Battery and manufacturing method thereof

Abstract

The battery 10 includes a battery can 100 having a cylindrical portion 120 with an opening edge at one end and a bottom portion 130 that closes the other end of the cylindrical portion, an electrode body 200 housed in the cylindrical portion, and a sealing member 300 fixed to the cylindrical portion so as to seal the opening of the opening edge portion 110. The sealing member 300 includes a lid portion 330 that covers the opening of the opening edge portion 110. A first engagement portion 401 is formed at the end of the cylindrical portion 120 on the opening edge portion 110 side, and a second engagement portion 402 is formed at the end of the lid portion 330 on the outer periphery side, and a first surface of the first engagement portion 401 and a second surface of the second engagement portion 402 are joined in an overlapping state.

Description

[Technical field]

[0001] The present invention relates to a battery and a method for manufacturing the same. [Background technology]

[0002] As a method for sealing the opening of a battery can after housing the electrode body in the battery can, there is known a method, as disclosed in Patent Document 1, in which the vicinity of the opening of the battery case (battery can) is narrowed inward to form an annular groove, a gasket and a sealing plate are placed on the upper part of the groove, and the open edge of the battery case is crimped to the sealing plate via the gasket to form a crimped portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-105933 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a battery having the above-mentioned groove and crimping portion, the sealing member is placed on the groove, and the crimping portion is formed on the sealing member via a gasket, so the dimension in the height direction of the battery near the sealing plate tends to be large, which limits the increase in the energy density of the battery. [Means for solving the problem]

[0005] One aspect of the present invention relates to a battery comprising: a cylindrical portion having an opening edge at one end and a bottom that closes the other end of the cylindrical portion; an electrode body contained in the cylindrical portion; and a sealing member fixed to the cylindrical portion so as to seal the opening of the opening edge, wherein the sealing member includes a lid portion that covers the opening, a first engagement portion is formed at the end of the cylindrical portion on the opening edge side, and a second engagement portion is formed at an end of the lid portion on the outer periphery, and a first surface of the first engagement portion and a second surface of the second engagement portion are joined in an overlapping state.

[0006] Another aspect of the present invention relates to a method for manufacturing a battery, the method including: preparing a battery can having a cylindrical portion with an opening edge at one end and a bottom portion that closes the other end of the cylindrical portion; preparing a sealing member having a lid portion that covers at least a portion of an opening of the opening edge portion; and a welding step of welding the sealing member to the battery can, wherein the opening edge portion of the battery can is bent and has a first surface at the opening edge portion that is inclined obliquely with respect to a radial direction of the cylindrical portion, and the lid portion has a second surface at an end portion on the outer circumferential side of the lid portion that is inclined obliquely with respect to an axial direction of the cylindrical portion, and the welding step is a step of placing the sealing member on the battery can in which an electrode body is housed so as to close the opening edge, and overlapping the first surface of the cylindrical portion against the second surface of the lid portion while pressing them together, and joining them by welding. Effect of the Invention

[0007] According to the present invention, a battery with high energy density can be easily realized. The novel features of the present invention are set forth in the appended claims, but the present invention, both in terms of structure and content, together with other objects and features of the present invention, will be better understood from the following detailed description taken in conjunction with the drawings. [Brief description of the drawings]

[0008] [Figure 1A] 5A to 5C are schematic diagrams showing examples of methods for joining a lid portion and an opening edge portion in a battery according to an embodiment of the present invention. [Figure 1B] 5A to 5C are schematic diagrams showing examples of methods for joining a lid portion and an opening edge portion in a battery according to an embodiment of the present invention. [Figure 1C] 5A to 5C are schematic diagrams showing examples of methods for joining a lid portion and an opening edge portion in a battery according to an embodiment of the present invention. [Figure 1D] 5A to 5C are schematic diagrams showing examples of methods for joining a lid portion and an opening edge portion in a battery according to an embodiment of the present invention. [Figure 1E] 5A to 5C are schematic diagrams showing examples of methods for joining a lid portion and an opening edge portion in a battery according to an embodiment of the present invention. [Figure 1F] 5A to 5C are schematic diagrams showing examples of methods for joining a lid portion and an opening edge portion in a battery according to an embodiment of the present invention. [Figure 2A] 5A to 5C are schematic diagrams showing other examples of the method for joining the lid and the opening edge in the battery according to the embodiment of the present invention. [Figure 2B] 5A to 5C are schematic diagrams showing other examples of the method for joining the lid and the opening edge in the battery according to the embodiment of the present invention. [Figure 2C] 5A to 5C are schematic diagrams showing other examples of the method for joining the lid and the opening edge in the battery according to the embodiment of the present invention. [Figure 2D] 5A to 5C are schematic diagrams showing other examples of the method for joining the lid and the opening edge in the battery according to the embodiment of the present invention. [Figure 2E] 5A to 5C are schematic diagrams showing other examples of the method for joining the lid and the opening edge in the battery according to the embodiment of the present invention. [Figure 2F] 5A to 5C are schematic diagrams showing other examples of the method for joining the lid and the opening edge in the battery according to the embodiment of the present invention. [Figure 3A] 10A to 10C are schematic diagrams showing still another example of a method for joining the lid portion and the opening edge portion in the battery according to the embodiment of the present invention. [Figure 3B] 10A to 10C are schematic diagrams showing still another example of a method for joining the lid portion and the opening edge portion in the battery according to the embodiment of the present invention. [Figure 3C] 10A to 10C are schematic diagrams showing still another example of a method for joining the lid portion and the opening edge portion in the battery according to the embodiment of the present invention. [Figure 3D] 10A to 10C are schematic diagrams showing still another example of a method for joining the lid portion and the opening edge portion in the battery according to the embodiment of the present invention. [Figure 3E] 10A to 10C are schematic diagrams showing still another example of a method for joining the lid portion and the opening edge portion in the battery according to the embodiment of the present invention. [Figure 3F] 10A to 10C are schematic diagrams showing still another example of a method for joining the lid portion and the opening edge portion in the battery according to the embodiment of the present invention. [Figure 3G] 10A to 10C are schematic diagrams showing still another example of a method for joining the lid portion and the opening edge portion in the battery according to the embodiment of the present invention. [Figure 3H] 10A to 10C are schematic diagrams showing still another example of a method for joining the lid portion and the opening edge portion in the battery according to the embodiment of the present invention. [Figure 4] 1 is a schematic vertical cross-sectional view of a battery according to a first embodiment of the present invention. [Diagram 5] FIG. 4 is a schematic vertical cross-sectional view of a battery according to a second embodiment of the present invention. [Figure 6] 3 is an enlarged schematic vertical cross-sectional view of a joint between a lid and an opening edge of the battery. FIG. [Figure 7] 4 is a schematic vertical cross-sectional view showing the battery in a state before a lid portion and an opening edge portion are joined together. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The battery according to this embodiment includes a battery can having a cylindrical portion with an opening edge portion at one end and a bottom portion that closes the other end of the cylindrical portion, an electrode body housed in the cylindrical portion, and a sealing member fixed to the cylindrical portion so as to seal the opening of the opening edge portion. The sealing member includes a lid portion that covers the opening.

[0010] Here, the direction in which both ends of the cylindrical portion face each other is defined as the axial direction. For convenience, the direction from the opening edge to the bottom is defined as the downward direction, and the direction from the bottom to the opening edge is defined as the upward direction. In other words, the up-down direction of the battery is defined based on the axial direction of the cylindrical portion when the battery can is stood upright with the bottom facing down. The direction perpendicular to the axial direction is sometimes called the horizontal direction or the radial direction.

[0011] A first engagement portion is formed at the end of the cylindrical portion on the opening edge side, while a second engagement portion is formed at the end of the lid portion on the outer periphery side. A first surface of the first engagement portion and a second surface of the second engagement portion are joined together in an overlapping state.

