KR100893225B1 - Secondary Battery Having Improved Capacitance and Safety - Google Patents

Abstract

The present invention is a secondary battery in which an electrode assembly having a structure in which a plurality of electrode plates are stacked and interconnecting their electrode tabs with a separator interposed therebetween is built in a battery case, and each electrode plate is interconnected in a parallel manner. Tabs for interelectrode connection are formed, and one or more of the positive electrode plate and the negative electrode plate have a tab (electrode lead connection tab) for connecting to the electrode lead in addition to the interelectrode connection tab. The electrode tab and the electrode lead connecting tab is formed on the same side, and provides a secondary battery comprising the electrode assembly comprising such an electrode assembly.

Therefore, the electrode assembly according to the present invention may have a higher capacity than the same standard by maximizing the space inside the battery case, and the movement is suppressed when the drop or the external shock is applied to prevent the internal short circuit, thereby further improving the safety of the battery. There is an effect that can be improved.

Description

Secondary Battery Having Improved Capacitance and Safety}

1 is an exploded perspective view of a general structure of a conventional pouch type secondary battery;

FIG. 2 is a partially enlarged view of a top inside a battery case in which the positive electrode tabs are densely coupled in the secondary battery of FIG. 1 and connected to the positive electrode lead;

3 is a front perspective view of a state in which the secondary battery of FIG. 1 is assembled;

4 is an exploded perspective view of a secondary battery configured to include an electrode assembly according to one embodiment of the present invention;

5 is an exploded perspective view of a state before assembly of an electrode assembly in the secondary battery of FIG. 4;

FIG. 6A is a perspective view of a rivet for connecting tabs for connecting electrodes of an electrode assembly in the secondary battery of FIG. 4, and FIGS. 6B and 6C are schematic and vertical cross-sectional views of the upper side;

7 is a front perspective view of a state in which the secondary battery of FIG. 4 is assembled;

8 is an exploded perspective view of a state before assembly of an electrode assembly according to another exemplary embodiment of the present disclosure.

The present invention relates to an electrode assembly capable of improving capacity and safety, and more particularly, an electrode assembly having a structure in which a plurality of electrode plates are stacked with interconnecting separators and interconnecting electrode tabs are provided in a battery case. As a secondary battery built-in, each electrode plate is formed with tabs (tabs for inter-electrode connection) for interconnecting them in a parallel manner, one or two or more of the positive electrode plate and the negative electrode plate for the connection between the electrodes In addition to the tab, a tab (electrode lead connection tab) for connecting to the electrode lead is further formed, wherein the tab for connecting between the electrode and the electrode lead connection tab is formed on the same side will be.

As technology development and demand for mobile devices increase, the demand for batteries as energy sources is rapidly increasing, and accordingly, many studies on batteries that can meet various demands have been conducted.

Representatively, there is a high demand for rectangular secondary batteries and pouch secondary batteries, which can be applied to products such as mobile phones with a thin thickness in terms of shape of batteries, and lithium ion batteries with high energy density, discharge voltage, and output stability in terms of materials. There is a high demand for lithium secondary batteries such as lithium ion polymer batteries.

In addition, secondary batteries are classified according to the structure of the electrode assembly having a cathode / separation membrane / cathode structure. Typically, a long sheet-shaped cathode and cathode are wound around a separator. Jelly-roll (wound) electrode assembly, a plurality of positive and negative electrodes cut in units of a predetermined size stacked (stacked) electrode assembly sequentially stacked with a separator, the positive and negative electrodes of a predetermined unit And a stacked / folding electrode assembly having a structure in which a bi-cell or a full cell stacked in a state of being interposed therebetween is wound.

Recently, a pouch-type battery having a stacked or stacked / folding electrode assembly in a pouch-type battery case of an aluminum laminate sheet has attracted much attention due to its low manufacturing cost, low weight, and easy shape deformation. And its usage is gradually increasing.

FIG. 1 is a schematic exploded perspective view of a general structure of a conventional representative pouch type secondary battery.

