Battery, method for manufacturing the case body of a battery case, and method for manufacturing a battery

Abstract

To provide a battery in which the battery case body and lid can be easily joined together. [Solution] The battery (100) comprises a battery case (10) and at least one electrode body (14). The battery case (10) includes a rectangular tubular case body (11) and a lid (12). The lid (12) is positioned at both axial ends of the case body (11) such that at least a portion of the lid (12) is located inside the case body (11). Each lid (12) is welded to the case body (11). The electrode body (14) is housed inside the battery case (10). The case body (11) has protrusions (13) formed thereon. The protrusions (13) project outwards from the inner circumference of the case body (11) and axially support each of the lids (12) from inside the case body (11).

Description

Technical Field

[0001] The present disclosure relates to a battery. The present disclosure also relates to a method for manufacturing a case body of a battery case and a method for manufacturing a battery.

Background Art

[0002] In recent years, the spread of electric vehicles including battery electric vehicles (BEVs) and hybrid electric vehicles (HEVs) has been promoted. In electric vehicles, for example, non-aqueous electrolyte secondary batteries are used. In electric vehicles, generally, a plurality of batteries connected to each other are mounted in order to ensure high output and high capacity.

[0003] [[ID=1--6]] <000--014> In order to meet the need to extend the cruising range in electric vehicles and the like, an increase in the energy density of the battery is required. For in-vehicle batteries, for example, rectangular batteries are adopted. When the battery is rectangular, the smaller the radius of curvature of the corner portion between the side walls of the battery case, the more closely the batteries can be arranged. As a result, the area of the battery case per unit area in the battery mounting space is reduced, and the loss of the battery mounting space is reduced, so that an increase in the energy density can be expected.

[0005] Patent Document 2 discloses a rectangular battery. In Patent Document 2, the battery case also includes a bottomed rectangular cylindrical case body and a lid. The lid seals an opening that the case body has at one end in the axial direction and is joined to the case body by welding. Support protrusions for supporting the lid are provided on the inner surface of the corner portion between the side walls of the case body. The support protrusions extend to the bottom of the case body.

[0006] Patent Document 3 also discloses a rectangular battery. In Patent Document 3, the battery case includes a bottomed rectangular cylindrical case body and a lid. The lid seals an opening that the case body has at one end in the axial direction and is joined to the case body by welding. In Patent Document 3, a projection for supporting the lid is formed in the corner portion between the side walls of the case body, near the opening.

[0007] The rectangular batteries described in each patent document have an upper terminal structure. That is, in the batteries described in each patent document, a lid is placed at one end (upper end) in the axial direction of a bottomed rectangular cylindrical case body, and positive and negative terminals are fixed to the upper surface of this lid. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2014-157803 [Patent Document 2] International Publication No. 2014 / 002600 [Patent Document 3] Japanese Patent Application Publication No. 11-219688 [Overview of the project] [Problems that the invention aims to solve]

[0009] In battery cases, aluminum alloy sheets are widely used for the case body and lid. However, in recent years, the use of steel sheets for battery cases has also begun to be considered. When changing the material of a battery case from aluminum alloy sheets to steel sheets, it is desirable to reduce the thickness of the battery case to maintain a similar weight. Since the density of steel is about three times that of aluminum, it is preferable that the thickness of a steel battery case be about one-third of the thickness of an aluminum alloy battery case. However, with the thinning of the battery case, joining the case body and lid may become difficult depending on the joining method.

[0010] The object of this disclosure is to provide a battery in which the case body and lid of the battery case can be easily joined together. [Means for solving the problem]

[0011] The battery according to this disclosure comprises a battery case and at least one electrode body. The battery case includes a rectangular tubular case body and a lid. The case body includes a pair of opposing first side walls, a pair of opposing second side walls, and corner portions connecting the first and second side walls. The lids are positioned at both axial ends of the case body such that at least a portion of the lid is located inside the case body. Each lid is welded to the case body. The electrode body is housed inside the battery case. The case body has protrusions formed thereon. The protrusions project inward from the case body and axially support each of the lids from inside the case body. [Effects of the Invention]

