KR102637937B1 - Secondary battery and method for manufacturing the battery - Google Patents

Abstract

The present invention relates to a secondary battery, and more specifically, to a secondary battery including a housing cup, a housing cover, an insulating member, and an electrode assembly, wherein the housing cup and the housing cover are insulated from each other by the insulating member, and The electrode assembly is a wound electrode assembly in which the central axis of the electrode assembly is stored in the bottom of the housing cup and the bottom of the housing cover in a vertical direction, and the electrode assembly is electrically connected to the uncoated portion of the first electrode plate of the electrode assembly. and a first electrode tab connected to and drawn out, wherein an end region of the first electrode tab is welded and in contact with an inner surface of a side wall portion of the housing cover, and a method of manufacturing the same.

Description

Secondary battery and method of manufacturing the same {SECONDARY BATTERY AND METHOD FOR MANUFACTURING THE BATTERY}

The present invention relates to secondary batteries, and more specifically, to button-type secondary batteries and their manufacturing methods.

In general, button-type secondary batteries are small and thin, so when miniaturization is required to be used as a power source for small electronic devices such as wristwatches and hearing aids, or when thinness is required to be used as a power source for thin electronic devices such as IC cards, etc. It is widely used, etc.

Since button-type secondary batteries require a small size, there are limits to improving battery capacity, and it is important to minimize unnecessary space inside the battery. Accordingly, recent attempts to improve the capacity of button-type secondary batteries by using wound-type electrode assemblies are continuing.

In a button-type secondary battery using a wound electrode assembly, the electrode tab drawn out from the electrode is in direct contact with the housing, and the housing itself serves as an electrode terminal. At this time, if the electrode tab and the housing are not completely adhered, the electrode There is a problem of disconnection between the tab and the housing.

Therefore, in order to strengthen the adhesion between the electrode tab and the housing of the button-type secondary battery, methods of bonding the electrode tab and the housing by welding have been proposed. For example, after storing the electrode assembly in the housing cover, there is a method of welding and adhering the flat surface of the housing cover and the electrode tab from the inside through the hollow part of the electrode assembly.

However, even in this case, the electrode tab of the electrode opposite to the electrode bonded by welding is already blocked by the housing cover in the hollow part of the electrode assembly, and there is a problem in that direct welding is difficult due to the side wall existing in the housing cup. Accordingly, after completely assembling the housing cup, there is a method of welding the flat surface of the housing cup and the electrode tab of the opposite electrode from the outside of the housing cup. In this case, the housing cup, which is a welding base material, and the electrode of the opposite electrode are used. Since it is difficult to secure sufficient adhesion between tabs, welding quality deteriorates, and as a result, there is a problem that the welded portion may be disconnected due to external impact, etc.

J.P. 2002-164076 A

The problem to be solved by the present invention is to solve the problems mentioned in the background technology of the above invention, in a secondary battery using a wound electrode assembly, especially a button-type secondary battery, by attaching the electrode tab to the housing cup or housing cover. When welding, welding quality is improved by securing adhesion between welding base materials compared to external welding, and furthermore, the stability and capacity of the battery are simultaneously secured from the structure of the secondary battery.

In other words, the present invention was developed to solve the problems of the prior art, and the welding quality between the electrode tab and the housing is improved, and the unnecessary space inside the battery is minimized to ensure both stability and capacity, and the manufacture thereof. The purpose is to provide a method.

According to one embodiment of the present invention for solving the above problem, the present invention relates to a secondary battery including a housing cup, a housing cover, an insulating member, and an electrode assembly, wherein the housing cup and the housing cover are connected to the insulating member. are insulated from each other, and the electrode assembly is a wound electrode assembly in which the central axis of the electrode assembly is stored in the vertical direction at the bottom of the housing cup and the bottom of the housing cover, and the electrode assembly is a first electrode of the electrode assembly. A secondary battery is provided, comprising a first electrode tab electrically connected to and drawn out from an uncoated portion of the plate, wherein an end region of the first electrode tab is welded and in contact with an inner surface of a side wall portion of the housing cover.

In addition, the present invention includes the steps of welding the end region of the first electrode tab drawn out by being electrically connected to the uncoated portion of the first electrode plate of the wound electrode assembly to the inner surface of the side wall portion of the housing cover; Storing the wound electrode assembly in the bottom of the housing cover so that the central axis of the electrode assembly is vertical; providing an insulating member to cover a side wall of the housing cover; Provided is a secondary battery manufacturing method including the step of inserting the housing cover provided with the insulating member into a housing cup.

In the case of a secondary battery according to the present invention, especially a button-type secondary battery including a wound electrode assembly, the electrode tab is welded directly to the housing cup or housing cover before assembling the housing cup and housing cover, so that the electrode tab is welded directly to the housing cup or housing cover after assembling the housing. Compared to the welding method, the adhesion between welding base materials increases, which has the effect of improving welding quality. Furthermore, by adopting a structure of electrode tabs with bends to enable this welding method, the stability of the battery is improved and space utilization within the housing is maximized, which has the effect of securing both battery stability and capacity through this secondary battery structure. There is.

