JP2001338632A - Battery and manufacturing method of battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery that enables to connect and fix steadily the current collector with connecting members such as a terminal connecting member 6 or a positive electrode 1a and the manufacturing method of the battery. SOLUTION: The convex joining portions 4b, 6b having a widening top end are formed by pressing process by laying the connecting portion 6a of a terminal connecting member 6 that is connected and fixed with a terminal 3 on the connecting portion 4a of a current collector 4 and then connected and fixed. And a convex is formed on another metal plate which is disposed opposed to the U shape portion of the corrugated iron sheet 4e provided in the current collector 4, and is connected and fixed by supersonic welding from the direction of the metal plate by interposing the plural sheets of positive electrodes 1a of the battery element 1 in this U shape portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery for connecting an electrode of a battery element to a terminal via a current collector, and a method for manufacturing the battery.

[0002]

2. Description of the Related Art FIG. 16 shows an example of a structure of a lithium ion secondary battery using a current collector. In this lithium ion secondary battery, a long cylindrical battery element 1 is housed in a battery case of a long cylindrical container shape (not shown), and a positive electrode attached to a lid plate 2 closing an upper end opening of the battery case. Current collectors 4, 4 are used to connect the negative terminals 3, 3 to the positive and negative electrodes of the battery element 1 inside the battery case. As shown in FIG. 17, the battery element 1 is formed by winding a strip-shaped positive electrode 1a and a negative electrode 1b up and down via a separator 1c and winding them into a long cylindrical shape. The aluminum foil which is the active material uncoated portion of the positive electrode 1a protrudes, and the copper foil which is the active material uncoated portion of the negative electrode 1b protrudes from the lower end side. In the drawings, the number of windings of the positive and negative electrodes 1a and 1b is shown to be small for easy understanding, but in actuality, many windings are performed very densely.

The cover plate 2 is an elliptical plate made of the same aluminum plate or stainless steel plate as the battery case. The cover plate 2 is fitted into the upper end opening of the battery case having a long cylindrical shape and welded around. Seal the inside of the battery case. As shown in FIG. 18, the cover plate 2 has through holes formed at both ends and a safety valve 2a formed at the center. In addition, packings 5,
5 are arranged, and terminal connection pieces 6 and 6 are arranged at both lower ends of the packing 5 on the lower surface side. Packing 5,5
Is an oblong plate-like molded product made of insulating PPS (polyphenylene sulfide), PP (polypropylene), fluororesin, etc., and has through holes formed at both ends,
In the packing 5 on the upper surface, the lower edge of the through hole is fitted into the through hole of the cover plate 2. In addition, the terminal connection pieces 6 and 6 have through holes formed therein, and are arranged at positions where the through holes overlap the through holes of the cover plate 2 and the packings 5 and 5. The positive and negative terminals 3 and 3 are components having a male screw portion projecting upward from the flat upper surface of the connecting portion and a cylindrical caulking portion projecting downward from the lower surface of the connecting portion. Yes, it is used to connect a lithium ion secondary battery to an external circuit. Then, the swaged portions of the positive and negative terminals 3 and 3 are connected to the packings 5 and 5 and the terminal connecting pieces 6 and
6, the terminals 3, 3 and the terminal connection pieces 6, 6 are respectively connected and fixed by pushing the caulked portion from below into the through hole of the cover plate 2 and expanding the caulked portion. The space between the cover and the cover plate 2 is insulated and sealed. The positive electrode terminal 3 is made of an aluminum material, and the negative electrode terminal 3 is made of a copper material. The terminal connection piece 6 connected and fixed to the positive terminal 3 is made of an aluminum plate, and the terminal connection piece 6 connected and fixed to the negative terminal 3 is made of a copper plate.

A positive electrode current collector 4 shown on the front side of FIG.
A corrugated plate portion 4e made of an aluminum plate, the lower portion of which is formed by bending the aluminum plate into a corrugated plate to form a plurality of U-shaped portions.
As shown in FIG.
7 is connected to the aluminum foil of the positive electrode 1a, and the upper connecting portion 4a is connected to the positive electrode terminal 3 under the cover plate 2.
Is connected to the connection portion 6a of the terminal connection piece 6 which is crimped. The negative electrode current collector 4 shown in the back side of FIG. 16 is made of a copper plate, and the copper plate is bent into a corrugated shape to form a plurality of U-shaped portions. The lower end surface of the long cylindrical shape is connected to the copper foil of the negative electrode 1b shown in FIG. 17, and the upper end connecting portion 4a pulled out through the side surface of the battery element 1 is connected to the negative terminal 3 Is connected to the connection portion 6a of the terminal connection piece 6 which is crimped. Thereby, the positive electrode 1a of the battery element 1 is connected to the positive terminal 3 via the current collector 4 on the positive electrode side and the terminal connecting piece 6, and the negative electrode 1b of the battery element 1 is connected to the negative electrode collector. It is connected to the negative terminal 3 via the electric body 4 and the terminal connecting piece 6.

[0005] When the lithium ion secondary battery is small, the connection between the current collector 4 and the terminal connection piece 6 is generally performed by needle caulking. That is, the connecting portion 4a of the current collector 4 and the connecting portion 6a of the terminal connecting piece 6 are overlapped, and a needle-like jig is pressed against these connecting portions 4a, 6a to pierce the metal plate and make holes. The metal plates of the current collector 4 and the terminal connection pieces 6 are connected and fixed by the return of the holes.
The connection between the current collector 4 and the electrode of the battery element 1 is as follows.
A plurality of metal foils for the electrodes are sandwiched between the U-shaped portions of the corrugated plate portion 4e formed on the current collector 4 and ultrasonically welded from both sides of each U-shaped portion of the corrugated plate portion 4e. The connection was fixed.

