JP2006294309A - Thin battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin battery which can surely exhaust a gas from the inside of the battery in the rise of an internal pressure without increasing a manufacturing cost. <P>SOLUTION: A battery element is housed by an outer package film, battery terminals 2, 3 are exposed to outside from the battery element, and bonding surfaces on the outer periphery of the outer package film on the periphery of the battery element are fused to form the thin battery. Fused part for sandwiching the battery terminals 2, 3 is composed of a sealed part to which the outer package film is fused via a prebonded resin 6 formed on the battery terminals 2, 3 and an unsealed part which is on the inner side than the sealed part. The width of the sealed part in the fused part for sandwiching the battery terminals 2, 3 is set shorter than a width of a sealed part in which the outer package films are sealed with each other without sandwiching the battery terminal, and a hole 21 is formed at the sealed part in which the outer package films are sealed with each other and on the side of the unsealed part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thin battery in which a battery element is housed in a film outer package, and more particularly to a thin battery that can discharge gas inside the battery to the outside when the internal pressure of the battery increases.

  Conventionally, a thin battery in which a battery element is accommodated by two films is known in Patent Document 1 below.

  The thin battery described in Patent Document 1 includes a power generation element in which an electrolyte is sandwiched between a positive electrode plate and a negative electrode plate, and the unit battery cells are stacked via a separator, and a peripheral portion of two exterior films has a predetermined width. The battery main body sealed by heat-sealing and the positive electrode side battery terminal and negative electrode side battery terminal connected to the positive electrode plate and the negative electrode plate of the said power generation element are provided.

Such a thin battery is provided with a narrow portion having a narrow fusion width in a part of the heat fusion portion at the peripheral portion of the outer film. Thereby, even when the power generation element becomes high temperature and the internal pressure rises due to overcharging of the battery, the gas inside the battery can be discharged by opening the fusion part from the narrow width part.
JP 2003-0132868 A

  By the way, when manufacturing a thin battery as described in Patent Document 1 described above, in the step of heat-sealing two exterior films, heat is applied from both the front and back surfaces in a state where the exterior films are overlapped. A heat-sealing is performed by applying a crimping member (heat sealer). However, in this step, in order to form a narrow width portion having a narrower fusion width than other fusion portions, it is necessary to use a special heat sealer having a recessed portion shape for forming the narrow width portion. There was a factor that increased the cost of the manufacturing apparatus.

  Therefore, the present invention has been proposed in view of the above-described circumstances, and an object thereof is to provide a thin battery that can reliably discharge gas from the inside of the battery when the internal pressure is increased without increasing the manufacturing cost. And

  The present invention relates to a thin battery formed by housing a battery element with an exterior film, exposing the battery terminal from the battery element to the outside, and fusing the joint surface of the outer periphery of the exterior film around the battery element. A fusion part sandwiched between a sealing part in which an exterior film is fused via a resin film formed on the battery terminal and an unsealed part inside the battery with respect to the sealing part To do. The width of the sealing part of the fusion part sandwiching the battery terminal is shorter than the sealing width in which the exterior films are sealed without sandwiching the battery terminal, and is the side surface of the unsealed part. And the above-mentioned subject is solved by providing a hole in the part by which exterior films are sealed.

  Further, the present invention is a thin battery formed by housing a battery element with an exterior film, exposing a battery terminal from the battery element to the outside, and fusing a bonding surface of the outer periphery of the exterior film around the battery element. A fusion part sandwiching the battery terminal, a sealing part in which an exterior film is fused via a resin film formed on the battery terminal, and an unsealed part on the battery inner side than the sealing part Form. The above-mentioned problem is solved by making the width of the sealing portion in which the exterior films located on the side surfaces of the unsealed portion are sealed shorter than the widths of the other sealing portions.