[0012] According to the battery disclosed herein, the battery case body and the lid can be easily joined together. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is an exploded perspective view showing the schematic configuration of a battery according to this embodiment. [Figure 2]FIG. 2 is a partial perspective view of the case body included in the battery shown in FIG. 1. [Figure 3] FIG. 3 is another partial perspective view of the case body included in the battery shown in FIG. 1. [Figure 4] FIG. 4 is a view of the battery shown in FIG. 1 seen along the axial direction of the case body. [Figure 5] FIG. 5 is a longitudinal sectional view of the battery shown in FIG. 1. [Figure 6A] FIG. 6A is a schematic diagram for explaining a method of manufacturing the case body of the battery case according to an embodiment. [Figure 6B] FIG. 6B is a schematic diagram for explaining a method of manufacturing the case body of the battery case according to an embodiment. [Figure 6C] FIG. 6C is a schematic diagram for explaining a method of manufacturing the case body of the battery case according to an embodiment. [Figure 6D] FIG. 6D is a schematic diagram for explaining a method of manufacturing the case body of the battery case according to an embodiment. [Figure 7A] FIG. 7A is a schematic diagram for explaining a method of manufacturing the battery according to an embodiment. [Figure 7B] FIG. 7B is a schematic diagram for explaining a method of manufacturing the battery according to an embodiment. [Figure 7C] FIG. 7C is a schematic diagram for explaining a method of manufacturing the battery according to an embodiment. [Figure 7D] FIG. 7D is a schematic diagram for explaining a method of manufacturing the battery according to an embodiment. [Figure 8] FIG. 8 is a longitudinal sectional view of the battery according to a modification of the embodiment. [Figure 9] FIG. 9 is a partial perspective view of the case body included in the battery according to another modification of the embodiment. [Figure 10] FIG. 10 is a view of the battery according to yet another modification of the embodiment seen along the axial direction of the case body. [Figure 11] FIG. 11 is a view of the battery according to yet another modification of the embodiment seen along the axial direction of the case body. [Modes for carrying out the invention]

[0014] The battery according to this embodiment comprises a battery case and at least one electrode body. The battery case includes a rectangular tubular case body and a lid. The case body includes a pair of opposing first side walls, a pair of opposing second side walls, and corner portions connecting the first and second side walls. The lids are positioned at both axial ends of the case body such that at least a portion of the lid is located inside the case body. Each lid is welded to the case body. The electrode body is housed inside the battery case. The case body has protrusions formed thereon. The protrusions project inward from the inner circumference of the case body and support each of the lids axially from inside the case body (first configuration).

[0015] In the battery according to the first configuration, lids are positioned at both axial ends of a rectangular tubular case body. Each lid is supported axially from the inside of the case body by a projection. That is, each lid is positioned axially relative to the case body by the projection inside the case body so as not to fall into the case body. Therefore, each lid can be easily joined to the case body by welding. In the battery according to the first configuration, for example, there is no need to process the open end face of the case body or the end face of the lid for positioning the lids, and the case body and each lid can be easily joined even if the plate thickness of the case body or lid is small.

[0016] In the battery according to the first configuration, it is preferable that the protruding parts are arranged at each of the corners (second configuration).

[0017] In the battery according to the first or second configuration, the electrode body may be a wound-type electrode body. The wound-type electrode body has a shape that includes a curved portion when viewed along the axial direction. The protruding portion may be arranged in the gap created between the case body and the curved portion (third configuration).

[0018] The wound electrode body has a shape that includes a curved portion when viewed along the axial direction of the case body. Therefore, when the wound electrode body is placed inside a rectangular tubular case body, a gap is created between the electrode body and the case body at the position of the curved portion of the electrode body. In the third configuration, a protrusion is placed in this gap. Therefore, the electrode body is less likely to interfere with the protrusion when inserting it into the case body or after the electrode body has been housed in the battery case.

[0019] In a battery relating to any of the first to third configurations, the case body may have a plate thickness of 0.1 mm or more and 1.0 mm or less (fourth configuration).

[0020] In a battery relating to any of the first to fourth configurations, the cover may have a plate thickness of 0.1 mm or more and 2.5 mm or less (fifth configuration).

[0021] In a battery relating to any of the first to fifth configurations, the case body and the lid may each be made of steel plate (sixth configuration).

[0022] In the sixth configuration of the battery, the battery case body and lid are made of steel plate. In this case, the rigidity of the battery case can be improved compared to, for example, the case body and lid being made of aluminum alloy plate. Alternatively, the battery case can be made thinner while maintaining the same rigidity as when the case body and lid are made of aluminum alloy plate.

[0023] In the battery according to the sixth configuration, the steel plate may be a stainless steel plate or a surface-treated steel plate (seventh configuration).

[0024] In the battery according to the seventh configuration, the battery case body and lid are made of stainless steel plate or surface-treated steel plate. Therefore, corrosion resistance of the battery case can be ensured. For example, corrosion of the battery case caused by the contents such as electrolyte can be suppressed.

[0025] The method for manufacturing the case body of the battery case according to the embodiment comprises the steps of: preparing a metal plate; forming a rectangular tubular intermediate molded product from the metal plate, which includes a pair of first side walls facing each other, a pair of second side walls facing each other, and a corner portion connecting the first side walls and the second side walls, and having open end faces on both sides in the axial direction; and forming a protruding portion in at least the vicinity of each of the open end faces of the intermediate molded product, which is spaced axially away from the open end face and protrudes toward the inner circumference of the intermediate molded product (8th configuration).