[0012] The joining can be performed, for example, by welding. The inside of the battery can is sealed by welding, and the lid can be firmly fixed to the battery can. In this case, since it is not necessary to provide a conventional annular groove (also called a reduced diameter portion) and a crimping portion formed on the opening edge portion, the distance between the electrode body and the sealing member can be shortened. For example, it is possible to arrange the electrode body closer to the terminal portion, or to increase the height of the electrode body to a position close to the terminal portion. Therefore, the energy density of the battery can be increased.

[0013] However, when sealing the opening edge by welding, it is necessary to eliminate a gap between the opening edge and the outer peripheral end of the lid to prevent welding defects. Therefore, when sealing the battery can, it is necessary to process the opening edge and the outer peripheral end of the lid into approximately the same shape in the circumferential direction, and high processing accuracy is required.

[0014] In contrast, in the battery of this embodiment, the first surface of the first engagement portion and the second surface of the second engagement portion can be overlapped and joined by welding. That is, the first surface and the second surface are welded in a surface-to-surface contact state, which makes it difficult for a gap to occur between the opening edge portion and the outer peripheral end portion of the lid portion and increases the joining strength. For example, by pressing the second engagement portion against the first engagement portion, the circumferential gap is reduced and the first surface and the second surface can be in surface contact.

[0015] As one aspect of the first engagement portion, the opening edge portion may have a first portion that extends while bending radially toward the outside or inside of the cylindrical portion. In this case, the first portion may form the first engagement portion. Note that "extending while bending" is not limited to extending while bending, but includes a case where the extending portion after bending has a curved shape and the extending direction changes continuously (i.e., extending while curving). This also applies to the second to fourth portions described below.

[0016] Here, the axial direction of the cylindrical portion from the bottom to the opening edge is defined as the Z direction, and the direction perpendicular to the axial direction (radial direction) from the axis of the cylindrical portion to the outer periphery is defined as the r direction. The first part of the opening edge part extends in a bent manner toward the outside or inside of the tube part in the radial direction means that, when a unit vector representing the extension direction of a specific part of the tube part (for example, the axial direction of the tube part) is V0 and a unit vector representing the extension direction of the first part extending in a bent manner from the specific part is V1, the r-direction component of V1 changes from the r-direction component of V0. In this case, when the r-direction component of V1 decreases from the r-direction component of V0, the opening edge part is bent toward the inside in the radial direction, and when it increases, the opening edge part is bent toward the outside in the radial direction. In other words, the opening edge part is bent and extends means that it extends so as to be separated in the radial direction from a virtual straight line extending in the axial direction of the tube part.

[0017] As one embodiment of the second engagement portion, the outer peripheral end of the cover may have a second portion that is bent and extends toward the bottom side or the opening edge side in the axial direction. In this case, the second portion may form the second engagement portion. Here, the second part of the lid part extends in a bent manner toward the bottom side or the opening edge side in the axial direction means that, when a unit vector representing the extension direction of a specific part of the lid part (for example, a direction perpendicular to the axis of the tube part) is W0 and a unit vector representing the extension direction of the second part extending in a bent manner from the specific part is W1, the Z-direction component of W1 changes from the Z-direction component of W0. In this case, when the Z-direction component of W1 decreases from the Z-direction component of W0, the outer peripheral end of the lid part bends toward the bottom side, and when it increases, it bends toward the opening edge side. This also applies to the third and fourth parts described later. In other words, the lid part extends in a bent manner means that it extends in an axial direction away from a virtual straight line extending in a direction perpendicular to the axis of the tube part.

[0018] The bent extension (first portion) is provided on the tubular portion (opening edge portion), so that the tubular portion is easily bent (like a spring) against axial force. Therefore, even if there is a small gap between the first engaging portion and the second engaging portion in a part of the circumferential direction when not pressed, the outer peripheral end of the tubular portion and the lid portion is appropriately deformed by pressing, and the first engaging portion and the second engaging portion can come into contact with each other with the gap between the first surface and the second surface reduced. Therefore, welding defects are reduced by welding the opening edge portion and the outer peripheral end of the lid portion in this state. The lid portion can be provided with a second portion so that the first surface and the second surface overlap in correspondence with the first portion.

[0019] The outer peripheral end of the lid may have a third portion that bends and extends toward the bottom side or the opening edge side in the axial direction of the tube, and a fourth portion that bends and extends from the third portion in the opposite direction to the bending direction of the third portion. In this case, the fourth portion may form the second engagement portion. The bending directions of the third portion and the fourth portion being opposite to each other means that when the third portion bends and extends toward the bottom side, the fourth portion bends and extends toward the opening side, or when the third portion bends and extends toward the opening edge side, the fourth portion bends and extends toward the bottom side. Therefore, the lid provided with the third portion and the fourth portion is bent in a zigzag manner toward the outer peripheral direction. The lid may be bent in a zigzag manner toward the outer peripheral direction, or may be bent in a crank shape.

[0020] In the lid having at least the third portion, the third portion may form the second engagement portion. In other words, the lid having the above-mentioned second portion may be further bent at the end side of the second portion and extend in a direction different from the bending direction of the second portion.

[0021] The third portion may extend along the inner circumferential surface of the cylindrical portion. This suppresses radial positional deviation of the lid portion and minimizes variation in the cross-sectional shape of the joint between the lid portion and the cylindrical portion. This suppresses unevenness in the joint strength.

[0022] Instead of providing the third portion, a rib may be provided on the cover, which is erected on the surface facing the electrode body and extends along the inner circumferential surface of the cylindrical portion. The rib can provide the same effect as when the third portion is extended along the inner circumferential surface of the cylindrical portion.

[0023] The first surface of the first engagement portion and the second surface of the second engagement portion may be inclined obliquely with respect to the radial and axial directions. The inclined first surface may be an outer peripheral surface, an inner peripheral surface, or an end surface of the tubular portion. The inclined second surface may be a surface on the bottom side of the lid portion (inner surface or lower surface), a surface on the opening edge side of the lid portion (outer surface), or an end surface. When the first surface is an end surface of the tubular portion, the second surface may be a surface on the bottom side of the lid portion. When the second surface is an end surface of the lid portion, the first surface may be an inner peripheral surface of the tubular portion.

[0024] The end face of the tube part may be inclined from a plane perpendicular to the extension direction of the opening edge part, and the inclined surface may form a first surface. Alternatively, the end face on the outer periphery side of the cover part may be inclined from a plane perpendicular to the extension direction of the end part on the outer periphery side of the cover part, and the inclined surface may form a second surface. In other words, the end face of the tube part and / or the end face on the outer periphery side of the cover part may be an end face of a metal plate obtained by cutting the metal plate at an angle and / or by processing the cut surface to be inclined.

[0025] The welding method is not particularly limited and may be appropriately selected depending on the materials of the lid and the battery can. Examples of the welding method include laser welding, resistance welding, friction stir welding, brazing, and the like.

[0026] Either the first surface or the second surface may have a region that is exposed to the outside without overlapping with the other surface, which makes it easier to perform laser welding by thermal conduction.

[0027] The sealing member is provided with a terminal portion. The terminal portion can be electrically connected to one electrode (first electrode) of the electrode body. The battery can can be electrically connected to the other electrode (second electrode) of the electrode body. For example, the lid portion is made of metal and has a through hole. In this case, the terminal portion blocks the through hole while being insulated from the lid portion. The insulation and sealing between the terminal portion and the lid portion may be performed by using a gasket, applying an insulating agent to the contact portion between the terminal portion and the lid portion, or insulating the surface of one of the two members.

[0028] The lid is electrically connected to the cylindrical portion of the battery can via the alloy portion. This allows the lid to be electrically connected to the second electrode of the electrode assembly. This makes it possible to take out the voltage of the external terminal connected to the battery can from the upper side (terminal side) of the battery, particularly from the top plate portion of the lid.

