Method for manufacturing a battery housing and method for manufacturing a battery

Abstract

The present application provides a battery case manufacturing method and a battery manufacturing method. The battery case manufacturing method includes: a step of forming a first thin wall portion (12A) and a second thin wall portion (12B) in a metal plate (10); a step of cutting the metal plate into a substantially rectangular shape having one pair of first end edges (21A, 21B) and one pair of second end edges (22A, 22B), wherein one of the one pair of first end edges (21A, 21B) is formed by cutting the first thin wall portion (12A), and the other of the one pair of first end edges (21A, 21B) is formed by cutting the second thin wall portion (12B); a step of bending the metal plate (10) into a cylindrical shape after the metal plate cutting step; and a step of joining one of the one pair of second end edges (22A, 22B) to the other of the one pair of second end edges (22A, 22B) after the step of bending the metal plate (10) into a cylindrical shape.

Description

Technical Field

[0001] This technology relates to a method for manufacturing a battery casing and a method for manufacturing a battery. Background Technology

[0002] For example, Japanese Patent Application Publication No. Hei 09-265966 and Japanese Patent Application Publication No. 2014-10910 show a structure in which a step is provided at the opening of the casing of a square battery.

[0003] For cylindrical battery casings with openings at both ends, a stable connection with the sealing plate is required. There is still room for improvement in existing battery casings. Summary of the Invention

[0004] The purpose of this technology is to provide a method for manufacturing a battery casing that enables a stable connection between the battery casing and the sealing plate, as well as a method for manufacturing a battery.

[0005] This technology provides the following methods for manufacturing battery casings and battery manufacturing.

[0006] [1]

[0007] A method for manufacturing a battery casing includes the following steps: forming a first thin-walled portion in a metal plate by providing a first recess on a first surface of the metal plate, and forming a second thin-walled portion in the metal plate by providing a second recess on the first surface of the metal plate; a metal plate cutting step, cutting the metal plate into a generally rectangular shape having a pair of first end edges and a pair of second end edges, wherein one of the pair of first end edges is formed by cutting the first thin-walled portion, and the other of the pair of first end edges is formed by cutting the second thin-walled portion; after the metal plate cutting step, bending the metal plate into a cylindrical shape such that one of the pair of second end edges abuts against the other of the pair of second end edges and the first surface becomes the inner surface side; and after bending the metal plate into a cylindrical shape, joining one of the pair of second end edges to the other of the pair of second end edges.

[0008] [2]

[0009] In the battery casing manufacturing method described in [1], there is also a step of forming an exhaust valve consisting of a recess on a second surface of the metal plate opposite to the first surface.

[0010] [3]

[0011] In the battery casing manufacturing method described in [2], the process of forming the above-mentioned vent valve includes the step of forming the above-mentioned recess on the second surface of the above-mentioned metal plate before bending.

[0012] [4]

[0013] In the battery casing manufacturing method described in [2], the process of forming the above-mentioned vent valve includes a step of forming the above-mentioned recess on the second surface midway through the process of bending the above-mentioned metal plate.

[0014] [5]

[0015] In any of the battery casing manufacturing methods described in [1] to [4], the process of bending the metal plate into a cylindrical shape includes bending the metal plate along a straight bending line extending parallel to the pair of second end edges. The first thin-walled portion includes a first region overlapping the bending line and a second region separated from the bending line in the direction extending from the pair of first end edges. The first region has a first length in the direction extending from the pair of second end edges, and the second region has a second length in the direction extending from the pair of second end edges. The first length is greater than the second length.

[0016] [6]

[0017] In the battery casing manufacturing method described in [5], the second thin-walled portion includes a third region that overlaps with the bending line and a fourth region that is separated from the bending line in the direction extending from the pair of first end edges. The third region has a third length in the direction extending from the pair of second end edges, and the fourth region has a fourth length in the direction extending from the pair of second end edges. The third length is greater than the fourth length.

[0018] [7]

[0019] In any of the battery casing manufacturing methods described in [1] to [6],

[0020] The aforementioned metal plate was bent into a square tube shape.

[0021] [8]

[0022] In any of the battery casing manufacturing methods described in [1] to [7], a conventional portion is formed in the metal plate between the first thin-walled portion and the second thin-walled portion, the thickness of the first thin-walled portion and the second thin-walled portion is less than the thickness of the substrate of the metal plate, and the thickness of the conventional portion is approximately the same as the thickness of the substrate of the metal plate.

[0023] [9]

[0024] In any of the battery casing manufacturing methods described in [1] to [7], a first thick wall portion adjacent to the first thin wall portion and a second thick wall portion adjacent to the second thin wall portion are formed on the metal plate, wherein the thickness of the first thin wall portion and the second thin wall portion is less than the thickness of the substrate of the metal plate, and the thickness of the first thick wall portion and the second thick wall portion is greater than the thickness of the substrate of the metal plate.

