JP3363708B2 - Rechargeable battery - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary battery in which a group of electrodes wound spirally between a positive electrode and a negative electrode via a separator is housed in a battery container, and particularly used for an electric vehicle or the like. In doing so, have a large battery capacity,
In addition, it is characterized in that it can be stably used for a long period in a secondary battery that is charged and discharged with a large current.

[0002]

2. Description of the Related Art In recent years, secondary batteries have come to be used in various fields due to the development of various devices and the demand for clean energy, and high output, high energy density, and stable use over a long period of time. There has been a demand for the development of a secondary battery that can be used.

In recent years, air pollution caused by exhaust gas from automobiles has become a global problem, and with the progress of development of electric vehicles using electricity as a power source for automobiles,
Development of a secondary battery suitable for use in such an electric vehicle has been demanded.

Here, in an electric vehicle or the like which uses electricity as a power source, it is necessary to stably obtain a large amount of electric power over a long period of time, and as a secondary battery used in such an electric vehicle or the like. It is required that the battery has a large capacity and that charging and discharging can be stably performed with a large current.

Here, as shown in FIG. 1, a conventional secondary battery generally used is a positive electrode 1 in which a positive electrode material 1b is attached to a positive electrode current collector 1a, and a negative electrode material in a negative electrode current collector 2a. The electrode group wound in a spiral shape with the separator 3 interposed between the negative electrode 2 to which 2b is attached is composed of a battery can 4a to be the negative electrode terminal 4a and a battery lid 4b to be the positive electrode terminal 4b. The positive electrode 1
The positive electrode current collector tab 5 attached to the positive electrode current collector 1a is welded to the inner surface of the battery lid 4b, and the negative electrode current collector tab 6 attached to the negative electrode current collector 2a of the negative electrode 2 is attached to the bottom surface of the battery can 4a. It was made to weld to the part.

However, in the secondary battery as described above, the current only flows through the positive electrode current collecting tab 5 and the negative electrode current collecting tab 6 having the small area as described above, so that the battery in such a secondary battery is When the capacity is increased and charging / discharging is performed with a large current, the temperature of the positive electrode current collecting tab 5 or the negative electrode current collecting tab 6 rises due to this current, and the positive electrode current collecting tab 5 or the negative electrode current collecting tab 5 also rises. The temperature of the positive electrode 1 and the negative electrode 2 to which 6 is connected also rises, and the positive electrode material 1b and the negative electrode material 2b attached to the positive electrode current collector 1a and the negative electrode current collector 2a are removed from these current collectors 1a and 2a. There is a problem that the secondary battery is peeled off, the charge / discharge characteristics and cycle characteristics of the secondary battery are deteriorated, and the secondary battery cannot be stably used for a long period of time.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above problems in a secondary battery in which a group of electrodes wound spirally between a positive electrode and a negative electrode is housed in a battery container. The task is to
When using the secondary battery as described above in an electric vehicle or the like, even when the battery capacity is increased and charging / discharging is performed with a large current, the positive electrode and the negative electrode are partially heated. Stable over a long period of time without the positive electrode material attached to the positive electrode current collector and the negative electrode material attached to the negative electrode current collector peeling off from the respective current collectors to deteriorate charge / discharge characteristics and cycle characteristics. The problem is to be able to use it.

[0008]

In the secondary battery according to the present invention, in order to solve the above problems, a positive electrode having a positive electrode material attached to a positive electrode current collector and a negative electrode material provided on a negative electrode current collector. In a secondary battery in which an electrode group formed in a multilayer shape with a separator interposed between the attached negative electrode and a battery container is housed in a battery container, the positive electrode material is attached to the end of the positive electrode current collector to which the positive electrode material is attached. In addition to providing a non-adhered portion, a negative electrode current collector end to which the negative electrode material is attached is provided with a negative electrode material non-adhered portion, and the positive electrode current collector portion where the positive electrode material is not attached is used as a positive electrode terminal. Along with the pressure bonding, the negative electrode current collector portion to which the negative electrode material was not attached was pressure bonded to the negative electrode terminal.

