Secondary batteries

Abstract

A secondary battery according to an embodiment of the present invention 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. Here, the battery case may include a first case and a second case made of different materials.

Description

[Technical Field]

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2023-0121562, filed with the Korean Intellectual Property Office on September 13, 2023, and all of the contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

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

[0003] Secondary batteries are batteries that can be reused by recharging after discharge and can be used as energy sources for small devices such as mobile phones, tablet PCs, and vacuum cleaners, as well as medium- to large-sized devices such as automobiles and smart grid ESS (Energy Storage Systems).

[0004] Cells, which are the basic unit of secondary batteries, can be classified into cylindrical cells in which an electrode structure is housed in a cylindrical metal can, prismatic cells in which an electrode structure is housed in a prismatic metal can, and pouch-type cells in which an electrode structure is housed in a flexible pouch case.

[0005] Generally, prismatic cells have the advantage of being highly structurally stable and resistant to external impacts, while pouch-type cells have the advantage of being relatively light and being able to be manufactured in a variety of sizes and shapes. Conversely, prismatic cells are relatively heavy, while pouch-type cells have the disadvantage of being less structurally stable. Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a secondary battery that has the advantages of both prismatic cells and pouch-type cells.

[0007] SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a secondary battery that has improved structural stability and can be made lighter. [Means for solving the problem]

[0008] To achieve the above object, a secondary battery according to one embodiment of the present invention can 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. Here, the battery case can include a first case and a second case made of different materials.

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

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

[0011] The first case may have at least a partial open area, and the second case may be sealed to the first case while covering the open area of ​​the first case.

[0012] The second case may be heat-sealed and joined to the first case by applying heat and pressure to an overlapping portion of the second case and the first case.

[0013] The first case may have a rectangular parallelepiped shape and may have an open area formed on one or more of its top, front, and rear surfaces, wherein the open width of the open area may be equal to or greater than the width of the electrode structure.

[0014] The first electrode portion 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. The second electrode portion 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 through which the first electrode lead passes airtight; and a second insulating member fixedly inserted into the other side of the first case and having a through hole through which the second electrode lead passes airtight.

[0017] The secondary battery may further include a vent door for discharging gas generated inside the battery case to the outside, wherein the vent door may be provided in a specific region of the first case. [Effects of the Invention]

[0018] According to the above-described embodiment of the present invention, a secondary battery having high structural stability and reduced weight can be manufactured. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a perspective view of a secondary battery according to an embodiment of the present invention; [Figure 2] 1 is a perspective view of an electrode structure according to an embodiment of the present invention. [Figure 3] FIG. 1 is a perspective view of a battery case according to an embodiment of the present invention. [Figure 4] FIG. 2 is a perspective view of a first case according to the embodiment of the present invention. [Figure 5] 1 is a perspective view of a secondary battery including a battery case according to an embodiment of the present invention; [Figure 6] 1 is a front view of a secondary battery (without a second case joined) according to an embodiment of the present invention; [Figure 7] FIG. 7 is a vertical cross-sectional view of the secondary battery shown in FIG. [Figure 8] 1 is a front view of a secondary battery (with a second case joined) according to an embodiment of the present invention. [Figure 9] FIG. 9 is a plan view of the secondary battery shown in FIG. [Figure 10] FIG. 9 is a bottom view of the secondary battery shown in FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0020] Because the present invention can be modified in various ways and has various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, it is not intended to limit the present invention to the specific embodiments, but it should be understood that the present invention includes all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention. Similar reference numerals are used to refer to similar components throughout the description of the drawings.

[0021] Terms such as "first," "second," "A," and "B" may be used to describe various components, but the components should not be limited by these terms. These terms are used only to distinguish one component from another. For example, a first component may be termed a "second component," and similarly, a second component may be termed a "first component," without departing from the scope of the present invention. The term "and / or" includes a combination of multiple associated listed items or any of multiple associated listed items.

[0022] When a component is referred to as being "coupled" or "connected" to another component, it is understood that the component may be directly coupled or connected to the other component, but that there may be other components in between. Conversely, when a component is referred to as being "directly coupled" or "directly connected" to another component, it is understood that there are no other components in between.

