Secondary batteries

Abstract

To prevent welding distortion of a housing.SOLUTION: In a secondary battery 10, a body part 210 of a housing 200 has a bottom face part 211, a first side face part 212A, a second side face part 212B, a first top plate part 213A, a second top plate part 213B, and a welded part 217. The first top plate part 213A extends from an end of the first side face part 212A on an opposite side of the bottom face part 211 toward the second side face part 212B. The second top plate part 213B extends from an end of the second side face part 212B on the opposite side of the bottom face part 211 toward the first side face part 212A. The welded part 217 connects a leading edge of the first top plate part 213A and a leading edge of the second top plate part 213B to each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to secondary batteries. [Background technology]

[0002] Patent Document 1 (JP 2013-143332 A) discloses a battery in which a battery case and a lid are joined by forming a weld at the butt joint between them. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-143332 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to improve the energy density of secondary batteries, there is a demand for larger secondary battery casings. In the battery disclosed in Patent Document 1, an open end is formed on the upper side of the battery case (casing). A lid is connected to this open end by welding. If the casing of such a battery is further enlarged in the width direction perpendicular to the height direction, the weld length of the open end will become even longer. This can further increase welding distortion of the casing. This can ultimately reduce the dimensional accuracy of the casing.

[0005] The present disclosure has been made in view of the above-mentioned problems, and has an object to provide a secondary battery in which welding distortion of the casing is suppressed and the dimensional accuracy of the casing is improved. [Means for solving the problem]

[0006] A secondary battery according to the present disclosure includes an electrode assembly and a housing. The housing accommodates the electrode assembly. The housing is configured so that the width dimension is longer than the height dimension and the thickness dimension. The thickness direction is perpendicular to the height direction. The width direction is perpendicular to both the height direction and the thickness direction. The housing includes a main body, a first sealing body, and a second sealing body. The main body has a cylindrical shape. The main body has a first opening and a second opening at both ends in the width direction. The first sealing body closes the first opening. The second sealing body closes the second opening. The main body has a bottom surface, a first side surface, a second side surface, a first top surface, a second top surface, and a welded portion. The bottom surface is located on one side in the height direction. The first side surface stands up along the height direction from one end in the thickness direction of the bottom surface. The second side surface portion stands upright in the height direction from the other end in the thickness direction of the bottom surface portion. The first top surface portion extends from an end of the first side surface portion opposite the bottom surface portion side toward the second side surface portion. The second top surface portion extends from an end of the second side surface portion opposite the bottom surface portion side toward the first side surface portion. The welded portion connects the leading edge of the first top surface portion and the leading edge of the second top surface portion to each other.

[0007] According to the above configuration, since the leading edges are welded to each other, the welding length on the opposite side of the bottom surface can be shortened compared to when the housing has an opening on the opposite side of the bottom surface, which in turn can suppress welding distortion of the housing and ultimately improve the dimensional accuracy of the housing. [Effects of the Invention]

[0008] According to the present disclosure, welding distortion of the housing can be suppressed, and the dimensional accuracy of the housing can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a secondary battery according to a first embodiment. [Figure 2] FIG. 1 is an exploded perspective view of a secondary battery according to a first embodiment. [Figure 3]FIG. 2 is a cross-sectional view taken along line III-III shown in FIG. [Figure 4] FIG. 1 is a plan view of a secondary battery according to a first embodiment. [Figure 5] 5A and 5B are diagrams schematically showing the process of molding the main body in the first embodiment. [Figure 6] FIG. 2 is a cross-sectional view taken along line VI-VI shown in FIG. [Figure 7] FIG. 10 is a plan view of a secondary battery according to a second embodiment. [Figure 8] 8A and 8B are diagrams schematically showing the process of molding the main body in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Each embodiment of the present disclosure will be described with reference to the drawings, in which the same or corresponding components are designated by the same reference numerals.

[0011] (Embodiment 1) Fig. 1 is a perspective view of a secondary battery according to embodiment 1. Fig. 2 is an exploded perspective view of the secondary battery according to embodiment 1. Fig. 3 is a cross-sectional view taken along line III-III shown in Fig. 1. Fig. 4 is a plan view of the secondary battery according to embodiment 1.

