JPH1167187A - Battery and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To take out a large current while avoiding lowering of welding quality between an electrode plate and a collector plate, lowering battery resistance and unevenness in electric potential of each electrode plate, so as to avoid the loss by previously bonding plural collector prates to an electrode plate through resistance welding or the like, and bonding each collector plate to a current-collecting secondary electrode plate so as to connect each collector plate to an external extraction terminal. SOLUTION: A positive terminal 7 consists of a disc-like secondary collector part (current-collecting secondary collector plate) 71 and a positive electrode terminal part (external extraction terminal) 72. Lower end surfaces of six collector plates 8, arranged radially around a core are welded to an edge part 61 of a positive electrode plate 6 by resistance welding, and an upper end surfaces thereof are welded to a lower end surface of a secondary collector part 71 of the positive terminal 7. A negative electrode plate side is provided with identical in shape to the collector plates and identical attitude with the positive electrode side, the and the similar connection is made. With this structure, positive electrode plates 6 and the collector plates 8 can be bonded securely to each other over a wide range by resistance welding, and electrical resistance between the positive electrode plates 6 and the positive electrode terminal part 72 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a battery and a method for manufacturing the battery.

[0002]

2. Description of the Related Art In a conventional cylindrical sealed battery, an electrode assembly formed by spirally winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween is sealed together with an electrolyte in a cylindrical can-shaped case. To improve the battery performance by suppressing the potential variation of each part of the positive plate by resistance welding the lower surface of the current collector plate with terminals (also called external lead terminals or terminals) to each part of the upper edge of the positive plate. Has been proposed. In addition, reduction of the potential variation of each part of the positive electrode plate is particularly important in terms of suppressing a reduction in high rate discharge capacity or output and cycle life due to local overcharge and overdischarge.

In order to resistance-weld the lower surface of the current collector plate to the metal band joined to the upper edge of the positive electrode plate, a pair of welding electrode tips pressed against the upper surface of the current collector plate at a predetermined distance from each other are required. The welding current is caused to flow between the current collector plate and the metal band at the upper edge of the positive electrode plate, thereby generating heat at the contact portion between the current collector plate and the positive electrode plate. In a sealed cylindrical battery, a current collector is resistance-welded to a metal band joined to a lower edge of a negative electrode plate, and then a welding electrode tip is inserted into an air-core portion of the electrode assembly, and the end of the current collector is attached to the current collector. It is also proposed that the current collector plate be welded to the bottom of the case by applying a current between the welding electrode tip and the bottom of the case.

[0004]

However, the above-described conventional current collector plate resistance welding method has the following problems. First, in order to suppress the increase in the battery resistance and the variation in the potential of each part of the positive electrode plate and increase the diameter and the capacity of the battery, the thickness of the current collector plate must be increased to increase the resistance loss due to the increase in current. Deterrence is essential. However, when the current collector plate is thickened, a bypass current flowing directly between the two welding electrode tips through the current collector plate increases, and as a result, one of the welding electrode tips, the current collector, the positive electrode plate, the current collector, and the other. The current for generating heat at the welding point flowing in the path of the welding electrode tip was decreased, and the possibility that the welding between the current collector plate and the positive electrode plate became defective was increased.

[0005] Therefore, a pair of current collector plates are separated from each other and brought into contact with the side edge (upper edge) of the positive electrode plate. It is considered that the current is set to 0. However, in this case, a positive electrode terminal, that is, an external lead-out terminal is provided on one of the current collectors. However, since the current collected on the other current collector cannot be concentrated on the positive electrode terminal, the electric resistance of the positive electrode is effectively reduced. The problem arises that it is not possible to achieve this.

In the above resistance welding, current mainly flows from the current collector plate to the positive electrode plate immediately below the electrode terminal for welding, so that welding is mainly performed immediately below the push contact of the electrode tip for welding. It occurs near. Therefore, it is preferable to increase the number of welding locations by performing resistance welding a plurality of times while changing the position of the welding electrode tip. However, in the resistance welding after the first resistance welding is performed, there is also a problem that good resistance welding is difficult because most of the current flows around a low resistance path generated by the first welding.