Referring to FIG. 1, the pouch type secondary battery 10 may include an electrode assembly 30, electrode tabs 40 and 50 extending from the electrode assembly 30, and electrodes welded to the electrode tabs 40 and 50. It comprises a lead (60, 70), and a battery case 20 for receiving the electrode assembly.

The electrode assembly 30 is a power generator in which a positive electrode and a negative electrode are sequentially stacked in a state where a separator is interposed therebetween, and has a stack type or a stack / fold type structure. The electrode tabs 40, 50 extend from each electrode plate of the electrode assembly 30, and the electrode leads 60, 70 may include a plurality of electrode tabs 40, 50 extending from each electrode plate, for example, Each is electrically connected by welding, and a part of the battery case 20 is exposed to the outside. In addition, an insulating film 80 is attached to a portion of the upper and lower surfaces of the electrode leads 60 and 70 in order to increase the sealing degree with the battery case 20 and to secure an electrical insulating state.

The case 20 is made of an aluminum laminate sheet, provides a space for accommodating the electrode assembly 30, and has a pouch shape as a whole. In the case of the stacked electrode assembly 30 as shown in FIG. 1, the plurality of positive electrode tabs 40 and the plurality of negative electrode tabs 50 may be coupled together to the electrode leads 60 and 70. The upper end is spaced apart from the electrode assembly 30.

FIG. 2 is a partially enlarged view of an upper portion of a battery case connected to a cathode lead by combining positively connected tabs of the secondary battery of FIG. 1, and FIG. 3 is a front view of the assembled secondary battery of FIG. 1. Perspective view is shown.

Referring to these drawings, the plurality of positive electrode tabs 40 extending from the positive electrode current collector 41 of the electrode assembly 30 protrude from the positive electrode lead, for example, in the form of a welded portion integrally joined by welding. Connected to 60. The positive lead 60 is sealed by the battery case 20 with the opposite end 61 to which the positive electrode tab welding part is connected is exposed. Since the plurality of positive electrode tabs 40 are integrally coupled to form a welded portion, the inner upper end of the battery case 20 is spaced apart from the upper surface of the electrode assembly 30 by a predetermined distance, and the positive electrode tabs 40 of the welded portion are formed. Is bent in a substantially V shape. Therefore, the coupling region between the electrode tabs and the electrode lead is also referred to as a V-forming region.

However, these V-forming sites have a number of problems in terms of battery capacity and safety. First, since the capacity of the battery is substantially determined by the size of the electrode assembly 30, the presence of the V-forming portion limits the size of the electrode assembly 30 embedded in the battery case 20, and thus the capacity of the battery. Results in a decrease. That is, as shown in Figure 3, the distance (L ₁ ) between the top surface of the electrode assembly 30 and the insulating film 80 is very large, it is inevitable to reduce the size of the electrode assembly 30 by such a distance.

In addition, when the battery falls to its upper end, i.e., the positive lead 60, or when a physical external force is applied to the upper end of the battery, the electrode assembly 30 moves to the upper end of the inner surface of the battery case 20, or Since the negative electrode of the electrode assembly 30 is crushed to contact the positive electrode tab 42 or the positive electrode lead 61 and cause an internal short circuit, the safety of the battery is greatly reduced.

In order to solve the problem caused by the V-forming part, Japanese Patent Application Laid-Open No. 2002-141055 discloses that tabs for connecting electrodes in a stacked electrode assembly are formed on one side of each electrode plate and interconnected inside the case. Disclosed is a technique of forming an electrode lead, which is partially protruded out of the case, to a predetermined portion, rather than one side where the tabs are formed, for electrical connection with the device. However, in the above technology, a space for bending the electrode lead and a space for connecting the tabs are separately required in the case, thereby creating an unnecessary dead space, thereby causing an adverse effect of increasing the volume of the battery. .

Accordingly, an object of the present invention is to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

An object of the present invention to provide an electrode assembly having a higher capacity than the same standard by utilizing the space in the battery case to the maximum.

Another object of the present invention is to provide an electrode assembly that can further improve the safety of the battery by preventing the internal short-circuit is prevented by movement inside the battery case when the drop or external shock is applied.

Still another object of the present invention is to provide a secondary battery comprising such an electrode assembly.