1 is a perspective view and a plan view of a secondary battery according to an embodiment of the present invention.
Figure 2 is a cross-sectional view (Z-Z') of a secondary battery according to an embodiment of the present invention.
Figure 3 is a perspective view and a top view of a secondary battery according to an embodiment of the present invention.
Figure 4 is a cross-sectional view (Y-Y') of a secondary battery according to an embodiment of the present invention.
Figure 5 is a schematic diagram of a process for manufacturing a secondary battery according to an embodiment of the present invention.

Terms or words used in the description and claims of the present invention should not be construed as limited to their ordinary or dictionary meanings, and the inventor should appropriately use the concept of the term to explain his or her invention in the best way. Based on the principle of definability, it must be interpreted with meaning and concept consistent with the technical idea of the present invention.

Hereinafter, with reference to the drawings, a secondary battery and its manufacturing method according to an embodiment of the present invention will be described in more detail.

As shown in Figures 1 and 2, the secondary battery 10 according to the present invention includes a housing cup 100, a housing cover 200, an insulating member 300, and an electrode assembly 400, and the housing cup (100) and the housing cover 200 are insulated from each other by the insulating member 300, and the electrode assembly 400 is connected to the bottom 110 of the housing cup 100 and the housing cover 200. It is a wound electrode assembly in which the central axis 430 of the electrode assembly 400 is stored in the vertical direction on the bottom 210, and the electrode assembly 400 is electrically connected to the uncoated portion of the first electrode plate of the electrode assembly. and a first electrode tab 410 that is drawn out, and an end region 414 of the first electrode tab 410 may be welded and in contact with the inner surface of the side wall portion 220 of the housing cover 200. there is.

A secondary battery 10 according to an embodiment of the present invention will be described with reference to FIGS. 2 and 5 . In the secondary battery 10, the diameter L1 of the bottom 110 of the housing cup 100 may be larger than the length L2 in the height direction of the side wall 120 of the housing cup 100. That is, the secondary battery may satisfy L1>L2. A secondary battery having this housing size may refer to a so-called button-type secondary battery.

According to one embodiment of the present invention, the housing cup 100 includes a bottom portion 110, a side wall portion 120, a corner portion 130 between the bottom portion and the side wall portion, an end region 140 of the side wall portion, and an opening portion. It may include. The entire housing cup 100 may function as one electrode terminal. Additionally, the housing cup 100 may have a cup shape.

Meanwhile, although not shown in the drawing, the secondary battery according to an embodiment of the present invention further exposes all or part of the bottom portion 110 of the housing cup to the outside and further includes an insulating material such as a seal tape surrounding the outer surface of the housing cup. It can be included. In this case, the portion of the housing cup exposed to the outside actually functions as an external electrode terminal.

According to one embodiment of the present invention, the bottom portion 110 and the side wall portion 120 of the housing cup 100 may exist in a perpendicular state to each other, and the side wall portion 120 may have a cylindrical shape. The corner portion 130 between the bottom portion 110 and the side wall portion 120 may have the shape of a bent portion with sharp corners or a bent portion with rounded corners.

In addition, the end area 140 of the side wall 120 of the housing cup 100 is a part of the side wall 120, and when necessary, when manufacturing a secondary battery, the housing cover 200 is specifically used as a housing cup ( After insertion into 100), it may be bent to cover the corner portion 230 of the housing cover 200. Specifically, the end area 140 of the side wall 120 of the housing cup 100 refers to an area that has been bent to cover the corner 230 of the housing cover 200. You can. By bending the end area 140 of the housing cup 100 to face inward, not only can the housing cover 200 and the housing cup 100 be more firmly and stably fixed and coupled, but also the housing cup 100 Sealing performance can also be improved by the insulating member 300 interposed between the and housing cover 200.

Meanwhile, the bottom portion 110 of the housing cup 100 is a part that constitutes the lowermost surface of the housing cup 100 and refers to a portion located inside the corner portion 130 of the lowermost surface. The bottom 110 of the housing cup 100 may have a disk shape, for example. Meanwhile, in the final state of the secondary battery after assembly of the housing cup 100 and the housing cover 200, the bottom 110 of the housing cup 100 is divided into the bottom 210 of the housing cover 200, which will be described later. It may be parallel and at the same time perpendicular to the side wall portion 120 of the housing cup 100 and the side wall portion 220 of the housing cover 200.

In addition, according to one embodiment of the present invention, the housing cover 200 may include a bottom 210, a side wall 220, a corner 230 between the bottom and the side wall, and an opening. . The entire housing cover 200 may serve as one electrode terminal, and specifically may serve as an electrode terminal opposite to that of the housing cup 100. Additionally, the housing cover 200 may have a cup shape.

According to one embodiment of the present invention, the bottom portion 210 and the side wall portion 220 of the housing cover 200 may exist in a perpendicular state to each other, and the side wall portion 220 may have a cylindrical shape. The corner portion 230 between the bottom portion 210 and the side wall portion 220 may have the shape of a bent portion with sharp corners or a bent portion with rounded corners.

According to one embodiment of the present invention, the housing cup 100 and the housing cover 200 are formed according to the electrode polarity of the electrode tabs 410 and 420 bonded to the housing cup 100 and the housing cover 200, respectively. Electrodes can be determined.