[0012] As shown in FIGS. 1 to 4, the secondary battery 10 according to the first embodiment includes an electrode assembly 100, a housing 200, a positive electrode member 620 as a positive electrode terminal, and a negative electrode member 520 as a negative electrode terminal.

[0013] The housing 200 has a substantially rectangular parallelepiped shape. The housing 200 is configured so that the dimension in the width direction W is longer than the dimension in the height direction H and the dimension in the thickness direction T. The thickness direction T is a direction perpendicular to the height direction H. The housing 200 is also configured so that the dimension in the height direction H is longer than the dimension in the thickness direction T. The thickness direction T is a direction parallel to the direction in which the positive electrode 110 and the negative electrode 120 (see FIG. 6 ), which will be described later, are arranged side by side. The width direction W is a direction perpendicular to both the height direction H and the thickness direction T.

[0014] The housing 200 accommodates the electrode assembly 100 and an electrolyte (not shown) inside. The housing 200 includes a main body 210, a first sealing member 510, and a second sealing member 610.

[0015] The main body 210 has a cylindrical shape with a first opening 218 and a second opening 219 provided on both sides in the width direction W. The first opening 218 is provided on one side in the width direction W, and the second opening 219 is provided on the other side in the width direction W. The main body 210 is made of a metal such as aluminum.

[0016] The main body 210 has a bottom surface 211, a first side surface 212A, a second side surface 212B, a first top surface 213A, a second top surface 213B, and a welded portion 217.

[0017] The bottom surface portion 211 is located on one side in the height direction H. The bottom surface portion 211 has a rectangular outer shape when viewed in the height direction H.

[0018] The first side surface portion 212A stands up along the height direction H from one end of the bottom surface portion 211 in the thickness direction T. The second side surface portion 212B stands up along the height direction H from the other end of the bottom surface portion 211 in the thickness direction T. The first side surface portion 212A and the second side surface portion 212B have a rectangular outer shape when viewed in the thickness direction T. The first side surface portion 212A and the second side surface portion 212B may be inclined with respect to the height direction H. The first side surface portion 212A and the second side surface portion 212B may extend so as to approach each other as they move away from the bottom surface portion 211.

[0019] The first top surface portion 213A extends from the end of the first side surface portion 212A opposite to the bottom surface portion 211 side toward the second side surface portion 212B.

[0020] The first top surface portion 213A has a first base portion 214A, a first inner side surface portion 215A, and a first tip portion 216A. The first base portion 214A is continuous with the first side surface portion 212A and extends along the thickness direction T. The first inner side surface portion 215A extends from the first base portion 214A toward the bottom surface portion 211. The first inner side surface portion 215A is inclined obliquely with respect to the height direction H. The first tip portion 216A extends from the first inner side surface portion 215A along the thickness direction T, and comprises the tip edge of the first top surface portion 213A.

[0021] The second top surface portion 213B extends from the end of the second side surface portion 212B opposite to the bottom surface portion 211 side toward the first side surface portion 212A.

[0022] The second top surface portion 213B has a second base portion 214B, a second inner side surface portion 215B, and a second tip portion 216B. The second base portion 214B is continuous with the second side surface portion 212B and extends along the thickness direction T. The second inner side surface portion 215B extends from the second base portion 214B toward the bottom surface portion 211. The second inner side surface portion 215B is inclined obliquely with respect to the height direction H. The second tip portion 216B extends from the second inner side surface portion 215B along the thickness direction T, and has a tip edge of the second top surface portion 213B.

[0023] Welded portion 217 connects the leading edge of first top surface portion 213A and the leading edge of second top surface portion 213B to each other. That is, welded portion 217 is formed by connecting the leading edge of first top surface portion 213A and the leading edge of second top surface portion 213B by welding. The welding method is not particularly limited, but may be, for example, laser welding. Welded portion 217 includes weld beads formed by the above welding. The weld beads protrude from first top surface portion 213A and second top surface portion 213B to the side opposite to the bottom surface portion 211.

[0024] The welded portion 217 extends in only one direction along the width direction W. The welded portion 217 is located on the first tip portion 216A and the second tip portion 216B, and is located closer to the bottom surface portion 211 in the height direction H than the first base portion 214A and the second base portion 214B.

