Secondary battery

Abstract

To provide a secondary battery which can be manufactured by a simple assembling operation, and has a good operability at assembling.SOLUTION: A bag body 40 includes: two side surface parts 41 and 42; an end side surface part 43, 44 that is formed by folding an end part of an insulation film constructing the one side surface part 42; a bottom surface part 45 that blocks a bottom; a guide part 46, 47 that is formed by folding the end part of the insulation film constructing one of the end side surface parts 43 and 44 toward a front surface 41a of the other side surface part 41; a cover part 48, 49 that is formed by folding an edge of the insulation film constructing the bottom surface part 45 toward a front surface 43a, 44a of one of the end side surface parts 43 and 44; and a hypotenuse part 46a, 47a that couples a start point and a termination point and is inclined.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a secondary battery.

Background Art

[0002] Conventionally, as a secondary battery used in an electric vehicle having a motor as a drive source such as an electric vehicle or a hybrid vehicle, for example, a power storage device disclosed in Patent Document 1 has been proposed.

[0003] The power storage device described in Patent Document 1 has a configuration in which an electrode assembly housed in a bottomed rectangular tube-shaped insulating film is housed in a case body, and the space between the electrode assembly and the case body is insulated by the insulating film. In this power storage device, the insulating film is assembled into a predetermined shape in advance, and is housed in the case body in a state where predetermined portions of the insulating film are adhered to each other.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, as described above, the insulating film in the power storage device described in Patent Document 1 is assembled into a predetermined shape using adhesion or the like at the time of assembling the power storage device, and then housed in the case body. Therefore, when assembling the power storage device, it is necessary to perform the assembling work and the adhesion work of the insulating film, and there is room for improvement in terms of simplifying the assembling work.

[0006] On the one hand, as a method for simplifying the assembly work of a power storage device, there is a method of inserting an insulating film into a case body so that it can be folded into a predetermined shape during assembly. By using this method, since it is not necessary to pre-assemble the insulating film using adhesion or the like, the assembly work of the power storage device can be simplified.

[0007] However, when using the above method, there is a possibility that the insulating film may get caught on the case body during insertion, which may cause problems such as taking time for the work, damage to the insulating film, or the insulating film not being folded into a predetermined shape. Therefore, there is room for improvement in terms of workability during assembly.

[0008] The present invention has been made in view of the above circumstances, and an object thereof is to provide a secondary battery that can be manufactured with a simple assembly work and has good workability during assembly.

Means for Solving the Problems

[0009] The characteristic configuration of the secondary battery according to the present invention for achieving the above object is a housing having an opening, a lid body that seals the opening of the housing, an electrode body that is attached to the lid body via a battery terminal and is housed in the housing, a bag body that is disposed inside the housing and insulates between the housing and the electrode body, and the bag body is formed by folding an insulating film, has two opposing side portions, at least one of which has two end side portions formed by bending the end of the insulating film that constitutes one of the two side portions, a bottom surface portion that closes the bottom, a guide portion formed by bending the end of the insulating film that constitutes one of the end side portions toward the surface of the other side portion, and a cover portion formed by bending the edge of the insulating film that constitutes the bottom surface portion toward the surface of one of the end side portions. In a direction perpendicular to the surface of one of the end side faces in a state where the bag body is housed in the housing, a starting point is located at a position overlapping the cover portion, and an end point is located above the starting point on the edge of the insulating film located on the opposite side of the boundary with one of the end side faces in the guide portion, and an inclined hypotenuse portion connecting the starting point and the end point is formed.

[0010] According to the above characteristic configuration, when the bag body is housed in the housing, the cover portion contacts the housing and is bent toward the surface of the end side face, and the end side face is folded toward the electrode body side in a form pushed by the cover portion. Further, due to the formation of the hypotenuse portion, the guide portion and the end side face can be folded without being caught by the housing while the hypotenuse portion contacts the housing. Therefore, the secondary battery can be smoothly assembled without previously forming the bag body using adhesion or the like. That is, the secondary battery having the above characteristic configuration can be manufactured with a simple assembling operation, and the workability during assembly is also good.

