Secondary battery and device including the same

Abstract

A secondary battery according to one embodiment of the present invention includes an electrode assembly, a battery case that houses the electrode assembly, and a recess that recesses from a bottom of the battery case toward an inside of the battery case, and a gas exhaust port is formed in the recess.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0109148 dated August 19, 2021 and Korean Patent Application No. 10-2022-0101288 dated August 12, 2022, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a secondary battery and a device including the same, and more particularly to a secondary battery having an improved long-term life and a device including the same. [Background technology]

[0003] Recently, the demand for portable electronic products such as notebook computers, video cameras, mobile phones, etc. has increased dramatically, and the development of electric vehicles, energy storage batteries, robots, satellites, etc. has progressed in earnest. As a result, much research has been conducted on secondary batteries used as the driving power sources for these products.

[0004] Secondary batteries are classified according to the shape of the battery case into cylindrical batteries in which the electrode assembly is housed in a cylindrical metal case, prismatic batteries in which the electrode assembly is housed in a prismatic metal case, and pouch batteries in which the electrode assembly is housed in a pouch case made of an aluminum laminate sheet. Of these, cylindrical batteries have the advantages of being relatively large in capacity and structurally stable.

[0005] The electrode assembly built into the battery case is a chargeable and dischargeable power generating element having a laminated structure of a positive electrode, a separator, and a negative electrode, and is classified into a jelly roll type, a stack type, and a stack / folding type. The jelly roll type is a long sheet-like positive electrode and a negative electrode coated with an active material, which are wound with a separator interposed between them, the stack type is a type in which a number of positive electrodes and a negative electrodes of a predetermined size are stacked in sequence with a separator interposed between them, and the stack / folding type is a composite structure of the jelly roll type and the stack type. Among them, the jelly roll type electrode assembly has the advantages of being easy to manufacture and having a high energy density per weight.

[0006] Meanwhile, secondary batteries include, for example, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium secondary batteries, etc. Of these, lithium secondary batteries have the advantages of being free to charge and discharge with almost no memory effect compared to nickel-based secondary batteries, a very low self-discharge rate, a high operating voltage, and a high energy density per unit weight, and are therefore widely used in the field of cutting-edge electronic devices.

[0007] At this time, secondary batteries are manufactured by storing an electrode assembly in a battery case, and then undergo an activation process in which the battery is left at high temperature and charged / discharged several times, during which a large amount of gas is generated inside the secondary battery. At this time, in the case of pouch-type batteries, the gas can be discharged through a degassing process that releases the gas generated after the activation process, but conventional cylindrical batteries were unable to discharge the internal gas due to the lack of a degassing process.

[0008] As a result, conventional cylindrical batteries have a problem in that the gas generated during the activation process cannot be immediately released to the outside, resulting in a reduced long-term battery life.

[0009] Therefore, there is a need for a new structure that can enable the degassing process of cylindrical batteries to proceed, thereby enabling internal gas to be released to the outside and improving the long-term life of the batteries. Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a secondary battery having an improved long-term life and a device including the same.

[0011] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0012] A secondary battery according to one embodiment of the present invention includes an electrode assembly, a battery case that houses the electrode assembly, and a recess that recesses from a bottom of the battery case toward an inside of the battery case, and a gas exhaust port is formed in the recess.

[0013] The secondary battery includes an electrode tab connected to the electrode assembly, and the recess is formed in a bottom portion of the battery case where the electrode tab is not formed.

[0014] The secondary battery may further include a cover portion covering the gas exhaust port.

[0015] The lid is rotatable.

[0016] The gas outlet has a gas outlet hole, and the cover has a cover hole.

[0017] The cover is rotated so that the gas outlet hole and the cover hole are aligned, and the internal gas is discharged through the aligned holes.

[0018] The cover hole may be formed to be equal to or larger than the gas outlet hole.

[0019] A secondary battery according to another embodiment of the present invention may include a sealing member surrounding the gas exhaust port and the cover.

[0020] The gas outlet hole and the cover hole are spaced apart from each other, and the sealing member is formed to surround the cover.

