Patent Publication Number: US-11380966-B2

Title: Secondary battery having a structure for suppressing multi-tab short circuits

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a National Phase Patent Application of International Patent Application Number PCT/KR2018/001616, filed on Feb. 6, 2018, which claims priority of Korean Patent Application No. 10-2017-0023768, filed Feb. 22, 2017. The entire contents of both of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     Various embodiments of the present invention relate a secondary battery having a structure for suppressing multi-tab short circuits. 
     BACKGROUND ART 
     A secondary battery is a power storage system that converts electric energy into chemical energy and stores the converted energy to provide high energy density. Unlike primary batteries that cannot be recharged, a secondary battery is rechargeable and is being widely used in IT devices, such as a smart phone, a cellular phone, a notebook computer, or a tablet PC. In recent years, electric vehicles are drawing attention for protection of environmental contamination, and a trend toward the use of high-capacity secondary batteries for electric vehicles is growing. The secondary battery needs to have high density, high output and stability characteristics. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
     TECHNICAL PROBLEMS TO BE SOLVED 
     Various embodiments of the present invention provide a secondary battery having a structure for suppressing multi-tab short circuits. More particularly, various embodiments of the present invention provide a secondary battery capable of increasing the insulation level of multi-tabs by forming insulating layers on the multi-tabs of an electrode assembly. 
     TECHNICAL SOLUTIONS 
     In accordance with an aspect of the present invention, there is provided a secondary battery including a case, an electrode assembly accommodated inside the case and having multi-tabs, and a cap plate closing the case and having electrode terminals electrically connected to the multi-tabs of the electrode assembly, wherein the surfaces of the multi-tabs are coated with insulating layers. 
     The insulating layers may include an insulating organic material. 
     The insulating layers may include an insulating inorganic material. 
     The insulating layers may include an inorganic filler and an organic binder. 
     The electrode assembly may include a first electrode plate including a first current collector plate and a first electrically active material layer coated on the first current collector plate, a separator positioned at one side of the first electrode plate, and a second electrode plate including a second current collector plate positioned at one side of the separator and a second electrically active material layer coated on the second current collector plate. The multi-tabs may have a structure in which the first current collector plate is upwardly extended to an exterior side of the first electrically active material layer of the first electrode plate. The insulating layers and the separator may be positioned between the multi-tabs and the second electrode plate. The secondary battery may further include a safety function layer (SFL) located on the second electrically active material layer, and the insulating layers, the separator and the SFL may be positioned between the multi-tabs and the second electrode plate. The insulating layers may be brought into contact with the first electrically active material layer. The insulating layers may be spaced apart from the first electrically active material layer. The insulating layers may be brought into contact with the separator. 
     ADVANTAGEOUS EFFECTS 
     As described above, various embodiments of the present invention provide a secondary battery having a structure for suppressing multi-tab short circuits. That is to say, various embodiments of the present invention provide a secondary battery capable of increasing the insulation level of multi-tabs by forming insulating layers on the multi-tabs of an electrode assembly. 
     In an example embodiment, an insulating layer made of an organic material, an inorganic material, and/or an organic-inorganic composite material, is located on one or both surfaces of a positive multi-tab of an electrode assembly, thereby providing a triple insulating structure including the insulating layer between the positive multi-tab and a negative electrode plate, a separator and/or a safety function layer (SFL) (i.e., a ceramic layer coated on a surface of an negative electrode active material layer). Accordingly, even if the positive multi-tab is bent in various types to be connected to an electrode terminal, an electrical short circuit between the positive multi-tab and the negative electrode plate can be suppressed. That is to say, the insulation level of the positive multi-tab can be increased. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIGS. 1A, 1B and 1C  are a perspective view, a cross-sectional view and an exploded perspective view of a secondary battery according to an embodiment of the present invention. 
         FIGS. 2A and 2B  are a plan view and a partial cross-sectional view of first and second electrode assemblies in a secondary battery having a structure for suppressing multi-tab short circuits according to an embodiment of the present invention. 
         FIGS. 3A and 3B  are a plan view and a partial cross-sectional view of first and second electrode assemblies in a secondary battery having a structure for suppressing multi-tab short circuits according to another embodiment of the present invention. 
         FIGS. 4A and 4B  are a plan view and a perspective view of first and second electrode assemblies in a secondary battery having a structure for suppressing multi-tab short circuits according to another embodiment of the present invention. 
         FIGS. 5A and 5B  are enlarged cross-sectional views illustrating states before and after bending multi-tabs according to an embodiment of the present invention. 
         FIGS. 6A and 6B  are enlarged cross-sectional views illustrating states before and after bending multi-tabs according to another embodiment of the present invention. 
         FIGS. 7A and 7B  are enlarged cross-sectional views of multi-tabs according to another embodiment of the present invention. 
         FIGS. 8A to 8C  are schematic views illustrating a manufacturing method of a secondary battery having a structure for suppressing multi-tab short circuits according to an embodiment of the present invention. 
         FIG. 9  is a perspective view illustrating an example of a battery module using a secondary battery having a structure for suppressing multi-tab short circuits according to an embodiment of the present invention. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, a preferred embodiment of the present invention will be described in detail. 
     Various embodiments of the present invention may be embodied in many different forms and should not be construed as being limited to the example embodiments set forth herein. Rather, these example embodiments of the disclosure are provided so that this disclosure will be thorough and complete and will convey inventive concepts of the disclosure to those skilled in the art. 
     In the accompanying drawings, sizes or thicknesses of various components are exaggerated for brevity and clarity. Like numbers refer to like elements throughout. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. In addition, it will be understood that when an element A is referred to as being “connected to” an element B, the element A can be directly connected to the element B or an intervening element C may be present and the element A and the element B are indirectly connected to each other. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprise or include” and/or “comprising or including,” when used in this specification, specify the presence of stated features, numbers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, components, and/or groups thereof. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various members, elements, regions, layers and/or sections, these members, elements, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one member, element, region, layer and/or section from another. Thus, for example, a first member, a first element, a first region, a first layer and/or a first section discussed below could be termed a second member, a second element, a second region, a second layer and/or a second section without departing from the teachings of the present disclosure. 
     Spatially relative terms, such as “below,” “beneath,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “on” or “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. 
     In addition, as used herein, the term “separator” includes a separator generally used in liquid electrolyte batteries using a liquid electrolyte having a low affinity to the separator. Further, as used herein, the term “separator” may include an intrinsic solid polymer electrolyte in which the electrolyte is strongly bound to the separator to then be recognized as being the same as the separator, and/or a gel solid polymer. Therefore, the meaning of the separator should be defined as specifically defined in the specification of the present disclosure. 
     Referring to  FIGS. 1A, 1B and 1C , a perspective view, a cross-sectional view and an exploded perspective view of a secondary battery according to an embodiment of the present invention are illustrated. 
     As shown in  FIGS. 1A, 1B and 1C , the secondary battery  100  according to an embodiment of the present invention may include a case  110 , first and second electrode assemblies  120 A and  120 B, a cap plate  130 , a first electrode terminal  140  and a second electrode terminal  150 . 
