Secondary batteries

Abstract

To prevent projection of a welded part on an end face.SOLUTION: In a secondary battery 10 based on the present disclosure, a first end face part 216A extends from one end in a width direction W of a first side face part 215A toward a second side face part 215B. A second end face part 216B extends from one end in a width direction W of a second side face part 215B toward a first side face part 215A. An end face welded part 220 connects a leading edge of the first end face part 216A and a leading edge of the second end face part 216B to each other. The leading edge of the first end face part 216A is located closer to a center of a housing 200 than the connection portion with the first side face part 215A in the width direction W. The leading edge of the second end face part 216B is located closer to the center of a housing 200 than the connection portion with the second side face part 215B in the width direction W.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Japanese Patent Laid-Open Publication No. 2013-125737 (Patent Document 1) discloses a secondary battery including a case that houses an electrode assembly. The main body of the case is formed by bending a single metal plate and welding the edges of the folded metal plate together. The metal plate has a bottom surface, a pair of side surfaces, and four half end surfaces. The edges of the opposing half end surfaces are butted together and joined by welding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-125737 Summary of the Invention [Problem to be solved by the invention]

[0004] To improve the energy density of secondary batteries, there is a demand for larger secondary battery casings. Regarding secondary batteries such as those disclosed in Patent Document 1, it has been considered to lengthen the case in the direction in which the end faces are aligned (width direction). However, if the case is lengthened in the width direction, the welds on the end faces may protrude in the width direction, making the secondary battery difficult to handle.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide a secondary battery that can prevent welds from protruding from the end faces. [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 has a main body portion having an opening and a sealing body that closes the opening. The main body portion has a bottom surface portion, a first side surface portion, a second side surface portion, a first end surface portion, a second end surface portion, and an end surface weld. The bottom surface portion is located on one side in the height direction. The first side surface portion stands up along the height direction from one end in the thickness direction of the bottom surface portion. The second side surface portion stands up along the height direction from the other end in the thickness direction of the bottom surface portion. The first end surface portion extends from one end in the width direction of the first side surface portion toward the second side surface portion. The second end surface portion extends from one end of the second side surface portion in the width direction toward the first side surface portion. The end surface weld connects the leading edge of the first end surface portion and the leading edge of the second end surface portion to each other. The leading edge of the first end surface portion is located closer to the center of the housing in the width direction than the connection portion with the first side surface portion. The leading edge of the second end surface portion is located closer to the center of the housing in the width direction than the connection portion with the second side surface portion.

[0007] According to the above configuration, the leading edges of the first end surface portion and the second end surface portion are positioned as described above, so that the end surface welded portion can be prevented from protruding in the width direction. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to prevent the welded portion from protruding from the end surface. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a secondary battery according to an embodiment; [Figure 2] 1 is an exploded perspective view of a secondary battery according to an embodiment; [Figure 3] FIG. 2 is a cross-sectional view taken along line III-III shown in FIG. [Figure 4]1 is a view of a secondary battery according to an embodiment, viewed from an end face side; [Figure 5] 5A and 5B are diagrams that schematically show a process for molding a main body portion in one embodiment. [Figure 6] FIG. 2 is a cross-sectional view taken along line VI-VI shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

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

[0011] Fig. 1 is a perspective view of a secondary battery according to one embodiment. Fig. 2 is an exploded perspective view of a secondary battery according to one embodiment. Fig. 3 is a cross-sectional view taken along line III-III shown in Fig. 1. Fig. 4 is a view of a secondary battery according to one embodiment as seen from an end face side.

[0012] As shown in Figures 1 to 4, a secondary battery 10 according to one embodiment of the present disclosure includes an electrode body 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 width direction W is a direction perpendicular to both the height direction H and 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.

[0014] The housing 200 contains the electrode assembly 100 and an electrolyte (not shown). The housing 200 has a main body 210 provided with an opening OP, and a sealing body 510 that closes the opening OP.

[0015] The opening OP of the main body 210 is provided on one 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 top surface 212, a first side surface 215A, a second side surface 215B, a first end surface 216A, a second end surface 216B, an end surface weld 220, a liquid inlet 224, and a sealing member 225.

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

[0018] The top surface 212 is located on the other side in the height direction H. The top surface 212 has a substantially rectangular outer shape when viewed in the height direction H.

