JP2000340210A - Electrical energy storing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrical energy storing device with a sealing plate 11 fixed on an opening part of a bottomed metal negative electrode can 1 and a wound electrode body 2 provided inside capable of reducing the number of parts and weight. SOLUTION: This electrical energy storing device includes a plurality of projected parts 15 projected to a side of a wound electrode body 2 integrally formed on a bottom part of a negative electrode can 1, and a plurality of current collector parts 5 respectively formed on end parts of a positive electrode 21 and a negative electrode 23 of the wound electrode body 2. Each of the projected parts 15 of the negative electrode can 1 is laser-welded to each of the current collector parts 5 of the negative electrode 23. At least one of the end parts of the electrodes is directly welded to the projected part integrally formed on the bottom part of the battery can, and a conventional current collector member is not interposed between the electrode and the electrode can. Therefore, the number of parts and the weight can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric double layer capacitor and a lithium ion secondary battery which are used as a power source for an igniter of a gasoline vehicle or a storage device for storing regenerative braking energy of a hybrid vehicle or an electric vehicle. And the like regarding the structure of an electric energy storage device.

[0002]

2. Description of the Related Art In a conventional lithium ion secondary battery, for example, as shown in FIG. 10, a wound electrode body (2) is housed inside a negative electrode can (1), and an opening of the negative electrode can (1) is opened. A sealing plate (11) is fixed to the sealing member, and an insulating member (12) is interposed between the negative electrode can (1) and the sealing plate (11). Also, on the sealing plate (11),
A positive terminal (13) incorporating a safety valve (14) is attached. Thereby, the electric power generated by the winding electrode body (2) can be taken out from the positive electrode terminal (13) and the negative electrode can (1).

The wound electrode body (2) comprises a strip-shaped positive electrode (21), a separator (22) and a negative electrode (23). The positive electrode (21) is prepared by applying a positive electrode active material (24) to the surface of a core made of aluminum foil, and the negative electrode (23) is coated with the negative electrode active material (26) on the surface of a core made of copper foil. It is produced by coating. The positive electrode (21) and the negative electrode (23) are each a separator (22)
The sheets are superposed on each other while being shifted in the width direction, and are wound in a spiral shape. Accordingly, at one end of the two ends in the axial direction of the winding electrode body (2), the edge of the positive electrode (21) projects outward from the edge of the separator (22), and the other end. At the end of the negative electrode outward from the edge of the separator (22)
The edge of (23) protrudes.

[0004] Current collecting members (3) are provided at both ends of the wound electrode body (2). Current collecting member (3)
Is a flat plate part (33) joined to the end face of the winding electrode body (2).
And a tab portion (32) protruding from the surface of the flat plate portion (33), and the tip portion of the tab portion (32) of the current collector (3) on the positive electrode side is provided with a sealing plate (11). The tip of the tab (32) of the current collector (3) on the negative electrode side is welded to the inner surface, and is welded to the bottom surface of the negative electrode can (1).

[0005]

However, FIG.
In the conventional lithium ion secondary battery shown in (1), the current collecting members (3) and (3) are arranged on both sides of the winding electrode body (2), so that not only the number of parts increases but also the weight of the battery increases. There was a growing problem. Accordingly, an object of the present invention is to provide an electric energy storage device capable of reducing the number of parts and reducing the weight.

[0006]

According to the electric energy storage device of the present invention, a sealing plate is fixed to an opening of a metal electrode can having a bottomed cylindrical shape, and an electrode chamber is formed therein. The electrode chamber has a separator (22) between the positive electrode (21) and the negative electrode (23).
An electrode body (2) is installed with the sealing plate interposed therebetween.
An electrode terminal electrically insulated from the battery can is provided. At the bottom of the electrode can, one or a plurality of protrusions (15) projecting toward the electrode chamber are integrally formed, and a positive electrode (21) and a negative electrode (23) are formed.
The end of one of the electrodes is welded to the projection (15) of the electrode can, and the end of the other electrode is connected to the electrode terminal.

In the above electric energy storage device of the present invention, the end of the one electrode is connected to the projection (15) of the battery can.
To make an electrical connection with the battery can. An end of the other electrode is connected to an electrode terminal via a current collector, for example, as in the related art, and is electrically connected to the electrode terminal. Therefore, the electric power generated by the electrode body (2) can be taken out from the electrode can and the electrode terminal.

