Pouch exterior material, and secondary battery and secondary battery pack using the same

Abstract

To provide a pouch case, and a secondary battery and a secondary battery pack using the same.SOLUTION: A pouch case includes first and second accommodation portions formed to accommodate an electrode assembly, a sealing portion formed along an outer part of the pouch case to surround the first and second accommodation portions, and a connecting portion formed with the same depth as that of the first and second accommodation portions and configured to connect the first and second accommodation portions at a predetermined interval, where a protrusion protrudes toward the sealing portion at opposite ends of the connecting portion. Accordingly, in the pouch case, and a secondary battery and a secondary battery pack using the same, one side surface of the secondary battery has a perfect cooling structure, and thus an effect of holding the one side surface of the secondary battery closely to a cooling plate to maximize the cooling efficiency is achieved.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a pouch exterior material, and a secondary battery and a secondary battery pack using the same, and more particularly, to a pouch exterior material in which one side of a secondary battery using the pouch exterior material has a perfect cooling structure, so that one side of the secondary battery is in close contact with a cooling plate, thereby maximizing cooling efficiency and increasing energy density, and a secondary battery and a secondary battery pack using the same. [Background technology]

[0002] Generally, lithium secondary batteries are classified into can-type secondary batteries in which an electrode assembly is incorporated in a metal can and pouch-type secondary batteries in which an electrode assembly is incorporated in a pouch made of an aluminum laminate sheet, depending on the shape of the exterior material.

[0003] Lithium secondary batteries are widely used not only in small mobile devices but also in medium and large devices such as automobiles and power storage devices. In such cases, a large number of pouch-type secondary batteries, which are easy to stack and lightweight, are connected together in order to increase capacity and output.

[0004] However, when a battery module is constructed by stacking a number of pouch-type secondary batteries, heat released from the number of secondary batteries may accumulate, causing the temperature of the battery module to rise in a short period of time. Therefore, when constructing a battery module using a number of pouch-type secondary batteries, it is very important to ensure stable and effective cooling performance.

[0005] Therefore, recently, research has been conducted into a method of cooling a pouch-type secondary battery by directly contacting the side of the battery with a cooling plate as a cooling method that ensures efficient cooling performance and has a simple structure. However, at present, there are limitations to the shape of the pouch exterior material, and it has been difficult to effectively bring the side of the pouch-type secondary battery into close contact with a cooling plate.

[0006] FIG. 1 is an exploded perspective view of a pouch-type secondary battery according to the prior art.

[0007] Referring to FIG. 1, a pouch exterior material 10 of the prior art configured to provide a storage space for storing an electrode assembly 20 has a pair of storage sections formed as spaces independent of each other, each of the pair of storage sections having a width and length corresponding to the width and length of the electrode assembly 20 to be stored, and the sum of the depths of the pair of storage sections corresponds approximately to the thickness of the electrode assembly 20.

[0008] However, in the pouch-type secondary battery according to the prior art, a concave line may be formed in the length direction of the side surface on one side surface other than the three sides on which the pouch exterior material 10 is sealed. In this manner, the concave line formed on the side surface of the secondary battery makes it difficult for the side surface of the secondary battery to effectively contact the cooling plate, resulting in a problem of reduced cooling efficiency.

[0009] In order to solve the above problems, Patent Document 1 discloses a pouch exterior material in which a pair of storage sections are formed as a single space rather than separated as independent spaces. However, even when a pouch exterior material of this shape is used, it is not easy to fold the exterior material when packaging the electrode assembly, and it is difficult to uniformly form the side portion of the secondary battery that comes into contact with the cooling plate. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Korean Patent Publication No. 10-2007-0102768 Summary of the Invention [Problem to be solved by the invention]

[0011] Therefore, the present invention has been devised to solve the problems of the conventional technology, and aims to provide a pouch exterior material in which one side of a secondary battery using the pouch exterior material is uniformly formed to have a perfect cooling structure, and one side of the secondary battery is in close contact with a cooling plate to maximize cooling efficiency, and a secondary battery and a secondary battery pack using the same.

[0012] Another object of the present invention is to provide a pouch exterior material that can have a high energy density by forming the side portions of a secondary battery flat without protruding, thereby occupying a smaller space for the same battery capacity, and to provide a secondary battery and a secondary battery pack using the same.