[0019] In this embodiment, the top surface portion 212 has a first top surface portion 213A, a second top surface portion 213B, and a top surface weld portion 214.

[0020] The first top surface portion 213A and the second top surface portion 213B face each other in the thickness direction T. The first top surface portion 213A and the second top surface portion 213B are joined together by welding. This welding forms a top surface weld 214. The top surface weld 214 extends in one direction along the width direction W.

[0021] Top surface portion 212 may be a single plate-like member as a whole. When main body portion 210 has an opening opposite bottom surface portion 211, top surface portion 212 may be a sealing body that seals this opening.

[0022] The first side surface portion 215A 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 215B 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 215A and the second side surface portion 215B have a rectangular outer shape when viewed from the thickness direction T. The first side surface portion 215A and the second side surface portion 215B may be inclined with respect to the height direction H. The first side surface portion 215A and the second side surface portion 215B may extend so as to approach each other as they move away from the bottom surface portion 211.

[0023] The first side surface portion 215A is connected to the top surface portion 212, specifically to an edge of the first top surface portion 213A. The second side surface portion 215B is connected to the top surface portion 212, specifically to an edge of the second top surface portion 213B.

[0024] The first end surface portion 216A extends from one end of the first side surface portion 215A in the width direction W toward the second side surface portion 215B. The tip edge of the first end surface portion 216A is located closer to the center of the housing 200 in the width direction W than the connection portion with the first side surface portion 215A.

[0025] The first end surface portion 216A has a first base portion 217A, a first inner side surface portion 218A, and a first tip portion 219A. The first base portion 217A is continuous with the first side surface portion 215A and extends along the thickness direction T. The first inner side surface portion 218A extends from the first base portion 217A toward the center of the housing 200. The first inner side surface portion 218A is inclined obliquely with respect to the width direction W. The first tip portion 219A extends from the first inner side surface portion 218A along the thickness direction T, and has a tip edge of the first end surface portion 216A.

[0026] The second end surface portion 216B extends from one end of the second side surface portion 215B in the width direction W toward the first side surface portion 215A. The tip edge of the second end surface portion 216B is located closer to the center of the housing 200 in the width direction W than the connection portion with the second side surface portion 215B.

[0027] The second end surface portion 216B has a second base portion 217B, a second inner side surface portion 218B, and a second tip portion 219B. The second base portion 217B is continuous with the second side surface portion 215B and extends along the thickness direction T. The second inner side surface portion 218B extends from the second base portion 217B toward the center of the housing 200. The second inner side surface portion 218B is inclined obliquely with respect to the width direction W. The second tip portion 219B extends from the second inner side surface portion 218B along the thickness direction T, and has a tip edge of the second end surface portion 216B.

[0028] End face weld 220 connects the leading edge of first end face portion 216A and the leading edge of second end face portion 216B to each other. That is, end face weld 220 is formed by connecting the leading edge of first end face portion 216A and the leading edge of second end face portion 216B by welding. The welding method is not particularly limited, but may be, for example, laser welding. End face weld 220 includes weld beads formed by the above welding. The weld beads protrude from first end face portion 216A and second end face portion 216B toward the outside of housing 200.

[0029] End face welds 220 extend in only one direction along height direction H. End face welds 220 are located on first tip portion 219A and second tip portion 219B. End face welds 220 are located closer to the center of housing 200 in width direction W than first base portion 217A and second base portion 217B.

[0030] Furthermore, in this embodiment, the main body 210 has a plurality of end face welds 220 as the above-described end face welds 220. The plurality of end face welds 220 are spaced apart from one another. The plurality of end face welds 220 are aligned in the height direction H. Furthermore, the end face welds 220 may be provided so as to be continuous with the top face welds 214.

[0031] In this embodiment, one end edges of 216A and 216B in the height direction H are also joined by welding to the bottom surface portion 211. The other end edges of the first end surface portion 216A and the second end surface portion 216B in the height direction are also joined by welding to the top surface portion 212.

[0032] The liquid filling port 224 is a through-hole for injecting an electrolyte into the casing 200 during the manufacturing process of the secondary battery 10. The sealing member 225 seals the liquid filling port 224. The sealing member 225 is provided to seal the liquid filling port 224 after the electrolyte is injected into the casing 200.