[0023] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly indicates otherwise. It should be understood that in this application, the terms "comprise" or "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and do not preclude the presence or additional possibility of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0024] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and should not be interpreted as having an ideal or overly formal meaning unless expressly defined in this application.

[0025] Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0026] FIG. 1 is a perspective view of a secondary battery according to an embodiment of the present invention.

[0027] The secondary battery according to the embodiment of the present invention may include a battery case 100 and an electrode structure 200 .

[0028] The electrode structure 200 may include a first electrode, a second electrode, and a separator. Here, the first electrode may correspond to a positive electrode, and the second electrode may correspond to a negative electrode. Meanwhile, in the present invention, the active materials of the first electrode and the second electrode are not limited to a specific chemical substance.

[0029] In the present invention, the electrode structure 200 is not limited to a specific structure, and for example, the electrode structure 200 may be a stacked structure in which a first electrode, a second electrode, and a separator, each made to a certain area, are sequentially stacked, or a wound structure in which a first electrode, a second electrode, and a separator, each made to a certain area, are sequentially stacked and then wound.

[0030] The battery case 100 corresponds to a structure in which the electrode structure 200 is housed and sealed.

[0031] The battery case 100 may have a rectangular parallelepiped shape. Here, the rectangular parallelepiped shape may refer to a polyhedral structure including a front, a back, a left side, a right side, a top, and a bottom, even if the corners of each side are rounded and the shape is not an exact rectangular parallelepiped.

[0032] Electrode terminals electrically connected to the electrode structure 200 may be provided on the outer surface of the battery case 100. Here, the electrode terminals may include a first electrode terminal connected to the first electrode and a second electrode terminal connected to the second electrode.

[0033] An aqueous electrolyte solution may be injected into the battery case 100. Here, the battery case 100 may be formed with an injection port for injecting the aqueous electrolyte solution into the battery case 100.

[0034] A venting door for discharging gas generated inside the battery case 100 to the outside may be provided in the battery case 100. Here, the venting door may refer to a structure that opens or breaks to discharge the internal gas when the internal pressure exceeds a certain pressure.

[0035] A plurality of secondary batteries according to the present invention may be stacked in order from the front to the back and included in a battery module.

[0036] FIG. 2 is a perspective view of an electrode structure according to an embodiment of the present invention.

[0037] The electrode structure 200 may have a stack structure in which a first electrode, a second electrode, and a separator, each having a fixed area, are stacked in this order.

[0038] The electrode structure 200 may be connected to a first electrode portion and a second electrode portion formed on both sides thereof for electrical connection with an external device.

[0039] The first electrode portion may include a first electrode tab 310-1 and a first electrode lead 320-1. Here, the first electrode tab 310-1 may be electrically connected to each of the first electrode layers and extend from one end of the electrode structure 200. The first electrode lead 320-1 may be welded to the first electrode tab 310-1 and extend from one end of the first electrode tab 310-1.

[0040] The second electrode portion may include a second electrode tab 310-2 and a second electrode lead 320-2, where the second electrode tab 310-2 may be electrically connected to each of the second electrode layers and extend from the other end of the electrode structure 200. The second electrode lead 320-2 may be welded to the second electrode tab 310-2 and extend from the other end of the second electrode tab 310-2.

[0041] The first electrode tab 310-1 and the first electrode lead 320-1 may be welded in a linear shape, i.e., as shown in Fig. 2, the bead shape B formed by welding between the first electrode tab 310-1 and the first electrode lead 320-1 may be in a linear shape of a certain length.

[0042] In addition, the second electrode tab 310-2 and the second electrode lead 320-2 may be welded in a linear shape, i.e., as shown in Fig. 2, the bead shape B formed by welding between the second electrode tab 310-2 and the second electrode lead 320-2 may be in a linear shape of a certain length.

[0043] FIG. 3 is a perspective view of a battery case according to an embodiment of the present invention.

[0044] 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 joined to prevent leakage of the electrolyte contained therein.

[0045] The first case 110 and the second case 120 may be made of different materials, where the first case 110 may be made of an inflexible material and the second case 120 may be made of a flexible material.

