Secondary battery

Abstract

The present invention relates to a secondary battery, comprising: a first electrode assembly equipped with a first terminal tab and a second terminal tab; a second electrode assembly electrically connected to the first electrode assembly; a plurality of connecting terminals, which are arranged between and connected to the first electrode assembly and the second electrode assembly, and electrically connect the first electrode assembly and the second electrode assembly; and a shell, which is equipped with a accommodating portion which is open on one side thereof and has an accommodating space to accommodate the first electrode assembly and the second electrode assembly and an electrolyte, and a cover which is connected to the open side of the accommodating portion and covers the open side of the accommodating portion, wherein when the shell is folded, the shell is folded so that one side and the other side of the outer surface of the cover are brought together.

Description

Technical Field

[0001] Various embodiments of the present invention relate to secondary batteries. Background Art

[0002] Generally speaking, electronic devices, such as notebook computers, mini notebook computers, e-books, mobile computers, ultra mobile personal computers (UMPCs), or portable multimedia players (PMPs), use a battery pack as a portable power source, and the battery pack may have a plurality of battery cells connected in series and / or in parallel. The battery pack may include a protection circuit module (PCM) for protecting the battery cells from overcharge, overdischarge, or overcurrent, and the secondary battery and the protection circuit module may be housed together in a housing.

[0003] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not constitute the prior art. Summary of the invention

[0004] Technical issues

[0005] The present invention provides a secondary battery in which an electrode assembly is formed to be foldable by providing a connection structure for connecting two electrode assemblies in parallel or in series in one case.

[0006] Solution to the problem

[0007] A secondary battery according to the present invention includes: a first electrode assembly equipped with a first terminal tab and a second terminal tab; a second electrode assembly electrically connected to the first electrode assembly; a plurality of connecting terminals, which are arranged between and connected to the first electrode assembly and the second electrode assembly, and electrically connect the first electrode assembly and the second electrode assembly; and a shell, which is equipped with a accommodating portion which is open on one side thereof and has an accommodating space to accommodate the first electrode assembly and the second electrode assembly and an electrolyte, and a cover connected to one side of the opening of the accommodating portion and covering the one side of the opening of the accommodating portion, wherein when the shell is folded, the shell is folded so that one side and the other side of the outer surface of the cover are brought together.

[0008] When the housing is folded, the folded portions of the cover may be in close contact with each other.

[0009] The case may further include a coupling portion extending along an edge of one side of the opening of the accommodating portion so as to extend parallel to the cover to be coupled thereto.

[0010] When the case is folded, the coupling portion and the cover may have a cutout groove formed by cutting an end portion corresponding to the folded portion.

[0011] Each of the first and second electrode assemblies may include a first electrode plate, a second electrode plate, and a separator interposed between the first and second electrode plates, and the first electrode assembly may further include first and second tabs electrically connected to the first and second electrode plates, respectively.

[0012] The first electrode plate may be a positive electrode plate having an aluminum substrate, the second electrode plate may be a negative electrode plate having a copper substrate, and the connection tabs may include a positive electrode connection tab and a negative electrode connection tab electrically connected to the first and second electrode plates, respectively.

[0013] The positive electrode connection tab of the first electrode assembly may include a substrate contact portion connected to the aluminum substrate and a connection portion integrally formed with the substrate contact portion and exposed to one side of the first electrode assembly, and the negative electrode connection tab of the first electrode assembly may include a substrate contact portion connected to the copper substrate and a connection portion integrally formed with the substrate contact portion and exposed to one side of the first electrode assembly. The positive electrode connection tab of the second electrode assembly may include a substrate contact portion connected to the aluminum substrate and a connection portion integrally formed with the substrate contact portion and exposed to the first electrode assembly, and the negative electrode connection tab of the second electrode assembly may include a substrate contact portion connected to the copper substrate and a connection portion integrally formed with the substrate contact portion and exposed to the first electrode assembly.

[0014] The positive electrode connection tab may include one or two positive electrode connection tabs, and the negative electrode connection tab may include one or two negative electrode connection tabs, respectively.

[0015] The connection tab connected to the first electrode assembly and the connection tab connected to the second electrode assembly may overlap each other.

[0016] The connection tab connected to the first electrode assembly and the connection tab connected to the second electrode assembly may be disposed to have a step difference from each other.

[0017] Insulating tapes may be attached to coupling portions of the connection tab connected to the first electrode assembly and the connection tab connected to the second electrode assembly.

