JP2002170543A - Nonaqueous electrolytic-solution secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolytic-solution secondary battery which is lower in internal resistance than a conventional battery, in the nonaqueous electrolytic-solution secondary battery having a current collecting structure using a collector plate. SOLUTION: In the non-aqueous electrolytic-solution secondary battery of this invention, a takeup electrode 4 is housed within a battery can 1, the collector plate 3 is connected to an end of the electrode 4, a male screw 23 is projectively provided on a face of the collector plate 3 toward an electrode terminal mechanism 2, and the male screw 23 is engaged with a female screw 21a formed at the electrode terminal mechanism 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte secondary battery capable of extracting electric power generated by an electrode body housed in a battery can through a current collector plate.

[0002]

2. Description of the Related Art Conventionally, this type of non-aqueous electrolyte secondary battery has
For example, as shown in FIG. 9, a battery can (1) comprising a lid (12) (12) provided with an electrode terminal mechanism (9) (9) and a gas discharge valve (13) (13) and a cylinder (11). Inside the winding electrode body shown in FIG.
(4) is accommodated.

As shown in FIG. 10, a winding electrode body (4) comprises a strip-shaped positive electrode (43), a separator (42) and a negative electrode.
The positive electrode (43) and the negative electrode (41) are superposed on the separator (42) while being shifted in the width direction, and are wound in a spiral shape. As a result, at one end of the two ends in the winding axis direction of the winding electrode body (4), the edge (48) of the positive electrode (43) projects outward from the edge of the separator (42). And at the other end a separator
The edge (48) of the negative electrode (41) protrudes outward from the edge of (42). Current collector plates (8) (8) at both ends of the wound electrode body (4)
Are installed and joined to the edges (48) and (48) of the positive electrode (43) and the negative electrode (41).

The current collectors (8) and (8) joined to the edges (48) and (48) of the positive electrode (43) and the negative electrode (41) are respectively connected to the positive electrode (43) of the wound electrode body (4). Alternatively, the current collector plate (8) is pressed and welded to the edge (48) of the negative electrode (41), and a lead portion (85) protrudes from the outer periphery of each current collector plate (8).

[0005] As shown in FIG.
It is folded toward the inside of the current collector plate (8), and its tip is joined to the flange (92) of the electrode terminal (91) of the electrode terminal mechanism (9). The two electrode terminal mechanisms (9) and (9) are respectively battery cans (1)
An electrode terminal (91) consisting of a screw member attached through the lid (12) of
(92) is formed. An insulating member (93) made of resin is mounted in the through hole of the lid (12), and electrical insulation and sealing between the lid (12) and the electrode terminal (91) are maintained. Electrode terminal
(91) is fitted with a washer (94) from the outside of the battery can (1), and a first nut (95) and a second nut (96) are screwed together. Then, the first nut (95) is tightened, and the flange (92) of the electrode terminal (91) and the washer (94) are used to insulate the insulating member (9).
By narrowing the pressure of 3), the sealing performance is improved. or,
The second nut (96) is used for connection to an external circuit. With the above configuration, the electric power generated by the winding electrode body (4) can be taken out from the pair of positive and negative electrode terminal mechanisms (9) (9).

[0006] With the spread of electric vehicles in recent years, there has been a demand for improved output of non-aqueous electrolyte secondary batteries as power sources. Therefore, a non-aqueous electrolyte secondary battery including a current collector plate (7) having the shape shown in FIG.
No. 4102). A center hole (74) is formed in the current collector (7), and a lead portion (75) protrudes from an outer peripheral edge thereof. Further, the current collector plate (7) has a cross section V extending radially from the center.
A plurality of U-shaped convex portions (72) are provided, as shown in FIG.
These projections (72) are connected to the edge (4) of the electrode of the wound electrode body (4).
8) It is pressed and welded. In the non-aqueous electrolyte secondary battery, since the convex portion (72) of the current collector plate (7) cuts into the edge (48) of the electrode of the wound electrode body (4), the conventional flat plate collector is used. Compared with the power plate (8), the contact area between the current collector (7) and the edge (48) of the electrode is increased, thereby increasing the amount of current collected and increasing the output of the battery.

To improve the output of this type of non-aqueous electrolyte secondary battery, it is also effective to reduce the internal resistance. The internal resistance is an electric resistance in a current path until power generated by the winding electrode body (4) is taken out to the outside. As shown in FIG. 11, the path includes a current collector plate (8) and a lead portion. (85) and an electrode terminal (91).