An electrode assembly according to the present invention for achieving the above object is a secondary battery in which an electrode assembly having a structure in which a plurality of electrode plates are stacked and interconnecting electrode tabs thereof with a separator interposed therebetween is embedded in a battery case. Each electrode plate is formed with tabs (inter-electrode connection tabs) for interconnecting them in a parallel manner, and one or more of the positive and negative electrode plates are connected to an electrode lead in addition to the tab for inter-electrode connection. A tab (electrode lead connection tab) is further formed, and the inter-electrode connection tab and the electrode lead connection tab are formed on the same side.

Therefore, in the electrode assembly according to the present invention, the tabs for inter-electrode connection and the electrode leads and the electrode lead connection tabs are connected to each other and positioned in close contact with the same side of the electrode assembly, thereby minimizing space for their formation. By increasing the capacity of the battery case compared to the same standard, and close to the inner surface of the battery case to the side formed with the connection portion, the movement is suppressed to ensure more excellent safety when applying an external force such as a drop or an external impact Can be.

The electrode assembly is not particularly limited as long as it is a structure that connects a plurality of electrode tabs to form an anode and a cathode, and preferably includes a stack type structure and a stack / fold type structure. Details of the electrode assembly of the stack / foldable structure are disclosed in Korean Patent Application Publication Nos. 2001-0082058, 2001-0082059, and 2001-0082060, which are described in the context of the present invention. Incorporated by reference.

In some cases, the electrode lead connection tab may be formed on at least two positive electrode plates and at least two negative electrode plates among the electrode plates constituting the electrode assembly, but more preferably, only one positive electrode plate and one negative electrode plate. Each is formed. When two or more positive electrode plates and negative electrode plates are formed with tabs for electrode lead connection, a separate process for connecting the electrode lead connection tabs should be added, and the volume increases when the electrode lead connection tabs are in close contact. This is because the space occupied inside the battery case becomes wider. Therefore, it is particularly preferable that the electrode assembly includes one positive electrode plate and one negative electrode plate each having a tab for inter-electrode connection and a tab for electrode lead connection.

In addition, in the present invention, since the electrode lead connection tab performs a connection to the electrode lead, it may be configured to a somewhat larger size than the inter-electrode connection tabs.

Hereinafter, for convenience of description, one side of the electrode plate to which the electrode lead is connected is shown as the upper side and / or lower side. At this time, the upper side and the lower side means both sides facing each electrode plate, but the electrode plate is not limited to the polygonal structure including the side.

In one preferred embodiment, the electrode lead connection tabs are formed together on the upper side of the positive electrode plate and the negative electrode plate, in this case, the inter-electrode connection tabs are formed to face each other near each of the corners of the upper side There may be. At this time, the electrode lead connection tab (electrode lead connection positive electrode tab) formed on the positive electrode plate and the electrode lead connection tab (electrode lead connection negative electrode tab) formed on the negative electrode plate, the process of connecting the electrode lead can be made easily. It is preferable that the upper sides are spaced apart from each other at predetermined intervals.

In the above example, the inter-electrode connection tab is preferably formed near the edge adjacent to the electrode lead connection tab formed on the same side thereof. That is, when the positive electrode tab for electrode lead connection is formed on the right side of the upper side of the positive electrode plate relatively, and the negative electrode tab for electrode lead connection is formed on the left side of the upper side of the negative electrode plate relatively, the connection between electrodes formed on the positive electrode plate The tab (anode tab for interelectrode connection) is formed near the right edge of the upper side of the positive electrode plate, and the interelectrode connection tab (cathode tab for interelectrode connection) formed on the negative electrode plate is located near the left edge of the upper side of the negative electrode plate. It may be formed in. This is to prevent a short circuit during the connection work of the inter-electrode connection tabs.