[0006]

However, since the above-mentioned needle caulking only reliably comes into contact with only the return portion of the hole,
The contact resistance between the current collector 4 and the terminal connection piece 6 increases. However, when the lithium-ion secondary battery becomes large, it is necessary to perform high-rate charging and discharging, so when a large current of high-rate discharging flows in such a needle caulking portion, for example,
There is a problem that the voltage drop increases and the battery output decreases.

In the case of a small lithium ion secondary battery, the thickness of the current collector 4 and the terminal connection piece 6 is about 0.1 mm, but a large lithium ion secondary battery can charge and discharge at a high rate. To perform this, the plate thickness of the current collector 4 and the terminal connection piece 6 is set to 2.0.
It is necessary to stack a plurality of thin metal plates so as to increase the thickness to about mm or to obtain an equivalent current capacity. However, when the thickness of the current collector 4 or the terminal connection piece 6 is increased or the number of the current collector 4 or the number of the terminal connection pieces 6 is increased, the needle-shaped jig does not stick easily, and there is a problem that it is difficult to perform connection processing by needle swaging. .

Further, in connection between the corrugated plate portion 4e of the current collector 4 and the electrode of the battery element 1, a large number of metal foils are interposed between the U-shaped portions of the corrugated plate portion 4e via a metal plate. Since ultrasonic welding is performed, there has been a problem that it is not easy to perform stable welding.

The present invention has been made in order to cope with such a situation, and an object of the present invention is to provide a battery and a method for manufacturing the battery, which can securely fix the current collector to the connection piece. I have.

[0010]

According to a first aspect of the present invention, there is provided a battery, wherein at least one metal plate of a current collector connected to an electrode of a battery element and one of connecting pieces connected to the current collector are provided. The fastening portions formed on at least one metal plate and having a concave front surface side and a convex rear surface side were connected and fixed by fitting a convex shape having a distal end portion extending in a peripheral shape into a concave shape with a widened depth. It is characterized by the following.

According to the first aspect of the present invention, the convex shape in which the distal end portion of the fastening portion of the other metal plate expands fits into the concave shape in which the depth of the fastening portion of the adjacent one metal plate is widened. The current collector made of these metal plates and the connection piece are securely and securely connected and fixed without falling off, and the contact resistance between them is also reduced. Therefore, even if the battery is charged and discharged at a high rate, the voltage drop at the connection portion does not increase. In addition, the concave shape of the fastening portion where the convex shape does not fit does not necessarily have to be deeper, and the convex shape of the fastening portion which is not fitted in the concave shape does not necessarily need to have the leading end portion spread around.

According to a second aspect of the invention, there is provided a method of manufacturing a battery, wherein one or more metal plates of a current collector connected to the electrodes of the battery element and one or more connection pieces connected to the current collector are provided. A metal-plate is superposed, and a concave die whose inner peripheral surface can move around against the inward biasing force is arranged on the back side of these superposed metal plates, and the front side is a convex punch. By pressing the metal plates, a fastening portion is formed which protrudes to the rear surface side and has a front end portion which is widened around, and these metal plates are caulked and fixed.

According to the second aspect of the present invention, when the stacked metal plates are pressed by the convex punch, the inner peripheral surface of the concave die escapes to the periphery, so that the metal die is formed by being pressed by the punch. The distal end portion of the convex fastening portion swells, and the metal plates can be securely and firmly connected and fixed. Therefore, the contact resistance between these metal plates is reduced, and even if the battery is charged and discharged at a high rate, the voltage drop at the connection portion does not increase. Further, since the current collector and the metal plate of the connection piece are connected and fixed by pressing, the processing becomes easy even if the thickness of these metal plates is increased to some extent or the number is increased.

According to a third aspect of the invention, there is provided a method for manufacturing a battery, wherein at least one metal plate of a current collector connected to the electrode of the battery element and at least one piece of a connection piece connected to the current collector are provided. First, press the front side of these stacked metal plates with a convex punch to form a fastening part that projects to the back side, and then press the tip of this fastening part from the back side. Then, these metal plates are caulked and connected and fixed by pushing the front end portion around.

According to the third aspect of the present invention, a convex fastening portion is first formed by pressing the superposed metal plates with a convex punch, and then the fastening portion is pressed from the opposite direction. The metal plates can be securely and firmly connected and fixed by inflating the distal end portion. Therefore, the contact resistance between these metal plates is reduced, and even if the battery is charged and discharged at a high rate, the voltage drop at the connection portion does not increase. Further, since the current collector and the metal plate of the connection piece are connected and fixed by pressing, the processing becomes easy even if the thickness of these metal plates is increased to some extent or the number is increased.

According to a fourth aspect of the present invention, the metal plate of the current collector connected to the electrode of the battery element overlaps with the metal plate of the connecting piece connected to the current collector, and either one of the metal plates overlaps with the other. A protrusion formed on the other metal plate is fitted into a through hole formed on the metal plate, and the tip of the protrusion is spread around and fixed by caulking.

According to the fourth aspect of the present invention, the tip of the convex portion of the other metal plate fitted into the through hole of one metal plate is swollen and swaged, so that the current collector and the connection piece are firmly and firmly connected. And the contact resistance between them is also reduced. Therefore, even if the battery is charged and discharged at a high rate, the voltage drop at the connection portion does not increase.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a battery, comprising the steps of: providing one of a metal plate of a current collector connected to an electrode of a battery element and a metal plate of a connecting piece connected to the current collector; Along with forming a through hole, a convex portion is formed on the other metal plate, these metal plates are overlapped, and a convex portion of the other metal plate is fitted into the through hole of one metal plate, and the other metal plate has a convex portion. It is characterized in that these metal plates are caulked and connected and fixed by pressing the front end of the convex portion of the other metal plate fitted into the through hole and expanding it around.

