Button cell battery with terminal

Abstract

This terminal-equipped button cell has a cathode can and an anode can that are flat cylinders, a gasket that insulates and seals the cathode can and the anode can, and a positive terminal and a negative terminal that are fixed to the bottom surfaces of the cathode can and the anode can, respectively, and is characterized in that: when integrated with the anode can, the bottom surface of the cathode can is curved in a convex shape no more than 100 µm outward in the thickness direction; the positive terminal has a flat positive connecting part; the positive terminal is disposed along the radial direction of the bottom surface of the cathode can; and the positive connecting part is inclined such that, in a cross-sectional view following the radial direction and perpendicular to the bottom surface, the positive connecting part forms a tangent line to the bottom surface at a position other than the center of the bottom surface and is fixed to the bottom surface.

Description

[Technical field]

[0001] The present invention relates to a terminal-equipped button battery. This application claims priority based on Japanese Patent Application No. 2021-042785 filed on March 16, 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] Coin- or button-type flat silver oxide batteries are used in small electronic devices. These silver oxide batteries have the advantage of maintaining stable voltage for a long period of time by using silver oxide as the positive electrode active material (see Patent Document 1). When a coin-type battery is used in a small electronic device, it may be required to attach it to a printed circuit board. For example, for lithium batteries such as lithium secondary batteries and CR primary batteries, a widely known technique is to weld lead terminals made of nickel plates or the like to the battery and then solder them to the board (see Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-44906 A [Patent Document 2] Japanese Utility Model Application Publication No. 62-157060 Summary of the Invention [Problem to be solved by the invention]

[0004] In the silver oxide battery described in Patent Document 1, a positive electrode mixture (a mixture of active material, conductive additive, binder, etc.) is placed inside the bottom surface of a positive electrode can. After a separator, a gasket, an electrolyte, and a negative electrode mixture are assembled into the positive electrode can, the negative electrode can is placed on top of the can and placed on an assembly machine, and the positive electrode can is crimped against the periphery of the negative electrode can to produce a silver oxide battery. Here, depending on the combination of the crimping shape, the filling rate of the active material and electrolyte relative to the internal volume, and the materials of the positive and negative electrode cans, stress is generated at the bottom of the positive can during crimping, and the positive can expands slightly in the thickness direction, with the maximum near the center relative to the circumferential side of the positive can.

[0005] In particular, in alkaline primary batteries including the above-mentioned silver oxide battery, in order to obtain the largest possible discharge capacity, the positive electrode can is strongly crimped during assembly to prevent leakage of the electrolyte while increasing the filling rate of the active material and electrolyte. At this time, stress is likely to be generated in the positive electrode can, and expansion tends to occur near the center of the positive electrode can. In addition, in non-aqueous button type primary batteries and button type secondary batteries, the positive electrode can may expand like an alkaline primary battery, depending on the balance of factors such as the filling rate of the active material and electrolyte, the materials of the positive electrode can and the negative electrode can, and the stress during crimping.

[0006] The terminals to be welded to coin or button type batteries come in various shapes for attachment to the circuit board of the installed device or other objects, but typically the flat part of the battery (the bottom surface of the positive or negative can) is welded to the flat part of the terminal. Here, when a terminal is welded to a positive electrode can with an expanded center as described above, when the terminal is placed across the center of the positive electrode can, the positive electrode can and the terminal come into contact on one side of the terminal, with the center of the positive electrode can as the boundary, but a gap will be created between the positive electrode can and the terminal on the other side of the terminal. Then, for example, when attempting to weld a terminal to a battery can at multiple welds, the above-mentioned gaps may have an effect, resulting in insufficient welding in some places and reduced weld strength.

[0007] An object of the present invention is to provide a terminal-equipped button battery having a configuration in which a battery can and a terminal are stably joined. [Means for solving the problem]

[0008] (1) The terminal-equipped button battery of the present invention is a terminal-equipped button battery having flattened cylindrical positive and negative cans, gaskets for insulating and sealing the positive and negative cans, and positive and negative terminals fixed to the bottom surfaces of the positive and negative cans, respectively, wherein the bottom surface of the positive can is curved outwardly in a thickness direction by 100 μm or less when integrated with the negative can, the positive terminal has a flat positive connection portion, the positive electrode terminal has a positive electrode connection part which is connected to the positive electrode can by welding, an intermediate part which bends from the positive electrode connection part and extends toward the negative electrode can, and a substrate connection part which bends further from the intermediate part, extends in a direction away from the positive electrode can, and is connectable to a substrate; The positive electrode terminal is disposed along the radial direction of the bottom surface of the positive electrode can, and the positive electrode connection portion is configured to be inclined so as to form a tangent to the bottom surface at a position other than the center of the bottom surface and to be fixed to the bottom surface in a cross-sectional view passing through the radial direction and perpendicular to the bottom surface. (2) The terminal-equipped button battery according to the present invention is A terminal-equipped button battery comprising: a flat cylindrical positive electrode can and a negative electrode can, a gasket for insulating and sealing the positive electrode can and the negative electrode can, and a positive electrode terminal and a negative electrode terminal fixed to the bottom surface of the positive electrode can and the negative electrode can, respectively, wherein the bottom surface of the positive electrode can is curved outwardly in a thickness direction by 100 μm or less when integrated with the negative electrode can, the positive electrode terminal has a flat positive electrode connection portion, and the positive electrode terminal has a positive electrode connection portion that is connected to the positive electrode can by welding. a negative electrode can side, a connecting portion, an intermediate portion bent at approximately a right angle from the positive electrode connection portion and extending toward the negative electrode can side, and a substrate connection portion bent again at approximately a right angle from the intermediate portion, extending in a direction away from the positive electrode can and connectable to a substrate, the positive electrode terminal is disposed along the radial direction of the bottom surface of the positive electrode can, and the positive electrode connection portion is inclined so as to form a tangent to the bottom surface at a position other than the center of the bottom surface in a cross-sectional view passing through the radial direction and perpendicular to the bottom surface, and is fixed to the bottom surface.

