JP5651536B2 - Cylindrical secondary battery - Google Patents

Description

  The present invention relates to a cylindrical secondary battery, and more particularly to a cylindrical secondary battery having a connection member that connects one of positive and negative electrode plates of a power generation element and a battery can.

  A cylindrical secondary battery represented by a lithium secondary battery or the like has a power generation element in which a positive electrode plate and a negative electrode plate are wound around a shaft core via a separator in a battery container, and an electrolyte solution Infused and configured. The positive and negative electrode plates respectively have positive and negative active materials coated on both surfaces of the positive and negative metal foils. Each of the positive and negative metal foils has a number of tabs arranged at a predetermined pitch along one side edge in the longitudinal direction. The positive and negative tabs are formed along one side edge opposite to each other.

The tabs of the positive and negative electrode plates are wound around the outer circumference of a thin cylindrical current collector plate integrated with the winding shaft, respectively, and a large number of conductive leads are stacked on the current collector plate. Joined by ultrasonic welding or the like.
One of the positive and negative electrode plates is electrically connected to the battery can containing the power generation element at the bottom, and the other of the positive and negative electrode plates is connected to the battery can via a gasket (insulating member). It is electrically connected to the joined battery lid.

As a connection structure between one of the positive and negative electrode plates and the bottom of the battery can, a connecting lead plate having a strip-like elongated shape is extended from one end side of the current collector plate to the other end side through the center portion, A structure is known in which both ends of the connection lead plate are joined to a current collector plate and the center is joined to the bottom of a battery can by resistance welding or the like.
The connecting lead plate has a pair of flat portions bent in a direction rising from a central portion joined to the battery can and further bent in a direction parallel to the bottom portion of the battery can. The pair of flat portions 1 is joined to the peripheral edge of the current collector plate (see, for example, FIG. 4 of Patent Document 1).

Japanese Patent No. 3627645

  The cylindrical secondary battery described in Patent Document 1 has a structure in which both ends of a strip-like conductive lead plate are joined to a current collector plate. For this reason, the bonding strength with the current collector plate is large for an external force acting in the longitudinal direction, but is small for an external force acting in the direction perpendicular to the longitudinal direction, that is, the short direction. Therefore, when the cylindrical secondary battery receives an external force such as vibration or impact, the bonding may be peeled off.

A cylindrical secondary battery according to the present invention includes a power generation element in which positive and negative electrode plates are wound around an axis through a separator, and a current collector connected to one of the positive and negative electrode plates. A battery lead having a plate, a connecting lead plate joined to the current collecting plate, an opening in the upper portion, the power generating element, the current collecting plate and the connecting lead plate being accommodated, and an electrolyte injected therein A battery lid that closes the opening of the battery can and is fixed to the battery can via an insulating member, and the connecting lead plate uses a planar member that has a triangular deployed planar shape. In order to join the three current collector plate mounting portions to the current collector plate, each of the current collector plate mounting portions is formed to be refracted so as to include each vertex of the current collector plate. and at least one junction, to join the lead-plates to the battery can, before Has a battery can mount portion provided in a predetermined area of the planar member, wherein the connecting lead plate, a plane that contains the center of the axis in the region surrounded by the respective junction of the collector plate mounting portion It is arranged at a position.

According cylindrical secondary battery of the present invention, lead-plate is provided with three current collecting plate mounting portion having at least one bonding sites, respectively, the axial center in a region surrounded by each junction Arranged in the included plane position. Therefore, the connection between the connection lead plate and the current collector plate exhibits a high strength against an external force acting not only in one direction but also in a direction orthogonal to the one direction.
In addition, for the connection lead plate, a triangular plate member is used, and the current collector plate mounting portion is formed by bending each vertex thereof, so a large number of triangular materials for forming the connection lead plate are used. Can get at once. For this reason, sorting and production efficiency can be made high.

Sectional drawing which shows one Embodiment of the cylindrical secondary battery which concerns on this invention. FIG. 2 is an exploded perspective view of the cylindrical secondary battery shown in FIG. 1. The detail of the electric power generation element of FIG. 1, and the perspective view of the state which cut | disconnected a part. FIG. 2 is an enlarged external perspective view of the connection lead plate illustrated in FIG. 1. FIG. 5 is a development view of the connection lead plate illustrated in FIG. 4. FIG. 5 is a plan view for explaining a method of forming the connection lead plate shown in FIG. 4 from a base material. The top view which looked at the electric power generation unit illustrated by FIG. 2 from the downward direction. The top view which showed Embodiment 2 of the cylindrical secondary battery which concerns on this invention, and looked at the electric power generation unit from the downward direction. The top view which showed Embodiment 3 of the cylindrical secondary battery which concerns on this invention, and looked at the electric power generation unit from the downward direction. The top view which showed Embodiment 4 of the cylindrical secondary battery which concerns on this invention, and looked at the electric power generation unit from the downward direction.