Then, as in the secondary battery of the present invention, the portion of the positive electrode current collector to which the positive electrode material is not attached is crimped to the positive electrode terminal, and the portion of the negative electrode current collector to which the negative electrode material is not attached is removed. When pressure is applied to the negative electrode terminal, current will flow through these current collectors, and the area of the current flowing area will be much larger than when current flows through the positive electrode current collecting tab or the negative electrode current collecting tab. Even when the battery capacity of the secondary battery is increased and charging / discharging is performed with a large current, it is less likely that the positive electrode material and the negative electrode material are partially heated and the positive electrode material and the negative electrode material are separated from the respective current collectors. As a result, a secondary battery having stable charge / discharge characteristics and excellent cycle characteristics can be obtained.

Here, in providing the portion where the positive electrode material or the negative electrode material is not attached to the positive electrode current collector or the negative electrode current collector as described above, the width of the portion where the positive electrode material or the negative electrode material is not attached is reduced. If too much, it is impossible to secure a sufficient contact area when crimping the portion where the positive electrode material or the negative electrode material is not attached to each of the current collectors to the negative electrode terminal or the positive electrode terminal as described above. When charging and discharging with a large current as described above, the part where these current collectors contact the positive electrode terminal and the negative electrode terminal becomes hot, and the positive electrode material or the positive electrode material attached to these current collectors as described above. While the negative electrode material peels off and the charge / discharge characteristics and cycle characteristics deteriorate,
If the width of the portion to which the positive electrode material or the negative electrode material is not attached is too large, the area of the electrode portion to which the positive electrode material or the negative electrode material is attached becomes small, and the charging / discharging characteristics are deteriorated. Since the negative electrode material is deteriorated and the cycle characteristics and the like are deteriorated, it is preferable that the width of the portion where the positive electrode material and the negative electrode material are not adhered is within the range of 1 to 10 mm.

When the positive electrode current collector portion to which the positive electrode material is not attached and the negative electrode current collector portion to which the negative electrode material is not attached are pressure-bonded to the positive electrode terminal and the negative electrode terminal, these current collector and positive electrode In order to make sufficient contact with the terminal and the negative electrode terminal, it is preferable to provide a current collecting net or a conductive paste on the positive electrode terminal and the negative electrode terminal where these current collectors are crimped. The current collector network provided on the positive electrode terminal is made of aluminum or stainless steel, while the current collector network provided on the negative electrode terminal is made of stainless steel, copper or nickel. Also,
As the conductive paste, a paste made by binding a conductive agent such as graphite with a binder can be used.

Further, in the secondary battery according to the present invention, in the positive electrode and the negative electrode as described above, the portions of the positive electrode current collector and the negative electrode current collector to which the positive electrode material and the negative electrode material are not attached are respectively the positive electrode terminal and the negative electrode. It is effective for a secondary battery that has a large battery capacity and is charged and discharged with a large current because it is crimped to the terminal and the area where the current flows is large. It is a large battery with a battery capacity of 5 Wh or more. Next battery,
In particular, it can be effectively used in a large secondary battery having a battery capacity of 50 Wh or more.

Here, in the secondary battery of the present invention, the material used for the positive electrode and the negative electrode is not particularly limited,
It can be applied to various types of secondary batteries, for example,
It can be used for lithium secondary batteries, nickel-hydrogen secondary batteries, nickel-cadmium secondary batteries, and the like.