[0025] In this embodiment, the main body 210 has a plurality of welded portions 217 as the above-mentioned welded portions 217. The plurality of welded portions 217 are spaced apart from one another. The plurality of welded portions 217 are lined up in the width direction W.

[0026] The main body 210 further has a liquid inlet 224 and a sealing member 225. The sealing member 225 seals the liquid inlet 224. The liquid inlet 224 is a through-hole for injecting an electrolyte solution into the casing 200 during the manufacturing process of the secondary battery 10. The liquid inlet 224 is sealed by the sealing member 225. The sealing member 225 is a member that seals the liquid inlet 224 after the electrolyte solution is injected into the casing 200.

[0027] In this embodiment, the liquid inlet 224 is provided between the first tip 216A and the second tip 216B. The sealing member 225 is located closer to the bottom surface 211 than the first base 214A and the second base 214B in the height direction H. The hole shape of the liquid inlet 224 is not particularly limited, but may be, for example, a circular shape.

[0028] In this embodiment, the main body 210 has a plurality of inlets 224 as the above-described inlet 224. By injecting the electrolyte solution through each of the plurality of inlets 224, the electrolyte solution can be efficiently permeated throughout the separator 130 (see FIG. 6 ), which will be described later. From the viewpoint of improving the permeation of the electrolyte solution, it is preferable that at least one inlet 224 is disposed so that the distance from the negative electrode member 520 and the distance from the positive electrode member 620 are substantially equal. It is also preferable that at least one inlet 224 is disposed closer to the negative electrode member 520 than the positive electrode member 620. It is also preferable that at least one inlet 224 is disposed closer to the positive electrode member 620 than the negative electrode member 520. It is preferable that the main body 210 has three or more inlets 224. It is preferable that the number of inlets 224 is as small as possible from the viewpoint of reducing the costs involved in forming the inlets 224 and preparing the sealing member 225.

[0029] Here, a method for molding the main body portion 210 will be described. Fig. 5A is a plan view showing a plate-shaped member prepared for molding the main body portion in embodiment 1. Fig. 5B is a plan view showing the state of the plate-shaped member immediately after bending in embodiment 1. In the plate-shaped member 210P shown in Figs. 5A and 5B, the same numbers as those indicating the respective components of the main body portion 210 are assigned to the portions corresponding to the respective components of the main body portion 210.

[0030] 5A, the plate-shaped member 210P has a flat plate-like outer shape. Specifically, the plate-shaped member 210P is prepared by punching a thin aluminum plate. At this time, a plurality of notches corresponding to the liquid pouring holes 224 are formed in the plate-shaped member 210P.

[0031] 5A and 5B, the bottom surface portion 211, the first side surface portion 212A, the second side surface portion 212B, the first top surface portion 213A, and the second top surface portion 213B are formed by bending the plate-shaped member 210P at multiple locations. Therefore, the main body portion 210 can be easily formed into various sizes. Note that each of the above-mentioned surface portions may be formed by roll-forming the plate-shaped member 210P.

[0032] Then, the leading edges of the plate-like members 210P formed in this way are welded together, avoiding the notch corresponding to the liquid pouring port 224, to form a weld 217 (see FIG. 4), and the main body 210 is formed.

[0033] As shown in FIGS. 1 to 3 , the first sealing body 510 closes the first opening 218. The first sealing body 510 has a flat plate shape. The first sealing body 510 is made of a metal such as aluminum. A negative electrode member 520 is provided in the first sealing body 510. The first sealing body 510 is fixed to the first opening 218 by, for example, laser welding. A pressure release valve 515 is provided in the first sealing body 510. The pressure release valve 515 is configured to rupture when the internal pressure of the casing 200 reaches or exceeds a predetermined pressure. When the pressure release valve 515 ruptures, gas within the casing 200 is discharged to the outside of the casing 200, thereby reducing the internal pressure within the casing 200. The negative electrode member 520 is provided in the first sealing body 510.

[0034] The negative electrode member 520 is provided on the outer surface of the first sealing member 510. The negative electrode member 520 functions as a negative electrode terminal. The negative electrode member 520 includes a negative electrode terminal plate 521 and an insulating plate 522.