--Embodiment 1-
[Overall structure]
Hereinafter, the cylindrical secondary battery of this invention is demonstrated with drawing.
FIG. 1 is an enlarged cross-sectional view showing an embodiment of a cylindrical secondary battery of the present invention, and FIG. 2 is an exploded perspective view of the cylindrical secondary battery shown in FIG.
The cylindrical secondary battery 1 is, for example, a lithium ion secondary battery. The cylindrical secondary battery 1 includes a battery case 4 including a cylindrical battery can 2 having a bottom and an upper opening, and a hat-type battery lid 3 that seals the top of the battery can 2. Inside the battery container 4, constituent members for power generation described below are accommodated, and a non-aqueous electrolyte 5 is injected.

In the cylindrical battery can 2, a groove 2 a protruding to the inside of the battery can 2 is formed on the opening 2 b provided on the upper end side.
A power generation element 10 is disposed at the center of the battery can 2. The power generation element 10 includes an elongated cylindrical shaft core 15 having a hollow portion along the axial direction, and a positive electrode plate and a negative electrode plate wound around the shaft core 15.

[Power generation element]
FIG. 3 is a perspective view showing the details of the structure of the power generation element 10, with a part cut away.
As shown in FIG. 3, the power generation element 10 has a structure in which a positive electrode plate 11, a negative electrode plate 12, and first and second separators 13 and 14 are wound around an axis 15.

  The shaft core 15 is formed of an insulating material such as PP (polypropylene) and has a hollow cylindrical shape. A first separator 13, a negative electrode plate 12, a second separator 14, and a positive electrode plate 11 are sequentially stacked on the shaft core 15 and wound. Inside the innermost negative electrode plate 12, the first separator 13 and the second separator 14 are wound several times (one turn in FIG. 3). The first separator 13 and the second separator 14 are formed of an insulating porous body.

  On the inner circumference (axial core) side, the negative electrode plate 12 extends from the positive electrode plate 11 to the axial core side. On the outer peripheral side, the negative electrode plate 12 extends to the outer peripheral side from the positive electrode plate 11. A second separator 14 extends on the outer periphery of the outermost negative electrode plate 12. The end of the second separator 14 on the outermost periphery is stopped with an adhesive tape 19 (see FIG. 2).

  The positive electrode plate 11 is formed of an aluminum foil and has a long shape. The positive electrode plate 11 includes a positive electrode metal foil 11a and a positive electrode processing portion 11b in which a positive electrode mixture is applied to both surfaces of the positive electrode metal foil 11a. The upper side edge extending in the longitudinal direction of the positive electrode metal foil 11a is a positive electrode mixture untreated portion 11c where the positive electrode mixture is not applied and the positive electrode metal foil 11a is exposed. In the positive electrode mixture untreated portion 11c, a large number of positive electrode tabs 16 protruding upward along the axis of the shaft core 15 are integrally formed at equal intervals.

The positive electrode mixture includes a positive electrode active material, a positive electrode conductive material, and a positive electrode binder. Examples of the positive electrode active material include lithium oxides such as cobalt, manganese, and nickel.
Examples of the positive electrode binder include polyvinylidene fluoride (PVDF) and fluororubber.

  Examples of the method for applying the positive electrode mixture to the positive electrode metal foil 11a include a roll coating method and a slit die coating method. A slurry obtained by kneading a dispersion solution in a positive electrode mixture is uniformly applied to both surfaces of an aluminum foil having a thickness of 20 μm, dried, pressed, and cut. An example of the coating thickness of the positive electrode mixture is about 40 μm on one side. When the positive electrode metal foil 11a is cut, the positive electrode tab 16 is integrally formed. All the positive electrode tabs 16 have substantially the same length.

  The negative electrode plate 12 includes a negative electrode metal foil 12a formed of a copper foil and having a long shape, and a negative electrode processing portion 12b in which a negative electrode mixture is applied to both surfaces of the negative electrode metal foil 12a. The lower side edge extending in the longitudinal direction of the negative electrode metal foil 12a is a negative electrode mixture untreated portion 12c where the negative electrode mixture is not applied and the copper foil is exposed. A large number of negative electrode tabs 17 extending in the direction opposite to the positive electrode tab 16 along the axis of the shaft core 15 are integrally formed at equal intervals in the negative electrode mixture untreated portion 12c.

  The negative electrode mixture includes a negative electrode active material, a negative electrode binder, and a thickener. An example of the negative electrode active material is graphite carbon.