[0026] A method for manufacturing a battery according to an embodiment includes the steps of preparing a rectangular tubular case body including a pair of first side walls facing each other, a pair of second side walls facing each other, and a corner portion connecting the first and second side walls, two lids, and at least one electrode body, and arranging the lids at both axial ends of the case body such that at least a portion of each lid is located inside the case body, and welding each lid to the case body in which the electrode body is located. The case body has protrusions that project outwards from the inner circumference of the case body. In the joining step, each lid is supported axially from inside the case body by its protrusion while the lids are welded to the case body (9th configuration).

[0027] In the battery manufacturing method relating to the ninth configuration, the lid may be joined to the case body by laser welding during the joining process (tenth configuration).

[0028] Embodiments of this disclosure will be described below with reference to the drawings. In these drawings, the same or equivalent components are denoted by the same reference numerals, and the same description will not be repeated.

[0029] [battery] Figure 1 is an exploded perspective view showing the schematic configuration of the battery 100 according to this embodiment. Although not particularly limited, the battery 100 is, for example, a lithium-ion secondary battery. The battery 100 is a battery having a lateral terminal structure. A battery with a lateral terminal structure is a battery in which positive and negative terminals (not shown) are located on the side of the battery when in use. In contrast, a structure in which positive and negative terminals are located on the top surface of the battery when in use is called an upper terminal structure.

[0030] Referring to Figure 1, the battery 100 is a rectangular battery. The battery 100 includes a battery case 10. The battery case 10 includes a case body 11 and two lids 12.

[0031] The case body 11 has a substantially rectangular tubular shape. The case body 11 includes a pair of side walls 111a, 111b, a pair of side walls 112a, 112b, and corner portions 113a, 113b, 113c, 113d. The case body 11 has openings 114 at both ends in its axial direction. Hereinafter, the axial direction of the case body 11 or a corresponding direction may simply be referred to as the axial direction.

[0032] The side walls 111a and 111b each have a substantially flat shape. The side walls 111a and 111b are provided so as to face each other in the case body 11. The case body 11 may have a rectangular shape when viewed along its axial direction. In this embodiment, the side walls 111a and 111b face each other in the short-width direction of the case body 11.

[0033] The side walls 112a and 112b each have a substantially flat shape. The side walls 112a and 112b are provided so as to face each other in the case body 11. In this embodiment, the side walls 112a and 112b face each other in the longitudinal width direction of the case body 11.

[0034] Corner sections 113a, 113b, 113c, and 113d connect side walls 111a, 111b and side walls 112a, 112b. Corner section 113a is continuous with one end of side wall 111a when viewed along the axial direction, and connects side wall 111a and side wall 112a. Corner section 113b is continuous with the other end of side wall 111a when viewed along the axial direction, and connects side wall 111a and side wall 112b. Corner section 113c is continuous with one end of side wall 111b when viewed along the axial direction, and connects side wall 111b and side wall 112a. Corner section 113d is continuous with the other end of side wall 111b when viewed along the axial direction, and connects side wall 111b and side wall 112b.

[0035] Corner sections 113a, 113b, 113c, and 113d have essentially the same configuration. Therefore, unless there is a particular need to distinguish between them, corner sections 113a, 113b, 113c, and 113d are collectively referred to as corner section 113. Similarly, unless there is a particular need to distinguish between the side walls 111a, 111b and side walls 112a, 112b are collectively referred to as side wall 111 and side wall 112, respectively.

[0036] The case body 11 is formed from a metal plate. The case body 11 may be made of a steel plate. Preferably, the steel plate is a stainless steel plate. The steel plate may be a surface-treated steel plate. Surface-treated steel plates include plated steel plates. Preferably, the surface-treated steel plate is a nickel-plated steel plate. However, the case body 11 may be made of a metal plate other than a steel plate. The case body 11 may be made of a metal plate made of aluminum, titanium, copper, or an alloy thereof.

[0037] The case body 11 can be formed, for example, by bending a metal sheet multiple times and then welding the ends of the metal sheets together. Alternatively, the case body 11 may be formed by roll forming of the metal sheet. In this case, as shown in Figure 1, the case body 11 includes a welded portion 115. The welded portion 115 extends in the axial direction of the case body 11. In this embodiment, the welded portion 115 is provided on a relatively narrow side wall 112. However, the welded portion 115 may be provided on a relatively wide side wall 111.

[0038] The case body 11 may have a plate thickness of 0.1 mm or more and 1.0 mm or less. The plate thickness of the case body 11 is measured at the side wall 111 or 112. More specifically, the plate thickness of the case body 11 can be measured at a position on the side wall 111 or 112 that is 10.0 mm or more away from the opening 114 in the axial direction of the case body 11 and 2.0 mm or more away from the corner portion 113 and the welded portion 115 in the circumferential direction of the case body 11.

