JPH0992338A - Cylindrical secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a lead from being broken in a large-sized secondary battery. SOLUTION: In a cylindrical secondary battery in which an electrode spiral body 35 formed by spirally winding strip positive electrode and negative electrode through a separator is housed in a cylindrical battery case, leads 11 are provided extending from the respective current collectors 13a, 14a formed of metal foils of the positive electrode and the negative electrode on one side and the other side in the direction orthogonal to the winding direction. The leads 11 on the one side and the other side are connected to positive electrode terminals 20 and negative electrode terminals 21 with a prescribed deflection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical secondary battery preferably applied to a large-capacity cylindrical lithium ion secondary battery used as a power source for electric vehicles and the like.

[0002]

2. Description of the Related Art In a conventional cylindrical secondary battery, an electrode spiral body formed by spirally winding a strip-shaped positive electrode and a negative electrode through a separator is housed in a cylindrical battery case.

In this case, the winding start of the current collector of the strip-shaped positive electrode of the electrode spiral is connected to a winding core made of, for example, aluminum, and this winding core serves as a positive electrode terminal and the strip-shaped negative electrode of the electrode spiral. The end of winding of the current collector was connected to a battery case made of metal such as stainless steel, and this battery case was used as a negative electrode terminal.

[0004]

In such a conventional cylindrical secondary battery, since the winding start and winding end of the positive and negative electrode current collectors are connected to the electrode terminals, respectively, the positive and negative electrodes are respectively connected to the ends. Since the distance that the obtained electrons reach the electrode terminals is long, the internal resistance is relatively large, and especially when the size is increased, the length of the positive electrode and the negative electrode becomes long, and there is a disadvantage that the internal resistance further increases. It was

Therefore, it is conceivable to provide leads extending from one side and the other side of the current collector made of the metal foil of the positive electrode and the negative electrode, respectively, in the direction orthogonal to the winding direction.

However, since the secondary battery used for the power source of the electric vehicle is large in size and the electrode spiral itself is heavy and vibrates, there is a possibility that the lead may be broken.

In view of this point, the present invention has an object to prevent the leads from being broken in the large-sized secondary battery as described above.

[0008]

SUMMARY OF THE INVENTION A cylindrical secondary battery of the present invention is a cylinder in which an electrode spiral body in which a band-shaped positive electrode and a negative electrode are spirally wound via a separator is housed in a cylindrical battery case. In the rechargeable secondary battery, leads are provided by extending to one side and the other side of the current collector made of the metal foils of the positive electrode and the negative electrode, respectively, in a direction orthogonal to the winding direction. The side leads are connected to the positive electrode terminal and the negative electrode terminal with a predetermined amount of slack.

According to the present invention, since the leads of the electrode spiral body are connected to the positive electrode terminal and the negative electrode terminal with a certain amount of slack, the leads are not destroyed by vibration or the like.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An example in which the cylindrical secondary battery of the present invention is applied to a cylindrical lithium ion secondary battery will be described below with reference to the drawings.

In this example, as shown in FIG. 5, the electrode spiral member 35 is housed in a cylindrical battery container 17. As shown in FIGS. 2 and 3, the electrode spiral body 35 includes a strip-shaped negative electrode 14 and a strip-shaped positive electrode 13 which are separated from each other by a separator 30.
It is wound around the winding core 31 via.

Here, a method of manufacturing the negative electrode 14 will be described. As the active material of the negative electrode 14, petroleum pitch was used as a starting material, and a functional group containing oxygen was added in an amount of 10 to 20.
% (So-called oxygen cross-linking), and then heat-treated at 1000 ° C. in an inert gas stream to obtain a carbon material having properties close to those of glassy carbon.
A carbon material powder of 0 μm is used.

90 parts by weight of this carbon material powder and 10 parts by weight of polyvinylidene fluoride (PVDF) as a binder were mixed, and this mixture was dispersed in a solvent N-methylpyrrolidone to form a slurry. Negative electrode active material 14
b is a negative electrode current collector 14a made of a strip-shaped copper foil having a thickness of 10 μm.
Is uniformly applied to both surfaces of the negative electrode to prepare a negative electrode electrode original plate having a thickness of 180 μm, and is cut and formed in a strip shape leaving an uncoated portion to be a lead portion of the negative electrode 14 on a side portion. Negative electrode 1
The shape of No. 4 has a width of 383 mm, of which the coated portion is 348 mm and the uncoated portion is 35 mm. Also,
The length is 6940 mm.