In the step of welding the end of the one electrode of the electrode body (2) to the projection (15) of the battery can, first, the electrode body (2) is installed inside the battery can, and The end of one electrode is brought into contact with the projection (15). At this time, since the protruding portion (15) protrudes toward the battery chamber, the end of the electrode and the protruding portion (15) are surely in contact with each other. In this state, the projections (15) from the back side of the electrode can
Is irradiated with a laser beam. Thereby, the end of the one electrode and the projection (15) are welded.

More specifically, each of the positive electrode (21) and the negative electrode (23) is formed by coating an active material on the surface of a strip-shaped core, and at least an end of one of the electrodes is coated with the active material. An uncoated portion is formed, and a current collecting portion (5) exposed at an end surface of the electrode body (2) is formed at an edge of the non-coated portion, and the electrode is formed on the current collecting portion (5). The convex part (15) of the can is welded. In the electric energy storage device having the specific configuration, a current collector (5) is formed at the edge of the uncoated portion of the one electrode, and the surface of the current collector (5) is an electrode body. Since it is exposed at the end face of (2), the surface of the current collector (5) and the convex part (15) of the electric can come into contact with each other in a large area,
The electric resistance between the current collector (5) and the protrusion (15) after welding is sufficiently low.

[0010] In a more specific configuration, the edge of the non-coated portion of the one electrode is arranged at one end of the electrode body (2) at intervals, and the current collecting portion (5) is A fusion member is engaged with the edge of the non-coated portion and fused. According to the specific configuration, since the fusion member is fused while being engaged with the non-coated portion of the one electrode, the current collector (5) integrated with the non-coated portion is formed. Is done.

In another specific configuration, the electrode body
At one end of (2), an uncoated portion of the one electrode is folded to form an electrode end surface, and a current collector (5) is formed by depositing a metal thin film on the electrode end surface. is there. According to the specific configuration, by folding the non-coated portion, an electrode end surface formed of the surface of the non-coated portion is formed, and a metal thin film is formed on the electrode end surface. A current collecting part (5) in contact with a large area is formed.

[0012]

In the electric energy storage device according to the present invention, the end of at least one electrode is directly welded to the projection integrally formed on the bottom of the battery can,
Since no current collecting member is conventionally interposed between the electrode and the electrode can, the number of components can be reduced and the weight can be reduced.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention applied to a lithium ion secondary battery will be specifically described below with reference to the drawings. FIG. 1 shows a lithium ion secondary battery according to the present invention.
As shown in the figure, the wound electrode body (2) is accommodated in the bottomed cylindrical negative electrode can (1), and the sealing plate (1) is inserted into the opening of the negative electrode can (1).
1) is fixed, and an insulating member (12) is interposed between the negative electrode can (1) and the sealing plate (11). Further, a positive electrode terminal (13) having a built-in safety valve (14) is attached to the sealing plate (11). At the bottom of the negative electrode can (1), a plurality of protrusions (15) projecting toward the take-up electrode body (2) are integrally formed radially as shown in FIG. In the above lithium ion secondary battery, the electric power generated by the winding electrode body (2) is supplied to the positive electrode terminal.
(13) and the negative electrode can (1) can be taken out.

The winding electrode body (2) is, as shown in FIG.
Strip-shaped positive electrode (21), separator (22) and negative electrode (23) respectively
The positive electrode (21) and the negative electrode (23) are each a separator.
(22) Overlaid on top of each other with a shift in the width direction, and wound in a spiral shape. The positive electrode (21) is formed by applying a positive electrode active material (24) to the surface of a core body made of aluminum foil, and along one edge extending in the longitudinal direction of the electrode, a non-coated positive electrode active material is applied. A coating part (25) is formed. Negative electrode (2
3) is formed by applying a negative electrode active material (26) to the surface of a core body made of copper foil, and along the other edge extending in the longitudinal direction of the electrode, the non-coated non-coated negative electrode active material is applied. A part (27) is formed.

As a result, at one end of both ends in the axial direction of the winding electrode body (2), the edge of the spirally wound positive electrode (21) (the uncoated part (25) ) Is the separator (22)
Projecting beyond the edge of, and at the other end,
Edge of spirally wound negative electrode (23) (uncoated part (27))
Will protrude outward from the edge of the separator (22) (see FIG. 5). For example, the active material coating section of each electrode (24) (2
6) The width A is several tens of mm, and the width B of the uncoated parts (25) and (27) is several m.
m and the projection distance S from the separator (22) can be formed to be about 1 to 3 mm.

A plurality of current collectors (5) are formed radially at both ends of the winding electrode body (2) as shown in FIG. Each of the current collectors (5) is formed by welding a later-described fusing member, and as shown in FIG. 1, the current collector (5) on the positive electrode side.
Is formed integrally with the edge of the positive electrode (21) of the winding electrode body (2), and the current collector (5) on the negative electrode side is connected to the edge of the negative electrode (23) of the winding electrode body (2). It is formed integrally.

