CN116636059A - Secondary battery and device including the same - Google Patents

Abstract

The secondary battery according to an embodiment of the present disclosure includes: an electrode assembly; a battery case accommodating the electrode assembly; and a concave portion that is concave from the bottom of the battery case in a direction toward the inside of the battery case, wherein a gas discharge port is formed in the concave portion.

Description

Secondary battery and device including the same

Technical Field

Cross Reference to Related Applications

The present application claims the benefits of korean patent application No.10-2021-0109148, filed on 8 months 19 of 2021, and korean patent application No.10-2022-0101288, filed on 12 months 8 of 2022, the contents of both of which are incorporated herein by reference.

The present disclosure relates to a secondary battery and an apparatus including the same, and more particularly, to a secondary battery having improved long-term life and an apparatus including the same.

Background

Recently, demand for portable electronic products such as notebook computers, video cameras, cellular phones, etc. is rapidly increasing, and electric vehicles, energy storage batteries, robots, satellites, etc. are actively developing. Accordingly, many studies have been made on a secondary battery used as a driving power source thereof.

The secondary batteries are classified into: a cylindrical battery in which an electrode assembly is built in a cylindrical metal can; a prismatic battery in which an electrode assembly is built in a prismatic metal can; and a pouch-type battery in which the electrode assembly is built in a pouch-type case formed of an aluminum laminate sheet. Among these batteries, the cylindrical battery has an advantage in that it has a relatively large capacity and is structurally stable.

The electrode assembly built in the battery case is a power generation device having a cathode/separator/anode laminate structure capable of charging and discharging, and is classified into a winding type, a stacking type, and a stacking/folding type. The winding type has the following shape: the cathode and the anode, each made of a long sheet coated with an active material, are wound with a separator interposed therebetween, and the stack has the following shape: a plurality of cathodes and a plurality of anodes each having a predetermined size are sequentially laminated in a state in which a separator is interposed between the cathodes and the anodes, and the stack/fold type is a combination of a winding type and a stack type. Among these types, the rolled electrode assembly has advantages of easy manufacture and high energy density per unit weight.

Meanwhile, the secondary battery includes, for example, a nickel-cadmium battery, a nickel-hydrogen battery, a nickel-zinc battery, a lithium secondary battery, and the like. Among these secondary batteries, since the lithium secondary battery has the following advantages: for example, a lithium secondary battery shows little memory effect compared to a nickel-based secondary battery, thus being freely charged and discharged, and has a very low self-discharge rate, a high operating voltage, and a high energy density per unit weight, and thus is widely used in the field of high-tech electronic devices.

At this time, after the electrode assembly is received in the battery case to constitute the secondary battery, the secondary battery undergoes an activation process that is placed at a high temperature and is charged/discharged a plurality of times, and a large amount of gas is generated inside the secondary battery through the above-described process. At this time, in the case of the pouch-type battery, the gas may be discharged through a degassing process that discharges the gas generated after the activation process, but the conventional cylindrical battery does not have a degassing process, which makes it impossible to discharge the internal gas.

Therefore, the conventional cylindrical battery does not immediately discharge the gas generated through the activation process to the outside, which causes a problem of a reduction in the long-term life of the battery.

Therefore, there is a need for a novel structure that is capable of performing a degassing process of a cylindrical battery, and thus allowing internal gas to be discharged to the outside, and has an effect of improving a long-term life.

Disclosure of Invention

Technical problem

It is an object of the present disclosure to provide a secondary battery having improved long-term life and an apparatus including the same.

However, the technical problems to be solved by the embodiments of the present disclosure are not limited to the above-described problems, and various extensions can be made within the scope of the technical ideas included in the present disclosure.

Technical proposal

According to an aspect of the present disclosure, there is provided a secondary battery including: an electrode assembly; a battery case accommodating the electrode assembly; and a concave portion that is concave from the bottom of the battery case in a direction toward the inside of the battery case, wherein a gas discharge port is formed in the concave portion.

The secondary battery includes an electrode tab connected to an electrode assembly, wherein a recess is formed at the bottom of the battery case where the electrode tab is not formed.

The secondary battery may further include a cover portion covering the gas discharge port.

The cover is rotatable.

A gas discharge port hole is formed in the gas discharge port, and a cover hole is formed in the cover.

The cover rotates such that the gas discharge port hole and the cover hole are matched with each other, and the internal gas is discharged through the matched holes.