The positive electrode 13 is manufactured by the following method.
That is, the powder of LiCoO _{2 having} an average particle size of 15 μm
1 part by weight and 6 parts by weight of graphite as a conductive agent,
Mix 3 parts by weight of vinylidene fluoride as a binder,
This mixture is dispersed in a solvent N-methylpyrrolidone to form a slurry, and the slurry-like positive electrode active material 13b is evenly applied to both surfaces of a positive electrode current collector 13a made of a strip-shaped aluminum foil having a thickness of 20 μm to obtain a thickness. A 150 μm original plate of the positive electrode is prepared, and is cut and formed in a strip shape, leaving an uncoated portion to be the lead portion of the positive electrode on the side. The positive electrode 13 has a width of 379 mm, of which 344 is the coated portion.
mm, the uncoated portion is 35 mm. Also, the length is 7
It is 150 mm.

In the above description, the positive electrode 13 and the negative electrode 1
No. 4 is applied to the positive electrode and negative electrode current collectors 13a and 14a, respectively, and the positive electrode and negative electrode active materials 13b and 14b are applied and then cut to have a predetermined size.
After applying b and 14b, it is possible not to cut in the width direction. At this time, the positive electrode and the negative electrode active materials 13b and 14b are hardly dropped off, and the internal short circuit due to the drop of the positive electrode active material 13b and the negative electrode active material 14b can be eliminated.

As shown in FIGS. 1A and 1B, the uncoated portions of the positive electrode 13 and the negative electrode 14 produced as described above have a width of 10 mm, a length of 30 mm and a pitch of 15 before winding.
The strip-shaped leads 11 are formed by cutting the strip into strips each having a length of mm and extending from the positive electrode current collector 13a and the negative electrode current collector 14a.
Here, the uncoated portions of the positive electrode 13 and the negative electrode 14 are cut over the entire length with the above-mentioned dimensions.

Here, the length of the strip-shaped lead 11 must be longer than the distance from one end and the other end of the positive electrode 13 and the negative electrode 14 to the positive electrode terminal 20 and the negative electrode terminal 21, respectively. The width of the strip-shaped lead 11 is set so that the total cross-sectional area of the strip-shaped lead 11 satisfies the maximum energization current value. Further, considering the bending of the strip-shaped leads 11, the width is preferably 10 mm or less. In addition, the rising portion of the base of the strip-shaped lead 11 is curved, for example, R = 1 mm to make it difficult to cut.

As shown in FIG. 3, the positive electrode 13, the negative electrode 14, and the separator 30 are stacked in the order of the positive electrode 13, the separator 30, the negative electrode 14, and the separator 30 and wound on a winding core 31 to form an electrode spiral body. 35 is formed. At this time, one example of the electrode spiral body 35 is the strip-shaped lead 11 of the positive electrode 13, and the other side is the strip-shaped lead 11 of the negative electrode 14, so that the strip-shaped leads 11 are located on opposite sides. I will wind it up.

The separator 30 has a thickness of 38 μm.
It is a polyethylene sheet in which minute holes are formed, which is cut into a size of 353 × 7600 mm.
Further, the winding core 31 has, for example, an outer diameter of 17 mm and an inner diameter of 1
It is a pure aluminum cylinder having a length of 4 mm and a length of 354 mm.

As described above, the winding core 3 of the electrode spiral body 35.
Since the strip-shaped leads 11 are taken out on both sides of 1, the electric current obtained by the electrode current collectors 13a and 14a can be taken out satisfactorily to the outside. Also, this strip-shaped lead 11
Is formed in the shape of an elongated strip, its deformation is easy, and this strip-shaped lead 11 can be easily connected to the positive electrode terminal 20 and the negative electrode terminal 21.

In this example, the positive electrode terminal 20 and the negative electrode terminal 21 respectively have disk-shaped portions 20a and 21a and columnar portions 20b and 21b protruding outward from the central portion thereof.