[0018] The first electrode assembly and the second electrode assembly may be connected to each other in parallel.

[0019] The first electrode assembly and the second electrode assembly may be connected to each other in series, and the accommodation space may be divided into two to accommodate the first electrode assembly and the second electrode assembly, respectively, so that the electrolyte of the first electrode assembly and the electrolyte of the second electrode assembly are not communicated with each other.

[0020] Advantageous Effects of the Present Disclosure

[0021] In the secondary battery according to the embodiment of the present invention, two electrode assemblies are connected in parallel or in series with each other in one housing, and each electrode assembly is connected to be foldable by using a common terminal tab or a substrate terminal tab. Therefore, the folding of the secondary battery is ensured, and the durability of the folded portion can be ensured.

[0022] That is, the embodiment of the present invention provides a secondary battery formed to be foldable by providing a connection structure for connecting two electrode assemblies in parallel or in series with each other in one case. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. 1 is a combined perspective view showing a folded state of a secondary battery according to an embodiment of the present invention.

[0024] Figure 2 To show Figure 1 A combined perspective view of a secondary battery in an unfolded state.

[0025] Figure 3 for Figure 2 An exploded perspective view of a secondary battery.

[0026] Figure 4 To show Figure 3 A plan view of an electrode assembly of a secondary battery is shown.

[0027] Figure 5 To show Figure 4 A plan view showing the connected state of the electrode assembly.

[0028] Figure 6 and Figure 7 1 and 2 are plan views showing various types of electrode assemblies according to the present invention.

[0029] FIG. 8A to FIG. 10C 2 are cross-sectional views illustrating various connection forms and a folding process of an electrode assembly according to an embodiment of the present invention.

[0030] Fig.11 is a plan view showing an electrode assembly of a secondary battery according to another embodiment of the present invention.

[0031] Fig. 12A 12C are cross-sectional views illustrating various connection forms and a folding process of an electrode assembly according to another embodiment of the present invention. DETAILED DESCRIPTION

[0032] Hereinafter, exemplary embodiments of the present invention will be described in detail.

[0033] However, the embodiments of the present invention can be implemented in many different forms and should not be interpreted as limited to the example (or exemplary) embodiments set forth herein. Rather, these example embodiments are provided to make this disclosure thorough and complete and to convey aspects and features of the present invention to those skilled in the art.

[0034] In addition, in the accompanying drawings, the size or thickness of various components is exaggerated for brevity and clarity. The same reference numerals refer to the same elements throughout. As used herein, the term "and / or" includes any and all combinations of one or more related enumerated items. In addition, it will 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 there may be an intervening element C therebetween, such that element A and element B are indirectly connected to each other.

[0035] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the present disclosure. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. It will be further understood that when used in this specification, the terms "comprise" and / or "include" specify the features, numbers, steps, operations, elements and / or components that are described, but do not exclude the presence or addition of one or more other features, numbers, steps, operations, elements, components and / or combinations thereof.

[0036] It will be understood that although the terms first, second, etc. may be used herein to describe various members, elements, regions, layers, and / or parts, these members, elements, regions, layers, and / or parts should not be limited by these terms. These terms are only used to distinguish one member, element, region, layer, and / or part from another member, element, region, layer, and / or part. Therefore, for example, without departing from the teachings of the present invention, the first member, first element, first region, first layer, and / or first part discussed below may be referred to as the second member, second element, second region, second layer, and / or second part.

[0037] For ease of description, spatially relative terms, such as "below," "below," "below," "above," "on," etc., may be used herein to describe the relationship of one element or feature shown in the drawings to another element(s) or feature(s). It will be understood that the spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the drawings. For example, if the elements or features in the drawings are flipped, the elements described as "below" or "beneath" other elements or features will be oriented as "on" or "above" other elements or features. Thus, the exemplary term "below" may encompass both above and below orientations.

[0038] In describing the main features of the present invention, for convenience, reference is made to Figure 1 , the upper side is defined as the upward direction, and the lower side is defined as the downward direction. In addition, refer to Figure 1 , the long side direction of the shell is defined as the longitudinal direction, the short side direction of the shell is defined as the width direction, the direction toward the outside of the shell is defined as the outward direction, and the direction toward the accommodation space of the shell is defined as the inward direction. Therefore, the connection relationship of various components includes all concepts that may change accordingly when such arrangement direction changes.

