Secondary battery

Abstract

A secondary battery according to an embodiment of the present invention may comprise: an electrode structure including a first electrode, a second electrode, and a separator; and a battery case in which the electrode structure is accommodated and which is sealed. Here, the battery case may comprise a first case and a second case made of different materials.

Description

secondary battery

[0001] This application claims the benefit of Korean Patent Application No. 10-2023-0121562, filed with the Korean Intellectual Property Office on September 13, 2023, the entire disclosure of which is incorporated herein by reference.

[0002] The present invention relates to a secondary battery, and more specifically, to a secondary battery including a battery case in which cases made of different materials are combined.

[0003] Secondary batteries are batteries that can be reused by charging even after discharge, and can be used as an energy source for small devices such as mobile phones, tablet PCs, and vacuum cleaners, and are also used as an energy source for medium and large devices such as automobiles and ESS (Energy Storage Systems) for smart grids.

[0004] Cells, which are the basic units of secondary batteries, can be classified into cylindrical cells in which the electrode structure is embedded in a cylindrical metal can, square cells in which the electrode structure is embedded in a square metal can, and pouch cells in which the electrode structure is embedded in a flexible pouch case.

[0005] In general, square cells have the advantage of high structural stability and resistance to external impacts, while pouch cells are relatively light and can be manufactured in various sizes and shapes. Conversely, square cells are relatively heavy, and pouch cells have the disadvantage of low structural stability.

[0006] The purpose of the present invention to solve the above problems is to provide a secondary battery having both the advantages of a square cell and a pouch-type cell.

[0007] The purpose of the present invention to solve the above problems is to provide a secondary battery with improved structural stability and lightweight.

[0008] According to one embodiment of the present invention to achieve the above object, a secondary battery may include an electrode structure including a first electrode, a second electrode, and a separator; and a battery case that houses and seals the electrode structure therein. Here, the battery case may include a first case and a second case made of different materials.

[0009] The first case may be formed of an inflexible material, and the second case may be formed of a flexible material.

[0010] The first case can be formed to surround a first electrode portion formed by extending from one end of the electrode structure, and a second electrode portion formed by extending from the other end of the electrode structure.

[0011] The first case may have at least a portion of its area open. Here, the second case may cover the open area of ​​the first case and be sealedly bonded to the first case.

[0012] The second case can be heat-sealed and sealed with the first case by heat and pressure applied to the overlapping portion with the first case.

[0013] The first case has a rectangular parallelepiped shape and may have an open area formed on at least one of the upper surface, the front surface, and the back surface. Here, the open area may be formed such that the length of the open width is greater than the length of the width of the electrode structure.

[0014] The first electrode unit may include a first electrode tab electrically connected to the first electrode and extending from one end of the electrode structure; and a first electrode lead welded to the first electrode tab and extending from one end of the first electrode tab. In addition, the second electrode unit may include a second electrode tab electrically connected to the second electrode and extending from the other end of the electrode structure; and a second electrode lead welded to the second electrode tab and extending from the other end of the second electrode tab.

[0015] Here, the first electrode lead may extend in one direction and penetrate one side of the first case, and the second electrode lead may extend in the other direction and penetrate the other side of the first case.

[0016] The first case may further include a first insulating member fixedly inserted into one side of the first case and having a through hole formed therein through which the first electrode lead hermetically passes; and a second insulating member fixedly inserted into the other side of the first case and having a through hole formed therein through which the second electrode lead hermetically passes.

[0017] The secondary battery may further include a venting door for discharging gas generated within the battery case to the outside. Here, the venting door may be provided in a specific area of ​​the first case.

[0018] According to the above-described embodiment of the present invention, a lightweight secondary battery having high structural stability can be manufactured.

[0019] Figure 1 is a perspective view of a secondary battery according to an embodiment of the present invention.

[0020] Figure 2 is a perspective view of an electrode structure according to an embodiment of the present invention.

[0021] Figure 3 is a perspective view of a battery case according to an embodiment of the present invention.

[0022] Figure 4 is a perspective view of a first case according to an embodiment of the present invention.

[0023] FIG. 5 is a perspective view of a secondary battery including a battery case according to an embodiment of the present invention.

[0024] Figure 6 is a front view of a secondary battery (without the second case joined) according to an embodiment of the present invention.

[0025] Figure 7 is a vertical cross-sectional view of the secondary battery illustrated in Figure 6.

[0026] Figure 8 is a front view of a secondary battery (with the second case joined) according to an embodiment of the present invention.

[0027] Figure 9 is a plan view of the secondary battery illustrated in Figure 8.

[0028] Figure 10 is a bottom view of the secondary battery illustrated in Figure 8.

