JP5157027B2 - battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a battery in which an electrode of a laminated or wound power generation element is connected to a terminal via a current collector connection body.
[0002]
[Prior art]
A configuration example of a large-sized lithium ion secondary battery used for an electric vehicle or the like is shown in FIG. In this lithium ion secondary battery, four long cylindrical power generation elements 1 are arranged in close contact and connected in parallel. As shown in FIG. 5, each power generation element 1 is obtained by winding a positive electrode 1a and a negative electrode 1b 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 strip-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 where no active material is applied on one side end portion of the belt-like shape, and the aluminum foil 1d and the copper foil 1e are exposed at the uncoated portion. I am doing so. When the power generation element 1 is wound, the positive electrode 1a and the negative electrode 1b are shifted in opposite directions along the winding axis, so that one end surface of the long cylindrical shape has a side end portion of the positive electrode 1a. Only the aluminum foil 1d protrudes, and only the copper foil 1e at the side end of the negative electrode 1b protrudes from the other end face.
[0003]
As shown in FIG. 4, the four power generation elements 1 are arranged such that the long cylindrical flat side surfaces are adjacent to each other. And the aluminum foil of the positive electrode 1a and the copper foil of the negative electrode 1b which protruded from each electric power generation element 1 are connected to the corrugated current collection connection body 2 arrange | positioned at the both end surface parts of these electric power generation elements 1, respectively. ing. The current collector connection body 2 is formed by forming a metal flat plate into corrugated plate-shaped irregularities, aligning the two at the end portions, and connecting and fixing the terminals 3 to the upper ends of the mating portions. 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 corrugated concave portion, and is connected and fixed by ultrasonic welding. The current collector connection body 2 on the 3 side is connected and fixed by ultrasonic welding by inserting a copper foil of the negative electrode 1b protruding from the other end face of the power generating element 1 into each corrugated concave portion.
[0004]
The four power generation elements 1 are accommodated in a battery case having a metal casing (not shown). At this time, the upper end portions of the positive electrode terminal 3 and the negative electrode terminal 3 pass through the battery case via an insulating sealing material and protrude to the outside. A lithium ion secondary battery is obtained by filling the inside of the battery case with an electrolytic solution.
[0005]
[Problems to be solved by the invention]
However, in the corrugated plate-like current collector connector 2, it is necessary to increase the thickness of the metal plate to some extent so that a large current flows easily during high-rate discharge or the like. Therefore, even if an aluminum foil or a copper foil is sandwiched between the corrugated concave portions of the current collector connection body 2 and ultrasonic welding is performed by applying an ultrasonic horn from the outside, the thick metal plates are used. However, the aluminum foil and copper foil were not sufficiently welded, and the problem was that bonding strength was weakened due to easy peeling. For this reason, when the output of the ultrasonic wave is increased, there arises a problem that a thin aluminum foil or copper foil of about 0.2 mm is torn and broken.
[0006]
Moreover, it is necessary for the current collector connection body 2 to insert and sandwich aluminum foils and copper foils that overlap each other for each of the four power generating elements 1 into the corrugated concave portions at the same time. There was also a problem that the nature was bad.
[0007]
The present invention has been made in order to cope with such a situation, and an electrode base body is obtained by sandwiching a current-carrying connection body on an electrode base body of a power generation element and sandwiching it between thin sandwich plates and fixing them by welding or the like. An object of the present invention is to provide a battery that does not peel off or break.
[0008]
[Means for Solving the Problems]
The battery of claim 1 is a stacked type or a wound type, and includes a power generation element in which an electrode base protrudes from an end surface.
A metal clamping plate for sandwiching the electrode substrate;
A metal current collector connection connected to the electrode terminal,
The metal current collector connection body has a plate bar-shaped connection portion,
The plate bar-like connecting portion is disposed so that only one side thereof faces the electrode substrate,
The electrode base, the metal sandwich plate and the connection portion are welded or pressure-bonded ,
The electrode substrate protrudes as a bundle of laminated metal foils,
The metal holding plate covers the edge of the bundle of the electrode base and the side surface of the plate bar-like connecting portion .
[0009]
According to the first aspect of the present invention, the connection part of the current collector connection member is disposed to face only one side of the electrode base of the electrode of the power generation element, and this is laminated with the sandwiching plate to perform welding or the like. The current mainly passes through the connection part of the current collector connection body, and the cross-sectional area of this connection part can be increased so that sufficient current flows, and the sandwich plate is suitable for welding and crimping. A metal plate having a thickness can be used. For this reason, it becomes possible to weld and fix the electrode base to the connection part of the current collector connector sufficiently and securely using a sandwich plate having a thin thickness optimum for ultrasonic welding or the like. There is no risk of the substrate breaking. On the other hand, if the thickness of the clamping plate is made sufficiently thick, the connection portion between the electrode base and the current collector connector is securely crimped and fixed by pressing with a strong force from the outside of the clamping plate. You will also be able to. Furthermore, since the electrode substrate may be sandwiched by a sandwiching plate for each connection portion of the current collector connector, assembly work is facilitated.
