JP2002231214A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery preventing metal foils of a positive electrode 1a and a negative electrode 1b from being exfoliated or fractured by using clamp boards 4 having board thickness optimal for ultrasonic welding. SOLUTION: This battery is so constituted that connecting parts 2a of a collector connector 2 connected to a terminal 3 are stacked to the metal foils of the positive electrode 1a and the negative electrode 1b projecting from the end face of a power generating element 1, then inserted between the clamp boards 4 and ultrasonic welded.

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 electrodes of a wound or laminated power generating element to a terminal through a current collector.

[0002]

2. Description of the Related Art FIG. 4 shows a configuration example of a large-sized lithium ion secondary battery used for an electric vehicle or the like. In this lithium ion secondary battery, four long cylindrical power generating elements 1 are closely arranged and connected in parallel. Each power generating element 1 is shown in FIG.
As shown in the figure, a positive electrode 1a and a negative electrode 1b are wound into a long cylindrical shape via a separator 1c. The positive electrode 1a carries a positive electrode active material on the surface of a strip-shaped aluminum foil 1d serving as an electrode substrate, and the negative electrode 1b carries a negative electrode active material on the surface of a band-shaped copper foil 1e serving as an electrode substrate. However,
Each of the positive electrode 1a and the negative electrode 1b is provided with an uncoated portion to which the active material is not applied at one side end of the strip, and the aluminum foil 1d and the copper foil 1e are exposed at the uncoated portion. ing. Then, these positive electrode 1a and negative electrode 1b
Is displaced in the opposite direction along the winding axis when the power generating element 1 is wound, so that only the aluminum foil 1d at the side end of the positive electrode 1a protrudes from one end surface of the long cylindrical shape, and the other end. Only the copper foil 1e at the side end of the negative electrode 1b protrudes from the end face of the negative electrode 1b.

[0003] As shown in FIG. 4, the four power generating elements 1 are arranged such that flat side surfaces of long cylinders are adjacent to each other. Then, the aluminum foil of the positive electrode 1a or the negative electrode 1b protruding from each of the power generating elements 1 is attached to the corrugated current collectors 2 arranged on both end faces of the power generating elements 1 respectively.
Copper foil is connected. The current collector 2
A flat metal plate is formed into corrugated irregularities, which are joined together at the ends thereof, and the terminal 3 is connected and fixed to the upper end of the joint. Then, the current collector connector 2 on the side of the positive electrode terminal 3 sandwiches the aluminum foil of the positive electrode 1a protruding from one end face of the power generating element 1 in each of the corrugated plate-shaped recesses, and is connected and fixed by ultrasonic welding. In the current collector connector 2 on the side 3, the copper foil of the negative electrode 1 b protruding from the other end face of the power generating element 1 is inserted into each corrugated concave portion, and connected and fixed by ultrasonic welding.

[0004] The four power generating elements 1 are housed in a battery case of a metal housing (not shown). At this time, the upper ends of the positive electrode terminal 3 and the negative electrode terminal 3 penetrate this battery case via an insulating sealing material and protrude to the outside. The battery case is filled with the electrolytic solution to form a lithium ion secondary battery.

[0005]

However, in the current collector 2 in the form of a corrugated sheet, it is necessary to increase the thickness of the metal plate to some extent so that a large current can easily flow during high-rate discharge. There is. Therefore, even when an aluminum foil or a copper foil is sandwiched in the corrugated concave portion of the current collecting connector 2 and ultrasonic welding is performed by applying an ultrasonic horn from the outside thereof, even if the ultrasonic welding is performed, since the thick metal plate is interposed, However, the aluminum foil and the copper foil are not sufficiently welded to each other, so that the aluminum foil and the copper foil are easily peeled off and the bonding strength is weakened. For this reason, when the output of the ultrasonic wave is increased, there arises a problem that the thin aluminum foil or copper foil of about 0.2 mm is torn and broken.

In addition, it is necessary to insert the aluminum foil or copper foil, which overlaps several times for each of the four power generating elements 1, simultaneously into each of the corrugated plate-shaped recesses to sandwich the current collector / connector 2. There was also a problem that workability at the time was poor.