[0008]

However, in the current collector plate (7) shown in FIG. 12, the lead portion (75) is protruded from the outer peripheral edge of the current collector plate (7). The average distance until the current collected in (7) flows into the lead portion (75) is long.
Further, since the lead portion (75) protrudes from the outer peripheral edge of the current collector (7), the distance from the current to the electrode terminal via the lead portion (75) is long. As a result, in the non-aqueous electrolyte secondary battery using the current collector plate (7), the internal resistance was still large.

It is an object of the present invention to provide a non-aqueous electrolyte secondary battery having a current collection structure using a current collector plate and having a smaller internal resistance than conventional ones.

[0010]

Means for Solving the Problems In the nonaqueous electrolyte secondary battery of the present invention, these are laminated inside a battery can with a separator containing a nonaqueous electrolyte interposed between a pair of positive and negative electrodes. The electrode body is housed, and the power generated by the electrode body can be taken out from a pair of electrode terminals provided at both ends of the battery can. At least one end of the electrode body protrudes an edge of a core body constituting an electrode, a current collector is joined to the edge, and an electrode terminal portion is formed on the surface of the current collector. The male screw is screwed to be formed on the electrode terminal portion. In the non-aqueous electrolyte secondary battery of the present invention, since the male screw projecting from the surface of the current collector plate is directly screwed into the electrode terminal portion, the shortest distance between the current collector plate and the electrode terminal portion is minimized. A current path is formed. Therefore,
The internal resistance of the non-aqueous electrolyte secondary battery decreases.

In a specific configuration of the present invention, the male screw is formed integrally with the current collector. According to this specific configuration, since there is no joint between the current collector plate and the male screw and there is no contact resistance, the internal resistance of the non-aqueous electrolyte secondary battery is small.

In another specific configuration, a base plate is joined to a central portion of the surface of the current collector plate, and the male screw protrudes from the surface of the base plate. According to the specific configuration, the base plate provided with the male screw is separate from the current collector plate,
It can be manufactured using a low-resistance material different from the material of the current collector plate. Furthermore, the male screw is located at the center of the current collector, and the average distance until the current collected by the current collector reaches the male screw is short. Therefore, the internal resistance of the non-aqueous electrolyte secondary battery decreases.

In still another specific configuration, edges of a core constituting the electrode protrude from both ends of the electrode body, and current collector plates are joined to the both edges, respectively. On one current collector plate, a male screw is protruded, and on the other current collector plate, a connecting member having elasticity is protruded in a direction approaching and separating from the electrode terminal, and a distal end portion of the connecting member is provided. It is joined to the electrode terminal. According to this specific configuration, at the end of one electrode body, an elastic connecting member is interposed between the electrode terminal portion and the current collector plate. Assembly errors can be absorbed. Therefore,
Strict dimensional control is not required, and the production efficiency of the non-aqueous electrolyte secondary battery is improved.

[0014]

According to the present invention, it is possible to provide a non-aqueous electrolyte secondary battery having a smaller internal resistance than conventional ones.

[0015]

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.

[0016]First embodiment  The lithium ion secondary battery of the present embodiment is as shown in FIG.
The lids (12) and (12) are fixed to both ends of the cylindrical body (11) by welding.
The wound electrode body (4) is housed inside the battery can (1)
It is configured. Both lids (12) and (12) have a pair of positive and negative electrodes
Terminal mechanism (9) (2) and gas discharge valve (13) (13) are attached
ing.

The wound electrode body (4) has the same structure as the conventional structure shown in FIG. 10, and is composed of a strip-shaped positive electrode (43), a separator (42) and a negative electrode (41). 43)
The negative electrode (41) and the negative electrode (41) are superposed on the separator (42) while being shifted in the width direction, and are wound in a spiral shape.
As a result, at one end of the two ends in the winding axis direction of the winding electrode body (4), the edge (48) of the positive electrode (43) projects outward from the edge of the separator (42). At the same time, at the other end, the edge (48) of the negative electrode (41) protrudes outward from the edge of the separator (42).

As shown in FIG. 1, a pair of positive and negative current collector plates 5 and 3 are provided at both ends of the wound electrode body 4.
(43) and the edges (48) and (48) of the negative electrode (41).