When the secondary battery of the present invention is a lithium secondary battery, a known positive electrode material capable of inserting and extracting lithium ions can be used as the positive electrode material used for the positive electrode. For example, manganese,
A lithium transition metal composite oxide containing at least one of cobalt, nickel, iron, vanadium, and niobium can be used. Also, as the negative electrode material used for the negative electrode, a known negative electrode material can be used, for example,
In addition to metallic lithium and lithium alloys, carbon materials such as graphite that can store and release lithium ions can be used. Furthermore, the non-aqueous electrolytic solution used as the electrolyte can also be a known non-aqueous electrolytic solution that has been conventionally used, as the solvent, for example, ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, cyclo Pentanone, sulfolane, dimethylsulfolane, 3-methyl-1,3-
Oxazolidin-2-one, γ-butyrolactone, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, butyl methyl carbonate, ethyl propyl carbonate, butyl ethyl carbonate, dipropyl carbonate,
1,2-dimethoxyethane, tetrahydrofuran, 2-
One or a combination of two or more organic solvents such as methyltetrahydrofuran, 1,3-dioxolane, methyl acetate and ethyl acetate can be used. Further, as the solute to be dissolved in such a solvent, for example, LiP
F ₆ , LiBF ₄ , LiClO ₄ , LiCF ₃ SO ₃ ,
_{LiAsF 6, LiN (CF 3 SO} 2) 2, LiOSO
Lithium compounds such as ₂ (CF ₂ ) ₃ CF ₃ can be used.

When the secondary battery according to the present invention is a nickel-hydrogen secondary battery, nickel hydroxide or nickel oxyhydroxide can be used as the positive electrode material for the positive electrode, and it can also be used for the negative electrode. As the negative electrode material to be used, a misch metal (hereinafter abbreviated as Mm) -based hydrogen storage alloy, or a Lavas phase alloy such as titanium-nickel-based alloy can be used.

When the secondary battery of the present invention is a nickel-cadmium secondary battery, nickel hydroxide or nickel oxyhydroxide can be used as the positive electrode material used for the positive electrode, and the negative electrode thereof can be used. For the negative electrode material used, use cadmium or cadmium hydroxide,
It is particularly effective when this cadmium or cadmium hydroxide is made into a paste and attached to the negative electrode current collector.

[0017]

EXAMPLES Hereinafter, the secondary battery according to the present invention will be specifically described with reference to Examples, and in the case where the battery capacity is increased and charging / discharging is performed with a large current, the secondary battery according to this Example is described. It will be clarified by using comparative examples that the battery can be stably used for a long period of time. The secondary battery according to the present invention is not limited to the ones shown in the following examples, and can be implemented with appropriate modifications within the scope of the invention.

(Examples 1 to 8) In these examples, the positive electrode, the negative electrode and the non-aqueous electrolyte prepared as described below were used, and the diameter was 20 mm, the height was 100 mm, and the battery capacity was about 10 Wh. A cylindrical lithium secondary battery as shown in FIG. 2 was manufactured.

[Production of Positive Electrode] In producing the positive electrode, lithium-containing cobalt dioxide (L
iCoO ₂ ) was used to mix the LiCoO ₂ and artificial graphite as a conductive agent in a weight ratio of 9: 1 to obtain a positive electrode mixture. Then, polyvinylidene fluoride, which is a binder, is added to the N
-Methyl-2-pyrrolidone (hereinafter abbreviated as NMP) is kneaded with an NMP solution dissolved in the above positive electrode mixture,
The weight ratio of the positive electrode mixture and polyvinylidene fluoride is 95: 5.
Was prepared, and the slurry was applied to both surfaces of an aluminum foil as a positive electrode current collector by the doctor blade method, and this was vacuum dried at 150 ° C. for 2 hours to produce sheet-shaped positive electrodes. .

When the positive electrode current collector is coated with the slurry containing the positive electrode material as described above, a positive electrode is prepared.
In these examples, the positive electrode current collector was provided with a portion not coated with the above-mentioned slurry, and the width of the portion not coated with the slurry on the positive electrode current collector was determined as shown in Table 1 below. 0.5 mm, 1 mm in Example 2, 2 mm in Example 3, 3 mm in Example 4, 5 mm in Example 5, 8 mm in Example 6, 10 mm in Example 7,
In Example 8, it was 12 mm.

