Button-type alkaline primary battery with terminals

Abstract

To provide a button type battery with a terminal.SOLUTION: A button type battery with a terminal according to the present invention has a positive electrode can and a negative electrode can in a flat cylindrical shape, a gasket insulating and sealing the positive electrode can and the negative electrode can, and a positive electrode terminal and a negative electrode terminal fixed to bottom faces of the positive electrode can and the negative electrode can. A bottom face of the positive electrode can is bent convexly outward in a thickness direction while integrated with the negative electrode can. The positive electrode terminal has a flat positive electrode connection part, and the positive electrode terminal is arranged along a radial direction of the bottom face of the positive electrode can. In a plan view area between a circumference of the bottom face of the positive electrode can and a virtual line passing through a center of the bottom face of the positive electrode can along a width direction of the positive electrode connection part, the positive electrode connection part is inclined in rear view with respect to the bottom face of the positive electrode can and is fixed to the bottom face.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention ,end is related to a coin-type battery with a child button. This application claims priority based on Japanese Patent Application No. 2021-042785 filed in Japan on March 16, 2021, and incorporates its content herein.

Background Art

[0002] In applications for small electronic devices, flat silver oxide batteries in coin or button form are used. This silver oxide battery has the characteristic that the voltage is stable for a long time by adopting silver oxide as the positive electrode active material (see Patent Document 1). When using a coin-type battery for small electronic device applications, attachment to a printed circuit board may be required. For example, in lithium batteries such as lithium secondary batteries and CR primary batteries, a technique of welding a lead terminal made of a nickel plate or the like to the battery and attaching it to the board by soldering is widely known (see Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the silver oxide battery described in Patent Document 1, a positive electrode mixture (a mixture of an active material, a conductive assistant, a binder, etc.) is arranged inside the bottom surface of the positive electrode can. Further, after incorporating a separator, a gasket, an electrolyte, and a negative electrode mixture into the positive electrode can, the negative electrode can is covered and placed on an assembly machine, and the positive electrode can is caulked on the peripheral side of the negative electrode can to produce the silver oxide battery. ​​Here, the positive electrode can is subjected to stress at the bottom surface during crimping, due to the combination of factors such as the crimping shape, the filling ratio of the active material and electrolyte relative to the internal volume, and the materials of the positive and negative electrode cans. This causes the positive electrode can to expand slightly in the thickness direction relative to its circumference, with the maximum expansion occurring near the center.

[0005] In particular, in alkaline primary batteries, including the silver oxide batteries mentioned above, the filling density of the active material and electrolyte is increased to obtain the largest possible discharge capacity, while the positive electrode casing is strongly crimped during assembly to prevent electrolyte leakage. At this time, stress is easily generated on the positive electrode casing, and expansion near the center of the positive electrode casing tends to occur. Furthermore, in non-aqueous button-type primary and secondary batteries, the positive electrode casing may expand in a similar manner to alkaline primary batteries, depending on the balance of various factors such as the filling density of the active material and electrolyte, the materials of the positive and negative electrode casings, and the stress during crimping.

[0006] The terminals welded to coin-type or button-type batteries come in various shapes for mounting on the circuit board or other components of the device they are installed on. Typically, the flat portion of the battery (the bottom surface of the positive or negative electrode casing) is welded to the flat portion of the terminal. Here, when welding a terminal to a positive electrode can that has expanded near its center as described above, if the terminal is placed across the center of the positive electrode can, the positive electrode can and the terminal will be in contact on one side of the terminal, but a gap will be created between the positive electrode can and the terminal on the other side of the terminal. Consequently, if, for example, a terminal is to be welded to a battery can using multiple weld points, the aforementioned gaps may affect the welding, potentially resulting in insufficient welds and a decrease in weld strength.

[0007] The present invention relates to a terminal-equipped battery with a configuration in which the battery can and terminals are stably joined. tree The objective is to provide a button-type alkaline primary battery. [Means for solving the problem]

[0008] (1) With terminal according to the present invention treeA button-type alkaline primary battery is a button-type battery with terminals, comprising a flattened 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 positive electrode terminals and negative electrode terminals fixed to the bottom surfaces of the positive electrode can and the negative electrode can, respectively. Alkaline primary A battery characterized in that the bottom surface of the positive electrode can is curved outward in a convex shape in the thickness direction by 100 μm or less while integrated with the negative electrode can, the positive electrode terminal has a flat positive electrode connection portion, the positive electrode terminal is arranged along the radial direction of the bottom surface of the positive electrode can, the positive electrode terminal has a positive electrode connection portion connected to the positive electrode can by welding, an intermediate portion that bends from the positive electrode connection portion and extends toward the negative electrode can side, and a substrate connection portion that bends further from the intermediate portion and extends away from the positive electrode can and can be connected to a substrate, and in a plan view region between a virtual line passing through the center of the bottom surface of the positive electrode can along the width direction of the positive electrode connection portion and the periphery of the bottom surface of the positive electrode can, the positive electrode connection portion is inclined with respect to the radial direction of the bottom surface of the positive electrode can, and is fixed in the region by a weld on the side closer to the virtual line and a weld on the side closer to the periphery of the bottom surface of the positive electrode can.