[0039] Figure 1 FIG. 1 is a combined perspective view showing a folded state of a secondary battery according to an embodiment of the present invention. Figure 2 To show Figure 1 A combined perspective view of a secondary battery in an unfolded state. Figure 3 for Figure 2 An exploded perspective view of a secondary battery. Figure 4 To show Figure 3 A plan view of an electrode assembly of a secondary battery is shown. Figure 5 To show Figure 4 A plan view showing the connected state of the electrode assembly. Figure 6 and Figure 7 1 and 2 are plan views showing various types of electrode assemblies according to the present invention.

[0040] like Figures 1 to 3 As shown, the secondary battery 10 according to the embodiment of the present invention includes two electrode assemblies 100 and 200, a case 300 for accommodating the electrode assemblies 100 and 200 and an electrolyte, and a connection tab 400 connecting the two electrode assemblies 100 and 200 to each other. Either of the two electrode assemblies 100 and 200 includes a first tab 140 and a second tab 150 respectively pulled out from the electrode assemblies 100 and 200. An insulating tape 500 may be attached to the first tab 140, the second tab 150, and the connection tab 400.

[0041] For convenience, one of the electrode assemblies 100 and 200 provided with the first and second tabs 140 and 150 is defined as a first electrode assembly 100 , and the other is defined as a second electrode assembly 200 .

[0042] like Figure 1 and Figures 3 to 5 As shown, the first electrode assembly 100 may be formed by winding a unit laminate including a first electrode plate 110, a second electrode plate 120, and a separator 130 that physically separates the first electrode plate 110 and the second electrode plate 120 from each other, or by laminating a plurality of layers. The first tab 140 and the second tab 150 may be electrically connected to either of the first electrode plate 110 and the second electrode plate 120, respectively.

[0043] The first electrode plate 110 may be a positive electrode plate made of a mixture including an aluminum substrate and an active material. The second electrode plate 120 may be a negative electrode plate made of a mixture including a copper substrate and an active material. However, the first electrode plate 110 may be a negative electrode plate, and the second electrode plate 120 may be a positive electrode plate. The separator 130 may include a plurality of separators, which are respectively inserted between the plurality of first electrode plates 110 and the plurality of second electrode plates 120. The separator 130 is an insulator that prevents a short circuit between the first electrode plate 110 and the second electrode plate 120.

[0044] The first terminal tab 140 is electrically connected to the first electrode plate 110, and the second terminal tab 150 is electrically connected to the second electrode plate 120. One end of each of the first terminal tab 140 and the second terminal tab 150 partially protrudes to the outside of the first electrode plate 110 and the second electrode plate 120 to electrically connect the electrode assemblies 100 and 200 to the outside. When the first electrode plate 110 is a positive electrode plate, the first terminal tab 140 may become a positive electrode terminal tab, and when the second electrode plate 120 is a negative electrode plate, the second terminal tab 150 may become a negative electrode terminal tab. The first terminal tab 140 and the second terminal tab 150 are spaced apart from each other by a predetermined distance and are pulled out in the same direction.

[0045] In the first terminal tab 140 and the second terminal tab 150, the insulating tape 500 may be attached to a portion serving as a boundary drawn from the housing 300, or to one inner surface (surface not contacting the first electrode plate and the second electrode plate) including the boundary portion. The insulating tape 500 prevents a short circuit between the first terminal tab 140 and the second terminal tab 150.

[0046] like Figure 1 and Figures 3 to 5 As shown, the second electrode assembly 200 is connected in parallel with the first electrode assembly 100 through a connecting tab 400, which will be described later. Similar to the first electrode assembly 100, the second electrode assembly 200 includes a first electrode plate 210, a second electrode plate 220, and a separator 230 in addition to the first and second tabs 140 and 150. The second electrode assembly 200 may be formed to have the same size and capacity as the first electrode assembly 100, or may be formed to have a size and capacity different from the first electrode assembly 100 (see Figure 6 and Figure 7 ).

[0047] like Figure 5 As shown, when the first electrode assembly 100 and the second electrode assembly 200 have the same size and capacity, the connection tab 400 may be disposed at the center of the first electrode assembly 100 and the second electrode assembly 200. Figure 6As shown, when the size and capacity of the first electrode assembly 100 are larger than the size and capacity of the second electrode assembly 200, the connection tab 400 may be disposed at one side of the first electrode assembly 100 and at the center of the second electrode assembly 200. Figure 7 As shown, when the size and capacity of the second electrode assembly 200 are greater than those of the first electrode assembly 100 , the connection tab 400 may be disposed at one side of the second electrode assembly 200 and at the center of the first electrode assembly 100 .

