JP2001052755A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely fix a rolled electrode body even if vibration or shock is applied from the outside and thereby prevent collapse in winding and positional deviation from occurring by winding a resin sheet expanding by absorption of a nonaqueous electrolytic solution in the wound electrode body, received in a battery can along with a positive and negative electrodes and a separator. SOLUTION: A positive electrode 21 is composed by applying a positive electrode active material 27 to both surfaces of Al foil 26 used as a core body, and plural positive electrode leads 3A are jointed to one of the surfaces of the positive electrode 21. For a negative electrode 23, a negative electrode active material 29 is applied to both surfaces of a core body composed by overlapping two sheets of copper foil 28. An acrylic resin sheet 200 is interlaid between the two sheets of copper foil 28 constituting the negative electrode, and base end parts of plural negative electrode leads 3B are interlaid between both the surfaces of the resin sheet 200 and the inside surfaces of the two sheets of copper foil 28. Preferably, the resin sheet is formed in the thickness range of 5 μm to 50 μm with a nonaqueous electrolytic solution not absorbed, and the circumference of a wound electrode body comes into press contact with the inside peripheral surface of a battery can by absorbing the nonaqueous electrolytic solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical lithium ion secondary battery in which a wound electrode body serving as a power generating element is housed in a closed container, and the electric power generated by the wound electrode body is supplied to a positive electrode terminal. TECHNICAL FIELD The present invention relates to a non-aqueous electrolyte secondary battery that can be taken out of a battery unit and a negative electrode terminal unit, and more particularly to a non-aqueous electrolyte secondary battery with improved durability against externally applied vibration and impact.

[0002]

2. Description of the Related Art In recent years, attention has been paid to a secondary battery which exhibits a high output and a high energy density and can be used stably for a long period of time as a power source for various devices. In particular,
As air pollution by exhaust gas from automobiles and the like has become a global problem, the development of electric vehicles equipped with a non-aqueous electrolyte secondary battery, which is a clean energy source, is in progress.

In a large-capacity cylindrical non-aqueous electrolyte secondary battery used as a power source for an electric vehicle or the like, for example, as shown in FIG. 9, a separator is provided between a positive electrode and a negative electrode inside a battery can (9). The wound electrode body (92) wound in a spiral shape is accommodated therein, and the electrolyte is injected therein.The wound electrode body (92) is connected to the electrode terminal via the pole (94). It is electrically connected to the mechanism (91) (Japanese Patent Laid-Open No. 10-125347).
issue). In the non-aqueous electrolyte secondary battery shown in FIG.
A winding core (93) penetrates through the center of the winding electrode body (92), and a spacer (95) made of an elastic material is interposed between the winding electrode body (92) and the pole (94). Thus, the movement of the winding electrode body (92) due to the action of vibration or impact is prevented.

[0004]

However, in a conventional non-aqueous electrolyte secondary battery as shown in FIG. 9, when used as a power source for an electric vehicle or the like, a repetitive vibration is applied to the wound electrode assembly. (92), and the winding electrode body (92) may be displaced with respect to the winding core (93), whereby the winding electrode body (92) and the electrode terminal mechanism may be displaced. There was a problem that the electrical connection between (91) was disconnected.

Therefore, an object of the present invention is to provide a non-aqueous electrolysis system in which even when vibration or impact is applied from the outside, the winding electrode body is securely fixed in the battery can and there is no possibility of collapse or displacement. It is to provide a liquid secondary battery.

[0006]

Means for Solving the Problems In the nonaqueous electrolyte secondary battery according to the present invention, the wound electrode body (2) housed in the battery can (1) is provided with the absorption of the nonaqueous electrolyte. The expanding resin sheet (200) is wound up together with the positive electrode (21), the negative electrode (23) and the separator (22).

In the above non-aqueous electrolyte secondary battery of the present invention, in the manufacturing process, the wound electrode body (2) is
The resin sheet (200) in the wound electrode body (2) absorbs the electrolyte and expands by containing the battery in the battery can (1) and injecting the electrolyte into the battery can (1). As a result, the winding state of the positive electrode (21), the separator (22), and the negative electrode (23) constituting the winding electrode body (2) becomes tight, and the winding hardness increases. Therefore, even if vibrations or shocks are applied from the outside, there is no fear that the winding electrode body (2) may be broken.