[0009] The aforementioned button type with terminals Alkaline primary According to the battery, the center line of the positive electrode connection part pixel of the positive electrode terminal is fixed at an angle to the radial direction of the bottom surface of the positive electrode can, allowing the positive electrode connection part to be connected to the bottom surface of the positive electrode can without any gaps. By connecting the positive electrode connection part in this way, the positive electrode terminal can be fixed in close contact with the bottom surface of the positive electrode can even if the bottom surface of the positive electrode can is bulging.

[0010] (2) Terminal-equipped according to one embodiment of the present invention tree In a button-type alkaline primary battery, it is preferable that the positive electrode terminal is arranged along the bottom surface of the positive electrode casing, and the positive electrode connection portion is arranged along the bottom surface of the positive electrode casing, extending from the center of the positive electrode casing toward the outer circumference of the positive electrode casing, and is inclined to be tangent to the bottom surface at a position other than the center of the bottom surface, and fixed to the bottom surface.

[0011] By fixing the positive electrode terminal with multiple welds in the aforementioned region, the positive electrode terminal can be fixed in close contact with the bottom surface of the positive electrode can, even if the bottom surface of the positive electrode can is bulging.

[0012] (3) Terminal-equipped according to one embodiment of the present invention tree In a button-type alkaline primary battery, the positive electrode terminal is fixed to the bottom surface of the positive electrode can by a first weld and a second weld, with one or more first welds formed on the side closer to the virtual line in the region, and one or more second welds formed on the side closer to the peripheral edge of the bottom surface of the positive electrode can.

[0013] Assuming that the bottom surface of the positive electrode can is curved outward in a convex shape, and the positive electrode terminals are positioned along the curved bottom surface, the positive electrode terminals can be securely fixed to the bottom surface of the positive electrode can by having the first weld on the central side of the bottom surface of the positive electrode can and the second weld on the peripheral side of the bottom surface of the positive electrode can.

[0014] (4) Terminal-equipped according to one embodiment of the present invention tree In a button-type alkaline primary battery, the positive electrode terminal can be made of a metal plate, and the thickness of the positive electrode terminal can be 0.07 to 0.15 mm.

[0015] If the thickness of the positive electrode terminal is between 0.07 and 0.15 mm, sufficient strength as a terminal can be ensured. In addition, when fixing the positive electrode terminal to the positive electrode can by welding, the welding machine can apply the appropriate amount of heat. If the thickness of the positive electrode terminal is thinner than the above range, the positive electrode terminal may break and be partially damaged during welding, and the welding strength may not be improved.

[0017] By having an intermediate section that bends from the positive electrode connection section and a substrate connection section that bends further from the intermediate section, when attaching the battery to a connection surface such as a terminal pad on a substrate, the substrate connection section can be attached to the connection surface of the substrate at a desired angle. Assuming that the positive electrode terminal is inclined along the curvature of the bottom surface of the positive electrode can and the substrate connection section is inclined at a small angle with respect to the connection surface, the small gap created between the substrate connection section and the connection surface can be effectively utilized as a solder reservoir. Therefore, it is possible to provide a button-type battery with terminals that has excellent bonding properties during soldering.

[0018] (5)Button type battery with terminal according to one embodiment of the present invention Alkaline primary In the battery, the positive electrode terminal preferably has a positive electrode connection portion connected to the positive electrode can by welding, an intermediate portion bent substantially at a right angle from the positive electrode connection portion and extending toward the negative electrode can side, and a substrate connection portion bent further substantially at a right angle from the intermediate portion and extending in a direction away from the positive electrode can and capable of being connected to a substrate.

[0019] With this configuration, when connecting the substrate connection portion to the substrate, soldering can be performed with the substrate connection portion slightly inclined with respect to the bonding surface of the substrate. When the substrate connection portion is slightly inclined with respect to the bonding surface of the substrate, a minute gap can be generated between the bonding surface of the substrate and the substrate connection portion. When soldering is performed on the portion with this gap, soldering can be performed while allowing solder to enter the aforementioned gap to form a solder pool. Therefore, it is possible to provide a button type battery with terminal that can provide a highly reliable bonding structure by soldering.

[0020] (6) In the present invention (1) to (5) the button type battery with terminal described in Alkaline primary in the battery, The positive terminal with respect to the connection surface of the substrate to which the substrate connection portion is connected, The positive terminal it is preferable that the substrate connection portion is inclined.