[0025]

[10]

[0026] A method for manufacturing a battery includes the following steps: forming a first thin-walled portion in a metal plate by providing a first recess on a first surface of the metal plate, and forming a second thin-walled portion in the metal plate by providing a second recess on the first surface of the metal plate; a metal plate cutting step, cutting the metal plate into a generally rectangular shape having a pair of first end edges and a pair of second end edges, wherein one of the pair of first end edges is formed by cutting the first thin-walled portion, and the other of the pair of first end edges is formed by cutting the second thin-walled portion; after the metal plate cutting step, the aforementioned... The process includes: bending the metal plate into a cylindrical shape such that one of the two second end edges abuts against the other of the two second end edges, making the first surface the inner surface side; after bending the metal plate into a cylindrical shape, joining one of the two second end edges with the other of the two second end edges to form a cylindrical battery casing; inserting an electrode into the cylindrical battery casing; sealing a first opening on one side of the cylindrical battery casing using a first sealing plate; and sealing a second opening on the other side of the cylindrical battery casing using a second sealing plate.

[0027] The above and other objects, features, aspects and advantages of the present invention will become clear from the following detailed description of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0028] Figure 1 This is a front view showing the configuration of a secondary battery according to one embodiment.

[0029] Figure 2 This indicates viewing from the direction of arrow II. Figure 1 The diagram shows the state of the secondary battery.

[0030] Figure 3 This indicates viewing from the direction of arrow III. Figure 1 The diagram shows the state of the secondary battery.

[0031] Figure 4 This indicates viewing from the direction of arrow IV. Figure 1 The diagram shows the state of the secondary battery.

[0032] Figure 5 This indicates that it is observed from the direction of arrow V. Figure 1 The diagram shows the state of the secondary battery.

[0033] Figure 6 yes Figure 1 The image shows a front cross-sectional view of a secondary battery.

[0034] Figure 7 This is a top view showing a metal plate according to one embodiment.

[0035] Figure 8 yes Figure 7 Sectional view VIII-VIII in the middle.

[0036] Figure 9 It means to Figure 7 The top view of the rectangular plate-shaped component obtained by cutting (cutting) the metal plate shown.

[0037] Figure 10 It is a cross-sectional view showing the joint between the main body of the shell and the sealing plate.

[0038] Figure 11 This is a top view showing the shape of the thin-walled portion of the plate-shaped component involved in the modified example (one of the examples).

[0039] Figure 12 This is a top view showing the shape of the thin-walled portion of the plate-shaped component involved in the modified example (second example).

[0040] Figure 13 This is a top view of the metal plate involved in the modified example (one of the examples).

[0041] Figure 14 This is a cross-sectional view of the metal plate involved in the modified example (second example).

[0042] Figure 15 This is a flowchart illustrating a method for manufacturing a secondary battery according to one embodiment. Detailed Implementation

[0043] The embodiments of this technology will be described below. Furthermore, sometimes the same or equivalent parts are labeled with the same reference numerals without repeating their description.

[0044] Furthermore, in the embodiments described below, when numbers, quantities, etc., are mentioned, the scope of this technology is not limited to those numbers, quantities, etc., unless specifically stated otherwise. Additionally, in the embodiments described below, each constituent element is not necessarily essential to this technology, unless specifically stated otherwise. Furthermore, this technology is not limited to technologies that achieve all the effects mentioned in this embodiment.

[0045] Furthermore, in this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a structure is included, other structures besides that structure may be included, or they may not be included.

[0046] Furthermore, in this specification, when using geometric terms and terms indicating positional or directional relationships, such as "parallel," "orthogonal," "45° oblique," "coaxial," and "along," these terms allow for some errors or variations. In this specification, when using terms indicating relative positional relationships such as "upper side" and "lower side," these terms are used to indicate the relative positional relationship in one state. Depending on the orientation of each mechanism (e.g., reversing the overall structure vertically), the relative positional relationship can be reversed or rotated to any angle.

[0047] Furthermore, the dimensions of the components illustrated in this specification, such as width, length, and diameter, are not limited to those shown in the illustrations and may be appropriately changed. In this specification, ordinal numbers such as "first," "second," etc., are sometimes added to each component; however, except where explicitly specified, these ordinal numbers do not limit priority, order, etc.

[0048] In this specification, "battery" is not limited to lithium-ion batteries and may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, the positive and negative electrodes may be collectively referred to as "electrodes." Additionally, the positive and negative plates may be collectively referred to as "electrode plates."

[0049] Battery cells can be installed in hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). However, the use of battery cells is not limited to vehicle applications.

[0050] In this specification, the X direction is sometimes referred to as the "width direction" of the secondary battery, electrode body, and housing body, and similarly the Z direction is referred to as the "height direction" of the secondary battery or housing body, and the Y direction is referred to as the "thickness direction" of the secondary battery or housing body.