A current collecting member (4) made of aluminum is provided on the surface of the current collecting portion (5) on the positive electrode (21) side. The current collecting member (4) includes a flat plate (43) extending along the end surface of the winding electrode body (2), and a tab (42) protruding from the surface of the flat plate (43).
The back surface of the flat plate portion (43) is resistance-welded to the surface of the current collector (5), and the tip of the tab portion (42) is resistance-welded to the back surface of the sealing plate (11). In addition, winding electrode body (2)
Means that each of the current collectors (5) on the negative electrode (23) side is
The tip of the projection (15) is laser-welded to the current collector (5) of the winding electrode body (2).

In the above lithium ion secondary battery,
At both ends of the wound electrode body (2), a current collector (5) integral with the electrode edge is formed, and between the current collector (5) and the current collector (4), as well as the current collector. Part (5) and convex part (15) of negative electrode can (1)
The contact area between them is sufficiently large and the contact resistance is sufficiently reduced, so that high current collection efficiency can be obtained. In addition, negative electrode can (1)
Winding electrode body (2) by convex part (15) integrally molded with
A positive contact between the current collector (5) on the negative electrode side and the negative electrode can (1) is achieved, and a current collecting member is provided between the current collector (5) and the negative electrode can (1). Since there is no interposition, the winding electrode body is
Compared with the configuration in which the current collecting members (4) and (4) are arranged on both sides of (2), the number of components can be reduced and the battery can be reduced in weight.

Next, a method for manufacturing the above lithium ion secondary battery will be described. After the wound electrode body (2) shown in FIG. 2 is manufactured in the same manner as in the prior art, as shown in FIG. 5, the edge of the spiral positive electrode (21) protruding from the end of the wound electrode body (2). That is, a plurality of coil members (6) made of aluminum are radially arranged and engaged with the uncoated portion (25), and an aluminum bar (61) is provided at the center of each coil member (6). Let it penetrate. Similarly, a plurality of copper coil members (6) are radially arranged and engaged with the edge of the spiral negative electrode (23), that is, the uncoated portion (27), and the center of each coil member (6) is engaged. A copper bar (61) is passed through the part.

Thereafter, a laser welding using a YAG laser or the like is performed on the installation portion of each of the coil members (6) and the bar (61), and the coil member (6) and the bar (61) are wound up. body
Weld to the electrode edge of (2). Thereby, the coil member
Substantially the entirety of (6) and the rod (61) are melted and fused to the edge of the electrode as shown in FIG. At this time, the coil member (6) is fused to the electrode edge while being deeply engaged with the electrode edge.
Even if the cores constituting the positive electrode and the negative electrode are thin, welding defects such as the core being broken by melting do not occur. As a result, a plurality of current collectors (5) integrally connected to the respective electrodes are formed radially on each end face of the wound electrode body (2) as shown in FIG.

Incidentally, instead of the coil member (6) and the bar (61), as shown in FIG. 6, a comb-shaped member (7) having a plurality of grooves (71) recessed at a constant pitch may be employed. It is possible, as shown in FIG. 7, to engage the comb-shaped member (7) with the spiral electrode edge protruding from the end of the wound electrode body (2),
Laser welding is performed on the comb-shaped member (7). As a result, the current collector (5) shown in FIG. 1 is formed.

Also, without using the coil member (6) or the like,
As shown in FIG. 8 (a), the non-coated portion (27) on the negative electrode side protruding from the end of the wound electrode body (2) is folded inward, and the electrode end face is formed by the surface of the non-coated portion (27). After the formation of FIG.
As shown in (b), the current collector (5) can be formed by applying a metal thin film made of aluminum or the like in a radial pattern so as to cover the electrode end face. For forming the metal thin film, a known film forming method such as a vacuum evaporation method, a plasma spraying method, and a metallikon method can be employed.

Next, the flat plate portion (4) of the current collecting member (4) is attached to the exposed end face of the current collecting portion (5) on the positive electrode (21) side of the wound electrode body (2).
3) After resistance welding, the wound electrode body (2) is
Install inside (1). At this time, the positioning is performed so that each current collecting portion (5) of the winding electrode body (2) and each convex portion (15) of the negative electrode can (1) come into contact with each other. In this state, as shown in FIG. 9 (a), YA is moved from the back side of the negative electrode can (1) toward the convex portion (15).
A laser beam is emitted using a G laser or the like. As a result, as shown in FIG. 9B, a nugget (16) is formed between the current collecting portion of the winding electrode body (2) and the projection (15) of the negative electrode can (1), and the winding electrode body is formed. Current collecting part of (2) and convex part of negative electrode can (1)
(15) are welded to each other.

