JPH11111262A - Thin battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a cycle characteristic, and provide sufficient battery capacity without thickening a thickness of a thin battery even when lead parts are arranged by forming the lead parts in respective ones by respectively projecting a part of a positive electrode enclosing body and a negative electrode enclosing body outward. SOLUTION: A positive electrode enclosing body 10 and a negative electrode enclosing body 20 are respectively formed of an aluminium conductive plate, and a material where respectively outward projecting lead parts 10a and 20a are formed in its part is used. A separator 30 composed of a polypropylene microporous film impregnated with a nonaqueous electrlyte, is interposed between a positive electrode 11 formed on a positive electrode current collecting body 12 and a negative electrode 21 formed on a negative electrode current collecting body 22, and this is sandwiched between both electrode enclosing bodies 10 and 20, and a sealing material 40 composed of electric insulating modified polypropylene is arranged in a peripheral part with both enclosing bodies 10 and 20, and a part between both enclosing bodies 10 and 20 is sealed by this sealing material 40, and is electrically insulated, and a thin battery is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin battery having a positive electrode, a negative electrode, and an electrolyte provided between an electrically insulated positive electrode package and a negative electrode package. The present invention relates to a thin battery having a lead portion protruding outward from a body or a negative electrode package.

[0002]

2. Description of the Related Art Conventionally, a thin battery has been used as a power source for an IC card, a calculator, and the like. As such a thin battery, as shown in FIGS. 1 and 2, a positive electrode formed of a conductive plate is used. A positive electrode 11 attached to the positive electrode current collector 12, a separator 30 containing an electrolyte, and a negative electrode 21 attached to the negative electrode current collector 22 are provided between the outer package 10 and the negative electrode package 20. A sealing material 40 made of an electrically insulating resin or the like is provided around the positive electrode exterior body 10 and the negative electrode exterior body 20, and between the positive electrode exterior body 10 and the negative electrode exterior body 20 by the sealing material 40. In which the positive electrode package 10 and the negative electrode package 20 are electrically insulated.

In such a thin battery, in order to extract current from the battery, the lead portions 51, which are formed of a conductive plate or the like, are provided on the outer surface portions of the above-mentioned positive electrode casing 10 and negative electrode casing 20. 52 is a positive electrode package 10
And the negative electrode exterior body 20 so as to protrude outward.

However, when the lead portions 51 and 52 are separately attached to the outer surface portions of the positive electrode casing 10 and the negative electrode casing 20 as described above, the thickness of the whole battery is increased by the amount of the leads 51 and 52. There was a problem of becoming.

In recent years, Japanese Patent Application Laid-Open No. 5-325
As shown in Japanese Unexamined Patent Application Publication No. 923, in the above-described thin battery, as shown in FIGS. 3 and 4, a part of the positive electrode current collector 12 and the negative electrode current collector 22 provided in the battery is partially replaced. It has been proposed that each of them protrudes outward of the battery from the sealing material 40 and is used as each of the lead portions 12a and 22a.

Here, as described above, when a part of the positive electrode current collector 12 or the negative electrode current collector 22 is protruded outside the battery and used as the lead portions 12a, 22a, these current collectors 1
Current collectors 12,2 having a thickness of 2,22 generally used
2, the lead portion 12 protruded in this manner.
Since there is a possibility that the current collectors a and 22a may be easily cut, it is necessary to increase the thickness of the current collectors 12 and 22.

However, when the thicknesses of the positive electrode current collector 12 and the negative electrode current collector 22 are increased in this manner, similar to the above case,
There is a problem that the thickness of the entire battery in the thin battery is increased.

