JPH11307107A - Organic electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electrolyte battery that can eliminate the winding displacement and the like of a sheet-like positive electrode and a sheet-like negative electrode, can also reduce the defect rate in its manufacturing process and has high safety and reliability. SOLUTION: This is an organic electrolyte battery provided with: an exterior can body 1 which also serves as a negative terminal and of which one end is opened; a spiral electrode group 2 which is installed in the exterior can body 1 and of which negative electrode side is electrically connected to it; an organic electrolytic solution which is infiltrated into and retained by the spiral electrode group 2 and is prepared by solving a lithium salt; and a sealing member 3 which is electrically connected to the positive electrode side of the spiral electrode group 2, insulates and seals 10 the opening of the exterior can body 1, and also serves as a positive terminal. In this case, the spiral electrode group 2 has a structure which is composed by layering and winding a sheet-like positive electrode 4 containing a positive electrode active material, a sheet-like negative electrode 5 which has a width smaller than that of the sheet-like positive electrode 4 and is formed from an alkaline metal or an alkaline metal alloy, and a sheet-like separator 6' which is interposed and arranged between both the sheet-like electrodes 4, 5, and in which structure the separator 6' is interposed and arranged along both the surfaces by being so bent at its one widthwise end surface as to each the sheet-like positive electrode 4 in it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electrolyte battery, and more particularly to a lithium battery having a spiral electrode group in which a sheet-like positive electrode and a negative electrode are wound with a separator interposed therebetween.

[0002]

2. Description of the Related Art A positive electrode using manganese dioxide as an active material;
BACKGROUND ART An organic electrolyte battery having a negative electrode using lithium or a lithium alloy as an active material has a high energy density, and thus has already been put to practical use as a power source for many electronic devices.

FIG. 6 is a longitudinal sectional view showing an example of a configuration of a main part of a conventional organic electrolyte battery. In FIG. 6, 1 is a bottomed cylindrical stainless steel outer can also serving as a cathode terminal, 2 is a spiral electrode group, 3 is a positive electrode terminal which is insulated from the outer can 1 and which is sealed by caulking at an open end. It is a sealing body that forms. Here, the spiral electrode group 2 employs a configuration in which a separator 6 is inserted between the sheet-shaped positive electrode 4 and the sheet-shaped negative electrode 5 and wound.

The sheet-shaped positive electrode 4 is prepared by kneading manganese dioxide (a positive electrode active material) with a graphite powder (a conductive agent) and an aqueous PTFE dispersion (a binder) and applying the mixture to a stainless expanded metal. After drying, rolling, punching into a predetermined shape by a press, and drying again, the configuration shown in a plan view in FIG. 2 is obtained. In FIG. 2, reference numeral 4a denotes a current collecting terminal, and 4b denotes a positive electrode lead electrically connected to the current collecting terminal 4a.

On the other hand, the sheet-shaped negative electrode 5 is obtained by cutting a lithium aluminum alloy foil (negative electrode active material) 5a smaller than the width of the sheet-shaped positive electrode 4. And part of that,
FIG. 3 is a plan view in which a part of the negative electrode current collector 5b (L-shaped piece made of a nickel-plated steel plate) in contact with the bottom inner wall surface of the outer can 1 is pressure-bonded. .

Further, reference numeral 7a denotes an insulating plate interposed between the bottom inner wall surface of the outer can 1 including the negative electrode current collector 5b and the end face of the spiral electrode group 2, and 7b denotes another member of the spiral electrode group 2. An insulating pressing plate 8a mounted on the end face of the safety valve 8a is a safety valve membrane that works in response to an increase in the internal pressure of the battery, and its peripheral edge is fixedly supported by a support 8b. Further, 9 is a thermosensitive element for electrically connecting the positive electrode lead 4b and the positive electrode terminal 3, while controlling conduction in response to a rise in battery temperature, and 10 is a positive electrode for caulking and sealing at the open end of the outer can 1. It is electrically insulated from terminal 3 etc.
It is an insulating seal ring that contributes to hermetic sealing.

[0007] This type of organic electrolyte battery is mainly used for cameras and the like, but its performance has been further improved with the multifunctionality of electronic devices. In addition, an organic electrolyte battery may cause a fire accident depending on a use method and a handling method, and therefore, development of a safer battery is required.