[Preparation of Negative Electrode] In preparing a negative electrode, graphite powder was used as a negative electrode material, and an NMP solution prepared by dissolving polyvinylidene fluoride as a binder in NMP was kneaded with the above graphite powder. A slurry in which the weight ratio of graphite powder to polyvinylidene fluoride was 85:15 was prepared, and this slurry was applied to both surfaces of a copper foil, which is a negative electrode current collector, by a doctor blade method, and vacuumed at 150 ° C. for 2 hours. Each negative electrode was dried and formed into a sheet.

Here, in preparing the negative electrode by applying the slurry containing the negative electrode material to the negative electrode current collector as described above,
In these examples, as in the case of the positive electrode, the negative electrode current collector was provided with a portion not coated with the slurry, and the width of the portion not coated with the slurry was negative electrode collector. Similarly, in Example 1, 0.5 mm,
1 mm in Example 2, 2 mm in Example 3, 3 mm in Example 4, 5 mm in Example 5, 8 mm in Example 6,
In Example 7, it was 10 mm, and in Example 8, it was 12 mm.

[Preparation of Non-Aqueous Electrolyte] In preparing the non-aqueous electrolyte, a mixed solvent prepared by mixing ethylene carbonate and dimethyl carbonate in a volume ratio of 1: 1 was added.
Lithium hexafluorophosphate LiPF ₆ was dissolved as a solute at a ratio of 1 mol / l to prepare a non-aqueous electrolytic solution.

[Preparation of Battery] In preparing a secondary battery in these examples, as shown in FIG. 2, lithium was used as the separator 3 between the positive electrode 1 and the negative electrode 2 prepared as described above. A portion of the positive electrode current collector 1a to which the positive electrode material 1b is not attached and a portion of the negative electrode current collector 2a to which the negative electrode material 2b is not attached are reversed with the ion-permeable polypropylene microporous film interposed. Each electrode group was obtained by spirally winding these so as to project in the direction.

The battery can 4a serving as the negative electrode terminal 4a
And a battery lid 4b serving as a positive electrode terminal 4b, and a negative electrode material 2 is formed on the bottom surface of the battery can 4a.
Each of the above electrode groups was housed in each battery can 4a such that the portion of the negative electrode current collector 2a to which b was not attached was brought into contact, and then the above nonaqueous electrolyte solution was placed in each battery can 4a. Then, the battery lid 4b having the insulating packing 7 attached thereto is attached by pushing it into each battery can 4a, and each battery can 4a is sealed by each battery lid 4b. A portion of the positive electrode current collector 1a to which the positive electrode material 1b is not attached is pressure-bonded to the inner surface of the battery, and a portion of the negative electrode current collector 2a to which the negative electrode material 2b is not attached is pressure-bonded to the bottom surface of each battery can 4a. Then, each lithium secondary battery was produced. As described above, the portion of the positive electrode current collector 1a to which the positive electrode material 1b is not attached is pressure-bonded to the inner surface of each battery lid 4b, and the portion of the negative electrode current collector 2a to which the negative electrode material 2b is not attached is removed. When crimping the bottom surface of each battery can 4a, the length of each crimping portion was set to about 1 mm.

(Embodiment 9) In this embodiment, like the secondary battery of Embodiment 4 described above, the width of the portion of the positive electrode current collector 1a made of aluminum foil to which the positive electrode material 1b is not adhered. 3 mm, and the width of the portion of the negative electrode current collector 2a made of copper foil to which the negative electrode material 2b is not attached is set to 3 mm. In this embodiment, as shown in FIG. Battery cover 4 to which is crimped
Battery can 4a to which the inner surface portion of b and the negative electrode current collector 2a are pressure bonded
A stainless steel current collecting net 10 was attached to each of the inner bottom surfaces, and a lithium secondary battery was produced in the same manner as in each of the above-described examples except for the above.

Comparative Example 1 In this comparative example, FIG.
As in the case of the conventional secondary battery shown in FIG. 1, the positive electrode current collecting tab 5 attached to the positive electrode current collector 1 a of the positive electrode 1 is attached to the battery lid 4.
While being welded to the inner surface of b, the negative electrode current collector 2a of the negative electrode 2
The negative electrode current collecting tab 6 attached to was welded to the bottom surface of the battery can 4a, and other than that, the lithium secondary battery was manufactured in the same manner as in each of the above-described examples.