[0009] In the above-mentioned terminal-equipped button battery, the positive electrode connection part of the positive electrode terminal is fixed along a tangent line at a fixed position on the bottom of the positive electrode can, so that the positive electrode connection part can be connected to the bottom of the positive electrode can without any gaps. By connecting the positive electrode connection part in this manner, the positive electrode terminal can be reliably fixed in close contact with the bottom of the positive electrode can even if the bottom of the positive electrode can bulges by about 100 μm or less. By having an intermediate portion that is bent at a substantially right angle from the positive electrode connection portion and a board connection portion that is bent again at a substantially right angle from the intermediate portion, when the battery is attached to a connection surface such as a terminal pad of a board, the board connection portion can be attached at a desired angle to the connection surface of the board. If the positive electrode terminal is inclined along the curvature of the bottom surface of the positive electrode can and the board connection portion is inclined at a small angle to the connection surface, the small gap that occurs between the board connection portion and the connection surface can be effectively used as a solder pool. This makes it possible to provide a button battery with terminals that has excellent bonding properties when soldered. (3) In the terminal-equipped button battery according to the present invention described in (2), it is preferable that the board connection portion is inclined with respect to a connection surface of the board to which the board connection portion is connected. (4) In the terminal-equipped button battery according to any one of (1) to (3) of the present invention, it is preferable that the battery further comprises a flat negative terminal having a substrate connection portion connected to the negative can and extending substantially flush with the substrate connection portion of the positive terminal. (5) A terminal-equipped button battery according to the present invention is a terminal-equipped button battery having flattened cylindrical positive and negative cans, gaskets that insulate and seal the positive and negative cans, and a positive terminal and a negative terminal fixed to the bottom surfaces of the positive and negative cans, respectively, wherein the bottom surface of the positive can is curved convexly outward in the thickness direction by 100 μm or less when integrated with the negative can, the positive terminal has a flat positive connection portion, the positive terminal is disposed along the radial direction of the bottom surface of the positive can, the positive connection portion is inclined so as to form a tangent to the bottom surface at a position other than the center of the bottom surface in a cross-sectional view passing through the radial direction and perpendicular to the bottom surface, and is fixed to the bottom surface, and further comprises a flat negative terminal connected to the negative can and equipped with a substrate connection portion that extends approximately flush with the substrate connection portion of the positive terminal.

[0010] ( 6 ) In a terminal-equipped button battery according to one embodiment of the present invention, it is preferable that the positive terminal is welded to the positive electrode can at a position between the center of the bottom surface of the positive electrode can and the peripheral edge of the bottom surface of the positive electrode can with multiple welds.

[0011] The bottom surface of the positive electrode can is curved convexly outward, and the positive electrode terminal is arranged along the curved bottom surface. By providing multiple welds between the center of the bottom surface of the positive electrode can and the peripheral edge of the bottom surface of the positive electrode can, the positive electrode terminal can be securely fixed to the bottom surface of the positive electrode can.

[0012] ( 7In the terminal-equipped button battery according to one embodiment of the present invention, the positive electrode terminal may have a thickness of 0.07 to 0.15 mm.

[0013] If the thickness of the positive terminal is 0.07 to 0.15 mm, the strength of the terminal can be ensured. In addition, when the positive terminal is fixed to the positive can by welding, the welding machine can apply an appropriate amount of heat. If the thickness of the positive terminal is thinner than the above range, the positive terminal may break and be partially damaged during welding, and the weld strength may not be improved.

[0017] When connecting the board connection part to the board, the board connection part can be soldered in a state where it is slightly inclined with respect to the joining surface of the board. When the board connection part is slightly inclined with respect to the joining surface of the board, a minute gap can be generated between the joining surface of the board and the board connection part. When soldering is performed in a portion with this gap, the solder can be caused to penetrate into the gap and soldering can be performed while generating a solder pool. Therefore, it is possible to provide a button battery with terminals that can provide a highly reliable joining structure by soldering.

[0019] By having a negative terminal in addition to a positive terminal, the battery can be attached by connecting the board connection part of the positive terminal and the board connection part of the negative terminal to the board. Also, by providing a flat negative terminal that is almost flush with the board connection part of the positive terminal, the size in the thickness direction of the terminal-equipped button battery can be minimized. (8) A terminal-equipped button battery according to one embodiment of the present invention includes a flat cylindrical positive electrode can and a negative electrode can, a gasket that insulates and seals the positive electrode can and the negative electrode can, and a positive electrode terminal and a negative electrode terminal fixed to bottom surfaces of the positive electrode can and the negative electrode can, respectively, wherein the bottom surface of the positive electrode can is curved convexly outwardly in a thickness direction by 100 μm or less when integrated with the negative electrode can, the positive electrode terminal has a flat positive electrode connection portion, and the positive electrode terminal is disposed along a radial direction of the bottom surface of the positive electrode can, the positive electrode connection portion is inclined so as to form a tangent to the bottom surface at a position other than the center of the bottom surface in a cross-sectional view passing through the radial direction and perpendicular to the bottom surface, and the positive electrode terminal is fixed to the bottom surface. the negative electrode terminal has a plate-shaped negative electrode connection portion that is arranged along the surface of the negative electrode can and a substrate connection portion that extends the negative electrode connection portion flush with the surface of the negative electrode can in a direction away from the negative electrode can, and the positive electrode terminal can has a configuration in which the substrate connection portion of the positive electrode terminal is inclined so that the bent portion between the intermediate portion of the positive electrode terminal and the substrate connection portion is located above the tip side of the substrate connection portion in a cross-sectional view passing through the radial direction and perpendicular to the bottom surface, with the positive electrode connection portion on top and the negative electrode connection portion on the bottom. Effect of the Invention