In another preferred example, the electrode lead connection tabs are formed opposite to each other at the upper side and the lower side of the positive electrode plate and the negative electrode plate, in this case, the tab for inter-electrode connection is a diagonal position of the upper side and the lower side It may be formed to face each other near the two corners of the. For example, if the positive electrode tab for electrode lead connection is formed in the center of the upper side of the positive electrode plate and the negative electrode tab for electrode lead connection is formed in the center of the lower side of the negative electrode plate, the positive electrode tab for inter-electrode connection is formed in the positive electrode plate. It is formed on the right side of the upper side, the negative electrode tab for inter-electrode connection may be formed on the left side of the lower side of the negative electrode plate. This is to facilitate the connection work between the tabs for inter-electrode connection tabs and the electrode lead connection tabs and electrode leads, as described above, and to prevent a short circuit during operation.

In the present invention, the inter-electrode connection tabs may be interconnected in various ways such as welding, soldering, mechanical fastening members, and the like, and preferably, may be interconnected by a hollow structure rivet into which a plurality of tabs may be inserted.

In the above structure, the rivet is preferably a tapered structure in the direction in which the inter-electrode connection tabs are inserted in a vertical cross section, and is compressed in the stacking direction of the tabs in a state in which the inter-electrode connection tabs are inserted in the hollow shape. An electrical connection can be made with the fastening.

Specifically, the rivet has an elliptical shape in the shape of the end surface A in the direction in which the inter-electrode connection tabs are inserted, and the shape of the end surface (opposite end surface B) opposite to the end surface is relatively more. It has a flat oval shape, and the major axis of the end surface A and the major axis of the opposite end surface B are substantially the same size. Therefore, the vertical cross-sectional shape with respect to the short axis of an ellipse has comprised the taper structure. The rivet of this structure can easily insert and focus a plurality of inter-electrode connection tabs in the direction of the end surface (A) of which the length of the short axis is relatively large. Can be done.

Such rivets solve the problem of welding, for example, for electrical connection, in addition to the above effects. While the tab for inter-electrode connection as in the present invention is preferably as small as possible in terms of utilization of the internal space of the battery, the welding site is close to the electrode active material when performing welding, and thus, deterioration of the electrode active material, Increased risk of internal short circuit. However, the use of the rivet can solve the problem of such high heat generation.

In general, since the electrode assembly uses a separator having a larger size than the anode and the cathode in order to prevent a short circuit, the outer circumferential surface of the electrode assembly is substantially surrounded by separators extending longer than the anode and the cathode. Therefore, the portion where the tabs for the inter-electrode connection are interconnected is bent and close to the side of the electrode assembly does not cause a short circuit.

In the present invention, in order to further reduce the possibility of such a short circuit due to the bending and close contact at the connection portion of the tab for connecting the electrodes, the size of the separator of the electrode assembly is larger than in the conventional electrode assembly, or as an insulating member such as an insulating film The connection portions of the inter-electrode connection tabs may be applied in advance and then bent to closely contact the side surfaces of the electrode assembly. In particular, as in the above example of the preferred structure, when connecting tabs for inter-electrode connection using a rivet, it is preferable to apply an insulating member to the outer surface of the rivet.

As described above, since the connection portion of the inter-electrode connection tabs and the electrode lead connection tab and the electrode lead are respectively in close contact with the side of the electrode assembly, there is no dead space as a whole or at least The battery having a compact structure can be completed by minimizing dead space, and the side of the electrode assembly is in close contact with the inner surface of the battery case, thereby preventing the electrode assembly from moving even when an external force is applied.

The present invention also provides a secondary battery comprising such an electrode assembly.

The battery according to the present invention can be preferably used in a so-called lithium ion polymer battery in which the lithium electrolyte is impregnated in the electrode assembly in the form of a gel.

In addition, the battery according to the present invention can be preferably applied to a pouch type battery in which an electrode assembly is built in a pouch type case of a laminate sheet, specifically, an aluminum laminate sheet, including a metal layer and a resin layer.

Hereinafter, although described with reference to the drawings according to an embodiment of the present invention, this is for easier understanding of the present invention, the scope of the present invention is not limited thereto.

4 is an exploded perspective view schematically illustrating a secondary battery including an electrode assembly according to an embodiment of the present invention.