The resin sheet (200) can be formed of a resin material mainly composed of an acrylic resin, or a resin material mainly composed of vinyl chloride, a vinyl chloride / vinyl acetate copolymer or a vinyl butyral resin. These resin materials expand by absorbing the non-aqueous electrolyte.

Further, the thickness of the resin sheet (200) can be formed in a range of 5 μm or more and 50 μm or less without absorbing the non-aqueous electrolyte. This allows the resin sheet (2
(00), a moderate amount of expansion occurs, and the wound electrode body
The winding hardness of (2) is moderate. That is, when the thickness of the resin sheet (200) is less than 5 μm, the winding hardness is insufficient, and when the thickness of the resin sheet (200) exceeds 50 μm, the winding hardness becomes excessive and wrinkles are formed on the electrodes. appear.

In a specific configuration, the winding electrode body (2)
Each of the positive electrode (21) and the negative electrode (23) is formed by forming an active material layer on the surface of a strip-shaped core. Also, the positive electrode (21) and the negative electrode
In (23), the core of at least one electrode is formed by stacking two metal foils, and a resin sheet (200) is interposed between the two metal foils. In the specific configuration, the resin sheet (2
Since (00) absorbs the non-aqueous electrolyte, the distance between the two metal foils is expanded and the thickness of the electrode including the resin sheet (200) is increased. As a result, the wound electrode body
The winding hardness of (2) increases.

More specifically, a strip-shaped lead is interposed between the resin sheet (200) and the metal foil, and the tip of the lead is connected to a positive electrode terminal or a negative electrode terminal. In this specific configuration, the two metal foils are electrically connected to each other by a lead to form an electrically integrated core, and an active material layer is formed on a surface of the core. Therefore, the function is exhibited as one electrode.

In a specific configuration, the wound electrode body
In (2), the resin sheet (200) expands by absorbing the non-aqueous electrolyte, and its outer peripheral surface is pressed against the inner peripheral surface of the closed container. As a result, the wound electrode body (2) is pressed against the inner peripheral surface of the battery can (1), and is strongly fixed inside the battery can (1). Therefore, even if vibration or impact is applied, there is no fear that the wound electrode body (2) moves inside the battery can (1).

Further, according to the configuration in which the winding core (20) is densely penetrated at the center of the winding electrode body (2), the deformation toward the center of the winding electrode body (2) is limited. 20), the wound electrode body (2) expands outward,
A large pressing force can be generated between the outer peripheral surface of the winding electrode body (2) and the inner peripheral surface of the battery can (1). Also, since the winding electrode body (2) is strongly pressed against the outer peripheral surface of the winding core (20), the fixing strength to the winding core (20) increases, so that even if vibration or impact is applied from the outside, winding is performed. Electrode body
There is no possibility that the position (2) is displaced with respect to the winding core (20).

[0014]

According to the non-aqueous electrolyte secondary battery according to the present invention, even when vibration or impact is applied from the outside, the winding electrode body is securely fixed in the battery can, and the winding electrode body is broken or distorted. There is no danger of displacement. As a result, stable use over a long period of time becomes possible.

[0015]

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 FIG. 1, the secondary battery according to the present invention includes a cylindrical battery can (1) formed by welding and fixing lids (12) and (12) to both ends of a cylindrical body (11). As shown in FIG. 2, a wound electrode body (2) is accommodated in the battery can (1), and a non-aqueous electrolyte is injected into the battery can. Also, both lids (12) (1
2) has a pair of positive and negative electrode terminal mechanisms (4) and (4) and a gas discharge valve.
(13) (13) is attached.

The winding electrode body (2) is, as shown in FIG.
A separator (22) is interposed between a positive electrode (21) containing a lithium composite oxide and a negative electrode (23) containing a carbon material, and these are wound around a core.
(20) is formed by spirally winding the outer peripheral surface. The winding core (20) is made of an insulating material such as polypropylene, polyethylene, or ceramics, and has circular concave portions (25) formed on both end surfaces in the longitudinal direction.

The winding electrode body (2) has a plurality of positive electrode leads (3A) extending in the winding axis direction in contact with the positive electrode (21).
And a plurality of negative electrode leads (3B) extending in the direction of the winding axis in contact with the negative electrode (23), and the tips of these leads project from the winding electrode body (2).