[0033] The liquid inlet 224 is provided between the first tip 219A and the second tip 219B. The sealing member 225 is located closer to the center of the housing 200 than the first base 217A and the second base 217B in the width direction W. The hole shape of the liquid inlet 224 is not particularly limited, but may be, for example, circular. The main body 210 may have a plurality of liquid inlet 224 as the above-mentioned liquid inlet 224.

[0034] Here, a method for molding main body portion 210 will be described. Fig. 5A is a plan view showing a plate-shaped member prepared for molding main body portion in one embodiment. Fig. 5B is a plan view showing the plate-shaped member immediately after being folded in one embodiment. In plate-shaped member 210P shown in Figs. 5A and 5B, the same numbers as those indicating the respective components of main body portion 210 are assigned to the portions corresponding to the respective components of main body portion 210.

[0035] 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.

[0036] 5A and 5B, plate-shaped member 210P is bent at multiple locations to form bottom surface portion 211, first top surface portion 213A, second top surface portion 213B, first side surface portion 215A, second side surface portion 215B, first end surface portion 216A, and second end surface portion 216B. Therefore, main body portion 210 can be easily formed into various sizes. The above-described surface portions may be formed by roll-forming plate-shaped member 210P. Then, by welding the leading edges of plate-shaped member 210P thus formed together while avoiding the notch corresponding to pouring port 224, top surface weld 214, end surface weld 220, and the like are formed (see FIG. 4), and main body portion 210 is formed. An opening OP of the main body portion 210 is formed by the edges of the bottom surface portion 211, the top surface portion 212, the first side surface portion 215A, and the second side surface portion 215B.

[0037] As shown in FIGS. 1 to 3 , the sealing body 510 closes the opening OP. The sealing body 510 has a flat plate shape. The sealing body 510 is made of a metal such as aluminum. A negative electrode component 520 and a positive electrode component 620 are provided in the sealing body 510. The sealing body 510 is fixed to the opening OP by, for example, laser welding. The sealing body 510 is provided with a pressure release valve 515. 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.

[0038] The negative electrode member 520 is provided on the outer surface of the sealing body 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.

[0039] 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 sealing body 510. Insulating plate 522 insulates 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.

[0040] The positive electrode member 620 is provided on the outer surface of the sealing body 510. 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.

[0041] The positive electrode terminal plate 621 is formed in a rectangular parallelepiped shape and is made of a metal such as aluminum.

[0042] 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 sealing body 510 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 sealing body 510 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.

[0043] An insulating plate may be disposed between the positive electrode component 620 and the sealing body 510, thereby electrically insulating the positive electrode component 620 from the sealing body 510. 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 sealing body 510.

[0044] The secondary battery 10 further includes a negative electrode connecting member 530, a positive electrode connecting member 630, a first insulating member 540, a second insulating member 550, and insulators 560, 660.

[0045] The negative electrode connecting member 530 connects the negative electrode current collector 120N and the negative electrode terminal plate 521. The negative electrode current collector 120N 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-side first negative electrode current collector 531, a negative electrode-side second negative electrode current collector 532, and a negative electrode connecting pin 533.

[0046] The negative electrode-side first negative electrode current collector 531 is made of a thin plate-like conductive member and is connected to the negative electrode current collector 120N by laser welding, ultrasonic welding, or the like.

[0047] The negative electrode-side second negative electrode current collector 532 is made of a thin plate-like conductive member. The negative electrode-side second negative electrode current collector 532 is connected to the negative electrode-side first negative electrode current collector 531 by laser welding, ultrasonic welding, or the like. The negative electrode-side second negative electrode 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.

[0048] The negative electrode connecting pin 533 connects the negative electrode-side second negative electrode 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 sealing body 510, the insulating plate 522, and the negative electrode terminal plate 521, and is crimped to the negative electrode terminal plate 521.

[0049] 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 positive electrode current collector 631, a positive electrode-side second positive electrode current collector 632, and a positive electrode connecting pin 633.

[0050] The positive electrode side first positive electrode current collector 631 is made of a thin plate-like conductive member and is connected to the positive electrode current collector 110P by laser welding, ultrasonic welding, or the like.

[0051] The positive electrode-side second positive electrode current collector 632 is made of a thin plate-shaped conductive member. The positive electrode-side second positive electrode current collector 632 is connected to the positive electrode-side first positive electrode current collector 631 by laser welding, ultrasonic welding, or the like. The positive electrode-side second positive electrode 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 it.