Referring to FIG. 4, in the secondary battery 600, positive electrode tabs 130, 131, 132..., And negative electrode tabs 140, 141, 142... An electrode assembly 100 in which the positive electrode tab 101 and the negative electrode tab 102 are connected to the positive electrode lead 300 and the negative electrode lead 301, respectively, and a battery case capable of accommodating the electrode assembly 100. It consists of 200.

The electrode assembly 100 has a positive electrode plate and a negative electrode tab 102 for connecting electrode leads and an electrode for connecting electrode leads, respectively, having a positive electrode tab 101 for connecting an electrode lead and a positive electrode tab 130 for connecting between electrodes formed on an uppermost layer thereof. Each of the cathode tabs 140 includes one cathode plate on which each is formed. The specific structure of the electrode assembly can be more easily confirmed in FIG. 5 in which an exploded perspective view thereof is schematically shown.

Referring to FIG. 5, the electrode assembly 100 includes one positive electrode plate 110 having a positive electrode tab 101 for connecting electrode leads and a positive electrode tab 130 for connecting electrodes, and a negative electrode tab for connecting electrode leads. One cathode plate 120 having the 102 and the cathode tab 140 for the interelectrode connection formed thereon, and a plurality of the anode plates having only the anode tabs 131, 132. 111, 112... And a plurality of negative electrode plates 121 and 122 having only the negative electrode tabs 141 and 142 for connecting between electrodes are sequentially manufactured by using the separator 150.

The positive electrode tab 101 for connecting the electrode leads in one positive electrode plate 110 is formed on the left side of the upper side of the positive electrode plate 110, and the negative electrode tab 102 for connecting the electrode leads in one negative electrode plate 120 is provided. The right side of the upper side of the negative electrode plate 120 is formed. In addition, the positive electrode tabs 130, 131, 132 ... for inter-electrode connection are formed near the left edge at each upper side of the positive electrode plates 110, 111, 112 ..., and the negative electrode tabs for inter-electrode connection 140, 141, 142,... Are formed near the right edges at the upper sides of the negative electrode plates 120, 121, 122. Thus, between the positive electrode tabs 130, 131, 132... And the negative electrode tabs 140, 141, 142 ... for inter-electrode connection, and the positive electrode tab 101 and negative electrode tab 102 for electrode lead connection. The connection work between the electrode leads 300 and 301 can be easily performed, and a short circuit can be prevented during the work.

Referring to FIG. 4 again, the positive electrode tabs 131, 132... And the negative electrode tabs 141, 142 ..., Which are connected to each other by the rivet 400 are connected to the top surface of the electrode assembly. 160). At this time, the upper surface of the electrode assembly 100 in a state in which the conductive metal material rivet 400 is connected to the positive electrode tabs 131, 132... And the negative electrode tabs 141, 142. In order to prevent the short circuit caused by being connected to the 160, the rivet 400 is in close contact with the upper surface 160 while wrapped with the insulating film 500. For ease of understanding, FIG. 4 shows the mounted shape of the rivet 400 as a perspective view. The structure of the rivet 400 interconnecting the positive electrode tabs 131, 132... And the negative electrode tabs 141, 142 ... for inter-electrode connection is shown in its perspective and upper schematic diagrams and in cross-sectional view. It can be more easily confirmed in 6a to 6c.

First, referring to FIGS. 6A and 6B, the rivet 500 is a hollow cylindrical structure, and includes a top surface 510 made of a hollow elliptic structure and a bottom surface 520 made of a hollow circular structure. In this case, the long axis R ₁ of the lower surface 520 is about the same as or slightly larger than the long axis r ₁ of the upper surface 510. On the other hand, since the short axis r ₂ of the upper surface 510 is much smaller than the short axis R ₂ of the lower surface 520, the rivet 500 is tapered downward in the overall shape. . This structure can be more easily seen in FIG. 6C, which is shown as a vertical cross-sectional view of FIG. 6A.