The present invention has been made in order to cope with such a situation. The present invention is directed to a technique in which a current collecting connector is superimposed on an electrode substrate of a power generating element, which is sandwiched between thin sandwiching plates and connected and fixed by welding or the like. It is another object of the present invention to provide a battery in which the electrode substrate does not peel or break.

[0008]

According to a first aspect of the present invention, there is provided a battery, wherein a connection portion of a metal current collector connected to a terminal is superimposed on an electrode base projecting from an end face of a power generating element, and a metal holding plate is provided between the metal holding plates. It is characterized in that the electrode base and the connecting portion are sandwiched and welded or pressed.

According to the first aspect of the present invention, the connection portion of the current collector is superposed on the electrode base of the electrode of the power generation element, and this is sandwiched between the holding plates to perform welding or the like. The current passes through the connection part of the current collector, so that the cross-sectional area of this connection part can be increased to allow sufficient current to flow, and the holding plate has a thickness suitable for welding and crimping. The board can be used. For this reason,
The electrode base can be sufficiently securely welded to the connection part of the current collector and connected and fixed by using a thin holding plate that is optimal for ultrasonic welding, etc., and these electrode bases are broken. There is no danger of doing so. Conversely, if the thickness of the holding plate is made sufficiently thick, the connection portion between the electrode base and the current collecting connector can be securely pressed and fixed by pressing with a strong force from the outside of the holding plate. Will also be able to do it. Further, the electrode base may be sandwiched between the connecting portions of the current collecting connector by the holding plate, so that the assembling work is also facilitated.

According to a second aspect of the present invention, in the battery, the connection portion is a plate-shaped body.

According to the second aspect of the present invention, since the connecting portion is a plate bar, it is easy to be sandwiched between the holding plates, and by increasing the plate thickness, the current capacity can be sufficiently increased.

The battery according to a third aspect is characterized in that a projection is provided on a surface of the connection portion overlapping the electrode base.

According to the third aspect of the present invention, since the connecting portion is provided with the convex portion, the welding and crimping of the electrode base are concentrated on the convex portion, so that more reliable connection and fixing can be performed. .

The battery according to claim 4 is characterized in that the power generating element is of a long cylindrical winding type.

According to the fourth aspect of the present invention, even if the power generation element is of a wound type, it has a long cylindrical shape, so that the electrode base is curved and protrudes from the end face, and there is a portion which protrudes linearly. The connection portion and the holding plate can be easily welded and pressure-bonded to the shape-like portion.

The battery according to claim 5 is characterized in that the power generating element is housed inside the battery with its winding axis being in the horizontal direction.

According to the fifth aspect of the present invention, it is possible to provide a connection structure suitable for a battery in which a long cylindrical winding type power generating element is arranged sideways.

A battery according to a sixth aspect of the present invention is characterized in that the plurality of power generating elements are connected in parallel with their long cylindrical flat side faces adjacent to each other.

According to the sixth aspect of the present invention, it is possible to provide a connection structure suitable for a battery having flat side surfaces adjacent to each other by arranging a winding type power generating element having a long cylindrical shape sideways.

The battery according to claim 7 is characterized in that only the electrode base of the positive electrode protrudes from one end face of the power generating element and only the electrode base of the negative electrode protrudes from the other end face.

According to the seventh aspect of the present invention, since the electrode bases having different polarities protrude from both end faces of the power generating element, the connecting portions and the holding plates can also be arranged with the polarities separated, thereby facilitating the assembly.

[0022] The battery according to claim 8 is characterized in that one or more power generating elements have two or more connecting portions connected to the electrode base of the same polarity.

According to the eighth aspect of the present invention, since two or more connecting portions are arranged for each of the positive and negative electrode bases of each power generating element, they can be easily welded and crimped. In particular, in the case of a winding type power generating element having a long cylindrical shape, if two connecting portions are provided, the electrode base projecting linearly is divided into two portions around the winding axis. Can be arranged.

The battery according to a ninth aspect is characterized in that the holding plate is formed by bending a metal plate.

According to the ninth aspect of the present invention, since the holding plate has a simple configuration, it can be manufactured at low cost. Also,
When the connecting portion and the electrode base are sandwiched between the sandwiching plates, the bending angle can be widened, so that the assembling work can be facilitated.

