JP2001256950A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery with internal resistance lower than conventional ones, and further with current-collecting structure superior in productivity. SOLUTION: In the nonaqueous electrolyte secondary battery, unpainted portions where active substance is painted project from core bodies that constitute the positive or negative pole at the end of axial direction of a coiled electrode body 4, and a plurality of collecting terminals 5 are caulked and fixed to the end portions of the said electrode body. The collecting terminal 5 is shaped in a single body with U-shaped cross section, and formed with a plurality of projections on the inner face of one side plate while a plurality of recesses facing the said projections on the inner face of the other side plate. And each collecting terminal 5 is connected to an electrode terminal 91 through leads 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery can, in which a wound electrode body serving as a secondary battery element is housed, and a power generated by the wound electrode body is supplied from a pair of electrode terminals provided on the electrode can. The present invention relates to a non-aqueous electrolyte secondary battery that can be taken out.

[0002]

2. Description of the Related Art In recent years, lithium ion secondary batteries with high energy density have been attracting attention as power sources for portable electronic devices, electric vehicles and the like. For example, a relatively large capacity cylindrical lithium-ion secondary battery used for electric vehicles,
As shown in FIGS. 7 and 8, lids (12) are attached to both ends of the cylindrical body (11).
(12) is welded and fixed inside a cylindrical battery can (1),
It is configured to house the winding electrode body (2). Both lids
(12) On (12), a pair of positive and negative electrode terminal mechanisms (9) and (9) are attached, and both poles of the winding electrode body (2) and both electrode terminal mechanisms (9) and (9) are provided. Each is connected to each other by a plurality of electrode tabs (3), so that the electric power generated by the winding electrode body (2) can be taken out from the pair of electrode terminal mechanisms (9) (9). Further, a pressure opening / closing gas discharge valve (13) is attached to each lid (12).

[0003] As shown in FIG. 9, the winding electrode body (2)
A band-shaped separator (22) is interposed between the band-shaped positive electrode (21) and the band-shaped negative electrode (23), and these are spirally wound. The positive electrode (21) is a positive electrode active material composed of a lithium composite oxide on both sides of a band-shaped core composed of aluminum foil.
The negative electrode (23) is formed by applying a negative electrode active material (25) containing a carbon material to both surfaces of a strip-shaped core made of copper foil. The non-aqueous electrolyte is impregnated in the separator (22). The base ends of the plurality of electrode tabs (3) are joined to the positive electrode (21) and the negative electrode (23) by spot welding or the like, respectively, and the front ends protrude from the wound electrode body (2). The electrode tab (3) joined to the positive electrode (21) is made of aluminum foil, and the electrode tab (3) joined to the negative electrode (23).
(3) is formed from copper foil.

[0004] As shown in FIG. 8, a plurality of electrode tabs (3) having the same polarity are provided with one electrode terminal mechanism (31).
It is connected to (9). In FIG. 8, for convenience,
Only the state in which the tip of some of the electrode tabs is connected to the electrode terminal mechanism (9) is shown, and for the other electrode tabs, the state in which the tip is connected to the electrode terminal mechanism (9) is shown. Omitted.

[0005] The electrode terminal mechanism (9) is provided with a lid (1) of the battery can (1).
An electrode terminal (91) is provided so as to penetrate through (2), and a flange (92) is formed at the base end of the electrode terminal (91). An insulating packing (93) is attached to the through-hole of the lid (12), so that electrical insulation and sealing between the lid (12) and the fastening member (91) are maintained. A washer (94) is fitted to the electrode terminal (91) from the outside of the lid (12), and a first nut (95) and a second nut (96) are screwed into the electrode terminal (91). And the first nut (9
Tighten the flange (92) of the electrode terminal (91) and the washer (9).
By pinching the insulating packing (93) by 4),
It has improved sealing performance. The tips (31) of the plurality of electrode tabs (3) are fixed to the flange (92) of the electrode terminal (91) by spot welding or ultrasonic welding.

In a lithium ion secondary battery, since the length of the positive electrode and the negative electrode increases with the size of the battery, the current collecting structure using the electrode tab as described above has a low current collecting property and an internal resistance. Problems such as variations in the discharge capacity and a decrease in the discharge capacity.