Comparative Example 2 In this Comparative Example, as shown in FIG. 4, for the positive electrode 1, the positive electrode current collector tab 5 attached to the positive electrode current collector 1a is welded to the inner surface of the battery lid 4b. As for the negative electrode 2, the width of the portion of the negative electrode current collector 2a to which the negative electrode material 2b is not adhered is set to 3 mm, as in the case of the fourth embodiment.
Portion of the negative electrode current collector 2a on which the battery is not attached is attached to the battery can 4a.
A lithium secondary battery was manufactured so as to be pressure-bonded to the bottom part of the inside.

(Comparative Example 3) In this comparative example, as shown in FIG. 5, for the negative electrode 2, the negative electrode current collector tab 6 attached to the negative electrode current collector 2a was welded to the bottom surface of the battery can 4a. On the other hand, for the positive electrode 1, as in the case of the fourth embodiment, the width of the portion of the positive electrode current collector 1a where the positive electrode material 1b is not attached is set to 3 mm.
The portion of the positive electrode current collector 1a where b is not attached is attached to the battery lid 4
A lithium secondary battery was manufactured by pressing the inner surface of b.

Next, Example 1 produced as described above
9 to 9 and each of the secondary batteries of Comparative Examples 1 to 3, a temperature of 25
Under the condition of ℃, charging current 1A, end-of-charge voltage 5.2V
After charging up to, discharge current 1A and discharge end voltage 3
The battery was discharged to V, and charging and discharging were repeated by setting this as one cycle, and the number of cycles in which the capacity of each battery was 80% of the initial capacity was determined. The results are shown in Table 1 below.

[0031]

[Table 1]

As a result, the portion of the positive electrode current collector 1a to which the positive electrode material 1b is not attached is pressure-bonded to the inner surface of the battery lid 4b, and the portion of the negative electrode current collector 2a to which the negative electrode material 2b is not attached is attached to the battery can. Each of the secondary batteries of Examples 1 to 9 that was pressure-bonded to the bottom surface portion in 4a was a secondary battery of Comparative Examples 1 to 3 in which both or one of the positive electrode 1 and the negative electrode 2 was not pressure-bonded in this manner. The number of cycles at which the initial capacity is 80% of that of the battery is increased, and stable charging / discharging can be performed for a long period even when charging / discharging is performed at a large current.

In addition, in the secondary batteries of Examples 1 to 9 described above, the widths of the portions where the positive electrode material 1b and the negative electrode material 2b are not attached to the respective current collectors 1a and 2a are set within the range of 1 to 10 mm. 2-7 and Example 9,
The number of cycles reaching 80% of the initial capacity is increasing. Especially, on the inner surface part of the battery lid 4b to which the positive electrode current collector 1a is pressure bonded and the bottom surface part inside the battery can 4a to which the negative electrode current collector 2a is pressure bonded. In the case of Example 9 in which each of the current collecting networks 10 was attached, the number of cycles at which the initial capacity reached 80% increased, and even when charging / discharging was performed at a large current, the cycle was stable for a longer period of time. I was able to charge and discharge.

Example 10 In this example, nickel oxyhydroxide (NiOO) was used as the positive electrode material as follows.
H) is used to manufacture a positive electrode, while a negative electrode is manufactured using an Mm-based hydrogen storage alloy to prepare a negative electrode, and a cylindrical nickel-hydrogen secondary battery having the structure shown in FIG. It was made.

[Preparation of Positive Electrode] To prepare a positive electrode, an aqueous solution containing 1% by weight of methylcellulose is added to nickel oxyhydroxide, which is a positive electrode material, and these are kneaded to form a paste. Apply to both sides of a 0.05 mm thick nickel thin plate that is an electric body,
This was dried and the positive electrode was produced. Incidentally, when the paste containing the positive electrode material is applied to the positive electrode current collector to manufacture the positive electrode as described above, in this embodiment, the positive electrode current collector is provided with a portion where the paste is not applied,
Its width was 3 mm.