The cover hole may be formed to be equal to or larger than the size of the gas discharge port hole.

A secondary battery according to another embodiment of the present disclosure may include a sealing member surrounding the gas discharge port and the cover.

The gas discharge port hole and the cover hole are positioned to be spaced apart from each other, and the sealing member may be formed to surround the cover.

The sealing member may comprise an epoxy material.

The sealing member is formed to fill the concave portion, and the bottom of the battery case, in which the sealing member is formed, may be formed of a flat surface.

The gas discharge port and the cover may have a cylindrical shape.

According to still another aspect of the present disclosure, there is provided an apparatus including the above secondary battery.

Advantageous effects

According to the embodiments of the present disclosure, according to the configuration of the gas discharge port and the cover formed in the battery case, the degassing process is performed after the activation process of the cylindrical battery, so that the gas inside the secondary battery can be effectively discharged. Accordingly, the internal gas, which causes the long-term life of the secondary battery to be reduced, is discharged, so that the long-term life of the secondary battery can be improved.

The effects of the present disclosure are not limited to the above-described effects, and additional other effects not described above will be clearly understood by those skilled in the art from the detailed description and the accompanying drawings.

Drawings

Fig. 1 is a cross-sectional perspective view of a secondary battery according to an embodiment of the present disclosure;

FIG. 2 is an enlarged and illustrated partial cross-sectional view of portion "A" of FIG. 1;

fig. 3 is a cross-sectional view of a secondary battery according to another embodiment of the present disclosure;

fig. 4 is a perspective view of the gas discharge port and cover of fig. 2 and 3;

fig. 5 is a cross-sectional perspective view of a secondary battery according to still another embodiment of the present disclosure; and

fig. 6 is a partial cross-sectional view of portion "B" of fig. 5 enlarged and shown.

Detailed Description

Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the embodiments. The present disclosure may be modified in various different ways and is not limited to the embodiments set forth herein.

Portions irrelevant to the description will be omitted to clearly describe the present disclosure, and like reference numerals denote like elements throughout the specification.

Further, in the drawings, the size and thickness of each element are arbitrarily illustrated for convenience of description, and the present disclosure is not necessarily limited to those shown in the drawings. In the drawings, the thickness of layers, regions, etc. are exaggerated for clarity. In the drawings, the thickness of some layers or regions are exaggerated for convenience of description.

In addition, it will be understood that when an element such as a layer, film, region or sheet is referred to as being "on" or "over" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, it means that there are no other intervening elements present. Further, the words "above" or "above" mean disposed on or below the reference portion, and not necessarily "on" or "above" the reference portion toward the opposite direction of gravity.

Furthermore, throughout the specification, when a portion is referred to as "comprising" a certain component, it means that the portion may include other components without excluding other components, unless otherwise specified.

Further, in the entire specification, when referred to as a "plane", this means when the target portion is viewed from the upper side, and when referred to as a "cross section", this means when the target portion is viewed from one side of a vertically cut cross section.

Fig. 1 is a cross-sectional perspective view of a secondary battery according to an embodiment of the present disclosure.

Referring to fig. 1, a secondary battery 100 according to an embodiment of the present disclosure includes an electrode assembly 200 and a battery case 300 accommodating the electrode assembly 200. More specifically, the electrode assembly 200 may be impregnated with an electrolyte solution and received in the battery case 300, and the cap assembly 400 may be coupled to the open upper part of the battery case 300 to manufacture the sealed secondary battery 100.

The electrode assembly 200 may have the following winding type structure: the long sheet cathode 210 and the long sheet anode 230 are wound with the separator 220 interposed therebetween.

The cap assembly 400 includes an upper end cap 410 and a safety vent 420, wherein the upper end cap 410 is positioned on the safety vent 420 and may be electrically connected to the safety vent 420 by forming a structure in close contact with each other. The upper end cap 410 protrudes upward at the center and is connected to the cathode 210 of the electrode assembly 200 indirectly or directly via a cathode tab or the like, and may perform a function as a cathode terminal by being connected to an external circuit.

The battery case 300 may be a cylindrical metal can including a bottom 330, and may include a crimping part 340 subjected to a crimping process and a crimping part 350 subjected to a crimping coupling.