As shown in FIGS. 2 and 3, the current collector plate 3 on the negative electrode side has a central hole (34) and a plurality of liquid injection holes (33). A plurality of convex portions (32) having an arc-shaped cross section extending in the direction shown in FIG.
As shown in the figure, the wound electrode body (4) is pressed against and welded to the edge (48) of the negative electrode. A connecting screw (20) is fixed to the center of the surface of the current collector (3) as shown in FIG. The connecting screw (20) is a cross plate (24) serving as a base plate,
A disc-shaped pedestal (25) protruding from the center of the cross board (24),
And a male screw (23) erected at the center of the pedestal (25).

As shown in FIG. 7, a strip-shaped lead portion (55) protrudes from the outer peripheral edge of the current collector plate (5) on the positive electrode side. The current collector plate (5) has a central hole (54) and a plurality of liquid injection holes (53), and further has a plurality of arc-shaped convex portions (52) extending radially from the center. As shown in FIG. 8, these projections (52) are pressed and welded to the edge (48) of the positive electrode of the wound electrode body (4).

As shown in FIG. 1, the negative electrode terminal mechanism (2) includes an electrode terminal (21) composed of a screw member attached through the lid (12) of the battery can (1). A flange (21b) is formed at the base end of the electrode terminal (21). Electrode terminal (21)
Is formed with a female screw (21a) from the flange portion (21b) toward the screw portion, and the male screw (23) is screwed into the female screw (21a). A metal ring (22) is fitted to the pedestal (25). As shown in FIG. 4, the metal ring (22) is formed to have substantially the same outer diameter as the flange (21b) of the electrode terminal (21), and has a through hole (22a) having a diameter slightly larger than that of the base (25). )have. The metal ring (22) is pressed into contact with the flange portion (21b) and the cruciform plate (24) by the male screw (23) being screwed into the female screw (21a), and is in close contact therewith.

The positive electrode terminal mechanism (9) includes an electrode terminal (91) made of a screw member attached through the cover (12) of the battery can (1). The base end has a collar (9
2) is formed. The lead portion (55) connected to the current collector plate (5) on the positive electrode side is folded back toward the inside of the current collector plate (5), and its tip end is a flange (92) of the electrode terminal (91). And are joined. The lead portion (55) is curved in a bow shape, and can be elastically deformed in a direction approaching and separating from the electrode terminal mechanism (9).

Resin insulating members (26) and (93) are attached to the through holes of the positive and negative electrode lids (12) and (12), respectively, and the lids (12) and (12) and the electrode terminals (21) Electrical insulation and sealing between (91) are maintained. Washers (27) and (94) are fitted to the electrode terminals (21) and (91) from the outside of the battery can (1), and the first nut
(28) (95) and the second nuts (29) (96) are screwed together. Then, the first nuts (28) and (95) are tightened and each electrode terminal (21) is tightened.
Narrow pressure of the insulating members (26) and (93) by the flanges (21b) and (92) of the (91) and the washers (27) and (94) enhances the sealing performance. The second nuts (29) and (96) are used for connection to an external circuit. Thereby, the electric power generated by the winding electrode body (4) can be taken out from the pair of positive and negative electrode terminal mechanisms (9) and (2).

In the non-aqueous electrolyte secondary battery of this embodiment, as shown in FIG. 2, the male screw (23) is connected to the current collector plate (3) on the negative electrode side.
Is located at the center of the current collecting plate (3), the average distance until the current collected by the current collecting plate (3) reaches the male screw (23) is short. or,
As shown in FIG. 1, the male screw (23) is screwed and connected to the female screw (21a) of the electrode terminal (21).
The passage of the current from (3) to the electrode terminal (21) is the shortest distance. Further, as shown in FIG. 1, the cross plate (24), the metal ring (22) and the flange (21b) are in close contact with each other to form a current path having a large cross-sectional area, so that the electric resistance of the current path is small. Becomes This reduces the internal resistance of the battery.

Further, as shown in FIG. 1, the current collector plate on the positive electrode side
The lead portion (55) of (5) is elastically deformed, so that the assembly error of the wound electrode body (4) and the battery can (1) can be absorbed.

Next, a method for manufacturing the above-mentioned lithium ion secondary battery will be described. First, FIG.
A negative electrode side current collector plate (3) shown in FIG. 7 is produced, and a positive electrode side current collector plate (5) shown in FIG. 7 is produced using an aluminum plate. A lead portion (55) is integrally formed on the current collector plate (5) on the positive electrode side. Each of the current collectors (3) and (5) has a radius of 20 mm, a thickness of 1.0 mm, and a convex portion having a depth of 1.4 mm. Connecting screw (2
0) is made of nickel and manufactured in the shape shown in FIG. 2 and FIG. 3, and the thickness of the cruciform plate (24) is 1 mm and the thickness of the pedestal (25) is 1
mm, the outer diameter of the male screw (23) is 6 mm, and the length of the male screw (23) is 9 mm.