[0035] Negative electrode terminal plate 521 is formed in a substantially rectangular parallelepiped shape. Negative electrode terminal plate 521 is held by insulating plate 522. Insulating plate 522 is fixed to the outer surface of first sealing body 510. Insulating plate 522 insulates first sealing body 510 from negative electrode terminal plate 521. Negative electrode terminal plate 521 and insulating plate 522 each have a through hole through which a negative electrode connecting pin 533 (described later) is inserted.

[0036] The second sealing body 610 closes the second opening 219. The second sealing body 610 has a flat plate shape. The second sealing body 610 is made of a metal such as aluminum. A positive electrode member 620 is provided in the second sealing body 610. The second sealing body 610 is fixed to the second opening 219 by, for example, laser welding or the like. A pressure release valve 615 is provided in the second sealing body 610. The pressure release valve 615 is provided so as to rupture when the internal pressure of the casing 200 reaches or exceeds a predetermined pressure. When the pressure release valve 615 ruptures, gas within the casing 200 is discharged to the outside of the casing 200, thereby reducing the internal pressure within the casing 200. The positive electrode member 620 is provided in the second sealing body 610.

[0037] The positive electrode member 620 is provided on the outer surface of the second sealing member 610. The positive electrode member 620 functions as a positive electrode terminal. The positive electrode member 620 has a positive electrode terminal plate 621 and a terminal block 622.

[0038] The positive electrode terminal plate 621 is formed in a rectangular parallelepiped shape and is made of a metal such as aluminum.

[0039] Terminal block 622 is formed in a rectangular parallelepiped shape. Terminal block 622 is made of a metal (such as iron) different from the metal making up positive electrode terminal plate 621. Terminal block 622 is fixed to the outer surface of second sealing body 610 by welding or the like. Positive electrode terminal plate 621 is fixed to terminal block 622 by welding or the like. Main body 210 and second sealing body 610 are electrically connected to positive electrode terminal plate 621 via terminal block 622, and are charged with the same polarity as positive electrode terminal plate 621. A through hole is formed in each of positive electrode terminal plate 621 and terminal block 622, through which a positive electrode connecting pin 633 (described later) is inserted.

[0040] An insulating plate may be disposed between the positive electrode component 620 and the second sealing member 610, thereby electrically insulating the positive electrode component 620 from the second sealing member 610. In this case, an insulating plate may be disposed instead of the terminal block 622, or an insulating plate may be disposed between the terminal block 622 and the second sealing member 610.

[0041] The secondary battery 10 further includes a negative electrode connecting member 530, a negative electrode side first insulating member 540, a negative electrode side second insulating member 550, and an insulator 560 on the negative electrode member 520 side.

[0042] The negative electrode connecting member 530 connects the negative electrode current collector 110N and the negative electrode terminal plate 521. The negative electrode current collector 110N is a portion of the electrode body 100 formed by bundling together a plurality of negative electrode tabs 122n (described later). The negative electrode connecting member 530 includes a negative electrode first current collector 531, a negative electrode second current collector 532, and a negative electrode connecting pin 533.

[0043] The negative electrode first current collector 531 is made of a thin plate-like conductive member and is connected to the negative electrode current collector 110N by laser welding, ultrasonic welding, or the like.

[0044] The negative electrode second current collector 532 is made of a thin plate-like conductive member. The negative electrode second current collector 532 is connected to the negative electrode first current collector 531 by laser welding, ultrasonic welding, or the like. The negative electrode second current collector 532 has a holding portion 532a that holds the negative electrode connecting pin 533. The holding portion 532a has a flat plate shape. A through hole is provided in the holding portion 532a, and the base end of the negative electrode connecting pin 533 is inserted into the through hole.

[0045] The negative electrode connecting pin 533 connects the negative electrode second current collector 532 and the negative electrode terminal plate 521. The negative electrode connecting pin 533 includes a cylindrical portion. The tip side of the cylindrical portion penetrates the first sealing body 510, the insulating plate 522, and the negative electrode terminal plate 521, and is crimped to the negative electrode terminal plate 521.

[0046] The negative electrode side first insulating member 540 has a generally plate-like shape. The negative electrode side first insulating member 540 is disposed so as to be in contact with the inner surface of the first sealing member 510. The negative electrode side first insulating member 540 is provided with a through-hole 542 through which the negative electrode connecting pin 533 is inserted.