In each of the above thin batteries,
If the thickness of the positive electrode package 10 and the negative package 20 is reduced in order to reduce the thickness, the strength of these thin batteries is reduced, and when the battery is charged and discharged, the thin batteries are deformed and cycled. There is a problem that the characteristics are deteriorated, and when the thickness of the positive electrode 11 or the negative electrode 12 provided in the thin battery is reduced, there is a problem that a sufficient battery capacity cannot be obtained.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a thin battery having a positive electrode, a negative electrode, and an electrolyte provided between an electrically insulated positive electrode package and a negative electrode package. It is an object of the present invention to solve the above-described problem in the case of providing a lead portion protruding outward from the exterior body, and in the case of providing a lead portion,
It is an object of the present invention to provide a thin battery having excellent cycle characteristics and a sufficient battery capacity without increasing the thickness of the thin battery unlike the related art.

[0010]

In the thin battery according to the first aspect of the present invention, in order to solve the above-mentioned problems, the positive and negative electrode casings made of a conductive plate are electrically insulated. In addition, in a thin battery in which a positive electrode, a negative electrode, and an electrolyte are provided between the positive electrode package and the negative electrode package, a part of the positive electrode package and a part of the negative electrode package are projected outward. A lead portion was formed for each.

[0011] Here, as in the thin battery according to the first aspect, when a part of the positive electrode casing and the part of the negative electrode casing are projected outward to form leads, respectively, the positive electrode casing and the negative electrode casing are formed. When attaching a lead made of a separate conductive plate to the body or increasing the thickness of the positive electrode current collector and the negative electrode current collector, projecting a part of these current collectors to the outside of the battery The thickness of the thin battery can be reduced as compared with the case where no thin film is provided, and there is no need to reduce the thickness of the positive electrode casing and the negative electrode casing, and the thickness of the positive electrode and the negative electrode. Thus, a thin battery having a sufficient battery capacity can be obtained.

Here, if the thickness of the conductive plate constituting the above-mentioned positive electrode casing and negative electrode casing is small, the strength of the thin battery becomes weak, and when the battery is charged and discharged, the thin battery is deformed. On the other hand, when the thickness is too large while the cycle characteristics are deteriorated, the thickness of the thin battery is increased. Therefore, the thickness of the conductive plate is preferably in the range of 15 μm to 150 μm.

It is preferable to use a material that is chemically stable and does not deteriorate by reacting with an electrolyte or the like in a battery, for example, aluminum, aluminum, or the like. It is preferable to use a conductive plate made of nickel or stainless steel.

Further, as in the thin battery according to the third aspect of the present invention, at least on each of the surfaces of the above-mentioned positive and negative electrode casings facing each other, a connection portion with the positive electrode or the negative electrode is left, and the electrical insulation is provided. When a resin layer made of a conductive resin is formed,
By positively and positively insulating the positive electrode casing and the negative electrode casing by the electrically insulating resin, such a resin layer adheres well to a sealing material sealing the periphery of the thin battery, Ingress and egress of moisture and the like in the sealed portion are also suppressed, and the cycle characteristics and the like in the thin battery are improved.

Here, when forming a resin layer made of an electrically insulating resin on each of the surfaces where the positive electrode casing and the negative electrode casing oppose each other, if the thickness of the resin layer is small, the thickness of the thin battery is reduced. Adhesion with the sealing material that seals the periphery is not performed well, and it is not possible to sufficiently suppress the entry and exit of moisture and the like at the sealing portion.On the other hand, when the thickness of this resin layer is too thick, the thickness of the thin battery increases It is preferable that the thickness of the resin layer be in the range of 15 μm to 150 μm because it is too much.

As the resin constituting the resin layer, it is preferable to use a resin which is appropriately adhered to a sealing material for sealing the periphery of the thin battery and which can sufficiently suppress the entry and exit of moisture and the like at the sealing portion. For example, it is preferable to use polypropylene or polyethylene.

The thin battery according to the present invention may have any of the above-described structures, and its positive electrode, negative electrode and electrolyte are not particularly limited, and are generally used in lithium batteries and alkaline batteries. Various materials can be used. As the electrolyte, a solid electrolyte having lithium ion conductivity typified by polyethylene oxide or the like can be used other than the case where the liquid shown in this embodiment is used.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a thin battery according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings, and a comparative example will be described. In the thin battery according to the embodiment of the present invention, the thickness is reduced. And that the cycle characteristics are improved. The thin battery according to the present invention is not limited to those described in the following examples, but can be implemented by appropriately changing the scope of the invention without changing its gist.

