JP4087044B2 - battery - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a battery, and more particularly to a battery that can be reduced in size and weight.
[0002]
[Prior art]
In recent years, electronic devices, particularly mobile wireless terminals such as mobile phones, personal information terminals, and notebook personal computers equipped with communication functions, have been rapidly reduced in size and weight. With the reduction in size and weight of such electronic devices, there is a strong demand for the reduction in size and weight of batteries as power sources used in these electronic devices.
[0003]
In order to meet the above demands, development of a battery in which a power generation cell is sealed with an exterior member such as a laminate film to achieve a reduction in size and weight as compared with the prior art is in progress. FIG. 10 is a schematic perspective view showing a conventional battery. 11 is a schematic cross-sectional view taken along line XI-XI in FIG. 10, and FIG. 12 is a schematic cross-sectional view taken along line XII-XII in FIG. A conventional battery will be described with reference to FIGS.
[0004]
10 to 12, a battery 101 includes a power generation cell 111 held inside an exterior member 105 made of a laminate film and the like, and a negative for supplying a current from the power generation cell 111 to the outside of the battery 101. An electrode 110 and a positive electrode 117 are provided. The exterior member 105 includes a cell part that holds the power generation cell 111 inside and a sealing part 115 for sealing the power generation cell 111 to the cell part.
[0005]
The power generation cell 111 includes a negative electrode current collector 109, negative electrode active materials 108a and 108b, separators 107a and 107b, positive electrode active materials 106a and 106b, and positive electrode current collectors 121a and 121b. A negative electrode current collector 109 is disposed at the center of the power generation cell 111. A negative electrode active material 108 b is disposed on the surface of the negative electrode current collector 109. A separator 107b is disposed on the negative electrode active material 108b. A positive electrode active material 106b is disposed on the separator 107b. A positive electrode current collector 121b is disposed on the positive electrode active material 106b. A negative electrode active material 108 a is disposed under the negative electrode current collector 109. A separator 107a is disposed under the negative electrode active material 108a. A positive electrode active material 106a is disposed under the separator 107a. A positive electrode current collector 121a is disposed under the positive electrode active material 106a. The power generation cell 111 has a thickness of about 500 μm, and the positive electrode current collectors 121a and 121b have a thickness of about 10 to 20 μm.
[0006]
In the battery 101, the negative electrode 110 is disposed so as to be electrically connected to the negative electrode current collector 109 and extend from the power generation cell 111 inside the exterior member 105 to the outside of the exterior member 105. The positive electrode 117 is disposed so as to be electrically connected to the positive electrode current collectors 121 a and 121 b and to extend from the power generation cell 111 inside the exterior member 105 to the outside of the exterior member 105. The exterior member 105 is obtained by coating the front and back surfaces of the aluminum film 103 with laminate film resins 102 and 104.
[0007]
[Problems to be solved by the invention]
The batteries shown in FIGS. 10 to 12 can be made smaller and lighter than conventional box batteries and the like. However, as electronic devices such as portable wireless terminals have become more compact and highly functional in recent years, there is a need for further miniaturization (reduction of occupied volume) and weight reduction while maintaining the output capacity of the battery. Yes.
[0008]
The present invention has been made to solve such problems, and an object of the present invention is to provide a battery that can be reduced in size and weight without reducing the output capacity. is there.
[0020]
[Means for Solving the Problems]
A battery according to the present invention includes a power generation element including an active material, an exterior member that houses the power generation element, and an electrode terminal member. The electrode terminal member extends from the inside of the exterior member to the outside of the exterior member. The active material of the power generation element includes an active material portion exposed on at least a part of the outer peripheral surface of the power generation element. The exterior member includes a conductor film that contacts the active material portion. Electrode terminal member that is conductive film electrically connected to the inside of the exterior member.
[0021]
In this way, the conductor film of the exterior member can be used as a current collector in the power generation element. Therefore, it is not necessary to arrange a current collector separately from the exterior member in the power generation element as in the prior art. For this reason, the volume of the power generation element can be reduced by the volume of the current collector. As a result, it is possible to reduce the size and weight of the battery while maintaining the output capacity of the battery.
[0022]
In addition, the electrode terminal is a connection part between a device in which the battery is incorporated and the battery, and requires a certain degree of mechanical strength. For this reason, if a relatively strong metal or the like is used as the electrode terminal member to be the electrode terminal, the strength of the electrode terminal can be reliably improved.