[0013] The technical problems that the present invention aims to solve are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood from the following description by a person having ordinary skill in the art to which the present invention belongs. [Means for solving the problem]

[0014] In order to achieve the above-mentioned object, the pouch exterior material of the present invention is a pouch exterior material that stores and packages an electrode assembly including a number of electrode bodies stacked with separators in between, and is characterized in that it includes first and second storage sections formed to store the electrode assembly, a sealing section formed along the outside of the pouch exterior material so as to surround the first and second storage sections, and a connecting section formed to the same depth as the first and second storage sections and connecting the first and second storage sections at a predetermined interval, and both ends of the connecting section are formed with protrusions that protrude toward the sealing sections.

[0015] In the pouch exterior material of the present invention, it is preferable that the protrusion includes a top portion formed at a predetermined height from the bottom surface of the connecting portion, and an inclined portion formed and inclined from one end of the top portion toward the bottom surface of the connecting portion.

[0016] In the pouch exterior material according to the present invention, it is preferable that the inclined portion is connected to the bottom surface of the top portion and the connecting portion with a predetermined radius of curvature.

[0017] In the pouch exterior material according to the present invention, it is preferable that the top portion is formed at the same height as the sealed portion.

[0018] In the pouch exterior material of the invention, it is preferable that the first storage section and one side of the connecting section are connected along a first fold line, and the second storage section and the other side of the connecting section are connected along a second fold line, and the pouch exterior material is folded along the first and second fold lines to accommodate the electrode assembly.

[0019] In the pouch exterior material according to the present invention, the first and second folding lines are preferably spaced apart by a distance corresponding to a thickness of the electrode assembly.

[0020] In order to achieve the above-mentioned object, the secondary battery of the present invention includes the above-mentioned pouch exterior material and an electrode assembly including a plurality of electrode bodies stacked with a separator sandwiched therebetween, and the pouch exterior material is packaged by storing the electrode assembly in a storage space formed by folding the seal portion so that the first and second storage portions face each other.

[0021] In the secondary battery according to the present invention, it is preferable that the connection portion uniformly forms a side surface of the packaged secondary battery, and the sealing portion includes an extension portion protruding a predetermined length in a direction perpendicular to the side surface of the secondary battery from portions adjacent to both ends of the side surface of the secondary battery.

[0022] In order to achieve the above-mentioned objective, the secondary battery pack of the present invention is characterized by including one or more secondary batteries as described above, and a cooling plate having a first side surface, a second side surface opposite the first side surface, and an upper surface with which the side surfaces of the one or more secondary batteries are in surface contact.

[0023] In the secondary battery pack according to the present invention, it is preferable that the connection portion of the secondary battery uniformly forms a side surface of the packaged secondary battery, and the sealing portion of the secondary battery includes an extension portion protruding a predetermined length in a direction perpendicular to the side surface of the secondary battery from portions adjacent to both ends of the side surface of the secondary battery.

[0024] In the secondary battery pack of the present invention, it is preferable that a width between the first side surface and the second side surface of the cooling plate corresponds to a length of a connecting portion of the secondary battery.

[0025] In the secondary battery pack according to the present invention, it is preferable that a width between the first side and the second side of the cooling plate is greater than a length of the connecting portion of the secondary battery.

[0026] In the secondary battery pack according to the present invention, it is preferable that a step is formed on each of the first and second side surfaces of the cooling plate with a height greater than or equal to the predetermined length of the extension portion of the secondary battery.

[0027] In the secondary battery pack of the present invention, it is preferable that one or more grooves are formed on each of the first and second sides of the cooling plate to accommodate the extension portion of the secondary battery and to a depth deeper than or equal to a predetermined length of the extension portion. Effect of the Invention

[0028] The pouch exterior material according to the present invention, and the secondary battery and secondary battery pack using the same have an effect of maximizing cooling efficiency by having one side of the secondary battery be in close contact with a cooling plate, since one side of the secondary battery is uniformly formed to have a perfect cooling structure.

