Secondary battery

Abstract

A secondary battery includes an electrode assembly including a first electrode substrate tab and a second electrode substrate tab, a case accommodating the electrode assembly, band-shaped terminals electrically connected to the first electrode substrate tab and the second electrode substrate tab, respectively, and extending to the outside of the case, and a conductive adhesive member at least partially surrounding a connection portion between the first electrode substrate tab and one of the band-shaped terminals and a connection portion between the second electrode substrate tab and the other of the band-shaped terminals, respectively.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2021-0131596, filed on October 5, 2021, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] An aspect of the embodiments of this disclosure relates to secondary batteries. Background Technology

[0004] The secondary battery includes an electrode assembly and a housing. The electrode assembly includes a positive electrode, a negative electrode, and a separator between the positive and negative electrodes. The housing contains an electrolyte solution immersed in the electrode assembly.

[0005] Based on the appearance and shape of the casing, secondary batteries can be classified into cylindrical, prismatic, and pouch-type. Pouch-type secondary batteries are constructed by winding or stacking electrode assemblies and sealing them together with the electrolyte within a pouch-shaped casing. After overlapping and soldering strip-shaped lead terminals to the substrate tabs of the electrode assemblies, insulating tape is attached and bent, exposing a portion of the lead terminals to the outside of the casing.

[0006] The aforementioned pouch-type secondary batteries require additional storage space because the substrate tabs and lead terminals are overlapped and welded to be bent and housed inside the pouch-shaped casing. Therefore, battery capacity cannot be increased, and the utilization rate of internal space may be reduced, which is problematic.

[0007] The information disclosed in this background section is provided to enhance the understanding of the background art of this disclosure, and therefore may contain information that does not constitute prior art. Summary of the Invention

[0008] According to an embodiment of the present disclosure, a secondary battery with improved internal space utilization is provided.

[0009] A secondary battery according to one or more embodiments of the present disclosure may include: an electrode assembly including a first electrode substrate terminal and a second electrode substrate terminal; a housing housing the electrode assembly; strip terminals electrically connected to the first electrode substrate terminal and the second electrode substrate terminal, respectively, and extending to the outside of the housing; and conductive adhesive members at least partially surrounding the connection portion between the first electrode substrate terminal and one of the strip terminals and the connection portion between the second electrode substrate terminal and the other of the strip terminals.

[0010] In the connection portion, the ends of the first electrode substrate connector and the second electrode substrate connector and the end portion of the strip terminal can be aligned with each other.

[0011] The conductive adhesive component can be attached to the bonding surfaces of the first electrode substrate terminal block and the second electrode substrate terminal block in their non-welded state, and to the end portion of the strip terminal.

[0012] The conductive adhesive component can be attached to the bonding surfaces of the first electrode substrate terminal block and the second electrode substrate terminal block in the soldered state, and to the end portion of the strip terminal.

[0013] At least one of the conductive adhesive components may include a base film layer with insulating properties and a conductive adhesive layer with conductive properties.

[0014] The conductive adhesive layer may include conductive powder and rubber-based adhesive.

[0015] The conductive adhesive layer may include a conductive mesh structure and a rubber-based adhesive.

[0016] The conductive adhesive layer may include an anisotropic conductive film (ACF).

[0017] The area of ​​the base film layer can be larger than the area of ​​the conductive adhesive layer.

[0018] The shell can be any one of the following: bag-shaped, cylindrical, or prismatic. Attached Figure Description

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

[0020] Figure 2 yes Figure 1 A view of the electrode assembly of a secondary battery.

[0021] Figure 3 It is shown Figure 2 An enlarged partial cross-sectional view of a portion of the electrode assembly.

[0022] Figure 4 yes Figure 3 The image shows an enlarged partial cross-sectional view of the connection portion between the substrate wiring tabs and the strip terminals.

[0023] Figure 5 It is shown Figure 3 An enlarged partial cross-sectional view of the electrode assembly being housed within the housing. Detailed Implementation

[0024] This document provides one or more exemplary embodiments of the present disclosure to explain the disclosure more fully to those skilled in the art, and the examples below can be modified in various other forms. However, the present disclosure can be implemented in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided to make the disclosure exhaustive and complete, and to convey various aspects and features of the disclosure to those skilled in the art.

[0025] Furthermore, in the accompanying drawings, the dimensions or thicknesses of various components may be exaggerated for simplicity and clarity. The same figures always indicate the same element. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Furthermore, it should be understood that when element A is referred to as being "connected to" element B, element A may be directly connected to element B, or one or more intermediate elements C may exist between element A and element B, such that element A and element B are indirectly connected to each other.