[0047] The negative electrode side second insulating member 550 is disposed between the negative electrode side first insulating member 540 and the electrode body 100. The negative electrode side second insulating member 550 is provided with a slit 552 through which the negative electrode current collecting portion 110N is inserted.

[0048] The negative electrode first insulating member 540 and the negative electrode second insulating member 550 are assembled to form an accommodation space therebetween, in which the negative electrode current collector 110N, the negative electrode first current collector 531, and the negative electrode second current collector 532 inserted through the slits 552 are disposed.

[0049] Insulator 560 has a shape that covers the cylindrical portion of negative electrode connecting pin 533. Insulator 560 provides insulation between negative electrode connecting pin 533 and casing 200 (more specifically, first sealing member 510).

[0050] The negative electrode member 520, first sealing body 510, negative electrode connecting member 530, negative electrode side first insulating member 540, negative electrode side second insulating member 550, and insulator 560 are assembled together to form the first lid assembly 50.

[0051] The first lid assembly 50 is fixed to the main body 210 by attaching the first sealing body 510 to the first opening 218 with the negative electrode current collecting portion 110N and the negative electrode connecting member 530 fixed by welding or the like.

[0052] The secondary battery 10 further includes a positive electrode connecting member 630, a positive electrode side first insulating member 640, a positive electrode side second insulating member 650, and an insulator 660 on the positive electrode member 620 side.

[0053] The positive electrode connecting member 630 connects the positive electrode current collector 110P and the positive electrode terminal plate 621. The positive electrode current collector 110P is a portion of the electrode body 100 formed by bundling together a plurality of positive electrode tabs 112p (described later). The positive electrode connecting member 630 includes a positive electrode-side first current collector 631, a positive electrode-side second current collector 632, and a positive electrode connecting pin 633.

[0054] The positive electrode first current collector 631 is made of a thin plate-like conductive material and is connected to the positive electrode current collector 110P by laser welding, ultrasonic welding, or the like.

[0055] The positive electrode side second current collector 632 is made of a thin plate-like conductive material. The positive electrode side second current collector 632 is connected to the positive electrode side first current collector 631 by laser welding, ultrasonic welding, or the like. The positive electrode side second current collector 632 has a holding portion 632a that holds the positive electrode connecting pin 633. The holding portion 632a has a flat plate shape. A through hole is provided in the holding portion 632a, and the base end of the positive electrode connecting pin 633 is inserted into the through hole.

[0056] The positive electrode connecting pin 633 connects the positive electrode second current collector 632 and the positive electrode terminal plate 621. The positive electrode connecting pin 633 includes a cylindrical portion. The tip side of the cylindrical portion penetrates the second sealing body 610, the terminal block 622, and the positive electrode terminal plate 621, and is crimped to the positive electrode terminal plate 621.

[0057] The positive electrode side first insulating member 640 has a generally plate-like shape. The positive electrode side first insulating member 640 is disposed so as to be in contact with the inner surface of the second sealing member 610. The positive electrode side first insulating member 640 is provided with a through-hole 642 through which the positive electrode connecting pin 633 is inserted.

[0058] The positive electrode side second insulating member 650 is disposed between the positive electrode side first insulating member 640 and the electrode body 100. The positive electrode side second insulating member 650 is provided with a slit 652 through which the positive electrode current collecting part 110P is inserted.

[0059] The positive electrode-side first insulating member 540 and the positive electrode-side second insulating member 550 are assembled so as to form an accommodation space therebetween, in which the positive electrode current collector 110P, the positive electrode-side first current collector 631, and the positive electrode-side second current collector 632 inserted through the slits 552 are disposed.

[0060] Insulator 660 has a shape that covers the cylindrical portion of positive electrode connecting pin 633. Insulator 660 provides insulation between positive electrode connecting pin 633 and casing 200 (more specifically, second sealing member 610).

[0061] The positive electrode member 620, second sealing body 610, positive electrode connecting member 630, positive electrode side first insulating member 640, positive electrode side second insulating member 650, and insulator 660 are assembled together to form the second lid assembly 60.

