JP4538857B2 - Cylindrical battery, method for manufacturing the same, and spot welding electrode for battery current collector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cylindrical battery, a manufacturing method thereof, and a spot welding electrode of a battery current collector.
[0002]
[Prior art]
Conventionally, a cylindrical battery described in Japanese Utility Model Publication No. 60-33572 is known. In this cylindrical battery, as shown in FIG. 8, an electrode body 2 is sealed in a bottomed cylindrical case 1. The electrode body is formed in an air-core cylindrical shape by winding the positive electrode plate 2a and the negative electrode plate 2b with the separator 2c interposed therebetween. The current collector 3 and the negative electrode plate 2b are connected to the lower negative electrode current collector 4 respectively. Of these, a U-shaped case connection piece 4a is cut out at the center of the negative electrode current collector 4, and the case connection piece 4a is welded to the case 1 so that the negative electrode plate 2b and the case are connected. 1 is connected through a negative electrode current collector 4.
[0003]
[Problems to be solved by the invention]
By the way, since this type of electrode body 2 is formed by winding an electrode plate, the electrode area increases toward the outer peripheral side of the electrode body 2. However, since the case connecting piece 4a is cut out from the vicinity of the center of the negative electrode current collector 4, current collection cannot be performed directly from the outer peripheral side where the electrode density is high, and there is a problem that current collection efficiency is not good. It was.
[0004]
Further, in the cylindrical battery having the above structure, spot welding is performed as follows in order to connect the case connecting piece 4a of the negative electrode current collector 4 to the case 1.
For this spot welding, a spot welding electrode 5 as shown in FIG. 9 is used. The spot welding electrode 5 has a tip portion of a round bar-like main body portion 5a formed in a taper shape, and its tip end is set as an axial center position of the main body portion 5a, which is a welding portion 5b.
In order to perform spot welding, first, the case 1 is placed on the electrode base 6 for spot welding, and then the electrode body 2 provided with the negative electrode current collector 4 is inserted into the case 1. The case connecting piece 4a of the negative electrode current collector 4 is brought into contact with 1a. Subsequently, the spot welding electrode 5 is inserted into the air core portion 7 of the electrode body 2, and the case connection piece 4 a is sandwiched between the welding portion 5 b and the bottom portion 1 a of the case 1. The case connecting piece 4 a and the bottom 1 a of the case 1 can be welded by passing a welding current between the spot welding electrode 5 and the electrode base 6.
[0005]
Conventionally, welding as described above has been performed only once. However, in recent years, depending on the application, a large output may be required. When a large current flows through the connection part of the case and the current collector, if there is only one welded part between the current collector and the case, current concentration may occur in the welded part and resistance loss may occur. There was a problem that the sex was not enough.
In order to cope with such a situation, it is conceivable to perform welding at a plurality of locations. However, the spot welding electrode 5 is placed in the air core portion 7 of the electrode body 2 in a state where the spot welding electrode 5 is inserted. Since there is not enough room to shift in the direction, it is difficult to change the position of the spot welding electrode 5 in the air core portion 7 and perform welding at a plurality of locations.
[0006]
The present invention aims to solve the above problems.
[0007]
[Means for Solving the Problems]
As means for achieving the above object, the invention of claim 1 is capable of accommodating an electrode body in which a positive electrode plate and a negative electrode plate are wound with a separator sandwiched between both electrode plates, and the electrode body. In a cylindrical battery comprising a bottomed cylindrical case, and a current collector connected to the electrode body and connected to one of the electrode plates, the case,
The current collector includes a current collector body portion addressed over substantially the entire end face of the electrode body, and a lead piece extending from an outer peripheral edge thereof and connected to a bottom portion of the case, and the current collector body The portion is provided with a slit extending in the radial direction, and a side along the radial direction of the slit is bent toward the electrode body side to be a burr portion connected to the electrode body. .
The invention of claim 2 is characterized in that, in the invention of claim 1, the current collector includes a plurality of the lead pieces.
[0008]
The invention according to claim 3 is an electrode body in which a positive electrode plate and a negative electrode plate are wound in an air-core shape with a separator sandwiched between both electrode plates, and a bottomed cylindrical case that can accommodate the electrode body; A method of manufacturing a cylindrical battery having a current collector addressed to an end face of the electrode body and connected to one of the electrode plates and welded to a bottom portion of the case, A spot welding electrode for welding the current collector and the case can be inserted into the air core portion formed in the body, and the axial center of the electrode body is provided at the tip of the spot welding electrode. A welded portion is formed at an eccentric position from the base, and after the primary welding is performed with the current collector sandwiched between the welded portion and the bottom of the case, the spot welding electrode is rotated, and the welding is performed. When the secondary welding is performed with the current collector sandwiched between the case and the case Furnace has a feature.