[0026] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be further understood that, when used in this specification, the terms “comprising” and / or “including” indicate the presence of the stated features, numbers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, numbers, steps, operations, elements, components, and / or groups thereof.

[0027] It should be understood that while the terms "first," "second," etc., may be used herein to describe various components, elements, regions, layers, and / or sections, these components, elements, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one component, element, region, layer, and / or section from other components, elements, regions, layers, and / or sections. Thus, for example, the first component, first element, first region, first layer, and / or first section discussed below may be referred to as a second component, second element, second region, second layer, and / or second section without departing from the teachings of this disclosure.

[0028] For ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” and “up” may be used herein to describe the relationship of one element or feature as illustrated in the figures to other elements or features. It should be understood that, in addition to the orientations depicted in the figures, spatial relative terms are intended to encompass different orientations of the device in use or operation. For example, if an element or feature in the figure is flipped, an element described as “below” or “under” other elements or features would then be oriented “above” or “upper” than the other elements or features. Therefore, the term “below” can encompass both above and below orientations.

[0029] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the inventive concept pertains. It should also be understood that terms defined in common dictionaries shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and are expressly defined herein, unless they are interpreted in an ideal or overly formal sense.

[0030] In this document, a secondary battery according to one or more embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings.

[0031] Figure 1 This is a perspective view of a secondary battery according to an embodiment of the present disclosure; Figure 2 yes Figure 1 A view of the electrode assembly of a secondary battery; and Figure 3 It is shown Figure 2 An enlarged partial cross-sectional view of a portion of the electrode assembly.

[0032] like Figure 1 and Figure 2 As shown, the secondary battery 10 according to an embodiment of the present disclosure may include an electrode assembly 100, a housing 300 for accommodating the electrode assembly 100, and a strip terminal 500 for electrically connecting the electrode assembly 100 to the outside of the secondary battery 10.

[0033] Electrode assembly 100 may include a first electrode plate 110 and a second electrode plate 130, which may be formed in a thin film or membrane shape, and a separator 120 insulating the first electrode plate 110 and the second electrode plate 130 from each other. In this document, the first electrode plate 110 may be a negative electrode, and the second electrode plate 130 may be a positive electrode, or vice versa. Each of the first electrode plate 110 and the second electrode plate 130 may include a substrate tab, and the electrode assembly 100 is connected to the outside of the secondary battery 10 via an electrical connection between the substrate tab and the strip terminal 500. Electrode assembly 100 may be formed in a jelly roll shape. In this disclosure, an example of the electrode assembly 100 being wound is described, but the embodiments are not limited thereto.

[0034] In one embodiment, the first electrode plate 110, which is the negative electrode, can be formed by coating a first electrode active material 114 (such as graphite or carbon) onto a first electrode current collector 112 formed of a metal foil (such as copper, copper alloy, nickel, or nickel alloy). A first electrode uncoated region 116, to which the first electrode active material 114 is not coated, can be formed in a portion of the first electrode current collector 112. A plurality of first electrode substrate tabs 118 can be formed on the first electrode uncoated region 116. For example, the first electrode substrate tabs 118 can be formed into a certain shape by pressing the first electrode uncoated region 116 using a press. As an example, the first electrode substrate tabs 118 can have a rectangular shape. The first electrode substrate tabs 118 can extend to the outside of the first electrode current collector 112 (e.g., based on...). Figure 2 (Extending upwards). Furthermore, the first electrode substrate terminal block 118 can be formed so as not to overlap with the second electrode substrate terminal block 138. For example, it is provided with... Figure 2 All substrate terminals on the left side of the electrode assembly 100 can be first electrode substrate terminals 118. The first electrode substrate terminals 118 can be configured to be spaced apart from the second electrode substrate terminals 138. The first electrode substrate terminals 118 serve as channels for current to flow between the first electrode plate 110 and the strip terminal 500.

[0035] A separator 120 located between the first electrode plate 110 and the second electrode plate 130 prevents or substantially prevents short circuits between the first electrode plate 110 and the second electrode plate 130, and allows lithium ions to move. For this purpose, the separator 120 can be formed to be larger than the first electrode plate 110 and the second electrode plate 130. The separator 120 can be made of polyethylene, polypropylene, or a composite film of polyethylene and polypropylene, but is not limited thereto.