[0048] The first electrode assembly 100 and the second electrode assembly 200 are accommodated in the case 300 while being connected to the connection tab 400 .

[0049] like Figures 1 to 3 As shown, the housing 300 may include a housing portion 310 forming a housing space 310a and a cover 320 covering one surface of the housing portion 310. The housing 300 accommodates the first electrode assembly 100 and the second electrode assembly 200 and the electrolyte. In a state where the first electrode assembly 100 and the second electrode assembly 200 are accommodated in the housing 300, the housing 300 is welded to the cover 320 and sealed by the cover 320. The housing 300 is folded so that one side of the cover 320 contacts the other side surface.

[0050] The receiving portion 310 may have a box shape in which one side thereof is opened to form a receiving space 310a. The receiving space 310a has a size and shape corresponding to the size and shape of the first electrode assembly 100 and the second electrode assembly 200. A coupling portion 312 extending vertically outward from an end of the receiving portion 310 is formed along an edge of one side of the opening of the receiving portion 310.

[0051] The coupling portion 312 is a portion coupled to the cover 320 by various methods such as fusion or adhesion. When the receiving portion 310 is folded, a cutout groove 330 is formed in the coupling portion 312 to correspond to the position of the folded portion.

[0052] The cutout groove 330 is a groove having a semicircular or 'V' shape, and is formed by cutting a portion of the end of the coupling portion 312. When the housing 300 is folded in half, the thickness of the folded portion of the coupling portion 312 and the cover 320 may increase, so wrinkles or bulges may appear. If the folded portion bulges or wrinkles, the housing 300 may not be completely folded, and the folded state may be released. Therefore, in order to prevent this problem, the cutout groove 330 is formed in the coupling portion 312, corresponding to the portion where the housing 300 is folded.

[0053] The shape of the cutout groove 330 is not limited to the above-described semicircular or 'V' shape as long as the folded portion of the housing 300 can be smoothly folded.

[0054] Since the cover 320 covers the opening side of the receiving part 310, the cover 320 has a rectangular plate shape corresponding to the size and shape of the receiving part 310 and the coupling part 312. The edge of the cover 320 is coupled to the coupling part 312, thereby fixing the receiving part 310 and the cover 320.

[0055] When the housing 300 is folded in half, the cover 320 is folded together with the accommodating portion 310. Therefore, the cutout groove 330 has the same shape as when the cutout groove 330 is formed on the cover 320 at the end position of the housing 300 where the cutout groove 330 is formed.

[0056] When the housing 300 is folded in half, the cover 320 may have one end and the other end of the outer surface in close contact with each other, and the folded portions may also be in close contact with each other.

[0057] As described above, when the case 300 is completely folded in half, in order to stably maintain the electrical connection state between the first electrode assembly 100 and the second electrode assembly 200 , the flexible connection tab 400 is basically required.

[0058] like Figure 1 , Figure 4 and Figure 5 As shown, the connection tab 400 is disposed between the first electrode assembly 100 and the second electrode assembly 200. The connection tabs 400 are provided in the first electrode assembly 100 and the second electrode assembly 200, respectively, and consist of a double tab of a positive electrode connection tab 400 and a negative electrode connection tab 400. That is, each of the first electrode assembly 100 and the second electrode assembly 200 includes a pair of connection tabs 400.

[0059] The positive electrode connection tab 400 is electrically connected to the aluminum substrate provided on the first electrode plate 110 of each of the first and second electrode assemblies 100 and 200. The negative electrode connection tab 400 is electrically connected to the copper substrate provided on the second electrode plate 120 of each of the first and second electrode assemblies 100 and 200.

[0060] In addition, if FIG. 10A to FIG. 1 As shown in FIG. 0D, each of the positive electrode connection tab 400 and the negative electrode connection tab 400 may be provided one by one (hereinafter, a single tab structure), and as shown in FIG. 8A to 9D As shown, each of the positive electrode connection tab 400 and the negative electrode connection tab 400 may be provided in pairs (hereinafter, double tab structure). When the positive electrode connection tab 400 and the negative electrode connection tab 400 are provided in pairs, a total of eight connection tabs 400 are disposed between the two electrode assemblies.