[0021] When connecting the substrate connection portion to the substrate, soldering can be performed with the substrate connection portion slightly inclined with respect to the bonding surface of the substrate. When the substrate connection portion is slightly inclined with respect to the bonding surface of the substrate, a minute gap can be generated between the bonding surface of the substrate and the substrate connection portion. When soldering is performed on the portion with this gap, soldering can be performed while allowing solder to enter the aforementioned gap to form a solder pool. Therefore, it is possible to provide a button type battery with terminal that can provide a highly reliable bonding structure by soldering.

[0022] (7) (1) of the present invention (6) the button type battery with terminal described in Alkaline primaryIn a battery, a configuration can be adopted in which a flat negative electrode terminal is connected to the negative electrode casing and has a substrate connection portion that extends substantially flush with the substrate connection portion of the positive electrode terminal.

[0023] By having a negative terminal in addition to a positive terminal, the battery can be mounted by connecting the board connection portion of the positive terminal to the board and the board connection portion of the negative terminal to the board. Furthermore, by providing a flat negative terminal that extends almost flush with the board connection portion of the positive terminal, the thickness of the button-type battery with terminals can be minimized. [Effects of the Invention]

[0024] Button type with terminal according to the present invention Alkaline primary In the case of a battery, the positive electrode connection portion of the positive electrode terminal is fixed at an inclination relative to the bottom surface of the positive electrode can in a plan view, in the region between a virtual line passing through the center of the bottom surface of the positive electrode can and the periphery of the bottom surface of the positive electrode can. This allows the positive electrode connection portion to be connected to the bottom surface of the positive electrode can without any gaps. By connecting the positive electrode connection portion in this way, even if the bottom surface of the positive electrode can is bulging, a structure can be provided in which the positive electrode terminal is securely fixed along the bottom surface of the positive electrode can. [Brief explanation of the drawing]

[0025] [Figure 1] This is a perspective view showing a button-type battery with terminals according to the first embodiment. [Figure 2] This is a plan view of a button-type battery with the same terminals. [Figure 3A] This is a side view of a button-type battery with the same terminals. [Figure 3B] This is a magnified view of a button-type battery with the same terminals. [Figure 4] This is a cross-sectional view of battery 1, which constitutes a button-type battery with terminals. [Figure 5] This is an explanatory diagram showing the desired welding range for the terminals of a button-type battery with the same terminals, relative to the battery casing. [Figure 6] This is a plan view showing a button-type battery with terminals according to the second embodiment. [Figure 7]This is a plan view showing a button-type battery with terminals according to the third embodiment. [Figure 8] This is a plan view showing a button-type battery with terminals according to the fourth embodiment. [Figure 9] This is an explanatory diagram of the welding strength test performed on the button-type battery with terminals manufactured in the example. [Figure 10] This graph shows the relationship between welding strength and heat quantity in the examples and comparative examples. [Figure 11] This graph shows the relationship between welding depth and welding strength in the examples and comparative examples. [Modes for carrying out the invention]

[0026] Hereinafter, an embodiment of the button-type battery with terminals 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.

[0027] <First Embodiment> Figures 1 to 4 are diagrams showing a button-type battery with terminals according to a first embodiment of the present invention. The battery 1 of this embodiment is a battery in which a positive electrode mixture, a negative electrode mixture, and an electrolyte, etc., described later, 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. Thus, the button battery 100 with terminals 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.

[0028] The outline of the internal structure of the battery 1 is shown in FIG. 4. The positive electrode can 2 is made of, for example, a material obtained by nickel-plating stainless steel (SUS) and is formed into a flat cylindrical shape (shallow-bottomed cup shape). This positive electrode can 2 houses the positive electrode mixture 5 and functions as a positive electrode current collector. The negative electrode can 3 is made of a clad material having a three-layer structure including, for example, 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 formed into a flat cylindrical shape (shallow-bottomed cup shape). Further, the circular opening 3a of the negative electrode can 3 is formed by folding back, and a ring-shaped gasket 4 made of, for example, nylon is attached to the opening 3a.

[0029] The negative electrode can 3 is fitted into the circular opening 2f of the positive electrode can 2 from the side of the opening 3a to which the gasket 4 is attached, and the opening 2f of the positive electrode can 2 is caulked toward the gasket 4 to seal it, thereby forming a disk-shaped (button-shaped or coin-shaped) case 8. A sealed 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. The positive electrode mixture 5, the separator 6, and the negative electrode mixture 7 are housed in the sealed space 8S, and the positive electrode mixture 5 is disposed on the positive electrode can 2 side and the negative electrode mixture 7 is disposed on the negative electrode can 3 side with the separator 6 interposed therebetween.