[0051] (The overall structure of a secondary battery)

[0052] Reference Figures 1-6The overall structure of the secondary battery 1 is described below. The secondary battery 1 includes a casing 100, an electrode body 200, an electrode terminal 300, and a current collector 400. The casing 100 includes a casing body 110 (battery casing), a sealing plate 120 (first sealing plate), and a sealing plate 130 (second sealing plate).

[0053] The housing body 110 is composed of a cylindrical, preferably square, component. This results in a square secondary battery 1. The housing body 110 is made of metal. Specifically, the housing body 110 is made of aluminum, aluminum alloy, iron, or iron alloy, etc.

[0054] like Figure 1 and Figure 2 As shown, sealing plates 120 and 130 are respectively provided at both ends of the main body of the housing. The main body of the housing 110 is formed by the second end edges 22A and 22B of the plate-shaped member 20 (described later) abutting against each other (in... Figure 2 The junctions 115 (as illustrated in the example) can be joined together to form a square tube shape. The corners of the "square tube shape" may also have an R-shape. The secondary battery in this technology is not limited to a square secondary battery.

[0055] In this embodiment, the housing body 110 is formed to be longer in the width direction (X direction) than in the thickness direction (Y direction) and height direction (Z direction) of the secondary battery 1. The width of the housing body 110 in the X direction is preferably 300 mm or more. This allows for the construction of a relatively large (high-capacity) secondary battery 1. The height of the housing body 110 in the Z direction is preferably 200 mm or less, more preferably 150 mm or less, and even more preferably 100 mm or less. This allows for the construction of a relatively low-height (low-height) secondary battery 1, thereby improving, for example, vehicle mounting capability.

[0056] The housing body 110 includes a pair of first side faces 111 and a pair of second side faces 112. The pair of first side faces 111 form part of the side faces of the housing 100. The pair of second side faces 112 form the bottom and top surfaces of the housing 100. The pair of first side faces 111 and the pair of second side faces 112 are arranged to be substantially orthogonal (intersecting) to each other. The pair of first side faces 111 and the pair of second side faces 112 are connected at their respective ends. Preferably, the area of ​​the pair of first side faces 111 is larger than the area of ​​the pair of second side faces 112.

[0057] like Figure 5As shown, an exhaust valve 150 is provided on one of the two second side portions 112A. The exhaust valve 150 extends along the width direction (X direction) of the secondary battery 1. The exhaust valve 150 extends from the center of the housing body 110 in the X direction to a point that does not reach either end. The shape and arrangement of the exhaust valve 150 can be appropriately changed.

[0058] Compared to the thickness of the plate-shaped components of the housing body 110, excluding the exhaust valve 150, the plate-shaped components in the exhaust valve 150 are thin-walled. As a result, when the pressure inside the housing 100 exceeds a predetermined value, the exhaust valve 150 breaks preferentially compared to other parts of the housing body 110, thereby venting the gas inside the housing 100 to the outside.

[0059] like Figure 2 As shown, a joint portion 115 is formed on the other side surface portion 112B of the pair of second side surface portions 112. The joint portion 115 extends along the width direction (X direction) of the secondary battery 1.

[0060] like Figure 3 , Figure 4 As shown, an opening 113 (first opening) is provided at one end of the housing body 110 in the first direction (X direction), and an opening 114 (second opening) is provided at the other end (opposite side). The openings 113 and 114 are sealed by sealing plates 120 and 130 respectively.

[0061] A negative terminal 300A is provided on the sealing plate 120, and a positive terminal 300B is provided on the sealing plate 130. The negative terminal 300A is electrically connected to the negative terminal of the electrode body 200, and the positive terminal 300B is electrically connected to the positive terminal of the electrode body 200. The positions of the negative terminal 300A and the positive terminal 300B can be changed appropriately.

[0062] An injection hole 140 is provided on the sealing plate 130. The injection hole 140 has a diameter capable of injecting electrolyte into the interior of the housing 100. The injection hole 140 is sealed by a sealing member (not shown). As a sealing member, for example, a blind rivet or other metal component can be used. The position of the injection hole 140 can be appropriately changed.

[0063] Sealing plates 120 and 130 have a generally rectangular shape with the Y direction being the shorter side and the Z direction being the longer side. The term "generally rectangular shape" includes both a rectangular shape and shapes that are substantially rectangular, such as those with rounded corners. Sealing plates 120 and 130 are made of metal. Specifically, sealing plates 120 and 130 are made of aluminum, aluminum alloy, iron, or iron alloy.

[0064] like Figure 6As shown, the housing 100 houses the electrode body 200. The electrode body 200 is housed within the housing 100 along with an electrolyte (not shown) with its long side parallel to the X direction. A solid electrolyte may also be used instead of a liquid electrolyte.