[0029] 100: Battery Case

[0030] 200: Electrode structure

[0031] 110: Case 1

[0032] 111: Insulating member

[0033] 112: Venting Door

[0034] 120: Case 2

[0035] 310: Electrode tab

[0036] 320: Electrode lead

[0037] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Throughout the description of each drawing, similar reference numerals have been used to designate similar components.

[0038] Terms such as "first," "second," "A," and "B" may be used to describe various components, but these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, the first component could be referred to as the "second component," and similarly, the second component could also be referred to as the "first component." The term "and / or" includes any combination of multiple related items listed or any one of multiple related items listed.

[0039] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0040] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0041] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0042] Hereinafter, various embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0043]

[0044] Figure 1 is a perspective view of a secondary battery according to an embodiment of the present invention.

[0045] A secondary battery according to an embodiment of the present invention may be configured to include a battery case (100) and an electrode structure (200).

[0046] The electrode structure (200) may include a first electrode, a second electrode, and a separator. Here, the first electrode may correspond to the positive electrode, and the second electrode may correspond to the negative electrode. Meanwhile, in the present invention, the active materials of each of the first and second electrodes are not limited to specific chemicals.

[0047] In the present invention, the electrode structure (200) is not limited to a specific structure, and for example, the electrode structure (200) may correspond to a stacked structure in which a first electrode, a second electrode, and a separator manufactured to a certain area are sequentially stacked, or a rolled structure in which a first electrode, a second electrode, and a separator manufactured to a certain area are sequentially stacked and then rolled.

[0048] The battery case (100) corresponds to a sealed structure that houses an electrode structure (200) inside.

[0049] The battery case (100) may have a rectangular parallelepiped shape. Here, the rectangular parallelepiped shape may mean a polyhedral structure including a front surface, a back surface, a left surface, a right surface, a top surface, and a bottom surface, even if the corners of each surface are rounded and thus not an exact rectangular parallelepiped shape.

[0050] On the outer surface of the battery case (100), an electrode terminal electrically connected to the electrode structure (200) may be provided. Here, the electrode terminal may include a first electrode terminal connected to the first electrode, and a second electrode terminal connected to the second electrode.

[0051] The battery case (100) can have an electrolyte solution injected into it. Here, the battery case (100) can have an injection port formed therein for injecting the electrolyte solution.

[0052] The battery case (100) may be provided with a venting door to discharge gases generated internally to the outside. Here, the venting door may refer to a structure that opens or breaks when the internal pressure exceeds a certain pressure, thereby discharging internal gases.

[0053] A plurality of secondary batteries according to the present invention can be sequentially stacked from the front to the back and included in a battery module.

[0054]

[0055] Figure 2 is a perspective view of an electrode structure according to an embodiment of the present invention.

[0056] The electrode structure (200) may be a stacked structure in which a first electrode, a second electrode, and a separator manufactured to a certain area are sequentially stacked.

[0057] The electrode structure (200) can be connected to a first electrode portion and a second electrode portion formed on each side for electrical connection with an external device.

[0058] The first electrode portion may include a first electrode tab (310-1) and a first electrode lead (320-1). Here, the first electrode tabs (310-1) are electrically connected to each of the first electrode layers and may extend from one end of the electrode structure (200). The first electrode lead (320-1) may be welded to the first electrode tabs (310-1) and may extend from one end of the first electrode tabs (310-1).

[0059] The second electrode portion may include a second electrode tab (310-2) and a second electrode lead (320-2). Here, the second electrode tabs (310-2) are electrically connected to each of the second electrode layers and may extend from the other end of the electrode structure (200). The second electrode lead (320-2) may be welded to the second electrode tabs (310-2) and may extend from the other end of the second electrode tabs (310-2).

[0060] The first electrode tabs (310-1) and the first electrode leads (320-1) can be welded in a straight line shape. That is, as illustrated in FIG. 2, the bead shape (B) formed by welding between the first electrode tabs (310-1) and the first electrode leads (320-1) can be a straight line of a certain length.

[0061] Additionally, the second electrode tabs (310-2) and the second electrode leads (320-2) can be welded in a straight line shape. That is, as illustrated in FIG. 2, the bead shape (B) formed by welding between the second electrode tabs (310-2) and the second electrode leads (320-2) can be a straight line of a certain length.

[0062]

[0063] Figure 3 is a perspective view of a battery case according to an embodiment of the present invention.

[0064] Referring to FIG. 3, the battery case may include a first case (110) and a second case (120). Here, the first case (110) and the second case (120) may be sealed and bonded to prevent leakage of the electrolyte contained therein.

[0065] The first case (110) and the second case (120) may be formed of different materials. Here, the first case (110) may be formed of an inflexible material, and the second case (120) may be formed of a flexible material.

[0066] For example, the first case (110) may be manufactured to be formed of a solid metal (e.g., aluminum) so as to maintain a specific shape. In addition, the second case (120) may be manufactured to be formed of a laminate sheet in which a resin layer and a metal layer (e.g., aluminum sheet) are laminated and bonded so as to allow a certain level of shape deformation.

