KR20220037339A - Button type secondary battery - Google Patents

Abstract

The present invention relates to a button-type secondary battery, which makes it that a battery is not separated by the gas pressure or the gas harmful to the human body is not leaked out of the battery even if excessive internal pressure is generated by the gas generated inside a battery, has a strong bond which prevents an electrolyte from leaking out of the battery, maximizes the battery capacity and energy density by improving the volume ratio of an electrode assembly in the battery, and increases production efficiency by simplifying and conveniently manufacturing a battery. The button-type secondary battery, according to the present invention, has a diameter greater than a height, and comprises: an electrode assembly; a lower can into which an electrode assembly is inserted, and which has a first screw thread formed on an outer circumferential surface thereof; an upper can which covers an upper opening of the lower can, and includes a second screw thread corresponding to the first screw thread formed on an inner circumferential surface thereof; and an insulator interposed between the upper can and the lower can to prevent a short circuit between the upper and lower cans. The electrode assembly is formed by horizontally stacking a plurality of first electrodes, a separator, and a second electrode, and a first electrode tab connected to and extending from the first electrode of the electrode assembly contacts the upper can.

Description

Button type secondary battery {BUTTON TYPE SECONDARY BATTERY}

The present invention relates to a button-type secondary battery, which prevents the battery from being separated by the gas pressure or gas harmful to the human body from leaking out of the battery even if excessive internal pressure is generated by the gas generated inside the battery, and electrolyte is leaked to the outside of the battery A button-type secondary battery that has a strong bond that prevents it from coming out, can maximize the battery capacity and energy density by improving the volume ratio occupied by the electrode assembly in the battery, and can increase production efficiency by simplifying the battery manufacturing process and making it convenient is about

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-shaped secondary battery 10 has an upper and a lower housing divided, and the shape of the upper cylindrical can 4 and the lower cylindrical can 3 is in the form of an interference fit. . That is, the outer diameter of the lower cylindrical can 3 was slightly larger than that of the upper portion to form an interference fit with each other. In the case of the forced fitting type, the shape of the button type secondary battery is maintained due to the friction force that is fitted. In addition, in the conventional button-shaped secondary battery, the upper can 4 and the lower 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 can 4 and the lower 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. Therefore, it was necessary to study a product in which the upper and lower cans could not be separated because they were combined by a strong bond.

Also, referring to FIG. 1 , in the prior art, the electrode assembly 1 inside the battery was a jelly roll type electrode assembly manufactured by winding an electrode and a separator. The electrode assembly 1 was disposed in a form in which the winding axis was perpendicular to the ground. However, when the battery is formed in this way, a central hole is formed in the center of the electrode assembly due to the winding core, which is a tool for performing winding. That is, a space that does not produce electricity was formed in the center of the electrode assembly. This could be an inefficient factor for a button-type battery that is small in size, limited, and widely used in the wearable device market. Accordingly, there was a need for research to secure an improved capacity.

The present invention has been devised to solve the above problems, and the object of the present invention is to prevent the battery from being separated by the gas pressure or gas harmful to the human body from leaking out of the battery even if excessive internal pressure is generated by the gas generated inside the battery. It has a strong bond that prevents the electrolyte from leaking out of the battery, and it can maximize the battery capacity and energy density by improving the volume ratio that the electrode assembly occupies in the battery, and makes the battery manufacturing process simple and convenient. To provide a button-type secondary battery capable of increasing 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. , an upper can having a second screw thread corresponding to the first screw thread formed on an inner circumferential surface thereof, and an insulator interposed between the upper can and the lower can to prevent a short circuit between the upper can and the lower can, wherein the electrode assembly includes a plurality of first cans; A first electrode, a separator, and a second electrode are horizontally stacked and formed, and a first electrode tab connected to the first electrode of the electrode assembly and extending is in contact with the upper can.