Thereafter, the tab portion (4) of the current collector (4) on the positive electrode side is formed.
2) is resistance-welded to the sealing plate (11), and an electrolyte is injected into the negative electrode can (1). Then, the sealing plate (11) is swaged and fixed to the negative electrode can (1). As a result, the lithium ion secondary battery shown in FIG. 1 is completed.

The configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims. For example, the structure for connecting the current collector (5) on the positive electrode side of the winding electrode body (2) to the sealing plate (11) is not limited to the structure using the current collector (4) shown in FIG. It is possible to employ various connection structures.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lithium ion secondary battery according to the present invention.

FIG. 2 is a partially developed perspective view of a wound electrode body.

FIG. 3 is a diagram illustrating a plurality of current collectors formed on an end surface of a wound electrode body.

FIG. 4 is a partially broken perspective view showing a plurality of projections formed on the bottom of the negative electrode can.

FIG. 5 is a partially cutaway front view showing a state in which a coil member and a bar are taken out and engaged with an electrode body in a step of forming a current collector.

FIG. 6 is a perspective view of a comb-shaped member used in another method of forming a current collector.

FIG. 7 is a partially broken front view showing a state in which a comb-shaped member is engaged with a winding electrode body.

FIG. 8 is a perspective view showing still another method for forming a current collector.

FIG. 9 is a cross-sectional view showing a step of laser welding a current collecting portion of the wound electrode body to the bottom of the negative electrode can.

FIG. 10 is a cross-sectional view of a conventional lithium ion secondary battery.

[Explanation of symbols]

 (1) Negative electrode can (11) Sealing plate (12) Insulating member (13) Positive electrode terminal (15) Convex part (2) Winding electrode body (21) Positive electrode (22) Separator (23) Negative electrode (4) Current collecting member (5) Current collector

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01M 2/02 H01M 4/02 B 2/04 10/40 Z 2/06 H01G 9/00 301F 2/30 9/06 Z 4/02 9/08 F 10/40 9/24 D (72) Inventor Takuji Ohno 1-1, Sanyocho, Daito-shi, Osaka Sanyo Electronics Parts Co., Ltd. F-term (reference) 5H011 AA00 AA09 CC06 DD06 DD15 EE04 FF03 GG02 5H014 AA06 BB08 CC01 CC07 EE05 5H022 AA09 BB02 BB03 BB16 BB17 CC02 CC13 CC19 CC24 EE01 EE04 5H029 AJ00 AJ14 AM01 BJ02 BJ14 BJ27 CJ03 CJ05 CJ06 CJ07 DJ12 DJ02 DJ05 DJ02 DJ05

Claims (5)

[Claims] 1. A sealing plate is fixed to an opening of an electrode can having a cylindrical shape with a bottom, and an electrode chamber is formed therein.
An electrode body (2) having a separator (22) interposed between a positive electrode (21) and a negative electrode (23) is provided, and a sealing plate is provided with electrode terminals electrically insulated from a battery can, Positive electrode (21) and negative electrode
(23) Any one of the electrodes is connected to the electrode can, and the other electrode is connected to the electrode terminal. An electric energy storage device, wherein a plurality of protrusions (15) are integrally formed, and the protrusions (15) are welded to ends of the one electrode. 2. The positive electrode (21) and the negative electrode (23) are each formed by coating an active material on the surface of a strip-shaped core, and at least the end of one of the electrodes is not coated with the active material. A non-coated portion is formed, and a current collecting portion (5) exposed at an end face of the electrode body (2) is formed at an edge of the non-coated portion, and the convex portion of the electrode can is formed on the current collecting portion (5). The electrical energy storage device according to claim 1, wherein the part (15) is welded. 3. An end of an uncoated portion of the one electrode is arranged at one end of the electrode body (2) at an interval, and a current collector is provided.
(5) The electric energy storage device according to claim 2, wherein a fusion member that engages with an edge of the uncoated portion is fused. 4. An electrode end face is formed at one end of the electrode body (2) by folding an uncoated portion of the one electrode, and a current collector (5) is provided with a metal thin film on the electrode end face. The electric energy storage device according to claim 2, wherein the electric energy storage device is formed. 5. The projection (15) is laser-welded to an end of the one electrode by irradiating the projection (15) with a laser beam from the back side of the electrode can. An electrical energy storage device according to claim 4.