Further, when the current collector plate is made thicker, its rigidity increases. However, when resistance welding is performed a plurality of times, irregularities due to welding marks are formed on the current collector plate, and the pressing of the welding electrode tip during the next resistance welding is performed. As a result, there was a possibility that the previous welded part was peeled off. The above-described problems also occur when the current collector plate is resistance-welded to the negative electrode plate. In this case, a pair of current collector plates are separated from each other and brought into contact with a side edge (lower edge portion) of the negative electrode plate of the cylindrical sealed battery, and a welding electrode tip is pressed against each of the current collector plates to conduct electricity. It is also conceivable to set the above-mentioned bypass current to zero.

More specifically, a welding electrode tip is inserted into a hollow portion of a cylindrical electrode assembly, and the electrode tip for welding is brought into contact with the welding electrode tip in contact with the outer surface of the case bottom of the case. By energizing, the current collector plate is resistance-welded to the inner surface of the bottom of the can. However, in this case, since a plurality of current collectors are energized only at the contact surface with the welding electrode tip through the air core portion, the welding current is limited to a part of the current collectors due to a variation in the joining position of the current collectors. And it is not easy to reliably weld each current collector plate to the bottom of the can.

The present invention has been made in view of the above problems, and realizes a reduction in battery resistance and a reduction in potential variation in each part of an electrode plate while avoiding a decrease in welding quality between the electrode plate and the current collector. It is an object of the present invention to provide a battery capable of extracting a large current with low loss and a method of manufacturing the same.

[0010]

According to the first aspect of the present invention, the current collecting member includes an external lead-out terminal serving as a terminal (terminal) for transmitting and receiving an electric current to / from the outside, and a pole separated from each other. At least one pair of current collectors joined to the side edges of the plate, and a current collector secondary current collector joined to both current collectors to concentrate currents of both current collectors to external lead terminals . With this configuration, the following operation and effect can be obtained.

First, since the side edge of the electrode plate has a variation in size and shape (for example, unevenness or bend) due to the influence of the manufacturing process or the like, a single current collector is connected to the side edge of the electrode plate. It is not easy to join by resistance welding or the like over almost the entire surface or a wide range thereof. Therefore, according to this configuration, a plurality of current collector plates are provided, and the current collector plates are joined to the side edges of the electrode plates while being separated from each other. In this way, the influence of the unevenness of each part of the side edge of the electrode plate is reduced, so that even if the current collector plate is a thick plate, it is satisfactorily joined to the side edge of the electrode plate by resistance welding or the like. .

More specifically, in the case where a single current collector having a large area is pressed against the side edge of the electrode plate and joined by resistance welding or the like, it is difficult for current to flow in the concave portion of the side edge of the electrode plate. This makes resistance welding difficult, resulting in an increase in electrode resistance and heat generation. In contrast, in this configuration, a plurality of current collectors with a relatively small area are joined to the electrode plates in advance by resistance welding or the like, and then each current collector is joined to a secondary current collector for current collection. By doing so, each current collector plate is connected to an external lead-out terminal. In this way, the electrode plate and the current collector can be securely joined to each other over a wide area by welding or the like, and each current collector and the current collector secondary current collector are pressed against each other. Therefore, it can be relatively easily joined by laser welding, resistance welding, etc., and eventually, even in a large and large capacity battery, the electric resistance between the electrode plate and the external lead-out terminal is reduced. be able to. The external lead-out terminal can be formed integrally with the current collecting secondary current collector or joined to the current collecting secondary current collector.

Further, according to the present invention, a second aspect described below is provided.
Since the described method can be adopted, a current collector joining structure excellent in joining properties can be realized with a simple process even with a large current collector plate. According to the configuration of claim 2, first, at least a pair of current collectors are brought into contact with the side edge of the electrode plate in a state of being separated from each other, and then a welding current is applied between the two current collectors to perform resistance welding. After that, a secondary current collector for current collection is welded to each current collector, so that the battery quality is reduced and the potential of each part of the electrode is reduced while avoiding deterioration of welding quality between the electrode and the current collector. Variation can be reduced, and a method for manufacturing a battery that can extract a large current with low loss can be realized. More specifically, since the above-described bypass current does not occur when a thick current collector plate having a low resistance value is resistance-welded to an electrode plate, even if the current collector plate becomes large, the welding current is increased due to an increase in the bypass current. The decline can be eradicated.