Examples of the method for applying the negative electrode mixture to the negative electrode metal foil 12a include a roll coating method and a slit die coating method.
A slurry obtained by kneading a dispersion solvent in a negative electrode mixture is uniformly applied to both sides of a rolled copper foil having a thickness of 10 μm, dried, and then cut. An example of the coating thickness of the negative electrode mixture is about 40 μm on one side. When the negative electrode metal foil 12a is cut by pressing, the negative electrode tab 17 is integrally formed. All the negative electrode tabs 17 have substantially the same length.

The widths of the first and second separators 13 and 14 are larger than the widths of the positive electrode plate 11 and the negative electrode plate 12. The width of the negative electrode processing part 12 b of the negative electrode plate 12 is larger than the width of the positive electrode processing part 11 b of the positive electrode plate 11.
The width and length of the negative electrode processing unit 12b are made larger than the width and length of the positive electrode processing unit 11b, and the entire region of the positive electrode processing unit 11b is covered with the negative electrode processing unit 12b. In the case of a lithium ion secondary battery, lithium, which is a positive electrode active material, is ionized, penetrates the separator, and is occluded by the negative electrode active material. In this case, if the negative electrode active material is not formed on the negative electrode side and the negative electrode metal foil 12a is exposed, lithium is deposited on the negative electrode metal foil 12a, causing an internal short circuit. As described above, by covering the entire region of the positive electrode processing unit 11b with the negative electrode processing unit 12b, it is possible to prevent such an internal short circuit due to lithium deposition.

  The first separator 13 and the second separator 14 are each formed of, for example, a polyethylene porous film having a thickness of 40 μm.

  1 and 3, a hollow cylindrical shaft core 15 is formed with a groove 15a having a diameter larger than that of the hollow portion on the inner surface of the upper end portion in the axial direction (vertical direction in the drawing). A thin cylindrical positive electrode current collector plate 27 is press-fitted.

  The positive electrode current collector plate 27 is made of, for example, an aluminum-based metal, and has a disk-like base portion 27a and a lower portion that protrudes toward the shaft core 15 at the inner peripheral portion of the base portion 27a and press-fits into the inner surface of the shaft core 15 It has the cylinder part 27b and the upper cylinder part 27c which protrudes in the battery cover 3 side in an outer periphery. An opening 27d (see FIG. 2) for releasing gas generated inside the battery is formed in the base 27a of the positive electrode current collector plate 27.

All the positive electrode tabs 16 of the positive electrode metal foil 11 a are welded to the upper cylindrical portion 27 c of the positive electrode current collector plate 27.
The positive electrode tab 16 and the pressing member 28 of the positive electrode metal foil 11 a are welded to the outer periphery of the upper cylindrical portion 27 c of the positive electrode current collector plate 27. A number of positive electrode tabs 16 are brought into close contact with the outer periphery of the upper cylindrical portion 27c of the positive electrode current collector plate 27, and a pressing member 28 is wound around the outer periphery of the positive electrode tab 16 in a ring shape and temporarily fixed. In this state, ultrasonic welding is performed. Are joined together.

A step portion 15b having a small outer diameter is formed on the outer periphery of the lower end portion of the shaft core 15, and the negative electrode current collector plate 21 is press-fitted and fixed to the step portion 15b. The negative electrode current collector plate 21 is formed of, for example, a copper-based metal, and an opening 21b that is press-fitted into the step portion 15b of the shaft core 15 is formed in a disk-shaped base portion 21a. An outer peripheral cylindrical portion 21c that protrudes toward is formed.
An opening 21 d (see FIG. 2) for allowing the non-aqueous electrolyte 5 injected into the hollow shaft of the shaft core 15 to penetrate into the power generation element 10 is formed in the base 21 a of the negative electrode current collector plate 21.

All of the negative electrode tabs 17 of the negative electrode metal foil 12 a are joined to the outer peripheral cylindrical portion 21 c of the negative electrode current collector plate 21.
The negative electrode tab 17 and the pressing member 22 of the negative electrode metal foil 12 a are welded to the outer periphery of the outer peripheral cylindrical portion 21 c of the negative electrode current collector plate 21. A number of negative electrode tabs 17 are brought into close contact with the outer periphery of the outer peripheral cylindrical portion 21c of the negative electrode current collector plate 21, and the holding member 22 is wound around the outer periphery of the negative electrode tab 17 in a ring shape and temporarily fixed, and is welded in this state. .
A connection lead plate 50 is joined to the base portion 21a of the negative electrode current collector plate 21 by ultrasonic welding or the like. Details of the connection between the connection lead plate 50 and the negative electrode current collector plate 21 will be described later.
The connection lead plate 50 is joined to the bottom 2c of the iron battery can 2 by resistance welding or the like.