[0020] In the terminal-equipped button battery according to the present invention, the positive electrode connection part of the positive electrode terminal is fixed along a tangent line at a fixed position on the bottom surface of the positive electrode can, so that the positive electrode connection part can be connected to the bottom surface of the positive electrode can without any gaps. By connecting the positive electrode connection part in this manner, it is possible to provide a structure in which the positive electrode terminal is reliably fixed along the bottom surface of the positive electrode can even if the bottom surface of the positive electrode can bulges by about 100 μm or less. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a perspective view showing a terminal-equipped button battery according to a first embodiment. [Diagram 2] FIG. 2 is a plan view of the terminal-equipped button battery. [Figure 3A] FIG. 2 is a side view of the terminal-equipped button battery. [Figure 3B] FIG. 2 is a partially enlarged view of the terminal-equipped button battery. [Figure 4] FIG. 2 is a cross-sectional view of a battery 1 constituting the terminal-equipped button battery. [Diagram 5] 4 is an explanatory diagram showing a desirable welding range of the terminal to the battery can of the terminal-equipped button battery. FIG. [Figure 6] FIG. 6 is a plan view showing a terminal-equipped button battery according to a second embodiment. [Figure 7] FIG. 11 is a plan view showing a terminal-equipped button battery according to a third embodiment. [Figure 8] FIG. 13 is a plan view showing a terminal-equipped button battery according to a fourth embodiment. [Figure 9] FIG. 2 is an explanatory diagram of a welding strength test performed on the terminal-equipped button battery manufactured in the examples. [Figure 10] 1 is a graph showing the relationship between welding strength and heat quantity in an example and a comparative example. [Figure 11] 1 is a graph showing the relationship between weld depth and weld strength in an example and a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of a terminal-equipped button battery according to the present invention will be described with reference to the drawings. In the drawings used in the following description, the scale of each component may be appropriately changed in order to make each component recognizable.

[0023] First Embodiment 1 to 4 are diagrams showing a terminal-equipped button battery according to a first embodiment of the present invention. Battery 1 of this embodiment is a battery in which a positive electrode mixture, a negative electrode mixture, an electrolyte, and the like described below are housed in a flat metal can. The metal can has a positive electrode can 2 and a negative electrode can 3. A positive electrode terminal 10 and a negative electrode terminal 11 are attached to the positive electrode can 2 and the negative electrode can 3 so as to sandwich them from both sides in the thickness direction, and these are attached to the positive electrode can 2 or the negative electrode can 3 by welding. As a result, the terminal-equipped button battery 100 of this embodiment has a structure in which the positive electrode terminal 10 and the negative electrode terminal 11 are attached to the battery 1.

[0024] An outline of the internal structure of the battery 1 is shown in FIG. 4. The positive electrode can 2 is made of, for example, stainless steel (SUS) plated with nickel, and is molded into a flat cylindrical shape (shallow cup shape). This positive electrode can 2 contains a positive electrode mixture 5 and functions as a positive electrode current collector. The negative electrode can 3 is made of, for example, a clad material with a three-layer structure having an outer surface layer made of nickel, a metal layer made of stainless steel (SUS), and a current collector layer made of copper, and is molded into a flat cylindrical shape (shallow cup shape). The negative electrode can 3 has a circular opening 3a that is folded back, and a ring-shaped gasket 4 made of, for example, nylon is attached to the opening 3a.

[0025] The negative electrode can 3 is fitted into the circular opening 2f of the positive electrode can 2 from the opening 3a side where the gasket 4 is attached, and the opening 2f of the positive electrode can 2 is crimped toward the gasket 4 to seal, thereby forming a disk-shaped (button-shaped or coin-shaped) case 8. An airtight space 8S is formed inside the case 8. The gasket 4 insulates and seals the positive electrode can 2 and the negative electrode can 3. A positive electrode mixture 5, a separator 6, and a negative electrode mixture 7 are accommodated in the sealed space 8S, with the positive electrode mixture 5 being disposed on the positive electrode can 2 side and the negative electrode mixture 7 being disposed on the negative electrode can 3 side with the separator 6 interposed therebetween.

[0026] When assembling this battery 1, the positive electrode mixture 5 formed into pellets is filled into the positive electrode can 2. Also, a separator 6 is laid on top of the positive electrode mixture 5, and a gasket 4 is press-fitted into the positive electrode can 2. Then, a gel-like negative electrode mixture 7 is placed on the separator 6, and the negative electrode can 3 is placed over it. Further, the opening edge of the positive electrode can 2 is caulked to seal the case 8. The sealed state, for example, the difference (H2 - H1) between the height position (H1) of the opening of the positive electrode can 2 and the height position (H2) of the bottom of the negative electrode can 3 is, for example, 0.10 to 0.15 mm in a silver oxide battery of the SR716SW (outer diameter 7.9 mm, height 1.6 mm) type. Also, it is defined as follows in the IEC (International Electrotechnical Commission) standard. When H2 ≤ 1.65, it is 0.02 mm or more; when 1.65 < H2 < 2.5, it is 0.06 mm or more; when H2 ≥ 2.5, it is 0.08 mm or more.