     The case  110  may be made of a conductive metal, such as aluminum, an aluminum alloy or nickel plated steel, and may be substantially shaped of a hexahedron having an opening through which the electrode assemblies  120 A and  120 B can be inserted into the case  110 . While the opening is not shown in  FIG. 1B  because the case  110  and the cap plate  130  are assembled with each other, it may be a substantially opened part of a top portion of the case  110 . Meanwhile, since the internal surface of the case  110  is insulated, the case  110  may be insulated from the first and second electrode assemblies  120 A and  120 B. Here, the case  110  may also referred to as a can in some instances. 
     The case  110  may include a first long side portion  111  having a relatively large area, a second long side portion  112  facing the first long side portion  111  and having a relatively large area, a first short side portion  113  connecting first ends of the first and second long side portions  111  and  112  and having a relatively small area, a second short side portion  114  facing the third short side portion  113 , connecting second ends of the first and second long side portions  111  and  112  and having a relatively small area, and a bottom portion  115  connecting the first and second long side portions  111  and  112  and the first and second short side portions  113  and  114 . 
     The first electrode assembly  120 A is assembled inside the case  110 . Particularly, one surface of the first electrode assembly  120 A is coupled to the case  110  in a state in which it is brought into close contact/contact with the first long side portion  111  of the case  110 . The first electrode assembly  120 A may be manufactured by winding or laminating a stacked structure including a first electrode plate  121 , a separator  122 , and a second electrode plate  123 , which are thin plates or layers. Here, the first electrode plate  121  may operate as a positive electrode and the second electrode plate  123  may operate as a negative electrode. Of course, polarities of the first electrode plate  121  and the second electrode plate  123  may be reversed. In addition, if the first electrode assembly  120 A is manufactured in a winding type, a first winding center  125 A (or a first winding leading edge) where winding is started may be located at the center of the first electrode assembly  120 A. 
     The first electrode plate  121  may include a first current collector plate  121   a  made of a metal foil or mesh including aluminum or an aluminum alloy, a first coating portion  121   b  having a first electrically active material, such as a transition metal oxide, on the first current collector plate  121   a , a first non-coating portion (or a first uncoated portion)  121   c  on which the first electrically active material is not coated, and a first electrode first multi-tab  161  outwardly (or upwardly) extended from the first non-coating portion  121   c  and electrically connected to the first electrode terminal  140 . Here, the first electrode first multi-tab  161  may become a passageway of the flow of current between the first electrode plate  121  and the first electrode terminal  140  and may include multiple first electrode first tabs arranged in a stacked type to be referred to as multi-tabs. In addition, the first electrode first multi-tab  161  may be provided such that the first non-coating portion  121   c  is upwardly extended/protruded. Here, the first electrode may be a positive electrode. 
     The second electrode plate  123  may include a second current collector plate  123   a  made of a metal foil or mesh including copper, a copper alloy, nickel or a nickel alloy, a second coating portion  123   b  having a second electrically active material, such as graphite or carbon, on the second current collector plate  123   a , a second non-coating portion (or a second uncoated portion)  123   c  on which the second electrically active material is not coated, and a second electrode first multi-tab  171  outwardly (or upwardly) extended from the second non-coating portion  123   c  and electrically connected to the second electrode terminal  150 . Here, the second electrode first multi-tab  171  may become a passageway of the flow of current between the second electrode plate  123  and the second electrode terminal  150  and may include multiple second electrode first tabs arranged in a stacked type to be referred to as multi-tabs. In addition, the second electrode first multi-tab  171  may be provided such that the second non-coating portion  123   c  is upwardly extended/protruded. Here, the second electrode may be a negative electrode. 
     The separator  122  may be positioned between the first electrode plate  121  and the second electrode plate  123  to prevent an electrical short circuit from occurring between the first electrode plate  121  and the second electrode plate  123  and to allow movement of lithium ions. The separator  122  may include polyethylene, polypropylene or a composite film of polyethylene and polypropylene. However, the material of the separator  122  is not limited to the specific materials listed herein. In addition, if an inorganic solid electrolyte is used, the separator  122  may not be provided. 
     The second electrode assembly  120 B may have substantially the same structure, type and/or material as those of the first electrode assembly  120 A. Therefore, detailed descriptions of the second electrode assembly  120 B will be omitted. However, one surface of the second electrode assembly  120 B is coupled to the case  110  in a state in which it is brought into close contact/contact with the second long side portion  112  of the case  110 . In addition, if the second electrode assembly  120 B is manufactured in a winding type, a second winding center  125 B (or a second winding leading edge) where winding is started may be located at the center of the second electrode assembly  120 B. 
     In addition, the first and second electrode assemblies  120 A and  120 B include a boundary area where the first and second electrode assemblies  120 A and  120 B face each other inside the case  110  or a contact area  190  where the first and second electrode assemblies  120 A and  120 B are brought into close contact/contact with each other. That is to say, the first and second electrode assemblies  120 A and  120 B may be assembled inside the case  110  in a state in which they are brought into close contact/contact with each other. 
     Meanwhile, the second electrode assembly  120 B may include a first electrode second multi-tab  162  outwardly (or upwardly) extended from the first electrode plate  121  and electrically connected to the first electrode terminal  140 . Here, the first electrode second multi-tab  162  may become a passageway of the flow of current between the first electrode plate  121  and the first electrode terminal  140  and may include multiple first electrode second tabs arranged in a stacked type to be referred to as multi-tabs. In addition, the first electrode second multi-tab  162  may be provided such that the first non-coating portion  121   c  is upwardly extended/protruded. 
     In addition, the second electrode assembly  120 B may include a second electrode second multi-tab  172  outwardly (or upwardly) extended from the second electrode plate  123  and electrically connected to the second electrode terminal  150 . Here, the second electrode second multi-tab  172  may become a passageway of the flow of current between the second electrode plate  123  and the second electrode terminal  150  and may include multiple second electrode second tabs arranged in a stacked type to be referred to as multi-tabs. In addition, the second electrode second multi-tab  172  may be provided such that the second non-coating portion  123   c  is upwardly extended/protruded. 
     Meanwhile, an axis of each of the first and second winding centers  125 A and  125 B of the first and second electrode assemblies  120 A and  120 B, that is, a winding axis, is substantially parallel or horizontal to a terminal axis of each of the first and second electrode terminals  140  and  150 . Here, the winding axis and the terminal axis may mean an up-and-down axis in  FIGS. 1B and 1C , and the expression “the winding axis and the terminal axis being substantially parallel or horizontal to each other” may mean that the winding axis and the terminal axis may not meet each other even if the winding axis and the terminal axis are extended or may meet each other when the winding axis and the terminal axis are extraordinarily extended. 
     In addition, as described above, the first and second multi-tabs  161  and  162  extended and bent a predetermined length are positioned between the first and second electrode assemblies  120 A and  120 B and the first electrode terminal  140 , and the first and second multi-tabs  171  and  172  extended and bent a predetermined length are positioned between the first and second electrode assemblies  120 A and  120 B and the second electrode terminal  150 . That is to say, the first and second multi-tabs  161  and  162  located at one side may be extended and bent from top ends of the first and second electrode assemblies  120 A and  120 B toward the first electrode terminal  140  so as to be substantially symmetrical with each other to then be connected or welded to the first electrode terminal  140 . In addition, the first and second multi-tabs  171  and  172  located at the other side may also be extended and bent from the top ends of the first and second electrode assemblies  120 A and  120 B toward the second electrode terminal  150  so as to be substantially symmetrical with each other to then be connected or welded to the second electrode terminal  150 . 