[0023]
Further, since the power generation element is housed inside the exterior member, the conductor of the exterior member is positioned so as to surround the power generation element. Since this conductor acts as a current collector, the conductor of the exterior member is kept at a constant potential. Therefore, the conductor acts as an electric shield (electromagnetic shield or electrostatic shield) that protects the power generation element from magnetism outside the battery. As a result, it is possible to prevent problems such as fluctuations in battery characteristics due to the influence of magnetism from outside the battery.
[0024]
Above Symbol batteries, it is not preferable that are connected at least two places and the electrode terminal member and the conductive film.
[0025]
In this case, even if a failure such as disconnection occurs in one of the two connection portions between the conductor film and the electrode terminal member, the connection between the conductor film and the electrode terminal member is acceptable if the other connection portion is healthy. Can keep. Therefore, it is possible to reduce the probability of occurrence of a defect that the conductor film and the electrode terminal member are disconnected.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.
[0032]
( Reference example )
FIG. 1 is a schematic perspective view showing a reference example of a battery according to the present invention. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1, and FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. The battery will be described with reference to FIGS.
[0033]
1 to 3, the battery 1 supplies a power generation cell 11 as a power generation element held inside an exterior member 5 made of an aluminum laminate film, and supplies current from the power generation cell 11 to the outside of the battery 1. And a positive electrode 13 as an electrode terminal portion. The exterior member 5 includes a cell part that holds the power generation cell 11 therein and a sealing part 15 for sealing the power generation cell 11 to the cell part.
[0034]
The power generation cell 11 includes a negative electrode current collector 9, negative electrode active materials 8a and 8b, separators 7a and 7b, and positive electrode active materials 6a and 6b as active material portions. A negative electrode current collector 9 is disposed in the central portion of the power generation cell 11. A negative electrode active material 8 b is disposed on the surface of the negative electrode current collector 9. A separator 7b is disposed on the negative electrode active material 8b. A positive electrode active material 6b as an active material portion is disposed on the separator 7b. A negative electrode active material 8a is disposed under the negative electrode current collector 9. A separator 7a is disposed under the negative electrode active material 8a. A positive electrode active material 6a as an active material portion is disposed under the separator 7a. The positive electrode active materials 6 a and 6 b are exposed on the outer peripheral surface of the power generation cell 11.
[0035]
The exterior member 5 is obtained by coating the front and back surfaces of an aluminum foil 3 as a conductor film with laminate film resins 2 and 4. As the laminate film resins 2 and 4, for example, polymer resins such as polyethylene, polypropylene, and polyethylene terephthalate can be used. The thickness of the aluminum foil 3 is 30 to 40 μm, and the thicknesses of the laminate film resins 2 and 4 are 50 to 60 μm, respectively. The exterior member 5 has a bag-like form so as to accommodate the power generation cell 11 therein. In the exterior member 11, the laminate film resin 4 is removed on the surface facing the power generation cell 11, and the surface of the aluminum foil 3 is exposed. Since the exposed surface of the aluminum foil 3 and the positive electrode active materials 6a and 6b are in contact with each other, the aluminum foil 3 functions as a positive electrode current collector.
[0036]
For this reason, it is not necessary to arrange | position a positive electrode electrical power collector separately from the exterior member 5 in the electric power generation cell 11 conventionally. Therefore, the volume and mass of the power generation cell 11 can be reduced from the conventional power generation cell by the volume and mass of the omitted positive electrode current collector. As a result, the battery 1 can be reduced in size and weight while maintaining the output capacity of the battery 1.
[0037]
Further, since the laminate film resin 4 (laminate film resin 4 facing the inside holding the power generation cell 11 of the exterior member 5) on the surface of the exterior member 5 facing the power generation cell 11 is removed, the removed laminate The thickness of the battery 1 can be made thinner than before by the thickness of the film resin 4. As a result, the battery 1 can be further reduced in size and weight.
[0038]
In the battery 1, the aluminum foil 3 of the exterior member 5 is positioned so as to surround the power generation cell 11. The aluminum foil 3 functions as a positive electrode current collector. Therefore, the aluminum foil 3 is kept at a constant potential. Therefore, the aluminum foil 3 can act as an electrical shield (electromagnetic shield or electrostatic shield) that protects the power generation cell 11 from magnetism from the outside of the battery 1. As a result, it is possible to prevent the problem that the characteristics of the battery 1 fluctuate due to the influence of magnetism from the outside of the battery 1.
[0039]
In addition, since aluminum has a relatively low electric resistance, the electric resistance of the positive electrode current collector can be reduced.