In addition, since the power generating element is a laminated type or a wound type, there is a part protruding linearly in addition to the electrode base being curved and protruding from the end face, and the connecting part and the clamping plate are easily welded to the linear part. Can be crimped.
In addition, it is possible to provide a connection structure suitable for a battery in which power generation elements are disposed sideways, for example, and flat side surfaces are adjacent to each other.
Furthermore, since the electrode bases having different polarities protrude from the both end faces of the power generation element, the connecting portions and the sandwiching plates can be arranged with the polarities separated, and assembly is facilitated.
Furthermore, since the connecting portion is in the form of a plate bar, it is easy to be sandwiched between the sandwiching plates, and the current capacity can be sufficiently increased by increasing the plate thickness.
Furthermore, it becomes possible to securely and firmly bond or crimp the connecting portion and the electrode substrate.
[0012]
The battery according to claim 2 is characterized in that a convex portion is provided on a surface of the connection portion that overlaps the electrode substrate.
[0013]
According to the second aspect of the present invention, since the convex portion is provided in the connecting portion, welding and crimping of the electrode base can be concentrated on the convex portion, so that more reliable connection and fixing can be performed.
[0014]
[0015]
[0016]
The battery according to claim 3 is characterized in that the power generating element is of a winding type and is housed inside the battery with its winding axis in the horizontal direction.
[0017]
According to the invention of claim 3 , it is possible to provide a connection structure suitable for a battery in which long cylindrical wound-type power generating elements are disposed sideways.
[0018]
[0019]
[0020]
[0021]
[0022]
The battery according to claim 4 is characterized in that there are two or more connecting portions connected to the electrode base of the same polarity of one power generation element.
[0023]
According to the fourth 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, it is possible to easily weld and crimp them. In particular, in the case of a long cylindrical winding type power generation element, if two such connecting portions are provided, the electrode base projecting in a straight line is divided into two locations around the winding axis. Can be arranged.
[0024]
The battery according to claim 5 is characterized in that the metal holding plate is formed by bending a metal plate.
[0025]
According to invention of Claim 5 , since a clamping board is a simple structure, it can manufacture at low cost. In addition, when the connecting portion or the electrode substrate is sandwiched between the sandwiching plates, the bending angle can be widened, so that the assembling work can be facilitated.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0027]
1 to 3 show an embodiment of the present invention. FIG. 1 is an assembled perspective view showing a connection structure between a power generation element and a terminal of a lithium ion secondary battery, and FIG. 2 is sandwiched between sandwiching plates. FIG. 3 shows a state where a terminal block attached to a cover plate is connected and fixed to a terminal of a lithium ion secondary battery. It is a perspective view. In addition, the same number is attached | subjected to the structural member which has the same function as the prior art example shown in FIGS.
[0028]
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 is a battery in which four long cylindrical power generation elements 1 are in close contact and connected in parallel. Each power generating element 1 has the same configuration as that of the conventional example, and 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 from the other end surface. Has come to protrude.
[0029]
The four power generating elements 1 are arranged in close contact with each other so that the flat cylindrical flat side surfaces are in contact with each other, and the connection portions 2a of the current collector connection bodies 2 are disposed on both end surfaces of the power generating elements 1, respectively. The The current collector connector 2 is arranged on one end face side of the power generating element 1 from an aluminum alloy plate, and the one arranged on the other end face side is made of a copper alloy plate. In addition, these current collector connectors 2 are made of a metal plate that is thick to some extent so that a large current during high rate discharge can sufficiently flow. These current collector connection bodies 2 are metal plates arranged in an approximately isosceles triangle shape horizontally, and eight elongated connection portions 2a project from the bottom of the triangle shape downward. These connecting portions 2a are obtained by punching a metal plate of the current collector connection body 2 into a long and narrow metal plate shape by pressing, and bending it downward and adding a twist of 90 °. Further, as shown in FIG. 2, a plurality of convex portions 2b projecting to one surface side of the metal plate are formed in these connection portions 2a.