The invention of claim 4 is characterized in that, in the invention of claim 3, the welding power in the secondary welding is made higher than that in the primary welding.
[0009]
The invention according to claim 5 is an electrode body in which a positive electrode plate and a negative electrode plate are wound in an air-core shape with a separator sandwiched between both electrode plates, and a bottomed cylindrical case that can accommodate the electrode body, In the cylindrical battery which is addressed to the end face of the electrode body and is connected to one of the electrode plates and is welded to the bottom of the case, the current collector is spot welded to the bottom of the case Spot welding electrode, comprising: a shaft-type electrode body inserted into an air core portion of the electrode body; and a weld portion formed at the tip thereof, wherein the weld portion is eccentric from the axis of the electrode body. It is characterized by the configuration provided at the position.
[0010]
[Action and effect of the invention]
<Invention of Claim 1>
The current collector body is connected in a state of being addressed to substantially the entire end face of the electrode body, and a lead piece extending from the outer peripheral edge of the current collector body is connected to the bottom of the case. Here, since the electrode body is formed by winding an electrode plate, the electrode area increases toward the outer periphery, and the lead piece can be directly collected from the outer periphery. Thereby, the current collection efficiency of a cylindrical battery can be improved.
<Invention of Claim 2>
By forming a plurality of lead pieces, the current collector body and the case can be connected via a parallel circuit, so that current concentration and resistance loss can be suppressed as much as possible.
[0011]
<Invention of Claim 3 and Claim 5>
To weld the current collector and the case, after connecting the current collector to the end face of the electrode body, the electrode body is accommodated in the case, and the current collector and the bottom of the case are brought into contact with the electrode body. A spot welding electrode is inserted into the formed air core. Primary welding is performed with a current collector sandwiched between the welded portion of the spot welding electrode and the bottom of the case. Thereafter, the spot welding electrode is rotated. Since the welded part of this spot welding electrode is formed at a position deviated from the axis of the electrode body, the position of the welded part can be adjusted by rotating the spot welding electrode by a predetermined angle from the welding location after the primary welding. Alternatively, secondary welding can be performed. Thereby, since welding can be performed in two places, the contact reliability of a collector and a case can be improved. Furthermore, current concentration can be prevented and the occurrence of resistance loss can be suppressed as compared with the case where welding is performed only at one location.
[0012]
<Invention of Claim 4>
When secondary welding is performed after the current collector and the case are well welded by the primary welding, some of the current passes through the welded portion by the primary welding without passing through the portion to be welded. For this reason, although the welding state by secondary welding may become inferior, the welding state of secondary welding can be made favorable by raising the welding electric power at the time of this secondary welding.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
<First Embodiment>
A first embodiment of the present invention will be described with reference to FIGS. In this embodiment, the case where the present invention is applied to a cylindrical nickel-hydrogen secondary battery used in an electric vehicle is shown.
As shown in FIG. 1, the cylindrical battery 10 includes an electrode body 15 housed in a case 11, and a positive electrode plate 16 and a negative electrode plate 17 that form the electrode body 15 include a positive electrode current collector 20 and a negative electrode current collector. It is configured by being connected to the positive electrode 28 and the negative electrode 12 through the electric body 30, respectively.
[0014]
The case 11 is made of nickel-plated iron and also serves as the negative electrode 12, and is formed in a cylindrical shape having a bottom portion 13. In the vicinity of the upper end of the case 11, an annular protrusion 14 that protrudes inward is provided by squeezing from the outer peripheral side, and the upper surface is open. The electrode body 15 is formed by winding the positive electrode plate 16 upward and the negative electrode plate 17 downward while sandwiching the separator 18 between the two electrode plates 16, 17. Is formed. The positive electrode plate 16 is made of a nickel-plated belt-shaped perforated steel sheet obtained by sintering nickel powder and impregnated with nickel hydroxide. The negative electrode plate 17 is a nickel-plated belt-shaped perforated steel sheet. An alloy powder paste is applied and dried. A non-woven fabric made of polyolefin is used for the separator 18. A predetermined electrolytic solution (not shown) mainly composed of potassium hydroxide is permeated into the electrode body 15.