As a specific example, when the first electrode tab 410 is a negative electrode tab and the second electrode tab 420 is a positive electrode tab, the housing cup 100 is a negative terminal housing, and the housing cover 200 is a positive terminal housing. can be, when the first electrode tab 410 is a positive electrode tab and the second electrode tab 420 is a negative electrode tab, the housing cup 100 is a positive terminal housing, and the housing cover 200 is a negative terminal housing. You can.

According to one embodiment of the present invention, the material of the housing cup 100 and the housing cover 200 may be nickel-plated steel, stainless steel, or aluminum, and as a specific example, the housing cup 100 and Depending on the electrode properties of the electrode tabs 410 and 420 respectively bonded to the housing cover 200, the housing cup 100 or housing cover 200 to which the negative electrode tab is bonded is made of nickel-plated steel, stainless steel, or aluminum. may be, and the housing cup 100 or the housing cover 200 to which the anode tab is attached may be a nickel-plated steel plate or stainless steel.

According to one embodiment of the present invention, the nickel-plated steel sheet may be a nickel-plated cold-rolled steel sheet (SPCC, Steel Plate Cold Commercial). Additionally, the stainless steel may be iron-chromium-based ferritic stainless steel, iron-nickel-chromium-based austenitic stainless steel, or a mixture thereof. Additionally, the aluminum may be aluminum itself or an alloy containing aluminum.

According to one embodiment of the present invention, the bottom 110 of the housing cup 100 and the bottom 210 of the housing cover 200 may be parallel to each other, and the bottom of the housing cup 100 The distance between the portion 110 and the bottom 210 of the housing cover 200 (or the thickness between the bottom portions) is determined by the insulation member 300 accommodated by the housing cup 100 and the housing cover 200. and the electrode assembly 400.

In addition, according to one embodiment of the present invention, the housing cover 200 has an outer surface of the side wall portion 220 of the housing cover 200 facing the inner surface of the side wall portion 120 of the housing cup 100. It may be inserted into the housing cup 100 so that an overlapping area exists. Furthermore, in the overlapping area, the side wall portion 120 of the housing cup 100 and the side wall portion 220 of the housing cover 200 can be maintained in an insulated state with the insulating member 300 interposed therebetween.

Specifically, the housing cover 200 is such that an end in the direction of the opening formed by the side wall portion 220 of the housing cover 200 is positioned in the direction of the bottom 110 of the housing cup 100. It may be inserted into the opening of the housing cover 200, and the end in the direction of the opening formed by the side wall portion 220 of the housing cover 200 is connected to the bottom portion 110 of the housing cup 100 and the insulating member 300. It may be in insulated contact with an intervening layer.

In addition, according to one embodiment of the present invention, the insulating member 300 includes a first insulating member (not shown) including only the bottom portion 310, a side wall portion 320, and a space between the bottom portion and the side wall portion. It may include a second insulating member (not shown) including the corner portion 330 and the end region 340 of the side wall portion, or the bottom portion 310, the side wall portion 320, and between the bottom portion and the side wall portion. It may be an integrated insulating member 300 including a corner portion 330 and an end region 340 of a side wall portion. In terms of battery stability, it may be desirable to use an integrated insulating member 300.

According to one embodiment of the present invention, the housing cup 100 and the housing cover 200 may be insulated from each other by the insulating member 300. Here, the insulating member 300 may be an insulation gasket for sealing and insulating the housing cup 100 and the housing cover 200.

As a specific example, the side wall portion 320 of the insulating member 300 may be located between the outer surface of the side wall portion 220 of the housing cover 200 and the inner surface of the side wall portion 120 of the housing cup 100. You can.

As a more specific example, the side wall portion 120 of the housing cup 100 and the side wall portion 220 of the housing cover 200 may be sealed and insulated by the side wall portion 320 of the insulating member 300. and an end in the direction of the opening formed by the bottom 110 of the housing cup 100 and the side wall 220 of the housing cover 200 is formed by the bottom 310 of the insulating member 300. Can be sealed and insulated.

According to one embodiment of the present invention, the bottom portion 310 of the insulating member 300 is located between the lower portion of the electrode assembly 400 and the inner surface of the bottom portion 310 of the housing cup 100. You can.

Specifically, the inner surface of the bottom portion 110 of the housing cup 100 and the lower portion of the electrode assembly 400 may be insulated from each other by the insulating member 300. This has the effect of preventing a short circuit between the second electrode tab 420 welded or glued to the housing cup 100 and the first electrode, such as the first electrode plate in the electrode assembly 400.

According to one embodiment of the present invention, the end area 340 of the side wall portion 320 of the insulating member 300 is a part of the side wall portion 320 and is a part of the corner portion 230 of the housing cover 200. It may be located between the outer surface and the inner surface of the end region 140 of the housing cup 100. For example, when manufacturing a secondary battery, specifically, after inserting the housing cover 200 into the housing cup 100, the end region 140 of the side wall portion 120 of the housing cup 100 is bent. By bending the end area 340 of the side wall 320 of the insulating member 300, the end area 340 of the side wall 320 of the insulating member 300 is formed into the housing cover 200. ) can be made to cover the corner portion 230.