As will be described in detail later in the embodiments, in the above-described resistance welding, the selection of the current collector plate can be changed in various ways. Therefore, even in the next resistance welding after the first resistance welding is performed, most of the current is supplied to the first welding. Therefore, it is possible to suppress the problem of flowing around the low-resistance path caused by the above, and it is possible to suppress a decrease in welding quality. Further, claim 1
As described above, excellent resistance welding of the current collector plate to each side edge of the electrode plate can be performed despite the unevenness of each side edge portion of the electrode plate.

According to the third aspect of the present invention, in the battery manufacturing method of the second aspect, the secondary current collecting plate for current collection also serves as an external lead-out terminal. In addition to the above, the effect of reducing the number of parts and simplifying the configuration can be obtained. According to a fourth aspect of the present invention, in the method for manufacturing a battery according to the second or third aspect, the current collector plate further crosses a side edge of each of the winding pieces of the cylindrically wound electrode plate. It is arranged in a posture, preferably in a substantially radial direction. According to this configuration, in addition to the effect of the configuration of the second aspect, it is possible to realize an effect of effectively collecting the current of the winding piece on the outer peripheral portion of the electrode plate of the cylindrical battery to the external extraction terminal.

According to a fifth aspect of the present invention, there is provided the battery manufacturing method according to any one of the second to fourth aspects, further comprising a welding part inserted into the hollow core of the cylindrically wound electrode assembly. By applying electricity between the electrode tip and the bottom of the can,
Since the secondary current collector for current collection is welded to the bottom of the can of the cylindrical battery, the welding can be performed reliably and firmly. More specifically, when the current collector plate welded to the side edge (lower edge portion) of the electrode plate (negative electrode plate) is directly welded to the bottom of the case, the current flows between the current collector plate and the bottom of the can. Was distributed over the entire contact surface having a wide area, and welding was not easy. It is possible to concentrate the welding current by providing irregularities on the joint surface between the two, but an extra shaping process is required.

According to this configuration, since the secondary current collector for current collection does not directly contact the electrode plate, it is not necessary to form the secondary current collector as widely as the current collector. The welding current flowing through the secondary current collector for current collection by the current flowing between the inserted welding electrode tip and the bottom of the can concentrates on the contact surface between the secondary current collector for current collection and the bottom of the can. Therefore, welding can be performed well.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a battery, a stacked battery can be used in addition to a cylindrical sealed battery, and for example, a nickel hydrogen battery can be used as a battery type. As the positive electrode plate (positive electrode plate) of the nickel-metal hydride battery, a material obtained by filling a paste containing nickel hydroxide powder in foamed nickel, nickel felt, nickel matte, or the like can be used.

As the negative electrode plate (negative electrode plate) of the nickel-metal hydride battery, a foamed nickel, punched metal, expanded metal, nickel matte or the like filled with a paste containing a hydrogen storage alloy powder can be used. As the hydrogen storage alloy powder, a misch metal material is preferable.
Other materials such as zirconium-based and titanium-based materials can be used.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A sealed cylindrical nickel hydride battery to which the present invention is applied will be described below. (Embodiment 1) FIG. 1 is an axial partial cross-sectional view of a positive electrode side half of a cylindrical sealed nickel hydride battery of this embodiment.

Reference numeral 1 denotes a cylindrical case whose one end opening is closed by a disk-shaped cover plate 3 via a resin ring 2 for electrical insulation. 4 is a safety valve. Reference numeral 5 denotes an electrode assembly, which is formed in a cylindrical shape by stacking a positive electrode plate 6 and a negative electrode plate via a separator (not shown) and spirally winding them. However, in FIG. 1, the electrode assembly 5 is schematically illustrated, and the separator and the negative electrode plate are not illustrated. Reference numeral 61 denotes an upper edge (side edge) of the positive electrode plate 6, and a nickel strip is welded to this edge. The broken line b indicates the position of the upper edge of the negative electrode plate (not shown). The upper edge of the separator is provided to a position near the edge 61 of the positive electrode plate 6 for electrical insulation between the two electrodes.