[0029] In addition, the pouch exterior material of the present invention, and the secondary battery and secondary battery pack using the same, have the effect of occupying a smaller space for the same battery capacity by forming the side portions of the secondary battery flat without protruding, thereby providing a high energy density. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is an exploded perspective view of a secondary battery according to the prior art. [Diagram 2] FIG. 1 is an exploded perspective view of a secondary battery according to the present invention. [Diagram 3] FIG. 2 is a plan view of a pouch exterior material according to the present invention. [Figure 4] 4 is a cross-sectional view taken along line AA' in FIG. [Diagram 5] FIG. 4 is a cross-sectional view taken along line BB′ in FIG. [Figure 6] 1 is a perspective view illustrating a secondary battery according to the present invention; [Figure 7] 1 is a first example of a secondary battery pack formed by combining a secondary battery and a cooling plate according to the present invention; [Figure 8] 8(a) and (b) are enlarged detailed views of FIG. [Figure 9] 11 is a second example of a secondary battery pack formed by combining a secondary battery and a cooling plate according to the present invention; FIG. [Figure 10] 9(a) and (b) are enlarged detailed views of FIG. [Figure 11] 11 is a third example of a secondary battery pack formed by combining a secondary battery and a cooling plate according to the present invention; FIG. [Figure 12] 11(a) and (b) are enlarged detailed views of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings, in which: The following detailed description is by way of example only and merely illustrates preferred embodiments of the present invention.

[0032] FIG. 2 is an exploded perspective view of a secondary battery 300 according to the present invention.

[0033] 2, a secondary battery 300 according to the present invention may include a pouch exterior material 100 and an electrode assembly 200 including a number of electrode bodies stacked with separators sandwiched therebetween. Here, the pouch exterior material 100 houses and surrounds the electrode assembly 200, and the electrode assembly 200 is packaged by sealing the sealing parts 150 that come into contact with each other.

[0034] First and second electrode tabs 220, 230 may be formed on both ends of the electrode assembly 200. Although the electrode tabs are formed on both sides of the electrode assembly 200 in FIG. 2, the secondary battery 300 of the present invention is not limited to this configuration of the electrode tabs, and it is also possible to arrange both the first and second electrode tabs 220, 230 on either side of the sealing portion 150.

[0035] Referring to FIG. 2, the pouch exterior material 100 according to the present invention may include first and second storage sections 110, 120 formed to store the electrode assembly 200, a sealing section 150 formed along the outside of the pouch exterior material 100 to surround the first and second storage sections 110, 120, and a connecting section 140 formed at the same depth as the first and second storage sections 110, 120 and connecting the first and second storage sections 110, 120 at a predetermined distance d, and is characterized in that protrusions 130 protruding toward the sealing section 150 are formed on both ends of the connecting section 140.

[0036] A pair of first and second storage sections 110, 120 for storing the electrode assembly 200 may be formed in the pouch exterior material 100. The first and second storage sections 110, 120 may be formed by pressing the inside of the pouch exterior material 100 into a concave shape in the pouch exterior material 100, for example by pressing the inside of the pouch exterior material 100. Here, each of the first and second storage sections 110, 120 has a size corresponding to the width and length of the electrode assembly 200, and the sum of the depths of the first and second storage sections 110, 120 may be formed to correspond to the thickness t of the electrode assembly 200.

[0037] The connecting part 140 is formed at the same depth as the first and second storage parts 110, 120, and is a component that connects the first and second storage parts 110, 120 at a predetermined distance d, and extends the bottom surfaces of the first and second storage parts 110, 120 to connect them to each other. Here, one side of the first storage part and the connecting part 140 are connected along a first folding line, and the other side of the second storage part and the connecting part 140 are connected along a second folding line. When the secondary battery 300 is constructed using the pouch exterior material 100 of the present invention, the pouch exterior material 100 can be folded along the first and second folding lines 101, 102 to accommodate the electrode assembly 200.

[0038] Therefore, since the connecting portion 140 can constitute the side portion 310 of the secondary battery 300 after the secondary battery 300 is assembled, the width of the connecting portion 140 can be determined so that the first and second folding lines 101, 102 are spaced apart by a predetermined distance d, which corresponds to the thickness t of the electrode assembly 200. The width of the connecting portion 140 is the predetermined distance d at which the first and second folding lines 101, 102 are spaced apart, and the predetermined distance d is preferably set to be substantially the same as the thickness t of the electrode assembly 200 as described above, but the width of the connecting portion 140 is not limited thereto, and may be formed to be smaller or larger than the thickness of the electrode assembly 200 as necessary.