  Here, the opening 27 e formed in the positive electrode current collector plate 27 is for inserting an electrode rod (not shown) for welding the connection lead plate 50 to the battery can 2. The electrode rod is inserted into the hollow portion of the shaft core 15 through the opening 27e formed in the positive electrode current collector plate 27, and the connecting lead plate 50 is pressed against the inner surface of the bottom portion 2c of the battery can 2 at the tip thereof to perform resistance welding. The bottom surface of the battery can 2 connected to the negative electrode current collector plate 21 acts as one output terminal, and the electric power stored in the power generation element 10 can be taken out from the battery can 2.

  A large number of positive electrode tabs 16 are welded to the positive electrode current collector plate 27, and a large number of negative electrode tabs 17 are welded to the negative electrode current collector plate 21, whereby the positive electrode current collector plate 27, the negative electrode current collector plate 21 and the power generation element 10 are integrated. A unitized power generation unit 20 is configured (see FIG. 2). However, in FIG. 2, for convenience of illustration, the negative electrode current collector plate 21, the connection lead plate 50, and the pressing member 22 are illustrated separately from the power generation unit 20.

  A flexible connection member 33 formed by laminating a plurality of aluminum foils is joined to the upper surface of the base portion 27a of the positive electrode current collector plate 27 by welding one end thereof.

[Battery cover unit]
A battery lid unit 30 is disposed on the upper cylindrical portion 27 c of the positive electrode current collector plate 27. The battery lid unit 30 includes a ring-shaped insulating plate 34, a connecting plate 35 fitted in an opening 34a provided in the insulating plate 34, a diaphragm 37 welded to the connecting plate 35, and a diaphragm 37 by caulking and welding. The battery cover 3 is fixed.
The insulating plate 34 has a ring shape made of an insulating resin material having a circular opening 34 a and is placed on the upper cylindrical portion 27 c of the positive electrode current collector plate 27.

  The insulating plate 34 has an opening 34a (see FIG. 2) and a side portion 34b protruding downward. A connecting plate 35 is fitted in the opening 34 a of the insulating plate 34. The other end of the connection member 33 is welded and joined to the lower surface of the connection plate 35.

  The connection plate 35 is made of an aluminum-based metal and has a substantially dish shape that is substantially uniform except for the central portion and is bent to a slightly lower position on the central side. At the center of the connection plate 35, a thin dome-shaped projection 35a is formed, and a plurality of openings 35b (see FIG. 2) are formed around the projection 35a. The opening 35b has a function of releasing gas generated inside the battery.

  The protrusion 35 a of the connection plate 35 is joined to the bottom surface of the center portion of the diaphragm 37 by resistance welding or friction stir welding. The diaphragm 37 is formed of an aluminum-based metal, and has a circular cut 37 a centering on the center portion of the diaphragm 37. The cut 37a is formed by crushing the upper surface side into a V shape by pressing and thinning the remainder. The diaphragm 37 is provided for ensuring the safety of the battery, and has a function of cleaving at the cut 37a and releasing the internal gas when the internal pressure of the battery increases.

  The diaphragm 37 fixes the peripheral edge of the battery lid 3 at the peripheral edge. As shown in FIG. 2, the diaphragm 37 initially has a side wall 37 b erected vertically at the peripheral portion toward the battery lid 3 side. The battery lid 3 is accommodated in the side wall 37b, and the side wall 37b is bent and fixed to the upper surface side of the battery lid 3 by caulking.

  The battery lid 3 is made of iron such as carbon steel, and is nickel-plated on both front and back surfaces. Having a hat shape. An opening 3c is formed in the cylindrical portion 3b. The opening 3c is for releasing gas to the outside of the battery when the diaphragm 37 is cleaved by the gas pressure generated inside the battery. The battery lid 3 acts as one power output end, and the stored electric power can be taken out from the battery lid 3.

A gasket 43 made of an insulating member that covers the caulked portion between the diaphragm 37 and the battery lid 3 is provided. The gasket 43 is made of rubber, and is not intended to be limited, but one example of a preferable material is a fluorine-based resin.
As shown in FIG. 2, the gasket 43 initially has a shape having an outer peripheral wall portion 43 b that is formed on the peripheral side edge of the ring-shaped base portion 43 a so as to stand substantially vertically toward the upper direction. ing.

  Then, the outer peripheral wall 43b of the gasket 43 is bent together with the battery can 2 by pressing or the like, and the diaphragm 37 and the battery lid 3 are crimped by the base 43a and the outer peripheral wall 43b so as to be pressed in the axial direction. Thereby, the battery lid unit 30 in which the battery lid 3, the diaphragm 37, the insulating plate 34 and the connection plate 35 are integrally formed is fixed to the battery can 2 via the gasket 43.