As shown in FIG. 4, the positive electrode (21) is formed by applying positive electrode active materials (27) and (27) on both surfaces of an aluminum foil (26) serving as a core. A plurality of positive electrode leads (3A) are joined to one side of the. On the other hand, the negative electrode (23)
The copper foils (28) and (28) are stacked to form a core, and negative electrode active materials (29) and (29) are applied to both surfaces of the core. Negative electrode (2
An acrylic resin sheet (200) is interposed between the two copper foils (28) and (28) constituting 3), and the resin sheet (200)
The base ends of a plurality of negative electrode leads (3B) are interposed between both surfaces of the copper foils (28) and (28), respectively.

Here, the base end of the negative electrode lead (3B) is split in the longitudinal direction as shown in FIG.
(33) and (33) are formed, and the resin sheet (200) is sandwiched between the central lead piece (32) and the lead pieces (33) and (33) on both sides. As a result, as shown in FIG.
(32) is interposed between the resin sheet (200) and one copper foil (28), and the lead pieces (33) (33) on both sides are the resin sheet (200).
And the other copper foil (28).
8) Mutual electrical continuity of (28) is achieved. The positive electrode lead (3A) is formed of aluminum foil, and the negative electrode lead (3A) is formed.
(3B) is formed from copper foil.

As shown in FIG. 2, the tip portions (31) of a plurality of positive electrode leads (3A) drawn out from the wound electrode body (2).
Is connected to one electrode terminal mechanism (4) serving as a positive electrode terminal. Similarly, tips (31) of a plurality of negative electrode leads (3B) drawn out from the winding electrode body (2) are connected to the other electrode terminal mechanism (4) serving as a negative electrode terminal. by this,
The power generated by the winding electrode body (2) can be taken out from the pair of positive and negative electrode terminal mechanisms (4) and (4).

As shown in FIG. 7, the lid (12) has a through hole (14) at the center and a screw hole (15) at the outer periphery. The mechanism (4) is attached,
A gas discharge valve (13) is screwed into the screw hole (15).

The electrode terminal mechanism (4) has a structure shown in FIG. 2 and FIG. That is, as shown in FIG. 2, a pair of insulating packings (8) and (81) are attached to the through hole (14) of the lid (12) in a state where they are engaged with each other. As shown in FIG. 7, the upper insulating packing (8) is formed of a disk portion (85) and a cylindrical portion (86), while the lower insulating packing (81) is formed in a ring shape and engaged with each other. In the state, the through hole of the lid (12)
(14) Close contact with the inner peripheral surface and inner peripheral edge.

The holding member (5) is inserted from the outside of the lid (12) into the center hole of the pair of insulating packings (8) and (81) mounted in the through hole (14) of the lid (12). You. The holding member (5) is integrally provided with a hexagonal prism screwing operation part (51) at the head of the screw shaft part (52), and has a concave part (25) of the winding core (20) at the lower end surface.
A convex portion (53) that can be fitted into is formed. Holding member (5)
A screw nut (6) and a terminal nut (61) are screwed into the screw shaft portion (52) from outside the lid (12), and the lid (1
From the inside of 2), the second clamping nut (7) is screwed, and the insulating packings (8) and (81) are compressed by the first clamping nut (6) and the second clamping nut (7). Have been. Also, an O-ring (82) is provided between the opposing surfaces of the lid (12) and the disk portion (85) of the insulating packing (8).
And an O-ring (83) is interposed between the disk portion (85) of the insulating packing (8) and the opposing surface of the clamping nut (6).

As shown in FIG. 2, the end face of the winding core (20) and the tip end face of the holding member (5) are pressed against each other, and are held in a recess (25) formed on the end face of the winding core (20). A convex portion (53) formed on the distal end surface of the member (5) is fitted. by this,
The wound electrode body (2) has both ends of the winding core (20) pressed by both ends by a pair of holding members (5) and (5), and is firmly fixed in the battery can (1). I have. The tip portions (31) of the plurality of positive electrode leads (3A) extending from the winding electrode body (2) are connected to one end surface of the winding core (20) and a holding member on the positive electrode side.
The electrode terminal mechanism on the positive electrode side sandwiched between the tip surfaces of (5)
The electrical connection with (4) is made. Similarly, the tips (31) of the plurality of negative electrode leads (3B) extending from the winding electrode body (2) are connected to the other end face of the winding core (20) and the tip of the holding member (5) on the negative electrode side. It is sandwiched between the surfaces, and is electrically connected to the electrode terminal mechanism (4) on the negative electrode side.