Referring to FIG. 6C, the rivet 500 has a tapered structure in a vertical cross section based on the short axis of the top surface 510. By this structure, the positive electrode tabs 140, 141, 142 ... for inter-electrode connection can be easily inserted into the inside of the rivet 500, by compressing the rivet 500 in the direction of the arrow in the inserted state. It is fixed and connected reliably. The rivet 500 is not particularly limited as long as it is a material having variability. For example, the rivet 500 may be made of nickel, copper, lead, or an alloy thereof. Therefore, if both sides are compressed in the state where the positive electrode tabs are inserted into its hollow interior as in FIG. 6C, the compressed state can be stably maintained.

Referring back to FIG. 4, in the state where the electrode assembly 100 is mounted on the accommodating portion 210 of the battery case 200, the positive electrode tab 101 and the negative electrode tab 102 for connecting the electrode leads are not bent. The positive electrode plate 110 and the negative electrode plate 120, in which two electrode tabs 101, 130; 102, 140 are formed, respectively, may be directly positioned on the upper contact portion of the battery case 200. Located on the top floor of 100).

FIG. 7 schematically illustrates a front perspective view of the assembled state of the secondary battery of FIG. 4.

Referring to FIG. 7, the secondary battery 600 greatly reduces the distance L ₂ between the top surface of the electrode assembly 100 and the insulating film 320, thereby comparing the electrode assembly with the same standard of the battery case 200. The size of the battery can be increased by increasing the size of the (100). In addition, since the secondary battery 600 does not have a space in which the electrode assembly 100 can move inside the battery case 200, the secondary battery 600 may further secure safety against short circuits during dropping and external impact.

8 is an exploded perspective view schematically showing a state before assembly of the electrode assembly according to another embodiment of the present invention.

Referring to FIG. 8, the electrode assembly 700 includes one positive electrode plate 710 and a negative electrode tab for connecting electrode leads, respectively, in which a positive electrode tab 701 for connecting electrode leads and a positive electrode tab 730 for connecting between electrodes are formed. 702 and one cathode plate 720 each having a negative electrode tab 740 for inter-electrode connection, and a plurality of positive electrode plates each having only positive electrode tabs 731, 732. 711, 712 ... and a plurality of negative electrode plates 721, 722 having only the negative electrode tabs 741, 742 for connecting between electrodes are sequentially manufactured by using the separator 750.

The positive electrode tab 701 for connecting electrode leads in one positive electrode plate 710 is formed at the center of the lower side of the positive electrode plate 710, and the negative electrode tab 702 for connecting electrode leads in one negative electrode plate 720 is provided. The center of the upper side of the negative electrode plate 720 is formed. In addition, the positive electrode tabs 730, 731, 732 ... for inter-electrode connection are formed near the left edge at each lower side of the positive electrode plates 710, 711, 712 ..., and the negative electrode tabs for inter-electrode connection 740, 741, 742,... Are formed near the right edges at the upper edges of the cathode plates 720, 721, 722. Thus, as described above, between the positive electrode tabs 730, 731, 732 ... for the electrode connection and the negative electrode tabs 740, 741, 742 ... and the positive electrode tab 701 for electrode lead connection, and A connection operation between the negative electrode tab 702 and the electrode leads 300 and 301 can be easily performed, and a short circuit can be prevented during the operation.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are provided to illustrate the present invention, and the scope of the present invention is not limited thereto.

Example 1

95% by weight of LiCoO ₂ , 2.5% by weight of Super-P (conductor) and 2.5% by weight of PVdF (binder) were added to NMP (N-methyl-2-pyrrolidone) as a cathode active material to prepare a cathode mixture slurry. 95% by weight of artificial graphite, 1% by weight of Super-P (conductive agent) and 4% by weight of PVdF (binder) were added to NMP as a solvent to prepare a negative electrode mixture slurry, which was applied to aluminum foil and copper foil, respectively. .

The aluminum foil and the copper foil are respectively cut into a plurality of plates in which one electrode tab is formed on one side, and one plate in which two electrode tabs are formed on one side, as shown in FIG. 5. The plates were each prepared. Then, using Celgard ^TM (TONEN) as a separator, an electrode assembly was manufactured by sequentially stacking the positive electrode plate and the negative electrode plate on which the two electrode tabs were formed and the remaining positive electrode plate and the negative electrode plate in sequence. . After mounting the electrode assembly in a pouch-type battery case, as shown in Figure 4, the electrolyte was injected to complete the battery.