Although there are various causes of the above-mentioned ignition accident, a typical example thereof is a misalignment of the spiral electrode group. Here, the winding misalignment of the electrode group refers to the positioning of the sheet-shaped positive electrode itself or both of the sheet-shaped positive electrode and the sheet-shaped negative electrode when the sheet-shaped positive electrode and the sheet-shaped negative electrode face each other via the separator in the winding step. This indicates that the sheet-shaped positive electrode and the sheet-shaped negative electrode are wound in a state of contact or a state immediately before contact. In addition, although the separator is interposed between the two sheet-shaped electrodes, burrs generated by press punching of the sheet-shaped positive electrode may penetrate the separator, reach the opposed sheet-shaped negative electrode, and cause an internal short circuit. There is.

[0009]

In order to prevent the occurrence of the internal short circuit, the width of the sheet-shaped negative electrode is made smaller than the width of the sheet-shaped positive electrode, and the sheet-shaped negative electrode is provided at the edge of the sheet-shaped positive electrode with a separator interposed therebetween. Attempts have been made to avoid overlapping. Also, regarding the length of the sheet-like electrode and the separator to be wound (wound), in consideration of the case where the spirally wound electrode group is formed, dimensions and setting are performed so that the edges of the sheet-like positive electrode do not overlap, Further, one end of the sheet-shaped negative electrode is fixed with a polypropylene adhesive tape or the like so as not to displace.

On the other hand, when the spirally distorted spiral electrode group is mounted in the outer can, the width end of the sheet-like positive electrode protrudes beyond the separator width and contacts the outer can serving also as the negative electrode terminal to cause a short circuit. The width of the separator is made wider than the width of the sheet-shaped positive electrode so as not to cause a rise, and a donut-shaped polypropylene insulating sheet is placed one by one on both end flat portions (upper and lower) of the spiral electrode group.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic electrolyte battery in which the winding deviation between the sheet-shaped positive electrode and the sheet-shaped negative electrode is eliminated, the defective rate in the manufacturing process can be reduced, and the safety and reliability are high.

[0012]

According to the first aspect of the present invention, there is provided an outer can body having one end opening also serving as a negative electrode terminal, and a spiral electrode mounted in the outer can body with the negative electrode side electrically connected thereto. A group, an organic electrolytic solution in which a lithium salt impregnated and supported by the spiral electrode group is dissolved, and an electrical connection to the positive electrode side of the spiral electrode group, and insulatingly seal the opening of the outer can body. An organic electrolyte battery having a sealing body also serving as a positive electrode terminal, wherein the spiral electrode group comprises a sheet-shaped positive electrode containing a positive electrode active material, and an alkali metal narrower than the sheet-shaped positive electrode. Or alkali metal alloy sheet negative electrode,
And a sheet-like separator interposed between the two sheet-like electrodes to form a laminated wound structure, and the separator is bent at one width end face along the both sides so as to sandwich the sheet-like positive electrode. An organic electrolyte battery, which is interposed and arranged.

According to a second aspect of the present invention, in the organic electrolyte battery according to the first aspect, one end of the sheet-shaped negative electrode of the spiral electrode group is fixed with an adhesive tape.

That is, the invention of claims 1 and 2 assumes that one width end of the sheet-shaped positive electrode is inserted and positioned in a bent portion (valley) of a wide sheet-shaped separator, and the separator is formed. The width of the center of the sheet is set to be wide enough to be able to be prayed. The main point is that a spiral electrode group formed by inserting and winding a folded sheet-shaped positive electrode into two is provided. In the invention of claims 1 and 2, the sheet-like separator is
For example, such as a microporous film made of poly (propylene) resin, has a property of absorbing and supporting the electrolytic solution,
The width is set so as to protrude at least from the sheet-shaped positive electrode width end face.

According to a third aspect of the present invention, there is provided an outer can body having one end opening also serving as a negative electrode terminal, a spiral electrode group mounted in the outer can body by electrically connecting a negative electrode to the outer can body, and An organic electrolytic solution in which a lithium salt impregnated and supported by the electrode group is dissolved, and a closure that is electrically connected to the positive electrode side of the spiral electrode group and also functions as a positive terminal for insulatingly sealing the opening of the outer can body. Wherein the spiral electrode group comprises a sheet-shaped positive electrode containing a positive electrode active material, an alkali metal or alkali metal alloy-based sheet-shaped negative electrode, and a sheet-shaped negative electrode between the sheet-shaped electrode plates. The separator is folded into three so as to sandwich the sheet-shaped positive electrode and the sheet-shaped negative electrode separately, and the sheet-shaped separator is positioned at each valley and is positioned along both sides. Let me An organic electrolyte battery characterized in that it is inserted arranged.