[0015]
A positive electrode current collector 20 is attached to the upper end surface of the electrode body 15 by welding. In the positive electrode current collector 20, for example, a pure nickel plate cut into a disk shape by pressing is annealed, and a central hole 21 is provided in the central portion. The connecting piece 22 is provided to extend upward.
[0016]
A sealing plate 23 whose outer peripheral portion is covered with an insulating packing 24 is sandwiched between the upper end portion of the case 11 and the annular protrusion 14. The sealing plate 23 is formed, for example, from an iron plate into a disk shape by pressing, and is plated with nickel, and a connection body 25 is provided on the back surface. The connection body 25 has a lower positive electrode. A connection protrusion 26 that can be connected to the connection piece 22 of the current collector 20 is extended. Further, a cap 27 that forms the positive electrode 28 is provided at the center of the upper surface of the sealing plate 23.
[0017]
A negative electrode current collector 30 is attached to the lower end surface of the electrode body 15 by welding. As shown in FIG. 2, the negative electrode current collector 30 is formed by, for example, subjecting a pure nickel plate cut out by press working to an annealing process to form a disk-shaped current collector main body 31. A central hole 32 is provided through the central portion of the current collecting main body 31, and opening slits 33 are provided on the outer peripheral edge at substantially equal angular intervals so as to open outward. .
[0018]
Among these opening slits 33, lead pieces 34 are provided to extend outward from the outer peripheral edge of the current collector main body 31 between predetermined adjacent opening slits 33, and can be folded back from the root portion to the center side. It is said that. Since the root portion is provided with relatively short slits 35 located on both sides of the lead piece 34, the folding operation is facilitated. The length of the lead piece 34 is set to a length that can sufficiently cover the center hole 32 in a folded state, and a portion that covers the center hole 32 is a contact portion 36. As shown in FIG. 1, the contact portion 36 comes into contact with the bottom portion 13 of the case 11 in the case 11, and in detail, is welded to the bottom portion 13 of the case 11 by a spot welding electrode 40 described later. It is like that.
[0019]
In addition, rectangular slits 37 are provided at four positions at substantially equal angular intervals at positions shifted by about 45 degrees from the opening slit 33. The sides along the radial direction of the opening slit 33 and the slit 37 are bent on the surface side opposite to the side on which the lead piece 34 is folded back, so that a burr 38 is projected. The burr 38 is connected to the negative electrode plate 17 at the lower end surface of the electrode body 15.
[0020]
As shown in FIG. 4, the spot welding electrode 40 is composed of a round bar-shaped electrode body 41 and a welded portion 42 at the tip thereof. Specifically, the distal end portion of the electrode body 41 is formed in a tapered shape, and the distal end thereof is a position eccentric from the axis of the electrode body 41, and this is the welded portion 42. The upper part of the electrode body 41 is connected to a welding device (not shown), and a welding current can be passed in a state in which the welding part 42 at the tip of the electrode body 41 is close to the electrode base 43 for spot welding. It is said that. Further, the diameter of the electrode body 41 is slightly smaller than the diameter of the air core portion 19 of the electrode body 15.
[0021]
The present embodiment has the above structure, and the assembly procedure will be described next.
First, after placing the case 11 on the electrode table 43, as shown in FIG. 3, the positive electrode current collector 20 and the negative electrode current collector 30 were welded to the upper and lower end faces of the electrode body 15, respectively. The case 11 is inserted downward from the open portion. At this time, the lead piece 34 of the negative electrode current collector 30 is folded back toward the center while being bent downward from the root portion, and the contact portion 36 is disposed so as to cover the center hole 32. When the electrode body 15 is inserted into the case 11, the contact portion 36 is brought into contact with the bottom portion 13 of the case 11.
[0022]
Subsequently, as shown in FIG. 4, the spot welding electrode 40 is inserted into the air core portion 19 of the electrode body 15 from above. The spot welding electrode 40 that has passed through the air core portion 19 passes through the center hole 32 of the negative electrode current collector 30, and the welding portion 42 that forms the tip abuts against the contact portion 36 of the lead piece 34. Insertion is stopped. As a result, the contact portion 36 of the lead piece 34 is sandwiched between the weld portion 42 of the spot welding electrode 40 and the bottom portion 13 of the case 11.
[0023]
Then, by passing a welding current between the spot welding electrode 40 and the electrode base 43, the contact portion 36 of the lead piece 34 and the bottom portion 13 of the case 11 are welded as shown in FIG. This is the primary welding, and the welded portion is the primary welding spot 50. By this primary welding, the negative electrode current collector 30 and the case 11 forming the negative electrode 12 are connected. The value of the welding power at this time is controlled to a value that allows the primary welding to be performed satisfactorily.