According to one embodiment of the present invention, the material of the insulating member 300 may be polyolefin-based resin, polyester-based resin, or polyether-based resin. The polyolefin-based resin may be polyethylene-based resin (PE) or polypropylene-based resin (PP). Additionally, the polyester-based resin may be polybutylene terephthalate resin (PBT). Additionally, the polyether-based resin may be polyether ether ketone resin (PEEK).

In addition, according to one embodiment of the present invention, the bottom 310 of the insulating member 300 is connected to the bottom 110 of the housing cup 100 and the bottom 210 of the housing cover 200. It may be parallel. The bottom 310 of the insulating member 300 has a first pattern (not shown) for drawing the second electrode tab 420 from the electrode assembly 400 through the bottom 310 of the insulating member 300. ) and a second pattern (not shown) formed to the same size as the hollow portion existing in the direction of the central axis 430 of the electrode assembly 400.

At this time, the first pattern and the second pattern may each be a hole formed in the bottom 310 of the insulating member 300, and the shape of the hole is circular, oval, or kidney bean. It may be oval.

In addition, according to one embodiment of the present invention, the bottom portion 310 of the insulating member 300 has a step difference by a thickness for positioning the second electrode tab with respect to the corner portion 330 of the insulating member 300. It can be formed with .

At this time, the step may be a thickness between the outer surface (lower surface) of the bottom 310 of the insulating member 300 and the inner surface (upper surface) of the bottom 110 of the housing cup 100. Specifically, the thickness between the outer surface (lower surface) of the bottom 310 of the insulating member 300 and the inner surface (upper surface) of the bottom 110 of the housing cup 100 is the second electrode tab 420. ) may be 1 to 2 times, 1 to 1.5 times, or 1 to 1.2 times the thickness of. Due to the above step range, the second electrode tab 420 is accommodated within this range, and the outer surface (lower surface) of the bottom 310 of the insulating member 300, the second electrode tab 420, and the housing cup ( The inner surface (upper surface) of the bottom part 110 of 100 can be in close contact with no empty space. Through this, there is no gap in the space within the secondary battery housing, especially the lower space, which has the effect of improving the stability of the battery by preventing disconnection and short circuit even under vibration and impact.

According to one embodiment of the present invention, the electrode assembly 400 has a central axis 430 of the electrode assembly in a vertical direction to the bottom 110 of the housing cup and the bottom 210 of the housing cover 200. It may be a wound electrode assembly that is stored in a.

Specifically, the electrode assembly 400 may be an electrode assembly in the form of a jelly-roll in which a first electrode plate, a separator, and a second electrode plate are sequentially stacked and wound from the central axis 430 of the electrode assembly. and the stacked structure of the first electrode plate, separator, and second electrode plate is (1) first electrode plate/separator/second electrode plate/separator, (2) first electrode plate/separator/second electrode plate/ A separator may be placed between the first electrode plate and the second electrode plate, such as separator/first electrode plate, (3) second electrode plate/separator/first electrode plate/separator/second electrode plate, etc.

According to one embodiment of the present invention, the first electrode plate of the electrode assembly 400 may be a positive electrode plate or a negative electrode plate, and the second electrode plate may be a negative electrode plate or a positive electrode plate. Specifically, the first electrode plate may be a negative electrode plate. may be, and the second electrode plate may be a positive electrode plate.

In addition, according to one embodiment of the present invention, the electrode assembly 400 may have a wound first electrode plate forming the outermost shell of the electrode assembly 400, and in this case, the first electrode tab 410 Since the housing cover 200, which is welded and serves as a negative electrode terminal, and the outermost electrode of the electrode assembly located in the vertical direction of the central axis 430 of the electrode assembly 400 have the same electrode, the housing cover 200 and Even if the electrode assemblies 400 come into contact with each other, they do not short-circuit, and accordingly, a separate insulating member such as a separator of the electrode assembly 400 is not required between the inner surface of the housing cover 200 and the electrode assembly 400, thereby forming a secondary battery. It has the effect of minimizing the internal space of the.

According to one embodiment of the present invention, the electrode assembly 400 may include a first electrode tab 410 that is electrically connected to and drawn out from the uncoated portion 401 of the first electrode plate of the electrode assembly 400. there is. Specifically, the uncoated portion 401 of the first electrode plate may be provided on the outermost side of the wound first electrode plate, and more specifically, the first electrode tab 410 may be provided in the electrode assembly 400. It may be pulled out from the uncoated portion 401 provided on the outermost side of the wound first electrode plate.

For convenience of illustration, the uncoated portion 401 provided at the outermost portion of the first electrode plate is located in the vertical direction of the central axis 430 of the electrode assembly 400, as shown in FIGS. 2 and 4. Although shown at the top, the uncoated portion 401 is a portion that exists in a direction parallel to the central axis 430 of the electrode assembly 400 among the outermost portions of the first electrode plate of the electrode assembly 400. You can. The first electrode tab 410 may be electrically connected to and drawn out from an uncoated portion existing at an arbitrary position among the uncoated portions 401 .

In this case, as will be described later, for reasons of ease of process for direct welding of the first electrode tab 410 and the housing cover 200, the length of the first electrode tab 410 is shortened to the side wall portion of the housing cover 200. It needs to be equal to or longer than the length in the height direction of (220). When the first electrode tab 410 is pulled out from the uncoated portion 401 provided on the outermost side of the first electrode plate, the first electrode tab 410 is removed in the process of inserting the electrode assembly 400 into the housing cover 200. The number of times 410 is bent and overlapped can be minimized. That is, in order to minimize the increase in thickness due to overlapping of the first electrode tabs 410 and further minimize the internal space of the secondary battery, it is preferable that the first electrode tabs are drawn from the uncoated portion 401 provided on the outermost side. do.