According to a fourth aspect of the present invention, in the organic electrolyte battery according to the third aspect, the thickness of the sheet-like separator of the spiral electrode group is 20 to 25 μm.

That is, the inventions of claims 3 and 4 assume that one width end of each of the sheet-shaped positive electrode and the sheet-shaped negative electrode is inserted into the valley of the three-folded portion for positioning.
The separator should be wide enough to allow three prayers with a line that divides the separator roughly in the width direction, and positioned and fixed so that the sheet-shaped negative electrode does not overlap the edge of the inserted and positioned sheet-shaped positive electrode. The main point is that a spiral electrode group is provided.

In the invention according to claims 3 and 4, the sheet-like separator has a property of absorbing and supporting an electrolytic solution, such as a microporous film made of polypropylene resin, and has a width of at least a sheet-like positive electrode. Must exceed three times the width. That is, when the sheet is folded in three in the width direction, the width is set to be at least so as to protrude from the sheet-shaped positive electrode end face. The thickness of the sheet separator is preferably about 20 to 25 μm.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to FIGS.

Embodiment 1 FIG. 1 is a cross-sectional view showing a main structure of an organic electrolyte battery according to a first embodiment.

In FIG. 1, reference numeral 1 denotes a bottomed cylindrical stainless steel outer can also serving as a cathode terminal, 2 denotes a spiral electrode group,
Reference numeral 3 denotes a sealing body that forms a positive electrode terminal that is insulated from the outer can 1 and that is caulked at the open end. Here, the spiral electrode group 2 has a configuration in which a separator 6 is inserted between the sheet-shaped positive electrode 4 and the sheet-shaped negative electrode 5 and wound, and the spiral electrode group 2 includes, for example, propylene. An organic electrolyte obtained by dissolving lithium lithium trifluorosulfonate in a mixed solvent of carbonate and 1,2-diethoxyethane is impregnated and supported.

The sheet-shaped positive electrode 4 is prepared by kneading manganese dioxide (a positive electrode active material) with a graphite powder (a conductive agent) and a PTFE aqueous dispersion (a binder) and applying the mixture to a stainless expanded metal. After drying, rolling, punching into a predetermined shape by a press, and drying again, the configuration shown in a plan view in FIG. 2 is obtained. In FIG. 2, reference numeral 4a denotes a current collecting terminal, and 4b denotes a positive electrode lead electrically connected to the current collecting terminal 4a.

On the other hand, the sheet-shaped negative electrode 5 is obtained by cutting a lithium aluminum alloy foil (negative electrode active material) 5a smaller than the width of the sheet-shaped positive electrode 4. And part of that,
FIG. 3 is a plan view in which a part of the negative electrode current collector 5b (L-shaped piece made of a nickel-plated steel plate) in contact with the bottom inner wall surface of the outer can 1 is pressure-bonded. .

Reference numeral 7b denotes an insulating pressing plate mounted on the other end face of the spiral electrode group 2, and reference numeral 8a denotes a safety valve film which works in response to an increase in the internal pressure of the battery. Is fixedly supported. Further, 9 is a thermosensitive element for electrically connecting the positive electrode lead 4b and the positive electrode terminal 3, while controlling conduction in response to a rise in battery temperature, and 10 is a positive electrode for caulking and sealing at the open end of the outer can 1. An insulating seal ring that is electrically insulated from the terminal 3 and the like and contributes to hermetic sealing.

Although the configuration described above is basically the same as that of the conventional organic electrolyte battery, the configuration according to the present invention is characterized by the following points. That is, the spiral electrode group 2 includes a sheet-shaped positive electrode 4 containing a positive electrode active material, a sheet-shaped negative electrode 5 of an alkali metal or alkali metal alloy system, and a separator 6 interposed between the two sheet-shaped electrode plates. ′ (For example, a microporous polypropylene film).
As shown in FIG. 4 in a perspective view, the separator 6 'is bent at one width end face so as to sandwich the sheet-like positive electrode 4, and the separator 6' is interposed along both sides. .

That is, the sheet-like positive electrode 4, the sheet-like negative electrode 5, and the microporous film (separator) 6 'made of polypropylene have a separator 6' having a width sufficiently larger than twice the width of the sheet-like positive electrode 4. The sheet-shaped positive electrode 4 is bent and bent from the center line of the width portion, and a sheet-shaped negative electrode 6 'narrower than the width of the sheet-shaped positive electrode 4 is positioned and arranged on one side of the folded back surface, and fixed with a polypropylene adhesive tape. . On the other hand, a sheet-like positive electrode 4 is inserted into the bent valley portion 6a 'to produce an electrode laminate, which is spirally wound.