[0046] For example, the first case 110 may be made of a hard metal (e.g., aluminum) and manufactured to maintain a specific shape, while the second case 120 may be made of a laminate sheet in which a resin layer and a metal layer (e.g., aluminum sheet) are laminated and bonded together, allowing for a certain degree of shape deformation.

[0047] 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 one or more of the top, front, and rear surfaces.

[0048] Here, the second case 120 may be sealed to the first case 110 while covering the open area of ​​the first case 110. For example, if a portion of the top and front surfaces of the first case 110 is open, the second case 120 may be sealed to the first case 110 while covering the open area of ​​the first case 110.

[0049] The second case 120 may be heat-sealed and bonded to the first case 110 by applying heat and pressure to an overlapping portion with the first case 110. For example, the second case 120 may be manufactured to have an area larger than the area of ​​the open region of the first case 110 and cover the open region. Here, the first case 110 and the second case 120 may be seal-bonded to each other by applying heat and pressure to an overlapping portion between the second case 120 and the first case 110.

[0050] FIG. 4 is a perspective view of a first case according to an embodiment of the present invention.

[0051] The first case 110 may be made of an inflexible material and may have at least a partial open area. For example, the first case 110 may be manufactured with a partial open area on each of the top, front, and back surfaces, as shown in FIG. 4.

[0052] The first case 110 may have a shape that surrounds (or encloses) the first electrode units 310-1 and 320-1 and the second electrode units 310-2 and 320-2. More specifically, the first case 110 may have a structure in which a central region A is open and both side regions have spaces formed therein, as shown in Fig. 4. As a result, when the electrode structure 200 is housed inside the first case 110, the first case 110 surrounds the first electrode units 310-1 and 320-1 and the second electrode units 310-2 and 320-2, thereby improving structural stability.

[0053] The open area A of the first case 110 may be formed such that the length (Wo) of the open width is equal to or greater than the length (We) of the electrode structure 200. More specifically, when the width (Wo) of the open area A of the first case 110 is equal to or greater than the width (We) of the electrode structure 200, the first case 110 surrounds the first electrode portion and the second electrode portion from both sides but does not surround the entire outer surface of the electrode structure 200, and the second case 120 covers the outer surface of the electrode structure 200 while covering the open area A. As a result, when a secondary battery is stacked with other secondary batteries to be manufactured as a module, pressure from the first cases of adjacent secondary batteries is not applied to both side ends of the electrode structure 200, and therefore, pressure variations in the electrode structure 200 are prevented.

[0054] FIG. 5 is a perspective view of a secondary battery including a battery case according to an embodiment of the present invention.

[0055] Referring to FIG. 5, the battery case may include a first case 110 and a second case 120.

[0056] The first case 110 may be made of an inflexible material and may have an open area on one or more of its top, front, and back surfaces, while the second case 120 may be made of a flexible material and may be sealed to the first case 110 while covering the open area of ​​the first case 110.

[0057] 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 airtightly penetrates. The first insulating member 111-1 may be made of an insulating material (e.g., insulating chemical-resistant plastic) and configured to be fixedly inserted into one side of the first case 110.

[0058] 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 passes airtightly. The second insulating member 111-2 may be made of an insulating material (e.g., insulating chemical-resistant plastic) and configured to be fixedly inserted into the other side of the first case 110.

[0059] The battery case 100 may be provided with venting doors 112-1 and 112-2 for discharging gas generated inside to the outside. Here, the venting doors may refer to structures that open or break to discharge internal gas when the internal pressure exceeds a certain pressure.

[0060] The venting door may be formed on one or more of the top, bottom, front, and rear surfaces of the first case 110. For example, the venting door may be provided at one end 112-1 of the top surface of the first case 110, or at the other end 112-2 of the top surface of the first case 110, as shown in FIG.

[0061] FIG. 6 is a front view of a secondary battery (without a second case joined) according to an embodiment of the present invention, and FIG. 7 is a vertical cross-sectional view of the secondary battery shown in FIG.

[0062] The first case 110 may be made of an inflexible material and may be manufactured with a top, front, and rear surface each having an open area, as shown in Fig. 6. Alternatively, the first case 110 may be made of a hard metal having a certain thickness, as shown in Fig. 7.