According to the fifth aspect of the present invention, the protrusions of the other metal plate are fitted into the through-holes of the one metal plate, and the tips of the protrusions are swaged to expand the metal plates. Can be connected and fixed. Therefore, the contact resistance between these metal plates is reduced, and even if the battery is charged and discharged at a high rate, the voltage drop at the connection portion does not increase. Further, since the current collector and the connection piece having the through holes and the projections formed in advance can be connected and fixed only by caulking, even if the thickness of these metal plates becomes large, the processing becomes easy.

According to a sixth aspect of the invention, there is provided a battery and a method for manufacturing a battery, wherein the through-hole is a round hole, and the inner diameter of the through-hole is smaller at the end opposite to the side where the projection is fitted. It is characterized in that an increasing taper is formed.

According to the sixth aspect of the present invention, the taper is formed in the through-hole, so that the bulge at the tip of the projection fitted into this through-hole prevents the metal plate from coming into contact with each other and makes the metal plates more closely contact each other. Thus, the connection and fixing of these metal plates can be made even more reliably.

According to a seventh aspect of the present invention, there is provided a battery according to the present invention, wherein at least one metal plate of a current collector connected to the electrode of the battery element and at least one metal plate of a connecting piece connected to the current collector are provided. The metal foil overlaps on at least one convex portion formed on the metal plate of the current collector, and these metal plates and the metal plate or the metal foil are welded and fixed by ultrasonic welding. It is characterized by.

According to the seventh aspect of the present invention, since the metal plate or the metal foil of the connection piece is welded on the convex portion formed on the metal plate of the current collector by ultrasonic welding, the welding energy is reduced. Welding can be reliably performed even when there are many metal plates and metal foils.

According to an eighth aspect of the invention, there is provided a method for manufacturing a battery, wherein a convex portion is formed on a metal plate of a current collector connected to an electrode of a battery element, and the current collector is formed on the convex portion of the metal plate. One or more metal plates or metal foils of the connecting pieces to be connected are superimposed, and an ultrasonic welding horn is pressed onto the superposed metal plates or metal foils to thereby form a metal plate or a metal plate or metal foil. It is characterized in that the foil is welded and fixed.

According to the eighth aspect of the present invention, a convex portion is formed on the metal plate of the current collector, and the metal plate or the metal foil of the connection piece is superimposed on the convex portion, and the ultrasonic wave is applied from above. Since welding is performed, the welding energy is concentrated on the convex part, and the convex part is arranged on the fixed side with respect to the horn that vibrates ultrasonically, so when there are many metal plates and metal foils stacked on this Can be reliably welded.

According to a ninth aspect of the invention, there is provided a battery manufacturing method, wherein a convex portion is formed on a surface of one of two metal plates of a current collector connected to an electrode of a battery element, Between the plates, one or more metal plates or metal foils of the connecting pieces connected to the current collector are overlapped and inserted, and the metal on the side of the two metal plates of the current collector on which the convex portions are not formed is provided. By pressing an ultrasonic welding horn from the outer surface of the plate, the metal plate and the metal plate or the metal foil are welded and connected and fixed.

According to the ninth aspect of the present invention, a convex portion is formed on one metal plate of the current collector, and a metal plate or a metal foil of a connection piece is overlapped between the metal plate and the other metal plate. Since ultrasonic welding is performed from the other metal plate, the welding energy is concentrated on the convex portion, and the convex portion is arranged on one metal plate on the fixed side with respect to the other metal plate ultrasonically vibrated by the horn. Therefore, even when there are a large number of metal plates or metal foils stacked thereon, welding can be reliably performed.

According to a tenth aspect of the invention, there is provided a battery and a method of manufacturing the battery, wherein the convex portion has a shape having a narrower cross section toward the tip.

According to the tenth aspect of the present invention, since the convex portion has a tapered shape such as a hemispherical shape or a conical shape, the welding energy is concentrated on the top portion of the convex portion, and the welding is further ensured. can do.

[0030] The invention of a battery and a method of manufacturing a battery according to claim 11 is characterized in that the metal plate of the current collector is bent with the linearly formed groove between both sides of one surface inside. Features.

According to the eleventh aspect, when the current collector is bent and housed in the battery, the bending can be accurately and easily performed by the groove.

According to a twelfth aspect of the present invention, the groove formed in the metal plate of the current collector is a rectangular groove having a flat bottom surface and substantially vertical inner side surfaces on both sides thereof. In this case, a gentle radius surface is provided at a corner between the bottom surface and both inner side surfaces.

According to the twelfth aspect of the present invention, when the shape of the groove is rectangular and the corners are rounded, the stress can be dispersed and the crack is less likely to be generated when bent.

[0034]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 8 show a first embodiment of the present invention. FIG. 1 is a partially enlarged longitudinal sectional view showing a connection portion between a current collector and a terminal connecting piece of a lithium ion secondary battery. FIG. 2 is a partially enlarged perspective view showing a connection portion between the current collector and the terminal connection piece of the lithium ion secondary battery, and FIG. 3 is a partially enlarged vertical sectional view showing a process for connecting and fixing the current collector and the terminal connection piece. FIG. 4 is a partially enlarged longitudinal sectional view showing a pressing step by a punch for connecting and fixing the current collector and the terminal connection piece, and FIG. 5 is a side view showing a state where the fixed current collector and the terminal connection piece are bent. FIG. 6 is a partially enlarged longitudinal sectional view showing a pressing step by a punch for connecting and fixing the current collector and the terminal connection piece, and FIG. 7 is a push-up step by a pin for connecting and fixing the current collector and the terminal connection piece. FIG. 8 is a partially enlarged longitudinal sectional view, and FIG. 8 is a portion showing a groove of a bent portion of the current collector. It is a large perspective view. Components having the same functions as those of the conventional example shown in FIGS. 16 to 18 are denoted by the same reference numerals.

In this embodiment, a connection structure between current collectors 4 and 4 and terminal connection pieces 6 and 6 in a lithium ion secondary battery having a structure similar to that of a conventional example and a method of manufacturing the same will be described. As shown in FIG. 2, the current collectors 4, 4 and the terminal connection pieces 6, 6 are connected and fixed by overlapping the connection portions 4a, 6a with each other.