After winding the positive electrode 13, the negative electrode 14, and the separator 30 on the winding core 31, as shown in FIG. 2 (FIG. 2 shows the positive electrode side, the negative electrode side is the same). The strip-shaped lead portion 11 is pressed by the holding metal fittings 33 substantially uniformly over the entire circumference of the outer peripheral portions of the disk-shaped portions 20a and 21a of the positive electrode terminal 20 and the negative electrode terminal 21, respectively. In this case, the positive electrode terminal 20 is made of pure aluminum (A105
0), and the negative electrode terminal 21 is pure copper (C1100). The material of the holding metal fitting 33 is pure aluminum (A1050) on the positive electrode side and pure copper (C1100) on the negative electrode side.

After the strip-shaped leads 11 are pressed onto the outer peripheral portions of the disk-shaped portions 20a and 21a of the positive electrode terminal 20 and the negative electrode terminal 21 by the pressing metal fittings 33, the strip-shaped leads 11 of the disk-shaped portions 20a and 21a are pressed. Align and cut at the upper end face. After this, as shown in FIG.
Laser light is applied to the portions of the strip-shaped leads 11 that are pressed from the upper surfaces of a and 21a by the pressing metal fittings 33, and welding is performed over the entire circumferences of the disk-shaped portions 20a and 21a.

In this case, in this example, the electrode spiral body 35 is formed into a cylindrical battery container 17 as shown in FIGS.
The length of the strip-shaped lead 11 when it is stored in the battery container 17 is a predetermined amount, for example, a play amount A between the positive electrode terminal 20 and the negative electrode terminal 21 of the battery container 17 and the end face of the electrode spiral body A.
Only have slack.

To give this slack, as shown in FIGS. 8A and 8B, before connecting the strip-shaped lead 11 to the positive electrode terminal 20 (negative electrode terminal 21) by welding, the jig 4 as shown in FIG. 8A is used.
After being loosened by a predetermined amount using 0, the disc-shaped portion 20a
It may be welded to (21a) as described above, or, as shown in FIGS. 9A and 9B, the strip-shaped lead 11 having a predetermined length longer than the disk-shaped portion 20 of the positive electrode terminal 20 (negative electrode terminal 21) is previously formed.
Figure 9B after welding connection to a (21a) as described above.
A jig 40 is used as shown in FIG.

As described above, since the strip-shaped lead 11 extending from the electrode current collectors 13a and 14a and the positive electrode terminal 20 and the negative electrode terminal 21 are joined by welding and in a large area, the internal resistance is increased. Is low and the variation is small. Moreover, from the viewpoint of a large area, a battery having particularly excellent large current discharge characteristics can be obtained.

In this case, the strip-shaped lead 11 may be welded to the outer peripheral portions of the disk-shaped portions 20a and 21a by ultrasonic welding. At this time, as shown in FIG. 7, the strip-shaped leads 11 are arranged substantially evenly around the outer circumferences of the disk-shaped portions 20a and 21a, and the horn of the ultrasonic welding machine having the disc-shaped horn 36 is provided. 36 to the disc-shaped portion 20
Ultrasonic welding is performed by abutting on the entire circumference of the outer peripheral portions of a and 21a. Also in this case, the same effect as the above can be obtained.

The welded electrode spiral member 35 and the positive electrode terminal 20 and the negative electrode terminal 21 are connected to the backup ring 5 respectively.
1, a seal 8, a ceramic butting 6, a cap (top plate) 1, a ring 50, and a ceramic washer 5 are assembled, and a nut 7 is tightened.

After that, the electrode spiral body 35 to which the cap 1 and the like are attached is wrapped by a polyimide sheet which is an insulating sheet for 1 to 3 times, and is covered with an adhesive tape to form a cylindrical battery container 17. To store.

In this case, as shown in FIG. 2, the cap 1
The outer circumference of is pressed into the cylindrical battery container 17 and laser welded. That is, the upper surface of the cap 1 is irradiated with a laser beam on the circumference thereof, and the cap 1 is sealed by welding.
In this way, by welding the cap 1 of the cylindrical battery container 17 with laser light, a battery having a completely sealed structure can be obtained.

The material of the battery container 17 is stainless steel (SUS304) and its wall thickness is 0.3 to 0.5.
mm. The material of the cap 1 is also stainless steel (SUS304), and its wall thickness is 3 mm.
It is.