  A predetermined amount of non-aqueous electrolyte 5 is injected into the battery can 2. As an example of the nonaqueous electrolytic solution 5, a solution in which a lithium salt is dissolved in a carbonate-based solvent is raised.

[Connecting structure of connecting lead plate]
Next, a joint structure between the connection lead plate 50 and the negative electrode current collector plate 21 will be described.
4 is an enlarged perspective view of the connection lead plate shown in FIG. 1, and FIG. 5 is a development view of the connection lead plate shown in FIG.
The connecting lead plate 50 is made of nickel-based metal or copper-based metal, and the material has a regular triangular plane shape.

The connecting lead plate 50 includes a battery can mounting portion 51 having a hexagonal planar shape formed in the center portion, and three current collector plate mounting portions 52 formed in the vicinity of each top portion.
The battery can mounting portion 51 has a joint portion 51a that is joined to the bottom 2c of the battery can 2 by resistance welding or the like.
Each of the current collector plate attachment portions 52 is formed in parallel with the battery can attachment portion 51 and has one joint portion 52a that is joined to the peripheral edge portion of the base portion 21a of the negative electrode current collector plate 21 by ultrasonic welding or the like.

  In order to form the connection lead plate 50, first, a regular triangular nickel metal plate is bent at a right angle or inclined with respect to one surface of the metal plate at a bent portion 50a in the vicinity of each apex (mountain fold). Then, the battery can mounting part 51 is formed at the center. Next, further bending (valley fold) is performed at the bent portion 50b on the distal end side to form three current collector plate mounting portions 52 parallel to the upper surface of the metal plate. Examples of the processing method for forming the connection lead plate 50 in this way include deep drawing and bending.

FIG. 6 is a plan view for explaining a method of forming the connection lead plate 50 from a metal plate as a base material.
The nickel metal base material 60 is sized to form a large number of connection lead plates 50.
Since the material 50S of the connection lead plate 50 has a triangular shape, it is alternately arranged with one side as a boundary surface and up and down or left and right.
Therefore, as shown in FIG. 6, they are arranged without forming any gap between the raw materials 50 </ b> S of the adjacent connection lead plates 50 except for the side end portions of the base material. That is, as illustrated in FIG. 6, by cutting along each side of the material 50 </ b> S, a large number of triangular materials 50 </ b> S for forming the connection lead plate 50 can be obtained at one time. For this reason, sorting and production efficiency can be made high.
The method of forming the connection lead plate 50 from each metal plate is as described above.

FIG. 7 is a bottom view from below of the power generation unit 20 illustrated in FIG. 2.
Each of the three current collecting plate attachment portions 52a1 to 52a3 of the connection lead plate 50 has one joining portion 52a. Each joining portion 52 a is joined to the base 21 a of the negative electrode current collector plate 21.
The center of gravity of the connection lead plate 50 is located coaxially with the center O of the shaft core 15.

In FIG. 7, a straight line connecting the center of the joint portion 52 a 1 and the center O of the shaft core 15 is defined as a y-axis, and a straight line perpendicular to the y-axis passing through the center O of the shaft core 15 is defined as an x-axis. When the joining part 52a1 is located at the boundary between the first quadrant I and the second quadrant II, the connecting lead plate 50 is an equilateral triangle, so the joining part 52a2 and the joining part 52a3 are respectively in the third quadrant III, Located in the fourth quadrant IV.
And the connection lead board 50 is arrange | positioned in the plane position where the center O of the axial center 15 is contained in the triangular area | region (area | region shown with a dashed-two dotted line in FIG. 7) enclosed by each joining site | part 52a1-52a3. .

In the state illustrated in FIG. 7, the joint portions 52 a 1 to 52 a 3 are arranged at the same interval with respect to the center O of the shaft core 15. When an external force is applied to the cylindrical secondary battery 1, considering the case where the coordinates of FIG. 7 are rotated and the direction in which the external force is applied corresponds to the x-axis direction, the joint portions 52 a 1 to 52 a 3 are respectively connected to the x-axis. In the direction and the y-axis direction. As described above, since the joint portions 52a1 to 52a3 are two-dimensionally arranged, the external force acting from an arbitrary direction is compared with the conventional structure in which the joint portions are arranged one-dimensionally (straight). This increases the bonding strength.
As described above, according to the embodiment of the present invention, when the cylindrical secondary battery 1 receives an external force such as vibration or impact, the bonding strength can be improved regardless of the direction in which the external force acts. it can.