[0063] The first case 110 may have a shape that encloses (or surrounds) the first electrode units 310-1 and 320-1 and the second electrode units 310-2 and 320-2. More specifically, as shown in Fig. 7, both side ends of the first case 110 are formed in a U-shape to enclose the first electrode units 310-1 and 320-1 and the second electrode units 310-2 and 320-2.

[0064] The width (Wo) of the open area A of the first case 110 is formed to be equal to or greater than the width (We) of the electrode structure 200, and the first case 110 surrounds the first electrode units 310-1, 320-1 and the second electrode units 310-2, 320-2 at both ends, but does not cover the front, back, or top of the electrode structure 200. Here, the area of ​​the electrode structure 200 that is not covered by the first case 110 may be covered by the second case 120.

[0065] The first electrode lead 320-1 extends in one direction from one side end of the first electrode tab 310-1 and can airtightly pass through a through hole of the first insulating member 111-1 fixedly inserted into one side of the first case 110, and be exposed to the outside of the first case 110.

[0066] The second electrode lead 320-2 extends in the other direction from the other end of the second electrode tab 310-2, and can airtightly pass through the through hole of the second insulating member 111-2 fixedly inserted into the other side of the first case 110, and be exposed to the outside of the first case 110.

[0067] 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 shown in FIG. 8, and FIG. 10 is a bottom view of the secondary battery shown in FIG. 8.

[0068] The second case 120 is made of a flexible material and can be sealed and joined to the first case 110 while covering the open area of ​​the first case 110 .

[0069] When the first case 110 is manufactured with a shape in which some areas of the top, front, and back are open as shown in FIG. 6, the second case 120 can be sealed and joined to the first case 110 while covering the entire open area of ​​the first case 110 as shown in FIGS. 8 to 10.

[0070] Meanwhile, FIG. 10 shows a structure in which the second case 120 covers a portion of the bottom (lower surface) of the first case 110, but unlike what is shown in FIG. 10, the second case 120 can also be sealed and joined after surrounding the bottom surface of the first case 110.

[0071] The secondary batteries according to the various embodiments of the present invention described above have a prismatic cell structure at both ends and a pouch-type cell structure at the center, thereby exhibiting high structural stability and enabling weight reduction.

[0072] Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and variations of the present invention can be made without departing from the spirit and scope of the present invention as set forth in the following claims. [Explanation of symbols]

[0073] 100: Battery case 200: Electrode structure 110: First case 111: Insulating material 112: Venting door 120: Second case 310: Electrode tab 320: Electrode lead

Claims

1. an electrode structure including a first electrode, a second electrode, and a separator; and a battery case that houses the electrode structure therein and is sealed; The battery case is A secondary battery comprising a first case and a second case made of different materials.

2. the first case is made of a non-flexible material; The secondary battery according to claim 1 , wherein the second case is made of a flexible material.

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

4. The first case is At least some areas are open, The second case is The secondary battery according to claim 3 , wherein the second case is sealed and joined to the first case while covering the open area of ​​the first case.

5. The second case is The secondary battery according to claim 4 , wherein the battery is heat-sealed and joined to the first case by applying heat and pressure to an overlapping portion with the first case.

6. The first case is The secondary battery according to claim 4 or 5, which has a rectangular parallelepiped shape and has an open area formed on one or more of its top, front, and back surfaces.

7. The open area is The secondary battery according to claim 6 , wherein the open width is equal to or greater than the width of the electrode structure.

8. The first electrode portion 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 second electrode portion 6. The secondary battery according to claim 3, further 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. The first electrode lead includes: extending in one direction and penetrating one side surface of the first case; The second electrode lead includes: The secondary battery according to claim 8 , wherein the first case extends in the other direction and penetrates the other side surface of the first case.

10. The first case is a first insulating member fixedly inserted into one side surface of the first case, the first insulating member having a through hole through which the first electrode lead passes in an airtight manner; and The secondary battery according to claim 9 , further comprising: a second insulating member fixedly inserted into the other side surface of the first case, the second insulating member having a through hole formed therein through which the second electrode lead passes in an airtight manner.

11. The battery case further includes a vent door for discharging gas generated inside the battery case to the outside, The venting door is The secondary battery according to claim 3 , wherein the secondary battery is provided in a specific area of ​​the first case.

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