     Substantially, each of the first and second multi-tabs  161  and  162  located at one side may be the first non-coating portion  121   c  itself, which is a region of the first electrode plate  121 , without a first active material coated thereon, or may be a separate member connected to the first non-coating portion  121   c . Here, the separate member may be made of one selected from the group consisting of aluminum, an aluminum alloy, nickel, a nickel alloy, copper, a copper alloy, and equivalents thereof. 
     In addition, each of the first and second multi-tabs  171  and  172  located at the other side may be the second non-coating portion  123   c  itself, which is a region of the second electrode plate  123 , without a second active material coated thereon, or may be a separate member connected to the second non-coating portion  123   c . Here, the separate member may be made of one selected from the group consisting of nickel, a nickel alloy, copper, a copper alloy, aluminum, an aluminum alloy, and equivalents thereof. 
     As described above, since the first and second winding axes of the first and second electrode assemblies  120 A and  120 B and the terminal axes of the first and second electrode terminals  140  and  150  are substantially parallel or horizontal to each other, as described above, an electrolyte injection direction and the winding axes are also substantially parallel or horizontal to each other. Therefore, the first and second electrode assemblies  120 A and  120 B exhibit high electrolyte impregnation capability when an electrolyte is injected and internal gases are rapidly transferred to a safety vent  136  during over-charge, enabling the safety vent  136  to quickly operate. 
     In addition, the first and second multi-tabs  161 / 171  and  162 / 172  (or uncoated portions or separate members) of the first and second electrode assemblies  120 A and  120 B are extended and bent to be are directly electrically connected to the first and second electrode terminals  140  and  150 , which shortens electrical paths, thereby reducing internal resistance of the secondary battery  100  while reducing the number of components of the secondary battery  100 . 
     In particular, since the first and second multi-tabs  161 / 171  and  162 / 172  (or uncoated portions or separate members) of the first and second electrode assemblies  120 A and  120 B are directly electrically connected to first and second electrode terminals  140  and  150  while being symmetrical with each other, unnecessary electrical short circuits between the first and second multi-tabs  161 / 171  and  162 / 172  and regions having polarities opposite to the first and second multi-tabs  161 / 171  or  162 / 172  (e.g., the case, cap plate and/or predetermined portions of the first and second electrode assemblies  120 A and  120 B can be prevented. In other words, insulation levels of the first and second multi-tabs  161 / 171  and  162 / 172  can be improved by the symmetrical structure of the first and second multi-tabs  161 / 171  and  162 / 172 . 
     The first and second electrode assemblies  120 A and  120 B may be accommodated in the case  110  together with an electrolyte. The electrolyte may include an organic solvent, such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), or dimethyl carbonate (DMC), and a lithium salt such as LiPF 6  or LiBF 4 . In addition, the electrolyte may be in a liquid, sold or gel phase. 
     The cap plate  130  may be substantially shaped of a rectangle having lengths and widths and may be coupled to the case  110 . That is to say, the cap plate  130  may seal an opening of the case  110  and may be made of the same material as the case  110 . For example, the cap plate  130  may be coupled to the case  110  by laser and/or ultrasonic welding. Here, the cap plate  130  may also be referred to as a cap assembly in some instances. 
     The cap plate  130  may include a plug  134  closing an electrolyte injection hole, and a safety vent  136  clogging a vent hole. In addition, the safety vent  136  may include a notch configured to be easily opened at a preset pressure. 
     The first electrode terminal  140  may include a first electrode terminal plate  141  positioned on a top surface of the cap plate  130 , a first upper insulation plate  142  positioned between the first electrode terminal plate  141  and the cap plate  130 , a first lower insulation plate  143  positioned on a bottom surface of the cap plate  130 , a first current collector plate  144  positioned on a bottom surface of the first lower insulation plate  143 , and a first electrode terminal pillar  145  electrically connecting the first electrode terminal plate  141  and the first current collector plate  144 . In addition, the secondary battery  100  according to an embodiment of the present invention may further include a first seal insulation gasket  146  insulating the cap plate  130  and the first electrode terminal pillar  145  from each other. 
     Here, the first and second multi-tabs  161  and  162  of the first and second electrode assemblies  120 A and  120 B may be electrically connected to the first current collector plate  144  of the first electrode terminal  140  so as to be symmetrical with each other. 
     The second electrode terminal  150  may include a second electrode terminal plate  151  positioned on the top surface of the cap plate  130 , a second upper insulation plate  152  positioned between the second electrode terminal plate  151  and the cap plate  130 , a second lower insulation plate  153  positioned on the bottom surface of the cap plate  130 , a second current collector plate  154  positioned on a bottom surface of the second lower insulation plate  153 , and a second electrode terminal pillar  145  electrically connecting the second electrode terminal plate  151  and the second current collector plate  154 . In addition, the secondary battery  100  according to an embodiment of the present invention may further include a second seal insulation gasket  156  insulating the cap plate  130  and the second electrode terminal pillar  155  from each other. 
     Here, the first and second multi-tabs  171  and  172  of the first and second electrode assemblies  120 A and  120 B may be electrically connected to the second current collector plate  154  of the second electrode terminal  150  so as to be symmetrical with each other. 
     Meanwhile, in an embodiment of the present invention, an insulation plate  180  is further positioned between each of the first and second electrode assemblies  120 A and  120 B, the first and second multi-tabs  161 / 171  and  162 / 172  and the first and second electrode terminals  140  and  150 , thereby preventing the first and second multi-tabs  161 / 171  or  162 / 172  and regions having polarities opposite to the first and second multi-tabs  161 / 171  or  162 / 172  (e.g., the case, the cap plate and/or the predetermined regions of the first and second electrode assemblies) from being electrically short-circuited to each other. The insulation plate  180  may be made of, for example, but not limited to, a super engineering plastic, such as polyphenylene sulfide (PPS), having excellent dimension stability and maintaining a high strength and stiffness up to approximately 220° C. 
     As described above, in the secondary battery  100  according to the embodiment of the present invention, the first and second multi-tabs  161 / 171  and  162 / 172  of the first and second electrode assemblies  120 A and  120 B are configured such that they are extended and bent to be symmetrical with each other with respect to the boundary area (or contact area)  190  between the first and second electrode terminals  140  and  150  or the first and second electrode assemblies  120 A and  120 B), thereby preventing the first and second multi-tabs  161 / 171  or  162 / 172  and the regions having polarities opposite to the first and second multi-tabs  161 / 171  or  162 / 172  (e.g., the case  110 , the cap plate  130  and/or the predetermined regions of the first and second electrode assemblies  120 A and  120 B) from being electrically short-circuited to each other. 
     That is to say, if the first and second multi-tabs  161 / 171  and  162 / 172  are configured to be symmetrical with each other with respect to the boundary area  190  between the first and second electrode terminals  140  and  150  or the first and second electrode assemblies  120 A and  120 B, a probability of electrical short circuits occurring between the first and second multi-tabs  161 / 171  and  162 / 172  and the case  110 , the cap plate  130  and/or the predetermined regions of the first and second electrode assemblies  120 A and  120 B having polarities opposite to the first and second multi-tabs  161 / 171  or  162 / 172 , may be increased. However, like in the embodiment of the present invention, if the first and second multi-tabs  161  and  162  are configured to be symmetrical with each other, the probability of occurrence of such electrical short circuits can be reduced. 