[0029] In a typical battery, the terminal portion functions as the external terminal of the first electrode (e.g., positive electrode) of the battery, and the battery can functions as the external terminal of the second electrode (e.g., negative electrode). When connecting external lead wires to each external terminal, one external lead wire is led out from the top surface of the battery, and the other external lead wire is led out from the bottom surface of the battery. In this case, space for wiring is required above and below the battery.

[0030] In contrast, in the battery of this embodiment, the lid can function as an external terminal of the second electrode connected to the battery can. Therefore, current can be collected from both the first electrode and the second electrode from the upper side (terminal side) of the battery. Therefore, the space (wiring space) for wiring the leads connected to each external terminal only needs to be present on the terminal side, and the wiring space can be saved.

[0031] The method for manufacturing a battery according to the present embodiment includes, for example, (i) a step of preparing a battery can having a tube portion having an opening edge portion at one end and a bottom portion closing the other end of the tube portion, (ii) a step of preparing a sealing member having a lid portion covering the opening of the opening edge portion, and (iii) a welding step of welding the sealing member to the battery can. At this time, the battery can prepared in the step (i) has a bent opening edge portion and a first surface inclined obliquely with respect to the radial direction of the tube portion at the opening edge portion. The lid portion prepared in the step (ii) has a second surface inclined obliquely with respect to the axial direction of the tube portion at the end portion on the outer periphery side of the lid portion. The above-mentioned (iii) welding step may be a step of placing the sealing member on the battery can containing the electrode body so as to close the opening edge, and overlapping the first surface of the tube portion against the second surface of the lid portion while pressing them together, and joining them by welding.

[0032] BEST MODE FOR CARRYING OUT THE DISCLOSURE Hereinafter, a battery according to an embodiment of the present invention will be specifically described with reference to the drawings, but the present invention is not limited thereto.

[0033] [First embodiment] 1 to 3 are schematic diagrams showing an example of a method for joining the lid portion 330 to the opening edge portion 110 of the tube portion 120 by welding in the battery according to this embodiment. FIG. 1 (FIGS. 1A to 1F) shows an example in which the end portion of the opening edge portion 110 is bent radially outward. FIG. 2 (FIGS. 2A to 2F) shows an example in which the end portion of the opening edge portion 110 is bent radially inward. FIG. 3 (FIGS. 3A to 3H) shows an example in which the opening edge portion 110 has a straight shape without a bent portion.

[0034] 1 to 3, a first engagement portion 401 is formed at an end of the opening edge portion 110. A second engagement portion 402 is formed at an end on the outer circumferential side of the lid portion 330. The first engagement portion 401 has a first surface S1, and the second engagement portion 402 has a second surface S2. The first surface S1 and the second surface S2 come into surface contact with each other as the lid portion 330 is pressed against the tube portion 120 during welding.

[0035] 1A to 1F, the opening edge portion 110 has a first portion 411 at its end portion that is bent and extends radially outward. The first portion 411 forms a first engagement portion 401. In FIGS. 1A to 1F, the first surface S1 is a part of the inner circumferential surface of the cylindrical portion, and is inclined obliquely with respect to the axial direction and the radial direction. Corresponding to the first surface S1, the second surface S2 is also inclined obliquely with respect to the axial direction and the radial direction.

[0036] In Figures 1A, 1B, 1D and 1E, the second surface S2 is a part of the bottom surface (lower surface) of the lid. In Figure 1C, the second surface S2 is an end surface of the lid, which is inclined from a plane perpendicular to the extension direction (radial direction) of the outer peripheral end of the lid. As a result, the second surface S2 is inclined obliquely with respect to the axial direction and radial direction. In Figure 1F, the second surface S2 is a part of the curved outer surface (upper surface) of the lid.

[0037] 1A, 1D, and 1E, the outer peripheral end of the cover 330 has a second portion 412 that bends and extends toward the opening edge in the axial direction of the cylindrical portion. The second portion 412 forms a second engagement portion 402.

[0038] In Fig. 1B, the outer peripheral end of the lid portion 330 has a third portion 413 that bends and extends toward the bottom side in the axial direction of the tube portion, and a fourth portion 414 that bends and extends from the third portion 413 in the opposite direction to the bending direction of the third portion. In other words, the end of the lid portion 330 is folded back on the lower surface side of the lid portion 330 to form the fourth portion 414. The fourth portion 414 forms the second engagement portion 402. With the configuration of Fig. 1B, it is possible to expand the space inside the battery can 100.

[0039] 1F, the outer peripheral end of the lid portion 330 bends and extends toward the bottom side in the axial direction of the tube portion, and then further bends and extends toward the inside in the radial direction, so that the outer surface of the fifth portion 415, which is the bent end of the lid portion, comes into contact with the first surface S1, which is a part of the inner peripheral surface of the opening edge portion 110. That is, the fifth portion 415 forms the second engagement portion 402.

[0040] In Fig. 1E, a portion of the outer peripheral region of the second surface S2 is exposed to the outside without overlapping with the first surface S1 even during welding, whereas in Fig. 1F, a portion of the outer peripheral region of the first surface S1 is exposed to the outside without overlapping with the second surface S2 even during welding.

[0041] In Fig. 1A to Fig. 1F, the lid portion 330 can be joined to the opening edge portion 110 of the tube portion 120 by welding. Laser welding can be used for the welding. When performing laser welding, in the example of Fig. 1A to Fig. 1D, butt welding is possible by irradiating a laser beam from an obliquely upward direction. Also, butt welding and lap welding are possible by irradiating a laser beam from above. In Fig. 1E, for example, butt welding and lap welding are possible by irradiating a laser beam from the side. In Fig. 1F, for example, butt welding is possible by irradiating a laser beam from above.

[0042] In Fig. 2A to Fig. 2F, the opening edge portion 110 has a first portion 411 that is bent and extends radially inward at its end. The first portion 411 forms a first engagement portion 401. In the example of Fig. 2A to Fig. 2E, the first surface S1 is an end surface of the tube portion. In the example of Fig. 2F, the first surface S1 is an outer peripheral surface of the first portion 411 of the opening edge portion 110. The first surface S1 is inclined obliquely with respect to the axial direction and the radial direction because the end of the opening edge portion 110 is bent. Corresponding to the first surface S1, the second surface S2 is also inclined obliquely with respect to the axial direction and the radial direction.

[0043] In Figures 2A, 2B, and 2D to 2F, the second surface S2 is the inner surface (lower surface) on the bottom side of the lid. In Figure 2C, the second surface S2 is the end surface of the lid, which is inclined from a plane perpendicular to the extension direction (radial direction) of the outer peripheral end of the lid. As a result, the second surface S2 is inclined obliquely with respect to the axial direction and radial direction.

[0044] 2A, 2D, and 2E, the end of the cover 330 has a second portion 412 that is bent and extends toward the opening edge side in the axial direction of the cylindrical portion. The second portion 412 forms the second engagement portion 402.

[0045] In the example of Fig. 2B, the end of the lid portion 330 has a third portion 413 that bends and extends toward the bottom side in the axial direction of the tube portion, and a fourth portion 414 that bends and extends from the third portion 413 in the opposite direction to the bending direction of the third portion. The fourth portion 414 forms the second engagement portion 402. In the configuration of Fig. 2B, it is possible to increase the space inside the battery can 100 compared to the configuration of Fig. 2E and the like.

[0046] 2F, the end of the lid 330 has a third portion 413 that bends and extends toward the opening edge side (above the battery) in the axial direction of the tube portion, and a fourth portion 414 that bends and extends from the third portion 413 in the opposite direction to the bending direction of the third portion. The fourth portion 414 forms the second engagement portion 402. This configuration makes it easy to expand the area where the lid and the opening edge overlap, and allows the lid to stably engage with the opening edge without increasing the radial dimension of the battery.