As can be seen from FIGS. 2 and 5, the positive electrode terminal 2
A male screw (male screw portion 15) of M14 is cut on the outside of the cylindrical portions 20b and 21b of the 0 and the negative electrode terminal 21.
The nut 7 is arranged on the male screw portion 15. By tightening the nut 7, the cap 1 is sandwiched between the ceramic washer 5 and the ceramic butting 6, and the positive electrode terminal 20 and the negative electrode terminal 21 are similarly fixed to the cap 1. Further, a seal 8 made of, for example, a fluororesin is sandwiched between each of the disk-shaped portions 20a and 21a of the positive electrode terminal 20 and the negative electrode terminal 21 and the cap 1 to seal the electrolyte solution so as not to leak.

In addition, M6 is provided in the central portion of each of the cylindrical portions 20b and 21b of the positive electrode terminal 20 and the negative electrode terminal 21, respectively.
The female screw (female screw portion 16) is cut. The female screw portion 16 is used when connecting to the outside. That is, by screwing a bolt 19 into the female threaded portion 16, a bus bar or a conductor wire is sandwiched between the end surfaces of the tip ends of the positive electrode terminal 20 and the negative electrode terminal 21 and the head portion of the bolt 19 for connection. Fix it.

As shown in FIG. 1, the winding core 31 is insulated from the positive electrode terminal 20 and the negative electrode terminal 21 by an insulating collar 12 made of polypropylene (PP).

As shown in FIGS. 2 and 4, the ceramic washer 5 is in the shape of a disk having a circular hole in the center thereof, and is sandwiched between the nut 7 and the cap 1. The material of this ceramic washer 5 is alumina (Al
₂ O ₃ ).

The purpose of the ceramic washer 5 is to insulate the positive electrode terminal 20 and the negative electrode terminal 21 from the cap 1, respectively, but since the material thereof is alumina as described above, the insulating property can be ensured. .

The positive electrode terminal 20 and the negative electrode terminal 21 are
Since each is fixed to the cap 1 by tightening the nut 7, the ceramic washer 5 must have sufficient rigidity to withstand this fastening force, that is, the compression force. Also in this respect, since the material of the ceramic washer 5 is alumina, it is possible to sufficiently withstand the compressive force of the nut 7. Further, since the material is alumina, its shape does not change even after a long period of time after fastening, so that a strong fastening force can be maintained. Further, since the rigidity of alumina does not change even when the temperature changes, the fastening force can be maintained even if the temperature changes in a wide range.

Furthermore, since alumina has a very high rigidity, the nut 7 can be tightened more strongly. As a result, a large fastening force can be obtained, the nut 7 does not loosen over time due to vibrations generated in the vehicle, and a sufficient seal can be obtained, preventing leakage of the non-aqueous electrolyte. Can maintain the hermeticity.

Between the ceramic washer 5 and the ceramic abutment 6, and inside the cap 1 and the positive electrode terminal 20.
A ring 50 is arranged between the outer side of the negative electrode terminal 21 and the outer side of the negative electrode terminal 21. The ring 50 has a rectangular cross section and is made of a polymer material such as PP. The ring 50 holds the central axes of the positive electrode terminal 20 and the negative electrode terminal 21 at the central axis in the longitudinal direction of the battery when the positive electrode terminal 20 and the negative electrode terminal 21 are fixed to the cap 1 by tightening the nut 7. Is used for.

A ceramic abutment 6 is sandwiched between the inner surface of the cap 1 and the disk-shaped portions 20a and 21a of the positive electrode terminal 20 and the negative electrode terminal 21, respectively. Similar to the ceramic washer 5, the ceramic abutment 6 has a disk shape having a circular hole in the center thereof, and the material thereof is alumina (Al ₂ O ₃ ).

Like the ceramic washer 5, this ceramic abutment 6 ensures the insulation between the positive electrode terminal 20 and the negative electrode terminal 21 and the cap 1. Further, the ceramic abutment 6 can sufficiently withstand the compression force of the nut 7. Further, a strong fastening force can be maintained even after a long time has passed after fastening. Further, the ceramic abutment 6 can maintain its fastening force even if the temperature changes in a wide range. Furthermore, the ceramic abutment 6 can obtain a large fastening force, and the nut 7 does not loosen with time due to vibration generated in the vehicle, and a sufficient seal can be obtained. It can be prevented from leaking.

In addition, the ceramic abutment 6 has its outer circumference set at a position where the elastic deformation of the seal 8 does not occur to a certain extent or more, so that the large elastic deformation of the seal 8 is prevented, and as a result, the seal 8 is prevented. Positive terminal 2
0 and the axial repulsion force of the negative electrode terminal 21 can be increased. By arranging the ceramic abutment 6 in this manner, the sealing force of the seal 8 can be increased to a sufficient magnitude.