[0039] The connecting portion 140 may have protrusions 130 formed on both ends thereof, protruding toward the sealing portion 150 .

[0040] The protrusion 130 is a component that enables both ends of the side portion 310 of the secondary battery 300 to be easily folded without distortion when the sealing portion 150 is folded to face the first and second storage portions 110, 120 so that the pouch outer casing 100 forms a storage space for storing the electrode assembly 200, and may be composed of a top portion 131 formed at a predetermined height from the bottom surface of the connecting portion 140, and an inclined portion 132 formed and inclined from one end of the top portion 131 to the bottom surface of the connecting portion 140.

[0041] The detailed shape of the protrusion 130 can be understood with reference to FIGS.

[0042] 3 is a plan view of a pouch exterior material 100 according to the present invention, FIG. 4 is a cross-sectional view taken along line AA' in FIG. 3, and FIG. 5 is a cross-sectional view taken along line BB' in FIG.

[0043] 4, the protrusion 130 may be formed to include a top portion 131 extending at the same height as the sealing portion 150, and an inclined portion 132 formed by inclining from one end of the top portion 131 to the bottom surface of the connecting portion 140. Also, as shown in FIG. 4, it is preferable that the inclined portion 132 is loosely connected to the top portion 131 and the bottom surface of the connecting portion 140 so as to have a predetermined radius of curvature when connected to the top portion 131 and the bottom surface of the connecting portion 140. In this way, by forming the protrusion 130 to be loosely connected to the sealing portion 150 and the connecting portion 140 without a discontinuous gradient, it is possible to obtain an effect of preventing the protrusion 130 located on the side portion 310 of the secondary battery 300 from being damaged or torn when the pouch exterior material 100 is folded.

[0044] Referring to FIG. 5, the protrusion 130 is formed in the connecting portion 140 that connects the first and second storage portions 110, 120 at a distance from each other, and it is preferable that the width of the protrusion 130 is formed to be smaller than the predetermined distance d between the first and second storage portions 110, 120.

[0045] Here, an example is described in which the top portion 131 of the protrusion 130 extends to the same height as the sealing portion 150 and the width of the protrusion 130 is formed to be smaller than a predetermined distance d. However, the height of the top portion 131 and the width of the protrusion 130 are not limited to this, and it is possible to adjust the height or width of the protrusion 130 depending on the thickness t and shape of the electrode assembly 200 or the material of the pouch exterior material 100.

[0046] FIG. 6 is a perspective view illustrating a secondary battery 300 according to the present invention.

[0047] A secondary battery 300 using the pouch exterior material 100 of the present invention can be constructed to include the pouch exterior material 100 of the present invention and an electrode assembly 200, and the pouch exterior material 100 is sealed along the seal portion 150 after the electrode assembly 200 is stored in a storage space formed by folding the seal portion 150 so that the first and second storage sections 110, 120 face each other.

[0048] Referring to FIG. 6, the connecting portion 140 of the pouch exterior material 100 uniformly forms the side portion 310 of the secondary battery 300, and dimples 320 recessed into the interior of the secondary battery 300 may be formed at both ends of the side portion 310 of the secondary battery 300 at positions corresponding to the protrusions 130.

[0049] The dimples 320 function to guide the seal portions 150 at both ends of the side portion 310 so that they can be easily folded when the pouch exterior material 100 is folded, and their size and shape can have various forms depending on the thickness t and shape of the electrode assembly 200 or the height or width of the protrusion 130, which is appropriately adjusted depending on the material of the pouch exterior material 100.

[0050] As shown in FIG. 6, the secondary battery 300 using the pouch exterior material 100 according to the present invention is characterized in that the side portion 310 has a flat and uniform shape without being generally concave or protruding.

[0051] As a result, the secondary battery 300 according to the present invention can have a perfect adhesion when the side portion 310 is in contact with the cooling plate 500 for cooling, and has a low thermal resistance and a high heat dissipation efficiency.

[0052] The secondary battery 300 using the pouch exterior material 100 of the present invention is characterized in that the side portion 310 has a flat shape without being generally concave or protruding, so that the secondary battery 300 of the present invention can have complete adhesion when the side portion 310 is brought into contact with the cooling plate 500 for cooling, and can have high heat dissipation efficiency with low thermal resistance.