[0065] The electrode body 200 can be a stacked electrode body formed by alternating layers of negative and positive plates through a diaphragm, or a wound electrode body formed by winding strip-shaped negative and positive plates together through a strip-shaped diaphragm.

[0066] The electrode body 200 includes a generally rectangular main body, a negative electrode tab assembly 200A, and a positive electrode tab assembly 200B. The negative electrode tab assembly 200A is located at the end of the electrode body 200 on one side in the X direction (the sealing plate 120 side). The positive electrode tab assembly 200B is located at the end of the electrode body 200 on the other side in the X direction (the sealing plate 130 side).

[0067] The current collector 400 includes a negative current collector 400A and a positive current collector 400B. The electrode body 200 is electrically connected to the negative terminal 300A and the positive terminal 300B via the negative current collector 400A and the positive current collector 400B.

[0068] The configuration of the electrode terminal 300 and the current collector 400 is not limited to that in Figures 1-6 The configuration illustrated, for example, the sealing plate 130 can also function as the positive terminal 300B.

[0069] (Method for manufacturing the housing 100)

[0070] like Figure 7 , Figure 8 As shown, thin-walled portions 12A (first thin-walled portion) and 12B (second thin-walled portion) are formed by preparing a strip of metal plate 10 having a surface 11A (first surface) and a back surface 11B (second surface) and providing recesses 13A (first recess) and 13B (second recess) on surface 11A. Recesses 13A and 13B are formed, for example, by performing roll forming or stamping on the metal plate 10. The wall thickness of the metal plate 10, which moves during the forming of recesses 13A and 13B, can extend only outwards from the metal plate 10. Figure 7 , Figure 8 The upper and lower ends of the metal plate 10 can be arranged separately, or only towards the inner side of the metal plate 10. Figure 7 , Figure 8 The metal plate 10 can be arranged in two directions: the upper and lower sides of the central side, and the outer and inner sides of the metal plate 10.

[0071] exist Figure 7 , Figure 8In the example, recesses 13A and 13B are formed at the ends of the metal plate 10, and a step portion is formed only on one side (the central side of the metal plate 10) of the recesses 13A and 13B. However, the form of the recesses 13A and 13B is not limited to this. The recesses 13A and 13B may also be formed at a position offset from the end to the central side of the metal plate 10, and a step portion may be formed on both sides of the recesses 13A and 13B.

[0072] A conventional portion 14 is provided between the thin-walled portions 12A and 12B. The stepped portions formed at the edges of the recesses 13A and 13B correspond to the boundaries between the thin-walled portions 12A and 12B and the conventional portion 14.

[0073] Thin-walled portions 12A and 12B have a thickness T1. Conventional portion 14 has a thickness T2. The thickness T1 of thin-walled portions 12A and 12B is smaller than the thickness T2 of conventional portion 14 (T1 < T2). That is, the thickness T2 of conventional portion 14 is larger than the thickness T1 of thin-walled portions 12A and 12B. Figure 7 , Figure 8 In this example, the thickness T2 of the conventional portion 14 is approximately the same as the thickness T3 of the substrate of the metal plate 10. Furthermore, "approximately the same thickness" includes cases where the thicknesses are identical (T2 = T3) and cases where the thicknesses are substantially identical (e.g., T2 / T3 is in the range of 0.95 to 1.05). However, the thickness T2 of the conventional portion 14 may also differ from the thickness T3 of the substrate of the metal plate 10 (e.g., where T2 / T3 is outside the range of 0.95 to 1.05). As an example, the central portion of the first side surface portion 111, where no irregularities or depressions are formed, corresponds to the conventional portion 14.

[0074] like Figure 9 As shown, the plate-shaped member 20 is cut out by cutting (trimming) the metal plate 10 with thin-walled portions 12A and 12B. The plate-shaped member 20 has a rectangular shape including a pair of first end edges 21A and 21B and a pair of second end edges 22A and 22B. The pair of first end edges 21A and 21B extend substantially parallel to each other. The pair of second end edges 22A and 22B extend substantially parallel to each other. The first end edges 21A and 21B and the second end edges 22A and 22B extend in directions that are substantially orthogonal (intersecting) to each other. Here, "substantially parallel" includes the case of parallelism as well as the case of substantial parallelism (e.g., the angle of inclination of one relative to the other is within 5°). "Substantially orthogonal" includes the case of orthogonality as well as the case of substantial orthogonality (e.g., the angle of intersection of one relative to the other is 85° to 95°).

[0075] The first end edge 21A is formed by cutting off the thin-walled portion 12A of the metal plate 10. The first end edge 21B is formed by cutting off the thin-walled portion 12B of the metal plate 10. The first end edges 21A and 21B are preferably formed as a straight line throughout the entire structure.

[0076] Alternatively, a thin-walled portion 12A can be formed and then cut off, followed by the formation of a thin-walled portion 12B, which can then be cut off. Furthermore, the first end edge 21A, the first end edge 21B, the second end edge 22A, and the second end edge 22B can be formed in any order.