In the above configuration, the end of the negative electrode current collector 5b protruding from the lower surface of the spiral electrode group 2 is bent along the end surface of the electrode group 2 to form the inner bottom of the outer can 1 also serving as the negative electrode terminal. Resistance welding is performed on the wall.

Comparative Example 1 An organic electrolyte battery having the same structure as in Example 1 except that the width of the sheet-shaped negative electrode 5 was set to be the same as the width of the sheet-shaped positive electrode plate 4 was manufactured.

Comparative Example 2 In the case of Example 1, between the sheet-like positive electrode 4 and the sheet-like negative electrode 5, a separator slightly wider than the width of these two electrode sheets 4, 5 was inserted and fixed to form a spiral. Aside from installing and mounting the wound electrode group 2, an insulating plate 7 a is arranged on the inner bottom wall side of the outer can 1 also serving as a negative electrode terminal,
An organic electrolyte battery (see FIG. 6) having the same configuration was manufactured.

Table 1 shows the results of investigating the defect rate of winding misalignment in the electrode group 2 and the open circuit voltage pass rate in the battery for each of the 100 organic electrolyte batteries according to Example 1 and Comparative Examples 1 and 2. Shown in

[0031] As can be seen from the results in Table 1, in the case of Example 1, no winding deviation failure was recognized, and no open circuit voltage failure occurred. Inconvenience is recognized.

Example 2 In the structure of the organic electrolyte battery according to Example 1, except that the structure of the spiral electrode group 2 was changed as follows.
An organic electrolyte battery having a similar configuration was manufactured. That is, the spiral electrode group 2 includes a sheet-like positive electrode 4 containing a positive electrode active material, an alkali metal or alkali metal alloy sheet negative electrode 5, and a thickness interposed between the two sheet electrode plates. The separator 6 ″ having a thickness of 25 μm (for example, a microporous film made of polypropylene) is laminated and wound, and the widthwise end faces of the sheet-shaped positive electrode 4 and the sheet-shaped negative electrode 5 are sandwiched separately. Then, the separator 6 "is bent into three, the width end faces are aligned with the valleys 6a" and 6b "of the bending, and the separator 6" is interposed and arranged along both surfaces.

More specifically, as shown in perspective in FIG. 5, the sheet-shaped positive electrode 4, the sheet-shaped negative electrode 5, and a polypropylene microporous film (separator)
The width of the separator 6 ″ is set to be sufficiently larger than three times the width of the sheet-shaped positive electrode 4 and is bent into three at approximately three equal lines of the width. Then, one width end face of the sheet-shaped positive electrode 4 is positioned in one of the valleys 6a "and 6b" of the three-folded valleys 6a "and 6b", and the other valley is formed.
6b ", one width end face of the sheet-shaped negative electrode 5 narrower than the sheet-shaped positive electrode 4 is positioned and arranged.
In this stacked state, the electrode group 2 is spirally wound.
Is formed, the width end faces of the spirally wound sheet-shaped positive electrode 4 and sheet-shaped negative electrode 5 are separated by a separator.
6 "are insulated from each other by the bent valleys 6a" and 6b ".
The burr and the like are also completely shut off from the sheet-shaped negative electrode 5 side.

Example 3 In Example 2, the thickness of the separator 6 ″ was set to 20 μm.
An organic electrolyte battery was produced under the same conditions except for the above.

Comparative Example 3 In the case of Example 2 described above, the width of the sheet
The width of the sheet-shaped negative electrode 5 is set to be the same as that of the sheet-shaped negative electrode 5, and a separator 6 slightly wider than the width of the sheet-shaped electrodes 4, 5 is inserted and fixed, and a spirally wound electrode group 2 is incorporated and mounted. An organic electrolyte battery (see FIG. 6) having the same configuration except that an insulating plate 7a was disposed on the inner bottom wall side of the outer can 1 also serving as a negative electrode terminal was produced.

Comparative Example 4 In the case of Example 2 described above, the width of the sheet
An electrode group 2 which is set to have the same width as the sheet-shaped negative electrode 5 and is spirally wound with a separator 6 slightly wider than the sheet-shaped electrodes 4 and 5 and having a thickness of 38 μm inserted and fixed. Outer can 1 with built-in and mounted negative electrode terminal
An organic electrolyte battery (see FIG. 6) having the same configuration except that an insulating plate 7a was disposed on the inner bottom wall side of the above was manufactured.