     For example, a probability of electrical short circuits occurring between the positive electrode first and second multi-tabs  161  and  162  configured to be symmetrical with each other and the negative electrode non-coating portions  123   c  of the first and second electrode assemblies  120 A and  120 B, is smaller than a probability of electrical short circuits occurring between positive electrode first and second multi-tabs configured to be asymmetrical with each other and negative electrode non-coating portions of first and second electrode assemblies, but aspects of the present invention are not limited thereto. In addition, for example, a probability of electrical short circuits occurring between the negative electrode first and second multi-tabs  171  and  172  configured to be symmetrical with each other and the positive electrode non-coating portions  121   c  of the first and second electrode assemblies  120 A and  120 B, is smaller than a probability of electrical short circuits occurring between negative electrode first and second multi-tabs configured to be asymmetrical with each other and positive electrode non-coating portions of first and second electrode assemblies, but aspects of the present invention are not limited thereto. 
     In other words, if the first and second multi-tabs  161 / 171  and  162 / 172  of the first and second electrode assemblies  120 A and  120 B are configured to be symmetrical with each other, the number or area of management regions for preventing electrical short circuits between the first and second multi-tabs  161 / 171  or  162 / 172  and the regions having opposite polarities, that is, the case  110 , the cap plate  130  and/or the predetermined regions of the first and second electrode assemblies  120 A and  120 B, may be reduced. Accordingly, the electrical short circuits between the first and second multi-tabs  161 / 171  and  162 / 172  and the regions having the opposite polarities can be easily prevented. However, if the first and second multi-tabs  161 / 171  and  162 / 172  of the first and second electrode assemblies  120 A and  120 B are configured to be asymmetrical with each other, the number or area of management regions for preventing electrical short circuits between the first and second multi-tabs  161 / 171  or  162 / 172  and the regions having opposite polarities, may be increased. Accordingly, it is difficult to prevent the electrical short circuits between the first and second multi-tabs  161 / 171  and  162 / 172  and the regions having the opposite polarities. 
     Referring to  FIGS. 2A and 2B , a plan view and a partial cross-sectional view of first and second electrode assemblies in a secondary battery having a structure for suppressing multi-tab short circuits according to an embodiment of the present invention are illustrated. 
     As shown in  FIGS. 2A and 2B , the first electrode assembly  120 A may include a first winding center  125 A (or a first winding leading edge) where winding is started, and the second electrode assembly  120 B may also include a second winding center  125 B (or a second winding leading edge) where winding is started. In addition, the first and second electrode assemblies  120 A and  120 B may have a boundary area (or contact area)  190 ) therebetween. 
     In the following description, outer regions of the first and second electrode assemblies  120 A and  120 B may mean regions spaced apart from the boundary area  190  between the first and second electrode assemblies  120 A and  120 B and closer to the first and second long side portions  111  or  112  of the case  110 , and inner regions of the first and second electrode assemblies  120 A and  120 B may mean regions spaced apart from the first and second long side portions  111  or  112  of the case  110  and closer to the boundary area  190  between the first and second electrode assemblies  120 A and  120 B. In addition, in the following description, the outer regions of the first and second electrode assemblies  120 A and  120 B may mean regions from the first and second winding centers  125 A or  1256  to the first and second long side portions  111  or  112  of the case  110 , and the inner regions of the first and second electrode assemblies  120 A and  120 B may mean regions from the first and second winding centers  125 A or  125 B to the boundary area  190  between the first and second electrode assemblies  120 A and  120 B. It should be understood that definitions of the outer and inner regions of the first and second electrode assemblies  120 A and  120 B can be commonly applied to all embodiments of the present invention. 
     As shown in  FIG. 2A , the first and second electrode assemblies  120 A and  120 B may include the first and second multi-tabs  161 / 162  or  171 / 172  located at their outer regions so as to be symmetrical with each other with respect to the boundary area  190 . The first multi-tabs  161  and  171  may be located only at, for example, but not limited to, the outer region of the first electrode assembly  120 A. That is to say, the first multi-tabs  161  and  171  may not be located at the inner regions of the first electrode assembly  120 A. In addition, the second multi-tabs  162  and  172  may also be located only at the outer regions of the second electrode assembly  120 B. That is to say, the second multi-tabs  162  and  172  may not be located at the inner regions of the second electrode assembly  120 B. More specifically, as shown in  FIG. 2A , the first multi-tabs  161  and  171  may be located only at roughly upper regions of the first winding center  125 A in the first electrode assembly  120 A (i.e., regions adjacent to the first long side portion  111  of the case  110 ), and the second multi-tabs  162  and  172  may be located only at roughly lower regions of the second winding center  125 B in the second electrode assembly  120 B (i.e., regions adjacent to the second long side portion  112  of the case  110 ). Therefore, the maximum distance between the first and second multi-tabs  161 / 162  or  171 / 172  may be equal to or slightly smaller than the maximum overall width (or thickness) of the first and second electrode assemblies  120 A and  120 B. 
     In addition, as shown in  FIG. 2B , the first and second electrode assemblies  120 A and  120 B may include the first and second multi-tabs  161  and  162  extended and bent from the outer regions so as to be symmetrical with each other with respect to the boundary area  190  or the electrode terminal  140 . The first and second multi-tabs  161  and  162  may be extended and bent from, for example, but not limited to, the outer regions of the first and second electrode assemblies  120 A and  120 B to the electrode terminal  140  so as to be symmetrical with each other with respect to the boundary area  190 . In other words, the first and second multi-tabs  161  and  162  may be extended and bent to the electrode terminal  140  from regions closer to the case  110  (i.e., the first long side portion or the second long side portion) than to the boundary area  190  between the first and second electrode assemblies  120 A and  120 B, respectively. 
     Still in other words, the first and second multi-tabs  161  and  162  may include first regions  161   a  and  162   a  extended from the outer regions of the first and second electrode assemblies  120 A and  120 B, second regions  161   b  and  162   b  extended from the first regions  161   a  and  162   a  to be adjacent to the case  110 , and third regions  161   c  and  162   c  bent from the second regions  161   b  and  162   b  to be electrically connected to the electrode terminal  140 , respectively. 
     Here, as the first regions  161   a  and  162   a  get closer from the case  110  (i.e., the first long side portion or the second long side portion) to the boundary area  190  between the first and second electrode assemblies  120 A and  120 B, bending angles of the first regions  161   a  and  162   a  are more increased. In addition, the second regions  161   b  and  162   b  may be substantially parallel with a longitudinal direction of the case  110  (i.e., the first long side portion or the second long side portion). In addition, the third regions  161   c  and  162   c  may be connected to the electrode terminal  140  while being bent roughly at right angle from the second regions  161   b  and  162   b.    
     In addition, since the insulation plate  180  is further located between the first and second electrode assemblies  120 A and  120 B and the first and second multi-tabs  161  and  162 , and the electrode terminal  140 , electrical short circuits may not occur between the first and second multi-tabs  161  and  162 , and the case, the cap plate and/or the predetermined regions of the first and second electrode assemblies, which have polarities opposite to the first and second multi-tabs  161  and  162 . In particular, the insulation plate  180  is placed roughly on the separator  122  of each of the first and second electrode assemblies  120 A and  120 B. 