[0062] The second lid assembly 60 is fixed to the main body 210 by attaching the second sealing body 610 to the second opening 219 with the positive current collecting portion 110P and the positive connecting member 630 fixed by welding or the like.

[0063] Fig. 6 is a cross-sectional view taken along line VI-VI shown in Fig. 1. For convenience, Fig. 6 omits the housing 200 of the secondary battery 10 and shows only the electrode assembly 100. Details of the electrode assembly 100 will be described with reference to Fig. 6.

[0064] 6, the electrode assembly 100 includes a plurality of positive electrodes 110, a plurality of negative electrodes 120, and a separator 130. The plurality of positive electrodes 110 and the plurality of negative electrodes 120 are arranged alternately in the thickness direction T while being insulated by the separator 130.

[0065] Each negative electrode 120 is formed in a rectangular shape with the lengthwise direction W as the longitudinal direction and the widthwise direction H as the transverse direction. Each negative electrode 120 has a negative electrode current collector foil 122 and negative electrode active material layers 124 provided on both sides of the negative electrode current collector foil 122. The negative electrode current collector foil 122 has a negative electrode tab 122n (see FIG. 3) on which the negative electrode active material layer 124 is not provided. The negative electrode tab 122n protrudes toward one side in the widthwise direction W.

[0066] Each positive electrode 110 is formed in a rectangular shape with the width direction W as the long side and the height direction H as the short side. Each positive electrode 110 has a positive electrode current collector foil 112 and positive electrode active material layers 114 provided on both sides of the positive electrode current collector foil 112 in the thickness direction T. The positive electrode current collector foil 112 has a positive electrode tab 112p (see FIG. 3) on which the positive electrode active material layer 114 is not provided. The positive electrode tab 112p protrudes toward the other side in the width direction W.

[0067] The separator 130 provides insulation between the positive electrode 110 and the negative electrode 120. The separator 130 is made of an insulating material and has minute voids that allow ions to pass through. The separator 130 is formed in a zigzag shape.

[0068] The separator 130 has a rectangular shape before being folded in a zigzag shape. The separator 130 is disposed between the positive electrode 110 and the negative electrode 120 while being folded in a zigzag shape. The separator 130 has a plurality of intervening portions 132a, a plurality of first folded portions 132b, a plurality of second folded portions 132c, and an outermost covering portion 132d.

[0069] Each intervening portion 132a is interposed between the positive electrode 110 and the negative electrode 120 that are adjacent to each other in the thickness direction T. In other words, each intervening portion 132a has the function of insulating the positive electrode 110 and the negative electrode 120 from each other. Each intervening portion 132a is formed of a rectangular region.

[0070] Each first folded portion 132b connects one side end in the height direction H of adjacent intervening portions 132a in the thickness direction T so that the positive electrode 110 is located between them. The first folded portion 132b is disposed on one side (above) of the positive electrode 110 in the height direction H.

[0071] Each second folded portion 132c connects the other end portions in the height direction H of the intervening portions 132a that are adjacent to each other in the thickness direction T so that the negative electrode 120 is located therebetween. The second folded portion 132c is disposed on the other side (below) of the negative electrode 120 in the height direction H.

[0072] The outermost covering portion 132d collectively covers each of the first folded portions 132b and each of the second folded portions 132c. More specifically, the outermost covering portion 132d collectively covers all of the positive electrodes 110, all of the negative electrodes 120, all of the intervening portions 132a, all of the first folded portions 132b, and all of the second folded portions 132c while being wound around a central axis parallel to the width direction W. The end 132e of the outermost covering portion 132d is set in a range that does not overlap with the positive electrode active material layer 114 and the negative electrode active material layer 124 in the thickness direction T. In this embodiment, the end 132e of the outermost covering portion 132d is provided below each of the positive electrodes 110 and each of the negative electrodes 120. Note that the peripheral surfaces and bottom surfaces of the multiple positive electrodes 110, the multiple negative electrodes 120, and the separator 130 may be covered with an insulating film (not shown).