In the present embodiment, the connection between the current collector 4 and the terminal connecting piece 6 is fixed by press working. That is, first, as shown in FIG. 3, the connecting portion 6a of the terminal connecting piece 6 and the connecting portion 4a of the current collector 4 are overlapped. 3 to 6, the direction of the current collector 4 is rotated by 90 ° so that the current collector 4
Are shown in such a state that the connection portions 4a of FIG.
Below the connection portion 6a (back side) of the terminal connection piece 6,
A concave die 7 is arranged, and a convex punch 8 is arranged above (on the front side of) the connecting portion 4 a of the current collector 4. Die 7
Is a concave shape having an inner peripheral surface having a cylindrical shape. The concave shape is formed by combining divided pieces 7a, 7a divided into two along the axial direction. Each of the divided pieces 7a is installed so as to be slidable in the radial direction, and is urged by a spring (not shown) in a direction in which the divided pieces 7a are pushed together. A pin 7b is fitted into a lower portion of the inner peripheral surface of the die 7, and the upper surface of the pin 7b becomes a concave bottom surface. The punch 8 is a cylindrical convex having a diameter sufficiently smaller than the concave inner diameter of the die 7, and is moved up and down by a press device.

Next, as shown in FIG. 4, the punch 8 is lowered to press the connecting portion 4a of the current collector 4 from above. Then, the overlapped connecting portions 4a and 6a are pressed by the punch 8 and project downward in a cylindrical shape, and become the fastening portions 4b and 6b having a concave upper surface (front surface) and a convex lower surface (back surface). .
When the fastening portions 4b and 6b protrude downward as described above, they enter into the concave shape of the die 7 and the leading end thereof is
And spreads in the circumferential direction by pushing the divided pieces 7a, 7a to the left and right.
Is such that the convex tip part is wider than the base part, and the fastening part 6b of the connecting part 6a is concave and convex, and the tip part is wider than the base part. Then, when the punch 8 is pulled back, as shown in FIG. 1, the convex shape of the fastening portion 4b of the connecting portion 4a is closely fitted into the concave shape of the fastening portion 6b of the connecting portion 6a, and the current collection is performed. The body 4 and the terminal connection piece 6 are connected and fixed by caulking.

Connection part 4 between current collector 4 and terminal connection piece 6
As shown in FIG. 2, fastening portions 4b and 6b are simultaneously formed at two locations a and 6a by press working. Also,
The current collector 4 and the terminal connection piece 6 fixed and connected in this manner
As shown in FIG. 5, the cover plate 2 shown in FIG. 16 is disposed at a position directly above the upper end of the battery element 1 by bending each of the connection portions 4a and 6a so as to be horizontal. . When the battery element 1 is housed in a battery case (not shown), the cover plate 2 fits into the upper end opening of the battery case, and the inside of the cover plate 2 is sealed by welding around the cover plate 2. The lithium ion secondary battery is completed.

As described above, according to the present embodiment, the fastening portion 4b formed on the connecting portion 6a of the terminal connecting piece 6
The current collector 4 and the terminal connection piece 6 are connected and fixed by fitting and tightening the fastening portion 6b formed on the connection portion 4a of the current collector 4. Moreover, the fastening part 4
Since the tips of b and 6b are swelled, the current collector 4 and the terminal connecting piece 6 are firmly and firmly connected and fixed without peeling, and the contact resistance is extremely reduced. Therefore, even when the lithium ion secondary battery is increased in size and charged and discharged at a high rate, the voltage drop at the connection portions 4a and 6a does not increase. Further, since the connecting portions 4a and 6a are integrally formed with the fastening portions 4b and 6b by press working, not only the adhesion between the connecting portions 4a and 6a is increased, but also the size of the battery is increased. Even when these plate thicknesses are increased, processing becomes difficult.

In the above embodiment, the divided pieces 7a, 7
Although the pressing method using the die 7 divided into two a has been described, a pressing method as shown in FIGS. 6 and 7 can also be used. That is, first, the connection portion 6a of the terminal connection piece 6
And the connecting portion 4a of the current collector 4 are overlapped, and a concave die 7 is provided below the connecting portion 6a of the terminal connecting piece 6 (on the back side).
And a convex punch 8 is disposed above (on the front side of) the connecting portion 4 a of the current collector 4. The die 7 is a vertically movable concave type having an inner peripheral surface having a cylindrical through hole, and a pin 7b having a slightly smaller diameter is fitted inside the through hole so as to be vertically movable. The punch 8 is a cylindrical convex shape having a diameter sufficiently smaller than the inner diameter of the through hole of the die 7, and can be moved up and down inside a fixed block having a sufficiently wide bottom surface. To protrude. The punch 8, die 7, and pin 7b are
It is designed to move up and down by a press device.

When the die 7 and the punch 8 are arranged in this way, as shown in FIG. 6, the punch 8 is lowered to press the connecting portion 4a of the current collector 4 from above. Then, the connection portions 6a of the superposed terminal connection pieces 6 are both pushed downward, and the upper surface side (front surface side) becomes concave and the lower surface side (lower surface side) becomes convex fastening portions 4b, 6b. Protrude. When the fastening portions 4b and 6b protrude downward as described above,
It enters the inside of the through-hole of the die 7, and the tip portion contacts the upper surface of the pin 7b. Next, as shown in FIG.
Is lowered and the pin 7b is raised to push the punch 8 back, so that the fastening portions 4b and 6b come out of the through holes of the die 7, and the front end portion spreads in the peripheral direction. And
When the punch 8 is further pulled back, as shown in FIG. 1, the convex fastening portions 4 b, 6, each of which has a distal end portion wider than the base portion, are provided.
b is formed.