(Example 1) In this example, a positive electrode, a negative electrode and a non-aqueous electrolyte prepared as described below were used, and the height was 9 cm and the width was 5 cm as shown in FIGS. A thin battery was manufactured.

[Preparation of Positive Electrode] In preparing the positive electrode, lithium cobaltate LiCoO ₂ was used as a positive electrode material. LiCoO ₂ , artificial graphite as a conductive agent, and polyvinylidene fluoride as a binder were used. 80:10:10
, And N-methyl-2-pyrrolidone was added thereto to form a slurry. Then, this slurry was mixed with a positive electrode current collector 12 made of aluminum foil having a thickness of 20 μm.
Is coated on one surface of the positive electrode current collector 12 by a doctor blade method, and then dried in a vacuum at 150 ° C. for 2 hours to form a positive electrode 11 having a thickness of 80 μm on the positive electrode current collector 12.
Was formed.

[Preparation of Negative Electrode] In preparing the negative electrode, as a negative electrode material, a lattice distance d002 of the lattice plane (002) was used.
Is 3.35 °, and the crystallite size Lc in the c-axis direction is 10
Using a carbon powder of 00 ° or more, this carbon powder and polyvinylidene fluoride as a binder were mixed at a weight ratio of 90:10, and N-methyl-2-pyrrolidone was added thereto to form a slurry. Then, this slurry is coated with a thickness of 20μ.
m of a negative electrode current collector 22 made of copper foil by a doctor blade method.
After drying at 50 ° C. for 2 hours, a negative electrode 21 having a thickness of 80 μm was formed on the negative electrode current collector 22.

[Preparation of Non-Aqueous Electrolyte] In preparing a non-aqueous electrolyte, a mixed solvent obtained by mixing ethylene carbonate and diethyl carbonate at a volume ratio of 1: 1 was used.
LiPF ₆ was dissolved at a rate of 1 mol / l to prepare a non-aqueous electrolyte.

[Preparation of Battery] In preparing a battery, as shown in FIGS. 5 and 6, a positive electrode outer casing 10 and a negative electrode outer casing 20 were each made of an aluminum conductive plate having a thickness of 100 μm. In this case, the lead portions 10a and 20a protruding outward are formed on a part thereof.

The nonaqueous electrolyte was impregnated between the positive electrode 11 formed on the positive electrode current collector 12 and the negative electrode 21 formed on the negative electrode current collector 22 as described above. A separator 30 having a thickness of 40 μm, made of a polypropylene microporous film, is interposed therebetween, and is sandwiched between the above-mentioned positive electrode package 10 and the negative electrode package 20. A sealing material 40 made of an electrically insulating modified polypropylene is provided in a peripheral portion of the outer package 20, and the sealing material 40 seals the gap between the positive electrode package 10 and the negative electrode package 20. A thin battery was manufactured by electrically insulating the negative electrode package 20 from the negative electrode package 20. The thickness of the entire thin battery was 0.44 mm as shown in Table 1 below.

(Comparative Example 1) In the thin battery of Comparative Example 1, as in the thin battery of Example 1 described above, the lead portions 10a, 10a,
As shown in FIGS. 1 and 2 described above, the outer surface portions of the positive electrode casing 10 and the negative electrode casing 20 were formed of an aluminum conductive plate having a thickness of 100 μm without forming the 20a. The lead portions 51 and 52 are respectively connected to the positive
A negative battery was manufactured in the same manner as in Example 1 except that the battery was attached so as to protrude outward from the negative electrode package 20. The thickness of the entire thin battery was 0.64 mm as shown in Table 1 below.

