Battery

Abstract

To provide a battery having a structure that causes little interference with an electrode when the electrode is fixed to the bottom of an outer can.SOLUTION: A battery 1 houses an electrode body 3, which is formed by winding a positive electrode plate 11 and a negative electrode plate 12 facing each other with a separator 13 interposed therebetween, in a cylindrical outer can 2 with a bottom. A current collector 10 has an opening 10a in the center, and is attached to one end of the electrode body in the axial direction. A fixing member 5 is conductive and is fixed to the bottom of the outer can. The fixing member includes a protrusion 7 that protrudes toward the current collector. The opening of the current collector is pushed toward the protrusion to fix the current collector to the outer can, and the current collector is electrically connected to the outer can via the fixing member.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a battery, and more particularly to a battery in which an electrode assembly is fixed to the bottom of an outer can. [Background technology]

[0002] In general, an alkaline storage battery is formed by interposing a separator between a positive electrode and a negative electrode, winding them into a spiral shape, and then connecting a current collector to the end of the negative electrode to form a cylindrical electrode body. After this electrode body is housed in a metal outer container, a welding rod is inserted into a cavity extending axially in the center of the cylindrical electrode body to weld the current collector to the outer container. Then, a current collector having a current collector lead is welded to the end of the positive electrode, and the outer container is filled with electrolyte. Next, the current collector lead is welded to a sealing body, and the sealing body is attached to the opening of the outer container via an insulating gasket to seal the opening. Next, a positive electrode terminal is attached to the sealing body to complete the battery.

[0003] As described above, in order to weld the current collector to the outer container, a welding rod was inserted into the hollow core portion at the center of the spiral electrode body, and resistance welding was performed between the current collector and the outer container to fix the electrode body to the outer container.

[0004] However, when the welding rod comes into contact with the electrode during resistance welding, the electrode body can be damaged. Therefore, instead of welding the current collector to the outer container, a structure has been adopted in which a protrusion is provided on the inner bottom surface of the outer container, the central opening of the current collector is fitted into the protrusion, and then the protrusion is crushed to fix the current collector to the bottom of the outer container. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-257470 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, a tool inserted into the hollow core portion at the center of the electrode body to crush the protrusion may accidentally interfere with the electrode body and damage the electrode body.

[0007] SUMMARY OF THE PRESENT INVETION In order to solve the above problems, an object of the present invention is to provide a battery having a structure that causes little interference with the electrode body when the electrode body is fixed to the bottom of an outer can. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the battery of the present invention is a battery in which an electrode body formed by winding a positive electrode plate and a negative electrode plate facing each other with a separator interposed therebetween is housed in a cylindrical outer can with a bottom, and is equipped with a current collector having an opening in the center and attached to one end in the axial direction of the electrode body, and a conductive fixing member fixed to the bottom of the outer can, wherein the fixing member has a protrusion that protrudes toward the current collector, and the opening of the current collector is pushed toward the protrusion to fix the current collector to the outer can, and the current collector is electrically connected to the outer can via the fixing member. Effect of the Invention

[0009] According to the battery of the present invention, the electrode body can be fixed to the bottom of the outer can and electrically connected to the outer can without inserting a tool into the hollow core portion at the center of the cylindrically wound electrode body. [Brief description of the drawings]

[0010] [Figure 1] 1 is a partially cutaway, exploded perspective view of a battery according to one embodiment; [Diagram 2] FIG. 2A is a perspective view of a fixing plate, and FIG. 2B is a cross-sectional view of the fixing plate attached to an outer can. [Diagram 3] FIG. 2 is a plan view showing a state in which a negative electrode plate, a separator, and a positive electrode plate are stacked. [Figure 4] FIG. [Diagram 5] 4 is a cross-sectional view showing an electrode body fixed to the bottom of an outer can via a fixing plate. FIG. [Figure 6] FIG. 13 is a perspective view showing a modified example of the fixing plate. [Figure 7] FIG. 1 is a diagram illustrating the attachment of an electrode assembly having a negative electrode current collector to a fixing plate fixed to an outer can. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, a battery according to an embodiment of the present invention will be described with reference to the drawings. 1. Battery configuration A cylindrical battery is shown in Figure 1. Battery 1 has a spiral electrode body 3 housed together with an alkaline electrolyte in a cylindrical outer can 2, and an opening 2A of the outer can 2 is sealed with a sealing body 4. The outer can 2 functions as the negative electrode, and the sealed end of the outer can 2 functions as the positive electrode.