In the above embodiment, the case where the metal plate of the current collector 4 is bent as it is has been described.
As shown in FIG. 5, a groove 4d is formed on one surface of these metal plates so as to linearly connect both ends thereof, and the groove 4d is bent as an inner bent portion. Processing can be performed accurately and easily. Further, as shown in FIG. 8, the shape of the groove portion 4d is a rectangular groove having a flat bottom surface and substantially vertical inner surfaces on both sides thereof, and the groove is gentle at the corner between the bottom surface and both inner surfaces. By providing the radius, as in the case of a V-shaped groove or a rectangular groove having a corner, a crack is generated due to stress concentration on a corner at the time of bending, and the current collector 4 is cut or the bent portion is formed. It is possible to prevent the electrical resistance from becoming large. The thickness of the bottom surface of the groove 4 d is 6 times the thickness of the current collector 4.
Preferably, the thickness is 0% or less. However, unless the thickness of the bottom surface is at least 0.1 mm or more, the strength at the bent portion becomes too weak and the electric resistance becomes too large. Such a groove 4d can be easily formed by pressing the metal plate of the current collector 4 in advance. Further, it is preferable that the groove 4 d is formed in the bent portion of the terminal connection piece 6 in the same manner.

Further, in the above embodiment, the case where the current collector 4 and the metal plate of the terminal connection piece 6 are connected one by one has been described. However, even if one or both of them are two or more metal plates. Good. In this case, the current collector 4 and the metal plate of the terminal connection piece 6 may be overlapped with each other after being overlapped with each other, or different metal plates may be alternately overlapped with each other. In the above embodiment, the case where the current collector 4 is connected to the terminal connection piece 6 has been described. However, the current collector 4 may be directly connected and fixed to the connection portion of the metal plate of the terminal 3 itself, or the electrode of the battery element 1 may be connected. Can be connected and fixed as a connection piece using a lead or the like of a metal plate connected to the metal plate.

9 to 12 show a second embodiment of the present invention. FIG. 9 is a partially enlarged longitudinal sectional view showing a connection portion between a current collector and a terminal connecting piece of a lithium ion secondary battery. FIG.
0 is a partially enlarged longitudinal sectional view showing a process for connecting and fixing the current collector and the terminal connection piece, FIG. 11 is a partially enlarged longitudinal sectional view showing a caulking step for connecting and fixing the current collector and the terminal connection piece,
FIG. 12 is a partially enlarged longitudinal sectional view showing the current collector and the terminal connection piece which are connected and fixed. Components having the same functions as those of the first embodiment shown in FIGS. 1 to 8 are denoted by the same reference numerals.

In the present embodiment, a connection structure between the current collectors 4, 4 and the terminal connection pieces 6, 6 in a lithium ion secondary battery having the same structure as that of the first embodiment and a manufacturing method thereof will be described. 9 to 12 also show a state in which the direction is rotated by 90 ° so that the drawing is easy to see, and the connecting part 4 a of the current collector 4 is arranged on the connecting part 6 a of the terminal connecting piece 6.

In this embodiment, as shown in FIG. 9, first, three through holes 4c are formed in the connection portion 4a of the current collector 4, and three connection holes 6c of the terminal connection piece 6 are formed at the same intervals. The convex part 6c of the location is formed. Each through-hole 4c is connected to the connecting portion 4a.
It is a round hole that penetrates the upper and lower surfaces, but the upper portion is provided with a taper whose inner diameter increases toward the upper open end. Each convex part 6
c is a columnar projection projecting from the upper surface of the connecting portion 6a with a diameter slightly smaller than that of the through hole 4c. This projection 6c
Is formed by press working in this embodiment,
Although a concave depression pressed by a punch is formed on the lower surface of the connection portion 6a, such a depression may not occur when formed by another method.

The connecting portion 4a of the current collector 4 and the terminal connecting piece 6
As shown in FIG. 10, the connecting portions 6a are overlapped with the connecting portions 4a facing upward, and the projections 6c are fitted into the respective through holes 4c from below. In addition, a caulking jig 9 is disposed above the connection portions 4a and 6a which are overlapped with each other. The caulking jig 9 is a jig having a substantially inverted conical downward projection at the lower end, and is disposed at three locations for each through hole 4c and mounted on an eccentric press. By operating this eccentric press, the caulking jig 9 is lowered, and as shown in FIG. 11, the tips of the three projections are placed on the upper surface of the convex portion 6c fitted into each through hole 4c of the connection portion 4a. Press.
Then, since the protrusion of the caulking jig 9 presses the center of the upper surface of the convex portion 6c and spreads the upper portion around, the convex portion 6c comes into pressure contact with the inner peripheral surface of the through hole 4c, as shown in FIG. To
The connecting portions 4a, 6a of the current collector 4 and the terminal connecting pieces 6 are connected and fixed by caulking. Moreover, since the through-hole 4c has a tapered upper portion, the upper portion of the convex portion 6c spreads around the tapered portion.

As in the first embodiment, the current collector 4 and the terminal connection piece 6 are bent so that the connection portions 4a and 6a are horizontal, so that the cover plate 2 is connected to the upper end of the battery element 1. Place it directly above the head. When the battery element 1 is housed in a battery case (not shown), the cover plate 2 fits into the opening at the upper end of the battery case. The ion secondary battery is completed.

As described above, according to the present embodiment, the through hole 4c formed in the connection portion 4a of the current collector 4
The current collector 4 and the terminal connection piece 6 are fixedly connected by fitting and crimping the convex portion 6c formed on the connection portion 6a of the terminal connection piece 6. In addition, since the upper portion of the convex portion 6c spreads around and is securely pressed against the inner peripheral surface of the through hole 4c, the contact resistance becomes extremely small, and the lithium ion secondary battery is enlarged to perform high-rate charge / discharge. In some cases,
The voltage drop at the connection portions 4a and 6a does not increase. In addition, the upper portion of the convex portion 6c is provided with a through hole 4c.
And spreads along the circumference of the through hole, so that it becomes larger than the inner diameter of the lower part of the through hole 4c to prevent falling off.
The connection portion 6a of the terminal connection piece 6 is drawn toward and pressed against the connection portion 4a of the current collector 4 to increase the degree of adhesion and further reduce the contact resistance. Further, since these connecting portions 4a and 6a are caulked by the eccentric press by fitting the convex portions 6c into the through holes 4c formed in advance, even when these plate thicknesses are increased with the enlargement of the battery, Eliminating difficulties in processing is eliminated.