Next, a core body made of a strip-shaped aluminum foil
On the surface of (47), a positive electrode active material (4
6) is applied to produce a positive electrode (43), and a negative electrode active material (44) containing a carbon material is applied to the surface of a core (45) made of copper foil to produce a negative electrode (41). Then, the positive electrode (43) and the negative electrode (41)
The separator (42) is sandwiched between the positive electrode (43) and the negative electrode (4
1) is shifted in the width direction and overlapped, and these are spirally wound to produce a wound electrode body (4) as shown in FIG.

Subsequently, as shown in FIG.
The current collector plate (5) is pressed against the edge (48) on the positive electrode side of (4), and the edge (48) and the convex portion (52) of the current collector plate (5) are laser-welded. Tip of (55) and flange of positive electrode side electrode terminal (91)
(92) and laser welding. Similarly, the wound electrode body
The current collector (3) is pressed against the edge (48) on the negative electrode side of (4), and the edge (48) and the projection (32) of the current collector (3) are laser-welded. As shown in FIGS. 2 and 3, a cross plate (24) of a connecting screw (20) is laser-welded to the center of the current collector (3). And
As shown in FIG. 1, the metal ring (22) is fitted to the pedestal (25),
Screw the male screw (23) into the female screw (21a).

Thereafter, the winding electrode body (4) is connected to the cylindrical body (1).
1), a pair of positive and negative electrode terminals (21) and (91) are inserted into the lids (12) and (12) with the insulating members (26) and (93) interposed therebetween, and each of the electrode terminals (21) Fit washer (27) (94) to (91),
Further, the first nuts (28) (95) and the second nuts (29) (96) are screwed together. This allows a pair of positive and negative electrode terminal mechanisms (2)
(9) is assembled to both lids (12) and (12).

Finally, the lids (12) and (12) and the cylinder (11) are welded and fixed, and the battery can is inserted through the mounting hole of one of the gas discharge valves (13).
After injecting the electrolytic solution into (1), the gas exhaust valve (13) is screwed into the mounting hole and sealed. Thus, the lithium ion secondary battery of this embodiment is completed.

[0031]Second embodiment  In the lithium ion secondary battery of the present embodiment, the connecting screw
Is manufactured using copper, and other than this is the same as the first embodiment.
Equipped with the same configuration, as in the first embodiment,
Assemble the lithium ion secondary battery.

[0032]Third embodiment  In the lithium ion secondary battery of this embodiment, FIGS.
As shown in FIG. 6, the current collector plate (6) and the male screw (65) are integrally formed.
This is different from the first embodiment. Negative electrode side
At the center of the surface of the current collector plate (6), a disc-shaped pedestal (66) is provided.
While being formed, a male screw (65) is provided at the center of the base (66).
It is erected. The pedestal (66) has a metal ring shown in FIG.
(67) is fitted. The metal ring (67) is mounted on the pedestal (66).
It has a through hole (68) with a slightly larger diameter than
As a result, the metal ring (67) and the current collector (6) are tightly connected to each other.
To wear. The lithium ion secondary battery of this embodiment has the above-described structure.
Except for the configuration, the second embodiment has the same configuration as the first embodiment, and has the same configuration as the first embodiment.
And assemble. Lithium ion of this embodiment
For secondary batteries, between the current collector plate (6) and the male screw (65)
Since there are no joints and no contact resistance, the internal resistance of the battery
Will be smaller.

Hereinafter, the inventive battery 1 of the first embodiment and the inventive battery 2 of the second embodiment, and the following comparative batteries 1 and 2 were prepared, and the internal resistance of each battery was measured.
The rated power capacity of each battery is about 50 Wh.

[0034]Comparative Example Battery 1  This comparative example battery 1 has a nickel current collector shown in FIG. 7 on the negative electrode side.
It has the same configuration as the first embodiment except that a plate is used.
A battery was assembled in the same manner as in Example 1.Comparative Example Battery 2  In the battery 2 of the comparative example, the convex portions of the positive and negative electrode current collector plates had a V-shaped cross section.
The same configuration as Comparative Example Battery 1 except that it is formed in the shape of
The battery is assembled in the same manner as in the first embodiment.
became.