[0027] The positive electrode mixture 5 contains a positive electrode active material, a conductive agent, an electrolyte, a binder, an additive, etc. The positive electrode active material is not particularly limited as long as it can be used as a positive electrode active material when zinc or a zinc alloy is used as the negative electrode active material. For example, the positive electrode active material may be silver oxide or manganese dioxide powder or a mixture thereof. Or, the positive electrode active material may be nickel oxyhydroxide alone or nickel oxyhydroxide in which cobalt or the like is solid-solved. As the conductive aid, graphite or the like can be used. As the additive, a hydrogen storage alloy (LaNi5) or the like can be used.

[0028] The negative electrode mixture 7 contains, for example, a negative electrode active material, a conductivity stabilizer, a gelling agent, an electrolyte, a viscoelasticity modifier, an additive (thickener, resin powder), etc. As the negative electrode active material, for example, zinc powder or zinc alloy powder can be used. As the conductivity stabilizer, zinc oxide (ZnO) or the like can be used. Also, as the gelling agent, carboxymethyl cellulose, or polyacrylic acid, or a mixture of carboxymethyl cellulose and polyacrylic acid is preferable. By using carboxymethyl cellulose or polyacrylic acid, the lyophilicity and liquid retention of the negative electrode mixture 7 with respect to the electrolyte can be improved.

[0029] The electrolyte may be an aqueous solution of potassium hydroxide, an aqueous solution of sodium hydroxide, or a mixture thereof. The viscoelasticity adjusting material is blended to adjust the viscoelasticity of the negative electrode mixture 7 to a viscoelasticity that provides good handling properties and improves productivity. As the viscoelasticity adjusting material, a resin powder that does not react with the strongly alkaline electrolyte is used. Here, the state of not reacting with the electrolyte means a state in which the material does not chemically react with the electrolyte and does not absorb the electrolyte.

[0030] The separator 6 is interposed between the positive electrode mixture 5 and the negative electrode mixture 7, and is made of an insulating film having high ion permeability and mechanical strength. As the separator 6, any separator conventionally used for a battery separator can be used without any limitation, for example, a microporous membrane such as a polyethylene film, cellophane, or a graft polymerization membrane, or a nonwoven fabric such as liquid-absorbent paper made of cellulose can be used. Furthermore, these microporous membranes and nonwoven fabrics may be used in combination.

[0031] In the battery 1 shown in Figs. 1 to 4, the opening edge of the positive electrode can 2 is crimped to be integrated with the negative electrode can 3 to form a case 8, as described above. Since the inside of the case 8 is filled with as much positive electrode mixture 5, negative electrode mixture 7, and electrolyte as possible, the bottom surface (outer surface) 2A of the positive electrode can 2 may be curved due to the crimping stress after the positive electrode can 2 is crimped, so that the bottom center 2a of the positive electrode can 2 bulges outward in a convex shape. When the bottom surface 2A of the positive electrode can 2 is curved, the amount of bulging (curve height) at the bottom center (outer surface center) 2a is 100 µm or less compared to when it is not curved.

[0032] In this embodiment, the positive electrode terminal 10 is joined to the slightly curved bottom surface 2A by laser welding. The positive electrode terminal 10 is made of a plate material of a metal material having good electrical conductivity such as stainless steel (SUS). The thickness of the plate material constituting the positive electrode terminal 10 is preferably 0.07 mm or more and 0.15 mm or less. If the thickness of the positive electrode terminal 10 is 0.07 to 0.15 mm, the strength of the terminal can be ensured. In addition, when the positive electrode terminal 10 is fixed to the positive electrode can 2 by welding, the welding machine can apply an appropriate amount of heat. If the thickness of the positive electrode terminal 10 is thinner than the above range, the positive electrode terminal may break and be partially damaged during welding, and the weld strength may not be improved. The positive electrode terminal 10 has a rectangular plate-like positive electrode connection portion 10A arranged along the bottom surface 2A of the positive electrode can 2, an intermediate portion 10B extending at a substantially right angle to the positive electrode connection portion 10A, and a flat board connection portion 10C extending at a substantially right angle to the intermediate portion 10B. The intermediate portion 10B has a tapered shape, and the board connection portion 10C extends from the intermediate portion 10B, having a width that is about 1 / 4 of the width of the positive electrode connection portion 10A. The board connection portion 10C is a portion that is soldered to a connection surface S (see FIG. 3) of a terminal pad or the like that is formed on the board on which the battery 1 of this embodiment is mounted. Therefore, the board connection portion 10C is a connection portion that can be connected to the board.

[0033] The negative electrode terminal 11 has a rectangular plate-shaped negative electrode connection part 11A arranged along the surface of the negative electrode can 3 and a board connection part 11C extending from one end of the negative electrode connection part 11A. The board connection part 11C is formed so as to extend the plate-shaped negative electrode connection part 11A flush with the surface. The board connection part 11C is a part that is soldered to a connection surface S such as a terminal pad formed on a board on which the battery 1 of this embodiment is mounted, just like the board connection part 10C on the positive electrode side. The length and width of the board connection part 11C of the negative electrode terminal 11 are appropriately set according to the size of the terminal pad formed on the board on which the battery 1 of this embodiment is mounted. As an example, as shown in FIG. 1, the board connection part 11C is formed to have approximately the same length and width as the board connection part 10C of the positive electrode terminal 10. The board connection part 10C extends in a direction away from the positive electrode can 2. Negative electrode terminal 11 is welded to the bottom surface (outer surface) of negative electrode can 3 so that substrate connection portion 11C is adjacent to substrate connection portion 10C of positive electrode terminal 10. Negative electrode terminal 11 is generally flat and extends along the bottom surface of negative electrode can 3.