[0039] Figures 2 and 3 are partial perspective views of the case body 11. Figures 2 and 3 show enlarged views of the opening 114 and its vicinity within the corner portion 113 of the case body 11. Figure 2 shows the inner surface of the case body 11. Figure 3 shows the case body 11 as seen from its outer surface.

[0040] Referring to Figure 2, a protrusion 13 is formed on the case body 11. The protrusion 13 may be formed integrally with the case body 11 as part of the case body 11. The protrusion 13 projects inward from the other parts of the case body 11. In this embodiment, the protrusion 13 is located on the corner portion 113 of the case body 11.

[0041] The protrusion 13 may include surfaces 131, 132, and 133. Surfaces 131 and 132 are surfaces that intersect the axial direction of the case body 11. Surface 131 is positioned on the opening 114 side relative to surface 132. Surface 131 may be substantially perpendicular to the axial direction of the case body 11. Surfaces 131 and 132 are connected on the inside of the case body 11 by surface 133.

[0042] When viewed from the inner surface of the case body 11, the protruding portion 13 has a convex shape relative to the other parts of the case body 11. On the other hand, as shown in Figure 3, when viewed from the outer surface of the case body 11, the protruding portion 13 has a concave shape relative to the other parts of the case body 11.

[0043] Returning to Figure 1, the lids 12 are positioned at both axial ends of the case body 11. Each lid 12 seals the opening 114 of the case body 11. Each lid 12 is joined to the case body 11 by welding.

[0044] At least one of the lids 12 is provided with terminals (not shown) for the battery 100. For example, one lid 12 may have a positive terminal and the other lid 12 may have a negative terminal. Alternatively, one lid 12 may have both a positive and a negative terminal. Since the battery 100 is a battery with a lateral terminal structure, the battery case 10 has an aspect ratio of 1.5 or more. The aspect ratio of the battery case 10 may be 10.0 or less. Preferably, the aspect ratio of the battery case 10 is 2.0 or more and 4.0 or less. The aspect ratio is the ratio of the vertical dimension La of the battery case 10 to the horizontal dimension Lb of the battery case 10: Lb / La. In this embodiment, the vertical dimension La of the battery case 10 is the maximum distance between the outer surfaces of the side walls 112a, 112b that are arranged vertically when the battery case 10 is in use, and is the distance in a direction perpendicular to the axial direction. The lateral dimension Lb of the battery case 10 is the axial distance from the outer surface of one cover 12 to the outer surface of the other cover 12.

[0045] In this embodiment, each lid 12 has a substantially flat shape. Each lid 12 has, for example, a substantially rectangular shape when viewed along the axial direction of the case body 11. Each lid 12 is formed from a metal plate. Each lid 12 may be formed from a steel plate. The steel plate is preferably a stainless steel plate. The steel plate may be a surface-treated steel plate. Surface-treated steel plates include plated steel plates. The surface-treated steel plate is preferably a nickel-plated steel plate. However, the lid 12 may be formed from a metal plate other than a steel plate. The lid 12 may be formed from a metal plate made of aluminum, titanium, copper, or an alloy thereof.

[0046] Each lid 12 may have a thickness of 0.1 mm or more and 2.5 mm or less. Preferably, the thickness of each lid 12 is greater than the thickness of the case body 11. However, the thickness of the lid 12 may be less than or equal to the thickness of the case body 11. The thickness of the lid 12 can be measured on the flat portion of the lid 12 at a position of 1.0 mm or more and 5.0 mm or less from the welded joint between the case body 11 and the lid 12.

[0047] Figure 4 shows the battery 100 as viewed along its axis. For the sake of clarity, the cover 12 is omitted in Figure 4.

[0048] Referring to Figure 4, the battery 100 further comprises at least one electrode body 14. The electrode body 14 is housed in the battery case 10 together with, for example, an electrolyte.

[0049] The electrode body 14 includes a positive electrode, a negative electrode, and a separator (not shown). In this embodiment, the electrode body 14 is a wound electrode body. That is, the electrode body 14 has a structure (jelly roll structure) in which the positive electrode and the negative electrode are wound together with a separator interposed between them. In this case, the electrode body 14 has a shape (outer shape) that includes a curved portion 141 when viewed along the axial direction. The electrode body 14 can have, for example, a substantially oval track shape or a rounded rectangle shape when viewed along the axial direction. The curved portion 141 is provided at both ends of the electrode body 14 in the longitudinal width direction of the case body 11.

[0050] A gap C exists between the case body 11 and the curved portion 141 of the wound electrode body 14. In this embodiment, a relatively wide gap C exists between each corner portion 113 of the case body 11 and the curved portion 141 of the electrode body 14. It is preferable that the protruding portion 13 be positioned in this gap C.