[0053] In addition, since the side portion 310 of the secondary battery 300 of the present invention is formed uniformly without protruding, it takes up less space for the same battery capacity than if the side portion 310 were to be bent outward or have a separate sealed portion that would cause it to protrude, and therefore the secondary battery 300 of the present invention has the advantage of being able to have a high energy density.

[0054] In addition, the sealing portion 150 located at the portions adjacent to both ends of the side portion 310 of the secondary battery 300 may include an extension portion 151 that protrudes a predetermined length in a direction perpendicular to the side portion 310 of the secondary battery 300 during folding for packaging. As a result, a space may be formed between the extension portion 151 and the side portion 310 by the protruding length of the extension portion 151. Here, the length of the extension portion 151 may be several mm.

[0055] The extension portion 151 formed as described above can function to maintain or fix the position of the secondary battery 300 relative to the cooling plate 500 by forming a groove 520 or a step 510 capable of accommodating the extension portion 151 on the side of the cooling plate 500 when the secondary battery 300 of the present invention is combined with the cooling plate 500 to manufacture a secondary battery pack.

[0056] 7 to 12 are views relating to first to third examples in which a secondary battery 300 according to the present invention can be combined with a cooling plate 500 to constitute a secondary battery pack.

[0057] 7 and 8 are a first example of a secondary battery pack according to the present invention and an enlarged detailed view thereof.

[0058] 7, a plurality of secondary batteries 300 according to the present invention may be arranged on a cooling plate 500 to form a secondary battery pack. Here, the cooling plate 500 has a first side surface, a second side surface opposite to the first side surface, and an upper surface with which the side surface portions 310 of one or more secondary batteries 300 come into surface contact.

[0059] According to a first example of a secondary battery pack shown in Fig. 7, the width of the first and second sides of the cooling plate 500 may correspond to the length of the connection portion 140 of the secondary battery 300. Referring to Figs. 8(a) and 8(b), in this case, the cooling plate 500 may be sandwiched between the extension portions 151 of the secondary battery 300 when the upper surface of the cooling plate 500 is in close contact with the side portion 310 of the secondary battery 300.

[0060] With this structure, the movement of the secondary battery 300 in the longitudinal direction of the secondary battery 300 is restricted, preventing the secondary battery 300 from moving away from the cooling plate 500, thereby having the effect of maintaining the arrangement of the secondary battery 300 and the cooling plate 500.

[0061] 9 and 10 are a view showing a second example of a secondary battery pack according to the present invention and an enlarged detailed view thereof.

[0062] 9, the width of the first and second sides of the cooling plate 500 may be greater than the length of the connecting portion 140 of the secondary battery 300, and a step 510 may be formed on each of the first and second sides of the cooling plate 500 with a height greater than or equal to a predetermined protruding length of the extension portion 151 of the secondary battery 300. Referring to FIGS. 10(a) and 10(b), when the upper surface of the cooling plate 500 is in close contact with the side portion 310 of the secondary battery 300, the extension portion 151 of the secondary battery 300 may be placed on the step formed on the cooling plate 500.

[0063] This structure has the effect of restricting the movement of the secondary battery 300 in the length direction of the secondary battery 300, preventing the secondary battery 300 from moving away from the cooling plate 500, and maintaining the arrangement of the secondary battery 300 and the cooling plate 500. In addition, the secondary battery pack according to the second example has an effect of further increasing the cooling efficiency because the width of the cooling plate 500 is longer than that of the cooling plate 500 according to the first example.

[0064] 11 and 12 are a view showing a third example of a secondary battery pack according to the present invention and an enlarged detailed view thereof.

[0065] 11, the width of the first and second sides of the cooling plate 500 may be greater than the length of the connecting portion 140 of the secondary battery 300, and one or more grooves 520 may be formed on each of the first and second sides of the cooling plate 500 to a depth equal to or greater than a predetermined length of the extension portion 151 to accommodate the extension portion 151 of the secondary battery 300. Referring to FIGS. 12(a) and 12(b), when the upper surface of the cooling plate 500 is in close contact with the side portion 310 of the secondary battery 300, the extension portion 151 of the secondary battery 300 may be accommodated in the groove 520 formed in the cooling plate 500.