[0036] In one embodiment, the second electrode plate 130, which is the positive electrode, can be formed by coating a second electrode active material 134 (such as a transition metal oxide) onto a second electrode current collector 132 formed of a metal foil (such as aluminum or an aluminum alloy). Uncoated areas 136 of the second electrode, to which the second electrode active material 134 is not coated, can be formed in a portion of the second electrode current collector 132. A plurality of second electrode substrate tabs 138 can be formed on the uncoated areas 136. For example, the second electrode substrate tabs 138 can be formed into a specific shape by pressing the uncoated areas 136 using a press. As an example, the second electrode substrate tabs 138 can have a rectangular shape. The second electrode substrate tabs 138 can extend to the outside of the second electrode current collector 132 (e.g., based on...). Figure 2(Extending upwards). Furthermore, the second electrode substrate terminal block 138 can be formed so as not to overlap with the first electrode substrate terminal block 118. For example, it is provided with... Figure 2 All substrate terminals on the right side of the electrode assembly 100 can be second electrode substrate terminals 138. The second electrode substrate terminals 138 can be configured to be spaced apart from the first electrode substrate terminals 118. The second electrode substrate terminals 138 serve as channels for current flow between the second electrode plate 130 and the strip terminal 500.

[0037] like Figure 3 As shown, the strip terminal 500 is used to electrically connect the exterior of the secondary battery 10 to the substrate terminals 118 and 138. The strip terminals 500 can be provided in pairs to be electrically connected to the first electrode substrate terminal 118 and the second electrode substrate terminal 138, respectively. In this document, the first electrode substrate terminal 118 and the second electrode substrate terminal 138 can be collected in the same or different directions and then electrically connected to the strip terminal 500, respectively. In one embodiment, the strip terminal 500 can be in the form of a thin film or membrane and may include an insulating portion 510 to insulate the strip terminal 500 from the housing 300. The insulating portion 510 can be formed in the area in contact with the housing 300. In one embodiment, the strip terminal 500 can be formed to have the same width as the substrate terminals 118 and 138 (see [link to documentation]). Figure 1 However, this is not the only possibility. For example, the strip terminal 500 can be electrically connected to the first electrode substrate terminal piece 118 and the second electrode substrate terminal piece 138 via an adhesive member 700 (which will be described later).

[0038] The electrode assembly 100 having the above structure is housed together with the electrolyte in the housing 300.

[0039] like Figure 1 As shown, housing 300 may include a housing space in which electrode assembly 100 can be housed.

[0040] The housing 300 may be referred to as a laminated outer material, a bag, a bag-shaped outer material, a bag-shaped housing, etc. After bending the plate-shaped outer material so that the bent portions face each other, the housing 300 can form a recess 310 by pressing or stretching its surface. The electrode assembly 100 is accommodated in the recess 310. A sealing portion 330 is formed at the outer periphery of the recess 310, and the sealing portion 330 can be sealed by heat sealing or the like while the electrode assembly 100 is accommodated in the recess 310. In this disclosure, the bag-type secondary battery 10 has been described by way of example, but the terminal connection structure described later can also be applied to cylindrical or prismatic secondary batteries.

[0041] In this paper, the connection structure between the substrate tab and the strip terminal will be described in more detail. For convenience, the side surface of the first electrode substrate tab will be illustrated and described, but the same structure can also be applied to the second electrode substrate tab.

[0042] Figure 4 yes Figure 3 An enlarged partial cross-sectional view of the connection portion between the substrate wiring tabs and the strip terminals is shown; and Figure 5 It is shown Figure 3 An enlarged partial cross-sectional view of the electrode assembly being housed within the housing.

[0043] In such Figure 2 After the first electrode substrate tab 118 shown is collected and soldered in the direction of the electrode assembly 100, the ends of the first electrode substrate tab 118 can be aligned to contact the ends of the strip terminal 500, such as... Figure 4 and Figure 5 As shown in the figures, after the ends of the first electrode substrate tab 118 and the strip terminal 500 are butt-aligned, an adhesive member (e.g., a conductive adhesive member) 700 is attached to electrically connect the first electrode substrate tab 118 and the strip terminal 500 to each other. In one embodiment, the adhesive member 700 may be attached to the mating surface of the butt-aligned first electrode substrate tab 118 and the end of the strip terminal 500 in a non-soldered state. In another embodiment, the adhesive member 700 may be attached with the mating surface of the butt-aligned first electrode substrate tab 118 and the end of the strip terminal 500 soldered. In the figures, the distance between the substrate tab 118 and the conductive adhesive member 700 is shown to indicate a thickness difference. However, in reality, the substrate tab and the conductive adhesive member are in close contact.

[0044] like Figure 4 As shown, in one embodiment, the adhesive member 700 may include a base film layer 710 as an outer layer and a conductive adhesive layer 720 as an inner layer. The base film layer 710 is a layer disposed on the outside of the connection portion between the first electrode substrate tab 118 and the strip terminal 500. The base film layer 710 may be made of an insulating material (such as polyimide (PI) or polyethylene terephthalate (PET)). For example, the base film layer 710 may have an area larger than that of the conductive adhesive layer 720.