[0051] The radius of curvature of the inner surface of the corner portion 113 of the case body 11 is preferably 3.0 mm or less. More preferably, the radius of curvature of the inner surface of the corner portion 113 is 2.5 mm or less, and even more preferably, 2.0 mm or less. The radius of curvature of the inner surface of the corner portion 113 is, for example, 0.5 mm or more, preferably 0.7 mm or more, and more preferably 1.0 mm or more. The radius of curvature of the inner surface of the corner portion 113 may be measured, for example, at a position 10.0 mm axially from any opening 114 of the case body 11. Specifically, in a cross-section (a section perpendicular to the axial direction) of the case body 11 at a position 10.0 mm axially from the opening 114, the radius of the circle passing through the three points of the end of both radii on the inner surface of the corner portion 113 and their midpoint can be used as the radius of curvature of the inner surface of the corner portion 113.

[0052] Figure 5 is a longitudinal cross-sectional view of the battery 100. The longitudinal cross-section of the battery 100 refers to the cross-section obtained when the battery 100 is cut along the axial direction of the case body 11. Figure 5 schematically shows the longitudinal cross-section of the battery 100 at the position of the corner portion 113 of the case body 11.

[0053] Referring to Figure 5, in this embodiment, protrusions 13 are formed at each corner 113 of the case body 11. The protrusions 13 are provided at each corner 113 of the case body 11 so as to correspond to each of the two lids 12.

[0054] The protrusions 13 are formed in the rectangular tubular case body 11 in the vicinity of at least each open end face 116. The vicinity of each open end face 116 refers to the portion of the case body 11 that is axially separated from each open end face 116 by 10% to 200% of the plate thickness of the lid 12. Therefore, the axial distance D from each open end face 116 to the corresponding protrusion 13 is 10% to 200% of the plate thickness of the lid 12.

[0055] The lid 12 is positioned at both axial ends of the case body 11 such that at least a portion of it is located inside the case body 11. The projections 13 of the case body 11 axially support the corresponding lid 12 from inside the case body 11. The projections 13 can contact the corresponding lid 12, for example, by the surface 131 on the open end face 116 side.

[0056] In the example shown in Figure 5, the lid 12 is positioned inside the case body 11 so that it does not protrude axially from the open end face 116 of the case body 11. However, a portion of the lid 12 may protrude axially from the open end face 116 of the case body 11.

[0057] [Manufacturing method for the case body] Next, the manufacturing method for the case body 11 of the battery case 10 used in the battery 100 will be described with reference to Figures 6A to 6D. The manufacturing method for the case body 11 according to this embodiment comprises a preparation step, a molding step, and a processing step.

[0058] (preparation process) Referring to Figure 6A, the preparation step involves preparing a metal sheet 20 as the material. The metal sheet 20 may be a blank or a coil. The metal sheet 20 is, for example, a steel sheet. Preferably, the steel sheet is a stainless steel sheet or a surface-treated steel sheet. Surface-treated steel sheets include plated steel sheets. Preferably, the surface-treated steel sheet is a nickel-plated steel sheet. The metal sheet 20 may also be a metal sheet made of aluminum, titanium, copper, or alloys thereof.

[0059] (molding process) Referring to Figures 6A and 6B, the molding process forms an intermediate molded product 11i from the metal sheet 20. As shown in Figure 6B, the intermediate molded product 11i has a substantially rectangular tubular shape. The intermediate molded product 11i includes a pair of side walls 111, a pair of side walls 112, and four corner portions 113, similar to the case body 11 (Figure 1). Also, the intermediate molded product 11i has openings 114 and open end faces 116 on both sides in its axial direction, similar to the case body 11. However, the intermediate molded product 11i does not have a protrusion 13 (Figures 2 and 3).

[0060] The method for forming the bottomless rectangular tubular intermediate molded product 11i is not particularly limited. For example, if the metal plate 20 is a blank in the shape of the unfolded case body 11 (Figure 1), the intermediate molded product 11i can be obtained by bending the metal plate 20 multiple times and then joining the end faces of the metal plate 20 together by laser welding or the like. For example, if the metal plate 20 is a coil material, the intermediate molded product 11i can also be obtained by forming the metal plate 20 into a rectangular tubular shape by roll forming, butting the end faces of the metal plate 20 together (high-frequency welding), and then cutting it to a predetermined length.

[0061] (Processing process) Figures 6C and 6D are longitudinal cross-sectional views of the intermediate molded product 11i and the case body 11 at the corner portion 113, respectively. Referring to Figures 6C and 6D, in the manufacturing process, protrusions 13 are formed in at least the vicinity of each of the opening end faces 116 of the intermediate molded product 11i. The protrusions 13 are spaced axially away from the opening end face 116 and protrude toward the inner circumference of the intermediate molded product 11i. The protrusions 13 can be formed, for example, by using a mold (not shown) to push a part of the intermediate molded product 11i from the outer surface to the inner surface. In this embodiment, protrusions 13 are formed on each of the corner portions 113 of the intermediate molded product 11i. This makes it possible to obtain the case body 11 from the intermediate molded product 11i.