The upper can is connected to the first electrode of the electrode assembly through the first electrode tab to form a terminal connected to an external device, and includes an upper can electrode terminal part covering the upper opening of the lower can, the first electrode tab comprising: a support part connected to the plurality of first electrodes of the electrode assembly; and a contact portion extending from the support portion and contacting the upper can electrode terminal portion.

The first electrode may include: a first electrode holding member in which an electrode active material is applied to an electrode current collector; and a first electrode uncoated portion extending laterally from the first electrode holding portion and comprising only an electrode current collector without applying an electrode active material, wherein the support portion may be connected to the plurality of first electrode uncoated portions.

The plurality of first electrode uncoated areas may be bonded to each other to form a first electrode uncoated area bundle, and the support part may be connected to the first electrode uncoated area bundle.

The support part may be formed in a bar shape, and the contact part may be formed in a circular ring shape.

The thickness of the contact part having the circular ring shape may be thicker than the thickness of the support part.

The support part may be formed in a bar shape, and the contact part may be formed in a disk shape.

The outer circumferential diameter of the contact portion formed in the circular ring shape and the outer circumferential diameter of the electrode assembly may have sizes corresponding to each other.

The insulator may be a PBT (polybutylene terephthalate) material.

The insulator may include an inner insulator positioned inside the lower can, an outer insulator positioned outside the lower can, and a connection insulator connecting the inner insulator and the outer insulator.

The upper can and the lower can are screwed by first and second threads, and the outer insulator is interposed between the first and second threads, and the outer insulator is in the protruding shape of the first and second threads. It may be pressed by the concave-convex shape and sandwiched between the first screw thread and the second screw thread.

The inner insulator may be positioned between the first electrode tab and the lower can to prevent contact between the first electrode tab and the lower can.

The separator may be a safety reinforced separator (SRS) single-sided coated separator.

The plurality of first electrodes, separators, and second electrodes may have a circular shape and are horizontally stacked, and the entire stack may be vertically joined by heat and pressure.

The outermost first electrode disposed at the outermost portion of the electrode assembly may be in contact with a lower surface of the first electrode tab.

The outermost first electrode disposed on the outermost side of the electrode assembly may be in contact with the lower surface of the contact part.

The outermost first electrode may be a single-sided electrode in which the electrode active material is not coated on the outer surface facing the upper can and only the inner surface is coated with the electrode active material.

An end of the upper can may be bent in a central axis direction of the lower can.

The outer insulator may extend downward along the outer wall of the lower can, and the end of the outer insulator may be longer than the end of the upper can and extend downward.

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. , an upper can having a second screw thread corresponding to the first screw thread formed on an inner circumferential surface thereof, and an insulator interposed between the upper can and the lower can to prevent a short circuit between the upper can and the lower can, wherein the electrode assembly includes a plurality of first cans; A first electrode, a separator, and a second electrode are horizontally stacked and formed, and a first electrode tab connected to the first electrode of the electrode assembly and extending is in contact with the upper can. Accordingly, even if excessive internal pressure is generated by the gas generated inside the battery, the gas pressure prevents the battery from being separated or gases harmful to the human body from leaking out of the battery, and has a strong bond that prevents the electrolyte from leaking out of the battery, By improving the volume ratio occupied by the electrode assembly in the battery, the battery capacity and energy density can be maximized, and the production efficiency can be increased by simplifying the battery manufacturing process and making it convenient.

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 perspective view separately illustrating only the electrode assembly and the first electrode tab in the button-type secondary battery according to Example 1 of the present invention shown in FIG. 2 .
4 is a plan view separately showing only the first electrode and the second electrode in the button-type secondary battery according to the first embodiment of the present invention.
5 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 perspective view separately illustrating only the electrode assembly and the first electrode tab in the button-type secondary battery according to Example 1 of the present invention shown in FIG. 2 . 4 is a plan view separately showing only the first electrode and the second electrode in the button-type secondary battery according to the first embodiment of the present invention.