In order to obtain a uniform current collecting property over the entire length of the positive electrode and the negative electrode, a current collecting structure as shown in FIG. 10 has been proposed. In the current collecting structure, the wound electrode body (4)
Similarly, a positive electrode (41) formed by applying a positive electrode active material (44) to the surface of a core (45), and a negative electrode (formed by applying a negative electrode active material (46) to the surface of a core (47)) 43) and a separator (42) impregnated with a non-aqueous electrolyte.The positive electrode (41) and the negative electrode (43) are respectively superposed on the separator (42) so as to be shifted in the width direction, and have a spiral shape. Has been wound up. As a result, at one of the two ends in the winding axis direction of the winding electrode body (4), the end of the core body (45) of the positive electrode (41) is moved outward from the edge of the separator (42). The edge (48) protrudes, and at the other end, the core of the negative electrode (43) extends outward from the edge of the separator (42).
The edge (48) of (47) protrudes. A disk-shaped current collector (32) is resistance-welded to both ends of the wound electrode body (4), and the current collector (32) is connected to the electrode terminal mechanism via a lead member (33). Connected to (9).

However, in the non-aqueous electrolyte secondary battery having the current collecting structure shown in FIG.
Since the areas of the edges (48) and (48) of the cores (45) and (47) constituting the positive electrode (41) and the negative electrode (43) of (4) are small, the edge of the core and the current collector plate (3) are small.
There was a problem in that the contact area during 2) was small, which caused the internal resistance of the battery to increase. Further, in order to obtain a high output, it is necessary to reduce the internal resistance as much as possible. Further, in order to reduce the manufacturing cost, a current collecting structure having excellent productivity is required.

Therefore, as shown in FIG.
A state in which a current collector plate (62) having a plurality of bent portions (64) formed in 3) is used, and the current collector plate (62) is pressed against the core edge (48) of the wound electrode body (4). Therefore, a current collecting structure has been proposed in which the bent portion (64) is resistance-welded to the core body edge (48) (for example, Japanese Patent Application Laid-Open No. H11-311).
No. 1497).

Instead of a disk-shaped current collector, a current collector (65) having a plurality of slits (66) as shown in FIG. 12 is wound around the end of the electrode body (4). With the core edge (48) fitted into the slit (66) of the current collecting member (65), the surface of the current collecting member (65) is irradiated with a laser beam to perform laser welding. A current collecting structure has been proposed (for example,
-261441).

[0011]

However, in a current collecting structure in which a current collecting plate having a bent portion is resistance-welded as shown in FIG. 11, when the thickness of a core is extremely small as in a lithium ion secondary battery. In addition, there is a problem that not only welding is difficult, but also electric resistance in a welded portion is large and current collecting performance is still low.

Further, in the current collecting structure in which a current collecting member having a plurality of slits recessed as shown in FIG. 12 is laser-welded to the edge of the core, not only a current collecting member having a complicated shape is required, but also There is a problem that productivity is inferior because welding work is required for the current collecting member.

An object of the present invention is to provide a non-aqueous electrolyte secondary battery having a current collecting structure which has a lower internal resistance than conventional ones and is excellent in productivity.

[0014]

A non-aqueous electrolyte secondary battery according to the present invention comprises a battery can (1) and a wound electrode body (4) housed inside. The winding electrode body (4) has a separator (42) containing a nonaqueous electrolyte interposed between a strip-shaped positive electrode (41) and a strip-shaped negative electrode (43), and winds them in a spiral shape. Each of the positive electrode (41) and the negative electrode (43) is configured by applying an active material to the surface of a belt-shaped core. Winding electrode body
The electric power generated by (4) can be taken out from the pair of electrode terminals. In the winding electrode body (4),
At least one end in the axial direction, a non-coated portion where the active material is not applied to the core constituting the positive electrode (41) or the negative electrode (43) protrudes, and the protruding portion is a winding electrode body. (4) is divided into a plurality of ring-shaped regions (4a), (4b), and (4c) arranged in the radial direction, and each ring-shaped region is provided with a current collecting terminal (5) at one or a plurality of locations in the circumferential direction. It is bundled in an uncoated core bundle (49). Each current collecting terminal (5) is integrally formed in a U-shaped cross section and includes a pair of side plates (52) and (51) facing each other. One or more convex portions are formed on the inner surface of one side plate (52). Is formed, and on the inner surface of the other side plate (51), one or more concave portions facing the convex portion are formed, and the uncoated core bundle (49) is formed by the both side plates (52) and (51). And each collecting terminal (5)
Are connected to one electrode terminal.