[0047] In Fig. 2E, a portion of the outer peripheral region of the second surface S2 is exposed to the outside without overlapping with the first surface S1 even during welding, whereas in Fig. 2F, a portion of the outer peripheral region of the first surface S1 is exposed to the outside without overlapping with the second surface S2 even during welding.

[0048] 2A to 2F, the lid portion 330 can be joined to the opening edge portion 110 of the tube portion 120 by welding. Laser welding can be used for the welding. When performing laser welding, butt welding is possible by irradiating a laser beam from an obliquely upward direction in FIGS. 2A to 2D. Also, butt welding and lap welding are possible by irradiating a laser beam from above.

[0049] In Fig. 2E, for example, by irradiating a laser beam from the side, butt welding is possible. In Fig. 2F, for example, by irradiating a laser beam from the side, butt welding and lap welding are possible.

[0050] In the examples of Figures 3A to 3H, the first surface S1 is an end surface of the tube portion. However, in Figures 3B, 3C, 3F, and 3G, the end surface of the tube portion is inclined from a plane perpendicular to the extension direction (axial direction) of the opening edge portion, and as a result, the first surface S1 is inclined obliquely with respect to the axial direction and radial direction. Corresponding to the first surface S1, the second surface S2 is also inclined obliquely with respect to the axial direction and radial direction.

[0051] In the examples of Figures 3A, 3C to 3E, 3G, and 3H, the second surface S2 is the surface (inner surface) on the bottom side of the lid. In the examples of Figures 3B and 3F, the second surface S2 is the end surface of the lid, and the end surface of the lid is inclined from a plane perpendicular to the extension direction (radial direction) of the outer peripheral end of the lid. As a result, the second surface S2 is inclined obliquely with respect to the axial direction and radial direction.

[0052] 3A to 3D, the end of the lid portion 330 has a third portion 413 that is bent and extends toward the opening edge side (above the battery) in the axial direction of the tube portion, and a fourth portion 414 that is bent and extends from the third portion 413 in the opposite direction to the bending direction of the third portion. The fourth portion 414 forms the second engagement portion 402. The third portion 413 extends along the inner circumferential surface of the tube portion 120, and the fourth portion 414 extends outward from the third portion 413 in the radial direction of the tube portion. In other words, it can be said that a crank portion is formed at the end of the lid portion 330 in FIGS. 3A to 3D.

[0053] 3E to 3H, ribs 403 are provided on the surface of lid 330 facing the electrode body (not shown). Ribs 403 extend from the lid toward the electrode body along the inner circumferential surface of the cylindrical portion of lid 330. In Fig. 3G, the end of the lid has a second portion 412 that bends and extends toward the opening edge side (above the battery) in the axial direction of the cylindrical portion, and second portion 412 forms second engagement portion 402.

[0054] In Figs. 3C, 3D, 3G and 3H, a partial region on the outer circumferential side of the first surface S1 does not overlap with the second surface S2 even during welding and is exposed to the outside.

[0055] 3A to 3H, the lid portion 330 can be joined to the opening edge portion 110 of the tube portion 120 by welding. Laser welding can be used for the welding. When performing laser welding, in the examples of Fig. 3A and Fig. 3E, lap welding is possible by irradiating a laser beam from above. In the examples of Fig. 3B to Fig. 3D and Fig. 3F to Fig. 3H, for example, either lap welding or butt welding is possible.

[0056] 3A to 3H, an O-ring made of an insulating material may be provided on the lid portion at a portion facing the inner circumferential surface of the cylindrical portion (i.e., on the outer circumferential surface of third portion 413 or rib 403). This makes it possible to prevent metal dust from entering the battery can due to friction with the lid portion when the lid portion is inserted into the opening edge portion. 1 to 3, in order to selectively explain the contact state between the lid and the opening edge, only the lid and the tube are shown in the drawings. However, the configurations of the terminals and sealing members such as the gasket described below are naturally also applicable to the configurations disclosed in Figs. 1 to 3.

[0057] Fig. 4 is a schematic vertical cross-sectional view of the battery 10 according to this embodiment. Note that Fig. 4 emphasizes the cylindrical portion of the battery, particularly the state near the opening edge portion 110. The dimensional ratios between the elements of the components such as the terminal portion 310, the gasket 320, and the lid portion 330 may not match the actual dimensional ratios.

[0058] The battery 10 has a cylindrical shape and includes a cylindrical, bottomed battery can 100, a cylindrical electrode body 200 housed in the can, and a sealing member 300 that seals the opening of the battery can 100. The battery can 100 has a tube portion 120 that houses the electrode body 200, and a bottom portion 130. The tube portion 120 has an opening edge portion 110 at one end, and the other end is closed by the bottom portion 130. The tube portion 120 includes the opening edge portion 110 and a housing portion 150 that houses the electrode body. The opening of the opening edge portion 110 is closed by the sealing member 300.

[0059] The sealing member 300 has a terminal portion 310, a gasket 320, and a lid portion 330. The lid portion 330 is connected to the opening edge portion 110 of the battery can 100 via a joint portion 420. 1 to 3, the joint 420 can be formed by overlapping the ends of the opening edge 110 and the lid 330 and performing, for example, laser welding. In Fig. 4, the opening edge 110 and the outer peripheral end of the lid 330 are in a state similar to Fig. 1C, and the inner peripheral surface (first surface) of the first portion 411 bending and extending radially inward and the end face (second surface) of the lid 330 are in surface contact in a state inclined obliquely with respect to the axial and radial directions.

[0060] The terminal portion 310 may be, for example, disk-shaped and have an explosion-proof function. Specifically, the terminal portion 310 includes a thick peripheral portion 311 and a central region 312 for ensuring structural strength, and a thin portion 313 for exerting an explosion-proof function. The thin portion 313 is provided in a region between the peripheral portion 311 and the central region 312. An end of a lead wire 210 derived from a positive electrode or a negative electrode constituting the electrode body 200 is connected to the inner surface of the central region 312. Thus, the terminal portion 310 has one terminal function.

[0061] When the internal pressure of the battery can 100 rises, the terminal portion 310 bulges outward, and for example, stress due to tension is concentrated at the boundary between the peripheral portion 311 and the thin-walled portion 313, causing breakage at the boundary. As a result, the internal pressure of the battery can 100 is released, ensuring the safety of the battery 10. Note that an explosion-proof function is not essential to achieving the effects of the present invention.

[0062] Gasket 320 seals between cover portion 330 and terminal portion 310. Gasket 320 has, for example, outer ring portion 321 covering an upper portion of peripheral portion 311 of terminal portion 310, inner ring portion 322 covering a lower portion of peripheral portion 311 of terminal portion 310, and relay ring portion 323 connecting the outer ring portion and the inner ring portion. For example, outer ring portion 321, inner ring portion 322, and relay ring portion 323 of gasket 320 are an integrated molded body.

[0063] The terminal portion 310 and the gasket 320 may be joined to each other. For example, by integrally molding the terminal portion 310 and the gasket 320, a sealing body in which the terminal portion 310 and the gasket 320 are joined to each other is obtained. As a method of integral molding, insert molding can be used. In this case, the shapes of the terminal portion 310 and the gasket 320 are not limited and can be designed to any shape. Furthermore, by integrally molding the terminal portion 310 and the gasket 320, the terminal portion 310 and the gasket 320 can be handled as one component, which makes it easier to manufacture the battery.

[0064] The lid portion 330 has, for example, a ring-shaped plate, a through hole, and a top plate portion 331 that covers the through hole. The through hole is blocked by the terminal portion 310. The lid portion 330 is electrically insulated from the terminal portion 310 by a gasket 320.

[0065] The lid portion 330 is conductive and has the same polarity as the battery can 100. Therefore, the lid portion 330 can have a terminal function with a polarity different from that of the terminal portion 310. Therefore, current can be collected from both electrodes of the battery 10 from the upper surface of the sealing member 300. For example, a first external lead wire 501 can be connected to the top plate portion 331 of the lid portion 330, and a second external lead wire 502 can be connected to the outer surface of the central region 312 of the terminal portion 310.