Reference numeral 7 denotes a + terminal, which is made of a nickel plate or a nickel-plated conductor plate. + Terminal 7
Is a disk-shaped secondary current collector (secondary current collector in the present invention)
71 and the cover plate 3 from the radial center position of the secondary current collector 71.
And a positive electrode terminal portion (external extraction terminal in the present invention) 72 protruding outward in the axial direction. Numeral 8 denotes six current collector plates radially arranged around the axis as shown in FIG. 2, and the lower end surface thereof has an upper edge of the positive electrode plate 6, as will be described later in detail. The upper end surface of the secondary current collector portion 71 of the + terminal 7 is resistance-welded to the Ni lead of the portion 61.
Is welded to the lower end face. Each current collector 8 has an angle of about 30
It is made of a nickel plate or a nickel-plated conductor plate having a circular shape. A point W indicates a portion to which the welding electrode tip is pressed during resistance welding. A ridge 8a is formed in the radial direction on the end face of the current collector plate 8 on the side of the electrode plate, that is, on the lower end face in this case for current concentration.

FIG. 3 shows a state in which the negative electrode plate 9 and the bottom 1a of the cylindrical case 1 are joined. In FIG. 3, the electrode assembly 5 is schematically illustrated, and the separator and the positive electrode plate 6 are not illustrated. Reference numeral 91 denotes a lower edge (side edge) of the negative electrode plate 9, and a nickel strip is welded to this edge. The solid line c indicates the position of the lower edge of the positive electrode plate (not shown). The lower edge of the separator is provided up to a position near the edge 91 of the negative electrode plate 9 for electrical insulation between the two electrodes.

Numeral 10 denotes six current collectors arranged radially about the axis as shown in FIG. 4, which are arranged in the same shape and the same posture as the current collector 8 described above. As will be described in detail later, the upper end face is resistance-welded to the lower edge 91 of the negative electrode plate 9, and the lower end face is resistance-welded to the secondary current collector plate 11 for current collection. Each current collector 10
Consists of a nickel plate or a nickel-plated conductor plate having a circular shape with an angle of about 30 degrees. A point W indicates a portion to which the welding electrode tip is pressed during resistance welding. A ridge 10a is formed in the radial direction on the end face of the current collector plate 10 on the electrode plate side, that is, on the upper end face in this case for current concentration.

The secondary current collector 11 for current collection has the same disk shape as the secondary current collector 71 and is made of a nickel plate or a nickel-plated conductor plate. The upper end surface of the secondary current collector plate 11 is resistance-welded to the current collector plate 10, and the lower end surface thereof is a can bottom 1a.
Resistance welding. The method for assembling this battery will be described below. First, six current collectors 8 are arranged on the edge portion 61 of the positive electrode plate 6, and the positive-side welding electrode tips are pressed against the points W of the three current collectors 8 separated by about 120 degrees from each other. About 1
The negative electrode tip for welding is pressed against the point W of the remaining three current collecting plates 8 separated by 20 degrees, and a welding current is supplied. The point W is preferably on the ridge 8a described above. As a result, a welding current flows through the positive-side current collector 8, the positive electrode 6, and the negative-side current collector 8, and resistance welding is performed.

Next, the current collector plate 10 is resistance-welded to the lower end edge of the negative electrode plate 9 in exactly the same manner as the resistance welding of the current collector plate 8, and the same method as the resistance welding of the + terminal 7, which will be described later. Then, the secondary current collector 11 is resistance-welded to the current collector 10. Next, the electrode assembly 5 having been subjected to the above-described resistance welding is accommodated in the case 1, the welding electrode tip 14 is inserted into the hollow core portion 13, and its tip is placed on the upper surface of the secondary current collector plate 11. (See FIG. 3). On the other hand, when a welding plate 15 is pressed against the outer surface of the can bottom 1a of the case 1 and a welding current is applied between the welding electrode tip 14 and the welding electrode plate 15, the secondary current collector 11 Resistance welding is performed on the bottom 1a.