[0030] When assembling this battery 1, the positive electrode mixture 5 formed into pellets is filled into the positive electrode can 2. Further, the separator 6 is laid on the positive electrode mixture 5, and the gasket 4 is press-fitted into the positive electrode can 2. Then, the gel-like negative electrode mixture 7 is placed on the separator 6, and the negative electrode can 3 is placed thereon. Further, the opening edge of the positive electrode can 2 is caulked to seal the case 8. The caulked state is, for example, the difference 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 (H2 - H1). For example, in the case of an SR716SW (outer diameter 7.9 mm, height 1.6 mm) type silver oxide battery, it is 0.10 to 0.15 mm. Further, 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.

[0031] The positive electrode mixture 5 includes a positive electrode active material, a conductive agent, an electrolyte, a binder, additives, 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. Alternatively, the positive electrode active material may be nickel oxyhydroxide alone, or nickel oxyhydroxide in which cobalt or the like is solid-solved. Graphite or the like can be used as the conductive additive. Hydrogen storage alloys (LaNi5) or the like can be used as additives.

[0032] The negative electrode mixture 7 includes, for example, a negative electrode active material, a conductivity stabilizer, a gelling agent, an electrolyte, a viscoelastic modifier, and additives (thickeners, resin powders). For example, zinc powder or zinc alloy powder can be used as the negative electrode active material. Zinc oxide (ZnO) or the like can be used as the conductivity stabilizer. Furthermore, carboxymethylcellulose, polyacrylic acid, or a mixture of carboxymethylcellulose and polyacrylic acid are preferred as the gelling agent. By using carboxymethylcellulose or polyacrylic acid, the hydrophilicity and liquid retention properties of the negative electrode mixture 7 with respect to the electrolyte can be improved.

[0033] The electrolyte can be an aqueous solution of potassium hydroxide, an aqueous solution of sodium hydroxide, or a mixture thereof. The viscoelastic modifier is added to the negative electrode mixture 7 to achieve a viscoelasticity that provides good handling properties and improves productivity. A resin powder that does not react with the strongly alkaline electrolyte is used as this viscoelastic modifier. Here, a state of not reacting with the electrolyte and not absorbing it is defined as a state of not reacting with the electrolyte.

[0034] The separator 6 is interposed between the positive electrode mixture 5 and the negative electrode mixture 7, and an insulating film having high ion permeability and mechanical strength is used. As the separator 6, any material conventionally used as a battery separator can be applied without any limitations. For example, a microporous membrane such as polyethylene film, cellophane, or graft polymerized film, or a nonwoven fabric such as liquid-absorbing paper made of cellulose can be used. Furthermore, these microporous membranes and nonwoven fabrics may be used in combination.

[0035] As described above, the battery 1 shown in Figures 1 to 4 has a case 8 formed by crimping the open edge of the positive electrode can 2 and integrating it with the negative electrode can 3. Furthermore, because the case 8 is filled with as much positive electrode mixture 5, negative electrode mixture 7, and electrolyte as possible, after crimping the positive electrode can 2, the bottom surface (outer surface) 2A of the positive electrode can 2 may be curved due to the crimping stress, causing the center of the bottom surface 2a of the positive electrode can 2 to bulge outwards in a convex shape. When the bottom surface 2A of the positive electrode can 2 is curved, the amount of bulge (curve height) at the center of the bottom surface (center of the outer surface) 2a is 100 μm or less compared to when it is not curved.

[0036] 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 (metal sheet material) of a highly conductive metal material 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 between 0.07 and 0.15 mm, sufficient strength as a 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 the 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 welding strength may not be improved. The positive electrode terminal 10 has a strip-shaped positive electrode connection portion 10A arranged along the bottom surface 2A of the positive electrode can 2, an intermediate portion 10B extending approximately perpendicular to the positive electrode connection portion 10A, and a flat substrate connection portion 10C extending approximately perpendicular to the intermediate portion 10B. The intermediate portion 10B is tapered, and the substrate connection portion 10C, which has a width of about 1 / 4 of the positive electrode connection portion 10A, extends from the intermediate portion 10B. The board connection portion 10C is the part that is soldered to a connection surface S (see Figure 3), such as a terminal pad, formed on the board on which the battery 1 of this embodiment is mounted. Therefore, the board connection portion 10C becomes a connection portion that can be connected to the board.