(Comparative Example 2) In the thin battery of Comparative Example 2, as in the thin battery of Example 1, lead portions 10a, 10a,
20a, the thickness of each of the positive electrode current collector 12 and the negative electrode current collector 22 was set to 100 μm, and FIG.
As shown in FIG. 4, a part of the positive electrode current collector 12 and a part of the negative electrode current collector 22 are respectively protruded outward of the battery from the sealing material 40 to provide the respective lead portions 12a and 22a. Except for the above, a thin battery was manufactured in the same manner as in Example 1 above. The overall thickness of the thin battery was 0.60 mm as shown in Table 1 below.

(Example 2) In the thin battery of Example 2, as shown in FIG. 7, the surface of the thin battery of Example 1 is different from that of the thin battery of Example 1 in that the cathode 10 and the anode 20 face each other. The positive electrode current collector 12 or the negative electrode current collector 2
Except for the connection parts 14 and 24 with the second resin layer 2, resin layers 13 and 23 made of an electrically insulating polypropylene resin having a film thickness of 100 μm are provided, and otherwise the same as in the case of the first embodiment. Thus, a thin battery in which lead portions 10a and 20a protruding outward were formed on a part of the positive electrode casing 10 and the negative electrode casing 20 was produced. The thickness of the entire thin battery was 0.64 mm as shown in Table 1 below.

(Comparative Example 3) In the thin battery of Comparative Example 3, in the thin battery of Comparative Example 1 described above, the respective surfaces of the positive and negative electrode cases 10 and 20 facing each other are
As in the case of the second embodiment, a resin made of an electrically insulating polypropylene resin having a thickness of 100 μm, except for the connection portions 14 and 24 connected to the positive electrode current collector 12 and the negative electrode current collector 22. A thin battery was manufactured in the same manner as in Comparative Example 1 except that layers 13 and 23 were provided. The thickness of the entire thin battery was 0.84 mm as shown in Table 1 below.

Comparative Example 4 The thin battery of Comparative Example 4 is different from the thin battery of Comparative Example 2 described above in that the respective surfaces of the positive and negative electrode cases 10 and 20 facing each other are:
As in the case of the second embodiment, a resin made of an electrically insulating polypropylene resin having a thickness of 100 μm, except for the connection portions 14 and 24 connected to the positive electrode current collector 12 and the negative electrode current collector 22. A thin battery was manufactured in the same manner as in Comparative Example 2 except that layers 13 and 23 were provided. The overall thickness of the thin battery was 0.80 mm as shown in Table 1 below.

Next, each of the thin batteries of Examples 1 and 2 and Comparative Examples 1 to 4 manufactured as described above was
After charging to 4.1 V with a constant current of A, 50 mA
The discharge is performed up to 2.8 V at a constant current of 1. The charge / discharge is repeated 200 times with this as one cycle, the discharge capacity Q1 in the first cycle and the discharge capacity Q200 in the 200th cycle are measured, and based on the following equation: The rate of deterioration of the discharge capacity per cycle (cycle deterioration rate) was determined, and the results are shown in Table 1 below. Cycle deterioration rate (% / cycle) = (Q1-Q200) x
100 / Q1 × 200

[0031]

[Table 1]

As is clear from the results, the thin batteries of Examples 1 and 2 in which the outwardly protruding leads 10a and 20a are formed on a part of the positive electrode casing 10 and the negative electrode casing 20, respectively. The battery thickness was smaller than the corresponding thin batteries of Comparative Examples 1 and 2, and the thin batteries of Comparative Examples 3 and 4.

Further, the thin battery of Example 1 in which the resin layers 13 and 23 were not provided on the respective surfaces of the cathode package 10 and the anode package 20 facing each other, and Example 2 in which the resin layers 13 and 23 were provided. Compared with a thin battery, the thickness of the battery is thinner in the thin battery of Example 1 in which the resin layers 13 and 23 are not provided, but in the thin battery of Example 2 in which the resin layers 13 and 23 are provided, The cycle deterioration rate was lower than that of the thin battery of Example 1, and the cycle characteristics were improved.