Meanwhile, the first electrode tab 410 of the electrode assembly 400 is not the uncoated portion 401 provided on the outermost side of the wound first electrode plate, but the upper part of the electrode assembly 400, that is, the electrode assembly 400. ) can also be pulled out from any position on the upper part of the electrode assembly 400 located in the vertical direction of the central axis 430.

Additionally, according to one embodiment of the present invention, the first electrode tab 410 may be the uncoated portion itself of the first electrode plate of the electrode assembly 400, or the first electrode tab ( 410) may be pulled out while being adhered to the uncoated portion of the first electrode plate of the electrode assembly 400.

According to one embodiment of the present invention, the total length of the first electrode tab 410 may be equal to or longer than the length in the height direction of the side wall portion 220 of the housing cover 200.

According to one embodiment of the present invention, the first electrode tab 410 may be welded and adhered to the inner surface of the side wall portion 220 of the housing cover 200. In this case, the first electrode tab 410 If the length is smaller than the height direction length of the side wall portion 220 of the housing cover 200, it is difficult to bring the first electrode tab 410 into close contact with the side wall portion 220 of the housing cover 200, resulting in welding. There is a problem that cannot be implemented.

Therefore, it is preferable that the length of the first electrode tab 410 is equal to or longer than the length in the height direction of the side wall portion 220 of the housing cover 200, and specifically, the length of the first electrode tab 410 may be 1 to 5 times, 1 to 3 times, or 1 to 2 times the length of the side wall 220 of the housing cover 200 in the height direction, and within this range, the first electrode tab 410 ), while minimizing the increase in the internal space of the secondary battery, improving welding quality by securing adhesion between welding base materials compared to external welding, and securing the stability of the secondary battery.

Additionally, according to an embodiment of the present invention, the first electrode tab 410 may include a first bent portion 411 and a second bent portion 412, and the second bent portion 412 The first electrode tabs 410 that are bent and face each other may be in surface contact 413. The first bent portion 411 and the second bent portion 412 of the first electrode tab 410 are used to cover the electrode assembly 400 with a housing after welding the first electrode tab 410 when manufacturing a secondary battery. (200) It may be formed by bending the first electrode tab 410 when stored.

In addition, according to an embodiment of the present invention, the surfaces of the first electrode tabs 410 that are bent by the second bent portion 412 and face each other may be in surface contact 413 with each other, and accordingly, the surfaces of the first electrode tabs 410 may be in surface contact 413 with each other. While minimizing the increase in the internal space of the secondary battery due to the electrode tab 410, the gap in the empty space within the secondary battery can be minimized or eliminated, thereby preventing vibration, shock, etc. that may be applied from the outside when using the secondary battery. It is effective in ensuring the stability of secondary batteries.

In addition, according to one embodiment of the present invention, the surface contact 413 is bent by the second bent portion 412 to cover 50% to 100% or 80% of the surface of the first electrode tab 410 facing each other. This may mean that from 100% to 100%, or from 90% to 100%, they are in contact with each other.

In addition, according to one embodiment of the present invention, the first electrode tab 410 is welded to the inner surface of the side wall portion 220 of the housing cover 200 with an end region 414 of the first electrode tab 410. It may be adhesive, and in this case, there is an effect of securing adhesion between the housing cover 200 and the first electrode tab 410.

According to one embodiment of the present invention, the end region 414 of the first electrode tab 410 is bent by the second bent portion 412 and is in contact with the side wall portion 220 of the housing cover 200. It may mean, and specifically, the end area 414 of the first electrode tab 410 may mean an area welded and adhered to the side wall part 220 of the housing cover 200.

In addition, according to one embodiment of the present invention, the surface that is bent by the second bent portion 412 and faces each other is in surface contact 413, and is in contact with the first electrode tab 410. Among the surfaces, that is, a portion of the first electrode tab 410 located between the first bent part 411 and the second bent part 412, the surface in the direction toward the bottom 210 of the housing cover 200 is the insulating surface. It may be in close contact with the bottom portion 310 of the member 300. In this case, the space between the bottom 310 of the insulating member 300, the first electrode tab 410, and the bottom 110 of the housing cup 100 is minimized, thereby ensuring the stability of the secondary battery. There is.

According to one embodiment of the present invention, between the outermost outer surface of the electrode assembly located in the vertical direction of the central axis 430 of the electrode assembly 400 and the inner surface of the side wall portion 220 of the housing cover 200 The thickness may be 1.5 to 2.3 times, 1.7 to 2.1 times, or 1.9 to 2.0 times the thickness of the first electrode tab 410. According to the above thickness range, when the first electrode tab 410 that is bent by the second bent portion 412 and makes surface contact 413 is accommodated, the vertical axis of the central axis 430 of the electrode assembly 400 The outermost surface of the electrode assembly located in this direction and the inner surface of the side wall portion 220 of the housing cover 200 may be in close contact with each other without any empty space. Through this, there is no gap in the space within the secondary battery housing, especially the side space, which has the effect of improving the stability of the battery by preventing disconnection and short circuit even under vibration and impact.