Referring to FIG. 2 , the button-type secondary battery 100 according to Embodiment 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 includes an electrode 151 . 152) and the separator may be alternately disposed. In particular, the electrode assembly 150 may be formed by horizontally stacking a plurality of first electrodes 151 , a separator 153 , and a second electrode 152 .

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 stack in which disk-shaped electrodes 151. 152 and a separator 153 are stacked (refer to FIGS. 3 and 4). When the electrode assembly 150 is disposed on the lower can 110 , the first electrode 151 and the second electrode 152 of the electrode assembly 150 may be horizontally disposed on the ground.

In the button-type secondary battery 100 according to the first embodiment of the present invention, the lower can 110 may have a first screw thread 111 formed on an outer peripheral surface thereof. In addition, the upper can 130 may have a shape that covers the upper opening of the lower can 110 . A second screw thread 132 corresponding to the first screw thread 111 may be formed on the inner circumferential surface of the upper can 130 . The first screw thread 111 and the second screw thread 132 may have a relationship in which the upper can 130 and the lower can 110 are screwed to each other when they are coupled. That is, when the upper can 130 is covered and coupled to the lower can 110 , the upper can 130 may be rotated with respect to the lower can 110 so as to be screwed together, rather than being coupled as it is by pressing. When the upper can 130 rotates relative to the lower can 110 , the first screw thread 111 and the second screw thread 132 are screwed to each other, and the upper can 130 is the lower can 110 . become close to each other, and when the screw coupling is finished, the button-type secondary battery 100 in which the upper can 130 and the lower can 110 are completely coupled can be made. 2 shows a state in which the screw coupling of the upper can 130 and the lower can 110 is completed.

An insulator 170 interposed between the upper can 130 and the lower can 110 of the button-type secondary battery 100 according to the first embodiment of the present invention to prevent a short circuit between the upper can 130 and the lower can 110 . include The insulator 170 may include an inner insulator 171 , a connection insulator 172 , and an outer insulator 173 . The inner insulator 171 may be an insulator portion positioned inside the lower can 110 . The outer insulator 173 may be a portion of the insulator positioned outside the lower can 110 . In addition, the connection insulator 172 may be an insulator connecting the inner insulator 171 and the outer insulator 173 .

The insulator 170 may be interposed over the upper end of the lower can 110 . That is, the connection insulator 172 may be positioned to cover the upper end of the lower can 110 , and the inner insulator 171 may be positioned to contact the inner periphery of the upper end of the lower can. In addition, the outer insulator 173 may be positioned so as to be in contact with the outer periphery of the upper end of the lower can 110 . In addition, the outer insulator 173 may be formed to be longer than the inner insulator 171 .

Referring to FIG. 2 , the upper can 130 and the lower can 110 are screwed together by a first screw thread 111 and a second screw thread 132 , and the outer insulator 173 is a first screw thread 111 . Interposed between and the second screw thread 132, the outer insulator 173 is pressed by the protrusion shape of the first screw thread 111 and the second screw thread 132 to have a concave-convex shape with the first screw thread 111 and It may be sandwiched between the second screw threads 132 .

Meanwhile, the end 131 of the upper can may have the same height as the end 173a of the outer insulator (see FIG. 2 ), or the end 173a of the outer insulator has a lower height than the end 131 of the upper can. may have The fact that the end 173a of the outer insulator has a lower height than the end 131 of the upper can means that the end 173a of the outer insulator is closer to the bottom surface of the lower can 110 than the end 131 of the upper can. It may mean that it is located in

The process of combining the upper can 130 and the lower can 110 is as follows. First, the lower can 110 in which the electrode assembly 150 is inserted may be placed, and the insulator 170 may be coupled to the lower can 110 in a manner that covers the upper end of the lower can 110 . The connection insulator 172 is positioned to cover the upper end of the lower can 110 , the inner insulator 171 is in contact with the inner periphery of the upper end of the lower can, and the outer insulator 173 is in contact with the outer periphery of the upper end of the lower can 110 . In this state, the insulator 170 may be coupled to the lower can 110 . And it can be coupled by rotating the upper can 130 thereon. That is, the inner circumferential surface of the upper can 130 may be screwed by turning while contacting the outer circumferential surface of the outer insulator 173 . In this process, since the first screw thread 111 and the second screw thread 132 form a protruding thread, the outer insulator 173 is pressed by the protruding shape of the first screw thread 111 and the second screw thread 132 to be uneven. can have a form. In FIG. 2 , it is shown that the outer thread has a concave-convex shape.

