KR20170110821A - Battery Cell Comprising Cylindrical Can Having Screw-typed Fastening Portion - Google Patents

Abstract

The present invention relates to a battery cell in which a top assembly including a jelly-roll having a positive electrode / separator / negative electrode structure, a safety member and a connecting member is housed in a cylindrical can, An upper can having a first fastening portion formed at a lower end portion of the first body; And a lower can having a second body having the jelly-roll built therein and a second fastening part formed at an upper end of the second body, wherein the first fastening part and the second fastening part have a screw ) Method of the present invention is a threaded structure.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a battery cell including a cylindrical can which is fastened by a screw method,

The present invention relates to a battery cell including a cylindrical can which is fastened by a screw method.

As technology development and demand for mobile devices has increased, the demand for secondary batteries has been rapidly increasing as an energy source. Many researches have been made on lithium secondary batteries with high energy density and discharge voltage among such secondary batteries. .

When a secondary battery is used as a power source for a mobile phone or a notebook computer, a secondary battery that stably supplies a constant output is required. On the other hand, when the secondary battery is used as a power source for a power tool such as an electric drill, A secondary battery which can be stable against an external physical impact such as dropping, etc. is required.

The secondary battery is classified into a cylindrical battery and a prismatic battery in which the electrode assembly is housed in a cylindrical or rectangular metal can according to the shape of the battery case, and a pouch-shaped battery in which the electrode assembly is housed in a pouch-shaped case of an aluminum laminate sheet . Among them, the cylindrical battery has a relatively large capacity and is structurally stable against external physical impact, and the pouch type battery has an advantage in that it is small in weight in weight, easy to deform in shape, and low in manufacturing cost have.

In addition, the electrode assembly incorporated in the battery case is a chargeable / dischargeable power generation device formed of a lamination structure of a positive electrode / separator / negative electrode. The electrode assembly is a jelly-roll type electrode assembly in which a separator is interposed between a positive electrode and a negative electrode coated with an active material, And a stacked type in which a plurality of positive electrodes and negative electrodes of a predetermined size are sequentially stacked with a separator interposed therebetween. Among them, the jelly-roll type electrode assembly has an advantage of being easy to manufacture and having a high energy density per weight.

In this regard, the structure of a typical cylindrical secondary cell is shown in FIG.

1, a cylindrical rechargeable battery 100 includes a jelly-roll type (wound type) electrode assembly 120 having a structure in which an anode 121, a cathode 122, and a separator 123 are sequentially stacked and wound in a round shape, Is formed in the battery case 130 and the electrolyte solution is injected into the battery case 130 and then the cap assembly 140 having the electrode terminals formed at the open upper end of the battery case 130 is assembled. To attach the cap assembly 140, a beading portion (see arrow) is formed on the upper portion of the battery case 130, and the upper portion is crimped and sealed with the gasket and the cap assembly 140 mounted thereon.

However, the above beading and crimping require a complicated manufacturing process, and in particular, the metal pieces generated in the beading process flow into the battery case 130 and cause serious problems such as a short circuit.

In addition, since the conventional cylindrical battery has the gas discharging portion formed on the upper portion of the battery case, when the gas is discharged through the discharging port due to high temperature and high pressure inside the battery, the battery is moved in the other direction in the gas discharging direction do. This causes serious safety problems for users of devices using the battery as a power source.

Therefore, there is a high need for a battery cell capable of solving the problems described above.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

Specifically, the object of the present invention is to provide a battery cell capable of achieving the following special effect by interlocking the upper and lower cans in a screw manner, and preferably forming a soft portion at a specific position of the fastening portion .

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, a battery cell includes a cylindrical can having a top assembly including a positive electrode / separator / negative structure jelly-

The cylindrical can includes:

An upper can having a first body having a top assembly mounted thereon and a first fastening part formed at a lower end of the first body; And

A lower can having a second body having the jelly-roll built therein and a second fastening part formed at an upper end of the second body;

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The first fastening portion and the second fastening portion are formed in a threaded structure that is fastened together by a screw method.

As described above, the battery cell according to the present invention can be manufactured by a simple and simple process without requiring complicated manufacturing processes such as beading and clamping by combining the upper and lower cans in a screw manner. In addition, when the battery cell is activated and the gas generated inside the battery cell is to be removed, the inner can be easily removed by separating the upper and lower can by the screw method.

