gas generated. As a result, a short-circuit accident such as an anode and a cathode meeting may occur. However, in the present invention, since the center pin 190 is provided so that the center hole 154 is full, the occurrence of such a short-circuit accident can be prevented in advance.

In addition, in the button-type secondary battery 100 according to Embodiment 1 of the present invention, an electrode tab 153 connecting the electrode 151 of the electrode assembly 150 and the upper can may be further included. ) may be connected to the electrode 151 of the electrode assembly 150 , and the other end of the electrode tab 153 may be connected to the upper can flat part 131 in a C-shape. As shown in FIG. 3 , when the electrode tab 153 is connected to the lower surface of the upper can flat part 131 in a C-shape, it may have some elasticity in the case of an impact such as a drop, so even if an impact such as a drop occurs, the electrode tab ( 153) can be effectively prevented from breaking.

Example 2

4 is a cross-sectional view illustrating a button-type secondary battery according to a second embodiment of the present invention.

Embodiment 2 of the present invention may be different from Embodiment 1 in that an additional component 240 may be further mounted in the space on the upper can 230 .

The contents common to the first embodiment will be omitted as much as possible and the second embodiment will be described with a focus on the differences. That is, it is obvious that, if the content not described in the second embodiment is necessary, it may be regarded as the content of the first embodiment.

Referring to FIG. 4 , in the button-type secondary battery 200 according to the second embodiment of the present invention, the height of the protrusion 232 measured with respect to the flat part 231 of the upper can 230 is the lower can 210 . It may be lower than the height of the upper end 213 of the wall portion measured with respect to the bottom portion 211 of the .

In addition, an indentation space C surrounded by the flat part 231 and the first extension part 232a may be formed in the upper can 230 . This recessed space (C) may have a smaller volume than the internal space of the battery containing the electrode assembly (250).

An additional component 240 may be mounted in the recessed space C. The additional component 240 mounted in the recessed space C may be a printed circuit board (PCB) circuit board, or a protection circuit module.

As such, in the button-type secondary battery 200 according to the second embodiment of the present invention, a depression space C is formed, and an additional component 240 suitable for use in the button-type secondary battery may be mounted in the depression space C. Through this, the button-type cell can have different uses and can maximize space efficiency.

Meanwhile, referring to FIG. 4 , the upper surface of the additional component 240 and the upper surface of the second extension part 232b may be connected to a flat surface without a step difference. This may mean that the height of the protrusion 232 measured with respect to the flat portion 231 is the same as the height of the additional component 240 .

If the additional component 240 protrudes upward more than the protrusion 232 , the additional component 240 may easily collide with an external object and receive an impact. However, as in the second embodiment of the present invention, if the upper surface of the additional part 240 and the upper surface of the second extension part 232b are connected to a plane without a step difference, the additional part 240 does not collide with other external objects. can be protected.

In the above, although the present invention has been described with reference to limited examples and drawings, the present invention is not limited thereto, and it is described below with the technical idea of the present invention by those of ordinary skill in the art to which the present invention pertains. Various implementations are possible within the scope of equivalents of the claims to be made.

100, 200: button type secondary battery
110, 210: lower can
111, 211: bottom part
112, 212: wall part
113, 213: upper end of the wall part
130, 230: upper can
131, 231: flat part
132, 232: protrusions
132a, 232a: first extension
132b, 232b: second extension
132c, 232c: third extension
133, 233: side wall portion
133a, 233a: first sidewall portion
133b, 233b: inclined portion
133c, 233c: second sidewall portion
150, 250: electrode assembly
151, 251: electrode
152, 252: separator
153, 253: electrode tab
154, 254: central hall
170, 270: insulator
171, 271: first insulator portion
172, 272: second insulator portion
173, 273: third insulator portion
190: center pin
240: additional parts
C: indentation space

Claims (14)

In a button-type secondary battery in which the length of the diameter is greater than the height,
electrode assembly;
a lower can into which the electrode assembly is inserted; and
an upper can covering the upper opening of the lower can;
The lower can includes a bottom portion placed under the electrode assembly, and a wall portion extending upwardly from the periphery of the bottom portion,
The upper can includes a flat portion positioned on the upper portion of the electrode assembly, a protrusion extending upwardly from the periphery of the planar portion, and a sidewall portion extending downwardly from the protrusion and disposed to surround the wall portion from the outside of the wall portion and
The button type secondary battery in which the upper can and the lower can are coupled so that the upper end of the wall part is located in the inner space of the protrusion. The method according to claim 1,
The protrusion includes a first extension extending from the periphery of the flat portion and extending in an upward direction, a second extension extending outward from the first extension in a radial direction, and a downward direction from the second extension A button-type secondary battery comprising a third extension that extends. 3. The method according to claim 2,
Further comprising an insulator for preventing the upper can and the lower can from contacting each other,
The button type secondary battery, characterized in that the upper end of the insulator and the wall portion are located together in the inner space of the protrusion surrounded by the first extension, the second extension, and the third extension. 4. The method according to claim 3,
The insulator includes a first insulator portion located inside the upper end of the wall portion, a second insulator portion extending from the first insulator portion and covering the upper end of the wall portion, and extending from the second insulator portion and outside the upper end of the wall portion A button-type secondary battery comprising a third insulator portion located in the. 5. The method according to claim 4,
The first insulator part, the upper end of the wall part, and the third insulator part are positioned between the first extension part and the third extension part;
The button type secondary battery, characterized in that the first extension and the third extension are pressed in a direction closer to each other. 6. The method of claim 5,
The button type secondary battery, characterized in that the thickness of the first insulator part and the third insulator part is thinner than that of the second insulator part by the compression. 3. The method according to claim 2,
The sidewall portion includes a first sidewall portion extending downwardly from the third extension portion, an inclined portion extending from the first sidewall portion in a direction approaching the wall portion, and a lower side in a vertical direction from an end of the inclined portion A button-type secondary battery comprising a second sidewall portion extending to the The method according to claim 1,
The electrode assembly is a jelly roll-type electrode assembly in which electrodes and separators are alternately stacked and wound,
A central hole is formed in the center of the electrode assembly,
A button type secondary battery having a center pin in the center hole to fill the center hole. 9. The method of claim 8,
Further comprising an electrode tab connecting the electrode of the electrode assembly and the flat portion of the upper can,
One end of the electrode tab is connected to the electrode of the electrode assembly,
The other end of the electrode tab is a button type secondary battery, characterized in that connected to the lower surface of the flat portion in a C-shape. 3. The method according to claim 2,
The height of the protrusion measured with respect to the flat part of the upper can,
A button-type secondary battery, characterized in that it is lower than the height of the upper end of the wall portion measured with respect to the bottom portion of the lower can. 11. The method of claim 10,
The button type secondary battery, characterized in that the upper can is formed with a recessed space surrounded by the flat portion and the first extension portion. 12. The method of claim 11,
A button-type secondary battery, characterized in that an additional component is mounted in the recessed space. 13. The method of claim 12,
The additional component is a button type secondary battery, characterized in that the PCB circuit board. 13. The method of claim 12,
A button-type secondary battery, characterized in that the upper surface of the additional part and the upper surface of the second extension part are connected in a plane without a step difference.

Images