[0077] Plate-shaped component 20 from Figure 9 As shown, the plate-shaped component 20 is bent along four bending lines 23A, 23B, 23C, and 23D with surface 11A located on the inner surface side. Thus, the plate-shaped component 20 is bent into a square tube shape. Figure 9 In the example, the second edge 22A, 22B extends roughly parallel to the four bend lines 23A, 23B, 23C, 23D.

[0078] In the plate-shaped component 20, which is bent into a square tube shape, a pair of second end edges 22A and 22B abut against each other. After bending the plate-shaped component 20, the square tube-shaped shell body 110 is formed by joining the second end edges 22A and 22B together. The second end edges 22A and 22B can be joined together, for example, by irradiation with energy lines such as laser welding.

[0079] The areas of the plate-shaped member 20 sandwiched between bending lines 23A and 23B, and between bending lines 23C and 23D, constitute a pair of first side faces 111 in the main body 110. The areas of the plate-shaped member 20 sandwiched between bending lines 23B and 23C constitute a second side face 112A in the main body 110. The areas of the plate-shaped member 20 sandwiched between the second end edge 22A and bending line 23A, and between the second end edge 22B and bending line 23D, constitute a second side face 112B in the main body 110.

[0080] After the electrode body 200 is inserted into the pre-fabricated housing body 110, as Figure 10 As shown, openings 113 and 114 are sealed by sealing plates 120 and 130. Figure 10 The diagram only shows the structure on the side with opening 114 (positive electrode side), but the same structure can also be used on the side with opening 113 (negative electrode side).

[0081] When forming the joint 160 between the shell body 110 and the sealing plate 130, from arrow A ( Figure 10 The laser energy line is irradiated in the direction of ( ). Figure 10 In this example, the sealing plate 130 is positioned by abutting against the stepped surface at the boundary between the thin-walled portion 12B and the regular portion 14. However, the sealing plate 130 may not necessarily abut against the stepped surface. Alternatively, the sealing plate 130 may have a portion that fits into the inner periphery of the regular portion 14.

[0082] As described above, by irradiating the energy line toward the step portion between the thin-walled portion 12B and the conventional portion 14, the energy line is blocked by the step portion, suppressing the energy line from reaching the interior of the housing body 110, thus protecting the electrode body 200.

[0083] According to the manufacturing method of the housing body 110 according to this embodiment, when the housing body 110 with openings 113 and 114 at both ends in the X direction is manufactured, the thin-walled portions 12A and 12B can be stably formed. In particular, the dimensions (thickness and length) of the thin-walled portions 12A and 12B can be stabilized. As a result, the connection between the housing body 110 and the sealing plates 120 and 130 can be stably performed, and a secondary battery 1 with excellent reliability of the joint 160 (such as the sealing performance of the housing 100) can be obtained.

[0084] The thickness (T1) of the thin-walled portions 12A and 12B is preferably 0.2 mm or more, more preferably 0.4 mm or more, and even more preferably 0.6 mm or more. Furthermore, T1 is preferably 1.0 mm or less, more preferably 0.7 mm or less.

[0085] The thickness (T2) of the conventional section 14 is greater than T1, preferably 0.4 mm or more, more preferably 0.6 mm or more. In addition, T2 is preferably 1.5 mm or less, more preferably 1.2 mm or less, and even more preferably 1.0 mm or less.

[0086] By setting T1 and T2 within the aforementioned range, the strength of the thin-walled portions 12A and 12B can be sufficiently ensured, and a step of suitable height can be formed between the thin-walled portions 12A and 12B and the conventional portion 14. However, T1 and T2 are not limited to the aforementioned range.

[0087] The height (T2-T1) of the stepped portion between the thin-walled portions 12A and 12B and the conventional portion 14 is preferably 0.2 mm or more, and more preferably 0.3 mm or more. This allows for greater stability in the position or orientation of the sealing plates 120 and 130, and effectively prevents the energy lines used to form the joint 160 from reaching the interior of the housing body 110. Therefore, the sealing plates 120 and 130 can be stably joined, and the electrode body 200 housed within the housing body 110 can be effectively protected.

[0088] The height of the step portion (T2-T1) is preferably less than 0.5 mm. This prevents the thickness T1 of the thin-walled portions 12A and 12B from being too small, and the thickness T2 of the conventional portion 14 from being too large, thus protecting the electrode body 200 and achieving the positioning effect of the sealing plates 120 and 130 at the step portion.

[0089] The thickness (T1) of the thin-walled portions 12A and 12B may also be locally different in the circumferential direction of the openings 113 and 114 of the main body 110. For example, the thickness (T11) of the thin-walled portions 12A and 12B of the straight sections of the generally rectangular openings 113 and 114 and the thickness (T12) of the thin-walled portions 12A and 12B of the corner sections of the openings 113 and 114 may also be different from each other.