[0011] A further characteristic configuration of the secondary battery according to the present invention is In a view in a direction perpendicular to the surface of one of the end side faces, a gap is formed between one of the end side faces and the bottom face, The cover portion covers the gap in a view in a direction perpendicular to the surface of one of the end side faces, The length from the boundary line with the bottom face in the cover portion to the edge on the opposite side of the boundary line is longer than the width of the gap in the height direction of the secondary battery.

[0012] According to the above characteristic configuration, since a gap covered by the cover portion is formed between the end side face and the bottom face, while preventing conduction between the electrode body and the housing through the gap, the electrolyte can flow back and forth between the inside and outside of the bag body through the gap. Therefore, the electrolyte is easily supplied to the electrode body in the bag body, and the amount of the electrolyte in the bag body is easily adjusted in accordance with the expansion and contraction of the electrode body accompanying charge and discharge.

[0013] A further characteristic configuration of the secondary battery according to the present invention is The electrode body is formed by laminating a positive electrode material and a negative electrode material with a separator therebetween. The two end side portions of the bag body face an end face parallel to the lamination direction of the electrode body.

[0014] According to the above characteristic configuration, the electrolyte is easily supplied to the vicinity of the end face of the electrode body through the gap, and the amount of electrolyte that can penetrate from the end face of the electrode body into the interior increases, so that the electrolyte can be effectively utilized.

[0015] The width of the gap is greater than 0% and 50% or less of the length of the cover portion.

[0016] According to the above characteristic configuration, while enabling the electrolyte to flow back and forth between the inside and outside of the bag body through the gap, the electrical connection between the electrode body and the housing through the gap can be preferably prevented.

Advantages of the Invention

[0017] As described above, according to the present invention, it is possible to provide a secondary battery that can be manufactured with a simple assembly operation and has good workability during assembly.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0019] Hereinafter, a secondary battery according to an embodiment of the present invention will be described with reference to the drawings. In the following, a mode in which the secondary battery is a lithium-ion secondary battery will be described as an example. Also, in the following, for the sake of clarity, each description and each drawing are appropriately simplified.

[0020] 〔Outline of Secondary Battery 1〕 FIG. 1 is an exploded perspective view of the secondary battery according to the present embodiment. FIG. 2 is a cross-sectional view showing the schematic configuration of the secondary battery according to the present embodiment. In the following description, the direction parallel to the height direction of the secondary battery 1 is defined as the Z-axis direction, the direction parallel to the longitudinal direction of the electrode body 20 is defined as the X-axis direction, and the direction parallel to the thickness direction of the electrode body 20 is defined as the Y-axis direction. The Z-axis direction is parallel to the vertical direction, the X-axis direction and the Y-axis direction are orthogonal to each other, and are parallel to the horizontal direction.

[0021] As shown in FIGS. 1 and 2, the secondary battery 1 includes a battery case 10 composed of a case body 11 and a sealing plate 12, metal battery terminals PS and NS, an electrode body 20, a bag body 40, and the like. The secondary battery 1 is a sealed secondary battery in which the electrode body 20, a part of the battery terminals PS and NS, the bag body 40, etc. are accommodated inside the case body 11, the opening of the case body 11 is sealed with the sealing plate 12, and then the electrolyte E is injected into the case body 11.

[0022] 〔Configuration of Battery Case 10〕 As shown in FIGS. 1 and 2, the battery case 10 of this embodiment is composed of a case body 11 with an open top and a sealing plate 12 that seals the opening of the case body 11. In the battery case 10 of this embodiment, both the case body 11 and the sealing plate 12 are made of aluminum, but it is not limited thereto. Various metals and alloys can be used as the materials for the case body 11 and the sealing plate 12. In this embodiment, the case body 11 corresponds to the "housing", and the sealing plate 12 corresponds to the "lid body".