[0052] The positive electrode connecting pin 633 connects the positive electrode second positive electrode 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 sealing body 510, the terminal block 622, and the positive electrode terminal plate 621, and is crimped to the positive electrode terminal plate 621.

[0053] The first insulating member 540 has a generally plate-like shape. The first insulating member 540 is disposed so as to contact the inner surface of the sealing body 510. The first insulating member 540 is provided with a through-hole 542 through which the negative electrode connecting pin 533 is inserted, and a through-hole 642 through which the positive electrode connecting pin 633 is inserted.

[0054] The second insulating member 550 is disposed between the first insulating member 540 and the electrode body 100. The second insulating member 550 is provided with a slit 552 through which the negative electrode current collecting portion 120N is inserted, and a slit 652 through which the positive electrode current collecting portion 110P is inserted.

[0055] The first insulating member 540 and the second insulating member 550 are assembled to form an accommodation space therebetween. The accommodation space contains the negative electrode current collector 120N inserted through the slit 552, the negative electrode-side first negative electrode current collector 531, the negative electrode-side second negative electrode current collector 532, the positive electrode current collector 110P inserted through the slit 652, the positive electrode-side first positive electrode current collector 631, and the positive electrode-side second positive electrode current collector 632.

[0056] 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, sealing body 510).

[0057] 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, sealing body 510).

[0058] The negative electrode member 520, positive electrode member 620, sealing body 510, negative electrode connecting member 530, positive electrode connecting member 630, first insulating member 540, second insulating member 550, and insulators 560, 660 are assembled to form the lid assembly 50.

[0059] The lid assembly 50 is fixed to the main body 210 by attaching the sealing body 510 to the opening OP while the negative electrode current collecting portion 120N and the negative electrode connecting member 530 are fixed by welding or the like, and the positive electrode current collecting portion 110P and the positive electrode connecting member 630 are fixed by welding or the like.

[0060] Note that sealing body 510 may further be provided with a second liquid inlet 572 and a second sealing member 574. Similar to liquid inlet 224, second liquid inlet 572 is a through-hole for injecting an electrolyte solution into casing 200 during the manufacturing process of secondary battery 10. Second sealing member 574 seals second liquid inlet 572. Second sealing member 574 is provided to seal second liquid inlet 572 after the electrolyte solution has been injected into casing 200.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] Each positive electrode 110 is formed in a rectangular shape with the lengthwise direction W as the length and the heightwise direction H as the widthwise direction. 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 thicknesswise 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. Like the negative electrode tab 122n, the positive electrode tab 112p protrudes toward one side in the widthwise direction W.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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).

[0071] As described above, in secondary battery 10 according to an embodiment of the present disclosure, end surface weld 220 connects the leading edge of first end surface portion 216A and the leading edge of second end surface portion 216B to each other. The leading edge of first end surface portion 216A is located closer to the center of housing 200 in width direction W than the connection portion with first side surface portion 215A. The leading edge of second end surface portion 216B is located closer to the center of housing 200 in width direction W than the connection portion with second side surface portion 215B.

[0072] According to the above configuration, since the leading edges of the first end surface portion 216A and the second end surface portion 216B are positioned as described above, it is possible to prevent the end surface weld portion 220 from protruding in the width direction W, particularly when the end surface weld portion 220 includes a weld bead.

[0073] Furthermore, the end face welds 220 extend in only one direction along the height direction H. This makes it possible to shorten the weld length of the end face welds 220. As a result, welding distortion of the housing 200 can be suppressed.

[0074] Furthermore, the first end surface portion 216A has a first base portion 217A, a first inner side surface portion 218A, and a first tip portion 219A. The first base portion 217A is continuous with the first side surface portion 215A and extends along the thickness direction T. The first inner side surface portion 218A extends from the first base portion 217A toward the center of the housing 200. The first tip portion 219A extends from the first inner side surface portion 218A along the thickness direction T and has a tip edge of the first end surface portion 216A. The second end surface portion 216B has a second base portion 217B, a second inner side surface portion 218B, and a second tip portion 219B. The second base portion 217B is continuous with the second side surface portion 215B and extends along the thickness direction T. The second inner side surface portion 218B extends from the second base portion 217B toward the center of the housing 200. The second tip portion 219B extends from the second inner side surface portion 218B along the thickness direction T and has the tip edge of the second end surface portion 216B. The end surface welds 220 are located on the first tip portion 219A and the second tip portion 219B. The end surface welds 220 are located closer to the center of the housing 200 in the width direction W than the first base portion 217A and the second base portion 217B.