Since this is coupled by applying a very strong pressure, the upper can 130 is not easily separated from the lower can 110 , and a strong coupling may be possible. Accordingly, even if excessive internal pressure is generated by the gas generated inside the battery, the battery is not separated by the gas pressure or gas harmful to the human body is prevented from leaking out of the battery, and the electrolyte can be prevented from leaking out of the battery.

Here, the insulator 170 may be made of a PBT (polybutylene terephthalate) material. In the case of PBT material, mechanical properties are good, and in particular, due to high rigidity, a battery with excellent airtightness and durability can be realized.

The button-type secondary battery 100 according to Embodiment 1 of the present invention may include a first electrode tab 154 extending from the first electrode 151 of the electrode assembly 150 . The first electrode tab 154 may extend from the first electrode 151 of the electrode assembly 150 to be in contact with the upper can 130 . In this case, the first electrode 151 may be a positive electrode, and the first electrode tab 154 may be a positive electrode tab. In this case, the first electrode tab 154 may extend from the positive electrode of the electrode assembly 150 to be in contact with the upper can 130 .

In the button-type secondary battery 100 according to the first embodiment of the present invention, the upper can 130 may include an upper can electrode terminal part 133 . The upper can electrode terminal part 133 may be a part that is connected through the first electrode 151 and the first electrode tab 154 of the electrode assembly 150 to form a terminal (particularly a positive electrode terminal) connected to an external device. . In particular, the upper can electrode terminal part 133 may be a portion covering the upper opening of the lower can 110 .

In this case, the first electrode tab 154 may include a contact portion 154a in contact with the upper can electrode terminal portion 133 . Specifically, the first electrode tab 154 may include a support portion 154b and a contact portion 154a. The support portion 154b may be a portion connected to the plurality of first electrodes 151 of the electrode assembly. When the first electrode is the positive electrode, the support part 154b may be connected to the positive electrode. Connection may mean that the support part 154b is adhered to the first electrode (anode) or that the support part 154b and the first electrode (anode) are integrally formed.

In the button-type secondary battery 100 according to Embodiment 1 of the present invention, the support 154b may be connected to the first electrode 151 of the electrode assembly 150. In this case, the support 154b and the lower can 110 are There may be a risk of a short-circuit accident. To prevent this, the inner insulator 171 may be positioned between the first electrode tab 154 and the lower can 110 to prevent the first electrode tab 154 from contacting the lower can 110 . In FIG. 3 , it can be seen that the support part 154b and the upper end of the lower can 110 do not meet each other because the inner insulator 171 is interposed therebetween.

Meanwhile, the contact portion 154a connected to the support portion 154b may extend from the support portion 154b and contact the upper can electrode terminal portion 133 . Specifically, the upper surface of the contact portion 154a may be in contact with the lower surface of the upper can 130 . In this case, the entire upper surface of the contact portion 154a may be in contact with the lower surface of the upper can 130 . Through this contact, current may flow between the first electrode tab 154 and the upper can 130 .