[0030]
The current collector connection body 2 is arranged above both end portions of the four power generation elements 1, and the connection portion 2 a is arranged on the end face portions of these power generation elements 1. That is, the current collector connector 2 made of an aluminum alloy plate is disposed on the end surface portion of the power generation element 1 on the side where the aluminum foil protrudes, and the end surface portion of the negative electrode 1b on the side where the copper foil protrudes is formed on the copper alloy. A current collector connector 2 made of a plate is disposed. Two connecting portions 2 a are arranged on the 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 around the end face of each power generating element 1, the metal foil is bundled in a straight line. The part is divided into right and left around the winding axis. And the two connection parts 2a arrange | positioned for every electric power generation element 1 are each arrange | positioned on the outer side of the bundle | flux of these metal foils divided into right and left. In addition, as shown in FIG. 2, these two connecting portions 2a have twists of 90 ° in opposite directions so that the protruding side surface of the convex portion 2b faces the inside, that is, the bundle side of the metal foil. It has been added.
[0031]
Thus, when the connection part 2a of the current collector connection body 2 is arranged, the sandwiching plate 4 sandwiches the bundle of metal foils of the positive electrode 1a and the negative electrode 1b together with each connection part 2a. The sandwiching plate 4 is formed by folding a strip-shaped metal plate in half along the longitudinal direction. In the case of the connecting portion 2a on the positive electrode 1a side, an aluminum alloy plate is used, and the connecting portion 2a on the negative electrode 1b side is used. In this case, a copper alloy plate is used. And by performing ultrasonic welding from both sides of these clamping plates 4, the connection part 2a of the current collector connection body 2 sandwiched between the respective clamping plates 4 and a bundle of metal foils of the positive electrode 1a and the negative electrode 1b are obtained. Weld. At this time, since the sandwiching plate 4 is used only for welding and fixing the connection portion 2a and the bundle of metal foils, it is necessary to use a metal plate that is thin to some extent so that optimum ultrasonic welding is possible. it can. Moreover, since the convex part 2b is formed in the connection part 2a in the surface which overlaps with the bundle | flux of the metal foil of the positive electrode 1a or the negative electrode 1b, the bundle | flux of these metal foil concentrates the energy of an ultrasonic wave in the convex part 2b. Will be surely welded.
[0032]
The substantially isosceles triangular portion of the positive and negative current collector connection body 2 disposed above both ends of the power generation element 1 is formed of a rectangular sealing plate 6 via an insulating sealing material 5 as shown in FIG. Mounted on both sides of the bottom surface. The sealing plate 6 is made of a stainless steel plate, and 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 caulking in the vicinity of the apexes of an isosceles triangle shape of each current collector connection body 2 through the sealing plate 6 at the lower end. Further, the upper end portions of these terminals 3 are connected and fixed by caulking to a terminal block 8 that locks terminal bolts 9 arranged on the insulating sealing material 7. These terminals 3 are made of aluminum alloy for the current collector connection 2 made of an aluminum alloy plate, and made of copper alloy for the current collector connection 2 made of a copper alloy plate. However, since the terminal block 8 and the terminal bolt 9 do not come into contact with the electrolytic solution, steel, iron alloy, or the like having higher strength than these aluminum alloys and copper alloys is used. Insulating sealing materials 5 and 7 are resin molded plates that are arranged above and below the sealing plate 6 to insulate and seal the current collector connector 2, the terminal 3, the terminal block 8, and the terminal bolt 9 and the sealing plate 6. It is.
[0033]
The four power generating elements 1 are housed in a battery case of a stainless steel casing (not shown), and a sealing plate 6 is fitted into the upper end opening of the battery case and fixed by welding. And the inside of this battery case is filled with a non-aqueous electrolyte so that a lithium ion secondary battery is obtained.
[0034]
According to the lithium ion secondary battery having the above-described configuration, the charging / discharging current between the positive electrode 1a or the negative electrode 1b of each power generation element 1 and the terminal 3 is a connection portion of the current collector connection body 2 that is formed of a thick metal plate. Since it flows through 2a, it becomes possible to flow a sufficiently large charge / discharge current. Moreover, the bundles of the metal foils of the positive electrode 1a and the negative electrode 1b of each power generation element 1 are ultrasonically welded to the connection portion 2a via the sandwiching plate 4 made of a metal plate that is thin to some extent, so that the welding is performed reliably. Is not easily peeled off. Moreover, since the energy by this ultrasonic welding can be concentrated on the convex part 2b of the connection part 2a, the bundle of metal foil can be more reliably and firmly welded to the connection part 2a. Furthermore, each connection part 2a is arrange | positioned at the side part of the bundle | flux of the metal foil of the positive electrode 1a and the negative electrode 1b which protruded from the end surface of the electric power generation element 1, and between these clamping parts 4 in order of these connection parts 2a and metal foil bundles Therefore, the assembly work can be easily performed as compared with the work of inserting the bundle of these metal foils into the corrugated concave portions of the current collector connection body 2 as in the prior art. become.