[0021] The sealing member may include an epoxy material.

[0022] The sealing member is formed to fill the recess, and the bottom of the battery case on which the sealing member is formed is formed to be flat.

[0023] The gas outlet and the lid may have a cylindrical shape.

[0024] A device according to yet another embodiment of the present invention includes the secondary battery. Effect of the Invention

[0025] According to the embodiment of the present invention, the gas inside the secondary battery can be effectively discharged by performing a degassing process after the activation process of the cylindrical battery due to the configuration of the gas exhaust port and the cover formed in the battery case. Therefore, the long-term life of the secondary battery can be improved by discharging the internal gas, which is the cause of the deterioration of the long-term life of the secondary battery.

[0026] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief description of the drawings]

[0027] [Figure 1] 1 is a cross-sectional perspective view of a secondary battery according to an embodiment of the present invention; [Diagram 2] 2 is an enlarged partial cross-sectional view of part "A" in FIG. 1. [Diagram 3]4 is a cross-sectional view of a secondary battery according to another embodiment of the present invention. [Figure 4] FIG. 4 is a perspective view of the gas outlet and the lid of FIGS. 2 and 3. [Diagram 5] FIG. 4 is a cross-sectional perspective view of a secondary battery according to still another embodiment of the present invention. [Figure 6] FIG. 6 is an enlarged partial cross-sectional view showing part “B” in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which: FIG. 1 is a block diagram of a semiconductor device according to an embodiment of the present invention;

[0029] In order to clearly explain the present invention, parts that are not necessary for the explanation will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0030] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, thicknesses are enlarged to clearly express various layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0031] In addition, when a part such as a layer, film, region, or plate is said to be "on" another part, this includes not only the case where it is "directly on" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly on" another part, it means that there is no other part in between. Furthermore, being "on" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" in the opposite direction of gravity.

[0032] In addition, throughout the specification, when a part "comprises" a certain element, this means that it can further include other elements, not excluding other elements, unless specifically stated to the contrary.

[0033] Furthermore, throughout the specification, a reference to "in a plane" means that the part is viewed from above, and a reference to "in cross section" means that the part is viewed from the side through a vertical cut.

[0034] FIG. 1 is a cross-sectional perspective view of a secondary battery according to an embodiment of the present invention.

[0035] 1, a secondary battery 100 according to an embodiment of the present invention includes an electrode assembly 200 and a battery case 300 that houses the electrode assembly 200. More specifically, the electrode assembly 200 is impregnated with an electrolyte and housed in the battery case 300, and a cap assembly 400 is attached to an open top of the battery case 300 to form a sealed secondary battery 100.

[0036] The electrode assembly 200 may have a jelly-roll structure in which a long sheet-like positive electrode 210 and a negative electrode 230 are wound with a separator 220 interposed between them.

[0037] The cap assembly 400 includes an upper cap 410 and a safety vent 420, and the upper cap 410 is positioned on the safety vent 420 and is electrically connected to the safety vent 420 by forming a mutually adherent structure therewith. The upper cap 410 protrudes upward at the center and is directly or indirectly connected to the positive electrode 210 of the electrode assembly 200 via a positive electrode tab or the like, and can function as a positive electrode terminal by connecting to an external circuit.

[0038] The battery case 300 may be a cylindrical metal can including a bottom portion 330, and may include a beading portion 340 that is processed by beading and a crimping portion 350 that is joined by crimping.

[0039] The beading portion 340 refers to a portion of the battery case 300 that is recessed toward the center of the electrode assembly 200, and serves to stably attach the cap assembly 400 and prevent the electrode assembly 200 from moving. Here, the center direction of the electrode assembly 200 refers to the radial direction from the outer periphery of the jelly-roll-shaped electrode assembly 200 to its center.

[0040] The crimping portion 350 is located on the upper portion of the beading portion 340 and refers to a portion surrounding the cap assembly 400, for stable coupling of the cap assembly 400. Meanwhile, the cap assembly 400 may further include a gasket 430 for increasing the sealing force. Specifically, the gasket 430 is attached to the inside of the crimping portion 350 and the beading portion 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 crimping portion 350 is formed by bending the end of the battery case 300. In this way, the cap assembly 400 is attached and the secondary battery 100 is sealed.