In the manufacturing process of the cylindrical lithium secondary battery, first, a wound electrode body (2) shown in FIG. 3 is manufactured. As described above, the positive electrode containing the lithium composite oxide (21)
And a negative electrode (23) containing a carbon material, a separator (22) is interposed therebetween, and a plurality of positive electrode leads (3A) and a plurality of negative electrode leads (3B) are sandwiched at predetermined positions, respectively, and these are wound around a core (20). Spirally wound around the outer peripheral surface of.

In the winding operation, as shown in FIG. 6, first, the tip of the separator (22) is wound around the outer peripheral surface of the winding core (20) a plurality of times. Here, a slit (24) through which the distal end of the separator (22) is to be inserted is opened in the winding core (20), and the winding is performed with the distal end of the separator (22) inserted through the slit (24). By rotating the core (20), the tip of the separator (22) can be wound around the outer peripheral surface of the core (20). Therefore, it is not necessary to adhesively fix the tip of the separator (22) to the outer peripheral surface of the winding core (20), and the winding operation is easy. Also, the outermost peripheral surface of the wound electrode body (2)
Covered by separator (22).

Next, as shown in FIG. 8, the cylindrical body of the battery can (1)
(11) The winding electrode body (2) is accommodated in the winding electrode body.
Tip portions (31) of a plurality of positive electrode leads (3A) extending from (2)
Is engaged with one end face of the winding core (20). Further, the tips (31) of the plurality of negative electrode leads (3B) extending from the winding electrode body (2) are engaged with the other end face of the winding core (20) (not shown). Further, the electrode terminal mechanism (4) is fixed to each lid (12). Here, the first pressing nut (6) and the second pressing nut
(7) is tightened until sufficient liquid tightness is obtained by the insulating packings (8) and (81).

Thereafter, the lids (12) and (12) are welded and fixed to both openings of the cylindrical body (11) using laser welding or beam welding. As a result, as shown in FIG. 2, the distal end surface of the sandwiching member (5) of the electrode terminal mechanism (4) comes into contact with each end surface of the winding core (20), or faces at a slight interval.
In this state, the holding members (5) of the two electrode terminal mechanisms (4) (4)
By screwing (5), both end faces of the winding core (20) are sandwiched from both sides by the distal end faces of both holding members (5) and (5), and both end faces of the winding core (20) and the holding members (5 And (5), the tip portions (31) of a plurality of positive electrode leads (3A) and negative electrode leads (3B) are sandwiched.

Then, the battery can is inserted through the screw hole (15) of the lid (12).
An electrolyte is injected into (1). Thereby, the resin sheet (200) in the wound electrode body (2) absorbs the electrolyte and expands. As a result, the winding state of the positive electrode (21), the separator (22), and the negative electrode (23) constituting the winding electrode body (2) becomes tight, and the winding hardness increases.

The wound electrode body (2) is made of a resin sheet (2).
2 expands by absorbing the non-aqueous electrolyte, and its outer diameter increases. As shown in FIG. 2, the outer peripheral surface of the wound electrode body (2) becomes cylindrical (11) of the battery can (1). ). As a result, the wound electrode body (2) is fixed inside the battery can (1). Here, since the winding core (20) is tightly fitted into the center of the winding electrode body (2), the deformation toward the center of the winding electrode body (2) is prevented by the winding core (20). Will be blocked. As a result, the wound electrode body (2) expands outward, and a large pressing force is generated between the outer circumferential surface of the wound electrode body (2) and the inner circumferential surface of the battery can (1), The wound electrode body (2) is securely fixed inside the battery can (1). Also, a large pressing force is generated between the winding electrode body (2) and the winding core (20), and both are firmly fixed to each other.

Finally, as shown in FIG. 1, a gas discharge valve (13) is screwed and fixed to each lid (12) to complete the cylindrical lithium secondary battery according to the present invention.

According to the cylindrical lithium secondary battery of the present invention, since the resin sheet (200) absorbs the electrolyte and the winding solidity of the winding electrode body (2) increases, vibration and external Even if an impact is applied, there is no possibility that the winding electrode body (2) may be broken. In addition, winding electrode body (2)
Is firmly supported at its center by the winding core (20), and at the same time, is pressed against the inner peripheral surface of the battery can (1) on the outer peripheral surface,
Because it is firmly fixed inside the battery can (1), even if vibration or impact is applied from the outside, the winding electrode body (2)
However, there is no risk of displacement of the battery inside the battery can (1).