In the above embodiment, the case where a taper is provided above the through hole 4c has been described.
The entirety of c may be provided with a taper, or even a straight hole without a taper may provide a sufficiently secure connection and fixation. The through hole 4c does not necessarily have to be a round hole, but may have any shape. However, when the shape of the through hole 4c is not a round hole, it is preferable that the protrusion 6c also has a shape corresponding to this.

In the above embodiment, the through hole 4c is formed in the connecting portion 4a of the current collector 4, and the connecting portion 6 of the terminal connecting piece 6 is formed.
Although the case where the protrusion 6c is formed on the terminal a has been described, a through hole may be formed on the connection 6a of the terminal connection piece 6 and the protrusion may be formed on the connection 4a of the current collector 4. Furthermore, in the above embodiment, the case where the current collector 4 is connected to the terminal connection piece 6 has been described. However, the terminal 3 itself is provided with a through hole or a projection,
Here, the connection portion 4a of the current collector 4 may be directly connected and fixed, or a lead or the like connected to the electrode of the battery element 1 may be connected and fixed as a connection piece.

Further, in the above embodiment, the caulking jig 9
Is mounted on the eccentric press and caulked, but any other caulking method may be used as long as the tip of the convex portion 6c is pushed out to the periphery.

When the current collector 4 and the metal plate of the terminal connecting piece 6 are bent, similarly to the first embodiment shown in FIG. 8, a groove 4d is formed on one surface of these metal plates. Alternatively, the groove 4d can be bent as an inner bent portion.

Incidentally, Japanese Utility Model Laid-Open Publication No. Sho 61-16682 discloses a current collector provided with a plurality of perforations.
However, the perforation of the current collector is for connecting and fixing the cylindrical protruding edge to the end of the electrode of the battery element by welding, and the present invention in which a projection is fitted into the perforation and caulked. It is completely different from the configuration.

FIGS. 13 to 15 show a third embodiment of the present invention. FIG. 13 shows a state where a corrugated plate portion of a current collector is connected and fixed to a positive electrode of a battery element of a lithium ion secondary battery. FIG. 14 is a partially enlarged longitudinal sectional view showing a step of ultrasonically welding a large number of positive electrodes sandwiched between U-shaped portions of a corrugated plate portion of a current collector, and FIG. FIG. 4 is a partially enlarged longitudinal sectional view showing a step of ultrasonically welding a large number of positive electrodes to a current collector. The same reference numerals are given to constituent members having the same functions as those of the first and second embodiments shown in FIGS.

The present embodiment is different from the first and second embodiments in that the current collectors 4 and 4 of the lithium ion secondary battery have the same structure.
The connection structure of the positive electrode 4 and the positive and negative electrodes of the battery element 1 and a method of manufacturing the same will be described.

In this lithium ion secondary battery, for example, in the case of the positive electrode current collector 4, as shown in FIG. 13, the gap between two U-shaped portions of the corrugated plate portion 4 e formed on the current collector 4 A plurality of aluminum foils, which are uncoated portions of the active material of the positive electrode 1a protruding from the upper end surface of the battery element 1, are sandwiched by a plurality of pieces, and ultrasonic welding is performed from outside the U-shaped portion of the corrugated plate 4e. The connection between the positive electrode 1a and the current collector 4 is fixed. Similarly, in the case of the negative electrode current collector 4, similarly, a plurality of copper foils, which are active material uncoated portions of the negative electrode protruding from the lower end surface of the battery element 1, are provided in the U-shaped portion of the corrugated plate portion 4 e. And fixed by ultrasonic welding. In addition,
FIG. 13 shows a diagram in which only two positive electrodes 1a are sandwiched between each U-shaped portion of the corrugated plate portion 4e for simplicity of the drawing. The positive electrode 1a is sandwiched. The reason why the connection is fixed by ultrasonic welding is that resistance welding is difficult because the electrical resistance of aluminum or copper used as the current collectors 4, 4 and the electrodes of the positive and negative electrodes is low. However, in the conventional case, since the metal surfaces facing each other at the U-shaped portion of the corrugated plate portion 4e are flat, the energy of the ultrasonic welding is dispersed over a wide range of the large number of positive and negative electrodes sandwiched therebetween. Therefore, these electrodes could not be securely connected and fixed, and the welding became insufficient and the electric resistance increased, or some of the electrodes were peeled off due to peeling of the welded portions.

In this embodiment, in the case of the positive electrode current collector 4,
As shown in FIG. 14, a convex portion 4f is provided on the inner surface of one of the metal plates facing each other (the left side in the drawing) of each U-shaped portion of the corrugated plate portion 4e. The convex portion 4f is a hemispherical protrusion whose transverse cross section becomes narrower toward the projecting tip side, and is actually formed at three places along the width direction of the corrugated plate portion 4e. At the upper end of the positive electrode 1a of the battery element 1, a large number of one-sided linear portions wound into a long cylindrical shape are divided into two parts inside and outside the winding, and each of them is clamped by a jig. It is inserted into two U-shaped portions of the corrugated plate portion 4e. Then, of the metal plates facing each other at the U-shaped portion of the corrugated plate portion 4e, ultrasonic welding is performed by pressing the horn 10 of the ultrasonic welding machine against the outer side of the metal plate on which the convex portion 4f is not formed. . Then, the ultrasonic vibration of the horn 10 is transmitted to the large number of positive electrodes 1a via the other metal plate facing the U-shaped portion of the corrugated plate portion 4e. Moreover, in this case, since welding energy is concentrated near the convex portion 4f formed on one of the metal plates facing each other at the U-shaped portion, a region near the convex portion 4f in each positive electrode 1a receives a strong frictional force. It will be surely welded firmly.
Similarly, in the case of the negative electrode current collector 4, similarly, a convex portion 4 f is provided on one metal facing the U-shaped portion of the corrugated plate portion 4 e, and the horn 10 of the ultrasonic welding machine is provided from the outside of the other metal plate. , Ultrasonic welding is performed.