In the configuration of the non-aqueous electrolyte secondary battery of the present invention, each of the current collecting terminals (5) has a simple structure having a U-shaped cross section, and can be easily formed by pressing a metal plate, for example. Can be manufactured. In addition, since each current collecting terminal (5) is attached to each uncoated core bundle (49) of the winding electrode body (4) by caulking, there is no need to perform welding or the like.
The mounting process is simple. The uncoated core bundle (49) is strongly pressed from both sides by the both side plates (52) and (51) of the current collecting terminal (5), and the core surfaces are strongly pressed together, and the uncoated core On one side of the body bundle (49), a depression corresponding to the projection of one side plate (52) is generated, and with the occurrence of the depression, a protrusion (49a) is generated on the other side, and The ridge (49a) is
(51). As a result, the current collecting terminal (5) is firmly connected to the uncoated core bundle (49),
Even if a large tensile force is applied, the uncoated core bundle (49)
There is no risk of deviating from In this way, the current collecting terminal (5) and the uncoated core bundle (49) are pressed against each other with a wide contact area,
The electrical resistance at the contact surface is very small. The recess formed in the other side plate (51) of the current collecting terminal (5) is
It can be formed by forming a through hole in (51) or plastically deforming a part of the side plate (51).

In a specific structure, the winding electrode body
Each of the ring-shaped regions (4a), (4b), and (4c) in (4) is divided so that the length when the regions are developed, that is, the area of the active material coating layer is substantially the same. According to this specific configuration, the current collection is uniformly performed from the winding electrode body (4) by the plurality of current collection terminals (5), so that high current collection performance can be obtained.

In a specific configuration, each uncoated core bundle
The base end of the strip-shaped lead (6) is joined to (49), and the uncoated core bundle (49) and the base end of the lead (6) are pressed against each other by the current collecting terminal (5), The tip of each lead (6) is connected to one electrode terminal. According to this specific configuration, the base end of the lead (6) and the uncoated core bundle (49) are strongly pressed against each other by caulking and fixing the current collecting terminal (5), and the mechanical and electrical connection is made. Therefore, there is no need to perform welding or the like, and the connecting step is simple. Also, since the base end of the lead (6) and the uncoated core bundle (49) are strongly pressed with a large contact area with each other, the electric resistance at the contact surface is extremely small.

More specifically, a lead fixing plate (7) is installed inside the battery can (1), and is attached to an end of the electrode terminal mechanism. The tip of the lead (6) extending from the end is connected to the end by caulking the end of the lead fixing plate (7). According to this specific configuration, the tip of the lead (6) is connected to the lead fixing plate (7).
Since it is caulked and fixed to the end of the connection, there is no need to perform welding or the like, and the connection process is simple.

It is to be noted that the positive electrode side current collecting terminal (5), the lead (6),
And the material of the lead fixing plate (7) is aluminum,
Stainless steel, nickel or the like can be used, and copper, stainless steel, nickel or the like can be used as a material of the current collecting terminal (5), the lead (6) and the lead fixing plate (7) on the negative electrode side. As the positive electrode active material constituting the wound electrode body (4), metal oxides such as LiCoO ₂ and LiNiO
_{2, LiCo 1-X Ni X} O 2, is selected from LiMn ₂ O ₄ and the group consisting of complex compounds, can be used at least one kind of material. As the negative electrode active material, a carbon material such as graphite and coke, a lithium metal, a lithium alloy, a metal oxide material such as Li _X Fe ₂ O ₃ and Li _X WO ₂ and a conductive polymer material such as polyacetylene are used. Can be done. Examples of the electrolyte include LiPF ₆ , LiClO ₄ , Li containing metal ions such as lithium ions.
CF ₃ SO _{3 and the} like. In addition, the organic solvent of the electrolyte includes ethylene carbonate, diethyl carbonate,
Dimethoxymethane, sulfolane, or the like can be used alone or as a mixture. Examples of the electrolyte include a solution in which the electrolyte is dissolved in these solvents at a ratio of about 0.7 to 1.5 M (mol / l).