Meanwhile, the thickness between the outermost outer surface of the electrode assembly located in the vertical direction of the central axis 430 of the electrode assembly 400 and the inner surface of the side wall portion 220 of the housing cover 200 is the electrode assembly ( Thickness when the first electrode tab 410 is located between the outermost outer surface of the electrode assembly located in the vertical direction of the central axis 430 of the 400) and the inner surface of the side wall portion 220 of the housing cover 200 It may represent the outermost outer surface of the electrode assembly located in the vertical direction of the central axis 430 of the electrode assembly 400 where the first electrode tab 410 is not located and the side wall portion of the housing cover 200 ( The inner surfaces of the electrodes 220) are in contact with each other without any empty space, or the maximum separation distance is the outermost outer surface of the electrode assembly located in the vertical direction of the central axis 430 of the electrode assembly 400 and the side wall of the housing cover 200. The thickness of the inner surface of the portion 220 may be spaced apart from the thickness of the first electrode tab 410 .

In addition, according to an embodiment of the present invention, the thickness of the first electrode tab 410 is 10 It may be ㎛ to 150 ㎛, 40 ㎛ to 120 ㎛, or 60 ㎛ to 100 ㎛, and within this range, while minimizing the increase in the internal space of the secondary battery due to the first electrode tab 410, when adhering by welding, Sufficient adhesion can be secured, which has the effect of securing the stability of the secondary battery.

According to one embodiment of the present invention, the electrode assembly 400 may include a second electrode tab 420 that is electrically connected to and drawn out from the uncoated portion 402 of the second electrode plate of the electrode assembly 400. there is. Specifically, the uncoated portion 402 of the second electrode plate may be provided on the outermost side of the wound second electrode plate, and more specifically, the second electrode tab 420 may be provided in the electrode assembly 400. It may be pulled out from the uncoated portion 402 provided on the outermost side of the wound second electrode plate.

For convenience of illustration, the uncoated portion 402 provided at the outermost portion of the second electrode plate is located in the vertical direction of the central axis 430 of the electrode assembly 400, as shown in FIGS. 2 and 4. Although shown at the bottom, the uncoated region 402 is a portion that exists in a direction parallel to the central axis 430 of the electrode assembly 400 among the outermost portions of the second electrode plate of the electrode assembly 400. You can. The second electrode tab 420 may be electrically connected to and drawn out from an uncoated portion existing at an arbitrary position among the uncoated portions 402 . At this time, the second electrode plate from which the second electrode tab 420 is pulled out may be an electrode plate opposite to the first electrode plate from which the first electrode tab 410 is pulled out.

Meanwhile, the second electrode tab 420 of the electrode assembly 400 is not drawn from the uncoated portion 402 provided on the outermost side of the wound second electrode plate, but also from any position below the electrode assembly 400. However, in order to minimize the internal space of the secondary battery, it is preferable that it is drawn out from the uncoated region 402 provided on the outermost side of the second electrode plate.

Additionally, according to one embodiment of the present invention, the second electrode tab 420 may be a non-coated portion of the second electrode plate of the electrode assembly 400 that is directly drawn out, or the second electrode tab 420 This may be pulled out while being adhered to the uncoated portion of the second electrode plate of the electrode assembly 400.

In addition, according to one embodiment of the present invention, the end area 424 of the second electrode tab 420 is adhered to the inner surface of the bottom 110 of the housing cup 100. It may have happened. Specifically, the end area 424 of the second electrode tab 420 may be welded and adhered to the inner surface of the bottom 110 of the housing cup 100. In this case, there is an effect of securing adhesion between the housing cover 200 and the second electrode tab 420, and accordingly, the first electrode tab 410 and the second electrode tab 420 are each connected to the housing cover. Since it is attached in a welded state to (200) and the housing cup 100, disconnection between the electrode tab and the housing is prevented, and the stability of the secondary battery is improved.

According to one embodiment of the present invention, the electrode assembly 400 may include a center pin (not shown) in the hollow portion of the central axis 430. The center pin is stored in the hollow portion of the central axis 430 of the electrode assembly 400 to minimize or eliminate the gap in the empty space within the secondary battery, thereby preventing the gap that may be applied from the outside when using the secondary battery. It is effective in ensuring the stability of the secondary battery against vibration, shock, etc.

According to one embodiment of the present invention, the center pin may have a cylindrical shape, and the height of the center pin in a horizontal direction with the central axis 430 of the electrode assembly 400 is determined by the material bonded to the housing cup 100. 1 It may be equal to the distance between the electrode tab 410 and the inner surface of the bottom 210 of the housing cover 200, and the thickness of the center pin in a direction perpendicular to the central axis 430 of the electrode assembly 400 ( or diameter) may be equal to the thickness (or diameter) of the hollow portion of the central axis 430 of the electrode assembly 400.

According to one embodiment of the present invention, the center pin may be an insulating resin, and specifically may be a polyolefin-based resin, polyester-based resin, or polyether-based resin. The polyolefin-based resin may be polyethylene-based resin (PE) or polypropylene-based resin (PP). Additionally, the polyester-based resin may be polybutylene terephthalate resin (PBT). Additionally, the polyether-based resin may be polyether ether ketone resin (PEEK).