[0062] The position where the protrusion 13 is formed can be determined in relation to the lid 12 which is to be attached to the case body 11. For example, the portion of the intermediate molded product 11i that is 10% to 200% of the plate thickness of the lid 12 in the axial direction from each open end face 116 can be designated as the vicinity portion of each open end face 116, and the protrusion 13 can be formed in at least this vicinity portion.

[0063] [Battery manufacturing method] Next, the manufacturing method of the battery 100 will be described with reference to Figures 7A to 7D. The manufacturing method of the battery 100 according to this embodiment comprises a preparation step and a bonding step.

[0064] (preparation process) Referring to Figure 7A, the preparation step involves preparing the case body 11, two lids 12, and at least one electrode body 14.

[0065] (Joining process) Referring to Figures 7B to 7D, in the joining process, the lids 12 are positioned at both axial ends of the case body 11 such that at least a portion of each lid 12 is located inside the case body 11, and each of the lids 12 is welded to the case body 11 in which the electrode body 14 is located.

[0066] Referring to Figure 7B, the case body 11 has a plurality of protrusions 13 formed thereon. In the joining process, each of the lids 12 is supported axially from inside the case body 11 by the protrusions 13, and the lids 12 are welded to the case body 11.

[0067] For example, one opening 114 of the case body 11 is positioned on the upper side and the other opening 114 on the lower side, and one side of the lid 12 is placed on the protrusion 13 near the upper opening 114. In this state, one side of the lid 12 is welded to the case body 11. Next, the case body 11 is inverted, and the other side of the lid 12 is placed on the protrusion 13 near the upper opening 114. In this state, the other side of the lid 12 is welded to the case body 11.

[0068] The lid 12 is joined to the case body 11, for example, by laser welding. The laser beam from the welding device 200 may be irradiated along the axial direction of the case body 11 to the boundary between the open end face 116 and the lid 12, as shown in Figure 7C. Alternatively, as shown in Figure 7D, if a part of the lid 12 protrudes axially from the open end face 116 of the case body 11, the laser beam from the welding device 200 may be irradiated from the outer circumference of the case body 11 to the boundary between the case body 11 and the lid 12. The lid 12 may also be joined to the case body 11 by, for example, electron beam welding.

[0069] After the bonding process, the case body 11 contains the electrode body 14 along with the necessary contents such as electrolyte. Furthermore, at least one side of the lid 12 is provided with a positive or negative electrode terminal (not shown) that is electrically connected to the electrode body 14. This completes the manufacturing of the battery 100 (Figure 1).

[0070] [effect] In the battery 100 according to this embodiment, a protrusion 13 is provided on the case body 11. This protrusion 13 allows the lid 12 to be supported axially from inside the case body 11. That is, when the lid 12 is positioned at each axial end of the case body 11, the axial movement of the lid 12 is restricted by the protrusion 13, and the lid 12 is positioned relative to the case body 11. Therefore, the lid 12 can be easily joined to the case body 11 by welding.

[0071] In this embodiment, a projection 13 is formed at a position axially separated from the open end face 116 of the case body 11. By simply placing each lid 12 on this projection 13, the lid 12 can be positioned relative to the case body 11. Therefore, it is not necessary to perform any processing such as steps on the open end face 116 of the case body 11 or the end face of the lid 12 for the purpose of positioning. Thus, even if the plate thickness of the case body 11 and / or the lid 12 is small, the lid 12 can be positioned relative to the case body 11, and the lid 12 can be easily welded to the case body 11.

[0072] The rectangular batteries described in each patent document have an upper terminal structure. That is, in the batteries of each patent document, a lid is placed at one end (upper end) in the axial direction of the bottomed rectangular cylindrical case body, and the positive and negative terminals are fixed to the upper surface of this lid. As a result, the vertical dimensions of the battery tend to be large. For example, in electric vehicles, many batteries are sometimes mounted under the floor. If the vertical dimensions of the battery are large, the floor of the electric vehicle will be higher, which may affect the ease of getting in and out and the ride comfort. On the other hand, the battery 100 according to this embodiment has a lateral terminal structure, so the vertical dimensions do not tend to increase. Therefore, the battery 100 according to this embodiment can reduce the impact on the ease of getting in and out and the ride comfort in electric vehicles and the like.

[0073] In the battery 100 according to this embodiment, it is preferable that the thickness of the lid 12 is greater than the thickness of the case body 11. In this case, the rigidity of the battery case 10 can be increased. More specifically, for example, in the case of a battery having an upper terminal structure, a bottomed rectangular tubular case body is generally used for the battery case. Since the bottomed rectangular tubular case body is manufactured by deep drawing, it has a generally uniform thickness throughout, including the bottom. Therefore, if the thickness of the lid is greater than the thickness of the case body, a thicker lid is placed at one end (opening side) in the axial direction of the battery case, but the other end (bottom) in the axial direction of the battery case becomes thinner.