     As described above, according to the embodiment of the present invention, the first and second multi-tabs  161  and  162  are extended and bent from the outer regions of the first and second electrode assemblies  120 A and  120 B to the electrode terminal  140  so as to be symmetrical with each other with respect to the electrode terminal  140  or the boundary area  190  between the first and second electrode assemblies  120 A and  120 B, thereby suppressing electrical short circuits between the first and second multi-tabs  161  and  162  and the regions having polarities opposite thereto (e.g., the case, the cap plate and/or the predetermined regions of the first and second electrode assemblies). 
     Referring to  FIGS. 3A and 3B , a plan view and a partial cross-sectional view of first and second electrode assemblies in a secondary battery having a structure for suppressing multi-tab short circuits according to another embodiment of the present invention are illustrated. 
     As shown in  FIG. 3A , the first and second electrode assemblies  120 A and  120 B may include first and second multi-tabs  261 / 262  or  271 / 272  located at their inner regions so as to be symmetrical with each other with respect to the boundary area  190  between the first and second electrode assemblies  120 A and  120 B. The first multi-tabs  261  and  271  may be located only at, for example, but not limited to, the inner regions of the first electrode assembly  120 A. That is to say, the first multi-tabs  261  and  271  may not be located at the outer regions of the first electrode assembly  120 A. In addition, the second multi-tabs  262  and  272  may also be located only at the inner regions of the second electrode assembly  120 B. That is to say, the second multi-tabs  262  and  272  may not be located at the outer regions of the second electrode assembly  120 B. More specifically, as shown in  FIG. 3A , the first multi-tabs  261  and  271  may be located only at roughly lower regions of the first winding center  125 A in the first electrode assembly  120 A (i.e., regions adjacent to the boundary area  190 ), and the second multi-tabs  262  and  272  may be located only at roughly upper regions of the second winding center  125 B in the second electrode assembly  120 B (i.e., regions adjacent to the boundary area  190 ). Therefore, the maximum distance between the first and second multi-tabs  261 / 262  or  271 / 272  may be equal to or slightly greater than the minimum distance between the first and second electrode assemblies  120 A and  120 B. 
     In addition, as shown in  FIG. 3B , the first and second electrode assemblies  120 A and  120 B may include the first and second multi-tabs  261  and  262  extended and bent from the inner regions so as to be symmetrical with each other with respect to the boundary area  190  between first and second electrode assemblies  120 A and  120 B or the electrode terminal  140 . The first and second multi-tabs  261  and  262  may be extended and bent, for example, but not limited to, from the inner regions of the first and second electrode assemblies  120 A and  120 B to the electrode terminal  140  so as to be symmetrical with each other, respectively. In other words, the first and second multi-tabs  261  and  262  may be extended and bent to the electrode terminal  140  from regions closer to the boundary area  190  between the first and second electrode assemblies  120 A and  120 B than to the first long side portion  111  or the second long side portion  112  of the case  110 . 
     Still in other words, the first and second multi-tabs  261  and  262  may include first regions  261   a  and  262   a  extended from the inner regions of the first and second electrode assemblies  120 A and  120 B, second regions  261   b  and  262   b  extended from the first regions  261   a  and  262   a  to be adjacent to the case  110 , and third regions  261   c  and  262   c  bent from the second regions  261   b  and  262   b  to be electrically connected to the electrode terminal  140 , respectively. 
     Here, as the first regions  261   a  and  262   a  get closer from the case  110  to the boundary area  190  between the first and second electrode assemblies  120 A and  120 B, bending angles of the first regions  261   a  and  262   a  are more increased. In addition, the second regions  261   b  and  262   b  may be substantially parallel with a longitudinal direction of the case  110 . In addition, the third regions  261   c  and  262   c  may be connected to the electrode terminal  140  while being bent roughly at right angle from the second regions  261   b  and  262   b.    
     In addition, since the insulation plate  180  is further located between the first and second electrode assemblies  120 A and  120 B and the first and second multi-tabs  261  and  262 , and the electrode terminal  140 , electrical short circuits may not occur between the first and second multi-tabs  261  and  262 , and the case, the cap plate and/or the predetermined regions of the first and second electrode assemblies, which have polarities opposite to the first and second multi-tabs  261  and  262 . In particular, the insulation plate  180  is placed roughly on the first regions  261   a  and  262   a  of the first and second multi-tabs  261  and  262 . 
     As described above, according to the embodiment of the present invention, the first and second multi-tabs  261  and  262  are extended and bent from the inner regions of the first and second electrode assemblies  120 A and  120 B to the electrode terminal  140  so as to be symmetrical with each other with respect to the electrode terminal  140  or the boundary area  190  between the first and second electrode assemblies  120 A and  120 B, thereby suppressing electrical short circuits between the first and second multi-tabs  261  and  262  and the regions having polarities opposite thereto (e.g., the case, the cap plate and/or the predetermined regions of the first and second electrode assemblies). 
     Referring to  FIGS. 4A and 4B , a plan view and a perspective view of first and second electrode assemblies in a secondary battery having a structure for suppressing multi-tab short circuits according to another embodiment of the present invention are illustrated. 
     As shown in  FIGS. 4A and 4B , the first and second electrode assemblies  120 A and  120 B may include first and second multi-tabs (or outer multi-tabs)  361  and  362  located at their outer regions and first and second multi-tabs (or inner multi-tabs)  371  and  372  located at their inner regions. 
     For example, in  FIGS. 4A and 4B , the first and second multi-tabs  361  and  362  located roughly in the left sides of the first and second electrode assemblies  120 A and  120 B may be symmetrical with outer regions (i.e., regions each adjacent to a first long side portion or a second long side portion) of the first and second electrode assemblies  120 A and  120 B, and the first and second multi-tabs  371  and  372  located roughly in the right sides of the first and second electrode assemblies  120 A and  120 B may be symmetrical with inner regions (i.e., regions each adjacent to the boundary area) of the first and second electrode assemblies  120 A and  120 B. Here, the left-side first and second multi-tabs  361  and  362  may be positive electrode tabs, and the right-side first and second multi-tabs  371  and  372  may be negative electrode tabs. 
     In more detail, in the first electrode assembly  120 A, the left-side first multi-tab  361  (positive electrode) may be located at the outer region of the first electrode assembly  120 A, and the right-side first multi-tab  371  (negative electrode) may be located at the inner region of the first electrode assembly  120 A. In the second electrode assembly  120 B, the left-side first multi-tab  362  (positive electrode) may be located at the outer region of the second electrode assembly  120 B, and the right-side first multi-tab  372  (negative electrode) may be located at the inner region of the second electrode assembly  120 B. 
     Still in other words, the first and second multi-tabs  361  and  362  of the first and second electrode assemblies  120 A and  120 B may be symmetrical with each other, and the left-side first multi-tab  361  (positive electrode) and the right-side first multi-tab  371  (negative electrode) of the first electrode assembly  120 A are extended and bent to be symmetrical with each other to then be coupled to the first and second electrode terminals  140  and  150 , respectively. In addition, the first and second multi-tabs  371  and  372  of the first and second electrode assemblies  120 A and  120 B may be symmetrical with each other, and the left-side second multi-tab  362  (positive electrode) and the right-side second multi-tab  372  (negative electrode) of the second electrode assembly  120 B are extended and bent to be symmetrical with each other to then be coupled to the first and second electrode terminals  140  and  150 , respectively. 