[0020]

According to the non-aqueous electrolyte secondary battery according to the present invention, a current collecting terminal is provided on the uncoated core bundle (49) of the wound electrode body (4).
Since the work of attaching (5) is simple, higher productivity than before is realized. Further, since the electric resistance between the wound electrode body (4) and the electrode terminal can be reduced, the current collection efficiency is improved and a higher output density than before can be obtained.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment in which the present invention is applied to a cylindrical lithium ion secondary battery will be specifically described with reference to the drawings. As shown in FIGS. 7 and 1, a cylindrical lithium ion secondary battery according to the present invention has a cylindrical battery can formed by welding and fixing lids (12) and (12) to both ends of a cylindrical body (11). The winding electrode body (4) is housed inside (1). Both lids (12) and (12) have a pair of positive and negative electrode terminal mechanisms (9)
(9) is attached, and both poles of the take-up electrode body (4) and the two-electrode terminal mechanisms (9) and (9) are connected to each other by a current collecting structure to be described later. ) Can be taken out of the pair of electrode terminal mechanisms (9) and (9) to the outside. Further, a pressure opening / closing gas discharge valve (13) is attached to each lid (12).

The winding electrode body (4) is, as shown in FIG.
A band-shaped separator (42) is interposed between the band-shaped positive electrode (41) and the band-shaped negative electrode (43), and these are spirally wound. The positive electrode (41) is formed by applying a positive electrode active material (44) made of a lithium composite oxide to both surfaces of a band-shaped core (45) made of aluminum foil, and the negative electrode (43) is made of a band-shaped core made of copper foil. Negative electrode active material (46) containing carbon material on both sides of the body (47)
Is applied. The separator (42) is impregnated with a non-aqueous electrolyte. Further, a non-coated portion of the core body on which the positive electrode active material (44) is not applied is formed at one end of the positive electrode (41), and the negative electrode active material is formed at the other end of the negative electrode (43). (46)
A non-coated portion of the core body is not formed.

In the production of the wound electrode body (4), the positive electrode
The negative electrode (41) and the negative electrode (43) are superposed on the separator (42) so as to be shifted in the width direction, and are spirally wound. As a result, at one of the two ends in the winding axis direction of the winding electrode body (4), the one end of the positive electrode (41) is located outside the edge of the separator (42). The edge (48) protrudes, and at the other end, the edge (48) of the core non-coated portion of the negative electrode (43) protrudes outward from the edge of the separator (42).

A plurality of current collecting terminals (5) are attached to both ends of the wound electrode body (4) on the positive electrode side and the negative electrode side, respectively. As shown in FIGS. 4 and 5, the current collecting terminal 5 is integrally formed in a U-shaped cross section and includes a pair of side plates 52 and 51 facing each other. Four protrusions (54) are formed on the inner surface of one side plate (52), and four through holes (53) are formed on the inner surface of the other side plate (51) so as to face the protrusions. ing. The current collecting terminal (5) for the positive electrode has a thickness of 0.8 mm.
The current collecting terminal (5) for the negative electrode is manufactured by integrally molding a copper plate having a thickness of 0.6 mm. Each of the current collecting terminals (5) has a width D of 6 m.
m, height H is 6 mm, width W is 3 mm, diameter A of the projection (54)
Is 0.8 mm, height B is 0.2 mm, and inner diameter C of the through hole (53).
Is formed to 1 mm.

As shown in FIG. 1, the core non-coated portion projecting from each end of the winding electrode body (4) has three ring-shaped regions (4a) arranged in the radial direction of the winding electrode body (4). ), (4b) and (4c), and two current collecting terminals (5) are caulked and fixed to each ring-shaped region with a phase difference of 180 °. Thus, six uncoated core bundles arranged on the diameter line of the wound electrode body (4)
(49) to (49) are formed. In addition, the winding electrode body (4)
The three ring-shaped regions (4a), (4b), and (4c) are divided so that the length, that is, the area, of the active material coating layer when these regions are developed is substantially the same.

A base end of a strip-shaped lead (6) is connected to each current collecting terminal (5), and six leads (6) having the same polarity are connected.
Are connected to the lower end of the electrode terminal mechanism (9) via a lead fixing plate (7).