[0034] In the above-mentioned positive electrode terminal 10, the length of positive electrode connection part 10A is formed slightly shorter than the diameter of bottom surface 2A, and the length of intermediate part 10B is formed to a length equivalent to the thickness of case 8 consisting of positive electrode can 2 and negative electrode can 3. Therefore, when positive electrode connection part 10A is aligned with bottom surface (outer surface) 2A of positive electrode can 2, intermediate part 10B reaches from the bottom to the top of case 8 along the thickness direction of case 8, and substrate connection part 10C is positioned at a position approximately flush with the surface of negative electrode can 3.

[0035] In this embodiment, as shown in FIG. 1, the positive electrode connection portion 10A is positioned along the diameter (radial direction) of the bottom surface 2A of the positive electrode can 2, the middle portion 10B is spaced slightly outside the side surface of the case 8, and the substrate connection portion 10C is positioned so as to be approximately flush with the surface of the negative electrode can 3. In other words, the positive electrode terminal 10 is disposed so as to pass through the center 2a of the bottom surface 2A and the peripheral edge 2b on one side of the bottom surface 2A along the radial direction of the bottom surface 2A from the center 2a. The length of the positive electrode connection part 10A is longer than the radius of the bottom surface 2A and shorter than the diameter. Therefore, the tip part 10a of the positive electrode connection part 10A extends beyond the center 2a of the bottom surface 2A to the intermediate position between the center 2a and the peripheral edge 2d on the other side of the bottom surface 2A. The position of the tip 10a of the positive electrode connecting part 10A may be a position that does not exceed the center 2a. That is, although the position of the tip 10a is located to the left of the center 2a in Fig. 3, the position of the tip 10a may be located to the right of the center 2a. Therefore, the length of the positive electrode connecting part 10A may be formed to be shorter than the radius of the bottom surface 2A.

[0036] In this embodiment, a circular first welded portion 15 is formed in a portion of positive electrode connection portion 10A of positive electrode terminal 10 facing center 2a of the bottom surface of positive electrode can 2. In addition, two circular second welded portions 16 are formed in positive electrode connection portion 10A of positive electrode terminal 10 at positions close to peripheral edge 2b of the bottom surface of positive electrode can 2 and spaced apart in the width direction of positive electrode terminal 10. Both the first welded portion 15 and the second welded portion 16 are welded portions formed by laser welding. The maximum weld depth of the first welded portion 15 and the second welded portion 16 to the bottom wall of the positive electrode can is desirably 5 μm or more relative to the thickness of the bottom wall of the positive electrode can. The diameter of the first welded portion 15 and the second welded portion 16 is preferably in the range of 0.3 to 0.7 mm.

[0037] In this embodiment, the position where the first welded portion 15 is formed is desirably at or near the center 2a of the bottom surface 2A of the positive electrode can 2. The vicinity of the center 2a refers to the side closer to the imaginary line L in the hatched region E partitioned between the imaginary line L and the peripheral edge 2b of the bottom surface 2A when an imaginary line L is drawn passing through the center 2a along the width direction of the positive electrode connection part 10A as shown in Fig. 5 . In this embodiment, the second welded portion 16 is formed on the side closer to the peripheral edge 2b in an area E defined by oblique lines between the imaginary line L and the peripheral edge 2b of the bottom surface 2A, as shown in Fig. 5. Therefore, the second welded portion 16 is formed on the side closer to the peripheral edge 2b than the first welded portion 15. Therefore, the positive electrode connection part 10A is welded and fixed at a position of the second welded part 16 other than the center of the bottom surface 2A of the positive electrode can 2, along the bottom surface 2A of the positive electrode can 2 with an inclination of a tangent line t at this welding position. That is, the positive electrode connection part 10A is fixed to the bottom surface 2A at an inclination so as to form a tangent line t with the bottom surface 2A at a position other than the center of the bottom surface 2A in a cross-sectional view passing through the radial direction of the bottom surface 2A on which the positive electrode connection part 10A is arranged and perpendicular to the bottom surface 2A. The distance between center 2a of bottom surface 2A and second weld 16 varies depending on the outer diameter of positive electrode can 2, and can be selected from the range of about 1 mm to 5 mm for battery 1 with an outer diameter of about ψ4 mm to ψ12 mm.

[0038] A terminal-equipped button battery 100 having a positive electrode terminal 10 and a negative electrode terminal 11 is attached by soldering to a connection surface S of a terminal pad of a substrate or the like having an electric circuit. The terminal-equipped button battery 100 having a substrate connection portion 10C of the positive electrode terminal 10 and a substrate connection portion 11C of the negative electrode terminal 11 in the state shown in Fig. 1 is brought into contact with the terminal pad (connection surface) of the substrate and soldered, whereby the terminal-equipped button battery 100 can be mounted on the substrate.