[0040]
The battery 1 shown in FIGS. 1 to 3 is a so-called envelope-type battery having a structure in which the power generation cell 11 is wrapped with a bag-shaped exterior member 5. Can be easily adhered to the surface of the power generation cell 11. Therefore, the aluminum foil 3 is exposed on the inner surface of the exterior member 5, and the positive electrode active materials 6a and 6b and the aluminum foil 3 can be easily brought into close contact with each other. It can be used as an electric body.
[0041]
In the portion that becomes the outer peripheral surface of the exterior member 11, the cutout portion 12 is formed by removing a part of the laminate film resin 2 in the sealing portion 15. In the cutout portion 12, the aluminum foil 3 is exposed to form a positive electrode 13 as an electrode terminal portion.
[0042]
Thus, in the exterior member 5, since the positive electrode 13 is formed by exposing the aluminum foil 3 in the part used as the outer peripheral surface of the battery 1, the terminal member different from the aluminum foil 3 as a positive electrode, etc. Is not required to be added to the battery 1. For this reason, size reduction and weight reduction of the battery 1 can be achieved more reliably.
[0043]
Further, since the positive electrode 13 can be formed by a relatively simple process of removing a part of the laminate film resin 2 from the exterior member 5, the manufacturing cost of the battery 1 can be reduced compared to the case where an electrode terminal or the like is separately prepared as the positive electrode. Can be reduced. Moreover, since a part of the laminate film resin 2 is removed from the exterior member 5, the battery 1 can be further reduced in size and weight. Moreover, the planar external shape of the positive electrode 13 can be changed to an arbitrary shape by changing the shape of the notch 12.
[0044]
Further, since the sealing portion 15 is a region where the exterior member 5 is overlapped and fixed by a thermocompression bonding method or the like, the sealing portion 15 has higher mechanical strength than other regions of the exterior member 5. Therefore, if the positive electrode 13 is provided in the sealing portion 15, sufficient mechanical strength can be secured for the positive electrode 13.
[0045]
The negative electrode 10 is electrically connected to the negative electrode current collector 9 of the power generation cell 11 and is disposed so as to extend from the inside of the exterior member 5 to the extended portion 16 outside the exterior member 5. ing.
[0046]
Although the positive electrode 13 is formed in the sealing part 15 in the battery 1 shown in FIGS. 1-3, you may provide the positive electrode 13 in another part as shown in FIG. FIG. 4 is a schematic perspective view showing a modification of the reference example of the battery according to the present invention. FIG. 5 is a schematic sectional view taken along line VV in FIG.
[0047]
4 and 5, battery 1 basically has the same structure as the battery shown in FIGS. 1 to 3, but the position of positive electrode 13 as the electrode terminal portion is shown in FIGS. Different from batteries. 4 and 5, the positive electrode 13 is formed on the extending portion 16 of the exterior member 5. That is, the positive electrode 13 is formed on the surface of the extending portion 16 by forming the cutout portion 14 from which a part of the laminate film resin 4 is removed and exposing the aluminum foil 3. Also with such a battery 1, the same effect as the battery shown in FIGS. 1-3 can be acquired.
[0048]
Since the positive electrode 13 can be easily formed by removing a part of the laminate film resin 4 of the exterior member 5 and exposing the aluminum foil 3, the position of the positive electrode 13 in the battery shown in FIGS. It can be easily formed at a different position. For example, on the surface of the battery 1 located on the opposite side of the negative electrode 10 of the battery 1 or another sealing part 15 located on the opposite side of the sealing part 15 on which the positive electrode 13 is formed in FIG. The positive electrode 13 may be formed.
[0049]
(In the form state of implementation)
Figure 6 is a schematic perspective view showing the shape condition of the embodiment of the cell according to the present invention. 7 is a schematic cross-sectional view taken along line VII-VII in FIG. 6, and FIG. 8 is a partially enlarged schematic cross-sectional view in FIG. The battery will be described with reference to FIGS.
[0050]
Referring to FIGS. 6 to 8, battery 1 basically has the same structure as the battery shown in FIGS. 1 to 3, but the structure of positive electrode 17 is different. That is, in the battery 1 shown in FIGS. 1 to 3, the positive electrode 13 is formed by forming the notch 12 that exposes the aluminum foil 3 acting as the positive electrode current collector on the outer peripheral surface of the battery 1. On the other hand, in the battery 1 shown in FIGS. 6 to 8, the positive electrode terminal 17 as the electrode terminal member is arranged so as to extend from the inside of the exterior member 5 to the outside. The end 18 of the positive electrode terminal 17 is connected to the aluminum foil 3 by a spot weld 19 inside the exterior member 5.