FIGS. 6A and 6B show a step of caulking and fixing the current collecting terminal (5) to each uncoated core bundle (49) of the winding electrode body (4). First, as shown in FIG. 7A, between the both side plates (52) and (51) of the current collecting terminal (5), the uncoated core bundle (49) and the strip-shaped lead are provided.
Insert with the ends of (6) overlapped. At this time, the ends of the uncoated core bundle (49) and the lead (6) are connected to both side plates (52) (51).
(52) (51) so that it can be easily inserted between
Is set. Next, as shown in FIG. 6B, appropriate jigs (not shown) are attached to both side plates (52) and (51) of the current collecting terminal (5).
Caulking is performed using. As a result, the uncoated core bundle (49) is strongly pressed from both sides by the both side plates (52) and (51) of the current collecting terminal (5), and the core surfaces are strongly pressed against each other, and uncoated. On one side of the core body bundle (49), a depression corresponding to the projection (54) of one side plate (52) is formed, and with the occurrence of the depression, a protrusion (49a) is formed on the other side. ) Occurs and the ridge
(49a) protrudes into the through hole (53) of the other side plate (51).
As a result, the current collecting terminal (5) is firmly connected to the uncoated core bundle (49), and even if a large tensile force is applied, the current collecting terminal (5) is removed from the uncoated core bundle (49). There is no risk of coming off. In this way, the current collecting terminal (5) and the uncoated core bundle (49) are pressed against each other with a large contact area, and the electric resistance at the contact surface becomes extremely small.

As shown in FIG. 1, the electrode terminal mechanism (9) includes an electrode terminal (9) attached through the lid (12) of the battery can (1).
1), and a flange (90) is formed at the base end of the electrode terminal (91). Insulation packing (93) in through hole of lid (12)
Is attached, and the electrical insulation and sealing between the lid (12) and the fastening member (91) are maintained. The electrode terminal (91) has a lid
A washer (94) is fitted from the outside of (12) and the first
The nut (95) and the second nut (96) are screwed. Then, the first nut (95) is tightened, and the flange of the electrode terminal (91) is tightened.
By pressing the insulating packing (93) with the washer (92) and the washer (94), the sealing property is enhanced.

As shown in FIG. 3, the lead fixing plate (7) is formed by forming a pair of projecting pieces (71) (71) at both ends of a band-shaped main body (70). (91) fits into the groove (97) formed on the back surface of the flange (90), and is formed by ultrasonic welding or the like.
Fixed to (90). The tip of the lead (6) extending from each current collecting terminal (5) is connected to the end of the lead fixing plate (7), and the pair of protruding pieces (71) (71) is caulked to perform the crimping. It is fixed to the end. The lead on the positive electrode side (6)
And the lead fixing plate (7) is made of aluminum, the thickness of the lead (6) is 0.3 mm, the width is 6 mm, and the lead fixing plate is
(7) has a thickness of 1.0 mm and a width of 8 mm. The lead (6) and the lead fixing plate (7) on the negative electrode side are made of copper,
The lead (6) has a thickness of 0.3 mm and a width of 6 mm, and the lead fixing plate (7) has a thickness of 1.0 mm and a width of 8 mm.

In the cylindrical lithium ion secondary battery, the current collecting terminal (5) can be easily manufactured by press-molding a metal plate.
Since it can be attached to each uncoated core bundle (49) by caulking and fixing (4), there is no need to perform welding or the like, and the attaching process is simple. As a result, high productivity is obtained. In addition, the current collecting terminal (5) is fixed by caulking,
Since the lead (5) and the lead (6) are strongly bonded to each other with a large contact area, the electric resistance at the contact surface is extremely small. As a result, the current collection efficiency is improved, and a higher output density than before can be obtained.

[0031]

EXAMPLE A battery A of the example shown in FIG. 1 and a battery B of the comparative example shown in FIG. 8 were produced as follows, and their performances were compared.

[0032]Production of Example Battery A  (Preparation of positive electrode) LiNi as positive electrode active material_0.7Co
_0.3O₂Is the hydroxide of lithium and the hydroxide of nickel
Product and cobalt hydroxide in air at 800 ° C
For 24 hours. This positive electrode active material
And carbon as a conductive agent in a weight ratio of 90: 5
Thus, a positive electrode mixture was obtained. Next, the polyvinyl fluoride binder
Dissolve Nilidene in N-methyl-2-pyrrolidone (NMP)
Then, an NMP solution was prepared. Then, the positive electrode mixture and po
Make sure that the weight ratio of vinylidene fluoride is 95: 5.
The electrode mixture and the NMP solution were kneaded to prepare a slurry.
This slurry was applied to both sides of an aluminum foil as a positive electrode core.
Apply to the surface by the doctor blade method, 2 hours at 150 ° C
A vacuum drying was performed to obtain a positive electrode. In addition, the positive electrode core
Forms an uncoated portion 20 mm wide from the edge of the core
Was.