[0026]

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

1 to 3 show an embodiment of the present invention. FIG. 1 is an assembled perspective view showing a connection structure between a power generating element and a terminal of a lithium ion secondary battery, and FIG. FIG. 3 is a cross-sectional view showing the connection portion of the current collector and the metal foils of the positive electrode and the negative electrode of the power generation element sandwiched between the terminals, and FIG. 3 shows a terminal block attached to a lid plate fixedly connected to a terminal of the lithium ion secondary battery. It is a perspective view showing a state. Components having the same functions as those of the conventional example shown in FIGS. 4 and 5 are denoted by the same reference numerals.

In the present embodiment, a large-sized lithium ion secondary battery used for an electric vehicle or the like will be described as in the conventional example. As shown in FIG. 1, this lithium-ion secondary battery has four long cylindrical power generating elements 1 closely arranged and connected in parallel. Each power generating element 1 has the same configuration as that of the conventional example. The aluminum foil at the side end of the positive electrode 1a protrudes from one end surface of the long cylindrical shape, and the copper foil at the side end of the negative electrode 1b protrudes from the other end surface. It protrudes.

The four power generating elements 1 are arranged in close contact with each other so that the flat cylindrical side surfaces thereof are in contact with each other. Is arranged. As for the current collection connector 2, the one arranged on one end face side of the power generation element 1 is made of an aluminum alloy plate, and the one arranged on the other end face is made of a copper alloy plate. Further, as these current collectors 2, metal plates having a certain thickness are used so that a large current at the time of high-rate discharge can sufficiently flow. Each of the current collectors 2 is a horizontally disposed metal plate having an approximately isosceles triangle shape, and has eight elongated connection portions 2a protruding downward from the bottom of the triangle. These connecting portions 2a are formed by punching a metal plate of the current collecting connector 2 into an elongated metal plate by pressing, and bending the metal plate downward,
° with a twist. Further, as shown in FIG. 2, a plurality of protrusions 2b protruding from one surface side of the metal plate are formed in these connection portions 2a.

The current collectors 2 are arranged above both ends of the four power generating elements 1, respectively, and the connecting portions 2 a are arranged on the end faces of these power generating elements 1. That is,
A current collector 2 made of an aluminum alloy plate is provided on an end surface of the power generating element 1 on the side where the aluminum foil protrudes from the positive electrode 1a.
Is arranged, and a current collector 2 made of a copper alloy plate is arranged on an end surface of the negative electrode 1 b on the side where the copper foil protrudes. Also, two connecting portions 2 a are arranged on each end face of each power generating element 1. Here, since the aluminum foil of the positive electrode 1a or the copper foil of the negative electrode 1b is wound on the end face of each power generating element 1 and protrudes into a long cylindrical shape, these metal foils are linearly bundled. The part is divided right and left around the winding axis. Then, the two connecting portions 2a arranged for each power generating element 1 are respectively arranged outside the bundle of metal foils divided into left and right. In addition, these two connecting portions 2a
As shown in FIG. 2, twists of 90 ° are applied in opposite directions so that the surface of the projecting side of the projection 2b faces the inside, that is, the bundle side of the metal foil.

In this manner, the connection portion 2a of the current collector 2
Is arranged, the bundle of the metal foils of the positive electrode 1a and the negative electrode 1b is sandwiched by the sandwiching plate 4 together with each connecting portion 2a. The holding plate 4 is formed by folding a strip-shaped metal plate in two along the longitudinal direction. In the case of the connection portion 2a on the positive electrode 1a side, an aluminum alloy plate is used, and the connection portion 2a on the negative electrode 1b side is used.
In this case, a copper alloy plate is used. Then, by performing ultrasonic welding from both sides of these holding plates 4, the connection portion 2 a of the current collector 2 sandwiched between the holding plates 4 and the bundle of the metal foils of the positive electrode 1 a and the negative electrode 1 b are joined. Weld. At this time, since the holding plate 4 is used only for welding and connecting the connecting portion 2a and the bundle of metal foils, it is preferable to use a metal plate which is thin to some extent so as to enable optimal ultrasonic welding. it can. The connection part 2a has a positive electrode 1a.
Since the convex portions 2b are formed on the surface overlapping the metal foil bundle of the negative electrode 1b and the negative electrode 1b, these metal foil bundles receive the energy of ultrasonic waves intensively at the convex portions 2b and are reliably welded. .