[0073] As described above, in the secondary battery 10 according to the first embodiment of the present disclosure, the main body 210 has a cylindrical shape. The main body 210 includes a bottom surface 211, a first side surface 212A, a second side surface 212B, a first top surface 213A, a second top surface 213B, and a welded portion 217. The bottom surface 211 is located on one side in the height direction H. The first side surface 212A stands upright along the height direction H from one end of the bottom surface 211 in the thickness direction T. The second side surface 212B stands upright along the height direction H from the other end of the bottom surface 211 in the thickness direction T. The first top surface 213A extends from an end of the first side surface 212A opposite the bottom surface 211 side toward the second side surface 212B. Second top surface portion 213B extends toward first side surface portion 212A from the end of second side surface portion 212B opposite bottom surface portion 211. Welded portion 217 connects the leading edge of first top surface portion 213A and the leading edge of second top surface portion 213B to each other.

[0074] According to the above configuration, the welding length on the opposite side of bottom surface portion 211 can be shortened compared to when housing 200 has an opening on the opposite side of bottom surface portion 211. This in turn can suppress welding distortion of housing 200. In particular, when housing 200 has a long dimension in width direction W, the welding length can be shortened more effectively.

[0075] In this embodiment, the welded portion 217 extends in only one direction along the width direction W. With this configuration, the weld length can be made shorter, and welding distortion of the housing 200 can be further suppressed.

[0076] In this embodiment, the first top surface portion 213A has a first base portion 214A, a first inner side surface portion 215A, and a first tip portion 216A. The first base portion 214A is continuous with the first side surface portion 212A and extends along the thickness direction T. The first inner side surface portion 215A extends from the first base portion 214A toward the bottom surface portion 211. The first tip portion 216A extends from the first inner side surface portion 215A along the thickness direction T and comprises the tip edge of the first top surface portion 213A. The second top surface portion 213B has a second base portion 214B, a second inner side surface portion 215B, and a second tip portion 216B. The second base portion 214B is continuous with the second side surface portion 212B and extends along the thickness direction T. The second inner surface portion 215B extends from the second base portion 214B toward the bottom surface portion 211. The second tip portion 216B extends from the second inner surface portion 215B along the thickness direction T, and has a tip edge of the second top surface portion 213B. The welded portion 217 is located on the first tip portion 216A and the second tip portion 216B, and is located closer to the bottom surface portion 211 in the height direction H than the first base portion 214A and the second base portion 214B.

[0077] The above configuration can prevent the welded portion 217 from coming into contact with other items outside the secondary battery 10. This makes it easier to handle the secondary battery 10.

[0078] In this embodiment, the main body 210 further has a liquid inlet 224 and a sealing member 225. The liquid inlet 224 is provided between the first tip 216A and the second tip 216B. The sealing member 225 seals the liquid inlet 224. The sealing member 225 is located closer to the bottom surface 211 in the height direction H than the first base 214A and the second base 214B.

[0079] According to the above configuration, the liquid injection port 224 can be easily provided without punching out the plate-like member that constitutes the main body 210. Furthermore, it is possible to prevent the sealing member 225 from coming into contact with other items outside the secondary battery 10. This makes it easier to handle the secondary battery 10.

[0080] (Embodiment 2) Next, a secondary battery according to a second embodiment of the present disclosure will be described. In the secondary battery according to the second embodiment of the present disclosure, the configuration of the liquid filling port, the welded portion, etc. differs from that of the secondary battery 10 according to the first embodiment of the present disclosure. Therefore, the description of the same configuration as that of the secondary battery 10 according to the first embodiment of the present disclosure will not be repeated.

[0081] 7 is a plan view of a secondary battery according to Embodiment 2. As shown in FIG. 7, in a secondary battery 10x according to Embodiment 2 of the present disclosure, a liquid inlet 224x is provided in at least one of the first base 214A and the second base 214B. This allows the liquid inlet 224x to be positioned more reliably away from the welded portion 217x, making it easier to attach the sealing member 225 to the liquid inlet 224x without contacting the welded portion 217x compared to Embodiment 1. In this embodiment, a plurality of liquid inlets 224x are provided in each of the first base 214A and the second base 214B.

[0082] Fig. 8A is a plan view showing a plate-shaped member prepared for molding a main body portion in embodiment 2. Fig. 8B is a plan view showing the state of the plate-shaped member immediately after bending in embodiment 2. In plate-shaped member 210Px shown in Figs. 8A and 8B, the same numbers as those indicating the respective components of main body portion 210 in embodiment 2 are assigned to the portions corresponding to the respective components of main body portion 210.