[0012] The exterior can 2 is made of a conductive metal and formed into a cylindrical shape, has a cylindrical side portion 2B extending in the axial direction, one end in the axial direction is a circular can bottom 2C, and the other end is open. A fixing member 5 is welded to the can bottom 2C by resistance welding.

[0013] The fixing member 5 is made of a conductive metal, and as shown in FIG. 2(A), has a fixing plate 6 and a protrusion 7 rising from the center of the fixing plate 6. The fixing member 5 is formed by pressing a metal plate. The fixing plate 6 is a disk having the same diameter as the inner diameter of the can bottom 2C, and the outer edge is welded to the can bottom 2C of the outer can 2 by resistance welding, so that the fixing member 5 is electrically connected to the outer can 2. The protrusion 7 has a shaft portion 8 extending from the center of the fixing plate 6 in the axial direction of the battery 1, and a circular head portion 9 provided at the tip of the shaft portion 8. The shaft portion 8 has a substantially circular cross section perpendicular to the axial direction. The head portion 9 has a surface 6C, whose peripheral portion spreads outward in the radial direction from the shaft portion 8 and faces the can bottom 2C, as a seat surface 9A. The seat surface 9A abuts against a negative electrode current collector 10 described later, thereby fixing the electrode body 3 to the can bottom 2C of the outer can 2. The shaft portion 8 has a cross-sectional diameter D0. The upper and lower ends of the side surfaces of the head 9 are curved to facilitate passage through an opening in a negative electrode current collector, which will be described later. The head 9 has a maximum diameter D1 (where D1>D0) in a cross section perpendicular to the axial direction.

[0014] The electrode body 3 has a strip-shaped positive electrode plate 11, a negative electrode plate 12, and a separator 13. The electrode body 3 is spirally wound with the separator 13 sandwiched between the positive electrode plate 11 and the negative electrode plate 12, and has an approximately cylindrical shape as a whole. When the positive electrode plate 11, the separator 13, and the negative electrode plate 12 are wound, the negative electrode plate 12, the separator 13, and the positive electrode plate 11 are stacked in this order, as shown in FIG. 3. At this time, while aligning the longitudinal directions of the negative electrode plate 12 and the positive electrode plate 11, the positive electrode plate 11 is slightly shifted to one side in the width direction relative to the negative electrode plate 12, and then the electrode body 3 is wound with the longitudinal direction of the positive electrode plate 11 and the negative electrode plate 12 as the winding direction, with the width direction of the positive electrode plate 11 and the negative electrode plate 12 as the axis.

[0015] By winding the electrode plates 11, 12 in this manner, the edge of the negative electrode plate 12 protrudes in a spiral shape at one axial end of the electrode body 3, and the edge of the positive electrode plate 11 protrudes in a spiral shape at the other end. The outermost periphery of the electrode body 3, i.e., the side surface, is composed only of the negative electrode plate 12. Furthermore, an air core portion S is formed in the center of the spirally wound electrode body 3, penetrating from one end to the other end along the axial direction. As shown in FIG. 5, the air core portion S is substantially cylindrical, and the diameter of the cross section perpendicular to the axial direction is D S In order to avoid contact with the protrusion 7 of the fixing member 5 disposed inside the hollow core portion S when the battery 1 is assembled, the diameter D1 of the head 9 of the protrusion 7 is set to be smaller than the diameter D S It is shorter than

[0016] In the electrode body 3 assembled in this manner, the negative electrode current collector 10 is welded to one end where the edge portion of the negative electrode plate 12 protrudes, and the negative electrode plate 12 is electrically connected to the negative electrode current collector 10.