[0066] The lid 330 may further include a support portion 334. The support portion 334 stands upright from the inner surface (lower surface) of the lid and extends in the axial direction toward the bottom portion 130. The support portion 334 fixes the gasket 320 to the lid 330 with the gap between the lid 330 and the terminal portion 310 sealed. The contour line of the upright portion of the support portion 334 viewed from the axial direction has a shape similar to that of the outer edge of the gasket 320. However, the contour line does not necessarily have to be a closed continuous curve, and may have a region in a part of the circumferential direction where the support portion 334 is not provided. The contour line may be discontinuous in the circumferential direction of the outer circumferential surface of the gasket 320.

[0067] The outer diameter of gasket 320 may be larger than the inner diameter of support portion 334 in an unloaded state. In this case, the side wall portion of gasket 320 is brought into close contact with support portion 334 by press-fitting, thereby sealing the gap between cover portion 330 and terminal portion 310.

[0068] The support portion 334 extends in the axial direction toward the bottom portion 130, and then bends to follow the inner ring portion 322 of the gasket 320, and extends inward toward the central region 312 of the terminal portion 310. This can further improve the sealing performance between the cover portion 330 and the terminal portion 310. The bent and extending portion of the support portion 334 can be formed by crimping a part of the upright support portion 334 toward the inner circumference and bending it. The bent and extending portion does not need to be formed around the entire circumference of the support portion 334, and may be formed intermittently along the circumferential direction.

[0069] A second gasket 350 may be disposed on the outer periphery side of the upright position of the support portion 334. The second gasket 350 may be sandwiched between the lid portion 330 and an upper insulating plate that insulates the electrode body 200 from the opening edge portion 110 and the support portion 334. The second gasket 350 abuts against the electrode body 200 via the upper insulating plate (or directly), thereby suppressing the electrode body 200 from being displaced within the battery can 100. This suppresses mechanical stress from being applied to the lead wire electrically connected to the electrode body 200, or suppresses the electrode and separator in the electrode body 200 from being deformed due to the electrode body 200 colliding with the battery can 100 or the sealing member 300.

[0070] [Second embodiment] The end of the cylindrical portion on the opening edge side and the end of the cover on the outer periphery side may be joined by an alloy portion containing iron and nickel, in which case the nickel content of the alloy portion may be 1.4 mass% or more.

[0071] The battery according to this embodiment includes a battery can having a cylindrical portion with an opening edge portion at one end and a bottom portion that closes the other end of the cylindrical portion, an electrode body housed in the cylindrical portion, and a sealing member fixed to the cylindrical portion so as to seal the opening of the opening edge portion. The sealing member includes a lid portion that covers the opening of the opening edge portion.

[0072] The end of the cylindrical portion on the opening edge side and the end of the lid portion on the outer periphery side are joined by an alloy portion. The joining can be performed, for example, by welding. By welding, the inside of the battery can is sealed and the lid portion can be firmly fixed to the battery can. The lid portion is electrically connected to the cylindrical portion of the battery can via the alloy portion. This allows the lid portion to be electrically connected to the other electrode of the electrode body.

[0073] However, when an alloy part is formed by welding to seal the opening edge of the cylindrical part and the lid part, rust may occur in the alloy part, reducing the hermetic sealability and the sealing pressure resistance, which may result in electrolyte or gas leakage under normal battery usage conditions. For this reason, suppressing rust in the alloy part has been required to realize a battery with high energy density.

[0074] To solve this problem, in the battery of this embodiment, the alloy portion contains iron (Fe) and nickel (Ni). An alloy containing iron and nickel has rust-proofing properties. In particular, when the content of Ni contained in the alloy portion is 1.4 mass% or more, high rust-proofing properties necessary to suppress a decrease in sealing pressure resistance are obtained, and a battery with a high energy density can be realized. More preferably, the content of Ni contained in the alloy portion may be 3 mass% or more. In this case, the decrease in sealing pressure resistance is further suppressed.

[0075] The battery can (tubular portion) and the lid portion may be made of a material containing iron (Fe), such as a steel plate or a stainless steel plate. The battery can (tubular portion) and the lid portion may contain elements other than iron in addition to iron (Fe). Examples of elements other than iron include carbon (C), Cr, Mn, Ni, Co, and Al. The battery can (tubular portion) and / or the lid portion may be an alloy of iron and an element other than iron. The proportion of iron in the battery can (tubular portion) and / or the lid portion may be 50 mass % or more.

[0076] When the alloy part is formed by welding, the alloy part may contain both elements contained in the opening edge part of the cylindrical part of the battery can and elements contained in the outer peripheral end part of the lid part. When the opening edge part and / or the lid part contain iron (Fe), if either the opening edge part and / or the lid part contains nickel (Ni), an alloy part containing iron and nickel may be formed.

[0077] A battery can having a nickel layer formed on its surface by nickel plating may be used. This can improve the rust prevention performance. However, nickel-plated battery cans are usually manufactured by cutting a steel plate that has been nickel-plated in advance, processing it into a cylindrical shape, and then trimming the cylindrical portion on the opening side. In this case, the base metal that is not nickel-plated is exposed on the end surface of the opening edge of the battery can. Even if the end of the opening edge and the end of the lid are welded together in this state to form an alloy part, the iron of the base metal is exposed on the end surface of the opening edge, and there is almost no Ni, so it is difficult to increase the Ni content in the alloy part to 1.4 mass% or more. It is also possible to increase the Ni content in the alloy part to 1.4 mass% or more by subjecting the end face of the opening edge of the manufactured battery can to nickel plating again before welding. However, since the shape of the formed battery can is more complex than that of a single plate, the number of manufacturing steps increases if plating is to be performed while suppressing unevenness. In addition, the volume of the battery can tends to be larger than that of the sealing material, and the manufacturing equipment tends to be large. As a result, the manufacturing cost tends to be high.

[0078] Therefore, in this embodiment, as an example of a method for increasing the Ni content in the alloy part, a nickel layer is formed at least on the outer peripheral end of the lid part by, for example, plating, and the thickness of the nickel layer is made thick. As a result, Ni present in the nickel layer at the outer peripheral end of the lid part is diffused to the opening edge part side by the high temperature during welding, and an alloy part containing Fe and Ni is formed. The Ni content of the alloy layer is controlled by the thickness of the nickel layer formed at the outer peripheral end of the lid part, and it is easy to increase it to 1.4 mass% or more. Note that, when welding the end of the lid part by facing and abutting against the inner peripheral surface of the opening edge part, welding may be performed in a state where the nickel layer of the outer peripheral edge part is formed thicker than the inner peripheral side on the upper surface of the lid part (the surface farther from the bottom of the battery can). The welding method is not particularly limited and may be appropriately selected depending on the materials of the lid and the battery can. Examples of the welding method include laser welding, resistance welding, and friction stir welding.

[0079] The alloy portion may cover the entire end face of the opening edge portion. In this case, the end face of the opening edge portion before welding disappears due to the formation of the alloy portion, and a new end face of the opening edge portion that is not exposed to the outside is formed at the boundary between the alloy portion and the cylindrical portion. Similarly, the alloy portion may cover the entire outer peripheral side end face of the lid portion. In this case, the outer peripheral side end face of the lid portion before welding disappears due to the formation of the alloy portion, and a new end face that is not exposed to the outside is formed at the boundary between the alloy portion and the lid portion.

[0080] Hereinafter, the nickel layer covering the outer peripheral end face of the lid is referred to as the first nickel layer. When the first nickel layer is formed on the outer peripheral end face of the lid before welding, after welding, a part of the outer peripheral end face of the lid may be covered with the alloy part, and the remaining part of the outer peripheral end face of the lid may be covered with the first nickel layer.