As described above, according to the present embodiment, the electrodes of the battery element 1 sandwiched between the U-shaped portions of the corrugated plate portion 4e of the current collector 4 are securely and firmly welded by the convex portions 4f. Therefore, there is no possibility that the connection between the electrode and the current collector 4 becomes insufficient or peels off and the electric resistance increases, and even when the lithium ion secondary battery is enlarged and high-rate charge / discharge is performed, The voltage drop does not increase.

Japanese Unexamined Patent Publication (Kokai) No. 56-45567 discloses a horn of an ultrasonic welding machine in which a cap-shaped projection is formed on the tip end surface of the horn, and the horn is used to ultrasonically weld the positive and negative electrodes to the current collector. The invention has been disclosed. However, such a cap-like projection is effective in reliably vibrating the current collector, but does not concentrate welding energy. This is clear from the fact that the invention disclosed in the publication aims at welding the projecting end of the electrode to a wide area of the current collector. Therefore, as in the present invention, it is not suitable for an application in which a current collector and a large number of electrodes are overlapped and ultrasonic welding is performed, and even if welding is actually performed using such a horn. There is no great difference from the conventional example. In addition, if a cap-like projection is formed on the tip end face of the tip of the horn, the cap-like projection will be worn as the ultrasonic welding operation is repeated, so that there is a problem that the chip must be replaced frequently. .

The projection 4f of the present embodiment is replaced with the corrugated plate 4
The horn 1 is formed on the inner side surface of the metal plate on the other side facing the U-shaped portion e and from the outside of the metal plate on which the projection 4f is formed.
Even when 0 was pressed, the electrodes of the battery element 1 could not be reliably welded as in the invention disclosed in the above-mentioned publication.

In the above embodiment, one current collector 4
Is bent to form a corrugated plate portion 4e, and an electrode is sandwiched between the U-shaped portions and welding is performed. Welding can also be performed by forming a convex portion 4f on the opposite surface of the current collector 4 and pressing the horn 10 from the outside of the other current collector 4. Further, as shown in FIG. 15, a projection 4f is formed on a flat surface of one current collector 4 and the projection 4f is formed.
An electrode may be overlapped on the surface where f is formed, and the horn 10 may be pressed from above the overlapping electrodes.

Further, in the above embodiment, the case where the connection piece connected to the metal plate of the current collector 4 is a metal foil of a plurality of electrodes has been described, but one metal foil can be connected and fixed. It is also possible to connect and fix a metal plate such as a lead connected to one or a plurality of electrodes as a connection piece. The connection piece is not limited to the electrode or the metal plate connected to the electrode, but may be the terminal 3 or the terminal connection piece 6 connected to the terminal 3.
It may be.

Further, in the above-described embodiment, the case where the convex portion 4f is a hemispherical projection has been described. However, other shapes such as a conical shape may be used as long as the cross section is narrower toward the distal end. Further, since the cross sections have the same shape such as a columnar shape and the effect of concentrating the welding energy on the projections 4f can be obtained to some extent, the shape need not necessarily be as narrow as the tip side.

[0066]

As is clear from the above description, according to the battery and the method for manufacturing the battery of the present invention, the connection pieces such as the terminal connection pieces and the electrodes of the battery element are securely and firmly connected to the current collector. Therefore, the battery performance does not deteriorate even in the case of high-rate charging and discharging.

[Brief description of the drawings]

FIG. 1 is a partially enlarged longitudinal sectional view showing a first embodiment of the present invention and showing a connection portion between a current collector and a terminal connection piece of a lithium ion secondary battery.

FIG. 2, showing the first embodiment of the present invention, is a partially enlarged perspective view illustrating a connection portion between a current collector and a terminal connection piece of a lithium ion secondary battery.

FIG. 3, showing the first embodiment of the present invention, is a partially enlarged longitudinal sectional view showing a process for connecting and fixing a current collector and a terminal connecting piece.

FIG. 4 is a partially enlarged longitudinal sectional view showing the first embodiment of the present invention and showing a pressing step by a punch for connecting and fixing a current collector and a terminal connecting piece.

FIG. 5, showing the first embodiment of the present invention, is a side view showing a state where a connected current collector and a terminal connection piece are bent.

FIG. 6 is a partially enlarged longitudinal sectional view showing the first embodiment of the present invention and showing a pressing step by a punch for connecting and fixing the current collector and the terminal connection piece.

FIG. 7 shows the first embodiment of the present invention, and is a partially enlarged longitudinal sectional view showing a step of pushing up by a pin for connecting and fixing a current collector and a terminal connecting piece.

FIG. 8 shows the first embodiment of the present invention, and is a partially enlarged perspective view showing a groove of a bent portion of a current collector.

FIG. 9 shows a second embodiment of the present invention, and is a partially enlarged longitudinal sectional view showing a connection portion between a current collector of a lithium ion secondary battery and a terminal connection piece.

FIG. 10 shows a second embodiment of the present invention,
FIG. 4 is a partially enlarged longitudinal sectional view showing a process for connecting and fixing a current collector and a terminal connection piece.

FIG. 11 shows a second embodiment of the present invention,
FIG. 9 is a partially enlarged longitudinal sectional view showing a caulking step for connecting and fixing the current collector and the terminal connection piece.