Next, the secondary current collector 71 of the + terminal 7
Is pressed onto the current collecting plate 8, the negative welding electrode tip is pressed against each current collecting plate 8, the + terminal 7 is connected to the positive side of the welding power source, and electricity is supplied, and they are resistance-welded. Next, the cover plate 3 on the positive electrode side is attached to the case 1, and the positive electrode terminal portion 72 of the + terminal 7 and the cover plate 3 are welded. (Modification 1) In the above-described embodiment, each current collector plate 8, 10
Although resistance welding has been described at a glance, it is naturally possible to perform welding one by one. In this case, the first current collector and the second current collector are welded, then the second current collector and the third current collector are welded, and thereafter, welding is performed in this order. If repeated, welding can be performed twice without detour current per collector plate. (Modification 2) Another modification will be described with reference to FIG.

In this embodiment, the current collector is a rectangular plate,
Four pieces are arranged in a cross. It is clear that the same effect as in the first embodiment can be obtained even in this case.

[Brief description of the drawings]

FIG. 1 is an axial partial cross-sectional view of a half part on the positive electrode side in a battery of Example 1.

FIG. 2 is a plan view showing an arrangement of a current collector 8 and a + terminal 7 in FIG.

FIG. 3 is a partial cross-sectional view showing a current collecting structure on a negative electrode side in the battery of FIG.

FIG. 4 is a plan view showing an arrangement of a current collector plate 10 and a secondary current collector plate 11 of FIG.

FIG. 5 is a plan view showing a modification of the current collector 8;

[Explanation of symbols]

1 is a case, 5 is an electrode assembly, 6 is a positive electrode plate, 7 is a + terminal, 8 is a current collector plate, 9 is a negative electrode plate, 10 is a current collector plate, 11 is a secondary current collector plate (current Reference numeral 61 denotes an edge portion (side edge) of the positive electrode plate 6, reference numeral 71 denotes a secondary current collector portion (current collection secondary current plate), reference numeral 72 denotes a positive terminal. The positive terminal portion (external lead terminal) of the terminal 7, 91 is an edge portion (side edge) of the negative electrode plate 9.

Claims (5)

[Claims] An electrode assembly formed by laminating or winding a pair of positive and negative electrode plates with a separator interposed therebetween; a case having an external lead-out terminal for accommodating the electrode assembly; and the electrode plate. A current collector that is welded to a side edge of the electrode plate and that collects current with the electrode plate, wherein the current collector member is separated from an external lead-out terminal for external connection and a side edge of the electrode plate. A plurality of current collector plates formed of thick plates joined together, and a secondary current collector plate for current gathering which is joined to each of the current collector plates and concentrates the currents of the two current collector plates to the external lead-out terminals A battery comprising: 2. An electrode assembly is formed by laminating or winding a pair of positive and negative electrode plates with a separator interposed therebetween, and at least a pair of current collector plates are brought into contact with side edges of the electrode plates while being separated from each other. Thereafter, a welding current is applied between the two current collector plates, and the two current collector plates are resistance-welded to the electrode plates. Thereafter, a secondary current collector plate for current collection is welded to each of the current collector plates. A method for producing a battery, comprising: 3. The method for manufacturing a battery according to claim 2, wherein the secondary current collecting plate for current collection also serves as an external lead-out terminal. 4. The method for manufacturing a battery according to claim 2, wherein the current collecting plate is disposed in a posture crossing a side edge of each winding piece of the electrode plate wound in a cylindrical shape. A method for producing a battery, comprising: 5. The method for manufacturing a battery according to claim 2, wherein the secondary current collector for current collection is inserted into an air core of the electrode assembly wound in a cylindrical shape. A method for producing a battery, characterized in that the battery is welded to the bottom of the cylindrical battery by energization between the welded electrode tip and the bottom of the case.