[0066] With this structure, the movement of the secondary battery 300 is restricted not only in the length direction of the secondary battery 300 but also in the direction perpendicular thereto, preventing the secondary battery 300 from moving away from the cooling plate 500, and maintaining the arrangement of the secondary battery 300 and the cooling plate 500. In addition, the width of the cooling plate 500 of the secondary battery pack according to the third example is wider than that of the cooling plate 500 of the first example, thereby further increasing the cooling efficiency.

[0067] To summarise the matters shown in Figures 7 to 12, in the secondary battery pack of the present invention, each of the multiple secondary batteries 300 arranged on the cooling plate 500 is arranged so that its side portion 310 is in close contact with the cooling plate 500, thereby enabling heat to be dissipated from the secondary batteries 300, and the extension portion 151 that protrudes a predetermined length from the side portion 310 of the secondary battery 300 restricts the movement of the secondary battery 300 in the lengthwise direction relative to the cooling plate 500, preventing it from moving out of position from the cooling plate 500, and has the effect of maintaining the arrangement of the secondary battery 300 and the cooling plate 500.

[0068] Although the present invention has been described and illustrated based on the preferred embodiment for illustrating the principles of the present invention, the present invention is not limited to the configuration and operation as so illustrated and described. A person skilled in the art to which the present invention belongs can understand that the present invention can be embodied in other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the above-described embodiments are illustrative in all respects and not limiting. The scope of the present invention is disclosed by the claims below, and all modifications or alterations derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. [Explanation of symbols]

[0069] 10, 100 pouch exterior material 20, 200 electrode assembly 101 First fold line 102 Second fold line 110, 120 First and second storage compartments 130 Protrusion 131 Top Section 132 Slope 140 Connection section 150 Seal part 151 Extension 220, 230 First and second electrode tabs 300 Secondary battery 310 Side part 320 Dimple 500 Cooling Plate 510 Steps 520 Groove

Claims

1. A pouch exterior material for housing and packaging an electrode assembly, a first receiving portion and a second receiving portion each formed to a predetermined depth for receiving the electrode assembly; A seal portion formed along the outer side of the pouch exterior material so as to surround the first storage portion and the second storage portion; a connecting portion formed between the first storage portion and the second storage portion and connecting the first storage portion and the second storage portion, The connecting portion is formed to the same depth as the first storage portion and the second storage portion, a protrusion protruding toward the sealed portion is formed on one end and the other end of the connecting portion adjacent to the sealed portion, the protrusion protruding toward the sealed portion.

2. Each of the protrusions is A top portion formed at a predetermined height from a bottom surface of the connecting portion; The pouch exterior material according to claim 1 , further comprising an inclined portion formed at an angle from one end of the top portion to a bottom surface of the connecting portion.

3. The pouch exterior material according to claim 2 , wherein the inclined portion is connected to the top portion and the bottom surface of the connecting portion with a predetermined radius of curvature.

4. The pouch exterior material according to claim 2 , wherein the top portion is formed to have the same height as the seal portion.

5. the first storage portion and one side of the connecting portion are connected along a first folding line; the second storage portion and the other side of the connecting portion are connected along a second folding line; The pouch exterior material according to claim 1 , wherein the pouch exterior material is folded along the first folding line and the second folding line to accommodate the electrode assembly.

6. The pouch exterior material according to claim 5 , wherein the first folding line and the second folding line are spaced apart by a distance corresponding to a thickness of the electrode assembly.

7. The pouch exterior material according to claim 5 , wherein each of the protrusions is formed between the first folding line and the second folding line.

8. The pouch exterior material according to claim 1 ; and an electrode assembly housed in the pouch exterior material, the pouch exterior material is configured to accommodate and package the electrode assembly in an accommodation space formed by folding the sealing portion so that the first accommodation portion and the second accommodation portion face each other.

9. the connecting portion uniformly forms a side surface of the packaged secondary battery, The secondary battery of claim 8 , wherein the sealing portion includes an extension portion that protrudes a predetermined length in a direction perpendicular to the side surface of the secondary battery from portions adjacent to both ends of the side surface of the secondary battery.

10. The secondary battery of claim 9, wherein the side surface of the secondary battery has a flat and uniform shape without being depressed or protruding as a whole.

11. The secondary battery according to claim 10 , wherein concave dimples are formed inside the secondary battery at both ends of a side surface of the secondary battery at positions corresponding to the protrusions.

Images