[0074] On the other hand, the battery 100 according to this embodiment has a lateral terminal structure. Therefore, the case body 11 is a bottomless rectangular tube, and the lids 12 are joined to both ends of the case body 11 in the axial direction. If the plate thickness of the lids 12 is greater than the plate thickness of the case body 11, the thick-walled lids 12 are positioned at both ends of the battery case 10 in the axial direction. This can increase the rigidity of the battery case 10. By increasing the rigidity of the battery case 10, the load borne by each welded part may be reduced. Therefore, for example, the fatigue strength of the welded parts and the overall strength of the battery case 10 can be improved.

[0075] In the battery 100 according to this embodiment, the electrode body 14 is a wound-type electrode body. Therefore, when viewed along the axial direction of the case body 11, the electrode body 14 has a shape that includes a curved portion 141 on its surface. In this case, when the electrode body 14 is placed inside the rectangular tubular case body 11, a gap C is created between the curved portion 141 of the electrode body and the case body 11. In this embodiment, the protruding portion 13 of the case body 11 is positioned in this gap C. Therefore, when inserting the electrode body 14 into the case body 11 during the manufacturing of the battery 100, or after the electrode body 14 has been inserted into the case body 11, the electrode body 14 is less likely to interfere with the protruding portion 13.

[0076] In the battery 100 according to this embodiment, the case body 11 and the lid 12 are preferably made of steel plate. Steel plate has higher rigidity compared to aluminum alloy plate and the like. Therefore, by making the case body 11 and the lid 12 of steel plate, the rigidity of the battery case 10 can be ensured while the battery case 10 can be made thinner. As a result, when multiple batteries 100 are arranged in an electric vehicle, for example, the proportion that the battery case 10 occupies in relation to the mounting space of the batteries 100 is reduced. Therefore, the space efficiency and energy density of the battery 100 can be improved.

[0077] In the battery 100 according to this embodiment, the case body 11 and the lid 12 may be made of stainless steel plate or surface-treated steel plate. This ensures corrosion resistance of the battery case 10.

[0078] While embodiments relating to this disclosure have been described above, this disclosure is not limited to the embodiments described above, and various modifications are possible as long as they do not deviate from its spirit.

[0079] In the battery 100 according to the above embodiment, the protrusions 13 of the case body 11 are provided for each lid 12. That is, a protrusion 13 is provided near one open end face 116 of the case body 11, and a separate protrusion 13 is provided near the other open end face 116 of the case body 11. However, as shown in Figure 8, these protrusions 13 may be integrated. That is, the protrusion 13 may extend axially from the vicinity of one open end face 116 to the vicinity of the other open end face 116 of the case body 11.

[0080] In the battery 100 according to the above embodiment, the protrusions 13 of the case body 11 are located at the four corner portions 113. However, the number and arrangement of the protrusions 13 are not limited to the example of the above embodiment. For example, the protrusions 13 do not need to be located at all four corner portions 113. The protrusions 13 may be located at only two diagonally opposite corner portions 113 of the rectangular tubular case body 11. Alternatively, the protrusions 13 may be located at three corner portions 113, while the remaining corner portion 113 does not need to have a protrusion 13. The protrusions 13 may be located on the side walls 111 and / or 112 instead of or in addition to the corner portions 113. For example, as shown in Figure 9, the protrusions 13 may extend beyond the corner portions 113 to the side walls 111 and 112 in the circumferential direction of the case body 11.

[0081] In the battery 100 according to the above embodiment, the protrusions 13 of the case body 11 are arranged at the four corner portions 113. That is, a plurality of separate protrusions 13 are arranged along the circumferential direction of the case body 11. However, the protrusions 13 do not necessarily have to be divided along the circumferential direction of the case body 11. The protrusions 13 may be provided along the entire circumference of the case body 11.

[0082] In the battery 100 according to the above embodiment, a single electrode body 14 is housed in the battery case 10. However, as shown in Figure 10, a plurality of electrode bodies 14 may be housed in the battery case 10. The electrode bodies 14 are arranged in the direction of the shorter width of the case body 11, for example, when viewed along the axial direction. If these electrode bodies 14 are wound electrode bodies, a gap C is created between the curved portion 141 of each electrode body 14 and the case body 11. More specifically, a relatively large gap C is created between the curved portion 141 of adjacent electrode bodies 14 and, for example, the side wall 112 which is the shorter side of the case body 11. The protruding portion 13 may be located on the portion of the side wall 112 of the case body 11 that corresponds to the gap C.

[0083] However, the electrode body 14 does not necessarily have to be a wound electrode body. The electrode body 14 may also be a stacked electrode body.