[Preparation of Negative Electrode] In preparing the negative electrode, an Mm-based hydrogen storage alloy used as a negative electrode material was prepared.
A hydrogen storage alloy having a composition of MmNi _3.2 Co _1.0 Al _0.2 Mn _0.6 is used, polyethylene oxide and water are added thereto, and these are kneaded to form a paste, and the paste is a negative electrode current collector having a thickness of 0.05 mm. Was applied to both surfaces of the nickel thin plate of No. 1 and dried to prepare a negative electrode. When the paste containing the negative electrode material is applied to the negative electrode current collector as described above to form the negative electrode, the negative electrode current collector is provided with a portion to which the paste is not applied, as in the case of the positive electrode. , Its width was 3 mm.

[Preparation of Battery] Also in preparing the secondary battery of this example, as shown in FIG. 2, a nylon non-woven fabric was formed between the positive electrode 1 and the negative electrode 2 prepared as described above. A portion of the positive electrode current collector 1a where the separator 3 is interposed and the positive electrode material 1b is not attached, and the negative electrode material 2b.
Part of the negative electrode current collector 2a to which is not attached is projected in the opposite direction, and these are spirally wound to obtain an electrode group.

The battery can 4a serving as the negative electrode terminal 4a
And a battery lid 4b serving as a positive electrode terminal 4b, and a negative electrode material 2 is formed on the bottom surface of the battery can 4a.
After the above-mentioned electrode group was housed in the battery can 4a such that the portion of the negative electrode current collector 2a to which b was not attached was brought into contact, a 7M aqueous potassium hydroxide solution was used as an electrolytic solution in the battery can 4a. Then, the battery lid 4b having the insulating packing 7 attached thereto is pushed into the battery can 4a, and the battery can 4a is sealed by the battery lid 4b. While pressing the portion of the positive electrode current collector 1a to which the positive electrode material 1b is not attached,
A portion of the negative electrode current collector 2a to which the negative electrode material 2b was not attached was pressure-bonded to the bottom surface of the battery can 4a to produce a nickel-hydrogen secondary battery. In addition, as described above, the positive electrode material 1b
The portion of the positive electrode current collector 1a not attached to the battery cover 4b
When the portion of the negative electrode current collector 2a to which the negative electrode material 2b is not attached is pressure-bonded to the bottom portion of the battery can 4a while being pressure-bonded to the inner surface of the battery, the length of each pressure-bonded portion is about 1 mm. I did it.

(Comparative Example 4) Also in this Comparative Example, as in Example 10 above, a positive electrode was prepared using nickel oxyhydroxide (NiOOH) as the positive electrode material, and the above Mm was used as the negative electrode material. In this comparative example, the positive electrode attached to the positive electrode current collector 1a of the positive electrode 1 was used in the same manner as in the conventional secondary battery shown in FIG. Connect the current collecting tab 5 to the battery lid 4b
And the negative electrode current collector tab 6 attached to the negative electrode current collector 2a of the negative electrode 2 are welded to the bottom surface of the battery can 4a. Otherwise, the same as in the case of Example 10 above. Then, a nickel-hydrogen secondary battery was produced.

Next, Example 1 produced as described above
0 and the respective secondary batteries of Comparative Example 4 in Example 1 above.
9 to 9 and Comparative Examples 1 to 3, under the condition of a temperature of 25 ° C., after charging to a charge end voltage of 5.2 V with a charge current of 1 A, discharge to a discharge end voltage of 3 V with a discharge current of 1 A. This was set as one cycle, and charging / discharging was repeated to obtain the number of cycles in which the capacity of each battery was 80% of the initial capacity.