[0061] Each of the connection tabs 400 includes a substrate contact portion 410 electrically connected to the inner substrate of the first electrode assembly 100 or the second electrode assembly 200, and a connection portion 420 exposed to the outside of the first electrode assembly 100 or the second electrode assembly 200. However, the substrate contact portion 410 and the connection portion 420 are not separately formed, and one connection tab 400 is defined by dividing the substrate contact portion 410 and the connection portion 420 according to positions.

[0062] like Figure 5 As shown, the substrate contact portion 410 is inserted into the first electrode plate 110 or the second electrode plate 120 to make surface contact with the aluminum substrate or the copper substrate to be electrically connected. That is, the substrate contact portion 410 of the positive electrode connection terminal tab 400 is electrically connected to the aluminum substrate, and the substrate contact portion 410 of the negative electrode connection terminal tab 400 is electrically connected to the copper substrate. The positive electrode connection terminal tab 400 is arranged in a straight line with the first terminal tab 140 as the positive electrode terminal tab, and the negative electrode connection terminal tab 400 is arranged in a straight line with the second terminal tab 150 as the negative electrode terminal tab, so the first electrode assembly 100 and the second electrode assembly 200 are connected in parallel. The connection portion 420 formed integrally with the substrate contact portion 410 is exposed to the outside of the first electrode assembly 100 and the second electrode assembly 200.

[0063] The connection portion 420 is exposed to be disposed between the first electrode assembly 100 and the second electrode assembly 200. That is, the connection tabs 400 respectively connected to the first electrode assembly 100 and the second electrode assembly 200 are disposed so that the connection portions 420 face each other. The connection portions 420 of the connection tabs 400 facing each other may overlap each other by a predetermined portion and be coupled to each other.

[0064] The connection part 420 is connected by a method such as welding to ensure electrical connection. The insulating tape 500 may be attached to the connection part 420 to prevent a short circuit between the connection part 420 and its periphery. The insulating tape 500 may be attached to cover a larger area than the welding part. In addition, the insulating tape 500 may not be attached to the connection part 420, but when the connection parts 420 are connected to each other in a state where the insulator is pre-attached to the connection part 420, the insulators may be connected together.

[0065] When the secondary battery 10 is folded, the connection tab 400 is folded around the point on each connection portion 420 to which the insulating tape 500 is not attached (see FIG. 1 ). Figure 5 Attachment of the insulating tape 500 may be selectively applied.

[0066] The connection tab 400 may have a smaller thickness than the first and second tabs 140 and 150 described above to allow the rechargeable battery 10 to be easily folded around the connection portion 420. Therefore, the folded portion may be flexibly bent while maintaining electrical connection between the two electrode assemblies without increasing the thickness of the folded portion.

[0067] Hereinafter, a coupling state between the connection tabs 400 of the first electrode assembly 100 and the second electrode assembly 200 will be described in detail (for convenience, the connection tab of the second electrode assembly is defined as 420a to be distinguished from the connection tab of the first electrode assembly).

[0068] FIG. 8A to FIG. 10C 2 are cross-sectional views illustrating various connection forms and a folding process of an electrode assembly according to an embodiment of the present invention.

[0069] like Figures 8A to 8D As shown, the secondary battery 10 according to the embodiment of the present invention may include an insulating tape 500 or a connection tab 400 having a double tab structure in which no insulator is provided (for convenience, only the positive electrode connection tab is shown in the drawing).

[0070] The connection portions 420 and 420a of the connection tab 400 are formed to have a sufficient length to maintain the electrical connection between the first electrode assembly 100 and the second electrode assembly 200 when the secondary battery 10 is folded (see FIG. 1 ). Fig.8D ). Since the cover 320 is located between the first electrode assembly 100 and the second electrode assembly 200 when the secondary battery 10 is folded, the length of the connection tab 400 is preferably formed in consideration of this.

[0071] In addition, since the connection portion 420 provided in the first electrode assembly 100 and the connection portion 420a provided in the second electrode assembly 200 should overlap each other and then be welded to each other, based on Fig. 8A , the upper connection portion 420, 420a is formed to be longer than the lower connection portion.