[0083] As shown in FIGS. 8A and 8B, in the second embodiment of the present disclosure, a plurality of liquid pouring holes 224x are formed in advance by punching out a plate-shaped member 210Px.

[0084] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims rather than the above description of the embodiments, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0085] 10, 10x secondary battery, 50 first lid assembly, 60 second lid assembly, 100 electrode body, 110 positive electrode, 110N negative electrode current collector, 110P positive electrode current collector, 112 positive electrode current collector foil, 112p positive electrode tab, 114 positive electrode active material layer, 120 negative electrode, 122 negative electrode current collector foil, 122n negative electrode tab, 124 negative electrode active material layer, 130 separator, 132a interposition portion, 132b first folded portion, 132c second folded portion, 132d outermost coating portion, 132e termination, 200 housing, 210 main body portion, 210P, 210Px plate-shaped member, 211 bottom portion, 212A first side portion, 212B second side portion, 213A First top surface portion, 213B Second top surface portion, 214A First base portion, 214B Second base portion, 215A First inner surface portion, 215B Second inner surface portion, 216A First tip portion, 216B Second tip portion, 217, 217x Welding portion, 218 First opening portion, 219 Second opening portion, 224, 224x Inlet port, 225 Sealing member, 510 First sealing body, 515, 615 Pressure release valve, 520 Negative electrode member, 521 Negative electrode terminal plate, 522 Insulating plate, 530 Negative electrode connecting member, 531, 631 First current collector, 532, 632 Second current collector, 532a, 632a Holding portion, 533 Negative electrode connecting pin, 540, 640 First insulating member, 542, 642 Through hole, 550, 650 second insulating member, 552, 652 slit, 560, 660 insulator, 610 second sealing body, 620 positive electrode member, 621 positive electrode terminal plate, 622 terminal block, 630 positive electrode connecting member, 633 positive electrode connecting pin.

Claims

1. An electrode body; a housing that houses the electrode body, the housing is configured such that a dimension in a width direction perpendicular to both the height direction and the thickness direction is longer than a dimension in a height direction and a dimension in a thickness direction perpendicular to the height direction, the housing includes a main body having a cylindrical shape and a first opening and a second opening at both ends in the width direction, a first sealing body that closes the first opening, and a second sealing body that closes the second opening; The main body portion is a bottom surface portion located on one side in the height direction; a first side surface portion standing upright along the height direction from one end of the bottom surface portion in the thickness direction; a second side surface portion standing upright along the height direction from the other end of the bottom surface portion in the thickness direction; a first top surface portion extending from an end of the first side surface portion opposite to the bottom surface portion toward the second side surface portion; a second top surface portion extending from an end of the second side surface portion opposite to the bottom surface portion toward the first side surface portion; a welded portion connecting a leading edge of the first top surface portion and a leading edge of the second top surface portion to each other, the first top surface portion has a first base portion continuing from the first side surface portion and extending along the thickness direction, a first inner side surface portion extending from the first base portion toward the bottom surface portion, and a first tip portion extending from the first inner side surface portion along the thickness direction and having a tip edge of the first top surface portion, the second top surface portion has a second base portion continuing from the second side surface portion and extending along the thickness direction, a second inner side surface portion extending from the second base portion toward the bottom surface portion, and a second tip portion extending from the second inner side surface portion along the thickness direction and having a tip edge of the second top surface portion, the welded portion is located on the first tip portion and the second tip portion, and is located closer to the bottom portion than the first base portion and the second base portion in the height direction.

2. The secondary battery according to claim 1 , wherein the welded portion extends in only one direction along the width direction.

3. the main body further includes a liquid injection port provided between the first tip portion and the second tip portion, and a sealing member that seals the liquid injection port; The secondary battery according to claim 1 , wherein the sealing member is located closer to the bottom surface side than the first base portion and the second base portion in the height direction.

4. The secondary battery according to claim 1 , wherein the main body further includes a liquid inlet provided in at least one of the first base and the second base, and a sealing member that seals the liquid inlet.

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