[0041] The electrode tab 250 is connected to the electrode assembly 200, and in particular, extends from the negative electrode 230 and is connected to the bottom 330 of the battery case 300, so that the bottom 330 of the battery case 300 may form a negative electrode terminal. At this time, the electrode tab 250 and the bottom 330 may be joined to each other by welding. In particular, the electrode tab 250 is formed to be biased to one side with respect to the center of the electrode assembly 200.

[0042] Meanwhile, in this embodiment, the electrode tab 250 may be a negative electrode tab, but is not limited thereto, and may be a positive electrode tab. Also, although the above description is based on welding one electrode tab 250 to the bottom portion 330, a plurality of electrode tabs 250 may be provided.

[0043] The gas exhaust port according to this embodiment will be described in detail below with reference to Figs. 1 to 4 etc.

[0044] Fig. 2 is a partial cross-sectional view showing an enlarged view of part "A" in Fig. 1, and shows an enlarged view of a part of the bottom 330 of the battery case 300 in Fig. 1. Fig. 3 is a cross-sectional view of a secondary battery according to another embodiment of the present invention. Fig. 4 is a perspective view of the gas exhaust port and the lid shown in Figs. 2 and 3.

[0045] Conventional cylindrical batteries lack a structure that can release harmful gases generated during the activation process. As a result, cylindrical batteries that cannot release harmful gases can have problems with shortened lifespan, and so a new structure was needed to introduce a degassing process that can release harmful gases generated after the activation process.

[0046] 1, the secondary battery 100 according to the present embodiment includes an electrode assembly 200, a battery case 300 housing the electrode assembly 200, and an indentation 335 indented from a bottom 330 of the battery case 300 toward the inside of the battery case 300, and a gas outlet 500 is formed in the indentation 335. At this time, the inward direction of the battery case 300 means the inner direction in which the electrode assembly 200 is housed in the battery case 300. Therefore, a gas outlet passage for a degassing process can be secured. Also, by forming the indentation 335 indented toward the inside of the battery case 300, a gas outlet 500 that does not protrude to the outside can be formed.

[0047] Specifically, the secondary battery 100 according to this embodiment includes an electrode tab 250 connected to the electrode assembly 200, and the recessed portion 335 is formed in a bottom portion 330 of the battery case 300 where the electrode tab 250 is not formed. In this case, the electrode tab 250 is connected to the negative electrode 230, and the electrode tab 250 may be a negative electrode tab.

[0048] In addition, since the recess 335 is formed at the above position, the gas outlet 500 is also formed on the bottom 330 of the battery case 300 where the electrode tab 250 is not formed. Furthermore, the gas outlet 500 is formed to be connected to the bottom 330 of the battery case 300, so that gas formed within the battery case 300 can be discharged.

[0049] As described above, the recess 335 is formed in the bottom of the battery case 300 where the electrode tab 250 is not formed, and the gas exhaust port 500 is formed in the recess 335, thereby minimizing the occurrence of defects during welding.

[0050] In particular, it is possible to improve the efficiency of gas exhaust by minimizing obstructions on the gas exhaust path by forming the gas exhaust port 500 on the opposite side of the electrode tab 250. In addition, since the portion where the gas exhaust port 500 is formed can be seen from the outside, it is possible to infer the position of the electrode tab 250 formed inside, which may facilitate subsequent disassembly analysis.

[0051] The bottom 330 is formed to be thicker than the side of the battery case 300. As described above, by forming the bottom 330 to be thicker than the side of the battery case 300, an indentation 335 indenting from the bottom 330 toward the inside of the battery case 300 is formed, and a gas outlet 500 is formed on the indentation 335.

[0052] 2 to 4, the secondary battery 100 according to this embodiment may further include a cover 600 covering the gas exhaust port 500. In addition, the gas exhaust port 500 and the cover 600 have holes formed therein, and the gas exhaust port 500 has a gas exhaust port hole 510, and the cover 600 has a cover hole 610. In particular, referring to Fig. 4, the gas exhaust port 500 and the cover 600 each have a hole formed therein, thereby forming a structure for discharging internal gas.