[0023] In this embodiment, the case body 11 has a substantially rectangular parallelepiped shape. The case body 11 has a pair of side walls 11a provided opposite to each other along the longitudinal direction (X-axis direction), a pair of end side walls 11b that connect the ends of the side walls 11a in the longitudinal direction (X-axis direction), and a bottom portion 11c that closes the bottom.

[0024] The sealing plate 12 has a shape corresponding to the shape of the opening of the case body 11 and is configured to be able to seal the opening of the case body 11. The sealing plate 12 is composed of a flat plate member that is substantially rectangular when viewed in the Z-axis direction. On the sealing plate 12, a positive electrode battery terminal PS is disposed on one end side in the longitudinal direction (one end side in the X-axis direction), and a negative electrode battery terminal NS is disposed on the other end side in the longitudinal direction (the other end side in the X-axis direction). The sealing plate 12 is joined to the case body 11 by laser welding or the like so as to close the opening of the case body 11.

[0025] 〔Configuration of the electrode body 20〕 The electrode body 20 is formed by laminating a positive electrode material and a negative electrode material with a separator interposed therebetween, and is housed in the case body 11. The electrode body 20 of the present embodiment is configured as a wound body obtained by winding a long strip-shaped positive electrode material and a negative electrode material in a laminated state with a strip-shaped separator interposed therebetween and compressing it into a flat shape. As shown in FIGS. 1 and 2, the electrode body 20 is substantially rectangular in a thickness direction view (Y-axis direction view), and a positive electrode terminal bonding portion 21 where the positive electrode material is collected is formed on one end side in the longitudinal direction (X-axis direction) in the thickness direction view, and a negative electrode terminal bonding portion 22 where the negative electrode material is collected is formed on the other end side. Note that the structure of the electrode body 20 is not particularly limited, and various structures used in general sealed secondary batteries can be adopted. Also, aluminum is used for the positive electrode material and copper is used for the negative electrode material.

[0026] The electrode body 20 is housed inside the case body 11 in a posture where the thickness direction and the longitudinal direction are parallel to the horizontal direction while being housed inside the bag body 40 described later. Although details will be described later, the electrode body 20 is insulated from the case body 11 by the bag body 40.

[0027] 〔Configuration of positive electrode side and negative electrode side〕 In the present embodiment, the secondary battery 1 includes a positive electrode external terminal 25 and a negative electrode external terminal 26 as external terminals, and a positive electrode current collecting terminal 27 and a negative electrode current collecting terminal 28 as current collecting terminals. The positive electrode battery terminal PS is composed of the positive electrode external terminal 25 and the positive electrode current collecting terminal 27, and the negative electrode battery terminal NS is composed of the negative electrode external terminal 26 and the negative electrode current collecting terminal 28. In the present embodiment, the positive electrode external terminal 25 and the positive electrode current collecting terminal 27 are made of aluminum, and the negative electrode external terminal 26 and the negative electrode current collecting terminal 28 are made of copper. However, the materials of the external terminals 25, 26 and the current collecting terminals 27, 28 are not particularly limited, and various metals and alloys with good conductivity can be used.

[0028] Also, in the present embodiment, each of the secondary batteries 1 includes a positive electrode insulating member 29, a negative electrode insulating member 30, a positive electrode gasket 31, and a negative electrode gasket 32, all made of insulating materials. In the present embodiment, a PFA resin is used as the insulating material, but it is not limited thereto.

[0029] Although detailed description is omitted, in the secondary battery 1 of the present embodiment, the positive electrode external terminal 25 and the negative electrode external terminal 26 are insulated from the sealing plate 12 by the positive electrode gasket 31 and the negative electrode gasket 32, respectively, and the positive electrode current collecting terminal 27 and the negative electrode current collecting terminal 28 are insulated from the sealing plate 12 by the positive electrode insulating member 29 and the negative electrode insulating member 30, respectively. Also, each of the current collecting terminals 27, 28 has connection portions 27a, 28a, and the respective connection portions 27a, 28a are joined to the terminal joining portions 21, 22.