  In the above embodiment, the connection lead plate 50 is exemplified as a regular triangle in plan shape. However, the planar shape of the connection lead plate 50 may be an isosceles triangle or an unequal triangle. However, the welded portion needs to be located at the boundary between three different quadrants or quadrants in the plane coordinates composed of four quadrants with the center O of the axis as the origin. In other words, it is necessary to arrange so that the center O of the shaft core is included in the region surrounded by the joint portions 52a1 to 52a3.

As described above, in the embodiment of the cylindrical secondary battery of the present invention, the connection lead plate 50 welded to the negative electrode current collector plate 21 has a triangular shape in plan view, and the battery can mounting portion 51 is provided at the center. At the same time, three current collector plate mounting portions 52 are provided in the vicinity of each top portion. Then, the joint portions 52a of the three current collector plate attachment portions 52 are positioned at different quadrants or quadrant boundaries in the plane coordinates with the center O of the shaft core 15 as the origin.
For this reason, when the cylindrical secondary battery 1 receives external force such as vibration or impact, the reliability of joining of the negative electrode current collector plate 21 and the connection lead plate 50 is improved regardless of the direction in which the external force acts. can do.

  In the above-described embodiment, the connection lead plate 50 has the three joint portions 52a. For this reason, internal resistance can be reduced compared with the conventional structure where a welding site | part is a strip-shaped both ends, ie, the welding site | part is two.

  In the above-described embodiment, the connection lead plate 50 has the center of gravity positioned coaxially with the center O of the shaft core 15. For this reason, external forces such as vibrations and impacts act on the three current collector plate attachment portions 52 and the joint portion 52a on average, and the breaking strength is made uniform.

In the above embodiment, the connection lead plate 50 is exemplified as a regular triangle or an isosceles triangle in the material 50S before processing. For this reason, by cutting out the material 50S of the connection lead plate 50 along each of the three sides, a large number of triangular materials 50S can be obtained from one metal base material. Production efficiency can be increased.
In the above-described embodiment, the connection lead plate 50 is exemplified as including the three current collector plate attachment portions 52 each having one joining portion 52a1 (52a2, 52a3). However, the current collector plate mounting portions 52 may be four or more.
Next, such an embodiment is shown.

--Embodiment 2-
FIG. 8 shows the second embodiment, and is a plan view from the bottom surface side of the power generation unit 20.
The connecting lead plate 50 </ b> A has a battery can mounting portion 51 having an octagonal planar shape at the center and four current collecting plate mounting portions 52.
Each of the current collector plate mounting portions 52 is formed by raising every other side of the battery can mounting portion 51 and bending the battery can mounting portion 51 in parallel with the battery can mounting portion 51 on the tip side. .
Each of the current collector plate mounting portions 52 has one joint portion 52a1 to 52a4.
The center of gravity of the connection lead plate 50 </ b> A is located coaxially with the center O of the shaft core 15.

The center of the joint part 52a1, the center O of the shaft core 15, and the center of the joint part 52a3 are located on the same straight line. The center of the joint part 52a2, the center O of the shaft core 15 and the center of the joint part 52a4 are located on the same straight line, and orthogonal to the straight line connecting the center of the joint part 52a1, the center O of the shaft core 15 and the center of the joint part 52a3. To do.
In FIG. 8, the straight line connecting the center O of the shaft core 15 and the center O and the center of the joint part 52a1 is located at the boundary between the first quadrant I and the second quadrant II, and the center O and the joint part 52a3. It is assumed that a straight line connecting the centers is located at the boundary between the third quadrant III and the fourth quadrant IV. In this case, the joint part 52a2 is located at the boundary between the second quadrant II and the third quadrant III, and the joint part 52a4 is located at the boundary between the first quadrant I and the fourth quadrant IV.
The connection lead plate 50A is disposed at a planar position where the center O of the axial center is included in a region (region indicated by a two-dot chain line in FIG. 8) surrounded by the joint portions 52a1 to 52a4.

Also in the case illustrated in FIG. 8, as in the case illustrated in FIG. 7, the joint portions 52 a 1 to 52 a 4 are two-dimensionally arranged with respect to the external force acting on the cylindrical secondary battery 1. Compared with a conventional structure arranged in a one-dimensional (straight) manner, the bonding strength is increased with respect to an external force acting from an arbitrary direction.
As described above, also in the second embodiment of the present invention, when the cylindrical secondary battery 1 receives external force such as vibration or impact, the bonding strength by the bonding portions 52a1 to 52a4 is obtained regardless of the direction in which the external force acts. Can be improved.