FIG. 12 shows a second embodiment of the present invention,
FIG. 4 is a partially enlarged longitudinal sectional view showing a current collector and terminal connection pieces that are connected and fixed.

FIG. 13 shows a third embodiment of the present invention,
FIG. 3 is a partial perspective view showing a state where a corrugated plate of a current collector is connected and fixed to a positive electrode of a battery element of a lithium ion secondary battery.

FIG. 14 shows a third embodiment of the present invention,
FIG. 9 is a partially enlarged longitudinal sectional view showing a step of ultrasonically welding a large number of positive electrodes sandwiched between U-shaped portions of a corrugated plate portion of a current collector.

FIG. 15 shows a third embodiment of the present invention,
FIG. 5 is a partially enlarged longitudinal sectional view showing a step of ultrasonically welding a large number of positive electrodes to a plate-shaped current collector.

FIG. 16 is an exploded perspective view showing a connection structure between a current collector and a terminal of a lithium ion secondary battery.

FIG. 17 is a perspective view showing a structure of a battery element of a lithium ion secondary battery.

FIG. 18 is a longitudinal sectional view showing a structure of a lid plate of the lithium ion secondary battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery element 1a Positive electrode 1b Negative electrode 3 Terminal 4 Current collector 4a Connecting part 4b Fastening part 4c Through hole 4d Groove part 4e Corrugated plate part 4f Convex part 6 Terminal connecting piece 6a Connection part 6b Fastening part 6c Convex part 7 Die 7a Division Piece 7b pin 8 punch 9 caulking jig 10 horn

Continued on the front page (72) Inventor Takeshi Shimozono Inosibaba-cho, Kichijoin, Minami-ku, Kyoto, Kyoto 1 Within Nippon Battery Co., Ltd. Nobaba-cho No.1 Japan Battery Co., Ltd. F-term (reference) 5H022 AA09 BB03 BB11 CC08 CC12 CC13 CC15 CC19 CC20 CC24

Claims (12)

[Claims] 1. A front surface formed on at least one metal plate of a current collector connected to an electrode of a battery element and at least one metal plate of a connection piece connected to the current collector. A battery characterized in that fastening portions having a concave shape and a convex shape on the back side are connected and fixed by fitting a convex shape having a distal end portion extending in a peripheral shape into a concave shape having an enlarged depth. 2. One or more metal plates of a current collector connected to an electrode of a battery element and one or more metal plates of a connecting piece connected to the current collector are overlapped with each other. A concave die whose inner peripheral surface can move around against the inward biasing force is placed on the back side of the metal plate, and the front side protrudes to the back side by pressing it with a convex punch. A method for manufacturing a battery, comprising: forming a fastening portion having a front end portion extending around the periphery thereof; and caulking and connecting these metal plates. 3. One or more metal plates of a current collector connected to the electrode of the battery element and one or more metal plates of connection pieces connected to the current collector, and The front side of the combined metal plate is pressed with a convex punch to form a fastening portion projecting to the back side, and then the front end of the fastening portion is pressed from the back side to spread the front end around. A method for manufacturing a battery, comprising connecting and fixing these metal plates by caulking. 4. A metal plate of a current collector connected to an electrode of a battery element and a metal plate of a connection piece connected to the current collector overlap with each other, and a through-hole formed on one of the metal plates. A battery characterized in that a protrusion formed on the other metal plate is fitted into the hole, and the tip of the protrusion spreads around and is caulked and fixed. 5. A through-hole is formed in one of a metal plate of a current collector connected to an electrode of a battery element and a metal plate of a connecting piece connected to the current collector, and the other metal is formed. A convex portion is formed on the plate, these metal plates are overlapped, and the convex portion of the other metal plate is fitted into the through hole of one metal plate,
A method for manufacturing a battery, characterized in that these metal plates are caulked and connected and fixed by pressing a tip end of a convex portion of the other metal plate fitted into a through-hole of one metal plate and spreading it around. 6. The through hole is a round hole, and a taper is formed at the end of the through hole opposite to the side where the projection is fitted, the inner diameter increasing toward the opening end. A battery or a method for manufacturing a battery according to claim 4. 7. At least one metal plate of a current collector connected to the electrode of the battery element and at least one metal plate or metal foil of a connection piece connected to the current collector A battery comprising: a plurality of current collectors which overlap on convex portions formed on metal plates, and wherein these metal plates and a metal plate or a metal foil are welded by ultrasonic welding and fixedly connected. 8. A convex portion is formed on a metal plate of a current collector connected to an electrode of a battery element, and one or more connection pieces connected to the current collector are formed on the convex portion of the metal plate. Welding these metal plates and metal plates or metal foils by connecting metal plates or metal foils together and pressing the ultrasonic welding horn on these superposed metal plates or metal foils to fix them together A method for producing a battery, comprising: 9. A current collector connected to an electrode of a battery element, a convex portion is formed on a surface of one of the two metal plates opposite to one of the metal plates, and connected to the current collector between the metal plates. One or more metal plates or metal foils of connection pieces to be connected are overlapped and inserted, and a horn for ultrasonic welding is formed from the outer surface of the two metal plates of the current collector on the side where the convex portion is not formed. And welding and fixing the metal plate and the metal plate or the metal foil by pressing against each other. 10. The method for producing a battery or a battery according to claim 7, wherein the projecting portion has a shape having a narrower cross section toward the tip. 11. The current collector according to claim 1, wherein the metal plate is bent with a groove formed linearly between both ends of one surface inside. , 5
10. The battery according to 6, 7, 8 or 9, or a method for producing the battery. 12. A groove formed in the metal plate of the current collector is a rectangular groove having a flat bottom surface and substantially vertical inner surfaces on both sides thereof, and a groove between the bottom surface and both inner surfaces. The method according to claim 11, wherein a rounded surface is provided at a corner.