The above-mentioned cylindrical lithium ion secondary batteries of the present invention (Batteries 1 to 9 of the present invention) and comparative batteries not provided with a resin sheet were produced and their performance was evaluated. First, a common manufacturing process for each battery will be described, and then a different assembly process for each battery will be described.

[0034]Preparation of positive electrode  LiCoO having an average particle size of 5 μm as a positive electrode active material₂(Re
Composite oxide) powder, and artificial graphite as a conductive agent.
Were mixed at a weight ratio of 9: 1 to prepare a positive electrode mixture. Next
In addition, polyvinylidene fluoride as a binder is N-methyl-
2 Dissolve in pyrrolidone (NMP) to prepare NMP solution
did. Then, the weight of the positive electrode mixture and polyvinylidene fluoride
Mix the positive electrode mixture and the NMP solution so that the ratio becomes 95: 5.
Thus, a slurry was prepared. And this slurry is thick
Doctor blade method on both sides of 20μm aluminum foil
4 and dried at 150 ° C. for 2 hours.
The positive electrode (21) shown in the following was obtained.

[0035]Fabrication of negative electrode  Carbon lump (d₀₀₂= 3.356Å; Lc> 1000)
Air current is injected and pulverized, and carbon powder as a negative electrode active material is
Obtained. In addition, polyvinylidene fluoride as a binder is replaced with NMP
To prepare an NMP solution, carbon powder and
Carbon powder so that the weight ratio of vinylidene fluoride becomes 85:15
And an NMP solution were kneaded to prepare a slurry. Soshi
Then, two copper foils having a thickness of 20 μm are prepared, and the slurry is
Apply to one side of each copper foil by doctor blade method,
After vacuum drying at 50 ° C. for 2 hours, the negative electrode (2
3) was obtained.

[0036]Preparation of electrolyte  Volume ratio of ethylene carbonate and diethyl carbonate
LiPF was added to the solvent mixed at 1: 1.₆Of 1 mol / L
The mixture was dissolved at a ratio to prepare an electrolytic solution.

[0037]Separator  Polypropylene with ion permeability as a separator
A microporous membrane made of stainless steel was prepared.

[0038]Assembling the batteries 1 to 9 of the present invention  After winding the separator several times around a 10 mm diameter core, the positive electrode
As a separator (22) is interposed between (21) and the negative electrode (23),
Separator (22), positive electrode (21), separator (22), and negative electrode
(23), and two sheets of copper constituting the negative electrode (23)
8μm thick acrylic resin sheet between foils (28)
(200), and wind them in a spiral shape.
A wound electrode body (2) having a core (20) was produced. In addition, winding
In the winding process of the wound electrode body (2), as shown in FIG.
As shown, between the resin sheet (200) and the copper foil (28) (28),
50 μm, 2 cm wide nickel negative electrode lead (3B)
While sandwiching the base end, the positive electrode (21) and the separator (22)
Between them, an aluminum positive electrode with a thickness of 50 μm and a width of 2 cm
The base end of the pole lead (3A) was sandwiched.

The wound electrode body (2) thus obtained
Is loaded into the cylindrical body (11), and the positive electrode lead (3A) and the negative electrode lead (3B) extending from the winding electrode body (2) are respectively connected to the positive and negative electrode terminal mechanisms (4) and (4). After the connection, the lids (12) and (12) were welded and fixed to the openings at both ends of the cylindrical body (11), and the electrolyte was injected into the battery can (1), and the diameter was 57 m.
The battery 1 of the present invention having a length of 220 mm and a length of 220 mm was assembled. or,
The thickness of the resin sheet (200) is 3 μm, 5 μm, 7.5 μm,
10 μm, 25 μm, 50 μm, 75 μm, or 10
Except that the thickness is 0 μm, the same as the above-described battery 1 of the present invention,
The batteries 2 to 9 of the present invention were assembled.

[0040]Comparative example battery assembly  Furthermore, except that the resin sheet (200) is omitted,
A battery of the comparative example was assembled in the same manner as the battery 1 of the present invention.
Was.