[0090] For example, by making the thickness (T12) of the thin-walled portions 12A and 12B at the corners of openings 113 and 114 smaller than the thickness (T11) of the thin-walled portions 12A and 12B at the straight sections (T12 < T11), the height of the stepped portions (T2 - T1) at the four corners of openings 113 and 114 can be increased, thereby providing more stable support for the sealing plates 120 and 130. The difference in thickness (T11 - T12) is preferably less than 0.3 mm, and more preferably less than 0.1 mm. As a result, when forming the joint 160, the increase in the gap between the housing body 110 and the sealing plates 120 and 130 can be suppressed, thereby enabling a more stable formation of the joint 160.

[0091] Alternatively, the thickness (T1) of the thin-walled portions 12A and 12B may be different in the portion corresponding to the first side portion 111 (long side) and the portion corresponding to the second side portion 112 (short side).

[0092] When T1 on the long side is larger than T1 on the short side, it is easier to increase the weld nugget when welding (joining) the shell body 110 and the sealing plates 120 and 130 on the long side, and the length of the larger weld nugget portion can be extended. On the other hand, since the step between the thin-walled portions 12A and 12B and the conventional portion 14 can be increased on the short side, the sealing plates 120 and 130 can be stably supported at the step, thereby stably forming the joint portion 160.

[0093] When T1 on the short side is larger than T1 on the long side, the step between the thin-walled portions 12A and 12B and the conventional portion 14 can be increased on the long side, thus increasing the step area to more stably support the sealing plates 120 and 130. Therefore, the joint 160 can be formed more stably.

[0094] A recess 15 is formed on the back surface 11B of the metal plate 10. The thin-walled region of the metal plate 10 formed by the recess 15 constitutes the exhaust valve 150 of the housing 100. The recess 15 is preferably provided at a position corresponding to the second side surface portion 112, which is the short side surface. On the short side surface (second side surface portion 112), the amount of deformation caused by bending of the metal plate 10 (plate-shaped member 20) is reduced compared to the long side surface (first side surface portion 111). Therefore, by providing the recess 15 at a position corresponding to the short side surface after bending, the working pressure of the exhaust valve 150 can be made more stable.

[0095] The machining of the recess 15 for forming the exhaust valve 150 can be performed on the metal plate 10 before cutting (before the plate-shaped member 20 is cut out), or on each plate-shaped member 20 cut from the metal plate 10. When the recess 15 is formed on each plate-shaped member 20, the machining of forming the recess 15 can be performed before bending the plate-shaped member 20, or on the plate-shaped member 20 that is in the middle of the bending process (for example, only a portion of the bending lines among multiple bending lines have been bent), or after bending the plate-shaped member 20 into a square tube shape.

[0096] The planar shape of the recess 15 (the shape when viewed from a direction orthogonal to the extension direction of the metal plate 10) can be appropriately changed, for example, it can be a strip, a cross, a roughly circular shape, a roughly polygonal shape, etc.

[0097] (Modified example)

[0098] exist Figure 11 In the modified example shown, the dimensions (L1, L2) of the thin-walled portion 12A in the extension direction (arrow DR1 direction) of the second end edges 22A and 22B vary depending on the position of the plate member 20 in the extension direction of the first end edge 21A.

[0099] like Figure 11 As shown, the thin-walled portion 12A includes a region 12A1 (first region) that overlaps with the bending lines 23A, 23B, 23C, and 23D, and a region 12A2 (second region) that is separated from the bending lines 23A, 23B, 23C, and 23D in the direction of arrow DR1. Region 12A1 has a length L1 (first length) in the direction of arrow DR2, and region 12A2 has a length L2 (second length) in the direction of arrow DR2, where L1 is greater than L2 (L1 > L2).

[0100] exist Figure 11 The diagram only shows the structure on the thin-walled portion 12A side, but the same structure can also be used on the thin-walled portion 12B side. That is, the thin-walled portion 12B can also be constructed similarly to... Figure 11The thin-walled portion 12A shown is similar in that the length (third length) of the thin-walled portion 12B in the region (third region) overlapping with the bending lines 23A, 23B, 23C, 23D is greater than the length (fourth length) of the thin-walled portion 12B in the region (fourth region) separating from the bending lines 23A, 23B, 23C, 23D.

[0101] Through such Figure 11 As in the example, at the locations where they overlap with bending lines 23A, 23B, 23C, and 23D, the thin-walled portions 12A and 12B are made relatively longer. This allows for the suppression of positional variations (deviations in the direction of arrow DR2 in the circumferential direction of openings 113 and 114) at the boundary surfaces (step surfaces) between the thin-walled portions 12A and 12B and the regular portions 14 caused by interference between the regular portions 14 in the bending portions of the plate-shaped member 20. As a result, the reliability of the joint 160 between the housing body 110 and the sealing plates 120 and 130 can be further improved.