[0030] 〔Configuration of the bag body〕 Next, the bag body 40 will be described in detail. FIG. 3 is a developed view of the insulating film F constituting the bag body 40. FIG. 4 is a perspective view showing the bag body 40. FIG. 5 is a side view showing a part of the bag body 40 viewed from the X-axis direction. FIG. 6 is a front view showing a part of the bag body 40 viewed from the Y-axis direction. FIGS. 7 and 8 are schematic diagrams for explaining the process of inserting the insulating film into the case body. FIGS. 7(a) and 8(a) are views when viewed from above, and FIGS. 7(b) and 8(b) are views when viewed from one side in the Y-axis direction.

[0031] As shown in FIGS. 1, 2, and 4, the bag body 40 has an opening at the upper part and is disposed inside the case body 11 such that the opening faces the opening side of the case body 11. Also, the bag body 40 houses the electrode body 20 therein and insulates between the case body 11 and the electrode body 20.

[0032] In the present embodiment, the bag body 40 is formed by folding a single insulating film F having insulating properties and flexibility. In the present embodiment, the insulating film F is a polypropylene film having a substantially rectangular shape in plan view, but it is not limited thereto.

[0033] As shown in FIG. 3, the insulating film F has two rectangular side portions 41 and 42, rectangular end side portions 43 and 44 disposed on both longitudinal sides of the other side portion 42, a rectangular bottom portion 45 disposed between the two side portions 41 and 42, guide portions 46 and 47 disposed on the opposite sides of the boundaries between the end side portions 43 and 44 and the side portion 42, and rectangular cover portions 48 and 49 disposed on both longitudinal sides of the bottom portion 45.

[0034] Folding lines (valley folding lines) L1 and L2 are formed at the boundaries between the two side portions 41 and 42 and the end side portions 43 and 44. Further, folding lines (valley folding lines) L3 and L4 are formed at the boundaries between the side portions 41 and 42 and the bottom portion 45. Furthermore, folding lines (valley folding lines) L5 and L6 are formed at the boundaries between the end side portions 43 and 44 and the guide portions 46 and 47. Also, folding lines (valley folding lines) L7 and L8 are formed at the boundaries between the bottom portion 45 and the cover portions 48 and 49. In addition, notch portions C1 and C2 that will become the gap S of the bag body 40 described later are formed between the end side portions 43 and 44 and the cover portions 48 and 49. Note that the width W1 of the notch portions C1 and C2 is shorter than the length W2 of the sides of the cover portions 48 and 49 that face the end side portions 43 and 44. Also, each of the folding lines L1 to L7 corresponds to the boundary line between adjacent portions.

[0035] In the present embodiment, bevel portions 46a and 47a are formed on a part of the edges of the guide portions 46 and 47 that are located on the opposite sides of the boundaries with the end side portions 43 and 44. Specifically, the bevel portions 46a and 47a start from the intersection point P1 of the boundary lines (folding lines L5 and L6) with the end side portions 43 and 44 and the sides facing the cover portions 48 and 49, and end at an arbitrary point on the edge of the guide portions 46 and 47 that is located on the opposite side of the boundary with the side portion 42, and are the portions extending linearly from the start point P1 to the end point P2. In other words, the bevel portions 46a and 47a are inclined so as to separate from the end side portions 43 and 44 as they separate from the sides facing the cover portions 48 and 49.