[0072] The longer connecting portions 420, 420a are bent to be in close contact with the lower connecting portion 420 (see Figure 8B ), and the opposing connecting portions 420 and 420a are welded to each other to fix the two connecting portions 420 and 420a to each other (see Figure 8C ). Here, if the heights of the connection portions 420 and 420a are the same, the welding portion may be curved, and thus the positive electrode connection tab 400 of the second electrode assembly 200 may be formed to have a step height relative to the positive electrode connection tab 400 of the first electrode assembly 100. Therefore, after welding, the lower surface of the welding region to which the two connection portions 420 and 420a are welded may remain horizontal without curling or bending.

[0073] In addition, if 9A to 9D As shown, the secondary battery 10 according to the embodiment of the present invention may include an insulating tape 500 or a connection tab 400 having a double tab structure provided with an insulator (for convenience, only a positive electrode connection tab is shown in the drawing).

[0074] In this case, the connecting tab 400 may be connected with FIG. 8A to FIG. 8D The same structure as shown is coupled, an insulating tape 500 may be attached to the bonding portion, or the insulators may be bonded to each other.

[0075] In addition, if FIG. 10A to FIG. 10C As shown, the secondary battery 10 according to the embodiment of the present invention may include an insulating tape 500 or a connection tab 400 having a single tab structure in which no insulator is provided (for convenience, only a positive electrode connection tab is shown in the drawing).

[0076] In this case, in FIG. 8A to FIG. 8D In the same structure as shown, the opposing connection tabs 400 may be provided with a step difference from each other, and an insulating tape 500 may be attached to a bonding portion of the single tab structure, or insulators may be bonded to each other (not shown).

[0077] In the above embodiment, the connection tab 400 having a thickness less than the first tab 140 and the second tab 150 has been described. Hereinafter, a secondary battery 10 according to another embodiment of the present invention will be described (the same components as those in the above embodiment use the same reference numerals, but detailed description of overlapping features will be omitted).

[0078] Fig.11 is a plan view showing an electrode assembly of a secondary battery according to another embodiment of the present invention. FIG. 12A to FIG. 12C 2 is a cross-sectional view illustrating various connection forms and a folding process of an electrode assembly according to another embodiment of the present invention.

[0079] like Fig.11 As shown, a secondary battery 10' according to another embodiment of the present invention has the same structure as the secondary battery 10 of the above embodiment, but the first electrode assembly 100' and the second electrode assembly 200' may be electrically connected by using a first tab 140' and a second tab 150' instead of a thin connection tab.

[0080] Here, the first and second tabs 140' and 150' provided in the first electrode assembly 100' extend from one end to the other end of the first electrode assembly 100' so that they are partially exposed to the other end of the first electrode assembly 100'. Although the connection tab 400' is formed at the second electrode assembly 200', the connection tab 400' is a common electrode tab that is the same as the first and second tabs 140' and 150', and is disposed to have a step height relative to the first and second tabs 140' and 150'. The connection tab 400' may be electrically connected to the first and second tabs 140' and 150' by a bonding method such as welding.

[0081] like FIG. 12A to FIG. 12C As shown, in a secondary battery 10' according to another embodiment of the present invention, the connection tab 400' is formed to have the same thickness as the first tab 140' and the second tab 150'. FIG. 12A to FIG. 12C The connecting lug 400' is based on FIG. 8A to FIG. 10C The connection tab 400 of the embodiment is thick, but the connection tab 400' itself has high rigidity and thus may not bend. Therefore, if the connection tab 400' has a sufficient length, folding of the secondary battery 10' may be achieved.

[0082] In the above embodiment, as an example, it has been described that the first electrode assembly and the second electrode assembly are connected in parallel. However, the first electrode assembly and the second electrode assembly may also be connected in series (not shown).

[0083] In this case, all structures are the same as when the first electrode assembly and the second electrode assembly are connected in parallel, but positions of the positive electrode connection tab and the negative electrode connection tab of the connection tabs are changed.

[0084] In addition, a separation wall may be provided between the first electrode assembly and the second electrode assembly to prevent electrolytes contained therein from communicating with each other, thereby preventing a short circuit between the first electrode assembly and the second electrode assembly.

[0085] Although the foregoing embodiments have been described to practice the battery pack according to the present disclosure, it should be understood that the embodiments described herein should be considered only in a descriptive sense and not for purposes of limitation, and that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims.

[0086] Industrial Applicability

[0087] The present invention can be used in the field of secondary batteries in which an electrode assembly is formed to be foldable.