[0102] L1 (first length) is preferably 1 mm or more, more preferably 2 mm or more, and more preferably 4 mm or more. L1 is preferably 10 mm or less, more preferably 8 mm or less, and even more preferably 6 mm or less.

[0103] L2 (second length) is preferably 0.5 mm or more, more preferably 1 mm or more, and more preferably 2 mm or more. L2 is preferably 5 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less.

[0104] L1 / L2 is preferably 1.5 or higher, more preferably 2.0 or higher. Furthermore, L1 / L2 is preferably 3.0 or lower. By setting L1 / L2 within the above range, it is possible to ensure ease of handling (chip removal) of excess material during the processing of the thin-walled portion 12A, and to achieve effects such as suppressing changes in the position of the boundary surface (step surface) between the thin-walled portions 12A, 12B and the conventional portion 14. However, L1 and L2 are not limited to the above ranges.

[0105] exist Figure 12 In the example, in the region (region 1) overlapping with bend lines 23A, 23B, 23C, and 23D, a thin-walled portion 12C is integrally formed throughout the direction of arrow DR2. That is, thin-walled portions 12A and 12B are connected via thin-walled portion 12C. Figure 12 In the examples, it is also possible to connect with Figure 11 The same example further improves the reliability of the joint 160 between the housing body 110 and the sealing plates 120, 130.

[0106] exist Figure 13In the modified example shown, slit holes 16A and 16B are pre-provided on the metal plate 10 located outside the cutting area of ​​the plate-shaped member 20. The slit holes 16A and 16B are provided by stamping the metal plate 10.

[0107] according to Figure 13 In the modified example shown, when the wall thickness moves outward from the metal plate 10 due to the processing used to form the recesses 13A and 13B, the wall thickness can be distributed more stably. Therefore, in the cut plate-shaped component 20, the thickness of the thin-walled portions 12A and 12B can be made more stable.

[0108] exist Figure 14 In the modified example shown, a thick-walled portion 17A (first thick-walled portion) adjacent to the thin-walled portion 12A and a thick-walled portion 17B (second thick-walled portion) adjacent to the thin-walled portion 12B are formed on both sides of the conventional portion 14 in the metal plate 10. The thickness (T1) of the thin-walled portions 12A and 12B is smaller than the thickness of the substrate of the metal plate 10, i.e., the thickness (T3) of the conventional portion 14, and the thickness (T2) of the thick-walled portions 17A and 17B is larger than the thickness (T3) of the conventional portion 14 (T2 > T3 > T1).

[0109] Figure 14 The structure shown can be obtained by displacing at least a portion of the wall thickness of the metal plate 10, which is moved by the process of forming the recesses 13A and 13B, toward the inside of the metal plate 10.

[0110] according to Figure 14 The modified example shown can ensure the height (T2-T1) of the stepped portion caused by the recesses 13A and 13B, and can make the thickness (T3) of the conventional portion 14 thinner, thus increasing the volume of the housing body 110 and achieving a lightweight housing body 110.

[0111] (Manufacturing method of secondary batteries)

[0112] like Figure 15 As shown in the flowchart, the manufacturing method of the secondary battery 1 includes a process for manufacturing the casing body 110 (S10), a process for manufacturing the electrode body 200 (S20), a process for housing the electrode body 200 (S30~S70), an inspection process (S80), and a liquid injection process (S90).

[0113] In the manufacturing process (S10) of the housing body 110, thin-walled portions 12A and 12B are formed on the metal plate 10 (S11), a plate-shaped component 20 is formed by cutting the metal plate 10 (S12), the plate-shaped component 20 is bent into a square tube shape (S13), and the second end edges 22A and 22B are joined together (S14).

[0114] After the electrode body 200 is formed (S20), the negative current collector 400A and the positive current collector 400B are connected to the electrode body 200 (S30). Next, the negative current collector 400A is electrically connected to the negative terminal 300A (S40).

[0115] Next, with the positive current collector 400B side facing forward, the electrode body 200 is inserted into the housing body 110 (S50). Then, the positive current collector 400B is electrically connected to the positive terminal 300B (S60).

[0116] Then, the openings 113 and 114 of the housing body 110 are sealed by sealing plates 120 and 130 (S70). The opening 113 of the housing body 110 is sealed by sealing plate 120, and the opening 114 of the housing body 110 is sealed by sealing plate 130. Thus, the electrode body 200 is housed in the housing 100.

[0117] The above procedures are not limited to Figure 15 The sequence shown. For example, the manufacturing processes (S10, S20) for the housing body 110 and the electrode body 200 can be in the same order as... Figure 15 Conversely, if the electrode body 200 is manufactured first, the manufacturing processes of the housing body 110 (S10) and the electrode body 200 (S20) can be performed simultaneously and in parallel. Furthermore, the order of S30 to S60 can be appropriately modified. For example, the electrode body 200 can be inserted into the housing body 110 with the negative current collector 400A side as the leading edge.