[0037] The negative electrode terminal 11 has a strip-shaped negative electrode connection portion 11A arranged along the surface of the negative electrode can 3 and a substrate connection portion 11C extending from one end of the negative electrode connection portion 11A. The substrate connection portion 11C is formed to extend flush with the plate-shaped negative electrode connection portion 11A. The substrate connection portion 11C, like the substrate connection portion 10C on the positive electrode side, is the part that is soldered to a connection surface S such as a terminal pad formed on the substrate on which the battery 1 of this embodiment is mounted. The length and width of the substrate connection portion 11C of the negative electrode terminal 11 are appropriately set to match the size of the terminal pad formed on the substrate on which the battery 1 of this embodiment is mounted. As an example, as shown in Figure 1, the substrate connection portion 11C is formed to be approximately the same length and width as the substrate connection portion 10C of the positive electrode terminal 10. The substrate connection portion 10C extends in the direction away from the positive electrode can 2. The negative electrode terminal 11 is welded to the bottom surface (outer surface) of the negative electrode can 3 such that its substrate connection portion 11C is adjacent to the substrate connection portion 10C of the positive electrode terminal 10. The negative electrode terminal 11 is flat overall and extends along the bottom surface of the negative electrode can 3.

[0038] In the positive electrode terminal 10 described above, the length of the positive electrode connection portion 10A is formed to be slightly shorter than the diameter of the bottom surface 2A, and the length of the intermediate portion 10B is formed to be equivalent to the thickness of the case 8, which consists of the positive electrode can 2 and the negative electrode can 3. Therefore, when the positive electrode connection portion 10A is aligned with the bottom surface (outer surface) 2A of the positive electrode can 2, the intermediate portion 10B extends from the bottom to the top of the case 8 along the thickness direction of the case 8, and the substrate connection portion 10C is positioned almost flush with the surface of the negative electrode can 3.

[0039] In this embodiment, as shown in Figure 1, the positive electrode connection portion 10A is positioned in the positive electrode can 2 along the diameter of the bottom surface 2A (radial direction), the intermediate portion 10B is slightly spaced outwards from the side surface of the case 8, and the substrate connection portion 10C is positioned so as to be almost flush with the surface of the negative electrode can 3. In other words, the positive terminal 10 is positioned at the center 2a of the base surface 2A and passing through one side of the base surface 2A's peripheral edge 2b along the radial direction from the center 2a. Furthermore, the length of the positive terminal connection portion 10A is longer than the radius of the base surface 2A and shorter than its diameter. For this reason, the tip portion 10a of the positive terminal connection portion 10A extends beyond the center 2a of the base surface 2A to a position midway between the center 2a and the other side of the base surface 2A's peripheral edge 2d. Furthermore, the position of the tip 10a in the positive electrode connection portion 10A does not need to extend beyond the center 2a. That is, although the position of the tip 10a is to the left of the center 2a in Figure 3, the position of the tip 10a may also be to the right of the center 2a. Therefore, the length of the positive electrode connection portion 10A may be shorter than the radius of the base surface 2A.

[0040] In this embodiment, a circular first welded portion 15 is formed in the positive electrode connection portion 10A of the positive electrode terminal 10, on the portion facing the center 2a of the bottom surface of the positive electrode can 2. In addition, two circular second welded portions 16 are formed in the positive electrode connection portion 10A of the positive electrode terminal 10, spaced apart in the width direction of the positive electrode terminal 10, near the peripheral edge 2b of the bottom surface of the positive electrode can 2, so as to sandwich the center line of the positive electrode connection portion 10A. The first weld 15 and the second weld 16 are both welds formed by laser welding. The maximum welding depth of the first weld 15 and the second weld 16 to the bottom wall of the positive electrode can is preferably 5 μm or more relative to the thickness of the bottom wall of the positive electrode can. The diameters of the first weld 15 and the second weld 16 should preferably be in the range of 0.3 to 0.7 mm.

[0041] In this embodiment, the formation position of the first weld 15 is preferably at or near the center 2a on the bottom surface 2A of the positive electrode can 2. The vicinity of the center 2a is the side closer to the imaginary line L when an imaginary line L is drawn along the width direction of the positive electrode connection portion 10A passing through the center 2a, as shown in Figure 5, within the shaded region E that is demarcated between the imaginary line L and the periphery 2b of the bottom surface 2A. In this embodiment, the formation position of the second weld 16 is on the side closer to the peripheral edge 2b in the region E demarcated by diagonal lines between the imaginary line L and the peripheral edge 2b of the bottom surface 2A, as shown in Figure 5. Therefore, the second weld 16 is formed on the side closer to the peripheral edge 2b than the first weld 15. Therefore, the positive electrode connection portion 10A is fixed to the bottom surface 2A of the positive electrode can 2 by welding along the bottom surface 2A of the positive electrode can 2 at a position of the second weld 16 other than the center, with an inclination of tangency t at this welding position. In other words, the positive electrode connection portion 10A is fixed to the bottom surface 2A with an inclination such that it forms a tangency t with the bottom surface 2A at a position other than the center of the bottom surface 2A, in a cross-sectional view that passes through the radial direction of the bottom surface 2A and is perpendicular to the bottom surface 2A. The distance between the center 2a of the bottom surface 2A and the second weld 16 varies depending on the outer diameter of the positive electrode can 2. For a battery 1 with an outer diameter of approximately ψ4mm to ψ12mm, the distance can be selected from a range of approximately 1mm to 5mm.