(Examples 3 to 5) In the thin batteries of Examples 3 to 5, the materials constituting the conductive plates used for the positive and negative electrode casings 10 and 20 are different from those of the thin battery of Example 2 described above. Was changed as shown in Table 2 below, and nickel was used in Example 3 and SUS304 was used in Example 4.
Stainless steel. In Example 5, the thickness of iron is 100.
Each thin battery was manufactured in the same manner as in Example 2 except that a μm conductive plate was used. In addition,
The overall thickness of these thin batteries was 0.64 mm as shown in Table 2 below.

For each of the thin batteries of Examples 3 to 5, the cycle deterioration rate was determined in the same manner as described above, and the results were combined with those of the thin battery of Example 2 in the following table. 2 is shown.

[0036]

[Table 2]

As is apparent from the results, Examples 2 to 4 in which a conductive plate made of aluminum, nickel, and SUS304 stainless steel were used as the conductive plates constituting the cathode casing 10 and the anode casing 20 were used. Each of the thin batteries had a lower cycle deterioration rate and improved cycle characteristics as compared with the thin battery of Example 5 using the conductive plate made of iron.

(Examples 6 and 7) In the thin batteries of Examples 6 and 7, the thickness of the conductive plate of aluminum used for the positive electrode casing 10 and the negative electrode casing 20 is different from that of the thin battery of Example 2 described above. Was changed as shown in Table 3 below. In Example 6, the thickness was changed to 10 μm.
Then, the thickness is set to 200 μm.
Each thin battery was manufactured in the same manner as in Example 2 described above. The overall thickness of these thin batteries was as shown in Table 3 below.

For each of the thin batteries of Examples 6 and 7, the cycle deterioration rate was determined in the same manner as described above, and the results were combined with the thin batteries of Example 2 to obtain the following table. 3 is shown.

[0040]

[Table 3]

As a result, the thickness of the aluminum conductive plate constituting the positive electrode package 10 and the negative electrode package 20 was reduced to 10 μm.
In the case of the thin battery of Example 6 having a thickness of
Although the thickness of the battery was smaller than that of the thin battery, the value of the cycle deterioration rate was greatly increased, and the cycle characteristics were greatly reduced. On the other hand, in the case of the thin battery of Example 7 in which the thickness of the conductive plate was increased to 200 μm, the cycle deterioration rate was slightly lower and the cycle characteristics were improved as compared with the thin battery of Example 2. The thickness of the battery was increasing.

(Embodiments 8 and 9) In the thin batteries of Embodiments 8 and 9, the resin provided on each of the surfaces of the thin battery of Embodiment 2 where the positive and negative electrode casings 10 and 20 face each other. Only the materials of the layers 13 and 23 were changed as shown in Table 4 below. In Example 8, polyvinyl chloride was used, and in Example 9, polybutylene was used. The other thin batteries were manufactured in the same manner as in Example 2 except for the above. In addition, as shown in Table 4 below, the overall thickness of these thin batteries was 0.64 m.
m.

For each of the thin batteries of Examples 8 and 9, the cycle deterioration rate was obtained in the same manner as described above, and the results were combined with the thin batteries of Example 2 above. The results are shown in FIG.

[0044]

[Table 4]

As a result, the cathode casing 10 and the anode casing 2
Resin layers 13 and 23 provided on respective surfaces facing 0
When using polypropylene as the material, the value of the cycle deterioration rate is the lowest and the cycle characteristics are improved,
Then, the order was polybutylene and polyvinyl chloride. This is because, when polypropylene is used as the resin constituting the resin layers 13 and 23, the sealing material 40 for sealing the periphery of the thin battery and the resin layers 13 and 2 are used.
It is considered that the reason for this is that the adhesive layer 3 was appropriately adhered, and the entry and exit of moisture and the like at the sealing portion could be sufficiently suppressed.