FIG. 3 shows only the electrode assembly 150 and the first electrode tab 154 in the button-type secondary battery 100 according to the first embodiment of the present invention. Referring to FIG. 3 , the support part 154b may be formed in a bar shape. What is desired here may mean various rod shapes. That is, it may be in the shape of a thin rod in the form of a cylinder, and in addition to that, it may be in the shape of a rod in the form of a quadrangular pole, or in the shape of a rod in the form of a triangular prism. And the contact portion 154a may be formed in a circular ring shape. The circular ring shape may mean the overall shape of the contact part 154a. That is, the cross-sectional shape of the circular ring may not necessarily be a circle, and may have various shapes such as a square or a triangle. However, the cross section is extended along the closed curve to form a circular ring shape as a whole. In addition, the upper surface of the circular annular contact portion 154a may be a portion in contact with the upper can 130 . In particular, the contact portion 154a may contact the upper can electrode terminal portion 133 .

The meaning that the contact portion 154a is in contact with the upper can 130 means that the contact portion 154a and the upper can 130 are not adhered to each other. It could just mean being touched. That is, when the upper can 130 rotates, the upper can 130 and the contact portion 154a only move relative to each other while in contact with each other, and the rotation of the upper can 130 does not act to rotate the contact portion 154a. It may mean not

Conventionally, in general, a battery is manufactured by bonding the first electrode tab 154 to the upper can electrode terminal part 133 through welding. That is, the first electrode tab 154 was adhered to the upper can 130 . However, in this method, when the upper can 130 is rotated to screw the upper can 130 and the lower can 110 together, the first electrode tab 154 is twisted and breaks.

However, in the button-type secondary battery 100 according to the first embodiment of the present invention, such a problem does not occur. In the present invention, since the first electrode tab 154 only contacts the upper can 130 , even if the upper can 130 is rotated, the first electrode tab 154 may not rotate in place.

In addition, in the button-type secondary battery 100 according to the first embodiment of the present invention, the contact area with the upper can 130 may be increased by forming the contact portion 154a in a circular ring shape. As a result, resistance is reduced, enabling smooth current flow.

Also, as a method of further increasing the contact area, there may be a method of increasing the thickness of the contact portion 154a having a circular ring shape. Here, the thickness may be expressed as the difference between the inner diameter and the outer diameter of the circular ring. As an example of thickening the contact portion 154a, the thickness of the contact portion 154a may be greater than that of the support portion 154b.

Moreover, in the present invention, the outer peripheral diameter of the contact portion 154a formed in a circular ring shape and the outer peripheral diameter of the electrode assembly 150 may have a corresponding size. In this case, since it means that the diameter of the contact portion 154a becomes as large as possible, a battery having the lowest resistance can be manufactured with the same thickness.

In addition to this, in order to reduce the size of the resistance, the shape of the contact portion 154a may be implemented in another form. Specifically, the support portion 154b may be formed in a bar shape, and the contact portion 154a may be formed in a disk shape. If it is formed in the shape of a disk, it can make surface contact with the upper can, increasing the contact area and making the resistance smaller.

Specifically, in the button-type secondary battery according to Embodiment 1 of the present invention, the electrode assembly 150 may include a first electrode 151 , a separator 153 , and a second electrode 152 . A plurality of first electrodes 151 , a separator 153 , and a second electrode 152 may be horizontally stacked.

2 and 4 , the first electrode 151 extends laterally from the first electrode holding part 151a in which the electrode active material is applied to the electrode current collector, and the first electrode holding part 151a, and is an electrode. The first electrode uncoated region 151b made of only an electrode current collector without being coated with an active material may be included. The first electrode holding part 151a may be in the form of a thin disk having a circular shape in a plan view.

The first electrode uncoated region 151b may have a rectangular shape and extend to the side of the first electrode holding part 151a. The first electrode uncoated region 151b may be an electrode current collector extending therefrom.

In the same manner, the second electrode 152 extends laterally from the second electrode holding part 152a in which the electrode active material is applied to the electrode current collector, and the second electrode holding part 152a, and the electrode active material is not applied thereto. A second electrode uncoated region 152b made of only an electrode current collector may be included. The second electrode holding part 152a may be in the form of a thin disk having a circular shape in a plan view.