A backup ring 51 is arranged on the outer periphery of the seal 8 at a position in contact with the seal 8. The backup ring 51 is made of PP. When the seal 8 comes into contact with the non-aqueous electrolyte existing in the battery and is swollen and deformed by the backup ring 51, the deformation is blocked to repel the positive electrode terminal 20 and the negative electrode terminal 21 of the seal 8 in the axial direction. It is possible to prevent the power from decreasing.

As shown in FIGS. 2 and 4, an opening valve 9 is installed at a position off the center of the cap 1. The release valve 9 is screwed and fixed in a hole provided in the cap 1. The release valve 9 is for releasing the gas inside when the pressure inside the battery container rises.

The valve arranged in the open valve 9 is pressed against the inside of the battery by a spring to make the inside of the battery liquid-tight.

When the pressure inside the battery rises for some reason, the valve in the release valve 9 is pressed to the outside of the battery.
As a result, the gas inside the battery is discharged to the outside through the gap formed by the movement of the valve and through the hole provided on the side surface of the open valve 9. By installing this release valve 9, even if the pressure inside the battery rises, it is possible to prevent the pressure from exceeding a certain level.

As shown in FIG. 2, an electrolytic solution inlet 32 is provided at a position off the center of the cap 1. The electrolytic solution inlet 32 is used to inject the electrolytic solution into the battery after the battery structure is assembled.

Further, as shown in FIGS. 2 and 4, a blind plug 4 is arranged at a position of the electrolyte injection port which is off the center of the cap 1. This blind plug 4 has an electrolyte injection port 3
It is screwed to the battery 2 via the metal seal 2 to seal the battery container 17.

A metal seal 2 is sandwiched between the head of the blind plug 4 and the surface of the cap 1.
The metal seal 2 is a ring having a rectangular cross section, and its material is pure aluminum.

On the other hand, the metal parts in contact with the metal seal 2 are the head of the battery cap 1 and the blind plug 4, which are made of stainless steel (SUS304).

It has been confirmed that even if two kinds of metals, stainless steel and pure aluminum, are brought into contact with each other and brought into contact with the non-aqueous electrolyte of the lithium ion secondary battery, the corrosion of pure aluminum does not proceed.

As described above, by using the metal seal made of pure aluminum, as compared with the seal made of a polymer material such as a rubber material, the permeability of gas and moisture to the outside can be improved.
Passability can be suppressed to a low level, and battery life can be extended. Also, since pure aluminum has a longer life than polymer materials, it can be used semi-permanently if a metal seal made of pure aluminum is used for the seal of the blind plug.
No need to replace the seal. Further, as shown in FIG. 2, a metal seal made of pure aluminum can be used for the above-mentioned seal of the open valve 9.

The method of injecting the non-aqueous electrolyte into the battery container 17 will be described below. First, the injection attachment is screwed and fixed in the electrolyte injection port 32. As a result, the nonaqueous electrolytic solution stored in the electrolytic solution (EL) tank and the battery container are connected through the pipe. The part of the space higher than the liquid surface of the non-aqueous electrolyte in this electrolyte tank is
It is connected to a vacuum pump via a switching valve.

The electrolytic solution used in this example was formed by dissolving LiPF ₆ in a mixed solvent of propylene carbonate and diethyl carbonate at a ratio of 1 mol / l.

Next, the vacuum pump is operated. When the vacuum pump operates, the air inside the battery is discharged to the outside of the battery container, and the inside of the battery container becomes a negative pressure compared to the atmospheric pressure.

Next, the switching valve provided between the vacuum pump and the electrolytic solution tank is switched to open the liquid surface of the electrolytic solution tank to the atmosphere. Then, the pressure in the tank becomes higher than that in the battery container, so that the nonaqueous electrolytic solution in the tank is pushed out and enters the battery container.

By repeating the above steps several times, a predetermined non-aqueous electrolyte can be injected into the battery container.

After the injection of the non-aqueous electrolytic solution, it is necessary to seal the electrolytic solution so that the electrolytic solution does not flow out of the battery container. Therefore, the blind plug 4 is screwed into the electrolytic solution inlet 32 via the metal seal 2 to seal the battery container 17.