[0017] As shown in FIG. 4, the negative electrode current collector 10 is a regular hexagonal plate made of a conductive metal and having a thickness T1, and has a circular opening 10a in the center of the plate. The opening 10a is formed to have a diameter D2. The opening 10a is formed so that the diameter D2 is larger than the diameter D0 of the shaft portion 8 so that the shaft portion 8 of the protrusion 7 can be inserted therein. The negative electrode current collector 10 is an example of a current collector. The shape of the negative electrode current collector 10 may be circular.

[0018] The electrode assembly 3 to which the negative electrode current collector 10 is welded is housed in the outer can 2 so that the negative electrode current collector 10 faces the can bottom 2C of the outer can 2. At this time, the opening 10a of the negative electrode current collector 10 is aligned with the protrusion 7 of the fixing member 5, the opening 10a is fitted into the protrusion 7, and the head 9 of the protrusion 7 is passed through the opening 10a, and as shown in FIG. 5, the peripheral portion of the opening 10a of the negative electrode current collector 10 is sandwiched in the gap between the seat surface 9A and the upper surface 6A of the fixing plate 6. As a result, the negative electrode current collector 10 is fixed to the can bottom 2C by the fixing member 5. Therefore, the negative electrode plate 12 is electrically connected to the outer can 2 via the negative electrode current collector 10 and the fixing member 5. The head 9 of the protrusion 7 inserted into the hollow core portion S has a diameter D1 that is larger than the diameter D of the hollow core portion S. S Since the length of the protrusion 7 is shorter than the length of the hollow core S, contact between the head 9 of the protrusion 7 and the inner surface of the hollow core S is avoided. The upper surface 6A of the fixing plate 6 is an example of an opposing surface of a fixing member.

[0019] In order to allow the head 9 of the protrusion 7 to pass through the opening 10a and to bring the seating surface 9A into contact with the periphery of the opening of the negative current collector 10, the maximum diameter D1 of the head 9 is larger than the diameter D2 of the opening 10a of the negative current collector 10, and the ratio of the maximum diameter D1 of the head 9 to the diameter D2 of the opening 10a of the negative current collector 10 is 8:7. Furthermore, if the diameter D2 of the opening 10a of the negative current collector 10 is 88% or more and less than 100% of the maximum diameter D1 of the head 9, the head 9 of the protrusion 7 passes through the opening 10a of the negative current collector 10, and the periphery of the opening of the negative current collector 10 is fitted between the seating surface 9A of the protrusion 7 and the upper surface 6A of the fixing plate 6, thereby fixing the negative current collector 10. As a result, the negative current collector 10 is fixed to the can bottom 2C of the outer can 2 via the fixing member 5 and electrically connected. If the diameter D2 of the opening 10a of the negative electrode current collector 10 is less than 88% of the maximum diameter D1 of the head 9, it becomes difficult to insert the head 9 of the protrusion 7 into the opening 10a of the negative electrode current collector 10.

[0020] Furthermore, in order to sandwich the negative electrode collector 10 in the gap between the seating surface 9A of the protrusion 7 and the upper surface 6A of the fixed plate 6 and to reliably contact both the seating surface 9A and the upper surface 6A of the fixed plate 6, the thickness T1 of the negative electrode collector 10 is longer than the distance H0 between the seating surface 9A of the protrusion 7 and the upper surface 6A of the fixed plate 6, and the ratio of the thickness T1 of the negative electrode collector 10 to the distance H0 between the seating surface 9A of the protrusion 7 and the upper surface 6A of the fixed plate 6 is 8:7. Furthermore, if the distance H0 between the seating surface 9A of the protrusion 7 and the upper surface 6A of the fixed plate 6 is 88% or more and less than 100% of the thickness T1 of the negative electrode collector 10, the opening periphery of the negative electrode collector 10 contacts both the seating surface 9A of the protrusion 7 and the upper surface 6A of the fixed plate 6, and the negative electrode collector 10 is reliably fixed to the fixing member 5. As a result, the negative electrode current collector 10 is electrically connected to the can bottom 2C of the exterior can 2. If the distance H0 between the seating surface 9A of the protrusion 7 and the upper surface 6A of the fixing plate 6 is less than 88% of the thickness T1 of the negative electrode current collector 10, it becomes difficult to sandwich the peripheral portion of the opening of the negative electrode current collector 10 in the gap between the seating surface 9A of the protrusion 7 and the upper surface 6A of the fixing plate 6.