[0024]
After the primary welding, the spot welding electrode 40 is rotated by a predetermined angle in the direction shown by the arrow A in FIG. Thereby, the welding part 42 provided in the position eccentric from the axial center of the electrode main body 41 is in the position different from the primary welding location 50 in the contact part 36 of the lead piece 34, as shown in FIG. The contact portion 36 is again sandwiched between the bottom portion 13 of the case 11.
[0025]
By flowing a welding current in this state, secondary welding is performed, and the welded portion is set as a secondary welding location 51. The welding power at the time of performing the secondary welding is set to be larger than the welding power at the time of the primary welding that has already been performed. The magnitude of the welding voltage at this time is such that when the primary welding is performed satisfactorily, some of the welding current that flows during the secondary welding passes through the primary welding point 50 to the electrode base 43. Even if it flows in the direction, the current can be sufficiently large to obtain the current necessary for performing the secondary welding satisfactorily.
[0026]
Thus, since welding is performed at two locations, even if the primary welding is not performed well, the primary welding can be covered by the secondary welding, and welding defects can be prevented as much as possible. it can. Furthermore, if welding is performed well twice, even when a large current flows after the battery is assembled, the current concentration on the welded portion can be suppressed as much as possible, and the occurrence of resistance loss can be suppressed.
[0027]
Further, the lead piece 34 of the negative electrode current collector 30 is provided so as to extend from the outer peripheral edge of the current collector main body 31, so that current can be collected directly from the outer peripheral side of the electrode body 15 having a large electrode area. Therefore, the current collection efficiency of the cylindrical battery 10 can be increased.
[0028]
After the negative electrode current collector 30 and the case 11 are connected, as shown in FIG. 1, an annular protrusion 14 is formed, and the electrode body 15 is fixed. Then, at this stage, the electrolytic solution is injected, and subsequently, the connection projection piece 26 of the connection body 25 provided on the back surface of the sealing plate 23 and the connection piece 22 of the positive electrode current collector 20 are welded. While being pressed downward, the upper end portion of the case 11 is crimped to the insulating packing 24 of the sealing plate 23 to complete the assembly of the cylindrical battery 10.
[0029]
As described above, according to the present embodiment, the lead piece 34 of the negative electrode current collector 30 is provided so as to extend from the outer peripheral edge of the current collector body 31 and can collect current directly from the outer peripheral side of the electrode body 15. Thus, the current collection efficiency of the cylindrical battery 10 can be improved.
[0030]
Further, by providing the welded portion 42 at a position eccentric from the axis of the electrode main body 41 of the spot welding electrode 40, the contact position of the welded portion 42 with respect to the contact portion 36 of the lead piece 34 can be changed by rotating the spot welding electrode 40. This allows spot welding to be performed at two locations. Since welding can be performed at two locations, the contact reliability between the negative electrode current collector 30 and the case 11 can be improved, and further, current concentration at the welding location can be prevented and resistance loss can be prevented as much as possible. Can do. Moreover, secondary welding can be performed as well as possible by setting the welding power at the time of secondary welding to a larger value than that of primary welding.
[0031]
<Second Embodiment>
Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the lead pieces 34 of the negative electrode current collector 30 are provided at two locations.
That is, as shown in FIG. 7, the other lead piece 34B is provided at a position 180 degrees from the one lead piece 34B on the outer peripheral edge of the current collector main body 31, and the lengths of these lead pieces 34B are provided. Is a length that covers the center hole 32 in the folded state. Other structures, operations, and effects are the same as those in the first embodiment described above, and will be omitted.
[0032]
Since the lead piece 34B is provided at two positions on the outer peripheral edge of the current collector main body 31, the current can be collected more uniformly from the outer peripheral side of the electrode body, and the current collection efficiency is further improved. Can be made.
[0033]
<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
(1) In the above-described embodiment, the case where the present invention is applied to a cylindrical nickel-hydrogen secondary battery has been shown. However, the main point is that the battery has a cylindrical shape and the electrode area of the electrode body is large on the outside. For example, it can be applied regardless of the type of battery, such as an alkaline battery or a lithium ion battery.
(2) In the above-described embodiment, the case where the present invention is applied to the negative electrode current collector has been described. However, the present invention may be applied to the positive electrode current collector as long as it is connected to the bottom of the case.