As described above, according to this example, the positive electrode 13
And a plurality of strip-shaped leads 11 at a predetermined interval, for example, extending to one side and the other side of the positive electrode and negative electrode current collectors 13a and 14a of the negative electrode 14 in the direction orthogonal to the winding direction and at predetermined intervals. Since the plurality of strip-shaped leads 11 on one side and the other side are connected to the positive electrode terminal 20 and the negative electrode terminal 21, respectively, the positive electrode and the negative electrode current collectors 13a and 14a can be connected to the positive electrode terminal 20 and the negative electrode terminal 21 from anywhere. Is relatively close, the internal resistance is relatively small,
There is an advantage that it is not necessary to thicken the positive and negative electrode current collectors 13a and 14a even when the secondary battery is increased in size (capacity is increased), and there is an advantage that the size can be reduced accordingly.

Further, according to this example, the strip-shaped leads 1 of the positive electrode 13 and the negative electrode 14 of the electrode spiral 35 are provided on the disk-shaped portions 20a and 21a of the positive electrode terminal 20 and the negative electrode terminal 21, respectively.
Since 1 is welded by laser welding or ultrasonic welding,
It has good advantages in that it is well bonded in a wide area, has a low internal resistance, has small variations, and has a low internal resistance, and thus has excellent large current discharge characteristics.

Further, according to this example, since the strip-shaped lead 11 of the electrode spiral member 35 is connected to the positive electrode terminal 20 and the negative electrode terminal 21 with slack by the play A in the cylindrical direction, the strip-shaped lead 11 is There is an advantage that it will not be destroyed by vibration.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0063]

According to the present invention, since the leads of the electrode spiral body are connected to the positive electrode terminal and the negative electrode terminal with a predetermined amount of slack, there is an advantage that the leads are not broken by vibration or the like.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a main part of an embodiment of a cylindrical secondary battery of the present invention.

FIG. 2 is a cutaway sectional view showing a main part of an embodiment of a cylindrical secondary battery of the present invention.

FIG. 3 is a diagram used to explain a main part of the example of FIG. 2;

FIG. 4 is a side view of the example of FIG.

FIG. 5 is a cross-sectional view showing an embodiment of the cylindrical secondary battery of the present invention.

FIG. 6 is a diagram for explaining an example of the present invention.

FIG. 7 is a diagram provided for explaining an example of the present invention.

FIG. 8 is a diagram provided for explaining an example of the present invention.

FIG. 9 is a diagram provided for explaining an example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cap (top plate) 4 Blind plug 9 Open valve 11 Strip-shaped lead 13 Positive electrode 13a Positive electrode current collector 14 Negative electrode 14a Negative electrode current collector 17 Battery container 20 Positive electrode terminal 21 Negative electrode terminal 30 Separator 31 Core core 32 Electrolyte injection Inlet 33 Holding fitting 35 Electrode spiral body 40 Jig

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideya Takahashi, Hideya Takahashi, Koriyama City, Fukushima Prefecture, Takakura, Higashida Town, Fukushima Prefecture, 1st part of Shimosugishita, Sony Energy Tech Co., Ltd. (72) Yosuke Kita, Shinagawa-ku, Kitagawa Shinagawa, Tokyo 6-735 Sony Corporation (72) Inventor Kiyoshi Katayama 1 at Shimosugishita, Takakura, Hiwada-cho, Koriyama-shi, Fukushima 1 Sony Energy Tech Co., Ltd.

Claims (4)

[Claims] 1. A cylindrical secondary battery in which an electrode spiral body in which a strip-shaped positive electrode and a negative electrode are spirally wound via a separator is housed in a cylindrical battery case, wherein the positive electrode and the negative electrode are Leads are provided on one side and the other side of the current collector made of the respective metal foils in a direction orthogonal to the winding direction, and leads are respectively provided on the one side and the other side at the positive electrode terminal and the negative electrode terminal, respectively. A cylindrical secondary battery characterized by being connected with a certain amount of slack. 2. The cylindrical secondary battery according to claim 1, wherein the leads are a plurality of strip-shaped leads arranged at predetermined intervals. 3. The cylindrical secondary battery according to claim 1, wherein a predetermined amount of slack in the lead is formed before connection to the positive electrode terminal and the negative electrode terminal. 4. The cylindrical secondary battery according to claim 1 or 2, wherein a predetermined amount of slack in the lead is formed after connecting to the positive electrode terminal and the negative electrode terminal. .