  Thus, in the second embodiment, as in the first embodiment, when the cylindrical secondary battery 1 receives an external force such as vibration or impact, the negative electrode current collector plate is independent of the direction in which the external force acts. The reliability of joining between 21 and the connecting lead plate 50A can be improved. Moreover, in the second embodiment, since the joint portions 52a1 and 52a3 and the joint portions 52a2 and 52a4 are located at the same distance from the center O of the shaft core 15, the proof stress in the direction in which the external force acts is equivalent, and the reliability is further increased. Improves.

  In the first and second embodiments, each current collector plate mounting portion 52 is exemplified as a structure having one joining portion 52a. However, it can also be set as the structure which has the some junction site | part 52a1-52a3 or 52a1-52a4 in the one current collecting plate attaching part 52. FIG. Next, such an embodiment is shown.

--Embodiment 3-
FIG. 9 shows the third embodiment and is a plan view from the bottom side of the power generation unit 20.
The connection lead plate 50B has a battery can mounting part 51 having a substantially trapezoidal planar shape at the center and two current collector mounting parts 52 and 53.
One collector plate mounting portion 52 is raised so that the short side of the pair of parallel sides of the battery can mounting portion 51 is raised, and is further bent parallel to the battery can mounting portion 51 on the tip side. Is formed. The current collector mounting part 52 has a triangular planar shape.
The other current collector plate mounting portion 53 is raised so that the long side of the pair of parallel sides of the battery can mounting portion 51 rises, and is further bent parallel to the battery can mounting portion 51 on the tip side. Is formed. In this case, the current collector plate attachment portion 53 has a rectangular planar shape, and the long side thereof is the same length as the long side of the battery can attachment portion 51.
The center of gravity of the connection lead plate 50B is located coaxially with the center O of the shaft core 15.

One current collector mounting portion 52 has one joint portion 52a1.
The other current collector plate attachment portion 53 has two joint portions 52a2 and 52a3. The joint portions 52a2 and 52a3 are set at symmetrical positions with respect to the center O of the shaft core 15.
In FIG. 9, when the center O of the shaft core 15 is the origin, and the straight line connecting the joint part 52a1 and the center O is located at the boundary between the first quadrant I and the second quadrant II, the joint part 52a2 and the joint part 52a3 is located in the third quadrant III and the fourth quadrant IV, respectively.
The connection lead plate 50B is disposed at a planar position where the center O of the shaft core is included in a region (region indicated by a two-dot chain line in FIG. 9) surrounded by the joint portions 52a1 to 52a3.

Also in the case illustrated in FIG. 9, as in the case illustrated in FIGS. 7 and 8, the joint portions 52 a 1 to 52 a 3 are two-dimensionally arranged with respect to the external force acting on the cylindrical secondary battery 1. Therefore, compared with the conventional structure arrange | positioned in one dimension (straight line), joining strength becomes large with respect to the external force which acts from arbitrary directions.
Thus, also in Embodiment 3 of the present invention, when the cylindrical secondary battery 1 receives external force such as vibration or impact, the bonding strength by the bonding parts 52a1 to 52a3 is obtained regardless of the direction in which the external force acts. Can be improved.
In FIG. 9, the current collector plate attachment portion 52 is exemplified as a configuration having one joint portion 52 a 1, but the current collector plate attachment portion 52 may also have a plurality of joint portions 52 a 1. Further, three or more current collector plate attachment portions 52 may be formed.

In the first to third embodiments, the shaft core 15 is not positioned on any straight line connecting the adjacent joint portions 52a but is spaced apart from all the straight lines.
However, the shaft core 15 may be arranged on any straight line connecting the adjacent joint portions 52a. Next, such an embodiment is shown.

Embodiment 4
FIG. 10 is a plan view from the bottom surface side of the power generation unit 20 according to the fourth embodiment.
The connection lead plate 50 </ b> C includes a battery can mounting portion 51 having a rectangular planar shape at the center, one current collecting plate mounting portion 52, and a pair of current collecting plate mounting portions 53.
The current collector plate mounting portion 52 is formed by being raised from one side of the pair of long sides of the battery can mounting portion 51 and further bent so as to be parallel to the battery can mounting portion 51 on the tip side. is there.
The pair of current collector plate mounting portions 53 are formed from both sides of the short side of the battery can mounting portion 51, and are bent so as to be parallel to the battery can mounting portion 51 on the distal end side. . In this case, each current collector mounting portion 53 has a rectangular planar shape, and the width thereof is the same as the width of the battery can mounting portion 51.
The current collector plate attachment portions 52 and 53 each have one joint portion 52a1 to 52a3.