[0042] A button-type battery 100 equipped with a positive terminal 10 and a negative terminal 11 is attached to the connection surface S of a terminal pad on a circuit board or the like, equipped with an electrical circuit, by soldering. The button-type battery 100 equipped with a terminal, equipped with a circuit board connection portion 10C of the positive terminal 10 and a circuit board connection portion 11C of the negative terminal 11, can be mounted on the circuit board by bringing it into contact with the terminal pad (connection surface) of the circuit board and soldering it, as shown in Figure 1.

[0043] In the button-type battery 100 with terminals of this embodiment, a first welded portion 15 and a second welded portion 16 are formed at the above-mentioned positions, and furthermore, the bottom surface 2A is convexly bulging in a range of 100 μm or less. For this reason, the positive electrode terminal 10 is attached to the positive electrode can 2 at a slight inclination along the bottom surface 2A which forms a convex curved surface. If the bottom surface 2A were flat instead of convex, the intermediate portion 10B would be parallel to the central axis of the case 8, and the substrate connection portion 10C would be almost flush with the surface of the negative electrode can 3.

[0044] In contrast, if 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 such that the side closer to the peripheral edge 2b of the bottom surface 2A is closer to the negative electrode can 3 than the side closer to the center 2a. As shown in Figure 3, the positive electrode connection portion 10A is inclined along the tangent line t such that the right end is lower than the left end. Due to this inclination, the substrate connection portion 10C also inclins downward to the right, as shown in an enlarged view in Figure 3. When the substrate connection portion 10C is brought into contact with a connection surface S such as a terminal pad on the substrate, the base end (middle part) of the substrate connection portion 10C lifts slightly from the connection surface S, creating a small gap G. Solder flows into this gap G during soldering, forming a solder reservoir. For this reason, the structure with the above-described substrate connection portion 10C is advantageous when soldering.

[0045] In the button-type battery 100 with terminals as described above, the positive electrode connection portion 10A is positioned along the curved bottom surface 2A, and in region E, a first weld portion 15 is formed on the side closer to the center 2a, and a second weld portion 16 is provided in region E on the side closer to the periphery 2b than the first weld portion 15. Therefore, the first weld portion 15 and the second weld portion 16 can be positioned in or near the portion where the positive electrode connection portion 10A is positioned along the bottom surface 2A. Thus, the first weld portion 15 and the second weld portion 16 can be obtained as reliable welds by laser welding.

[0046] Furthermore, in the button-type battery 100 with terminals as described above, a flat negative terminal 11 is provided, so the thickness of the battery can be minimized as a button-type battery with terminals 100. In addition, the button-type battery 100 with terminals has the positive terminal 10 as described above, and as mentioned above, it is inclined with respect to the connection surface S of the substrate with a gap G in between, and soldering is possible using solder accumulation, in which case the substrate connection portion 11C can be placed in close contact with the connection surface S of the substrate to be connected without any gaps and soldered.Therefore, soldering can be performed without applying a load that would bend the substrate connection portion 11C of the negative terminal 11 toward the positive terminal can 2. Furthermore, since soldering can be performed without applying load to the negative terminal 11, a short circuit with the positive terminal can 2 due to deformation of the negative terminal 11 can be prevented.

[0047] Figure 6 shows a button-type battery with terminals according to a second embodiment of the present invention. The button-type battery with terminals 20 of this second embodiment differs from the button-type battery with terminals 100 of the first embodiment in the position and number of second welds 16 provided on the positive electrode connection 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, a circular second weld portion 16 is formed in the center in the width direction of the positive electrode terminal 10, at a position close to the peripheral edge 2b of the bottom surface 2A of the positive electrode can 2.

[0048] In the structure of the first embodiment, two second welds 16 were provided on the bottom surface 2A at a position close to the periphery 2b, but in the second embodiment, one second weld 16 is provided at a position close to the periphery 2b. As shown in the second embodiment in Figure 6, there may be only one second weld 16. Even with the button-type battery 20 with terminals of the second embodiment, the same effects and advantages as the button-type battery 1 with terminals of the first embodiment can be obtained.

[0049] Figure 7 shows a button-type battery with terminals according to a third embodiment of the present invention. This button-type battery with terminals 25 of the third embodiment is characterized by having a third welded portion 26 compared to the button-type battery with terminals 20 of the second embodiment.