[0075] According to the above configuration, first base portion 217A and second base portion 217B extend along thickness direction T, which reduces the overall area of ​​the end faces of main body portion 210. Furthermore, first tip portion 219A and second tip portion 219B also extend along thickness direction T, which makes it easy to butt these together to form end face weld 220. Furthermore, because end face weld 220 is located on first tip portion 219A and second tip portion 219B, it is possible to further prevent end face weld 220 from protruding in width direction W.

[0076] 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 219A and the second tip 219B. The sealing member 225 seals the liquid inlet 224. The sealing member 225 is located closer to the center of the housing 200 in the width direction W than the first base 217A and the second base 217B.

[0077] 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 on the secondary battery 10 side. This makes it easier to handle the secondary battery 10.

[0078] 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]

[0079] 10 Secondary battery, 50 Lid assembly, 100 Electrode body, 110 Positive electrode, 110P Positive electrode current collector, 112 Positive electrode current collector foil, 112p Positive electrode tab, 114 Positive electrode active material layer, 120 Negative electrode, 120N Negative electrode current collector, 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 End, 200 Housing, 210 Main body portion, 210P Plate-shaped member, 211 Bottom surface portion, 212 Top surface portion, 213A First top surface portion, 213B Second top surface portion, 214 Top surface welding portion, 215A First side surface portion, 215B second side surface portion, 216A first end surface portion, 216B second end surface portion, 217A first base portion, 217B second base portion, 218A first inner side surface portion, 218B second inner side surface portion, 219A first tip portion, 219B second tip portion, 220 end surface weld portion, 224 liquid inlet, 225 sealing member, 510 sealing body, 515 pressure release valve, 520 negative electrode member, 521 negative electrode terminal plate, 522 insulating plate, 530 negative electrode connecting member, 531 first negative electrode current collector, 532 second negative electrode current collector, 532a, 632a holding portion, 533 negative electrode connecting pin, 540 first insulating member, 542, 642 through hole, 550 second insulating member, 552, 652 Slit, 560, 660 insulator, 572 second liquid filling port, 574 second sealing member, 620 positive electrode member, 621 positive electrode terminal plate, 622 terminal block, 630 positive electrode connecting member, 631 first positive electrode current collector, 632 second positive electrode current collector, 633 positive electrode connecting pin, OP opening.

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 has a main body portion having an opening and a sealing body that closes the 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 end surface portion extending from one end of the first side surface portion in the width direction toward the second side surface portion; a second end surface portion extending from one end of the second side surface portion in the width direction toward the first side surface portion; an end face weld portion connecting a leading edge of the first end face portion and a leading edge of the second end face portion to each other, a tip edge of the first end surface portion is located closer to a center of the housing than a connection portion between the first end surface portion and the first side surface portion in the width direction; a tip edge of the second end surface portion is located closer to the center of the housing than a connection portion between the second end surface portion and the second side surface portion in the width direction, the first end 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 center of the housing, and a first tip portion extending from the first inner side surface portion along the thickness direction and having the tip edge of the first end surface portion, the second end 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 center of the housing, and a second tip portion extending from the second inner side surface portion along the thickness direction and having the tip edge of the second end surface portion, the end face welds are located on the first tip portion and the second tip portion, and are located closer to the center of the housing than the first base portion and the second base portion in the width direction, the bottom surface portion, the first side surface portion, the second side surface portion, the first end surface portion, and the second end surface portion are formed by bending a flat plate-like member at multiple locations, the first base portion, the first inner surface portion, and the first tip portion are formed by further bending the plate-like member at a plurality of locations in the first end surface portion, The second base portion, the second inner surface portion, and the second tip portion are formed by further bending the plate-shaped member at multiple locations on the second end surface portion.

2. The secondary battery according to claim 1 , wherein the end face welds extend in only one direction along the height 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; 3. The secondary battery according to claim 1, wherein the sealing member is located closer to the center of the housing than the first base portion and the second base portion in the width direction.

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