[0021] As described above, the diameter D0 of the shaft portion 8 of the fixing member 5, the maximum diameter D1 of the head portion 9, the distance H0 between the seat surface 9A and the upper surface 6A of the fixing plate 6, the thickness T1 of the negative electrode current collector 10, the diameter D2 of the opening 10a, and the diameter D S By defining this, the electrode body 3 is fixed to the outer can 2 via the negative electrode current collector 10 and the fixing member 5. As a result, the electrode body 3 is electrically connected to the outer can 2.

[0022] Next, a positive electrode current collector 14 is fixed to the other end of the electrode body 3, and the positive electrode plate 11 is electrically connected to the positive electrode current collector 14. A positive electrode lead 15 is attached to the positive electrode current collector 14. After the electrode body 3 is housed in the outer can 2, an alkaline electrolyte is poured into the outer can 2. The alkaline electrolyte is impregnated into the electrode body 3, and contributes to the electrochemical reaction between the positive electrode plate 11 and the negative electrode plate 12. The alkaline electrolyte is an aqueous solution containing KOH, NaOH, and LiOH.

[0023] The tip of the positive electrode lead 15 is welded to the inner surface of a circular conductive sealing body 4. The sealing body 4 has a gas vent hole 16 in the center, and a rubber valve body 17 is arranged on the outer surface so as to close the gas vent hole 16. The sealing body 4 is arranged at the opening end 2A of the outer can 2, and is fixed to the opening end 2A by crimping the opening end 2A of the outer can 2 via an insulating gasket 18 sandwiched between the outer periphery of the sealing body 4 and the inner periphery of the outer can 2. In this way, the gasket 18 and the sealing body 4 close the outer can 2, and electrically insulate the sealing body 4 from the outer can 2. A positive electrode terminal 19 is attached to the sealing body 4. The battery 1 is assembled as described above.

[0024] In this embodiment, the negative electrode current collector 10 attached to the electrode body 3 is fixed to the can bottom 2C of the outer can 2 using the fixing member 5 welded to the can bottom 2C, thereby electrically connecting the electrode body 3 to the outer can 2. This eliminates the need to insert a tool, such as a welding rod for resistance welding, into the hollow core portion S in order to fix the negative electrode current collector 10 to the can bottom 2C. In this way, when attaching the electrode body 3 to the can bottom 2C of the outer can 2, there is no contact between the hollow core portion S of the electrode body 3 and the tool, so that deterioration in quality of the electrode body 3 due to the attachment work can be suppressed.

[0025] In addition, since the circular fixing member 5 having the protrusion 7 formed by metal press working is resistance welded to the can bottom 2C, the protrusion 7 for fixing the negative electrode current collector 10 can be easily provided inside the outer can 2, rather than providing the protrusion 7 by processing the outer can 2 itself.

[0026] Next, a modified example of the fixing member 5 will be described with reference to FIG.

[0027] The fixing member 25 is made of a conductive metal, and as shown in Fig. 6, has a fixing plate 26 and a protrusion 27 that stands up from the center of the fixing plate 26. The fixing plate 26 has the same shape as the fixing plate 6, and its outer edge is welded to the can bottom 2C of the outer can 2 by resistance welding, electrically connecting the fixing member 25 to the outer can 2. The protrusion 27 has a shaft 28 that extends from the center of the fixing plate 26 in the axial direction of the battery 1. The tip of the shaft 28 forms an opening 28a, and a truncated cone-shaped locking portion 29 is formed on the periphery of the opening 28a. The truncated cone-shaped small diameter portion 29A of the locking portion 29 coincides with the opening 28a, and the truncated cone-shaped large diameter portion 29B of the locking portion 29 is closer to the upper surface 26A of the fixing plate 26 than the small diameter portion 29A. The surface surrounded by the large diameter portion 29B of the truncated cone serves as the seat surface 29B, and the negative electrode current collector 10 is sandwiched in the gap between the seat surface 29B and the upper surface 26A of the fixing plate 26, whereby the electrode body 3 fixed to the negative electrode current collector 10 is fixed to the exterior can 2 via the fixing member 25 and electrically connected. The shaft portion 28 has a cross-sectional diameter D 10 The height from the upper surface 26A of the fixed plate 26 to the seat surface is H 10 The cross section of the engaging portion 29 perpendicular to the axial direction, i.e., the diameter of the large diameter portion, is D 11 The maximum diameter D 11 is the diameter D of the cross section of the shaft 10 Longer.