     Therefore, the first electrode assembly  120 A is coupled to the first and second electrode terminals  140  and  150 , respectively, in a state in which the positive electrode first multi-tab  361  and the negative electrode first multi-tab  371  are symmetrical with each other, and the second electrode assembly  120 B is coupled to the first and second electrode terminals  140  and  150 , respectively, in a state in which the positive electrode second multi-tab  362  and the negative electrode second multi-tab  372  are symmetrical with each other, thereby improving coupling strength, coupling stiffness and coupling reliability between the first and second electrode assemblies  120 A and  120 B and the first and second electrode terminals  140  and  150 . 
     Referring to  FIGS. 5A and 5B , enlarged cross-sectional views illustrating states before and after bending multi-tabs according to an embodiment of the present invention are illustrated. Here,  FIG. 5A  shows a state before bending the multi-tabs  161  of the electrode assembly  120 A. As shown in  FIG. 5A , the multi-tabs  161  are directly extended in forms of straight lines. In addition,  FIG. 5B  shows a state after bending the multi-tabs  161  of the electrode assembly  120 A by connecting the multi-tabs  161  of the electrode assembly  120 A to the electrode terminal  140 . As shown in  FIG. 5B , the multi-tabs  161  are bent in a roughly L-shaped configuration. 
     As shown in  FIGS. 5A and 5B , the electrode assembly  120 A may include the first electrode plate  121 , the separator  122  and the second electrode plate  123 , as described above. 
     Here, the first electrode plate  121  may have, for example, but not limited to, a positive polarity, and may include a first current collector plate  121   a  having a substantially planar first surface  121   d  and a substantially planar second surface  121   e  opposite to the first surface  121   d . In addition, the first electrode plate  121  may have a first electrically active material layer  121   b  coated on the first surface  121   d  and/or the second surface  121   e  of the first current collector plate  121   a.    
     The multi-tabs  161  may have, for example, but not limited to, a structure in which the first current collector plate  121   a  or the non-coating portion  121   c  (see  FIG. 1C ) is upwardly extended to an exterior side of the first electrically active material layer  121   b  of the first electrode plate  121 . Therefore, the multi-tab  161  may also have a substantially planar first surface  161   d  and a substantially planar second surface  161   e  opposite to the first surface  161   d . In addition, the first surface  121   d  of the first current collector plate  121   a  and the first surface  161   d  of the multi-tab  161  may be substantially coplanar, and the second surface  121   e  of the first current collector plate  121   a  and the second surface  161   e  of the multi-tab  161  may also be substantially coplanar. In addition, the first current collector plate  121   a  and the multi-tabs  161  may have substantially the same thickness. Of course, in addition to the configuration stated above, the multi-tabs  161  may also be provided by attaching a separate member to the first current collector plate  121   a  or the non-coating portion  121   c  outwardly extended from the first electrically active material layer  121   b.    
     The separator  122  is positioned between the first electrode plate  121  and the second electrode plate  123 . A length (or height) of the separator  122  may be greater than a length (or height) of the first electrode plate  121  and/or the second electrode plate  123 . That is to say, a top end of the separator  122  may be positioned higher than top ends of the first electrode plate  121  and/or the second electrode plate  123 . 
     The second electrode plate  123  may have, for example, but not limited to, a negative polarity. The second electrode plate  123  is located at one side of the separator  122  and may include a second current collector plate  123   a  having a substantially planar first surface  123   d  and a substantially planar second surface  123   e  opposite to the first surface  123   d , and a second electrically active material layer  123   b  coated on the first surface  123   d  and/or the second surface  123   e  of the second current collector plate  123   a . In addition, a safety function layer (SFL)  123   f  allowing lithium ions to pass while blocking migration electrons may be further located on a surface of the second electrically active material layer  123   b . The SFL  123   f  may be made of, for example, but not limited to, an inorganic material, such as ceramic, and may suppress decomposition of electrolyte by blocking the electron migration. 
     Here, the length (or height) of the second electrode plate  123  may be greater than that of the first electrode plate  121 . Thus, excessive lithium ions or metallic ions may not exist inside the electrode assembly  120 A (particularly, on the surface of the second electrically active material layer). In addition, the length (or height) of the separator  122  is largest, and the length (or height) of the first electrode plate  121 , exclusive of the multi-tab  161 , is smallest. 
     In addition, since the separator  122  is positioned between the multi-tab  161  and the second electrode plate  123 , the multi-tab  161  can be prevented from being directly electrically short-circuited to the second electrode plate  123  (e.g., the second current collector plate  123   a  or the second electrically active material layer  123   b ) even if the multi-tab  161  is bent to be connected to the electrode terminal  140 . 
     In addition, in the embodiment of the present invention, in order to more efficiently suppress the multi-tab short circuit, insulating layers  280  may be coated on surfaces of the multi-tabs  161 . That is to say, the insulating layers  280  may be coated on the first surface  161   d  and/or the second surface  161   e  of the multi-tab  161 . The insulating layers  280  may be coated on the first surface  161   d  and/or the second surface  161   e  while being in contact with the first electrically active material layer  121   b . Moreover, a topmost height of each of the insulating layers  280  may be equal to, for example, a topmost height of each of the separators  122 . If the topmost height of the insulating layer  280  is smaller than that of the separator  122 , the multi-tabs  161  may be at risk of being brought into direct contact with the second electrode plate  123  (e.g., the second current collector plate  123   a , the second electrically active material layer  123   b , etc.) when they are bent. In addition, if the topmost height of the insulating layer  280  is larger than that of the separator  122 , the insulation level of the multi-tab  161  is increased, but the insulating efficiency between the multi-tabs  161  and the second electrode plate  123  may not be improved any more. 
     A thickness of the insulating layer  280  may be smaller than a thickness of the first electrically active material layer  121   b . The thickness of the first electrically active material layer  121   b  may be in the range from, for example, but not limited to, about 100 μm to about 600 μm, and the thickness of the insulating layer  280  may be in the range from about 0.1 μm to about 100 μm, preferably from about 1 μm to about 50 μm, more preferably from about 3 μm to about 8 μm. If the thickness of the insulating layer  280  is larger than that of the first electrically active material layer  121   b , the overall thickness of the electrode assembly  120 A may be increased as much as the thickness of the insulating layer  280 , and the multi-tabs  161  may not be properly bent. Moreover, when the multi-tabs  161  are bent, the insulating layers  280  may be separated away from the multi-tabs  161 . 
     As described above, a double insulating structure including the insulating layer  280  and the separator  122  may be positioned between the multi-tabs  161  and the second electrode plate  123 , thereby preventing electrical short circuits between the multi-tabs  161  and the second electrode plate  123 , that is, increasing the insulation level of the multi-tabs  161 . 
     Moreover, a triple insulating structure including the insulating layer  280 , the separator  122  and the SFL  123   f  may be positioned between the multi-tabs  161  and the second electrode plate  123 , thereby more efficiently preventing electrical short circuits between the multi-tabs  161  and the second electrode plate  123 . That is to say, the insulation level of the multi-tabs  161  may be further increased. 