(Examples 10 and 11) In the thin batteries of Examples 10 and 11, in the thin battery of Example 2 described above, the surfaces of the cathode outer casing 10 and the anode casing 20 facing each other were made of polypropylene. Resin layer 13,
When the resin layer 23 is provided, only the thickness of the resin layers 13 and 23 is set to 10 μm in Example 10 as shown in Table 5 below.
m, and in Example 11, the thickness was changed to 200 μm, and other than that, each thin battery was manufactured in the same manner as in Example 2 above. The overall thickness of these thin batteries was as shown in Table 5 below.

For each of the thin batteries of Examples 10 and 11, the cycle deterioration rate was obtained in the same manner as described above, and the results were combined with the thin batteries of Example 2 to obtain the following table. 5 is shown.

[0048]

[Table 5]

As a result, the cathode casing 10 and the anode casing 2
Resin layers 13 and 23 provided on respective surfaces facing 0
In the case of the thin battery of Example 10 in which the thickness of the battery was reduced to 10 μm, the thickness of the battery was smaller than that of the thin battery of Example 2, but the value of the cycle deterioration rate was increased, and the cycle characteristics were poor. It had dropped considerably. On the other hand, in the case of the thin battery of Example 11 in which the thickness of the resin layers 13 and 23 was increased to 200 μm, the cycle deterioration rate was slightly lower than that of the thin battery of Example 2, and the cycle characteristics were improved. However, the thickness of the battery was increased.

[0050]

As described in detail above, in the thin battery according to the present invention, a part of the positive electrode casing and a part of the negative electrode casing are projected outward to form respective lead portions. When attaching a lead made of a separate conductive plate to the outer package or negative electrode package, or by increasing the thickness of the positive electrode current collector or negative electrode current collector, remove some of these current collectors from the outside of the battery. The thickness of the thin battery can be reduced as compared with the case where the lead portion is provided by protruding the battery.

For this reason, in the thin battery of the present invention, it is not necessary to reduce the thickness of the positive electrode package, the negative electrode package, the positive electrode and the negative electrode in order to reduce the thickness. A thin battery having excellent characteristics and sufficient battery capacity was obtained.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a conventional thin battery in which leads are separately provided on outer surface portions of a positive electrode casing and a negative electrode casing.

FIG. 2 is a schematic cross-sectional view of the conventional thin battery shown in FIG.

FIG. 3 is a schematic perspective view of a conventional thin battery in which a positive electrode current collector and a part of a negative electrode current collector protrude outward from the battery to provide a lead portion.

FIG. 4 is a schematic cross-sectional view of the conventional thin battery shown in FIG.

FIG. 5 is a schematic perspective view of a thin battery according to Embodiment 1 of the present invention.

FIG. 6 is a schematic sectional view of the thin battery in Example 1 described above.

FIG. 7 is a schematic sectional view of a thin battery according to Embodiment 2 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Positive electrode exterior body 20 Negative electrode exterior body 10a, 20a Lead part 11 Positive electrode 21 Negative electrode

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahisa Fujimoto 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 Koji Nishio 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (4)

[Claims] 1. A cathode package comprising a conductive plate and a cathode package are electrically insulated from each other, and a cathode, an anode and an electrolyte are provided between the cathode package and the anode package. In the thin battery, a part of the above-mentioned positive electrode package and a part of the negative electrode package are respectively protruded outwardly, and a lead portion is formed on each of them. 2. The thin battery according to claim 1, wherein
A thin battery, wherein the thickness of the conductive plates constituting the above-mentioned positive electrode package and negative electrode package is in the range of 15 μm to 150 μm. 3. The thin battery according to claim 1, wherein at least a surface of the positive electrode casing and the negative electrode casing facing each other have a connection portion between the positive electrode and the negative electrode. A thin battery comprising a resin layer formed of a resin. 4. The thin battery according to claim 3, wherein
A thin battery, wherein the thickness of the resin layer is in a range of 15 μm to 150 μm.