[0036] The bag body 40 is formed by folding the insulating film F along each folding line L1 to L8. Specifically, the end side surface portions 43 and 44 are folded along the folding lines L1 and L2 so as to straddle both longitudinal ends of the two side surface portions 41 and 42, and the guide portions 46 and 47 are folded along the folding lines L5 and L6 so as to face the surface 41a of one of the side surface portions 41. Thereafter, the cover portions 48 and 49 are folded so as to face the end side surface portions 43 and 44. Thereby, the bag body 40 including the two side surface portions 41 and 42, the two end side surface portions 43 and 44, the bottom surface portion 45, the two guide portions 46 and 47, and the two cover portions 48 and 49 is formed.

[0037] Next, the configuration of the bag body 40 will be described. As shown in FIGS. 1, 2, and 4, the bag body 40 of the present embodiment includes a pair of side surface portions 41 and 42 provided to face each other along the longitudinal direction (X-axis direction), a pair of end side surface portions 43 and 44 provided to face each other along the short-side direction (Y-axis direction), a bottom surface portion 45 located on the side opposite to the side where the opening is located (lower side in the Z-axis direction), guide portions 46 and 47 provided to face portions on both sides in the X-axis direction of the surface 41a of one of the side surface portions 41, and cover portions 48 and 49 provided to face lower portions of the surfaces 43a and 44a of the end side surface portions 43 and 44. Inside the bag body 40, the side surfaces 23a and 23b, which are the long-side surfaces of the electrode body 20, face the side surface portions 41 and 42, and the electrode body 20 is accommodated so that both end surfaces 24a and 24b in the longitudinal direction (X-axis direction) of the electrode body 20 face the end side surface portions 43 and 44. That is, the end side surface portions 43 and 44 of the bag body 40 face the end surfaces 24a and 24b parallel to the lamination direction in the electrode body 20.

[0038] In this embodiment, each end side surface portion 43, 44 is a portion where the portions located on both sides of the insulating film F constituting one side surface portion 41 in the X-axis direction are bent. That is, each end side surface portion 43, 44 is a portion where the end of the insulating film F constituting one side surface portion 41 is bent. Further, each guide portion 46, 47 is a portion where the portion of the insulating film F constituting each end side surface portion 43, 44 located on the opposite side of the boundary (bending lines L1, L2) with the side surface portion 41 is bent toward the surface 42a of the other side surface portion 42. That is, each guide portion 46, 47 is a portion where the end of the insulating film F constituting each end side surface portion 43, 44 is bent toward the surface 42a of the other side surface portion 42. Also, each cover portion 48, 49 is a portion where the portions located on both sides of the insulating film F constituting the bottom surface portion 45 in the X-axis direction are bent toward the surfaces 43a, 44a of each end side surface portion 43, 44. That is, each cover portion 48, 49 is a portion where the end of the insulating film F constituting the bottom surface portion 45 is bent toward the surfaces 43a, 44a of each end side surface portion 43, 44.

[0039] In this embodiment, inclined hypotenuse portions 46a, 47a connecting the starting point P1 and the ending point P2 are formed in the guide portions 46, 47. As shown in FIGS. 4 to 6, the starting point P1 of the hypotenuse portion 47a formed in the guide portion 47 is located on the edge on one side in the Y-axis direction of the cover portion 49 in the view in the X-axis direction in the state of being housed inside the case body 11. That is, the starting point P1 is located at a position overlapping the cover portion 49 in the view in the direction orthogonal to the surface 44a of the end side surface portion 44. Also, as shown in FIGS. 4 and 6, the ending point P2 of the hypotenuse portion 47a is located on the edge of the insulating film F located on the opposite side of the boundary (bending line L6) with the end side surface portion 44 in the guide portion 47 and above the starting point P1. More specifically, the ending point P2 is located above the horizontal plane including the starting point P1 on the edge of the insulating film F in the direction orthogonal to the boundary line between the guide portion 47 and the end side surface portion 44. Although an inclined hypotenuse portion 46a is also formed in the guide portion 46, since it has the same characteristics as the hypotenuse portion 47a, detailed description thereof is omitted.