(3) In the above-described embodiment, the number of lead pieces is one and two. However, three or four lead pieces may be used, and when a plurality of lead pieces are provided, they are equiangularly spaced. It does not have to be arranged.
(4) In the above-described embodiment, the case where the welding is performed at two places is shown, but the case where the welding is performed at three places or more is also included in the present invention.
(5) Furthermore, when welding is performed at three or more locations, the present invention includes a case where the welding power is increased as the number of weldings increases.
(6) In the above-described embodiment, the shape of the spot welding electrode is a round bar, but it is only necessary that the spot welding electrode has a shaft shape. For example, an electrode body having a square bar shape is also included in the present invention. It is.
(7) The present invention is applicable to a case where a spot welding is performed only once as long as the battery uses a lead piece extending from the outer peripheral edge of the current collecting main body, and a connection method other than spot welding. It can also be applied when using.
(8) The present invention can be applied regardless of the shape of the current collector as long as spot welding is performed twice or more.
[Brief description of the drawings]
1 is a cross-sectional view of a cylindrical battery according to a first embodiment of the present invention. FIG. 2 is a plan view of a negative electrode current collector. FIG. 3 is a cross-sectional view illustrating an operation of inserting an electrode body into a case. ] Cross-sectional view showing the operation of inserting the spot welding electrode into the air core [FIG. 5] Enlarged cross-sectional view showing the state after the primary welding [FIG. 6] Enlarged cross-sectional view showing the state after the secondary welding [FIG. 7] Plan view of a negative electrode current collector according to the second embodiment of the present invention. [FIG. 8] A cross-sectional view showing a conventional cylindrical battery. [FIG. 9] An enlarged cross-sectional view showing a welding operation.
10 ... Cylindrical battery (cylindrical battery)
DESCRIPTION OF SYMBOLS 11 ... Case 13 ... Bottom part 15 ... Electrode body 16 ... Positive electrode plate 17 ... Negative electrode plate 18 ... Separator 19 ... Air core part 30 ... Negative electrode collector (current collector)
31 ... Current collector body 32 ... Center hole 34 ... Lead piece 36 ... Contact 40 ... Spot welding electrode 41 ... Electrode body 42 ... Weld 50 ... Primary welding location 51 ... Secondary welding location

Claims (5)

An electrode body in which a positive electrode plate and a negative electrode plate are wound with a separator sandwiched between both electrode plates, a bottomed cylindrical case capable of accommodating the electrode body, and one of the electrode bodies connected to the electrode body In a cylindrical battery comprising a current collector for connecting the electrode plate and the case,
The current collector includes a current collector body portion addressed over substantially the entire end face of the electrode body, and a lead piece extending from an outer peripheral edge thereof and connected to a bottom portion of the case, and the current collector body The cylindrical battery is characterized in that a slit extending in the radial direction is provided in the portion, and a side along the radial direction of the slit is a bent portion that is bent toward the electrode body side and connected to the electrode body. .   The cylindrical battery according to claim 1, wherein the current collector includes a plurality of the lead pieces. An electrode body in which a positive electrode plate and a negative electrode plate are wound in an air-core shape with a separator sandwiched between both electrode plates, a bottomed cylindrical case that can accommodate the electrode body, and an end face of the electrode body A method of manufacturing a cylindrical battery having a current collector that is addressed and connected to one of the electrode plates and welded to the bottom of the case,
A spot welding electrode for welding the current collector and the case can be inserted into the air core portion formed in the electrode body, and at the tip of the spot welding electrode, the electrode body A weld is formed at a position eccentric from the axis, and after performing the primary welding with the current collector sandwiched between the weld and the bottom of the case, the spot welding electrode is rotated, A method for manufacturing a cylindrical battery, comprising performing secondary welding with the current collector sandwiched between the welded portion and the case.   4. The method for manufacturing a cylindrical battery according to claim 3, wherein welding power in the secondary welding is made higher than that in the primary welding. An electrode body in which a positive electrode plate and a negative electrode plate are wound in an air-core shape with a separator sandwiched between both electrode plates, a bottomed cylindrical case that can accommodate the electrode body, and an end face of the electrode body In a cylindrical battery that is addressed and connected to one electrode plate and is welded to the bottom of the case, the spot welding electrode is used for spot welding the current collector to the bottom of the case. ,
It consists of a shaft-type electrode body inserted into the air core portion of the electrode body and a welded portion formed at the tip thereof, and this welded portion is provided at a position eccentric from the axis of the electrode body. A spot welding electrode for a current collector for a battery.

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