(Preparation of Negative Electrode) Carbon lump (d002 = 3.356
{Lc> 1000}) and pulverized by injecting an air stream, and sieving to obtain a graphite powder having an average particle diameter of 18 μm. Next, an air stream was injected into the coke mass to pulverize the coke mass, which was then sieved to obtain coke powder having an average particle size of 18 μm. Also, polyvinylidene fluoride as a binder is replaced with N
It was dissolved in MP to prepare an NMP solution. Then, the graphite powder, the coke powder, and the NMP solution were kneaded so that the weight ratio of the graphite powder, the coke powder, and the polyvinylidene fluoride was 72:18:10, to prepare a slurry. This slurry was applied to both surfaces of a copper foil as a negative electrode core by a doctor blade method, and vacuum dried at 150 ° C. for 2 hours to obtain a negative electrode. In addition, the non-coating part whose width from the core body edge was 20 mm was formed in the negative electrode core body.

(Assembly of Battery) Using the positive electrode and the negative electrode obtained by the above steps and a separator made of an ion-permeable polyethylene microporous membrane, a wound electrode body (4) shown in FIG. 2 was prepared. did. Then, as shown in FIG. 1, at the positive electrode side and the negative electrode side end of the winding electrode body (4), respectively,
Fix the 6 current collecting terminals (5) by caulking and fix each uncoated core bundle.
After connecting the base end of the lead (6) to (49), the wound electrode body (4) was housed in the cylinder (11). On the other hand, the electrode terminal mechanism (9) was attached to each lid (12), and the lead fixing plate (7) was fixed to the flange (90) of the electrode terminal (91). Next, the tip of the lead (6) extending from each current collecting terminal (5) of the winding electrode body (4) is connected to the end of the lead fixing plate (7), and then the cylindrical body (1) is connected.
The lid (12) was fixed to each opening of (1) by welding, and
Was assembled.

[0035]Preparation of Comparative Example Battery B  Do not provide uncoated parts in the manufacturing process of the positive and negative electrodes.
Example 2 except that the slurry was entirely applied to the core.
A positive electrode and a negative electrode were produced in the same manner as in Pond A. (Assembly of battery) As shown in FIG.
15 aluminum electrode tabs on the surface of the minium foil
Copper that is welded at intervals of 20 cm and constitutes the negative electrode
Welded 15 copper electrode tabs at 20cm intervals on the surface of foil
did. An ion-permeable polyelectrode is placed between the positive and negative electrodes.
With a separator consisting of a microporous membrane made of
Was spirally wound to produce a wound electrode body (2).
The thickness of the electrode tabs of the positive electrode and the negative electrode was set to 0.1 mm.
Was. Then, as shown in FIG. 8, the electrode tab (3) of each electrode is
Comparative example battery B was welded to the flange portion (92) of the electrode terminal mechanism (9).
Was assembled. In addition, each battery of Example battery A and comparative example battery B
The amount of active material applied on the pole was the same.

(Performance Comparison Experiment) For the battery A of the example and the battery B of the comparative example, before the wound electrode body was housed in the cylindrical body,
When the AC impedance at 1 kHz was measured, the results shown in Table 1 below were obtained. The measurement of the AC impedance was performed between the electrode terminal and the core-uncoated portion located on the outermost periphery of the wound electrode body on both the positive electrode side and the negative electrode side.

[0037]

[Table 1]

As is clear from Table 1, on both the positive electrode side and the negative electrode side, the impedance of the battery A of the example is smaller than the impedance of the battery B of the comparative example.
From this, it can be said that according to the cylindrical lithium ion secondary battery of the present invention, it is possible to obtain a higher output density than the conventional battery.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross-sectional configuration and a planar configuration of a current collecting structure employed in a cylindrical lithium ion secondary battery according to the present invention.

FIG. 2 is a partially developed perspective view of a winding electrode body provided in the secondary battery.

FIG. 3 is a perspective view showing a connection structure between a current collecting terminal and an electrode terminal.

FIG. 4 is an enlarged perspective view of a current collecting terminal.