[0081] The main surface constituting the outer surface of the lid may be nickel-plated to form a nickel layer covering the main surface. Hereinafter, the nickel layer covering the main surface constituting the outer surface of the lid is referred to as the second nickel layer. At least a part of the first nickel layer is changed into an alloy part by the welding process. When the first nickel layer remains on the outer peripheral end surface of the lid after welding, the thickness of the first nickel layer may be thicker than the thickness of the second nickel layer.

[0082] When a first nickel layer is formed on the outer peripheral end face of the lid portion and a second nickel layer is formed on the main surface of the lid portion, the second nickel layer may be formed in a first region adjacent to the alloy portion and a second region adjacent to the first region and located on the opposite side to the alloy portion. Of these, the second nickel layer formed in the first region may be the first nickel layer remaining after the alloy portion is formed. In this case, the thickness of the second nickel layer may be thicker in the first region than in the second region when viewed from the first main surface side.

[0083] The Ni contained in the alloy part is supplied from the first nickel layer. The alloy part is formed by diffusing Ni from the first nickel layer toward the edge of the opening, so the Ni concentration is higher on the lid side than on the edge of the opening, and the alloy part may have a distribution of Ni concentration.

[0084] The outer peripheral end of the lid may be bent outward (upward) in the axial direction of the tube, and an alloy part may be formed at the tip of the bent protruding wall that faces outward (upward). By facing the joining surface upward, laser welding is made easier. In addition, by keeping the welding point away from the electrode body, the heat applied to the welding part during welding is transferred to the electrode body and / or the electrolyte, and deterioration of the electrode body and / or the electrolyte can be suppressed.

[0085] The battery according to this embodiment can be manufactured, for example, by preparing a battery can in the above-mentioned step (i) of preparing a battery can in which a nickel layer is formed on the side circumferential surface and the bottom surface of the cylindrical portion and no nickel layer is formed on the end surface of the opening edge portion, and by preparing a sealing member in which a nickel layer is formed on at least the end surface of the outer circumferential side of the metal lid portion in step (ii). The nickel layer can be formed, for example, by plating. The thickness of the nickel layer is 3 μm or more. The thickness of the nickel layer is preferably 7 μm or more.

[0086] Then, in the (iii) welding step, the end of the lid on which the nickel layer is formed and the end of the opening edge part not containing nickel are melted, thereby forming an alloy part containing nickel at least on the end face of the opening edge part, and joining the lid and the opening edge part.

[0087] The cylindrical portion may contain iron or an alloy thereof. In this case, in step (i) of preparing a battery can, an iron layer or an iron alloy layer may be exposed on the end face of the opening edge portion. However, in step (ii), a sealing member having a nickel layer formed on the end face on the outer periphery side of the lid portion is prepared, and in step (iii), the ends of the cylindrical portion and the lid portion are welded together to form an alloy portion, so that the entire end face of the opening edge portion can be covered with an alloy portion containing nickel. By controlling the thickness of the nickel layer so that the Ni content in the alloy portion is 1.4 mass% or more, a battery with excellent rust resistance and high energy density is manufactured.

[0088] The nickel layer may be formed by a known plating method, such as electrolytic plating, electroless plating, or sputtering.

[0089] Fig. 5 is a schematic vertical cross-sectional view of a battery 11 according to this embodiment having an alloy part containing nickel. Fig. 6 is a schematic cross-sectional view showing an enlarged joint between the lid part and the opening edge part of the battery 11. Fig. 7 is a schematic view showing the state before the lid part and the opening edge part are joined. Note that Fig. 5 emphasizes the state of the cylindrical part of the battery, particularly the vicinity of the opening edge part 110. The dimensional ratios between the elements of the components such as the terminal part 310, the gasket 320, and the lid part 330 may not match the actual dimensional ratios.

[0090] The battery 11, like the battery 10, has a cylindrical shape and includes a cylindrical, bottomed battery can 100, a cylindrical electrode body 200 housed in the battery can 100, and a sealing member 300 that seals the opening of the battery can 100. The battery can 100 has a tube portion 120 that houses the electrode body 200, and a bottom portion 130. The tube portion 120 has an opening edge portion 110 at one end thereof, and the other end is closed by the bottom portion 130. The tube portion 120 includes the opening edge portion 110 and a housing portion 150 that houses the electrode body. The opening of the opening edge portion 110 is closed by the sealing member 300.

[0091] The sealing member 300 has a terminal portion 310, a gasket 320, and a lid portion 330. The lid portion 330 is connected to the opening edge portion 110 of the battery can 100 via an alloy portion 421.

[0092] In Fig. 7, the ends of the opening edge portion 110 and the lid portion 330 are overlapped and then laser-welded to form the alloy portion 421 shown in Fig. 6. In Fig. 6, both the outer surface S3 and the inner surface S4 of the lid portion 330 are covered with a nickel layer (second nickel layer) 422.

[0093] 7, the inner and outer surfaces of the battery can 100 are nickel-plated, and are covered with a nickel layer 424. However, an end face 110T of the opening edge 110 is not covered with the nickel layer 424, and an iron-containing base metal layer 425 is exposed. On the other hand, an outer peripheral end face 330T of the lid 330 is nickel-plated, and is covered with a nickel layer (first nickel layer) 423.

[0094] When the alloy part 421 is formed by welding, at least a part of the end face 110T of the opening edge part 110 and at least a part of the end face 330T of the lid part 330 disappear. At this time, the boundary surface between the alloy part 421 and the tube part 120 becomes the new end face of the opening edge part 110, and the boundary surface between the alloy part 421 and the lid part 330 becomes the new end face of the lid part 330. In the example of FIG. 6, the alloy part 421 is formed so as to cover the end face of the opening edge part 110 and the entire end face on the outer periphery side of the lid part 330. In this case, the entire end face 110T of the opening edge part 110 before welding in FIG. 7 and the entire end face 330T of the lid part 330 before welding in FIG. 7 disappear due to the formation of the alloy part 421, and the end faces of the opening edge part 110 and the lid part 330 that are not exposed to the outside are formed.

[0095] Alloy part 421 can be formed by, for example, melting the contact area between the end of opening edge 110 and the outer circumferential end of lid part 330 by laser welding. At this time, Ni contained in nickel layer 423 of the lid part diffuses to the opening edge part 110 side, and alloy part 421 containing Fe and Ni is formed. The Ni content in alloy part 421 is 1.4 mass % or more. However, since Ni diffuses from nickel layer 423 of the lid part to the opening edge part 110 side, the Ni concentration has a distribution in alloy part 421, and the Ni concentration may be higher on the lid part side than on the opening edge part side (cylinder part side).

[0096] In FIG. 7, the thickness of nickel layer 423 covering the end face of the lid portion needs to be 3 μm or more, and may be 7 μm or more, in order to form alloy portion 421 with an Ni content of 1.4 mass % or more.

[0097] In FIG. 6, nickel layer 422 covering outer surface S3 of lid 330 has nickel layer 422A formed in a region (first region) adjacent to alloy part 421, and nickel layer 422B formed in a region (second region) adjacent to the first region and opposite alloy part 421. Nickel layer 422A is a remaining portion of nickel layer 423 in FIG. 7 after welding. When alloy part 421 is formed to have a cross section (e.g., a sector shape) including a circular arc from the contact region between opening edge part 110 and lid 330 as in FIG. 6, nickel layer 423 may remain on the lid part on the inner periphery side of alloy part 421. In this case, when viewed from outer surface S3 of the lid, nickel layer 422A, which is the remaining portion of nickel layer 423, may have a thickness greater than that of nickel layer 422B.

[0098] The dimension (maximum width) of alloy part 421 in the axial direction (vertical direction) of battery can 100 is preferably smaller than the dimension (maximum width) of alloy part 421 in the radial direction (thickness direction of the cylindrical part) of the battery can. This configuration makes it easier to increase the proportion of nickel layer 423 in the molten part. This makes it easier to increase the nickel concentration in alloy part 421.