     The insulating layer  280  may be made of, for example, but not limited to, an organic material, an inorganic material, or an organic-inorganic composite (or hybrid) material, using one or a combination of processes selected from the group consisting of inkjet printing, coating, dip coating, doctor blade, dry dipping, hydro thermal reaction, sol-gel, spraying, aerosol deposition, chemical vapor deposition, physical vapor deposition, roll to roll, casting, an ion beam deposition, and equivalents thereof. 
     In addition, the organic material (or binder) may include, for example, but not limited to, one or a mixture of materials selected from the group consisting of polyimide (PI), polyamideimide (PA), polyvinylidene fluoride (PVdF), polyurethane (PU), polyurea, polycarbonate (PC), polyethylene terephthalate (PET) polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT), polyvinyl alcohol (PVA), polyvinyl butyral (PVB) and equivalents thereof. 
     In addition, the inorganic may include, for example, but not limited to, one or a mixture of two materials selected from the group consisting of alpha alumina (α-Al2O3), alumina (Al2O3), aluminum hydroxide (Al(OH)3, bohemite), lead zirconate titanate (Pb(Zr,Ti)O3(PZT)), titanium dioxide (TiO 2 ), zirconia (ZrO 2 ), yttria (Y 2 O 3 ), yttria stabilized zirconia (YSZ), dysprocia (Dy 2 O 3 ), gadolinia (Gd 2 O 3 ), ceria (CeO 2 ), gadolinia doped ceria (GDC), magnesia (MgO), barium titanate (BaTiO 3 ), nickel manganite (NiMn 2 O 4 ), potassium sodium niobate (KNaNbO 3 ), bismuth potassium titanate (BiKTiO 3 ), bismuth sodium titanate (BiNaTiO 3 ), bismuth ferrite (BiFeO 3 ), bismuth zinc niobate (Bi 1-5 Zn 1 Nb 1.5 O 7 ), tungsten oxide (WO), tin oxide (SnO2), lanthanum-strontium-manganese oxide (LSMO), lanthanum-strontium-iron-cobalt oxide (LSFC), aluminum nitride (AlN), silicon nitride (SiN), silicon oxide (SiO2), zinc oxide (ZnO), hafnia (HfO2), titanium nitride (TiN), silicon carbide (SiC), titanium carbide (TiC), tungsten carbide (WC), magnesium boride (MgB), titanium boride (TiB), calcium oxide (CaO), cobalt ferrite (CoFe2O4), nickel ferrite (NiFe2O4), barium ferrite (BaFe2O4), nickel zinc ferrite (NiZnFe2O4), zinc ferrite (ZnFe2O4), manganese cobalt spinel oxide MnxCo3-xO4 (where x is a positive real number 3 or less), a mixture of metal oxide and metal nitride, a mixture of metal oxide and metal carbide, a mixture of ceramic and polymer, a mixture of ceramic and metal, and equivalents thereof. 
     In addition, the average particle diameter of the inorganic material may be in the range from, for example, but not limited to, about 0.1 μm to about 100 μm, preferably from about 0.3 μm to about 10 μm, more preferably from about 0.5 μm to about 5 μm. 
     Meanwhile, in order to allow the multi-tabs  161  to be electrically connected to the electrode terminal  140 , the multi-tabs  161  are bent in a roughly L-shaped configuration. Or after the multi-tabs  161  are connected to the electrode terminal  140 , the multi-tabs  161  are bent in a roughly L-shaped configuration. Here, since the multi-tabs  161  are bent while being in close contact with each other, not only the multi-tabs  161  but also the separator  122  and/or the second electrode plate  123  are bent at a predetermined angle. In particular, the separators  122  are bent with the multi-tabs  161 , as shown in  FIG. 5B . Here, since the insulating layers  280  are coated on the surfaces of the multi-tabs  161 , as described above, the insulating layers  280  are also bent. 
     Therefore, the multi-tabs  161  and the insulating layers  280  are brought into contact with/close contact with the separator  122  while being bent. Although  FIG. 5B  shows that the multi-tabs  161 , the separator  122  and the second electrode plate  123  are spaced apart from one another, they may be substantially brought into contact/close contact with one another. Here, the electrical short circuits can be prevented from occurring between the multi-tabs  161  and the and the second electrode plate  123  (i.e., the second current collector plate  123   a  and/or the second electrically active material layer  123   b ) by the double insulating structure including the insulating layer  280  and the separator  122 , or the triple insulating structure including the insulating layer  280 , the separator  122  and the SFL  123   f , positioned between the multi-tab  161  and the second electrode plate  123 . 
     In order to more improve the insulation efficiency, the insulating layer  280  that is the same as described may be located on the surface of the second current collector plate  123   a  exposed through the second electrically active material layer  123   b . Therefore, a triple insulating structure including the insulating layer  280 , the separator  122  and the insulating layer  280  may be provided between the multi-tabs  161  and the second current collector plate  123   a , thereby improving the insulating efficiency between the multi-tabs  161  and the second current collector plate  123   a.    
     Meanwhile, the mutual relationships, materials, types and configurations of the insulating layers  280 , the first electrode plate  121 , the separators  122  and the second electrode plate  123  located on the multi-tabs  161  can be commonly applied to all embodiments of the present invention. 
       FIGS. 6A and 6B  are enlarged cross-sectional views illustrating states before and after bending multi-tabs according to another embodiment of the present invention. 
     As shown in  FIGS. 6A and 6B , insulating layers  380  formed on surfaces of the multi-tab  161  may be spaced apart a predetermined distance apart from the first electrically active material layer  121   b . That is to say, the insulating layers  380  may not be necessarily brought into direct contact with the first electrically active material layer  121   b  but may be located only on areas needed to be insulated. 
     In more detail, the insulating layers  380  may be located only at predetermined areas of the multi-tabs  161  facing (corresponding to) a top end of the second electrode plate  123  spaced apart from the first electrically active material layer  121   b . That is to say, the insulating layers  380  may be located only at predetermined areas of the multi-tabs  161 , where the multi-tabs  161  are not electrically short-circuited to the second electrode plate  123  even if the separator  122  is punched by bent regions of the multi-tabs  161  at the time of bending the multi-tabs  161 . 
     The insulating layers  380  may be spaced, for example, but not limited to, about 0.1 mm to about 3 mm from the first electrically active material layer  121   b.    
     As described above, since the insulating layers  380  are located only at the predetermined areas of the multi-tabs  161  spaced apart from the first electrically active material layer  121   b , the manufacturing process of the multi-tabs  161  can be facilitated. That is to say, the insulating layers  380  are located on a non-coating portion of an electrode plate, followed by performing a notching process using a laser beam or a mold, thereby providing the multi-tabs  161 . As described above, since the insulating layers  380  are located only at the predetermined areas of the multi-tabs  161 , electrical/mechanical loads during the notching process using a laser beam or a mold can be reduced, thereby facilitating the manufacturing process. 
       FIGS. 7A and 7B  are enlarged cross-sectional views of multi-tabs according to another embodiment of the present invention. 