As a result, in the secondary battery of Comparative Example 4 produced in the same manner as in the case of the conventional secondary battery shown in FIG. 1, the number of cycles was 1000, while in FIG. As shown, the portion of the positive electrode current collector 1a to which the positive electrode material 1b is not attached is pressure-bonded to the inner surface of the battery lid 4b, and the portion of the negative electrode current collector 2a to which the negative electrode material 2b is not attached is located inside the battery can 4a. In the secondary battery of Example 10 that was pressure-bonded to the bottom surface, the number of cycles was 1200, and the number of cycles that was 80% of the initial capacity increased compared to the secondary battery of Comparative Example 4. Even when charging / discharging with a large current, stable charging / discharging can be performed for a long period of time.

[0042]

As described above in detail, in the secondary battery according to the present invention, the positive electrode current collector has the positive electrode material attached to the positive electrode and the negative electrode current collector has the negative electrode material attached to the negative electrode. In accommodating a multi-layered electrode group in a battery container with a separator interposed between them, a portion where the positive electrode material is not attached to the positive electrode current collector is provided, and this portion is crimped to the positive electrode terminal, and the negative electrode Since the current collector has a part where the negative electrode material is not attached and this part is crimped to the negative electrode terminal, the current flows through these current collectors, and the current flows through the positive electrode current collector tab and the negative electrode current collector. Compared with the case where the current flows through the tab, the area where the current flows becomes much larger.

As a result, in the secondary battery of the present invention, even when the battery capacity is increased and charging / discharging is performed with a large current, a part of the positive electrode or the negative electrode is heated and the positive electrode material is heated. It is possible to obtain a secondary battery with excellent cycle characteristics that can perform stable charge and discharge with a large current, and to prevent a large amount of charge and discharge with a large current. It has become suitable for use in electric vehicles that are carried out.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view showing the internal structure of secondary batteries of a conventional type and comparative examples 1 and 4.

FIG. 2 is a sectional explanatory view showing the internal structure of the secondary batteries of Examples 1 to 8 and Example 10 of the present invention.

FIG. 3 is a sectional explanatory view showing an internal structure of a secondary battery of embodiment 9 of the present invention.

FIG. 4 is a cross-sectional explanatory view showing an internal structure of a secondary battery of Comparative Example 2.

5 is a cross-sectional explanatory view showing the internal structure of the secondary battery of Comparative Example 3. FIG.

[Explanation of symbols]

1 positive electrode 1a Positive electrode current collector 1b Positive electrode material 2 Negative electrode 2a Negative electrode current collector 2b Negative electrode material 3 separator 4 battery container 4a Negative electrode terminal (battery can) 4b Positive electrode terminal (battery lid) 10 electricity collection network

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Nishio 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd. (56) Reference JP-A-2-288158 (JP, A) (58) ) Fields investigated (Int.Cl. ⁷ , DB name) H01M 10/04 H01M 10/40 H01M 6/02 H01M 2/26

Claims (4)

(57) [Claims] 1. A battery comprising a positive electrode current collector having a positive electrode material adhered thereto and a negative electrode current collector having a negative electrode material adhered thereto and a separator interposed between the positive electrode current collector and a negative electrode formed in a multilayer structure. In the secondary battery housed in the container, a portion where the positive electrode material is not attached is provided at the end of the positive electrode current collector to which the positive electrode material is attached, and the negative electrode is attached to the end of the negative electrode current collector to which the negative electrode material is attached. Provide a part where no material is attached, crimp the part of the positive electrode current collector to which the positive electrode material is not attached to the positive electrode terminal, and press the part of the negative electrode current collector to which the negative electrode material is not attached to the negative electrode terminal. A secondary battery characterized by that. 2. The secondary battery according to claim 1, wherein
A secondary battery, wherein the width of the portion of the negative electrode current collector to which the negative electrode material is not attached and the width of the portion of the positive electrode current collector to which the positive electrode material is not attached are each in the range of 1 to 10 mm. 3. The secondary battery according to claim 1, wherein a current collecting network or a conductive paste is provided on at least one of the positive electrode terminal and the negative electrode terminal. 4. The secondary battery according to claim 1, wherein the secondary battery has a battery capacity of 5 Wh or more.