[0040] Also, in the bag body 40 of the present embodiment, a gap S is formed between each end side surface portion 43, 44 and the bottom surface portion 45 in a view in the X-axis direction. That is, the gap S is formed at a position facing the end surfaces 24a, 24b of the electrode body 20 in a state where the electrode body 20 is accommodated in the bag body 40. Specifically, as shown in FIGS. 4 to 6, the gap S opens between the lower ends of the end side surface portions 43, 44 and one end in the X-axis direction of the bottom surface portion 45, and is a substantially rectangular gap in a view in the X-axis direction. Further, the gap S has a predetermined width W1 in the height direction (Z-axis direction).

[0041] Also, in the present embodiment, the cover portions 48, 49 have a length W2 from the boundary lines (bending lines L7, L8) with the bottom surface portion 45 to the edge in the direction orthogonal to the boundary lines. That is, the length W2 of the cover portions 48, 49 is the length from the boundary lines with the bottom surface portion 45 to the edge on the side opposite to the boundary lines. And the length W2 of the cover portions 48, 49 is longer than the width W1 of the gap S, and in the present embodiment, the width W1 of the gap S is greater than 0% and 50% or less of the length W2 of the cover portions 48, 49.

[0042] As shown in FIGS. 4 to 6, the cover portions 48, 49 of the present embodiment cover the entire gap S when viewed from the X-axis direction. Note that the width W1 of the gap S and the length W2 of the cover portions 48, 49 may be any dimensions as long as the cover portions 48, 49 can cover the gap S in a state where the bag body 40 is accommodated in the case main body 11. For example, they may be appropriately set in consideration of the distance between the end side surface portions 43, 44 and the inner wall surface of the case main body 11 in a state where the bag body 40 is accommodated in the case main body 11.

[0043] In the secondary battery 1 having the above configuration, when inserting the bag body 40 (insulating film F folded along the folding lines L1 to L8) into the case main body 11 in order to assemble the secondary battery 1, as shown in FIG. 7, before insertion, the ends of the guide portions 46 and 47 and the cover portions 48 and 49 may be located outside the edge of the opening in the case main body 11 when viewed in the Z-axis direction. When the bag body 40 is inserted into the case main body 11 in this state, as shown in FIG. 8, the hypotenuse portions 46a and 47a of the cover portions 48 and 49 and the guide portions 46 and 47 come into contact with the edge of the opening in the case main body 11. Then, the cover portions 48 and 49 are bent toward the surfaces 43a and 44a of the end side surface portions 43 and 44, and the end side surface portions 43 and 44 are folded toward the electrode body 20 in a form pressed by the cover portions 48 and 49. Further, the guide portions 46 and 47 in which the hypotenuse portions 46a and 47a are in contact with the edge of the opening of the case main body 11 are folded toward the surface 41a of the side surface portion 41 while the hypotenuse portions 46a and 47a smoothly move along the edge of the opening.

[0044] Therefore, in the present embodiment, when the bag body 40 is inserted into the case main body 11, the end side surface portions 43 and 44, the guide portions 46 and 47, and the cover portions 48 and 49 are smoothly folded without being caught by the edge of the opening of the case main body 11. Therefore, according to the secondary battery of the present embodiment, the secondary battery 1 can be smoothly assembled without performing a process of pre-forming the bag body 40 using adhesion or the like. That is, the secondary battery 1 according to the present embodiment can be manufactured by a simple assembling operation, and the workability during assembly is also good.

[0045] Further, in the secondary battery 1 according to the present embodiment, a gap S is formed at positions facing the end faces 24a and 24b of the electrode body 20, so that the electrolytic solution E can flow back and forth between the inside and outside of the bag body 40 through the gap S. Therefore, the electrolytic solution E is easily supplied to the vicinity of the end faces 24a and 24b of the electrode body 20 accommodated in the bag body 40, and the amount of the electrolytic solution that can penetrate from the end faces 24a and 24b of the electrode body 20 into the inside increases, so that the electrolytic solution E can be effectively utilized. Further, in accordance with the expansion and contraction of the electrode body 20 accompanying charge and discharge, the amount of the electrolytic solution in the bag body 40 can be easily adjusted. Further, in the secondary battery 1, since the gap S is covered by the cover portions 48 and 49, conduction between the electrode body 20 and the case body 11 through the gap S can be prevented.