[0050] The third embodiment of the button-type battery 25 with terminals differs in that a third welded portion 26 is provided between the first welded portion 15 and the second welded portion 16 provided in the second embodiment. Even with the button-type battery 25 with terminals of the third embodiment, the same effects and advantages as the button-type battery 100 with terminals of the first embodiment can be obtained.

[0051] Figure 8 shows a button-type battery with terminals according to a fourth embodiment of the present invention. This button-type battery with terminals 30 of the fourth embodiment is characterized by having two first welded parts 15 and two second welded parts 16 compared to the button-type battery with terminals 100 of the first embodiment. In the structure of the fourth embodiment, as shown in Figure 8, when a virtual line L is drawn along the width direction of the positive electrode connection portion 10A passing through the center 2a, two first welds 15 are formed spaced apart along the virtual line L. Two second welds 16 are also formed near the periphery 2b so as to be parallel to the two first welds 15. In the fourth embodiment, two first welds 15 and two second welds 16 are provided, but there is no particular limit on the number of each weld installed. Even with the button-type battery 30 with terminals of the fourth embodiment, the same effects and advantages as the button-type battery 100 with terminals of the first embodiment can be obtained. [Examples]

[0052] A prototype button-type silver oxide battery with an outer diameter of 7.9 mm and a thickness of 1.65 mm, as shown in Figure 4, was fabricated and subjected to testing. Both the positive and negative electrode casings of this button-type battery are made of stainless steel, with the thickness of the stainless steel constituting the inner and bottom walls of the positive and negative electrode casings being 0.15 mm and 0.23 mm, respectively. As shown in Figure 4, a battery prototype was fabricated by placing the positive electrode mixture, separator, negative electrode mixture, and electrolyte inside the positive electrode can and negative electrode can, attaching a gasket, and crimping the positive electrode can to seal it. Furthermore, because the positive electrode mixture and negative electrode mixture were filled into the sealed space between the positive electrode can and the negative electrode can, the crimping of the positive electrode can resulted in a convex curvature of less than 100 μm at the center of the bottom surface of the positive electrode can. Several prototype batteries with the above structure were fabricated. The convex curvature on the bottom of the positive electrode casing varied depending on the battery fabricated, but in all cases it fell within the range of 5 μm to 70 μm.

[0053] Positive terminals, as shown in Figure 1, were welded to these prototype batteries. The positive terminals were made of stainless steel (SUS304), and four types of positive terminals with thicknesses of 0.07 mm, 0.10 mm, 0.15 mm, and 0.20 mm, as shown in Table 1 below, were used. The length of the positive terminal connection part was 6 mm and the width was 2 mm. As shown in Figure 1, the welding locations were set to a total of three: one at the center of the bottom surface of the positive electrode can, and two at a distance of 1 mm in the plate width direction of the positive electrode joint, 2 mm away from the periphery of the bottom surface and 1 mm away from the center of the bottom surface. Since the amount of heat that can be applied by the laser welding machine can be adjusted, welding was performed on the positive electrode terminals of the four plate thicknesses mentioned above, with the amount of heat applied by the laser welding machine set 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 welding strength of the laser-welded positive electrode terminals was measured according to the following method.

[0054] "Welding strength test" The welding strength test was performed by bending the tip of the substrate connection part 10C perpendicular to the welding surface (bottom surface 2A) relative to the battery 1, as shown in Figure 9. Next, the tip of the bent substrate connection part 10C was clamped in a jig, the battery 1 was held down while avoiding the terminal portion, and the substrate connection part 10C was pulled in the direction of arrow F in Figure 9. After that, the force at which the second weld part 16 peeled off from the bottom surface 2A was recorded with a force gauge and defined as the welding strength. Table 2 below shows the terminal thickness, the amount of heat used during laser welding, and the resulting weld strength of the second weld.

[0055] [Table 1]

[0056] [Table 2]

[0057] The relationship between the amount of heat during welding and the terminal thickness, as shown in the measurement results in Table 2, is summarized in a graph as shown in Figure 10, with the amount of heat (J) on the horizontal axis and the welding strength (N) on the vertical axis. As shown in the graph in Figure 10 and Table 2, if the lower limit of the welding strength is set to 10N, it can be seen that for three types of positive electrode terminals with thicknesses of 0.07mm, 0.10mm, and 0.15mm, a sufficiently high welding strength can be obtained by welding with a heat load of approximately 2.6J to 4.5J. A positive electrode terminal with a thickness of 0.20 mm requires a high welding heat of 6.0 J to achieve satisfactory weld strength. Applying 6.0 J of heat during welding unnecessarily heats the inside of the battery, raising concerns about adverse thermal effects on the battery active material and electrolyte. In particular, in the case of silver oxide batteries, a good weld can be obtained while preventing the degradation of silver oxide. Based on the results shown in Figure 10, it is considered desirable to use terminals with a plate thickness in the range of 0.07 to 0.15 mm in order to ensure welding strength without applying excessive heat.