The beading part 340 refers to a portion of the battery case 300 that is recessed in the center direction of the electrode assembly 200, and serves to stably couple the cap assembly 400 and prevent the electrode assembly 200 from flowing. Here, the center direction of the electrode assembly 200 refers to a radial direction from the outer circumferential surface of the rolled electrode assembly 200 to the center thereof.

The crimp 350 is positioned above the beading 340 and refers to a portion surrounding the cap assembly 400 for stably coupling the cap assembly 400. Meanwhile, the cap assembly 400 may further include a gasket 430 for increasing a sealing force. Specifically, the gasket 430 is mounted inside the crimp 350 and the beading 340 to increase the sealing force between the cap assembly 400 and the battery case 300. That is, the gasket 430 is positioned between the battery case 300 and the safety vent 420, and the end of the battery case 300 is bent, thereby forming the crimp 350. Thereby, the mounting of the cap assembly 400 and the sealing of the secondary battery 100 may be performed.

The electrode tab 250 is connected to the electrode assembly 200, in particular, extends from the anode 230, and is connected to the bottom 330 of the battery case 300 such that the bottom 330 of the battery case 300 may form an anode terminal. At this time, the electrode tab 250 and the bottom 330 may be welded to each other. In particular, the electrode tab 250 may be formed to deflect to one side based on the center of the electrode assembly 200.

Meanwhile, in the present embodiment, the electrode tab 250 may be an anode tab, but is not limited thereto, and may be a cathode tab. In addition, the welding of one electrode tab 250 and the bottom 330 is mainly described, but the electrode tab 250 may be configured in plurality.

Next, the gas discharge port according to the present embodiment will be described in detail with reference to fig. 1 to 4 and the like.

Fig. 2 is a partial cross-sectional view of the portion "a" of fig. 1, which is enlarged and illustrates a portion of the bottom 330 of the battery case 300 of fig. 1. Fig. 3 is a cross-sectional view of a secondary battery according to another embodiment of the present disclosure. Further, fig. 4 is a perspective view of the gas discharge port and the cover of fig. 2 and 3.

The conventional cylindrical battery does not have a structure capable of discharging harmful gases generated during the activation process to the outside. Therefore, it has been pointed out that a cylindrical battery, which is impossible to discharge harmful gases, may cause a problem of shortened life. Therefore, a new structure for introducing a degassing process capable of discharging the generated harmful gas after performing the activation process is required.

Accordingly, referring to fig. 1, the secondary battery 100 according to the present embodiment includes an electrode assembly 200, a battery case 300 accommodating the electrode assembly 200, and a concave portion 335 recessed from a bottom 330 of the battery case 300 in a direction toward the inside of the battery case 300, wherein a gas discharge port 500 is formed in the concave portion 335. At this time, the direction toward the inside of the battery case 300 means a direction toward the inside of the electrode assembly 200, which is received with respect to the battery case 300. Thus, a discharge passage for performing the degassing process can be ensured. Further, the concave portion 335 is formed to be concave in a direction toward the inside of the battery case 300, so that the gas discharge port 500, which does not protrude to the outside, can be formed.

Specifically, the secondary battery 100 according to the present embodiment includes the electrode tab 250 connected to the electrode assembly 200, wherein the recess 335 may be formed in the bottom 330 of the battery case 300 where the electrode tab 250 is not formed. At this time, the electrode tab 250 may be connected to the anode 230, and the electrode tab 250 may be an anode tab.

Further, the recess 335 is formed at the above-described position, so that the gas discharge port 500 may also be formed on the bottom 330 of the battery case 300 where the electrode tab 250 is not formed. In addition, the gas discharge port 500 is formed to be connected to the bottom 330 of the battery case 300, so that the gas formed in the battery case 300 can be discharged.

As described above, the recess 335 is formed at the bottom of the battery case 300, where the electrode tab 250 is not formed, and the gas discharge port 500 is formed in the recess 335, so that the occurrence of defects during welding can be minimized.

In particular, the gas discharge ports 500 are formed at opposite sides of the electrode tab 250, so that it is possible to minimize obstacles on a gas discharge path and achieve an effect of improving gas discharge efficiency. In addition, since the portion forming the gas discharge port 500 can be visually understood, the position of the electrode tab 250 formed inside can be deduced, thereby facilitating the subsequent disassembly analysis.