For each of the 100 organic electrolyte batteries having the structure according to each of Examples 2 and 3 and Comparative Examples 3 and 4, the electrode group 2
And the open circuit voltage good rate of the battery were examined. Further, a round bar having a diameter of 6 mm was arranged on the side wall surface of these organic electrolyte batteries, and a weight of 9 kg was dropped freely on the round bar from a height of 60 cm, and the rate of occurrence of ignition due to impact was tested. Table 2 shows these results together.
Shown in

[0038] The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention.

[0039]

According to the first to fourth aspects of the present invention, in the manufacturing process of the electrode group, the occurrence of winding misalignment is reduced and avoided, so that an organic electrolyte battery with high safety or reliability is provided. You. That is, it is possible to provide an organic electrolyte battery with high safety and the like as a high energy density power supply for portable electronic devices. In addition, since installation of an insulating plate such as a bottom wall surface of the outer can can be omitted, the number of parts is reduced, which is preferable in terms of resource saving and environmental protection.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of a main part of an organic electrolyte battery according to a first embodiment.

FIG. 2 is a plan view showing a configuration example of a sheet-shaped positive electrode of an organic electrolyte battery.

FIG. 3 is a plan view showing a configuration example of a sheet-shaped negative electrode of an organic electrolyte battery.

FIG. 4 is an exploded perspective view showing a configuration of an electrode group included in the organic electrolyte battery according to the first embodiment.

FIG. 5 is an exploded perspective view showing a configuration of an electrode group included in an organic electrolyte battery according to a second embodiment.

FIG. 6 is a longitudinal sectional view showing a configuration of a main part of a conventional organic electrolyte battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Exterior can also serve as a negative electrode terminal 2 ... Electrode group 3 ... Sealing member also serving as a positive electrode terminal 4 ... Sheet positive electrode 4a ... Positive current collecting terminal 4b ... Positive electrode lead 5 ... Sheet negative electrode 5a ... Lithium foil 5b Negative electrode current collector 6, 6 ', 6 "Sheet separator 6a, 6b Folded valley of separator 7a, 7b Insulating plate 8a Safety valve membrane 8b Safety valve membrane support 9 Temperature control element 10 Insulating shield ring

Claims (4)

[Claims] 1. An outer can body having one end opening also serving as a negative electrode terminal, a spiral electrode group mounted in the outer can body by electrically connecting a negative electrode side, and an impregnated carrier carried by the spiral electrode group. An organic electrolyte solution in which the lithium salt is dissolved, and a sealing body which is electrically connected to the positive electrode side of the spiral electrode group and also serves as a positive electrode terminal for insulatingly sealing the opening of the outer can body. An electrolyte battery, wherein the spiral electrode group is a sheet-shaped positive electrode containing a positive electrode active material, an alkali metal or alkali metal alloy-based sheet-shaped negative electrode narrower than the sheet-shaped positive electrode, and The separator is bent at one width end face so as to sandwich the sheet-like positive electrode so as to sandwich the sheet-like positive electrode, and the separator is bent along both surfaces so as to sandwich the sheet-like separator interposed between the two sheet-like electrode plates. Being interposed Organic electrolyte battery and features. 2. The sheet-shaped negative electrode of the spiral electrode group is fixed at one end with an adhesive tape.
The organic electrolyte battery as described in the above. 3. An outer can body having one end opening also serving as a negative electrode terminal, a spiral electrode group mounted in the outer can body by electrically connecting a negative electrode side, and an impregnated support in the spiral electrode group. An organic electrolyte solution in which the lithium salt is dissolved, and a sealing body which is electrically connected to the positive electrode side of the spiral electrode group and also serves as a positive electrode terminal for insulatingly sealing the opening of the outer can body. An electrolyte battery, wherein the spiral electrode group includes a sheet-shaped positive electrode containing a positive electrode active material, a sheet-shaped negative electrode of an alkali metal or alkali metal alloy system, and a sheet interposed between both sheet-shaped electrode plates. The separator has a laminated wound structure, and
An organic electrolyte battery, characterized in that the separator is bent into three parts so as to sandwich the positive electrode and the sheet negative electrode separately, and is positioned along each side while being positioned at each valley. 4. The organic electrolyte battery according to claim 3, wherein the thickness of the sheet-like separator of the spiral electrode group is 20 to 25 μm.