[0058] Furthermore, in the case of a positive electrode terminal with a plate thickness of 0.07 mm, while welding and welding strength can be obtained as a terminal, the positive electrode terminal breaks starting from the welding point (second weld) during welding strength measurement, making it difficult to make the positive electrode terminal any thinner. In the case of a positive electrode terminal with a plate thickness of 0.07 mm, increasing the amount of heat during welding does not significantly improve the welding strength because the positive electrode terminal breaks during the welding strength test. If the positive electrode terminal is too thin, it becomes difficult to obtain sufficient peel strength for the welded joint. If the positive electrode terminal is too thick, such as 0.2 mm or more, the elasticity of the terminal itself becomes too high, and the positive electrode terminal will not be able to conform to the bottom surface of the positive electrode can.

[0059] Figure 11 is a graph showing the relationship between the depth of the weld and the weld strength relative to the thickness of the bottom wall of the positive electrode can (0.15 mm). It can be seen that when the weld depth is 4 μm, the weld strength is 13.4 N, and that the required weld strength of 10 N or more can be obtained when the weld depth is at least 5 μm or more. [Explanation of Symbols]

[0060] 1...Battery, 2...Positive electrode casing, 2A...Bottom surface (outer surface), 2a...Center, 2b...Periphery on one side, 2d...Periphery on the other side, 3...Negative electrode casing, 4...Gasket, 5...Positive electrode mixture, 6...Separator, 7...Negative electrode mixture, 8...Case, 8S...Sealed space, 10...Positive electrode terminal, 10A...Positive electrode connection part, 10B...Intermediate part, 10C...Board connection part, 11...Negative electrode terminal, 11C...Board connection part, 15...First weld, 16...Second weld, L...Dummy line, G...Gap, S...Connection surface, 100, 20, 25, 30...Button-type battery with terminals.

Claims

1. A button-type alkaline primary battery with terminals, comprising a flattened 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 surfaces of the positive electrode can and the negative electrode can, respectively, The bottom surface of the positive electrode can is curved outward in the thickness direction by 100 μm or less in a convex shape while integrated with the negative electrode can, and the positive electrode terminal has a flat positive electrode connection portion, The positive electrode terminal is arranged along the radial direction of the bottom surface of the positive electrode can. 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 from the positive electrode connection portion and extends toward the negative electrode can, and a substrate connection portion that is further bent from the intermediate portion and extends away from the positive electrode can, and is connectable to a substrate. A button-type alkaline primary battery with terminals, characterized in that, in a plan view region between a virtual line passing through the center of the bottom surface of the positive electrode can along the width direction of the positive electrode connection portion and the periphery of the bottom surface of the positive electrode can, the positive electrode connection portion is inclined with respect to the radial direction of the bottom surface of the positive electrode can, and is fixed in the region by a weld on the side closer to the virtual line and a weld on the side closer to the periphery of the bottom surface of the positive electrode can.

2. The button-type alkaline primary battery with terminals according to claim 1, characterized in that the positive electrode terminal is arranged along the bottom surface of the positive electrode can, the positive electrode connection portion is arranged along the bottom surface of the positive electrode can from the center toward the outer circumference of the positive electrode can, is inclined to be tangent to the bottom surface at a position other than the center of the bottom surface and is fixed to the bottom surface.

3. The button-type alkaline primary battery with a terminal according to claim 1 or 2, characterized in that the positive electrode terminal is fixed to the bottom surface of the positive electrode can by a first weld and a second weld, one or more first welds are formed on the side closer to the imaginary line in the region, and one or more second welds are formed on the side closer to the periphery of the bottom surface of the positive electrode can in the region.

4. The button-type alkaline primary battery with terminals according to claim 1 or 2, characterized in that the positive terminal is made of a metal plate and the thickness of the positive terminal is 0.07 to 0.15 mm.

5. The positive electrode terminal is characterized by having a positive electrode connection portion that is connected to the positive electrode can by welding, an intermediate portion that bends substantially at a right angle from the positive electrode connection portion and extends toward the negative electrode can, and a substrate connection portion that bends further substantially at a right angle from the intermediate portion and extends toward away from the positive electrode can, and is connectable to a substrate, as described in any one of claims 1 to 4.

6. A button-type alkaline primary battery with a terminal according to any one of claims 1 to 5, wherein the substrate connection portion of the positive terminal is inclined with respect to the connection surface of the substrate to which the substrate connection portion of the positive terminal is connected.

7. A button-type alkaline primary battery with a terminal according to any one of claims 1 to 6, characterized in that it is provided with a flat negative electrode terminal connected to the negative electrode can and having a substrate connection portion that extends substantially flush with the substrate connection portion of the positive electrode terminal.

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