[0118] After the above procedures, leak checks and other inspections are performed (S80). Next, electrolyte is injected into the housing 100 through the injection hole 140 provided in the sealing plate 130 (S90). After that, the injection hole 140 is sealed, and the secondary battery 1 is completed.

[0119] While embodiments of the present invention have been described, it should be understood that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the invention is shown by the technical solutions and is intended to include all modifications within the meaning and scope of equivalent technical solutions.

Claims

1. A method for manufacturing a battery casing, characterized in that, It has the following processes, namely: The process of forming a first thin-walled portion in a metal plate by providing a first recess on the first surface of the metal plate, and forming a second thin-walled portion in the metal plate by providing a second recess on the first surface of the metal plate; The metal sheet cutting process cuts the metal sheet into a generally rectangular shape having a pair of first end edges and a pair of second end edges, wherein one of the pair of first end edges is formed by cutting the first thin-walled portion, and the other of the pair of first end edges is formed by cutting the second thin-walled portion. Following the metal sheet cutting process, the metal sheet is bent into a cylindrical shape such that one of the pair of second end edges abuts against the other of the pair of second end edges, and the first surface becomes the inner surface side; and The process of joining one of the pair of second end edges to the other of the pair of second end edges after the process of bending the metal plate into a cylindrical shape.

2. The method for manufacturing a battery casing according to claim 1, characterized in that, It also includes a step of forming an exhaust valve with a recess on a second surface of the metal plate opposite to the first surface.

3. The method for manufacturing a battery casing according to claim 2, characterized in that, The process of forming the exhaust valve includes the step of forming the recess on the second surface of the metal plate before bending.

4. The method for manufacturing a battery casing according to claim 2, characterized in that, The process of forming the exhaust valve includes the step of forming the recess on the second surface midway through the process of bending the metal plate.

5. The method for manufacturing a battery casing according to any one of claims 1 to 4, characterized in that, The process of bending the metal sheet into a cylindrical shape includes bending the metal sheet along a straight bending line extending parallel to the pair of second end edges. The first thin-walled portion includes a first region that overlaps with the bending line and a second region that is separated from the bending line in the direction extending from the pair of first end edges. The first region has a first length in the direction in which the pair of second end edges extend, and the second region has a second length in the direction in which the pair of second end edges extend. The first length is greater than the second length.

6. The method for manufacturing a battery casing according to claim 5, characterized in that, The second thin-walled portion includes a third region that overlaps with the bending line and a fourth region that is separated from the bending line in the direction extending from the pair of first end edges. The third region has a third length in the direction extending from the pair of second end edges, and the fourth region has a fourth length in the direction extending from the pair of second end edges. The third length is greater than the fourth length.

7. The method for manufacturing a battery casing according to any one of claims 1 to 4, characterized in that, The metal plate is bent into a square tube shape.

8. The method for manufacturing a battery casing according to any one of claims 1 to 4, characterized in that, A conventional portion is formed in the metal plate between the first thin-walled portion and the second thin-walled portion. The thickness of the first thin-walled portion and the second thin-walled portion is less than the thickness of the substrate of the metal plate. The thickness of the conventional section is approximately the same as the thickness of the substrate of the metal plate.

9. The method for manufacturing a battery casing according to any one of claims 1 to 4, characterized in that, The metal plate has a first thick-walled portion adjacent to the first thin-walled portion and a second thick-walled portion adjacent to the second thin-walled portion. The thickness of the first thin-walled portion and the second thin-walled portion is less than the thickness of the substrate of the metal plate. The thickness of the first thick-walled portion and the second thick-walled portion is greater than the thickness of the substrate of the metal plate.

10. A method for manufacturing a battery, characterized in that, It has the following processes, namely: The process of forming a first thin-walled portion in a metal plate by providing a first recess on the first surface of the metal plate, and forming a second thin-walled portion in the metal plate by providing a second recess on the first surface of the metal plate; The metal sheet cutting process cuts the metal sheet into a generally rectangular shape having a pair of first end edges and a pair of second end edges, wherein one of the pair of first end edges is formed by cutting the first thin-walled portion, and the other of the pair of first end edges is formed by cutting the second thin-walled portion. After the metal sheet cutting process, the metal sheet is bent into a cylindrical shape in such a way that one of the pair of second end edges abuts against the other of the pair of second end edges and the first surface becomes the inner surface side. After the process of bending the metal plate into a cylindrical shape, the process of joining one of the pair of second end edges with the other of the pair of second end edges to form a cylindrical battery casing. The process of inserting the electrode body into the cylindrical battery casing; The process of sealing the first opening on one side of the cylindrical battery casing using a first sealing plate; and The process of sealing the second opening on the other side of the cylindrical battery casing using the second sealing plate.

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