In addition, as shown in FIGS. 3 and 4, the bottom portion 210 of the housing cover 200 of the secondary battery 20 according to another embodiment of the present invention is provided with a step portion 2110 that provides a height step. It may have a surface height of 2 or more. That is, the bottom portion 210 of the housing cover 200 may be protruded so that the central portion is higher than the peripheral portion. Meanwhile, the inner diameter from the center portion to the step portion 2110 is the end area of the side wall portion 320 of the insulating member 300 that covers the corner portion 230 of the housing cover 200 and exists in a bent shape. It may be smaller than the inner diameter of (340).

According to one embodiment of the present invention, the secondary battery may be one in which an electrolyte solution is injected into the housing cup 100, the housing cover 200, and the insulating member 300 along with the electrode assembly 400.

In addition, according to an embodiment of the present invention, the secondary battery further includes an insulating member (not shown) to prevent short circuit between the top of the electrode assembly 400 and the bottom 210 of the housing cover 200. can do.

Additionally, the present invention provides a manufacturing method for manufacturing the secondary battery.

As shown in Figure 5, the secondary battery manufacturing method according to the present invention is an end region of the first electrode tab 410 that is electrically connected to the uncoated portion of the first electrode plate of the wound electrode assembly 400 and drawn out ( Step (a) of welding 414) to the inner surface of the side wall portion 220 of the housing cover 200; Step (b) storing the wound electrode assembly 400 in the bottom 210 of the housing cover 200 so that the central axis 430 of the electrode assembly 400 is vertical; Step (c) of providing an insulating member 300 to cover the side wall portion 220 of the housing cover 200; It may include step (d) of inserting the housing cover 200 provided with the insulating member 300 into the housing cup 100.

According to one embodiment of the present invention, the end area 414 of the first electrode tab 410 that is electrically connected to the uncoated portion of the first electrode plate of the wound electrode assembly 400 and drawn out is formed into a housing cover 200. ), the step (a, hereinafter referred to as step (a)) of welding the inner surface of the side wall portion 220 is welding and adhering the first electrode tab 410 to the side wall portion 220 of the housing cover 220. As a step for this, through step (a), the first electrode tab 410 may be welded and adhered to the housing cover 200.

According to one embodiment of the present invention, the welding may be performed by laser welding or resistance welding. Specifically, the first electrode tab 410 may be welded to the inner surface of the side wall 220 of the housing cover 200. When laser welding is performed, the side wall 220 of the housing cover 200 It is possible to sufficiently bring the first electrode tab 410, which is the welding base material, and the side wall portion 220 of the housing cover 200 into close contact by using a back-up jig on the outer surface, thereby improving welding quality. This has the effect of preventing disconnection of the weld zone.

In addition, since the housing cover 200 according to the present invention is the outermost member of the secondary battery, it is easy to apply mechanical pressure between the first electrode tab 410 and the side wall portion 220 of the housing cover 200, thereby reducing resistance. It can be welded by welding, the welding quality is improved, and this has the effect of preventing disconnection of the weld zone.

According to one embodiment of the present invention, storing the wound electrode assembly 400 in the bottom 210 of the housing cover 200 so that the central axis 430 of the electrode assembly 400 is in the vertical direction. (b, hereinafter referred to as step (b)) is a step for accommodating the electrode assembly 400 in the housing cover 200, wherein the electrode assembly 400 is welded and adhered to the side wall portion 220 of the housing cover 200. 1 The electrode tab 410 may be bent in advance before being stored, or may be bent at the same time as being stored.

According to one embodiment of the present invention, the electrode assembly 400 is configured to prevent short circuit between the top of the electrode assembly 400 and the bottom 210 of the housing cover 200. An insulating member (not shown) may be further included on the upper part of the electrode assembly 400 in a direction perpendicular to the central axis 430.

According to one embodiment of the present invention, the step (c, hereinafter referred to as step (c)) of providing the insulating member 300 to cover the side wall portion 220 of the housing cover 200 includes the electrode assembly 400. A step of providing the insulating member 300 to the temporarily accommodated housing cover 200, wherein the end of the side wall portion 220 of the housing cover 200 in the direction of the opening is the inner surface of the bottom portion 310 of the insulating member 300. It can be carried out by inserting it into contact with.

According to one embodiment of the present invention, the insulating member 300 is formed by attaching a second electrode tab 420 from the electrode assembly 400 to the bottom 310 of the insulating member 300. A first pattern (not shown) for drawing out through the bottom portion 310, and a second pattern (not shown) formed to the same size as the hollow portion existing in the direction of the central axis 430 of the electrode assembly 400. It may include one, and the second electrode tab 420 of the electrode assembly 400 may be inserted into the externally drawn state through the first pattern.

According to one embodiment of the present invention, the step (d, hereinafter referred to as step (d)) of inserting the housing cover 200 provided with the insulating member 300 into the housing cup 100 is performed by inserting the housing cover 200 with the insulating member 300 into the housing cup 100. ), a step of inserting the housing cover 200 in which the electrode assembly 400 is stored and the insulating member 300 provided therein, wherein the bottom 110 of the housing cup 100 is connected to the second electrode tab ( 420), the side wall portion 120 of the housing cup 100 is in complete contact with the side wall portion 320 of the insulating member 300, and the corner portion 130 of the housing cup 100 is in complete contact with the side wall portion 320 of the insulating member 300. , It can be implemented by inserting it into complete contact with the corner portion 330 of the insulating member 300.