[0067] The first case (110) may have a shape in which at least a portion of the area is open. For example, the first case (110) may have a rectangular parallelepiped shape, and an open area may be formed on at least one of the top, front, and back surfaces.

[0068] Here, the second case (120) can cover the open area of ​​the first case (110) and be sealedly bonded with the first case (110). For example, if some areas of the top and front surfaces of the first case (110) are open, the second case (120) can cover the open area of ​​the first case (110) and be sealedly bonded with the first case (110).

[0069] The second case (120) can be heat-fused and sealed with the first case (110) by heat and pressure applied to the overlapping portion with the first case (110). For example, the second case (120) can be manufactured with an area larger than the area of ​​the open area of ​​the first case (110) so as to cover the open area. Here, heat and pressure can be applied to the overlapping portion of the second case (120) and the first case (110), so that the first case (110) and the second case (120) can be sealed and sealed with each other.

[0070]

[0071] Figure 4 is a perspective view of a first case according to an embodiment of the present invention.

[0072] The first case (110) may be formed of an inflexible material and may have at least some areas open. For example, as illustrated in FIG. 4, the first case (110) may be manufactured in a form in which some areas of the top, front, and back surfaces are open.

[0073] The first case (110) may have a shape that surrounds (or encloses) the first electrode portion (310-1, 320-1) and the second electrode portion (310-2, 320-2). More specifically, the first case (110) may have a structure in which the central region (A) is open and the two sides have spaces formed therein, as illustrated in FIG. 4. Accordingly, when the electrode structure (200) is accommodated inside the first case (110), the first case (110) surrounds the first electrode portion (310-1, 320-1) and the second electrode portion (310-2, 320-2), thereby improving structural stability.

[0074] The open area (A) of the first case (110) may be formed such that the length (Wo) of the open width is greater than or equal to the length (We) of the width of the electrode structure (200). More specifically, when the width (Wo) of the open area (A) of the first case (110) is formed such that the width (We) of the electrode structure (200) is greater than or equal to the width of the electrode structure (200), the first case (110) surrounds the first electrode portion and the second electrode portion on both sides, and the outer surface of the electrode structure (200) is not entirely wrapped, and the second case (120) covers the open area (A) and the outer surface of the electrode structure (200). Accordingly, when the secondary battery is manufactured as a module by being stacked with other secondary batteries, the pressure of the first cases of adjacent secondary batteries is not applied to both ends of the electrode structure (200), so that a pressure deviation of the electrode structure (200) may not occur.

[0075]

[0076] FIG. 5 is a perspective view of a secondary battery including a battery case according to an embodiment of the present invention.

[0077] Referring to FIG. 5, the battery case may include a first case (110) and a second case (120).

[0078] The first case (110) is formed of an inflexible material and may have an open area formed on at least one of the top, front, and back surfaces. Here, the second case (120) is formed of a flexible material and may cover the open area of ​​the first case (110) and be sealedly bonded to the first case (110).

[0079] The first electrode lead (320-1) may extend in one direction from one end of the first electrode tab (310-1) and penetrate one side of the first case (110). Here, the first case (110) may include a first insulating member (111-1) having a through hole formed therein through which the first electrode lead (320-1) hermetically penetrates. The first insulating member (111-1) may be formed of an insulating material (e.g., a chemically resistant plastic for insulation) and may be configured to be fixedly inserted into one side of the first case (100).

[0080] The second electrode lead (320-2) may extend in the other direction from the other end of the second electrode tab (310-2) and penetrate the other side of the first case (110). Here, the first case (110) may include a second insulating member (111-2) having a through hole formed therein through which the second electrode lead (320-2) hermetically penetrates. The second insulating member (111-2) may be formed of an insulating material (e.g., a chemically resistant plastic for insulation) and may be configured to be fixedly inserted into the other side of the first case (100).

[0081] The battery case (100) may be provided with a venting door (112-1, 112-2) for discharging gas generated internally to the outside. Here, the venting door may refer to a structure that opens or breaks when the internal pressure exceeds a certain pressure, thereby discharging the gas inside.

[0082] The venting door may be formed on one or more of the upper surface, lower surface, front surface, and back surface of the first case (110). For example, the venting door may be provided on one end (112-1) of the upper surface of the first case (110), as illustrated in FIG. 5, or may be provided on the other end (112-2) of the upper surface of the first case (110).

[0083]

[0084] FIG. 6 is a front view of a secondary battery (without the second case joined) according to an embodiment of the present invention, and FIG. 7 is a vertical cross-sectional view of the secondary battery illustrated in FIG. 6.