Comparative Example 1

Except for fabricating an electrode assembly using a positive electrode plate and a negative electrode plate with an electrode tab formed on one side and mounted in a battery case in the same structure as in Figure 1, the battery in the same manner as in Example 1 To complete.

Experimental Example 1

In each of the 20 prepared batteries in Example 1 and Comparative Example 1, the battery drop experiment was repeated 50 times in the direction of the electrode lead protruding direction of the battery at a height of 1.5 m, and then confirmed whether the short circuit. The results are shown in Table 1 below.

TABLE 1

As shown in Table 1, the cells of Example 1 according to the present invention did not cause a short circuit in all 20 cells in the front drop experiment. That is, since there is no empty space between the inner surface of the battery case and the electrode assembly, a short circuit due to the movement of the electrode assembly when the battery is dropped does not occur. On the other hand, the batteries of Comparative Example 1 were short-circuited in many batteries.

In addition, in terms of the capacity of the battery, when the battery case of the same size is used, the battery of Example 1 can increase the size of the electrode plate to which the active material is applied by about 10% compared to the battery of Comparative Example 1 Confirmed. Therefore, the capacity of the battery can be increased by that amount.

As described above, the electrode assembly according to the present invention can have a high capacity compared to the same standard by maximizing the space inside the battery case, by preventing movement or the internal short circuit is suppressed when the battery falls or the external shock applied, There is an effect that can further improve the safety of the battery.

Those skilled in the art to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

Claims (14)

A secondary battery in which an electrode assembly having a structure in which a plurality of electrode plates are stacked and interconnecting electrode tabs with a separator interposed therebetween is embedded in a battery case. Each electrode plate has a tab for interconnecting them in a parallel manner. (Electrode connection tabs) are formed, and one or two or more of the positive electrode plate and the negative electrode plate are further formed with a tab (electrode lead connection tab) for connecting to the electrode lead in addition to the inter-electrode connection tab And the tabs for connecting the electrodes and the tabs for connecting the electrode leads are formed on the same side, and the tabs for connecting the electrodes are interconnected by a rivet of a hollow structure into which they can be inserted. . The electrode assembly of claim 1, wherein the electrode assembly has a stack type or a stack / fold type structure. The electrode assembly of claim 1, wherein the electrode lead connection tab is formed only on one positive electrode plate and one negative electrode plate of the plurality of electrode plates constituting the electrode assembly. The method of claim 1, wherein the electrode lead connection tabs are formed together at the upper sides of the positive electrode plate and the negative electrode plate, and the inter-electrode connection tabs are formed to face each other in the vicinity of both corners of the upper side. Electrode assembly characterized in that. 5. The electrode assembly according to claim 4, wherein the inter-electrode connection tab is formed near an edge adjacent to the electrode lead connection tab formed on the same side thereof. According to claim 1, wherein the electrode lead connection tabs are formed opposite to each other at the upper side and the lower side of the positive electrode plate and the negative electrode plate, the tab for inter-electrode connection two of the diagonal position of the upper side and the lower side An electrode assembly, which is formed to face each other in the vicinity of the corner. delete The method of claim 1, wherein the rivet has a tapered structure in a direction in which the inter-electrode connection tabs are inserted in a vertical cross section and is compressed in a stacking direction of the tabs in a state where the inter-electrode connection tabs are inserted. Electrode assembly. The electrode assembly of claim 1, wherein after the connection of the connection tabs between the electrodes, the tab connection portion is coated with an insulating member and then bent to be in close contact with the side of the electrode assembly. The electrode assembly according to claim 9, wherein the tab connecting portion is wrapped with an insulating film as the insulating member. A secondary battery comprising the electrode assembly according to any one of claims 1 to 6 and 8 to 10. The secondary battery of claim 11, wherein the secondary battery is a lithium ion polymer battery. The secondary battery of claim 11, wherein the battery case is a pouch type case of a laminate sheet including a metal layer and a resin layer. The secondary battery of claim 13, wherein the sheet is an aluminum laminate sheet.

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