In FIG. 10, when the center O of the axis 15 is the origin and the straight line connecting the center of the joint part 52a1 and the center O is located at the boundary between the first quadrant I and the second quadrant II, the joint part 52a2 is , Located at the boundary between the second quadrant II and the third quadrant III. Further, the joint portion 52a3 is located at the boundary between the first quadrant I and the fourth quadrant IV.
That is, the center of the joint part 52a2, the center O of the shaft core 15, and the center of the joint part 52a3 are positioned on a straight line. Also in this case, the connection lead plate 50C is disposed at a planar position where the center O of the shaft core is included in a triangular region (region indicated by a two-dot chain line in FIG. 10) surrounded by the joint portions 52a1 to 52a3. Yes.

Even in the case illustrated in FIG. 10, the joint portions 52 a 1 to 52 a 3 are two-dimensionally arranged with respect to the external force acting on the cylindrical secondary battery 1, and thus are arranged one-dimensionally (straight). Compared to the conventional structure, the bonding strength is increased with respect to an external force acting from an arbitrary direction.
Thus, also in Embodiment 4 of the present invention, when the cylindrical secondary battery 1 receives an external force such as vibration or impact, the bonding strength by the bonding portions 52a1 to 52a3 is obtained regardless of the direction in which the external force acts. Can be improved.

As described above, in each of the above embodiments, the connection lead plates 50, 50A, 50B, and 50C (hereinafter, representatively referred to as “50”) welded to the negative electrode current collector plate 21 have three or more joint portions. 52a was provided. And the connection lead board 50 is arrange | positioned in the plane position containing the center O of the axial center 15 in the area | region enclosed by each joining site | part 52a1-52a3 (52a4).
For this reason, even when the cylindrical secondary battery 1 receives external force such as vibration or impact, the bonding strength by the bonding portions 52a1 to 52a3 (52a4) can be improved regardless of the direction in which the external force acts.

  In each of the above embodiments, the connection lead plate 50 has three or more joint portions 52a. For this reason, internal resistance can be reduced compared with the conventional structure which has a welding site | part at both ends of a strip shape, ie, two.

  In the above embodiment, the connection lead plate 50 is provided so that the center of gravity thereof is positioned coaxially with the center O of the shaft core 15. For this reason, external forces such as vibrations and impacts act on the three current collector plate attachment portions 52 and the joint portion 52a on average, and the breaking strength is made uniform.

In addition, in the said embodiment, the case of the lithium ion cylindrical secondary battery was demonstrated. However, the present invention can also be applied to a cylindrical secondary battery using a water-soluble electrolyte such as a nickel metal hydride battery, a nickel cadmium battery, or a lead storage battery.
It can also be applied to a cylindrical lithium ion capacitor.

  In each said embodiment, it illustrated as a structure which connects the negative electrode plate 12 of the electric power generation element 10 to the battery can 2. FIG. However, the present invention can also be applied when the positive electrode plate 11 of the power generation element 10 is connected to the battery can 2.

  In each of the above embodiments, the connection lead plate 50 is exemplified as a structure having a plurality of current collector plate mounting portions 52. However, the current collector plate attachment portion 52 may be formed as a single portion that is bent around the outer periphery of the battery can attachment portion 51.

  In addition, the cylindrical secondary battery of the present invention can be applied with various modifications within the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Cylindrical secondary battery 2 Battery can 3 Battery cover 4 Battery container 10 Power generation element 11 Positive electrode plate 12 Negative electrode plate 15 Core core 21 Negative electrode current collecting plate 27 Positive electrode current collecting plate 50, 50A, 50B, 50C Connection lead plate 50a Bending Part 51 Battery can attachment part 52, 53 Current collector attachment part 52a, 52a1-52a4 Joining part 60 Base material

Claims (3)

A power generation element in which positive and negative electrode plates are wound around a shaft core via a separator;
A current collector connected to one of the positive and negative electrode plates;
A connection lead plate joined to the current collector plate;
A battery can having an opening at the top, housing the power generation element, the current collector plate and the connection lead plate, and injecting an electrolyte;
A battery lid that closes an opening of the battery can and is fixed to the battery can via an insulating member;
The connection lead plate is
Three current collector plate mounting portions formed by refracting so as to include each apex of the triangle, using a planar member whose developed planar shape is a triangle,
In order to join the three current collector plate attachment portions to the current collector plate, at least one joining portion formed in each of the current collector plate attachment portions;
To join the lead-plates to the battery can have a battery can mount portion provided in a predetermined area of said planar member,
The cylindrical rechargeable battery, wherein the connection lead plate is arranged at a planar position including a center of the shaft core in a region surrounded by the joint portions of the current collector plate mounting portion. 2. The cylindrical secondary battery according to claim 1 , wherein a center of gravity of the connection lead plate is located coaxially with a center of the shaft core. 3. 3. The cylindrical secondary battery according to claim 1, wherein the connecting lead plate is joined to the current collecting plate connected to the negative electrode plate.

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