[0085] The first case (110) is formed of an inflexible material and, as illustrated in FIG. 6, can be manufactured in a form in which some areas of the top, front, and back surfaces are open. Meanwhile, the first case (110), as illustrated in FIG. 7, can be manufactured of a solid metal having a certain thickness.

[0086] The first case (110) may have a shape that surrounds (or encloses) the first electrode portion (310-1, 320-1) and the second electrode portion (310-2, 320-2). More specifically, as illustrated in FIG. 7, the first case (110) has both ends formed in a “ㄷ”-shaped structure to surround the first electrode portion (310-1, 320-1) and the second electrode portion (310-2, 320-2).

[0087] The width (Wo) of the open area (A) of the first case (110) is formed to be greater than the width (We) of the electrode structure (200), so that the first case (110) surrounds the first electrode portions (310-1, 320-1) and the second electrode portions (310-2, 320-2) at both ends, but does not cover the front, back, and top surfaces of the electrode structure (200). Here, the area of ​​the electrode structure (200) that is not covered by the first case (110) can be covered by the second case (120).

[0088] The first electrode lead (320-1) extends in one direction from one end of the first electrode tab (310-1), hermetically penetrates the through hole of the first insulating member (111-1) fixedly inserted into one side of the first case (100), and can be exposed to the outside of the first case (110).

[0089] The second electrode lead (320-2) extends in the other direction from the other end of the second electrode tab (310-2), hermetically penetrates the through hole of the second insulating member (111-2) fixedly inserted into the other side of the first case (110), and can be exposed to the outside of the first case (110).

[0090]

[0091] FIG. 8 is a front view of a secondary battery (with the second case joined) according to an embodiment of the present invention, FIG. 9 is a plan view of the secondary battery illustrated in FIG. 8, and FIG. 10 is a bottom view of the secondary battery illustrated in FIG. 8.

[0092] The second case (120) is formed of a flexible material, covers the open area of ​​the first case (110), and can be sealedly bonded to the first case (110).

[0093] When the first case (110) is manufactured in a form in which some areas of the upper surface, front surface, and back surface are open, as shown in FIG. 6, the second case (120) can be sealed and joined to the first case (110) by covering all of the open areas of the first case (110), as shown in FIGS. 8 to 10.

[0094] Meanwhile, FIG. 10 illustrates a structure in which the second case (120) covers a portion of the bottom surface (lower surface) of the first case (110), but unlike FIG. 10, the second case (120) may be sealed and bonded after surrounding the bottom surface of the first case (110).

[0095]

[0096] The secondary battery according to the various embodiments of the present invention described above exhibits high structural stability and can be made lightweight, as both end portions have a square cell structure and the central portion has a pouch-shaped cell structure.

[0097] Although the present invention has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. An electrode structure comprising a first electrode, a second electrode, and a separator; A battery case is provided therein and is sealed, comprising: The above battery case, A secondary battery comprising a first case and a second case made of different materials.

2. In claim 1, The above first case is formed of an inflexible material, The second case is a secondary battery formed of a flexible material.

3. In claim 2, The first case above is, A secondary battery formed to surround a first electrode portion formed by extending from one end of the electrode structure, and a second electrode portion formed by extending from the other end of the electrode structure.

4. In claim 3, The first case above is, At least some areas are open, The second case above is, A secondary battery covering the open area of ​​the first case and sealingly bonded to the first case.

5. In claim 4, The second case above is, A secondary battery that is sealed and bonded to the first case by heat and pressure applied to the overlapping portion with the first case.

6. In claim 4, The first case above is, A secondary battery having a rectangular parallelepiped shape and having an open area formed on at least one of the upper surface, the front surface, and the back surface.

7. In claim 6, The above open area is, A secondary battery, wherein the length of the open width is formed to be longer than the length of the width of the electrode structure.

8. In claim 3, The above first electrode part, A first electrode tab electrically connected to the first electrode and extending from one end of the electrode structure; and a first electrode lead welded to the first electrode tab and extending from one end of the first electrode tab; The above second electrode part, A secondary battery comprising: a second electrode tab electrically connected to the second electrode and extending from the other end of the electrode structure; and a second electrode lead welded to the second electrode tab and extending from the other end of the second electrode tab.

9. In claim 8, The above first electrode lead, Extending in one direction and penetrating one side of the first case, The above second electrode lead, A secondary battery extending in the other direction and penetrating the other side surface of the first case.

10. In claim 9, The first case above is, A first insulating member fixedly inserted into one side of the first case and having a through hole formed therein through which the first electrode lead hermetically penetrates; and A secondary battery further comprising a second insulating member fixedly inserted into the other side of the first case and having a through hole formed therein through which the second electrode lead hermetically penetrates.

11. In claim 3, It further includes a venting door for discharging gases generated inside the battery case to the outside, The above venting door, A secondary battery provided in a specific area of ​​the above first case.

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