The bottom 330 may be formed thicker than the side surface portion of the battery case 300. As described above, by forming the thickness of the bottom 330 thicker than the side surface portion of the battery case 300, the concave portion 335 that is concave from the bottom 330 in the direction toward the inside of the battery case 300 may be formed, and the gas discharge portion 500 may be formed on the concave portion 335.

Meanwhile, referring to fig. 2 to 4, the secondary battery 100 according to the present embodiment may further include a cover 600 covering the gas discharge port 500. Further, the gas discharge port 500 and the cover 600 are formed with holes such that the gas discharge port hole 510 may be formed in the gas discharge port 500, and the cover hole 610 may be formed in the cover 600. In particular, referring to fig. 4, holes are formed in each of the gas discharge port 500 and the cover 600, so that a structure for discharging the internal gas can be formed.

At this time, the cover 600 may be rotated in a state of being fitted to the gas discharge port 500, and by the rotation, the gas discharge port hole 510 and the cover hole 610 may be matched with each other. That is, the gas discharge port hole 510 and the cover hole 610 are matched with each other, and the internal gas may be discharged to the outside through the matched holes.

Meanwhile, as described above, since the cover 600 is rotatable, the cover 600 is rotated and the gas discharge port hole 510 and the cover hole 610 are positioned to be spaced apart from each other, so that the gas discharge can be interrupted. Fig. 2 shows that the gas discharge port hole 510 and the cover hole 610 are positioned in opposite directions to each other, but is not limited thereto, and may include the following structures: in this structure, the gas discharge port hole 510 and the cover hole 610 are positioned to be spaced apart from each other such that the holes do not overlap. Accordingly, the gas discharge port 500 may be opened and closed by rotating the cover 600.

Further, in order to facilitate gas discharge by matching the gas discharge port hole 510 and the cover hole 610 as described above, the cover hole 610 may be formed to be equal to or larger than the size of the gas discharge port hole 510. In order to prevent the internal gas moving through the gas discharge port hole 510 from being blocked by the external structure, the cover hole 610 preferably has the above-mentioned size, but is not limited thereto.

Meanwhile, the gas discharge port 500 and the cover 600 may have a cylindrical shape. Specifically, the gas discharge port 500 may have a cylindrical shape with a closed lower end. In addition, the cover 600 may have a cylindrical shape with an empty interior and a closed lower end to surround the gas discharge port 500, and may have a cylindrical shape with a volume larger than that of the gas discharge port 500. Accordingly, the cover 600 may be formed to surround the gas discharge port 500, and as an example, the cover 600 may be closely coupled to the gas discharge port 500, but is not limited thereto.

Further, referring to fig. 3, the secondary battery 100 according to another embodiment of the present disclosure may include threads 520 and 620 formed in the gas discharge port 500 and the cover 600, respectively. That is, the screw thread 520 formed in the gas discharge port 500 and the screw thread 620 formed in the cover 600 are engaged by the cover 600, and the coupling force between the gas discharge port 500 and the cover 600 can be further enhanced.

In particular, even when the screw thread 520 of the gas discharge port 500 and the screw thread 620 of the cover 600 are coupled to each other, the following structure may be included: in this structure, the gas discharge port hole 510 and the cover hole 610 are spaced apart from each other such that the holes do not overlap each other. Accordingly, the gas discharge port 500 may be opened and closed by the rotation of the cover 600. Further, as described above, by further enhancing the coupling force or the coupling force between the gas discharge port 500 and the cover 600, it is possible to seal the gas discharge port 500 after the degassing process and secure the stability of the secondary battery.

Next, with reference to fig. 5 and 6, a secondary battery according to still another embodiment of the present disclosure will be described. Since there is a content overlapping with the above-described content, only a content different from that of the secondary battery according to one embodiment of the present disclosure will be described below.

Fig. 5 is a cross-sectional perspective view of a secondary battery according to still another embodiment of the present disclosure. Fig. 6 is a partial cross-sectional view of portion "B" of fig. 5 enlarged and shown.

Referring to fig. 5 and 6, in order to fix the gas discharge port 500 and the cover 600, the secondary battery according to the present embodiment may further include a sealing member 700 surrounding the gas discharge port 500 and the cover 600.

In particular, when additional gas discharge is not required after the degassing process is completed, it is required to prevent the gas discharge port hole 510 and the cover hole 610 from being matched and to prevent the cover 600 from being further rotated.