[0099] Alloy part 421 does not have to be formed on the entire outer peripheral end surface 330T of lid part 330, and only a portion of end surface 330T may be covered with nickel layer 423.

[0100] The outer peripheral end of the lid is bent outward (upward) in the axial direction of the cylindrical portion to form a protruding wall 332 that protrudes outward (upward). An alloy part 421 is formed at the tip of the protruding wall 332. Other configurations of the battery 11 are similar to those of the battery 10 in the first embodiment.

[0101] In this embodiment, the thickness of nickel layer 423 covering the end face of lid portion 330 is made thicker than nickel layer 422 covering the outer and inner surfaces of lid portion 330. However, the present invention is not limited to this. For example, when this embodiment is applied to the configuration of opening edge portion 110 and lid portion 330 shown in FIG. 2E, the nickel layer covering the inner surface of second portion 412 of lid portion 330 may be formed thicker than the nickel layer covering the end face of lid portion 330.

[0102] The method of this embodiment can also be applied to the battery according to the first embodiment. For example, in the case of the configuration of the opening edge portion 110 and the lid portion 330 shown in Figs. 1 to 3, the nickel layer covering the second surface S2 of the lid portion may be formed thicker than other portions. That is, in the second engagement portion 402 of the lid portion 330, the nickel layer at the interface that abuts against the opening edge portion 110 and in the vicinity thereof may be formed thicker than other portions. Also, the nickel layer at the welded portion forming surface of the second engagement portion 402 of the lid portion 330 and in the vicinity thereof may be formed thicker than other portions.

[0103] The material of the battery can 100 is not particularly limited, and examples thereof include iron and / or iron alloys (including stainless steel), copper, aluminum, aluminum alloys (including alloys containing trace amounts of other metals such as manganese and copper), etc. The material of the lid portion 330 is also not particularly limited, and examples thereof include the same material as that of the battery can 100.

[0104] The material of gaskets 320 and 350 is not limited, but for example, materials that are easy to mold into a single piece include polypropylene (PP), polyphenylene sulfide (PPS), polyethylene (PE), polybutylene terephthalate (PBT), perfluoroalkoxyalkane (PFA), polytetrafluoroethylene (PTFE), and polyamide (PA).

[0105] Next, the configuration of the electrode body 200 will be exemplarily described using a lithium ion secondary battery as an example. The cylindrical electrode body 200 is a wound type, and is configured by winding a positive electrode and a negative electrode in a spiral shape with a separator interposed therebetween. An internal lead wire 210 is connected to one of the positive electrode and the negative electrode. The internal lead wire 210 is connected to the inner surface of the central region 312 of the terminal portion 310 by welding or the like. Another lead wire is connected to the other of the positive electrode and the negative electrode, and the other lead wire is connected to the inner surface of the battery can 100 by welding or the like. In addition, another insulating plate (lower insulating plate) may be provided between the bottom 130 of the battery can 100 and the electrode body 200. In this case, the other lead wire may extend around the other insulating plate, or may be inserted into a through hole formed in the other insulating plate.

[0106] (Negative electrode) The negative electrode has a strip-shaped negative electrode collector and a negative electrode active material layer formed on both sides of the negative electrode collector. A metal film, a metal foil, or the like is used for the negative electrode collector. The material of the negative electrode collector is preferably at least one selected from the group consisting of copper, nickel, titanium, alloys thereof, and stainless steel. The thickness of the negative electrode collector is preferably, for example, 5 to 30 μm.

[0107] The negative electrode active material layer contains a negative electrode active material, and optionally contains a binder and a conductive agent. The negative electrode active material layer may be a deposition film formed by a gas phase method (e.g., vapor deposition). Examples of the negative electrode active material include Li metal, metals or alloys that react electrochemically with Li, carbon materials (e.g., graphite), silicon alloys, silicon oxides, and metal oxides (e.g., lithium titanate). The thickness of the negative electrode active material layer is preferably, for example, 1 to 300 μm.

[0108] (positive electrode) The positive electrode has a strip-shaped positive electrode current collector and a positive electrode active material layer formed on both sides of the positive electrode current collector. The positive electrode current collector may be a metal film, a metal foil (stainless steel foil, aluminum foil, or aluminum alloy foil), or the like.

[0109] The positive electrode active material layer contains a positive electrode active material and a binder, and optionally contains a conductive agent. The positive electrode active material is not particularly limited, but may be a lithium-containing composite oxide such as LiCoO2 or LiNiO2. The thickness of the positive electrode active material layer is preferably, for example, 1 to 300 μm.

[0110] The conductive agent contained in each active material layer is, for example, 0 to 20 parts by mass of the conductive agent per 100 parts by mass of the active material. The binder contained in the active material layer is, for example, fluororesin, acrylic resin, rubber particles, etc. The amount of the binder is, for example, 0.5 to 15 parts by mass of the binder per 100 parts by mass of the active material.

[0111] (Separator) As the separator, a resin microporous film or nonwoven fabric is preferably used. As the material (resin) of the separator, polyolefin, polyamide, polyamideimide, etc. are preferable. The thickness of the separator is, for example, 8 to 30 μm.

[0112] (electrolyte) The electrolyte may be a non-aqueous solvent in which a lithium salt is dissolved. Examples of the lithium salt include LiClO4, LiBF4, LiPF6, LiCF3SO3, LiCF3CO2, and imide salts. Examples of the non-aqueous solvent include cyclic carbonates such as propylene carbonate, ethylene carbonate, and butylene carbonate, chain carbonates such as diethyl carbonate, ethyl methyl carbonate, and dimethyl carbonate, and cyclic carboxylates such as γ-butyrolactone and γ-valerolactone.

[0113] Although a lithium ion secondary battery has been described as an example above, the present invention can be used in batteries in which the battery can is sealed using a sealing member, regardless of whether the battery is a primary battery or a secondary battery. [Industrial Applicability]

[0114] The battery according to the present invention can be used in various can-type batteries, and is suitable for use as a power source for portable devices, hybrid vehicles, electric vehicles, etc. Although the present invention has been described with respect to the presently preferred embodiments, such disclosure should not be interpreted as limiting. Various variations and modifications will no doubt become apparent to those skilled in the art to which the present invention pertains upon reading the above disclosure. Accordingly, the appended claims should be interpreted to cover all variations and modifications without departing from the true spirit and scope of the present invention. [Explanation of symbols]

[0115] 10, 11:Battery 100: Battery can 120:Cylinder part 110: Opening edge 110T: End face 150: Storage unit 130: Bottom 200: Electrode body 210: Internal lead wire 300: Sealing material 310:Terminal section 311: Periphery 312: Central area 313: Thin section 320: Gasket 321: Outer ring part 322: Inner ring part 323: Relay Ring Section 330: Lid 330T: End face 331: Top plate part 332:Protruding wall 334: Support part 350: Second gasket 401: First engagement part 402: Second engagement portion 411: Part 1 412:Second part 413: Third part 414: 4th part 415: 5th part 420: Joint 421: Alloy section 422, 422A, 422B: Nickel layer (second nickel layer) 423: Nickel layer (first nickel layer) 424: Nickel layer formed on the surface of the opening edge 425: Base metal layer 501: First external lead 502: Second external lead

Claims

1. a battery can having a cylindrical portion having an opening edge portion at one end and a bottom portion closing the other end of the cylindrical portion, an electrode body accommodated in the cylindrical portion, and a sealing member fixed to the cylindrical portion so as to seal an opening of the opening edge portion, The sealing member includes a lid portion that covers the opening, a first engagement portion is formed at the end portion of the cylindrical portion on the opening edge portion side; A second engagement portion is formed at an end portion on an outer circumferential side of the lid portion, a first surface of the first engagement portion and a second surface of the second engagement portion are joined in an overlapping state, the opening edge portion has a first portion that is bent and extends toward the outside or the inside of the cylindrical portion in a radial direction perpendicular to an axial direction of the cylindrical portion, The first portion forms the first engagement portion, The battery, wherein the first surface and the second surface are inclined obliquely with respect to the radial direction and the axial direction.