The jelly-roll is not particularly limited, but may be circular in vertical section, and the combined structure of the upper can and the lower can may have an inner surface structure corresponding to the outer shape of the jelly-roll.

In one specific example, in the jelly-roll, one side end of the positive electrode current collector and one side end of the negative electrode current collector, to which the electrode active material is not coated, extend outward from the separator to form the positive electrode terminal and the negative electrode terminal. .

In this structure, at least one of the one end portion of the positive electrode current collector forming the positive electrode terminal and the one end portion of the negative electrode current collector forming the negative electrode terminal may be partially overlapped in the wound jelly-roll . By forming the positive and negative terminals of the jelly-roll in this manner, by adjusting the length of engagement between the first fastening portion and the second fastening portion, which will be described later in detail, the electrode terminals are physically brought into close contact with the inner surface of the cap assembly or the battery case So that a good connection can be achieved.

The size of the overlapped portion may be determined in consideration of ease of physical contact with the inner surface of the battery case or the cap assembly, mechanical rigidity of the battery assembly, and the like, and more specifically, 20% to 80% And 20% to 100% of the width of the electrode terminal.

In one specific example, the positive terminal of the jelly-roll is physically brought into close contact with the bottom surface of the top assembly, and the top assembly is physically contacted with the inner surface of the first body to provide electrical connection, The coupling length between the first and second coupling portions may be adjusted during the coupling process. Likewise, in order to electrically connect the negative terminal of the jelly-roll to the inner surface of the lower can to electrically connect the upper can and the lower can, the coupling length between the first and second fasteners is adjusted Lt; / RTI >

The coupling length of the first and second fastening portions may be determined in consideration of ease of physical contact with the cap assembly of the jelly-roll electrode terminal or the inner surface of the battery case, mechanical rigidity thereof, and the like, May range from 5% to 40% of the length of the can. If the bonding length is less than 5%, adjustment of the bonding length is not easy. If it exceeds 40%, the lengths of the upper and lower can must be longer than necessary before the bonding process. not. From this viewpoint, it is more preferable that the length of the first fastening portion is 10% to 30% of the length of the upper can, and the length of the second fastening portion is 10% to 30% of the length of the lower can.

As an example, the first fastening portion may have a structure in which a screw thread is formed on the outer surface of the lower end of the upper can or the inner surface of the lower end of the upper can, and the first fastening portion The second fastening portion may be coupled to the upper can inner surface or the upper end outer surface of the lower can correspondingly to the threaded structure of the fastening portion.

A gasket may further be interposed between the first fastening portion and the second fastening portion to prevent leakage of the electrolyte and gas. Since the gasket may include an insulating function, the upper can is the anode of the battery cell and the lower can is the cathode.

In one specific example, the first fastening portion and the second fastening portion may be formed with soft portions such that the first fastening portions and the second fastening portions can be ruptured by the high pressure inside the battery cell. The soft portions may be formed at an intermediate portion with respect to the longitudinal direction of the cylindrical can coupled with the upper and lower can. In particular, the soft portions may be symmetrical with respect to the center of the circle formed in the vertical section in the circumferential direction at the intermediate portion.

As one example, one soft portion may be formed at two intersections where a straight line passing through the center of the circle and a circle circumference of the circle meet each other. As another example, when all the vertexes of a regular polygon (for example, a regular triangle, a square, or the like) are placed on the circumference of the circle, one soft portion may be formed at each intersection. With this configuration, the force of the gas ejected from the weak portions cancel each other out, so that the battery cell does not move in any specific direction. At this time, the soft portion is not particularly limited, but may be a notch.

The present invention also provides a battery pack including at least one battery cell. Here, the electric cell may be, for example, a capacitor or a secondary battery.

Further, the present invention provides a device including the battery pack as a power source. The device may be a notebook computer, a netbook, a tablet PC, a mobile phone, an MP3 player, a wearable electronic device, a power tool, an electric vehicle EV, a hybrid electric vehicle (HEV) , A plug-in hybrid electric vehicle (PHEV), an electric bike (E-bike), an electric scooter (E-scooter), an electric golf cart, However, the present invention is not limited thereto.

The specific configuration of the capacitor, the secondary battery, and the device is well known in the art, and a description thereof will be omitted herein.