The approximately isosceles triangular portion of the positive / negative current collector 2 disposed above both ends of the power generating element 1 is shown in FIG.
As shown in (1), it is attached to both sides of the lower surface of the rectangular sealing plate 6 via the insulating sealing material 5. The sealing plate 6 is made of a stainless steel plate, and the positive and negative terminals 3 are arranged on both sides of the upper surface via another insulating sealing material 7. These terminals 3 are connected and fixed by crimping to the vicinity of the approximately isosceles triangular vertex of each current collector 2 through the sealing plate 6 at the lower end. The upper ends of these terminals 3 are connected and fixed by crimping to a terminal block 8 which locks terminal bolts 9 arranged on the insulating sealing material 7. These terminals 3 are made of an aluminum alloy for the current collector 2 made of an aluminum alloy plate, and made of a copper alloy for the current collector 2 made of a copper alloy plate. However, since the terminal block 8 and the terminal bolt 9 do not touch the electrolytic solution,
Steel or iron alloys having higher strength than these aluminum alloys and copper alloys are used. The insulating sealing materials 5 and 7 are arranged above and below the sealing plate 6, and are resin molded plates that insulate and seal between the current collector 2, the terminal 3, the terminal block 8, the terminal bolt 9 and the sealing plate 6. It is.

The four power generating elements 1 are housed in a battery case of a stainless steel case (not shown),
Is fitted into the upper end opening of the battery case and fixed by welding. Then, by filling the inside of the battery case with the non-aqueous electrolyte, a lithium ion secondary battery is obtained.

According to the lithium ion secondary battery having the above-described structure, the charging / discharging current between the positive electrode 1a or the negative electrode 1b of each power generating element 1 and the terminal 3 is limited to the current collecting connector 2 made of a thick metal plate. Flows through the connecting portion 2a, so that a sufficiently large charge / discharge current can flow. Moreover,
The bundle of the metal foils of the positive electrode 1a and the negative electrode 1b of each power generating element 1 is connected to the connecting portion 2a via a holding plate 4 made of a metal plate having a certain thickness.
Since the ultrasonic welding is performed, the welding is reliably performed, and the metal foil does not easily come off. In addition, since the energy due to the ultrasonic welding can be concentrated on the protrusion 2b of the connection portion 2a, the bundle of metal foil can be more securely and firmly welded to the connection portion 2a. Furthermore, each connection part 2a is arranged on the side of the bundle of metal foils of the positive electrode 1a and the negative electrode 1b protruding from the end face of the power generation element 1,
Since the connection portion 2a and the bundle of the metal foils may be inserted between the holding plates 4 in order, the bundle of the metal foils may be inserted into the corrugated concave portions of the current collector 2 as in the related art. The assembly operation can be performed more easily than the insertion operation.

According to the lithium ion secondary battery, the terminal 3 made of an aluminum alloy or a copper alloy is fixedly connected to a terminal block 8 made of an alloy of steel or iron, and the terminal 3 is connected to an external circuit. Since the connection is performed via the terminal bolt 9 locked to the base 8, there is no need to directly screw the terminal 3 made of an aluminum alloy or a copper alloy to connect the terminal 3 with a weak strength. Of the terminal 3 or deformation of the terminal 3 due to vibration or impact.

In the above embodiment, the case where the connecting portion 2a and the metal foil of the positive electrode 1a or the negative electrode 1b are welded between the holding plates 4 by ultrasonic welding has been described. Welding can also be performed. Further, instead of such welding, the connection portion 2a and the metal foil of the positive electrode 1a or the negative electrode 1b can be pressed by pressing with a strong force from the outside of the holding plate 4. In this case, unlike the case of welding, it is necessary to use a metal plate having a relatively large thickness, so that the connecting portion 2a and the metal foil can be securely pressed and held during this time. Further, in the above embodiment, the case where the convex portion 2b is formed in the connection portion 2a has been described, but a similar convex portion may be formed in the holding plate 4. However, even when such a convex portion 2b is not formed at all, the metal foil can be reliably welded or pressed.