[0039] In the terminal-equipped button battery 100 of this embodiment, the first welded portion 15 and the second welded portion 16 are formed at the above-mentioned positions, and further, the bottom surface 2A is bulged in a convex shape by 100 μm or less. Therefore, the positive electrode terminal 10 is attached to the positive electrode can 2 in a state where it is slightly inclined along the bottom surface 2A that forms a convex curved surface. If the bottom surface 2A were flat instead of convex, the middle portion 10B would be parallel to the central axis of the case 8, and the substrate connection portion 10C would be approximately flush with the surface of the negative electrode can 3.

[0040] In contrast, when the bottom surface 2A is inclined as described above, the positive electrode connection portion 10A, which is inclined to form the aforementioned tangent line t, is inclined so that the side closer to the peripheral edge 2b of the bottom surface 2A is closer to the negative electrode can 3 than the center 2a side. As shown in FIG. 3, the positive electrode connection part 10A is inclined along the tangent line t so that the right end side is lower than the left end side. Due to this inclination, as shown in an enlarged view in FIG. 3, the board connection part 10C is also inclined downward to the right. If the board connection part 10C is inclined downward to the right, when the board connection part 10C is brought into contact with a connection surface S such as a terminal pad on a board, the base end (middle part side) of the board connection part 10C rises slightly from the connection surface S to generate a minute gap G. Solder flows into this gap G during soldering, and becomes a solder pool. For this reason, a structure including the above-mentioned board connection part 10C is an advantageous structure during soldering.

[0041] In the terminal-equipped button battery 100 configured as described above, the positive electrode connection part 10A is disposed along the curved bottom surface 2A, the first welded part 15 is formed on the side closer to the center 2a in region E, and the second welded part 16 is provided on the side closer to the periphery 2b than the first welded part 15 in region E. Therefore, the first welded part 15 and the second welded part 16 can be disposed in the portion where the positive electrode connection part 10A is disposed along the bottom surface 2A or in the vicinity thereof. Therefore, the first welded part 15 and the second welded part 16 can be obtained as reliable welded parts by laser welding.

[0042] Furthermore, the terminal-equipped button battery 100 having the above-mentioned configuration is provided with a flat plate-shaped negative electrode terminal 11, so that the thickness of the terminal-equipped button battery 100 can be minimized. In addition, the terminal-equipped button battery 100 has the above-mentioned positive electrode terminal 10, and as described above, is inclined with a gap G with respect to the connection surface S of the substrate, making it possible to perform soldering using a solder pool, in which case the substrate connection portion 11C can be soldered by being closely arranged with no gap to the connection surface S of the substrate to be connected. Therefore, soldering can be performed without applying a load that would bend the substrate connection portion 11C of the negative electrode terminal 11 toward the positive electrode can 2. Furthermore, since soldering can be performed without applying a load to the negative electrode terminal 11, a short circuit with the positive electrode can 2 due to deformation of the negative electrode terminal 11 can be prevented.

[0043] 6 shows a terminal-equipped button battery according to a second embodiment of the present invention. The terminal-equipped button battery 20 of the second embodiment is different from the terminal-equipped button battery 100 of the first embodiment in the positions and number of second welded portions 16 provided on the positive electrode connecting portion 10A of the positive electrode terminal 10. The difference is that in the positive electrode connection portion 10A of the positive electrode terminal 10, one circular second welded portion 16 is formed in a position close to the peripheral edge 2b of the bottom surface 2A of the positive electrode can 2, in the center of the positive electrode terminal 10 in the width direction.

[0044] In the structure of the first embodiment, two second welded portions 16 are provided on the bottom surface 2A near the peripheral edge 2b, whereas in the structure of the second embodiment, one second welded portion 16 is provided near the peripheral edge 2b. As in the second embodiment shown in FIG. 6, the number of second welded parts 16 may be one. The terminal-equipped button battery 20 of the second embodiment can also provide the same effects as the terminal-equipped button battery 1 of the first embodiment.

[0045] FIG. 7 shows a terminal-equipped button battery of a third embodiment according to the present invention. The terminal-equipped button battery 25 of the third embodiment is characterized in that a third welding portion 26 is provided compared to the terminal-equipped button battery 20 of the second embodiment.

[0046] A terminal-equipped button battery 25 of the third embodiment is different from the previous second embodiment in that a third welded portion 26 is provided between the first welded portion 15 and the second welded portion 16 provided therein. The terminal-equipped button battery 25 of the third embodiment can also provide the same effects as the terminal-equipped button battery 100 of the first embodiment.

[0047] FIG. 8 shows a terminal-equipped button battery of the fourth embodiment according to the present invention. The terminal-equipped button battery 30 of the fourth embodiment is characterized in that, compared to the terminal-equipped button battery 100 of the first embodiment, it has two first welds 15 and also two second welds 16. In the structure of the fourth embodiment, when an imaginary line L is drawn passing through the center 2a along the width direction of the positive electrode connection part 10A as shown in Fig. 8, two first welded parts 15 are formed at a distance from each other at positions along the imaginary line L. Two second welded parts 16 are also formed at positions close to the peripheral edge 2b so as to be aligned in parallel with the two first welded parts 15. In the fourth embodiment, two first welded parts 15 and two second welded parts 16 are provided, but there is no particular limit to the number of each type of welded part provided. The terminal-equipped button battery 30 of the fourth embodiment can also provide the same effects as the terminal-equipped button battery 100 of the first embodiment. EXAMPLES