As described above, the battery cell according to the present invention can simplify the manufacturing process by fastening the upper and lower cans in a screw manner, and in one specific example, the soft portions are formed at specific positions of the fastening portions The thrust force due to the gas ejection can be canceled each other to improve the safety, and since the electrode terminals of the jelly-roll are partially overlapped, excellent electrical connection can be achieved inside the battery case without welding.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a vertical cross section along a longitudinal direction of a cylindrical battery cell according to the prior art; FIG.
FIG. 2 is a schematic view showing a vertical section of a battery cell according to an embodiment of the present invention, in a longitudinal direction; FIG.
Figure 3 is an exploded view of the cylindrical can of Figure 2;
FIG. 4 is a schematic view showing that the fastening portions of FIG. 2 are formed with soft portions;
5 is a cross-sectional schematic diagram showing that the soft portions of FIG. 4 are positioned symmetrically with respect to one another;
Fig. 6 is a schematic view showing that electrode terminals of the jelly-roll of Fig. 2 are partially overlapped. Fig.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

FIG. 2 is a schematic vertical sectional view of a battery cell according to an embodiment of the present invention, and FIG. 3 is an exploded view of the cylindrical can of FIG.

2 and 3, the battery cell 200 includes a jelly-roll 220 having a positive electrode / separator / negative electrode structure, a top assembly Y including a safety member and a connection member, As shown in FIG.

The cylindrical can 210 includes an upper can 211 having a first body 212 on which the top assembly Y is mounted and a first fastening portion 213 formed on the lower end of the first body 212, And a lower can 214 having a second body 215 in which the jelly-roll 220 is embedded and a second coupling part 216 formed in the upper end of the second body 215, The first fastening part 213 and the second fastening part 216 have a threaded structure that is fastened together by a screw method.

The combined structure of the upper can 211 and the lower can 214 has an inner surface structure corresponding to the outer shape of the jelly-roll 220.

The positive terminal 221 of the jelly-roll 220 is physically brought into close contact with the bottom surface of the top assembly and the top assembly Y is physically brought into close contact with the inner surface of the first main body 212, The coupling length of the first coupling part 213 and the second coupling part 216 is adjusted in the process of coupling the upper and lower can 211 and 214. Similarly, in order to electrically connect the cathode terminal 222 of the jelly-roll 220 to the inner surface of the lower can 214, the upper can 211 and the lower can 214 The coupling length of the first coupling part 213 and the second coupling part 216 is adjusted.

The combined length L of the first fastening portion 213 and the second fastening portion 216 is 5% to 40% of the length H of the combined cylindrical can 210. The length h1 of the first fastening part 213 is 10% to 30% of the length H1 of the upper can 211. Similarly, the length h2 of the second fastening portion 216 is 10% to 30% of the length H2 of the lower can 214.

The first fastening part 213 has a structure in which a thread is formed on the inner surface of the lower end of the upper can 211. The second fastening part 216 corresponds to the threaded structure of the first fastening part 213, And a screw thread is formed on the upper surface of the upper end of the upper surface 214. A gasket (not shown) including an insulating function is interposed between the first fastening portion 213 and the second fastening portion 216. [

FIG. 4 is a schematic view showing that the fastening portions of FIG. 2 are formed with the soft portions, and FIG. 5 is a cross-sectional view showing that the soft portions of FIG. 4 are positioned symmetrically with respect to each other.

Referring to FIGS. 3, 4, and 5, the first fastening portion 213 and the second fastening portion 216 may be separated from each other by a high pressure in the battery cell 200, And the second fastening portion 216 are formed with two or more fragile portions 230. The soft portions 230 are formed in the intermediate region A with respect to the longitudinal direction of the cylindrical can 210 to which the upper and lower can 211 and 214 are coupled. Specifically, the center of the circle 280 formed in the vertical section in the circumferential direction in the intermediate region A is symmetrical with respect to the notched soft portions 230. In the embodiment (i) of FIG. 5, the soft portions 230 are located on a straight line passing through the center of the circle 280. In the embodiment (ii) of FIG. 5, the soft portions 230 are formed at the intersections of the square vertices and the circle 280. With these structures, even if the high-temperature / high-pressure gas inside the battery cell 200 is ejected (C) through the soft portions, the thrusts C due to the ejections C cancel each other, It will not move in this specific direction.