[0053] At this time, the cover 600 can rotate while being inserted and coupled to the gas exhaust port 500, and the rotation allows the gas exhaust port hole 510 to coincide with the cover hole 610. That is, the gas exhaust port hole 510 coincides with the cover hole 610, and the internal gas is discharged to the outside through the coincident holes.

[0054] Meanwhile, as described above, since the cover 600 is rotatable, the gas exhaust hole 510 and the cover hole 610 can be positioned apart from each other by rotating the cover 600, thereby stopping the exhaust of gas. Although the gas exhaust hole 510 and the cover hole 610 are shown positioned in opposite directions from each other in FIG. 2, the gas exhaust hole 510 and the cover hole 610 can be positioned apart from each other so that the holes do not overlap. Therefore, the gas exhaust hole 500 can be opened and closed by rotating the cover 600.

[0055] Also, in order to facilitate gas discharge by aligning the gas outlet 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 gas outlet hole 510. In order to prevent the internal gas moving through the gas outlet hole 510 from being blocked by an external structure, it is preferable that the cover hole 610 has the above size, but is not limited thereto.

[0056] Meanwhile, the gas exhaust port 500 and the lid 600 may have a cylindrical shape. Specifically, the gas exhaust port 500 may be a cylindrical shape with a closed lower end. The lid 600 may be a cylindrical shape with an open interior surrounding the gas exhaust port 500 and a closed lower end, or may be a cylindrical shape having a larger volume than the gas exhaust port 500. Thus, the lid 600 is formed to surround the gas exhaust port 500, and as an example, the lid 600 can be tightly coupled to the gas exhaust port 500, but is not limited thereto.

[0057] 3, the secondary battery 100 according to another embodiment of the present invention may include threads 520, 620 formed on the gas outlet 500 and the cover 600, respectively. That is, the threads 520 formed on the gas outlet 500 and the threads 620 formed on the cover 600 may be engaged with each other by the cover 600, thereby further strengthening the bonding force between the gas outlet 500 and the cover 600.

[0058] In particular, even when the screw threads 520, 620 of the gas outlet 500 and the cover 600 are coupled to each other, the gas outlet hole 510 and the cover hole 610 may be spaced apart from each other so that the holes do not overlap each other. Therefore, the gas outlet 500 can be opened and closed by rotating the cover 600. In addition, as described above, by further strengthening the coupling or binding force between the gas outlet 500 and the cover 600, the gas outlet 500 can be sealed after the degassing process, and the stability of the secondary battery can be ensured.

[0059] Hereinafter, a secondary battery according to another embodiment of the present invention will be described with reference to Figures 5 and 6. Since there are some overlapping parts with the contents described above, only the contents different from the secondary battery according to the embodiment of the present invention will be described below.

[0060] Fig. 5 is a cross-sectional perspective view of a secondary battery according to still another embodiment of the present invention, and Fig. 6 is a partial cross-sectional view showing an enlarged portion "B" of Fig. 5.

[0061] 5 and 6, in order to fix the gas outlet 500 and the cover 600, the secondary battery according to this embodiment may further include a sealing member 700 surrounding the gas outlet 500 and the cover 600.

[0062] Specifically, after the degassing process is completed, if no additional gas discharge is required, it is necessary to prevent the gas discharge hole 510 and the lid hole 610 from coinciding with each other and to prevent additional rotation of the lid 600.

[0063] Therefore, in the secondary battery according to this embodiment, the gas outlet hole 510 and the cover hole 610 are spaced apart from each other, and the sealing member 700 is formed to surround the cover 600. In particular, the sealing member 700 may include one that surrounds the entire cover 600 including the cover hole 610.