The second electrode uncoated region 152b may have a rectangular shape and extend to the side of the second electrode holding part 152a. The second electrode uncoated region 152b may be an electrode current collector extending therefrom.

In the button-type secondary battery according to the first embodiment of the present invention, the support portion 154b of the first electrode tab 154 may be connected to the plurality of first electrode uncoated portions 151b.

In particular, as shown in FIG. 2 , the plurality of first electrode uncoated regions 151b may be bonded to each other to form a first electrode uncoated region bundle 151c, where the support portion 154b is the first electrode uncoated region. It may be in the form of being connected to the bundle 151c.

As the button-type secondary battery according to Embodiment 1 of the present invention is manufactured in such a shape, it is possible to maximize the battery capacity and energy density by improving the volume ratio occupied by the electrode assembly 150 in the battery.

Specifically, in the prior art, the electrode assembly 150 inside the battery was a jelly roll type electrode assembly 150 manufactured by winding an electrode and a separator. A central hall was formed. Accordingly, a space that does not produce electricity is formed in the center of the electrode assembly 150 .

In contrast, the present invention can maximize the battery capacity and energy density because such a wasted space such as a central hall can be eliminated.

And, in the electrode assembly 150 of the button-type secondary battery according to Embodiment 1 of the present invention, the separator 153 may be a safety reinforced separator (SRS) single-sided coated separator. The SRS separator may mean that the surface of the separator 153 is thinly coated with a ceramic material. In the case of using the SRS single-sided coated separator, a thinner separator 153 may be used, and thus more electrodes may be stacked, thereby securing more increased battery capacity.

And, in the button-type secondary battery according to the first embodiment of the present invention, the plurality of first electrodes 151 , the separator 153 , and the second electrode 152 have a circular shape and are horizontally stacked, and the entire stack is It may be joined up and down by heat and pressure. That is, the laminate may exist in the form of one unit by adhesion. In this case, since the first electrode 151 and the second electrode 152 do not move relative to each other, a short circuit can be prevented, and an effect that the electrode assembly 150 can be stably maintained can be obtained.

And in the button type secondary battery according to Embodiment 1 of the present invention, another electrode tab of the electrode assembly 150 is the second electrode tab 156 , and the second electrode tab 156 is to be connected to the second electrode 152 . can The second electrode 152 also includes a second electrode holding portion 152a and a second electrode uncoated region 152b, and the second electrode tab 156 may be connected to the plurality of second electrode uncoated regions 152b. .

In addition, the method of connecting the second electrode tab 156 to the lower can 110 may be by welding. Since the second electrode tab 156 connected to the lower can 110 is not rotated by screw coupling, it may not be a problem even if it is connected to the lower can 110 by welding. That is, unlike when the first electrode tab 154 is connected to the upper can 130 by a contact method, the second electrode tab 156 may be connected to the upper can 130 by a bonding method.

Example 2

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

In Embodiment 2 of the present invention, the difference from Embodiment 1 is that the end 231 of the upper can is formed differently and the outermost first electrode 251-1 is in contact with the upper can 130 . there may be

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. 5 , in the button-type secondary battery 200 according to the second embodiment of the present invention, the end 231 of the upper can may be bent in the central axis direction of the lower can 110 . When the end 231 of the upper can is bent in this way, the coupling force between the upper can 130 and the lower can 110 can be significantly improved. In the method of manufacturing the button-type secondary battery 200 according to the second embodiment of the present invention, the upper can 130 that is not bent is first rotated to be screwed to the lower can 110, and after the screwing is completed, the upper can 130 is rotated. It may be a method of bending the end 231 of the can in the central axis direction of the lower can 110 .

5 shows that the end 273a of the outer insulator is longer than the end 231 of the upper can and extends downward. That is, the outer insulator 273 may extend downward along the outer wall of the lower can 110 , but the end 273a of the outer insulator may be longer than the end 231 of the upper can and extend downward. Through this, the short-circuit prevention effect of the upper can 130 and the lower can 110 can be enhanced.