[0046] 〔Alternative Embodiment〕 〔1〕In the above embodiment, the mode in which the hypotenuse portions 46a and 47a are formed in the guide portions 46 and 47 has been described, but the present invention is not limited to such a mode. The hypotenuse portion may be formed from the end side surface portion to the guide portion. FIG. 9 is a developed view of the insulating film G constituting the bag body 60 according to an alternative embodiment, and FIG. 10 is a perspective view showing the bag body 60 according to the alternative embodiment.

[0047] As shown in FIG. 9, the insulating film G has two rectangular side surface portions 61 and 62, end side surface portions 63 and 64 disposed on both longitudinal sides of the other side surface portion 62, a rectangular bottom surface portion 65 disposed between the two side surface portions 61 and 62, guide portions 66 and 67 disposed on the opposite side of the boundary between the side surface portion 62 in each end side surface portion 63 and 64, and rectangular cover portions 68 and 69 disposed on both longitudinal sides of the bottom surface portion 65. Notch portions that become the gap S after assembly are formed between each end side surface portion 63 and 64 and each cover portion 68 and 69.

[0048] In this embodiment, the hypotenuse portions 70a and 70b are formed from the respective end side surfaces 63 and 64 to the respective guide portions 66 and 67. Specifically, in this embodiment, the hypotenuse portions 70a and 70b start from an arbitrary point on the side opposite to the respective cover portions 68 and 69 on the sides of the respective end side surfaces 63 and 64 facing the cover portions 68 and 69 as the starting point P1, and end at an arbitrary point on the edge of the respective guide portions 66 and 67 located on the opposite side of the boundary with the respective end side surfaces 63 and 64 as the ending point P2, and are the portions extending from the starting point P1 to the ending point P2.

[0049] And although detailed description is omitted, by folding the insulating film G along a predetermined folding line, as shown in FIG. 10, a bag body 60 having a pair of side surfaces 61 and 62, a pair of end side surfaces 63 and 64, a bottom surface 65, two guide portions 66 and 67, and two cover portions 68 and 69, and having a gap S between the end side surfaces 63 and 64 and the bottom surface 65 is formed. In this bag body 60, the starting point P1 of the hypotenuse portions 70a and 70b overlaps with the respective cover portions 68 and 69 in the direction perpendicular to the surface of the respective end side surfaces 63 and 64 in a state where the bag body 60 is accommodated in the case body.

[0050] Even in such a manner, when inserting the bag body 60 (the insulating film G folded along the folding line) into the case body 11, the end side surfaces 63 and 64 are folded toward the side of the electrode body 20 in a form of being pushed by the cover portions 68 and 69 that are folded and contacted by the case body 11, and the hypotenuse portions 70a and 70b contact the edge of the opening of the case body 11, and while the guide portions 66 and 67 are folded toward the surface of the side surface 61, the bag body 60 is accommodated in the case body 11. Therefore, it is possible to smoothly assemble the secondary battery without performing a step of forming the bag body using adhesion or the like. Thus, even in such a manner, a secondary battery that can be manufactured by a simple assembling operation and has good workability during assembly can be realized.

[0051] [2] In the above-described embodiment, the aspect in which a gap S is formed between each end side surface portion 43, 44 and the bottom surface portion 45 when viewed in a direction orthogonal to the surfaces 43a, 44a of each end side surface portion 43, 44 has been described. However, the present invention is not limited to such an aspect. An aspect in which no gap S is formed between each end side surface portion 43, 44 and the bottom surface portion 45 may also be employed. Even in such an aspect, smooth assembly of the secondary battery is possible without requiring prior assembly using adhesion or the like.