Claims

1. A secondary battery comprising: a first electrode assembly equipped with a first terminal tab and a second terminal tab; a second electrode assembly electrically connected to the first electrode assembly; a plurality of connection tabs disposed between and connected to the first electrode assembly and the second electrode assembly and electrically connecting the first electrode assembly and the second electrode assembly; as well as a case provided with a housing portion opened at one side thereof and having a housing space for housing the first electrode assembly and the second electrode assembly and an electrolyte, and a cover coupled to and covering the open side of the housing portion, Each of the first electrode assembly and the second electrode assembly includes a first electrode plate, a second electrode plate, and a separator interposed between the first electrode plate and the second electrode plate. The connection tabs include a positive electrode connection tab electrically connected to the first electrode plate and a negative electrode connection tab electrically connected to the second electrode plate, respectively, The positive electrode connection terminal tab of the first electrode assembly includes a substrate contact portion connected to the first electrode plate and a connection portion formed integrally with the substrate contact portion and exposed to one side of the first electrode assembly, the negative electrode connection terminal tab of the first electrode assembly includes a substrate contact portion connected to the second electrode plate and a connection portion formed integrally with the substrate contact portion and exposed to one side of the first electrode assembly, the positive electrode connection terminal tab of the second electrode assembly includes a substrate contact portion connected to the first electrode plate and a connection portion formed integrally with the substrate contact portion and exposed to the first electrode assembly, and the negative electrode connection terminal tab of the second electrode assembly includes a substrate contact portion connected to the second electrode plate and a connection portion formed integrally with the substrate contact portion and exposed to the first electrode assembly, When the shell is folded, the shell is folded so that one side and the other side of the outer surface of the cover are brought together.

2. The secondary battery according to claim 1, wherein When the housing is folded, the folded portions of the cover are in close contact with each other. 3 . The secondary battery as claimed in claim 2 , wherein the case further comprises a coupling portion extending along an edge of one side of the opening of the receiving portion so as to extend parallel to the cover to be coupled thereto. 4 . The secondary battery as claimed in claim 3 , wherein when the case is folded, the coupling portion and the cover have a cutout groove formed by cutting an end portion corresponding to the folded portion. 5 . The secondary battery of claim 1 , wherein the first electrode assembly further comprises a first tab electrically connected to the first electrode plate and a second tab electrically connected to the second electrode plate, respectively. 6 . The secondary battery of claim 1 , wherein the first electrode plate is a positive electrode plate having an aluminum substrate, and the second electrode plate is a negative electrode plate having a copper substrate.

7. A secondary battery as described in claim 6, wherein the positive electrode connecting tab of the first electrode assembly includes a substrate contact portion connected to the aluminum substrate and a connecting portion formed integrally with the substrate contact portion and exposed to one side of the first electrode assembly, the negative electrode connecting tab of the first electrode assembly includes a substrate contact portion connected to the copper substrate and a connecting portion formed integrally with the substrate contact portion and exposed to one side of the first electrode assembly, the positive electrode connecting tab of the second electrode assembly includes a substrate contact portion connected to the aluminum substrate and a connecting portion formed integrally with the substrate contact portion and exposed to the first electrode assembly, and the negative electrode connecting tab of the second electrode assembly includes a substrate contact portion connected to the copper substrate and a connecting portion formed integrally with the substrate contact portion and exposed to the first electrode assembly. 8 . The secondary battery of claim 7 , wherein the positive electrode connection tab includes one or two positive electrode connection tabs, and the negative electrode connection tab includes one or two negative electrode connection tabs, respectively. 9 . The secondary battery of claim 8 , wherein the connection tab connected to the first electrode assembly and the connection tab connected to the second electrode assembly overlap each other. 10 . The secondary battery of claim 9 , wherein the connection tab connected to the first electrode assembly and the connection tab connected to the second electrode assembly are disposed to have a step difference from each other. 11 . The secondary battery of claim 9 , wherein an insulating tape is attached to coupling portions of the connection tab connected to the first electrode assembly and the connection tab connected to the second electrode assembly. 12 . The secondary battery as claimed in claim 1 , wherein the first electrode assembly and the second electrode assembly are connected to each other in parallel.

13. The secondary battery of claim 1, wherein the first electrode assembly and the second electrode assembly are connected in series to each other, and the accommodation space is divided into two to accommodate the first electrode assembly and the second electrode assembly, respectively, so that the electrolyte of the first electrode assembly and the electrolyte of the second electrode assembly are not connected to each other.

Images