In addition, the end 273a of the outer insulator may extend long enough to cover the lower edge of the lower can so as to touch the bottom of the lower can. When the end 273a of the outer insulator extends longer in this way, the short-circuit prevention effect of the upper can 130 and the lower can 110 may be further increased.

In addition, the surface that contacts the outer insulator 273 from the end 231 of the upper can may be a flat surface. Accordingly, it is possible to prevent the end 231 of the upper can from damaging the outer insulator 273 . If the end 231 of the upper can is not flat and has a protruding shape, the end 231 of the upper can is pressed and bent, and in the process of touching the outer insulator 273, the contacting surface of the outer insulator 273 may be cut or drilled. can However, in the present invention, since the tip 231 of the upper can is flat, this problem can be prevented from occurring.

And, as shown in FIG. 5 , in the button-type secondary battery 200 according to the second embodiment of the present invention, the outermost first electrode 251-1 disposed on the outermost side of the electrode assembly 150 is a first electrode tab. (254) may be in contact with the lower surface. That is, the upper surface of the outermost first electrode 251-1 may be in contact with the lower surface of the first electrode tab 254 . In particular, the upper surface of the outermost first electrode 251-1 may be in contact with the lower surface of the contact portion 254a of the first electrode tab 254 . Here, since the outermost first electrode 251-1 and the contact portion 254a have the same polarity, contact with each other may not be a problem. In this way, when the outermost first electrode 251-1 and the first electrode tab 254 are formed to be in contact with each other, space efficiency may be further improved. That is, the energy density may be further improved. And if the contact area is increased, the resistance may be reduced. And since it is possible to completely prevent the electrode assembly 150 from shaking inside the battery, it is possible to realize a more stable button-type secondary battery 200 .

In addition, the first electrode uncoated area bundle 251c in which the first electrode uncoated areas are gathered may also be formed to contact the first electrode tab 254 . Also, as shown in FIG. 5 , the first electrode uncoated region bundle 251c may be formed to be in contact with the lower surface of the contact portion 254a. This structure can also further improve the energy density.

And, in the button-type secondary battery 200 according to the second embodiment of the present invention, the outermost first electrode 251-1 is not coated with an electrode active material on the outer side facing the upper can, and only the inner side is coated with an electrode active material. It may be a single-sided electrode with

Since the upper surface of the outermost first electrode 251-1 does not have a second electrode corresponding to each other, it becomes a portion that does not react even if an electrode active material is present. Therefore, if the non-reactive electrode active material is removed, that is, if the outermost first electrode 251-1 is configured as a single-sided electrode, the energy density may be further improved. This is because the waste of space in the non-responsive part can be prevented. In addition, since waste of the electrode active material can be prevented, production cost can be reduced. In addition, when the electrode current collector and the upper can directly contact, the effect of reducing the resistance can be obtained.

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: button type secondary battery
110: lower can
111: first thread
130: upper can
131: the end of the upper can
132: second thread
133: upper can electrode terminal part
150: electrode assembly
151: first electrode
151a: first electrode holding part
151b: first electrode uncoated region
151c: first electrode uncoated region bundle
152: second electrode
152a: second electrode holding part
152b: second electrode uncoated region
153: separator
154: first electrode tab
154a: contact
154b: support
156: second electrode tab
170: insulator
171: inner insulator
172: connection insulator
173: outer insulator
173a: the end of the outer insulator
200: button type secondary battery
231: the end of the upper can
251-1: outermost first electrode
251c: first electrode uncoated region bundle
254a: contact
254b: support
273: outer insulator
273a: the end of the outer insulator

Claims (19)