[0041]Evaluation of output characteristics  For the batteries 1 to 9 of the present invention and the battery of the comparative example, the amplitude was 1 mm,
Vibration at a frequency of 10 to 55 Hz is generated at a sweep rate of 1 Hz / mi.
n for 100 minutes in the XYZ directions crossing each other at right angles,
Output characteristics (DOD: 50% discharge for 15 seconds
(The output density at the time of performing the above). And vibration
The difference in power density between before and after adding was determined. The results are displayed
1 and Table 2.

[0042]

[Table 1]

[Table 2]

As is clear from Table 1, the battery 1 of the present invention has a smaller decrease in output density than the battery of the comparative example. This is because, by sandwiching the resin sheet (200) between the winding electrode body (2) and the winding electrode body (2),
This is due to the fact that the winding electrode body (2) is securely fixed inside (1), thereby preventing the winding electrode body (2) from being broken or displaced.

Further, as is apparent from Table 2, when the thickness of the resin sheet is in the range of 5 to 50 μm, the decrease in the output density is 20%.
Although it is suppressed to not more than W / kg, the output density of a battery having a resin sheet thickness of 3 μm or less or a battery having a resin sheet thickness of 75 μm or more is more than 20 W / kg. This is because, when the thickness of the resin sheet is 3 μm or less, the winding electrode body is insufficiently fixed due to the expansion of the resin sheet, and the winding electrode body collapses due to vibration, or the winding core and the winding electrode body are not fixed. It is considered that as a result of the displacement between them, the contact state between the positive electrode lead and the positive electrode and between the negative electrode lead and the negative electrode deteriorated, and the current collecting performance was reduced. Also, the thickness of the resin sheet is 75 μm
In the above, excessive pressure acts on the wound electrode body due to the expansion of the resin sheet, and wrinkles are generated on the positive electrode and the negative electrode. As a result, the contact state between the positive electrode lead and the positive electrode and between the negative electrode lead and the negative electrode deteriorate. It is considered that the current collection performance was reduced.

[0045]Inventive battery B and its evaluation  The base end of the negative electrode lead (3B) shown in FIG.
Same as Battery 1 of the present invention except that spot welding is used for joining.
In this way, the battery B of the present invention was produced, and the same method as described above was used.
The output characteristics were evaluated. As a result, in the battery B of the present invention,
In this case, the decrease in power density is 15 W / kg,
A value equivalent to the decrease in power density in pond 1 (15 W / kg)
was gotten.

Therefore, the base end of the negative electrode lead (3B) is made of copper foil.
(28) Even if a joining structure that merely sandwiches is adopted without spot welding on (28), the deterioration in output characteristics due to vibration is small, and the adoption of the joining structure simplifies the manufacturing process. Is possible. Similarly, the manufacturing process of the positive electrode lead (3A) can be simplified by adopting a bonding structure in which the positive electrode lead (3A) is simply sandwiched between the wound electrode body (2).

[0047]Inventive battery C and its evaluation  The core (20) shown in FIG. 2 is omitted, and the positive electrode lead (3A) and
The tip (31) of the negative electrode lead (3B) is sandwiched between the electrode terminal mechanisms (4).
Battery 1 of the present invention except that it was welded to the end face of pressure member (5).
Similarly, a battery C of the present invention was produced, and the same method as described above was used.
The output characteristics were evaluated more. As a result, the battery C of the present invention
The power density is reduced by 20 W / kg.
Lower than the decrease in output density (15 W / Kg) in Battery 1
Although the amount of drying and the amount of
Significantly smaller decrease than force density (34 W / Kg)
It has gone down.

From this result, even when the winding electrode body (2) is not equipped with the winding core (20), the resin sheet
Winding electrode body due to vibration due to expansion of (200) (2)
Of the battery can (1) can be prevented, and a decrease in output density can be prevented.
In addition, when the winding electrode body (2) is equipped with the winding core (20) without the winding core, the winding electrode body (2) collapses due to the vibration and the battery can (1) It can be seen that the displacement of the output density can be prevented, and a decrease in the output density can be prevented.

As described above, according to the cylindrical lithium ion secondary battery of the present invention, the wound electrode body (2) is expanded by the expansion of the resin sheet (200) sandwiched between the wound electrode body (2). The winding state of the positive electrode (21), the separator (22) and the negative electrode (23) constituting the battery pack becomes tight, the winding hardness increases, and at the same time, the inside of the battery can (1) of the winding electrode body (2) Is secured, so that even if vibrations or shocks are applied from the outside, there is no danger that the winding electrode body (2) will be distorted or misaligned.
Power density is prevented from lowering.