[Measurement of Internal Resistance] The internal resistance of each battery was measured using a resistance meter (AC 4 terminals, 1 kHz).

[Measurement Results] The measurement results of the internal resistance of each battery are shown in Table 1.

[0037]

[Table 1]

As is clear from the results shown in Table 1, both the inventive battery 1 and the inventive battery 2 have lower internal resistance than the comparative battery 1 and the comparative battery 2. The reason for this is that, in Invention Battery 1 and Invention Battery 2, the male screw is located at the center of the current collector on the negative electrode side, and the average distance until the current collected by the current collector reaches the male screw is reduced. Because it is short. Further, the male screw is screwed into the female screw of the electrode terminal, and the current passage path from the current collector plate to the electrode terminal is the shortest distance. Furthermore, since the metal ring having substantially the same outer diameter as the flange of the electrode terminal is in close contact with the flange and the cross plate, the cross-sectional area of the current path increases.

The battery 2 of the invention has a particularly low internal resistance. The reason for this is that, in the battery 2 of the invention, the connecting screw is formed of copper, and the resistance of copper is smaller than that of nickel, which is the material of the connecting screw of the battery 1 of the invention.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a nonaqueous electrolyte secondary battery of the present invention.

FIG. 2 is a perspective view of a current collector on the negative electrode side used in the battery.

FIG. 3 is a plan view of the current collector plate.

FIG. 4 is an exploded cross-sectional view illustrating a connection structure between an electrode terminal mechanism and a current collector.

FIG. 5 is a perspective view of a current collector plate according to another embodiment.

FIG. 6 is a plan view of the current collector.

FIG. 7 is a plan view of a current collector plate on the positive electrode side.

FIG. 8 is a diagram illustrating a joining process of a convex portion of a current collecting plate and an edge of an electrode of a wound electrode body.

FIG. 9 is a perspective view showing the appearance of a conventional non-aqueous electrolyte secondary battery.

FIG. 10 is a partially developed perspective view of a conventional wound electrode body.

FIG. 11 is a partially broken front view showing a main part of a conventional nonaqueous electrolyte secondary battery.

FIG. 12 is a plan view of a conventional current collector plate.

FIG. 13 is a diagram illustrating a conventional process of joining a convex portion of a current collector plate and an edge of an electrode of a wound electrode body.

[Explanation of symbols]

 (1) Battery can (11) Cylindrical body (12) Lid (2) Electrode terminal mechanism (20) Connecting screw (21) Electrode terminal (23) Male screw (21a) Female screw (22) Metal ring (3) Collection Electroplate (4) Winding electrode body (5) Current collector (6) Current collector (65) Male screw (9) Electrode terminal mechanism

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiyuki Noma 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Ikuo Yonezu 2-chome Keihanhondori, Moriguchi-shi, Osaka No.5-5 Sanyo Electric Co., Ltd. F term (reference) 5H022 AA09 CC03 CC12 CC13 5H029 AJ06 AK03 AL06 DJ02 DJ05 EJ01

Claims (4)

[Claims] An electrode body in which a separator containing a non-aqueous electrolyte is interposed between a pair of positive and negative electrodes is housed inside a battery can, and the power generated by the electrode body is stored in the battery can. In a secondary battery that can be taken out from a pair of electrode terminals provided at both ends, an edge of a core constituting an electrode protrudes from at least one end of the electrode, A current collector plate is joined, and a screw is provided on the surface of the current collector plate toward the electrode terminal portion.
A non-aqueous electrolyte secondary battery, wherein the non-aqueous electrolyte secondary battery is screwed with a screw to be formed on an electrode terminal portion. 2. The non-aqueous electrolyte secondary battery according to claim 1, wherein the male screw is formed integrally with a current collector. 3. The non-aqueous electrolyte secondary battery according to claim 1, wherein a base plate is joined to a central portion of the surface of the current collector plate, and the male screw is provided on the surface of the base plate. 4. An edge of a core constituting the electrode protrudes from both ends of the electrode body, and current collector plates are joined to both ends, respectively.
The male screw protrudes from one of the current collecting plates, and a connecting member having elasticity protrudes from the other current collecting plate in a direction approaching or moving away from the electrode terminal portion. The non-aqueous electrolyte secondary battery according to claim 1, wherein the non-aqueous electrolyte secondary battery is joined to the electrode terminal portion.