     As shown in  FIG. 7A , each of the multi-tabs  161  may have a substantially planar first surface  161   d , a substantially planar second surface  161   e  opposite to the first surface  161   d , a third surface  161   f  connecting first ends of the first and second surfaces  161   d  and  161   e , and a fourth surface  161   g  connecting second ends of the first and second surfaces  161   d  and  161   e  and opposite to the third surface  161   f . The insulating layers  280  may be located only on the first and second surfaces  161   d  and  161   e , which are relatively wide surfaces. That is to say, the third and fourth surfaces  161   f  and  161   g  of the multi-tab  161  may be exposed. 
     In other words, the insulating layers  280  are located on first and second surfaces of the non-coating portion, and the multi-tabs  161  are then formed by performing the notching (or cutting) process using a laser beam or a mold. Therefore, as described above, the insulating layers  280  may not be located on the third and fourth surfaces  161   f  and  161   g  of the multi-tab  161  but may be exposed. That is to say, one surface of each of the insulating layers  280  may be coplanar with the third surface  161   f  of the multi-tab  161 , and the other surface of the insulating layer  280  may be coplanar with the fourth surface  161   g  of the multi-tab  161 . 
     Meanwhile, as shown in  FIG. 7B , the insulating layers  280  may be located not only on the first and second surfaces  161   d  and  161   e , which are relatively wide surfaces, but also on the third and fourth surfaces  161   f  and  161   g , which are relatively narrow surfaces. That is to say, none of the first, second, third and fourth surfaces  161   d ,  161   e ,  161   f  and  161   g  of the multi-tab  161  may be exposed through the insulating layers  280 . 
     In other words, the insulating layers  280  are located on the first and second surfaces of the non-coating portion, and the multi-tabs  161  are then formed by performing the notching (or cutting) process using a laser beam or a mold. Therefore, as described above, the insulating layers  280  may be located not only on the first and second surfaces  161   d  and  161   e  but also on the third and fourth surfaces  161   f  and  161   g  of the multi-tab  161 . That is to say, during the notching process using a mold, a portion of the insulating layer  280  located on the first surface  161   d  or the second surface  161   e  is pushed to the third and fourth surfaces  161   f  and  161   g , so that the third and fourth surfaces  161   f  and  161   g  of the multi-tab  161  are covered by the insulating layer  280 . The insulating layers  280  located on the third and fourth surfaces  161   f  and  161   g  of the multi-tab  161  can also prevent electrical short circuits from occurring between the third and fourth surfaces  161   f  and  161   g  and the second electrode plate  123  through the above-described process. 
     Although the foregoing description has been made with regard to a case where the insulating layers  280  are formed on the surfaces of the multi-tabs  161 , it should be understood by one skilled in the art that the insulating layers  280  are located on the surfaces of the first and second multi-tabs  161 / 171  and/or  162 / 172 . Moreover, it should be understood by one skilled in the art that these features can be commonly applied to all embodiments of the present invention. 
     Referring to  FIGS. 8A to 8C , schematic views illustrating a manufacturing method of a secondary battery  100  having a structure for suppressing multi-tab short circuits according to an embodiment of the present invention are illustrated. 
     As shown in  FIG. 8A , the first electrode first multi-tab  161  and the second electrode first multi-tab  171  of the first electrode assembly  120 A are welded to the first electrode terminal  140 , that is, the first current collector plate  144 , and the second electrode terminal  150 , that is, the second current collector plate  154 , provided in the cap plate  130 , and the first electrode second multi-tab  162  and the second electrode second multi-tab  172  of the second electrode assembly  120 B are also welded to the first electrode terminal  140  and the second electrode terminal  150 , respectively. Here, the first electrode first multi-tab  161  and the second electrode first multi-tab  171  of the first electrode assembly  120 A, and the first electrode second multi-tab  162  and the second electrode second multi-tab  172  of the second electrode assembly  120 B, have yet to be bent. In addition, if the welding process is completed, the insulation plate  180  is placed on the cap plate  130 . That is to say, the insulation plate  180  is placed on the first electrode first multi-tab  161  and the first electrode second multi-tab  162 , which are positioned on the first current collector plate  144 , and the second electrode first multi-tab  171  and second electrode second multi-tab  172 , which are positioned on the second current collector plate  154 . 
     As shown in  FIG. 8B , the first and second electrode assemblies  120 A and  120 B are bent roughly at right angle from the cap plate  130 . Accordingly, the first and second multi-tabs  161  and  162  provided in the first and second electrode assemblies  120 A and  120 B are bent with the first regions  161   a  and  162   a , the second regions  161   b  and  162   b  and the third regions  161   c  and  162   c . In addition, as the result of the bending process, the insulation plate  180  may be substantially covered by the first and second electrode assemblies  120 A and  120 B, the first and second multi-tabs  161  and  162  and the cap plate  130 . In addition, as the result of the bending process, the first and second electrode assemblies  120 A and  120 B are brought into close contact with each other to be parallel with each other. 
     As shown in  FIG. 8C , the first and second electrode assemblies  120 A and  120 B being in close contact with each other are inserted into the case  110 . That is to say, until the cap plate  130  closes the case  110 , the first and second electrode assemblies  120 A and  120 B and the cap plate  130  are pushed into the case  110 . 
     Next, the cap plate  130  is welded to the case  110  to then be fixed, and an electrolytic solution is inserted into the case  110  through an electrolyte injection hole. However, this process may be omitted in a case of a solid battery requiring no electrolytic solution. 
     Here, as described above, according to various embodiments of the present invention, since the first and second multi-tabs  161  and  162  are located only at outer regions (or inner regions) of the first and second electrode assemblies  120 A and  120 B, as the result of the bending process, the first and second multi-tabs  161  and  162  are bent so as to be symmetrical with each other. Therefore, it is possible to prevent electrical short circuits between the first and second multi-tabs  161  and  162 , and the case, the cap plate and/or the first and second electrode assemblies, which have polarities opposite to the first and second multi-tabs  161  and  162  from occurring during or after the manufacture of the secondary battery  100 . 
     Referring to  FIG. 9 , a perspective view illustrating an example of a battery module using a secondary battery  100  having a structure for suppressing multi-tab short circuits according to an embodiment of the present invention is illustrated. 
     As shown in  FIG. 9 , multiple secondary batteries  100  are arranged in a line and multiple bus bars  510  are coupled to the multiple secondary batteries  100 , thereby completing the battery module  1000 . For example, a first electrode terminal  140  of one of the multiple secondary batteries  100  and a second electrode terminal  150  of another adjacent secondary battery  100  may be welded to each other using the bus bar  510 , thereby providing the battery module  1000  including the multiple secondary batteries  100  connected to one another in series. The bus bar  510  may be made of aluminum or an aluminum alloy, and a first terminal plate  131  of the first electrode terminal  140  and a second terminal plate  141  of the second electrode terminal  150  may also be made of aluminum or an aluminum alloy, thereby allowing the bus bar  510  to be easily welded to the first electrode terminal  140  and the second electrode terminal  150 . 
     Although the foregoing embodiments have been described to practice the secondary battery having a structure for suppressing multi-tab short circuits of the present invention, these embodiments are set forth for illustrative purposes and do not serve to limit the invention. Those skilled in the art will readily appreciate that many modifications and variations can be made, without departing from the spirit and scope of the invention as defined in the appended claims, and such modifications and variations are encompassed within the scope and spirit of the present invention.