In the above embodiment, the case where the metal foil of the positive electrode 1a or the negative electrode 1b is arranged only on one side of the connecting portion 2a has been described. It can also be sandwiched between. Further, in the above-described embodiment, two end faces of each power generation element 1 are provided.
Although the two connecting portions 2a are arranged, the number of the connecting portions 2a is not limited. For example, one connecting portion 2a may be arranged on one end face of each power generating element 1, or a metal foil protruding from the end faces of two power generating elements 1 adjacent to this one connecting portion 2a may be used. Common welding or crimping is also possible.

In the above-described embodiment, the wound cylindrical power generating element 1 has been described. However, in the case of the laminated power generating element 1, the metal of the positive electrode 1a and the negative electrode 1b protruding from the end face of the lamination is also used. The foil can likewise be connected and fixed. Further, in the above embodiment, the lithium ion secondary battery has been described, but the type of the battery does not matter.

[0039]

As is clear from the above description, according to the battery of the present invention, the current between the electrode and the terminal of the power generating element mainly passes through the connection portion of the current collector. In addition, the electrode base can be connected and fixed to the connection portion of the current collector / connector with sufficient reliability by using a thin holding plate that is optimal for welding and pressure bonding.

[Brief description of the drawings]

FIG. 1, showing an embodiment of the present invention, is an assembled perspective view showing a connection structure between a power generation element and a terminal of a lithium ion secondary battery.

FIG. 2, showing an embodiment of the present invention, is a cross-sectional view showing a connection portion of a current collector and a metal foil of a positive electrode and a negative electrode of a power generation element sandwiched between clamping plates.

FIG. 3 illustrates one embodiment of the present invention, and is a perspective view illustrating a state where a terminal block attached to a lid plate is connected and fixed to a terminal of a lithium ion secondary battery.

FIG. 4 is an exploded perspective view showing a conventional example and showing a connection structure between a power generation element and a terminal of a lithium ion secondary battery.

FIG. 5 is a perspective view showing a conventional example, and is an assembled perspective view showing a structure of a power generating element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power generation element 1a Positive electrode 1b Negative electrode 2 Current collector 2a Connection part 2b Convex part 3 Terminal 4 Clamping plate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Taketo Matsubara 1 in Kichijoin Nishinosho Inomaba-cho, Minami-ku, Kyoto-shi, Kyoto Inside Nippon Battery Co., Ltd. (72) Inventor Takeyoshi Konaga Minami-ku, Kyoto-shi Kichijoin Nishinosho Inono Babacho No. 1 Japan Battery Co., Ltd. F term (reference) 5H022 AA09 BB02 BB03 BB17 CC04 CC12 CC13 CC20 CC23 EE01 5H029 AJ11 AJ12 AJ14 BJ02 BJ14 CJ03 CJ05 DJ05 DJ12 DJ14 EJ01 HJ00 AJ12 A040 AT01 AY01 CC11 DD03 DD13 DD24 JJ02 JJ03 NN00 NN03

Claims (9)

[Claims] 1. A connecting portion of a metal current collector connected to a terminal is superimposed on an electrode substrate protruding from an end face of a power generating element, and the electrode substrate and the connecting portion are sandwiched between metal holding plates to be welded. A battery characterized by being crimped. 2. The battery according to claim 1, wherein the connecting portion is a plate-shaped body. 3. The battery according to claim 1, wherein a protrusion is provided on a surface of the connection portion overlapping the electrode base. 4. The battery according to claim 1, wherein the power generating element is a long cylindrical wound type. 5. The battery according to claim 4, wherein the power generation element is housed inside the battery with its winding axis being in the horizontal direction. 6. The battery according to claim 4, wherein the plurality of power generating elements are connected in parallel such that long cylindrical flat side faces are adjacent to each other. 7. The power generating element according to claim 1, wherein only the electrode base of the positive electrode protrudes from one end face of the power generating element, and only the electrode base of the negative electrode protrudes from the other end face.
7. The battery according to 3, 4, 5 or 6. 8. The method according to claim 1, wherein the number of connecting portions connected to the same polarity electrode base of one power generating element is two or more.
The battery according to claim 1, 2, 3, 4, 5, 6, or 7. 9. The method according to claim 1, wherein the holding plate is formed by bending a metal plate.
The battery according to 3, 4, 5, 6, 7, or 8.