[0048] A prototype button-type silver oxide battery with an outer diameter of 7.9 mm and a thickness of 1.65 mm and the internal structure shown in Figure 4 was fabricated and subjected to testing. Both the positive and negative electrode cans of this button-type battery were made of stainless steel, and the thicknesses of the stainless steel constituting the inner and bottom walls of the positive and negative electrode cans were 0.15 mm and 0.23 mm, respectively. As shown in Figure 4, a positive electrode mixture, a separator, a negative electrode mixture, and an electrolyte were placed inside the positive electrode can and the negative electrode can, and a gasket was attached. The positive electrode can was then crimped to seal the opening, to fabricate a prototype battery. In addition, since the positive electrode mixture and the negative electrode mixture were filled into the sealed spaces of the positive electrode can and the negative electrode can, the crimping of the positive electrode can caused a convex curve of 100 μm or less at the center of the bottom surface of the positive electrode can. We fabricated several prototype batteries with the above structure. The convex curvature of the bottom surface of the positive electrode can differed depending on the battery, but in all cases it was within the range of 5μm to 70μm.

[0049] Positive electrode terminals with the shape shown in Figure 1 were attached to these prototype batteries by welding. The positive electrode terminals were made of stainless steel (SUS304), and four types of positive electrode terminals with thicknesses of 0.07 mm, 0.10 mm, 0.15 mm, and 0.20 mm were used as shown in Table 1 below. The length of the positive electrode connection part of the positive electrode terminal was 6 mm, and the width was 2 mm. As shown in Figure 1, three welding positions were used: one at the center of the bottom of the positive can, and two at positions 2 mm away from the bottom edge to the bottom center, spaced 1 mm apart in the plate width direction of the positive joint. Since the amount of heat that can be applied by the laser welding machine can be adjusted, welding was performed on the positive terminals of the four plate thicknesses mentioned above by setting the amount of heat applied by the laser welding machine to various values ​​in the range of 2.6 J to 6.0 J and the pulse width in the range of 2 to 4 msec, as shown in Table 2 below. In addition, the weld strength of the laser-welded positive terminals was measured according to the following method.

[0050] "Welding strength test" The weld strength test was performed by bending the tip of the board connection part 10C of the battery 1 in a direction perpendicular to the welding surface (bottom surface 2A) as shown in Figure 9. Next, the tip of this bent board connection part 10C was clamped in a jig, the battery 1 was pressed so as to avoid the terminal parts, and the board connection part 10C was pulled in the direction of the arrow F in Figure 9. After that, the force when the second weld part 16 peeled off from the bottom surface 2A was recorded with a force gauge and used as the weld strength. Table 2 below shows the terminal thickness (terminal thickness), the amount of heat during laser welding, and the obtained weld strength of the second weld.

[0051] [Table 1]

[0052] [Table 2]

[0053] The relationship between the amount of heat during welding and the terminal thickness shown in the measurement results in Table 2 is summarized in a graph shown in Figure 10, where the horizontal axis represents the amount of heat (J) and the vertical axis represents the welding strength (N). As shown in the graph in FIG. 10 and Table 2, if the lower limit of the weld strength is set to 10 N, it can be seen that for the three types of positive electrode terminals with thicknesses of 0.07 mm, 0.10 mm, and 0.15 mm, a sufficiently high weld strength can be obtained by welding them with a heat quantity of about 2.6 J to 4.5 J. For a positive terminal with a thickness of 0.20 mm, the heat quantity during welding must be increased to 6.0 J in order to obtain a satisfactory weld strength. Applying 6.0 J as the heat quantity during welding will unnecessarily heat the inside of the battery, and there are concerns that the heat may have a detrimental effect on the battery active material and electrolyte. In particular, in the case of silver oxide batteries, it is possible to obtain a good weld while preventing deterioration of the silver oxide. From the results shown in FIG. 10, it is considered that in order to ensure welding strength without applying too much heat, a terminal with a plate thickness in the range of 0.07 to 0.15 mm is preferable.

[0054] In addition, in the case of a positive electrode terminal with a plate thickness of 0.07 mm, although the welding and weld strength required for the terminal can be obtained, the positive electrode terminal breaks starting from the weld point (second welded part) when the weld strength is measured, so it is considered difficult to make the positive electrode terminal thinner than this. In the case of a positive electrode terminal with a plate thickness of 0.07 mm, the weld strength hardly improves even if the amount of heat during welding is increased, because the positive electrode terminal breaks during the weld strength test. If the positive terminal is too thin, it becomes difficult to obtain sufficient peel strength as a weld, and if the positive terminal is too thick, such as 0.2 mm or more, the elasticity of the terminal itself becomes too high, and the positive terminal will not be able to conform to the bottom surface of the positive can.

[0055] Fig. 11 is a graph showing the relationship between the depth of the weld and the weld strength relative to the thickness (0.15 mm) of the bottom wall of the positive electrode can. When the weld depth is 4 μm, the weld strength is 13.4 N, and it can be seen that when the weld depth is at least 5 μm, the necessary weld strength of 10 N or more can be obtained. [Explanation of symbols]

[0056] 1...battery, 2...positive electrode can, 2A...bottom surface (outer surface), 2a...center, 2b...periphery of one side, 2d...periphery of the other side, 3...negative electrode can, 4...gasket, 5...positive electrode mixture, 6...separator, 7...negative electrode mixture, 8...case, S...sealed space, 10...positive electrode terminal, 10A...positive electrode connection part, 10B...middle part, 10C...board connection part, 11...negative electrode terminal, 11C...board connection part, 15...first welded part, 16...second welded part, L...virtual line, G...gap, S...connection surface, 100, 20, 25, 30...button battery with terminals.