[0035]
Further, according to the lithium ion secondary battery, the terminal 3 made of aluminum alloy or copper alloy is connected and fixed to the terminal block 8 made of an alloy of steel or iron, etc., and the connection with the external circuit is connected to the terminal block 8. Since it is performed via the terminal bolt 9 that is locked, it is not necessary to directly connect the terminal 3 made of weak aluminum alloy or copper alloy by screwing, and the terminal 3 is damaged by tightening the screwing. Or the terminal 3 may be deformed by vibration or shock.
[0036]
In addition, although the said embodiment demonstrated the case where the connection part 2a and the metal foil of the positive electrode 1a and the negative electrode 1b were welded between the clamping plates 4 by ultrasonic welding, it welds by other weldings, such as spot welding. You can also. Moreover, it replaces with such welding and it can also crimp | bond the connection part 2a and the metal foil of the positive electrode 1a or the negative electrode 1b by pressing with a strong force from the outer side of the clamping board 4. FIG. In this case, unlike the case of welding, it is necessary to use a metal plate that is thick to some extent so that the connecting portion 2a and the metal foil can be securely pressed and held therebetween. Furthermore, although the said embodiment demonstrated the case where the convex part 2b was formed in the connection part 2a, the same convex part can also be formed in the clamping board 4. FIG. But even when such a convex part 2b is not formed at all, metal foil can be reliably welded or crimped | bonded.
[0037]
In the above embodiment, the case where the metal foil of the positive electrode 1a and the negative electrode 1b is disposed only on one side of the connecting portion 2a has been described. However, the metal foil is disposed on both sides and is sandwiched between the sandwiching plates 4. It can also be. Furthermore, in the said embodiment, although the two connection parts 2a were arrange | positioned in the one end surface of each electric power generation element 1, the arrangement | positioning number of this connection part 2a is not limited. For example, one connecting portion 2a may be disposed on one end face of each power generating element 1, or metal foils protruding from the end faces of two power generating elements 1 adjacent to the one connecting portion 2a may be used. Common welding or pressure bonding can also be performed.
[0038]
In the above embodiment has described the lithium ion secondary battery, regardless the type of battery.
[0039]
【Effect of the invention】
As is apparent from the above description, according to the battery of the present invention, the current between the electrode of the power generation element and the terminal mainly passes only on one side of the plate-bar-like connection portion of the current collector connection body. Therefore, it becomes possible to connect and fix the electrode base to the connection portion of the current collector connector with sufficient reliability by using a sandwich plate having a thin plate thickness optimum for welding and pressure bonding.
[Brief description of the drawings]
FIG. 1 is an assembled perspective view showing a connection structure between a power generation element and a terminal of a lithium ion secondary battery according to an embodiment of the present invention.
FIG. 2, showing an embodiment of the present invention, is a cross-sectional view showing a connection part of a current collector connection member sandwiched between sandwiching plates and a metal foil of a positive electrode or a negative electrode of a power generation element.
FIG. 3, showing an embodiment of the present invention, is a perspective view showing a state in which a terminal block attached to a cover plate is connected and fixed to a terminal of a lithium ion secondary battery.
FIG. 4 is an exploded perspective view showing a connection structure between a power generation element and a terminal of a lithium ion secondary battery according to a conventional example.
FIG. 5 is an assembled perspective view showing a structure of a power generation element, showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Power generation element 1a Positive electrode 1b Negative electrode 2 Current collection connector 2a Connection part 2b Convex part 3 Terminal 4 Clamping plate

Claims (5)

In a battery having a power generation element that is a laminated type or a wound type, and an electrode substrate protrudes from an end face,
A metal clamping plate for sandwiching the electrode substrate;
A metal current collector connection connected to the electrode terminal,
The metal current collector connection body has a plate bar-shaped connection portion,
The plate bar-like connecting portion is disposed so that only one side thereof faces the electrode substrate,
The electrode base, the metal sandwich plate and the connection portion are welded or pressure-bonded ,
The electrode substrate protrudes as a bundle of laminated metal foils,
The battery , wherein the metal holding plate covers an edge of the bundle of the electrode base and a side surface of the plate-bar-like connecting portion . The battery according to claim 1, wherein a convex portion is provided on a surface of the connection portion that overlaps the electrode substrate. The battery according to claim 1 or 2, wherein the power generation element is of a winding type and is housed inside the battery with a winding axis in a horizontal line direction. The battery according to any one of claims 1 to 3 , wherein the number of the connecting portions connected to the electrode base of the same polarity of one power generation element is two or more. The battery according to any one of claims 1 to 4 , wherein the metal sandwich plate is formed by bending a metal plate.

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