Fig. 6 is a schematic view showing that electrode terminals of the jelly-roll of Fig. 2 are partially overlapped. Fig.

2, 3 and 6, the jelly-roll 220 is circular in vertical section, and has one end of a current collector for a positive electrode and a current collector for a negative electrode, And extends outward from the separator to form a cathode terminal 221 and an anode terminal 222. [ One side end of the negative electrode current collector forming the positive electrode terminal 221 and one end of the negative electrode current collector forming the negative electrode terminal 222 are partly overlapped in the wound jelly roll 220 . The sizes I and II of the overlapped portions of the positive electrode terminals 221 are 20% to 80% of the projected length M of the positive electrode terminals 221 and 20% to 20% of the width D of the positive electrode terminals 221 100%.

When the electrode terminals 221 and 222 are partly overlapped and the electrode terminals 221 and 222 are assembled together in the structure in which the upper and lower can 211 and 214 are fastened together, Since the surface physically contacting the inside of the base plate 214 is widened, good connection can be achieved without any additional welding.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention.

Claims (20)

A battery cell in which a top assembly including a jelly-roll having a positive electrode / separator / negative electrode structure, a safety member, and a connection member is embedded in a cylindrical can,
The cylindrical can includes:
An upper can having a first body having a top assembly mounted thereon and a first fastening part formed at a lower end of the first body; And
A lower can having a second body in which the jelly-roll is embedded and a second fastening part formed in an upper end of the second body;
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Wherein the first fastening part and the second fastening part are threaded structures that are mutually fastened by a screw method. The battery cell according to claim 1, wherein the jelly-roll is circular in vertical section. The battery cell according to claim 1, wherein the combined structure of the upper can and the lower can has an inner surface structure corresponding to an outer shape of the jelly-roll. The jelly-roll according to claim 1, wherein one end of the current collector for the positive electrode and one end of the current collector for the negative electrode, from which the electrode active material is not coated, extend outward from the separator to form the positive electrode terminal and the negative electrode terminal A battery cell characterized by: The positive electrode current collector according to claim 4, wherein at least one of the one end of the positive electrode current collector and the negative electrode current collector forming the negative electrode terminal is partially overlapped in the wound jelly-roll . The battery cell according to claim 5, wherein the size of the overlapping portion is 20% to 80% of the protruding length of the electrode terminal. The battery cell according to claim 5, wherein the size of the overlapping portion is 20% to 100% of the width of the electrode terminal. The method of claim 1, wherein the jelly roll is physically brought into close contact with the bottom surface of the top assembly, and the top assembly is physically contacted with the inner surface of the first body to establish electrical connection, Wherein the coupling length of the first fastening part and the second fastening part is adjusted in the coupling process. 2. The method of claim 1, wherein the joint of the first and second fasteners in the process of joining the upper and lower can, so that the cathode terminal of the jelly-roll is physically brought into close contact with the inner surface of the lower can, Is adjusted. The battery cell according to claim 8 or 9, wherein the coupling length of the first fastening part and the second fastening part is 5% to 40% of the length of the cylindrical can. The battery cell according to claim 1, wherein a length of the first fastening portion is 10% to 30% of a length of the upper can. The battery cell according to claim 1, wherein a length of the second fastening portion is 10% to 30% of a length of the lower can. [2] The apparatus according to claim 1, wherein the first fastening part has a structure in which a screw thread is formed on the lower end outer surface or the lower end inner surface of the upper can, and the second fastening part corresponds to the threaded structure of the first fastening part, And a line is formed on an upper surface of the battery cell. The battery cell according to claim 1, wherein a gasket is interposed between the first fastening portion and the second fastening portion. The battery cell according to claim 1, wherein the first fastening portion and the second fastening portion are formed with soft portions so that the first fastening portion and the second fastening portion can be ruptured by the high pressure inside the battery cell. 16. The battery cell according to claim 15, wherein the soft portions are formed at an intermediate portion of the cylindrical can coupled with the upper and lower can. 17. The battery cell according to claim 16, wherein the soft portions are symmetrical with respect to a center of a circle formed in a vertical section in the circumferential direction at the intermediate portion. 18. The battery cell according to any one of claims 15 to 17, wherein the soft portion is a notch. A battery pack comprising at least one battery cell according to claim 1. A device comprising the battery pack according to claim 19 as a power source.

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