Accordingly, the secondary battery according to the present embodiment may be configured such that the gas discharge port hole 510 and the cover hole 610 are positioned to be spaced apart from each other, and the sealing member 700 surrounds the cover 600. In particular, the sealing member 700 may include a cover hole 610 to enclose the entire cover 600.

In addition, the sealing member 700 is formed to fill the recess 335, and the bottom 330 of the battery case 300, which forms the sealing member 700, may be formed of a flat surface. That is, by filling the sealing member 700 in the recess 335, the entirety of the bottom 330 of the battery case 300 may form a flat surface, and the bottom 330 may be formed of the flat surface. However, the sealing member 700 may also include filling only a portion of the recess 335, and may also include a case where the bottom 330 does not form a flat surface and has a partially recessed portion.

At this time, the material of the sealing member 700 is not limited, but may include an epoxy material. In particular, the sealing member 700 may include one or more materials selected from epoxy and epoxy resin. The sealing member 700 formed of the above-described material prevents the rotation of the gas discharge port 500 and the cover 600 and fills the recess 335, thereby improving the stability of the secondary battery according to the present embodiment. In addition, the epoxy material, particularly, the epoxy and epoxy resin material has excellent mechanical strength, heat resistance, water resistance, and electrical properties, and can completely block moisture that may flow into the battery from the outside. In particular, by forming the sealing member 700 including the epoxy material, separation or spacing of the cover 600 from the gas discharge port 500 due to external impact and external environmental changes can be minimized.

Terms indicating directions such as front side, rear side, left side, right side, upper side, and lower side have been used in the embodiments of the present disclosure, but the terms used are provided for convenience of description only and may become different according to the position of an object, the position of a viewer, and the like.

The secondary battery according to the embodiments of the present disclosure described above may be applied to various devices. For example, the secondary battery may be applied to vehicle devices such as electric bicycles, electric vehicles, and hybrid electric vehicles, and may be applied to various devices capable of using the secondary battery, but is not limited thereto.

While the preferred embodiments of the present disclosure have been shown and described above, the scope of the present disclosure is not limited thereto, and many changes and modifications may be devised by those skilled in the art using the principles of the present application as defined in the appended claims.

Description of the reference numerals

100: secondary battery

200: electrode assembly

210: cathode electrode

220: partition piece

230: anode

250: electrode tab

300: battery box

330: bottom part

335: concave portion

340: hemming portion

350: crimping part

400: cap assembly

410: upper end cap

420: safety exhaust port

430: gasket for a vehicle

500: gas discharge port

510: gas discharge port hole

600: covering part

610: cover part hole

700: and a sealing member.

Claims (13)

1. A secondary battery, comprising:

an electrode assembly;

a battery case accommodating the electrode assembly; and

a concave portion that is concave from the bottom of the battery case in a direction toward the inside of the battery case,

wherein a gas discharge port is formed in the recessed portion.

2. The secondary battery according to claim 1, comprising:

an electrode tab connected to the electrode assembly,

wherein the recess is formed at the bottom of the battery case where the electrode tab is not formed.

3. The secondary battery according to claim 1, further comprising:

and a covering portion that covers the gas discharge port.

4. The secondary battery according to claim 3, wherein:

the cover is rotatable.

5. The secondary battery according to claim 3, wherein:

forming a gas discharge port hole in the gas discharge port, and

a cover hole is formed in the cover.

6. The secondary battery according to claim 5, wherein:

the cover rotates such that the gas discharge port hole and the cover hole are fitted to each other, and

the internal gas is vented through the mating holes.

7. The secondary battery according to claim 5, wherein:

the cover hole is formed to be equal to or larger than a size of the gas discharge port hole.

8. The secondary battery according to claim 5, comprising:

a sealing member surrounding the gas discharge port and the cover.

9. The secondary battery according to claim 8, wherein:

the gas discharge port hole and the cover hole are positioned to be spaced apart from each other, and the sealing member is formed to surround the cover.

10. The secondary battery according to claim 8, wherein:

the sealing member is formed to fill the concave portion,

the bottom of the battery case forming the sealing member is formed of a flat surface.

11. The secondary battery according to claim 8, wherein:

the sealing member comprises an epoxy material.

12. The secondary battery according to claim 3, wherein:

the gas discharge port and the cover have a cylindrical shape.

13. An apparatus comprising the secondary battery according to claim 1.