2. an outer peripheral end of the lid portion has a second portion that is bent and extends toward the bottom portion or the opening edge portion in the axial direction of the cylindrical portion, The battery of claim 1 , wherein the second portion forms the second engagement portion.

3. a battery can having a cylindrical portion having an opening edge portion at one end and a bottom portion closing the other end of the cylindrical portion, an electrode body accommodated in the cylindrical portion, and a sealing member fixed to the cylindrical portion so as to seal an opening of the opening edge portion, the sealing member includes a lid portion that covers the opening, a first engagement portion is formed at the end portion of the cylindrical portion on the opening edge portion side; A second engagement portion is formed at an end portion on an outer circumferential side of the lid portion, a first surface of the first engagement portion and a second surface of the second engagement portion are joined in an overlapping state, an outer peripheral end of the lid portion has a second portion that is bent and extends toward the bottom portion or the opening edge portion in the axial direction of the cylindrical portion, the second portion forms the second engagement portion; A battery, wherein the first surface and the second surface are inclined obliquely with respect to the axial direction and a radial direction perpendicular to the axial direction.

4. an outer peripheral end of the lid portion has a third portion bending and extending toward the bottom portion side or the opening edge portion side in the axial direction of the cylindrical portion, and a fourth portion bending and extending from the third portion in a direction opposite to the bending direction of the third portion, The battery of claim 1 , wherein the fourth portion forms the second engagement portion.

5. a battery can having a cylindrical portion having an opening edge portion at one end and a bottom portion closing the other end of the cylindrical portion, an electrode body accommodated in the cylindrical portion, and a sealing member fixed to the cylindrical portion so as to seal an opening of the opening edge portion, the sealing member includes a lid portion that covers the opening, a first engagement portion is formed at the end portion of the cylindrical portion on the opening edge portion side; A second engagement portion is formed at an end portion on an outer circumferential side of the lid portion, a first surface of the first engagement portion and a second surface of the second engagement portion are joined in an overlapping state, an outer peripheral end of the lid portion has a third portion bending and extending toward the bottom portion side or the opening edge portion side in the axial direction of the cylindrical portion, and a fourth portion bending and extending from the third portion in a direction opposite to the bending direction of the third portion, The fourth portion forms the second engagement portion.

6. The battery according to claim 4 , wherein the third portion extends along an inner circumferential surface of the cylindrical portion.

7. 4. The battery according to claim 1, wherein the lid portion is provided with a rib that stands on a surface facing the electrode body and extends along an inner peripheral surface of the cylindrical portion.

8. The battery according to claim 5 or 6, wherein the first surface and the second surface are inclined obliquely with respect to the axial direction and a radial direction perpendicular to the axial direction.

9. 9. The battery according to claim 1, wherein the first surface is an outer circumferential surface, an inner circumferential surface, or an end surface of the cylindrical portion.

10. The battery according to claim 8 or 9, wherein the second surface is a surface on the bottom side of the lid, a surface on the opening edge side, or an end face.

11. The battery according to any one of claims 1 to 8, wherein an end face of the tubular portion is inclined from a plane perpendicular to the extension direction of the opening edge portion, the inclined surface forming the first surface, and / or an end face on the outer periphery of the lid portion is inclined from a plane perpendicular to the extension direction of the outer periphery of the end portion of the lid portion, the inclined surface forming the second surface.

12. The battery according to any one of claims 3 and 8 to 11, wherein one of the first surface and the second surface has an area exposed to the outside without overlapping with the other surface.

13. an end portion of the cylindrical portion on the opening edge side and an end portion of the lid portion on the outer periphery side are joined by an alloy portion, The battery according to any one of claims 1 to 12, wherein the alloy portion contains iron and nickel, and the content of nickel contained in the alloy portion is 1.4 mass% or more.

14. The battery according to claim 13 , wherein the entire end face of the opening edge portion is covered with the alloy portion.

15. The battery according to claim 13 or 14, wherein the entire outer peripheral end face of the lid portion is covered with the alloy portion, or a portion of the outer peripheral end face of the lid portion is covered with the alloy portion and the remainder of the outer peripheral end face of the lid portion is covered with a first nickel layer.

16. The battery according to any one of claims 13 to 15, wherein a main surface constituting an outer surface of the lid portion is covered with a second nickel layer.

17. a part of an outer peripheral end surface of the lid portion is covered with the first nickel layer; a main surface constituting an outer surface of the lid portion is covered with a second nickel layer; 16. The battery of claim 15, wherein the first nickel layer has a thickness greater than a thickness of the second nickel layer.

18. The second nickel layer is formed in a first region adjacent to the alloy portion and a second region adjacent to the first region and located on the opposite side to the alloy portion, 18. The battery of claim 16 or 17, wherein a thickness of the second nickel layer in the first region is greater than a thickness of the second nickel layer in the second region.

19. The battery according to any one of claims 13 to 18, wherein the alloy portion has a higher nickel concentration on the lid side than on the opening edge side.

20. An outer peripheral end of the cover portion is bent outward in the axial direction of the cylindrical portion, The battery according to any one of claims 13 to 19, wherein the alloy portion is formed at a tip of a protruding wall that is bent outwardly.

21. The battery of any one of claims 13 to 20, wherein the tube portion comprises iron or an alloy thereof.

22. The battery according to any one of claims 13 to 21, wherein a dimension of the alloy portion in an axial direction of the battery can is smaller than a dimension of the alloy portion in a radial direction of the battery can.

23. The sealing member further has a terminal portion, The battery according to any one of claims 1 to 22, wherein the lid portion has a through hole, and the terminal portion blocks the through hole while being insulated from the lid portion.

24. The electrode body has a first electrode and a second electrode, the first electrode is electrically connected to the terminal portion, The second electrode is electrically connected to the battery can.

24. The battery of claim 23.

25. providing a battery can having a tubular portion with an open edge at one end and a bottom portion closing the other end of the tubular portion; preparing a sealing member having a lid portion for covering the opening of the opening edge portion; a welding step of welding the sealing member to the battery can, the opening edge portion of the battery can is bent, and a first surface is formed on the opening edge portion, the first surface being inclined obliquely with respect to a radial direction of the cylindrical portion; The cover portion has a second surface inclined obliquely with respect to the axial direction of the cylindrical portion at an end portion on an outer circumferential side of the cover portion, the welding process is a process of placing the sealing material on the battery can containing an electrode body so as to close the opening edge portion, and overlapping the first surface of the cylindrical portion against the second surface of the lid portion while pressing them together, thereby joining them by welding.

26. In the step of preparing the battery can, a battery can is prepared in which a nickel layer is formed on a side peripheral surface of the cylindrical portion and a surface of the bottom, and a nickel layer is not formed on an end surface of the opening edge portion; A nickel layer is formed on at least the outer peripheral end surface of the metal lid portion, The thickness of the nickel layer is 3 μm or more, The method for manufacturing a battery according to claim 25 , wherein in the welding step, an alloy portion is formed by melting the end of the lid portion on which the nickel layer is formed and an end of the opening edge portion which does not contain nickel.

27. the cylindrical portion includes iron or an alloy thereof; The method for producing a battery according to claim 26 , wherein in the step of preparing the battery can, an iron layer or an iron alloy layer is exposed on an end face of the opening edge portion.

28. The method for manufacturing a battery according to claim 26 or 27, wherein the alloy portion is formed on the entire end face of the opening edge portion in the welding step.

29. The sealing member further has a terminal portion, The method for manufacturing a battery according to any one of claims 25 to 28, wherein the lid portion has a through hole, and the terminal portion closes the through hole while being insulated from the lid portion.

Images