[0084] In the battery 100 according to the above embodiment, the protrusion 13 has a convex shape relative to other parts of the case body 11 when viewed from the inner side of the case body 11, while it has a concave shape relative to other parts of the case body 11 when viewed from the outer side of the case body 11. However, the shape of the protrusion 13 when viewed from the outer side of the case body 11 is not limited to this. For example, the portion of the outer surface of the case body 11 corresponding to the protrusion 13 may be filled with some material.

[0085] In the battery 100 according to the above embodiment, the protrusion 13 has surfaces 131 and 132 that intersect in the axial direction, and a surface 133 that connects the surfaces 131 and 132, on the inner surface side of the case body 11. However, the shape of the protrusion 13 on the inner surface side of the case body 11 is not limited to this. The shape of the protrusion 13 is not particularly limited as long as it is a shape that can support the lid 12 in the axial direction from inside the case body 11.

[0086] In the above embodiment, the case body 11 is formed, for example, by bending a blank metal plate 20 multiple times and then welding the end faces of the metal plate 20 together. Alternatively, the case body 11 is formed by roll forming of a coiled metal plate 20. As a result, a welded portion 115 is formed on the side wall 111 or 112 of the case body 11. In this case, as shown in Figure 11, for example, a relief portion 121 may be formed in the part of the lid 12 corresponding to the welded portion 115. In the example of Figure 11, corresponding to the placement of the welded portion 115 on the side wall 112 of the case body 11, a relief portion 121 is provided on the short side of the rectangular plate-shaped lid 12. The relief portion 121 is formed on the periphery of the lid 12 on the part facing the welded portion 115 and has a concave shape relative to the other parts of the lid 12. This allows the weld metal to be placed in the relief portion 121 even if, for example, the weld metal of the welded portion 115 of the case body 11 bulges out toward the lid 12 side. Therefore, it becomes easier to position the lid 12 on the inner circumference side of the case body 11. [Explanation of Symbols]

[0087] 100:Battery 10: Battery case 11: Case body 11i: Intermediate molded product 111, 111a, 111b: Side wall (first side wall) 112, 112a, 112b: Side wall (second side wall) 113, 113a, 113b, 113c, 113d: Corner section 116: Open end surface 12: Lid 13: Protrusion 14: Electrode body 141: Curved part 20: Metal plate

Claims

1. It is a battery, A battery case comprising a rectangular tubular case body including a pair of first side walls facing each other, a pair of second side walls facing each other, and a corner portion connecting the first side walls and the second side walls, and a lid positioned at both axial ends of the case body such that at least a portion of it is located inside the case body, and each lid being welded to the case body, At least one electrode body housed within the battery case, Equipped with, A battery, wherein the case body has a projection that protrudes from the inner circumference of the case body and supports each of the lids from inside the case body in the axial direction.

2. The battery according to claim 1, The aforementioned protrusions are batteries, each positioned at one of the corner sections.

3. The battery according to claim 1, The electrode body is a wound-type electrode body having a shape that includes a curved portion when viewed along the axial direction, The aforementioned protruding portion is a battery positioned in the gap between the case body and the curved portion.

4. The battery according to claim 1, The aforementioned case body is a battery having a plate thickness of 0.1 mm or more and 1.0 mm or less.

5. The battery according to claim 1, The lid has a plate thickness of 0.1 mm or more and 2.5 mm or less, and is a battery.

6. The battery according to claim 1, The case body and the lid are each made of steel plate, and the battery.

7. The battery according to claim 6, The aforementioned steel plate is a stainless steel plate or a surface-treated steel plate, in a battery.

8. A method for manufacturing the case body of a battery case, The process of preparing the metal plate, A step of forming a rectangular tubular intermediate molded product from a metal sheet, which includes a pair of first side walls facing each other, a pair of second side walls facing each other, and a corner portion connecting the first side walls and the second side walls, and having open end faces on both sides in the axial direction, A step of forming a protruding portion in the vicinity of at least each of the opening end faces of the intermediate molded product, which is separated from the opening end face in the axial direction and protrudes toward the inner circumference of the intermediate molded product, A manufacturing method that includes the following features.

9. A method for manufacturing a battery, The process involves preparing a rectangular tubular case body including a pair of first side walls facing each other, a pair of second side walls facing each other, and a corner portion connecting the first and second side walls, two lids, and at least one electrode body. The steps include: positioning the lids at both axial ends of the case body such that at least a portion of each of the lids is located inside the case body, and welding each of the lids to the case body in which the electrode body is located; Equipped with, The case body has a protruding portion that extends outward from the inner circumference of the case body. A manufacturing method in which, in the joining step, each of the lids is supported in the axial direction from inside the case body by the protrusions, and the lids are welded to the case body.

10. A method for manufacturing a battery according to claim 9, A manufacturing method wherein, in the joining step, the lid is joined to the case body by laser welding.

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