FIG. 5 is a sectional view of a current collecting terminal.

FIG. 6 is a cross-sectional view illustrating a step of caulking and fixing a current collecting terminal to a lead and a non-coated core bundle.

FIG. 7 is a perspective view showing the appearance of a cylindrical lithium ion secondary battery.

FIG. 8 is a cross-sectional view illustrating a current collecting structure employed in a conventional cylindrical lithium ion secondary battery.

FIG. 9 is a partially developed perspective view of a winding electrode body provided in the secondary battery.

FIG. 10 is a partially developed perspective view of a conventional wound electrode body having another current collecting structure.

FIG. 11 is a perspective view showing still another conventional current collecting structure.

FIG. 12 is a perspective view showing still another conventional current collecting structure.

[Explanation of symbols]

 (1) Battery can (11) Cylindrical body (12) Lid (4) Winding electrode body (49) Uncoated core bundle (5) Current collecting terminal (51) Side plate (52) Side plate (53) Through hole (54) Convex part (6) Lead (7) Lead fixing plate (9) Electrode terminal mechanism

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsuhiro Funabashi 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Toshiyuki Noma 2-chome Keihanhondori, Moriguchi-shi, Osaka 5-5 Sanyo Electric Co., Ltd. (72) Inventor Ikuo Yonezu 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. 5H011 AA03 AA09 EE02 EE04 FF04 GG02 HH02 5H022 AA09 AA18 BB03 CC03 CC04 CC05 CC10 CC12 CC13 CC15 CC20 CC23 CC24 EE03 EE04 5H028 AA01 AA07 AA08 CC05 CC07 CC08 CC12 CC22 CC26 EE01 HH05 5H029 AJ06 AJ14 AK03 AL02 AL03 AL06 AL07 AL12 AM03 DJ04 J05 C07 DJ04 HJ04 HJ12

Claims (4)

[Claims] 1. A separator (4) containing a non-aqueous electrolyte between a strip-shaped positive electrode (41) and a strip-shaped negative electrode (43) inside a battery can (1).
A winding electrode body (4) obtained by spirally winding these with the interposition of 2) is housed, and each of the positive electrode (41) and the negative electrode (43) is formed by applying an active material to the surface of the belt-shaped core. In the non-aqueous electrolyte secondary battery capable of taking out the electric power generated by the winding electrode body (4) from the pair of electrode terminals to the outside, at least one end in the axial direction of the winding electrode body (4) In the part, the non-coated part where the active material is not applied to the core constituting the positive electrode (41) or the negative electrode (43) protrudes, and the protruding part is
The ring-shaped region is divided into a plurality of ring-shaped regions (4a), (4b), and (4c) arranged coaxially with the center axis of the winding electrode body (4). The current collecting terminals (5) are bundled into an uncoated core bundle (49), and each of the current collecting terminals (5) is integrally molded in a U-shaped cross section, and a pair of side plates facing each other are formed.
(52) (51), wherein one or a plurality of convex portions are formed on the inner surface of one side plate (52), and the inner surface of the other side plate (51) has one Alternatively, a plurality of concave portions are formed, and the uncoated core bundle (49) is sandwiched between both side plates (52) and (51), and each current collecting terminal (5) is connected to one electrode terminal portion. Non-aqueous electrolyte secondary battery characterized by the above-mentioned. 2. Each of the ring-shaped regions (4a), (4b), and (4c) of the winding electrode body (4) is divided so that the lengths of these regions when expanded are substantially the same. The non-aqueous electrolyte secondary battery according to claim 1. 3. Each of the uncoated core bundles (49) has a strip-shaped lead (6).
The uncoated core bundle (49) and the proximal end of the lead (6) are crimped together by the current collecting terminal (5), and the distal end of each lead (6) is connected to one end. The non-aqueous electrolyte secondary battery according to claim 1, wherein the non-aqueous electrolyte secondary battery is connected to the electrode terminal portion. 4. A lead fixing plate (7) inside a battery can (1).
Is installed and attached to the end of the electrode terminal mechanism, and the tips of the leads (6) extending from the plurality of current collecting terminals (5) caulk the ends of the lead fixing plate (7). The non-aqueous electrolyte secondary battery according to claim 3, wherein the non-aqueous electrolyte secondary battery is connected to the end portion by a non-aqueous electrolyte.