Claims

1. A terminal-equipped button battery comprising: flat cylindrical positive and negative electrode cans; a gasket for insulating and sealing the positive and negative electrode cans; and a positive terminal and a negative terminal fixed to bottom surfaces of the positive and negative electrode cans, respectively; The bottom surface of the positive electrode can is curved outwardly in a convex shape of 100 μm or less in a thickness direction when integrated with the negative electrode can, and the positive electrode terminal has a flat positive electrode connection portion, the positive electrode terminal has a positive electrode connection part which is connected to the positive electrode can by welding, an intermediate part which bends from the positive electrode connection part and extends toward the negative electrode can, and a substrate connection part which bends further from the intermediate part, extends in a direction away from the positive electrode can, and is connectable to a substrate; a positive electrode terminal arranged along a radial direction of a bottom surface of the positive electrode can, and a positive electrode connection portion inclined so as to form a tangent to the bottom surface at a position other than the center of the bottom surface in a cross-sectional view passing through the radial direction and perpendicular to the bottom surface, and fixed to the bottom surface.

2. A terminal-equipped button battery comprising: flat cylindrical positive and negative cans; gaskets for insulating and sealing the positive and negative cans; and positive and negative terminals fixed to the bottom surfaces of the positive and negative cans, respectively; The bottom surface of the positive electrode can is curved outwardly in a convex shape of 100 μm or less in a thickness direction when integrated with the negative electrode can, and the positive electrode terminal has a flat positive electrode connection portion, the positive electrode terminal has a positive electrode connection portion that is connected to the positive electrode can by welding, an intermediate portion that is bent at a substantially right angle from the positive electrode connection portion and extends toward the negative electrode can, and a board connection portion that is bent at a substantially right angle from the intermediate portion, extends in a direction away from the positive electrode can, and is connectable to a board; a positive electrode terminal arranged along a radial direction of a bottom surface of the positive electrode can, and a positive electrode connection portion inclined so as to form a tangent to the bottom surface at a position other than the center of the bottom surface in a cross-sectional view passing through the radial direction and perpendicular to the bottom surface, and fixed to the bottom surface.

3. A terminal-equipped button battery as described in Claim 2, characterized in that the board connection portion is inclined with respect to the connection surface of the board to which the board connection portion is connected.

4. A terminal-equipped button battery as described in any one of claims 1 to 3, characterized in that it is provided with a flat negative terminal connected to the negative can and having a substrate connection portion extending approximately flush with the substrate connection portion of the positive terminal.

5. A terminal-equipped button battery comprising: flat cylindrical positive and negative cans; gaskets for insulating and sealing the positive and negative cans; and positive and negative terminals fixed to the bottom surfaces of the positive and negative cans, respectively; The bottom surface of the positive electrode can is curved outwardly in a convex shape of 100 μm or less in a thickness direction when integrated with the negative electrode can, and the positive electrode terminal has a flat positive electrode connection portion, The positive electrode terminal is disposed along a radial direction of a bottom surface of the positive electrode can, and the positive electrode connection portion is inclined so as to form a tangent to the bottom surface at a position other than the center of the bottom surface in a cross-sectional view passing through the radial direction and perpendicular to the bottom surface, and is fixed to the bottom surface; a terminal-equipped button battery comprising a flat negative electrode terminal connected to the negative electrode can and having a substrate connection portion extending substantially flush with the substrate connection portion of the positive electrode terminal;

6. A terminal-equipped button battery described in any one of claims 1 to 5, characterized in that the positive terminal is welded to the positive electrode can at a position between the center of the bottom surface of the positive electrode can and the peripheral edge of the bottom surface of the positive electrode can with multiple welds.

7. A terminal-equipped button battery described in any one of claims 1 to 6, characterized in that the positive electrode terminal is made of a metal plate material and has a thickness of 0.07 to 0.15 mm.

8. A terminal-equipped button battery comprising: flat cylindrical positive and negative electrode cans; a gasket for insulating and sealing the positive and negative electrode cans; and a positive terminal and a negative terminal fixed to bottom surfaces of the positive and negative electrode cans, respectively; The bottom surface of the positive electrode can is curved outwardly in a convex shape of 100 μm or less in a thickness direction when integrated with the negative electrode can, and the positive electrode terminal has a flat positive electrode connection portion, The positive electrode terminal is disposed along a radial direction of a bottom surface of the positive electrode can, and the positive electrode connection portion is inclined so as to form a tangent to the bottom surface at a position other than the center of the bottom surface in a cross-sectional view passing through the radial direction and perpendicular to the bottom surface, and is fixed to the bottom surface; the positive electrode terminal has a positive electrode connection portion that connects to the positive electrode can, an intermediate portion that bends from the positive electrode connection portion and extends toward the negative electrode can, and a substrate connection portion that bends further from the intermediate portion and extends in a direction away from the positive electrode can, the negative electrode terminal has a plate-shaped negative electrode connection portion disposed along a surface of the negative electrode can and a substrate connection portion extending from the negative electrode connection portion in a direction away from the negative electrode can so as to be flush with the surface of the negative electrode can, The positive electrode terminal, in a cross-sectional view passing through the radial direction and perpendicular to the bottom surface, in which the positive electrode connection portion is disposed on top and the negative electrode connection portion is disposed on the bottom, A terminal-equipped button battery, characterized in that the substrate connection portion of the positive terminal is inclined so that the bent portion between the intermediate portion of the positive terminal and the substrate connection portion is positioned above the tip side of the substrate connection portion.

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