In addition, according to an embodiment of the present invention, in step (d), the housing cover 200 provided with the insulating member 300 is inserted into the housing cup 100, and then the housing cup 100 and A step of bending the end area 140 of the housing cup 100 to cover the edge 230 of the housing cover 200 so that the housing cover 200 can be completely sealed. can do.

Specifically, in step (d), the end region 140 of the side wall portion 120 of the housing cup 100 and the end region 340 of the side wall portion 320 of the insulating member 300 are The end area 140 of the side wall 120 of the housing cup 100 and the end area of the side wall 320 of the insulating member 300 are formed to cover the edge 230 of the housing cover 200 ( 340) may include bending at the same time.

In addition, according to an embodiment of the present invention, the secondary battery manufacturing method is performed after step (b) or step (c), that is, by inserting the housing cover 200 into the housing cup 100 to manufacture the secondary battery. Before sealing, it may include the step of injecting an electrolyte solution.

10, 20: Secondary battery
100: housing cup
110: Bottom of housing cup
120: Side wall portion of housing cup
130: Edge between the bottom and side wall of the housing cup
140: End area of the side wall portion of the housing cup
200: Housing cover
210: Bottom of housing cover
211: Bend portion of the bottom of the housing cover
220: Side wall portion of housing cover
230: Corner between the bottom and side wall of the housing cover
300: insulation member
310: Bottom portion of insulating member
320: Side wall portion of insulating member
330: Edge between the bottom and side wall of the insulating member
340: End area of the side wall portion of the insulating member
400: Electrode assembly
401: Uncoated portion of the first electrode plate
402: Uncoated portion of the second electrode plate
410: first electrode tab
411: first bent portion of the first electrode tab
412: second bent portion of the first electrode tab
413: Surface contact area of the first electrode tab
414: End area of the first electrode tab
420: second electrode tab
424: End area of second electrode tab
430: Central axis of electrode assembly
L1: Diameter of the bottom of the housing cup
L2: Length in the height direction of the side wall of the housing cup
L3: Thickness between the outermost surface of the electrode assembly located in the direction perpendicular to the central axis of the electrode assembly and the inner surface of the side wall of the housing cover

Claims (10)

In a secondary battery including a housing cup, a housing cover, an insulating member, and an electrode assembly,
The housing cup and the housing cover are insulated from each other by the insulating member,
The electrode assembly is a wound electrode assembly in which the central axis of the electrode assembly is stored in a vertical direction in the bottom of the housing cup and the bottom of the housing cover,
The electrode assembly includes a first electrode tab drawn out and electrically connected to an uncoated portion of the first electrode plate of the electrode assembly,
The end area of the first electrode tab is welded and contacted to the inner surface of the side wall of the housing cover,
The first electrode tab includes a first bent portion and a second bent portion, and the first electrode tabs that are bent by the second bent portion and face each other are in surface contact. According to paragraph 1,
The secondary battery is a secondary battery in which the diameter of the bottom of the housing cup is larger than the length of the side wall of the housing cup in the height direction. According to paragraph 1,
A secondary battery wherein an end area of the housing cup is bent to cover a corner of the housing cover. According to paragraph 1,
A secondary battery wherein the inner surface of the bottom of the housing cup and the lower part of the electrode assembly located in a direction perpendicular to the central axis of the electrode assembly are insulated from each other by the insulating member. According to paragraph 1,
The uncoated portion of the first electrode plate is provided at the outermost portion of the wound first electrode plate of the electrode assembly,
A secondary battery wherein the outermost portion of the electrode assembly located in a direction perpendicular to the central axis of the electrode assembly is the first electrode plate. According to paragraph 1,
A secondary battery wherein the thickness between the outer surface of the outermost electrode located in a direction perpendicular to the central axis of the electrode assembly and the inner surface of the side wall portion of the housing cover is 1.5 to 2.3 times the thickness of the first electrode tab. According to paragraph 1,
The thickness of the first electrode tab is 10 Secondary battery of ㎛ to 150 ㎛. According to paragraph 1,
The electrode assembly includes a second electrode tab drawn out and electrically connected to an uncoated portion of the second electrode plate of the electrode assembly,
A secondary battery wherein an end area of the second electrode tab is in contact with the bottom of the housing cup. Welding the end region of the drawn-out first electrode tab electrically connected to the uncoated portion of the first electrode plate of the wound electrode assembly to the inner surface of the side wall portion of the housing cover;
Storing the wound electrode assembly in the bottom of the housing cover so that the central axis of the electrode assembly is vertical;
providing an insulating member to cover a side wall of the housing cover;
The secondary battery manufacturing method of claim 1, comprising inserting the housing cover provided with the insulating member into a housing cup. According to clause 9,
The secondary battery manufacturing method includes the step of inserting the housing cover provided with the insulating member into the housing cup and then bending the end area of the housing cup to cover the corner of the housing cover. Manufacturing method.