[0028] When the opening 10a of the negative current collector 10 is aligned with the protrusion 27 of the fixing member 25 and the opening 10a is fitted into the protrusion 27, and the locking portion 29 of the protrusion 27 is passed through the opening 10a, the peripheral portion of the opening 10a of the negative current collector 10 can be sandwiched in the gap between the seat surface 29B and the upper surface 26A of the fixing plate 26, as shown in FIG. 7. As a result, the negative current collector 10 is fixed to the can bottom 2C by the fixing member 25. Therefore, the negative plate 12 is electrically connected to the outer can 2 via the negative current collector 10 and the fixing member 5. The locking portion 29 of the protrusion 27 inserted into the hollow core portion S is aligned with the diameter D of the large diameter portion 29B. 11 is the diameter D of the hollow core S S Since the protrusion 27 is shorter than the inner surface of the hollow core portion S, contact between the protrusion 27 and the inner surface of the hollow core portion S is avoided.

[0029] The shaft portion 28 and the locking portion 29 of the fixing member 25 of the modified example correspond to the shaft portion 8 and the head portion 9 of the fixing member 5 of the first embodiment, respectively. Therefore, the dimensional relationship between the corresponding members, i.e., the diameter D of the hollow core portion S of the electrode body 3, S The relationship between the diameter D2 and the thickness T1 of the opening 10a of the negative electrode current collector 10 is the same between the modified example and the first embodiment, and therefore a detailed description thereof will be omitted.

[0030] In the above embodiment, a configuration has been described in which a negative electrode current collector is fixed and electrically connected to the can bottom 2C of the outer can 2. However, depending on the configuration of the battery, the present invention can also be applied to a configuration in which a positive electrode current collector is fixed and electrically connected to the can bottom of the outer can.

[0031] The present invention can be applied to any type of battery, such as a primary battery or a secondary battery, in which an electrode assembly is formed by winding a positive electrode plate, a separator, and a negative electrode plate. [Explanation of symbols]

[0032] 1 battery 2 Outer can 3 Electrode body 5 Fixing material 7 Protrusion 10 Current collector 10a opening 11 Positive electrode plate 12 Negative plate 13 Separator

Claims

1. A battery in which an electrode assembly formed by winding a positive electrode plate and a negative electrode plate facing each other with a separator interposed therebetween into a cylindrical shape is housed in a bottomed cylindrical outer can, a current collector having an opening in the center and attached to one end of the electrode assembly in the axial direction; a conductive fixing member fixed to a bottom of the outer can; Equipped with the fixing member has a protrusion protruding toward the current collector, the opening of the current collector is pushed toward the protrusion to fix the current collector to the outer can, thereby electrically connecting the current collector to the outer can via the fixing member.

2. The electrode body has a cylindrical hollow core portion at its center, the hollow core portion penetrating from the one end to the other end along the axial direction, the protrusion has a shaft portion extending in the axial direction from a surface of the fixing member facing the current collector, and a head portion provided at a tip of the shaft portion and positioned within the hollow core portion, The battery in accordance with claim 1 , wherein the maximum diameter of the head portion is smaller than the diameter of a cross section of the hollow core portion perpendicular to the axial direction at one end of the electrode body.

3. The head portion has a head seat surface in contact with the current collector, 3. The battery in accordance with claim 2, wherein the maximum diameter of the head portion is larger than the diameter of the opening of the current collector, and the ratio of the diameter of the opening to the maximum diameter of the head portion is 88% or more.

4. The shaft portion of the fixing member is inserted through the opening, 4. The battery according to claim 2 or 3, wherein the thickness of the current collector is longer than the distance between the head seating surface of the protrusion and the opposing surface, and the ratio of the distance between the head seating surface and the opposing surface to the thickness of the current collector is 88% or more.

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