[0045] The conductive adhesive layer 720 is a layer that contacts the first electrode substrate tab 118 and the strip terminal 500, and can be made of a conductive adhesive material. In one embodiment, the conductive adhesive layer 720 can be made by mixing conductive powder with an adhesive, or it can be formed such that the conductive material forms a mesh structure within the adhesive layer. In one embodiment, the adhesive component of the conductive adhesive layer 720 can be, for example, a rubber-based adhesive. In another embodiment, the conductive adhesive layer 720 can include an anisotropic conductive film (ACF).

[0046] like Figure 4 As shown, the adhesive member 700 can be attached such that the conductive adhesive layer 720 contacts the upper and lower surfaces of the connection portion between the first electrode substrate tab 118 and the strip terminal 500. Since the first electrode substrate tab 118 and the strip terminal 500 are electrically connected to each other via the conductive adhesive layer 720, they can be electrically connected without overlapping and welding. Therefore, compared to the conventional structure where the first electrode substrate tab and the strip terminal are overlapped and welded before a covering strip is attached, the thickness of the connection portion between the first electrode substrate tab 118 and the strip terminal 500 according to this disclosure can be significantly reduced.

[0047] After the first electrode substrate connector 118 and the strip terminal 500 are connected using the adhesive member 700, the first electrode substrate connector 118 can be bent to be accommodated in the recess 310 of the housing 300, and then the housing 300 is sealed.

[0048] According to embodiments of this disclosure, since the thickness of the connection portion between the first electrode substrate tab 118 and the strip terminal 500 is reduced, the space occupied inside the housing 300 can also be reduced after bending the first electrode substrate tab 118 compared to a conventional structure. Therefore, the capacity of the electrode assembly 100 can be increased by the space gained due to the reduced thickness, and the size of the housing 300 can be reduced.

[0049] As described above, according to one or more embodiments, the thickness of the connection portion between the substrate tab and the strip terminal can be reduced, thereby reducing the space occupied by the connection portion inside the battery casing after bending, thus improving the utilization of space inside the battery. Furthermore, due to the reduced thickness of the connection portion, the battery capacity can be increased.

[0050] While one or more embodiments have been described herein, this disclosure is not limited thereto, and those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of this disclosure as set forth in the appended claims.

Claims

1. A secondary battery, comprising: An electrode assembly, including a first electrode substrate connector and a second electrode substrate connector; Housing that houses the electrode assembly; Strip terminals are electrically connected to the first electrode substrate terminal block and the second electrode substrate terminal block, respectively, and extend to the outside of the housing; as well as The conductive adhesive member at least partially surrounds the connection portion between the first electrode substrate tab and one of the strip terminals, and the connection portion between the second electrode substrate tab and the other of the strip terminals. The conductive adhesive component comprises a conductive adhesive material and is attached to a bonding surface perpendicular to the plane containing the ends of the first electrode substrate tab and the second electrode substrate tab, and to the end portion of the strip terminal, wherein the ends of the first electrode substrate tab and the second electrode substrate tab and the end portion of the strip terminal are in contact with each other.

2. The secondary battery according to claim 1, wherein in the connection portion, the ends of the first electrode substrate tab and the second electrode substrate tab and the end portions of the strip terminal are aligned and mated with each other.

3. The secondary battery according to claim 2, wherein the conductive adhesive member is attached to the bonding surface of the first electrode substrate terminal block and the second electrode substrate terminal block in a non-welded state and the end portion of the strip terminal.

4. The secondary battery according to claim 2, wherein the conductive adhesive member is attached to the bonding surface of each of the first electrode substrate tab and the second electrode substrate tab in a welded state and the end portion of the strip terminal.

5. The secondary battery according to claim 1, wherein at least one of the conductive adhesive components comprises a base film layer having insulating properties and a conductive adhesive layer comprising the adhesive material having conductive properties.

6. The secondary battery according to claim 5, wherein the conductive adhesive layer comprises conductive powder and rubber-based adhesive.

7. The secondary battery according to claim 5, wherein the conductive adhesive layer comprises a conductive mesh structure and a rubber-based adhesive.

8. The secondary battery according to claim 5, wherein the conductive adhesive layer comprises an anisotropic conductive film.

9. The secondary battery according to claim 5, wherein the area of ​​the base film layer is larger than the area of ​​the conductive adhesive layer.

10. The secondary battery according to claim 1, wherein the casing is any one of pouch type, cylindrical type and prismatic type.

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