In a button-type secondary battery in which the length of the diameter is greater than the height,
electrode assembly;
a lower can in which the electrode assembly is inserted and a first screw thread is formed on an outer circumferential surface;
an upper can covering an upper opening of the lower can and having a second screw thread corresponding to the first screw thread formed on an inner circumferential surface; and
an insulator interposed between the upper can and the lower can to prevent a short circuit between the upper can and the lower can;
The electrode assembly is formed by horizontally stacking a plurality of first electrodes, a separator, and a second electrode,
A button-type secondary battery in which a first electrode tab extending by being connected to the first electrode of the electrode assembly is in contact with the upper can. The method according to claim 1,
The upper can is
and an upper can electrode terminal part connected to the first electrode of the electrode assembly through the first electrode tab to form a terminal connected to an external device, and covering an upper opening of the lower can;
The first electrode tab,
a support part connected to the plurality of first electrodes of the electrode assembly; and
and a contact portion extending from the support portion and contacting the upper can electrode terminal portion. 3. The method according to claim 2,
The first electrode is
a first electrode holding member in which an electrode active material is applied to an electrode current collector; and
and a first electrode uncoated portion extending laterally from the first electrode holding portion and comprising only the electrode current collector without an electrode active material applied thereto;
The support part is a button type secondary battery, characterized in that connected to the plurality of first electrode uncoated parts. 4. The method according to claim 3,
The plurality of first electrode uncoated regions are bonded to each other to form a first electrode uncoated region bundle,
The support part is a button type secondary battery, characterized in that connected to the first electrode uncoated part bundle.
3. The method according to claim 2,
The support part is formed in a bar shape,
The contact portion is a button type secondary battery, characterized in that formed in a circular ring shape. 6. The method of claim 5,
A button-type secondary battery, characterized in that the thickness of the contact portion having a circular ring shape is thicker than the thickness of the support portion. 3. The method according to claim 2,
The support part is formed in a bar shape,
The button-type secondary battery, characterized in that the contact portion is formed in the shape of a disk. 6. The method of claim 5,
A button type secondary battery, characterized in that the outer peripheral diameter of the contact portion formed in a circular ring shape and the outer peripheral diameter of the electrode assembly have sizes corresponding to each other. The method according to claim 1,
The insulator is a button type secondary battery, characterized in that the PBT (polybutylene terephthalate) material. The method according to claim 1,
The insulator is
an inner insulator positioned inside the lower can;
an outer insulator positioned outside the lower can; and
A button-type secondary battery comprising a connection insulator connecting the inner insulator and the outer insulator. 11. The method of claim 10,
The upper can and the lower can are screwed by the first screw thread and the second screw thread,
the outer insulator is interposed between the first thread and the second thread;
The outer insulator is pressed by the protrusion shape of the first screw thread and the second screw thread to have a concave-convex shape and is sandwiched between the first screw thread and the second screw thread. 11. The method of claim 10,
The inner insulator is positioned between the first electrode tab and the lower can to prevent contact between the first electrode tab and the lower can. The method according to claim 1,
The separator is a button-shaped secondary battery, characterized in that the SRS (safety reinforced separator) single-sided coated separator. The method according to claim 1,
The plurality of first electrodes, separators, and second electrodes have a circular shape and are horizontally stacked, and the entire stack is vertically joined by heat and pressure. The method according to claim 1,
The button type secondary battery, characterized in that the outermost first electrode disposed on the outermost side of the electrode assembly is in contact with the lower surface of the first electrode tab. 3. The method according to claim 2,
The button type secondary battery, characterized in that the outermost first electrode disposed on the outermost side of the electrode assembly is in contact with the lower surface of the contact part. 17. The method according to claim 15 or 16,
The outermost first electrode is a button-shaped secondary battery, characterized in that the outer side facing the upper can is not coated with the electrode active material, only the inner side of the electrode active material is a single-sided electrode is coated. The method according to claim 1,
The button-type secondary battery, characterized in that the end of the upper can is bent in the central axis direction of the lower can. 11. The method of claim 10,
The outer insulator extends downward along the outer wall of the lower can,
A button-type secondary battery, characterized in that the end of the outer insulator is longer than the end of the upper can and extends downward.

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