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, as shown in FIG. 4 and FIG. 5, the joining structure of the negative electrode lead (3B) is one negative electrode lead.
Not limited to the structure in which the resin sheet (200) is sandwiched by (3B), between the resin sheet (200) and one copper foil (28), and between the resin sheet (200) and the other copper foil (28) Negative lead alternately (3
It is also possible to adopt a structure in which B) is interposed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the external appearance of a cylindrical lithium ion secondary battery according to the present invention.

FIG. 2 is a cross-sectional view illustrating an internal structure of the cylindrical lithium ion secondary battery.

FIG. 3 is a partially developed perspective view of a wound electrode body.

FIG. 4 is an enlarged sectional view illustrating a laminated structure of a positive electrode and a negative electrode.

FIG. 5 is an enlarged perspective view illustrating a joining structure of a negative electrode lead.

FIG. 6 is a perspective view showing a step of winding a separator around a winding core.

FIG. 7 is an exploded perspective view of an electrode terminal mechanism.

FIG. 8 is a cross-sectional view showing a battery assembly process.

FIG. 9 is a cross-sectional view illustrating a schematic structure of a conventional cylindrical nonaqueous electrolyte secondary battery.

[Explanation of symbols]

 (1) Battery can (11) Cylindrical body (12) Lid (2) Winding electrode body (20) Core (21) Positive electrode (26) Aluminum foil (27) Positive active material (22) Separator (23) Negative electrode (28) Copper foil (29) Negative electrode active material (3A) Positive electrode lead (3B) Negative electrode lead (32) Lead piece (33) Lead piece (200) Resin sheet (4) Electrode terminal mechanism

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Koichi Sato 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Toshiyuki Noma 2-chome Keihanhondori, Moriguchi-shi, Osaka No.5-5 Sanyo Electric Co., Ltd. (72) Inventor Ikuro Yonezu 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. 5H017 AA03 AS02 AS07 BB11 CC01 DD06 HH03 HH05 5H029 AJ11 AK03 AL06 AM01 AM02 BJ02 BJ14 CJ05 DJ02 DJ04 DJ05 DJ07 EJ12 HJ04

Claims (7)

[Claims] A wound electrode body (2) having a separator (22) interposed between a strip-shaped positive electrode (21) and a negative electrode (23) is housed inside a battery can (1). A non-aqueous electrolyte in which a non-aqueous electrolyte is injected and electric power generated by the wound electrode body (2) can be taken out from a positive electrode terminal portion and a negative electrode terminal portion provided in the battery can (1). In the secondary battery, a resin sheet (200) that expands by absorbing a non-aqueous electrolyte is wound on the winding electrode body (2) together with the positive electrode (21), the negative electrode (23), and the separator (22). Non-aqueous electrolyte secondary battery characterized by being used. 2. The resin sheet (200) is formed of a resin material mainly composed of an acrylic resin, or a resin material mainly composed of vinyl chloride, a vinyl chloride / vinyl acetate copolymer or a vinyl butyral resin. 2. The non-aqueous electrolyte secondary battery according to 1. 3. The non-aqueous electrolytic solution according to claim 1, wherein the resin sheet has a thickness in a range of not less than 5 μm and not more than 50 μm when the non-aqueous electrolytic solution is not absorbed. Liquid secondary battery. 4. A positive electrode (21) and a negative electrode of a wound electrode body (2)
Each of (23) is formed by forming an active material layer on the surface of a band-shaped core, and the core of at least one of the positive electrode (21) and the negative electrode (23) is formed by stacking two metal foils. The resin sheet (200) is interposed between both metal foils.
The non-aqueous electrolyte secondary battery according to claim 3. 5. A strip-shaped lead is interposed between a resin sheet (200) and the metal foil, and a tip of the lead is connected to a positive electrode terminal or a negative electrode terminal.
The non-aqueous electrolyte secondary battery according to any one of the above. 6. The resin sheet (200) absorbs the non-aqueous electrolyte, and the outer peripheral surface of the wound electrode body (2) is pressed against the inner peripheral surface of the battery can (1). Item 6. A non-aqueous electrolyte secondary battery according to any one of Items 5. 7. A winding core is provided in the center hole of the winding electrode body (2).
7. The non-aqueous electrolyte secondary battery according to claim 6, wherein (20) is densely penetrated.