[0064] In addition, the sealing member 700 is formed to fill the indentation 335, and the bottom 330 of the battery case 300 on which the sealing member 700 is formed is formed to have a flat surface. That is, by filling the indentation 335 with the sealing member 700, the entire bottom 330 of the battery case 300 can form a flat surface, and the bottom 330 is formed to have a flat surface. However, the sealing member 700 may include a member that fills only a part of the indentation 335, and may include a member in which the bottom 330 is not flat but has a partially indented portion.

[0065] At this time, the material of the sealing member 700 is not limited, but may include an epoxy material. Specifically, the sealing member 700 may include one or more materials selected from epoxy and epoxy resin. The sealing member 700 formed of the material can prevent the gas exhaust port 500 and the cover 600 from rotating and fill the recessed portion 335, thereby improving the stability of the secondary battery according to the present embodiment. In addition, the epoxy material, specifically, the epoxy and epoxy resin materials, have excellent mechanical strength, heat resistance, water resistance, and electrical properties, and can completely block moisture that may flow into the inside of the battery from the outside. In particular, the formation of the sealing member 700 including the epoxy material can minimize the separation or separation of the cover 600 from the gas exhaust port 500 due to external impact and changes in external conditions.

[0066] In this embodiment, terms indicating directions such as front, back, left, right, up, and down are used, but these terms are merely for convenience of explanation and may differ depending on the position of the object of interest, the position of the observer, etc.

[0067] The secondary battery according to the present embodiment described above can be applied to various devices, specifically, to transportation means such as electric bicycles, electric cars, and hybrid vehicles, but is not limited thereto, and can be applied to various devices that can use secondary batteries.

[0068] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0069] 100: Secondary battery 200: Electrode assembly 210: Positive electrode 220: Separation membrane 230: Negative electrode 250: Electrode tab 300: Battery case 330: Bottom 335: Bay area 340: Beading section 350: Crimping section 400: Cap assembly 410: Top cap 420: Safety vent 430: Gasket 500: Gas outlet 510: Gas exhaust hole 600: Lid 610: Lid hole 700: Sealing member

Claims

1. An electrode assembly; a battery case that houses the electrode assembly; a recessed portion recessed from a bottom portion of the battery case toward an inside of the battery case, The recess is provided with a gas exhaust port that can be opened and closed. Further comprising a lid portion for covering the gas exhaust port, The gas exhaust port has a gas exhaust port hole, and the cover has a cover hole, A sealing member surrounding the gas exhaust port and the lid portion is included. Cylindrical secondary battery.

2. an electrode tab connected to the electrode assembly; The cylindrical secondary battery according to claim 1 , wherein the recess is formed in a bottom portion of the battery case where the electrode tab is not formed.

3. An electrode assembly, a battery case that houses the electrode assembly; a recessed portion recessed from a bottom portion of the battery case toward an inside of the battery case, The recess is provided with a gas exhaust port that can be opened and closed. Further comprising a lid portion for covering the gas exhaust port, The cylindrical secondary battery, wherein the lid is rotatable.

4. The gas outlet has a gas outlet hole formed therein, The cylindrical secondary battery according to claim 3 , wherein the cover has a cover hole formed therein.

5. The lid is rotated so that the gas outlet hole and the lid hole are aligned, 5. The cylindrical secondary battery according to claim 4, wherein the aligned holes allow internal gas to escape.

6. The cylindrical secondary battery of claim 4 , wherein the cover hole is formed to be equal to or larger than the gas outlet hole.

7. The cylindrical secondary battery according to claim 4 , further comprising a sealing member surrounding the gas exhaust port and the lid portion.

8. the gas outlet hole and the cover hole are spaced apart from each other; The cylindrical secondary battery according to claim 7 , wherein the sealing member is formed so as to surround the lid portion.

9. The sealing member is formed to fill the recess, The cylindrical secondary battery according to claim 7 , wherein a bottom of the battery case on which the sealing member is formed is formed into a flat surface.

10. The cylindrical secondary battery according to claim 7 , wherein the sealing member includes an epoxy material.

11. The cylindrical secondary battery according to claim 3 , wherein the gas exhaust port and the lid portion have a cylindrical shape.

12. A device comprising the cylindrical secondary battery according to any one of claims 1 to 11.

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