[0052] [3] In the above-described embodiment, the aspect in which the length W1 of the gap S is greater than 0% and 50% or less of the length W2 of each cover portion 48, 49 has been described. However, the present invention is not limited to such an aspect. There is no particular limitation as long as the width W1 of the gap S is shorter than the length W2 of the cover portions 48, 49. The width W1 of the gap S and the length W2 of the cover portions 48, 49 may be the width and length by which the gap S is covered by the cover portions 48, 49 when viewed from a direction orthogonal to the surface 43a of each end side surface portion 43, 44 in a state where the bag body 40 is housed inside the case body 11.

[0053] [4] In the above-described embodiment, the aspect in which each of the two end side surface portions 43, 44 is formed by bending each end of the insulating film F that constitutes the other side surface portion 42 has been described. However, the present invention is not limited to such an aspect. For example, one of the two end side surface portions 43, 44, i.e., the end side surface portion 43, may be formed by bending the end of the insulating film F that constitutes one side surface portion 41, and the other end side surface portion 44 may be formed by bending the end of the insulating film F that constitutes the other side surface portion 42. There is no particular limitation as long as at least one of the end side surface portions is formed by bending the end of the insulating film that constitutes the side surface portion.

[0054] Note that the configurations disclosed in the above-described embodiments (including other alternative embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in other embodiments as long as no contradiction occurs. Also, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope not departing from the object of the present invention.

Explanation of Reference Numerals

[0055] 1: Secondary battery 11: Case body (housing) 12: Sealing plate (cover) 20: Electrode body 24a, 24b: End faces 40: Bag body 41, 42: Side faces 43, 44: End side faces 43a, 44a: Surfaces 45: Bottom face 46, 47: Guide parts 46a, 47a: Hypotenuse parts 48, 49: Cover parts PS: Positive electrode battery terminal NS: Negative electrode battery terminal S: Gap F: Insulating film G: Insulating film W1: Width (width of the gap) W2: Length (length of the cover part) P1: Starting point P2: End point

Claims

1. A housing having an opening, A lid for sealing the opening of the housing, An electrode body attached to the lid via a battery terminal and housed in the housing, A bag body disposed inside the housing for insulating between the housing and the electrode body, and comprising: The bag body is formed by folding an insulating film, Two opposing side portions, At least one of which is two end side portions formed by bending the end of the insulating film constituting one of the two side portions, A bottom surface portion closing the bottom, A guide portion formed by bending the end of the insulating film constituting one of the end side portions toward the surface of the other side portion, And a cover portion formed by bending the edge of the insulating film constituting the bottom surface portion toward the surface of one of the end side portions, A secondary battery, wherein in a view in a direction orthogonal to the surface of one of the end side portions in a state where the bag body is housed in the housing, a starting point is located at a position overlapping the cover portion, and an end point is located on the edge of the insulating film located on the opposite side of the boundary with one of the end side portions in the guide portion and above the starting point, and an inclined hypotenuse connecting the starting point and the end point is formed.

2. In a view in a direction orthogonal to the surface of one of the end side portions, a gap is formed between one of the end side portions and the bottom surface portion, The cover portion covers the gap in a view in a direction orthogonal to the surface of one of the end side portions, The length from the boundary line between the cover portion and the bottom surface portion to the edge on the side opposite to the boundary line is longer than the width of the gap in the height direction of the secondary battery. The secondary battery according to claim 1.

3. The electrode body is formed by laminating a positive electrode material and a negative electrode material via a separator, The two end side portions of the bag body face an end face parallel to the lamination direction of the electrode body. The secondary battery according to claim 2.

4. The width of the gap is greater than 0% and less than or equal to 50% of the length of the cover portion. The secondary battery according to claim 2 or 3.

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