[0051]
If it does in this way, the aluminum foil 3 as a conductor film of the exterior member 5 can be utilized as a positive electrode electrical power collector in the power generation cell 11 similarly to the battery 1 by the reference example of this invention. Therefore, it is not necessary to arrange a positive electrode current collector separately from the exterior member 5 in the power generation cell 11 as in the prior art. As a result, the battery can be reduced in size and weight while maintaining the output capacity of the battery 1.
[0052]
Moreover, the electrode in a battery is a connection part with an external apparatus, and a certain amount of mechanical strength is required. For this reason, if a relatively high strength metal or the like is used as the positive electrode terminal 17 serving as the positive electrode, the strength of the electrode composed of the positive electrode terminal 17 can be reliably improved.
[0053]
Further, similarly to the battery according to the reference example of the present invention, the aluminum foil 3 of the exterior member 5 disposed so as to surround the power generation cell 11 functions as a positive electrode current collector, and thus is maintained at a constant potential. Therefore, the aluminum foil 3 can be used as an electric shield (electromagnetic shield or electrostatic shield) for protecting the power generation cell 11 from magnetism outside the battery.
[0054]
In the batteries shown in FIGS. 6 to 8, the aluminum foil 3 and the positive electrode terminal 17 are connected by one spot welded portion 19, but as shown in FIG. 9, a plurality of the positive electrode terminal 17 and the aluminum foil 3 are provided. You may connect at a point. Figure 9 is a partially enlarged schematic cross-sectional view showing a modified example of the form status of implementation of the battery according to the present invention. FIG. 9 corresponds to FIG.
[0055]
Referring to FIG. 9, in battery 1, positive electrode terminal 17 includes bifurcated ends 20 a and 20 b. The ends 20a and 20b are connected to the aluminum foil 3 of the exterior member 5 at two spot welds 19a and 19b, respectively.
[0056]
In this way, even if a defect such as disconnection occurs in either one of the spot welded portions 19a and 19b, which are two connecting portions between the aluminum foil 3 and the positive electrode terminal 17, any of the spot welded portions 19a and 19b is generated. If it is sound, the connection between the aluminum foil 3 and the positive electrode terminal 17 can be maintained.
[0057]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.
[0058]
【The invention's effect】
Thus, according to the present invention, by using the conductor film in the battery exterior member as the current collector of the power generation cell, the battery can be reduced in size and weight while maintaining the output capacity.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a reference example of a battery according to the present invention.
FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG.
FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG.
FIG. 4 is a schematic perspective view showing a modification of the reference example of the battery according to the present invention.
5 is a schematic cross-sectional view taken along line VV in FIG.
6 is a schematic perspective view showing the shape condition of the embodiment of the cell according to the present invention.
7 is a schematic cross-sectional view taken along line VII-VII in FIG.
FIG. 8 is a partial enlarged cross-sectional schematic diagram of FIG. 7;
It is a partially enlarged schematic cross-sectional view showing a modified example of the form status of implementation of the battery according to the present invention; FIG.
FIG. 10 is a schematic perspective view showing a conventional battery.
11 is a schematic cross-sectional view taken along line XI-XI in FIG.
12 is a schematic cross-sectional view taken along line XII-XII in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Battery, 2, 4 Laminate film resin, 3 Aluminum foil, 5 Exterior member, 6a, 6b Positive electrode active material, 7a, 7b Separator, 8a, 8b Negative electrode active material, 9 Negative electrode collector, 10 Negative electrode, 11 Power generation cell , 12, 14 Notch part, 13 Positive electrode, 15 Sealing part, 16 Extension part, 17 Positive terminal, 18, 20a, 20b End part, 19, 19a, 19b Spot welding part.

Claims (2)

A power generation element including an active material;
An exterior member that houses the power generation element;
An electrode terminal member extending from the inside of the exterior member to the outside of the exterior member;
The active material of the power generation element includes an active material portion exposed on at least a part of the outer peripheral surface of the power generation element,
The exterior member includes a conductor film that contacts the active material portion,
The battery, wherein the electrode terminal member is electrically connected to the conductor film inside the exterior member. The battery according to claim 1 , wherein the electrode terminal member and the conductor film are connected at least at two locations.

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