  According to the thin battery according to the present invention, the internal pressure is concentrated on the unsealed portion of the battery terminal to open the exterior film, and the hole provided on the side of the unsealed portion or the side surface of the unsealed portion The gas can be discharged from the sealing portion having a short width. Therefore, according to this thin battery, even when using a manufacturing apparatus that makes the entire outer periphery of the outer film uniform in the fusion process of the outer film, the location where the inner film is concentrated and the outer film is easy to open is reduced. Can be formed. Therefore, according to this thin battery, even when a structure for facilitating the opening of the exterior film is formed, gas is reliably discharged from the inside of the battery when the internal pressure is increased without increasing the manufacturing cost. Can be made.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The present invention is applied, for example, to a thin battery configured as shown in FIG. 1A is a top view showing an external appearance of a thin battery, and FIG. 1B is a top view showing an internal configuration of the thin battery.

  As shown in FIG. 1 (b), an electrode active material application portion 1 is formed on the surface of a power generation element (battery body) in which an electrolyte is sandwiched between a positive electrode plate and a negative electrode plate and the unit cells are stacked via a separator. A positive electrode current collector portion 4 and a negative electrode current collector portion 5 for connecting a plurality of unit cells, the positive electrode terminal 2 and the negative electrode terminal 3 are formed at both ends of the electrode active material application portion 1 on the electrode mounting side. ing. The power generation element and the positive electrode terminal 2 and the negative electrode terminal 3 are electrically connected to the positive electrode current collector portion 4 and the negative electrode current collector portion 5.

  In order to increase the fusion strength of the two exterior films in the positive electrode terminal 2 and negative electrode terminal 3 portions on the front and back surfaces of the positive electrode terminal 2 and the negative electrode terminal 3 before the power generation element is accommodated by the two exterior films. A resin 6 (sheet film), which is a resin film, is applied. This leading resin 6 is applied to a portion of the positive electrode terminal 2 and the negative electrode terminal 3 where the exterior film is heat-sealed.

  The power generation element has an exterior film on the back surface and a front surface, and a heat sealer for forming a heat-sealed portion with a uniform width. A body seal portion 7 is formed. Thereby, the power generation element is sealed in the exterior body cup portion 8, and the external shape as shown in FIG. 1 is obtained.

  In such a thin battery, the positive electrode terminal 2 and the negative electrode terminal 3 exposed from the exterior body seal portion 7 are connected to an electrical component or a generator, and discharged according to control of a battery controller (not shown) to supply power to the electrical component. Charge the power from the generator. When the thin battery is overcharged, the temperature inside the outer cup portion 8 is increased due to the temperature rise of the power generation element, and the internal pressure is increased. On the other hand, in the thin battery, when the internal pressure rises abnormally, a part of the exterior body seal portion 7 of the positive electrode terminal 2 and the negative electrode terminal 3 is easily opened to release the gas in the exterior body cup portion 8 to the outside. It has a structure. Hereinafter, this structure will be described.

  As shown in FIG. 2A, the thin battery has a fusion part in which the positive electrode terminal 2 and the negative electrode terminal 3 are sandwiched by an outer film, and an outer body seal part 7 in which the outer films are fused. The fused portion sandwiching the positive electrode terminal 2 and the negative electrode terminal 3 passes through a tip resin 6 which is a resin film formed on the positive electrode terminal 2 and the negative electrode terminal 3 as shown in a cross section in FIG. Then, a sealed portion in which an exterior film made of the laminate resin layer 11, the aluminum foil 12, and the laminate exterior resin 13 is fused, and an unsealed portion on the battery inner side than the sealed portion are formed. In addition, you may provide an unsealed part only in one of the surface of the positive electrode terminal 2 and the negative electrode terminal 3, and a back surface. As a result, as shown in FIG. 3, the width D2 of the sealing part of the fusion part sandwiching the positive electrode terminal 2 and the negative electrode terminal 3 is such that the exterior films are sealed without sandwiching the positive electrode terminal 2 and the negative electrode terminal 3 therebetween. It is shorter than the sealing width D1 of the outer package seal portion 7.

  As shown in FIG. 2 (b), such a fusion part sandwiching the positive electrode terminal 2 and the negative electrode terminal 3 has a formation width of the adhesive resin 6 on the positive electrode terminal 2 and the negative electrode terminal 3, so It is manufactured by being shorter than the width for heat-sealing each other, and then thermocompression-bonding and heat-sealing.

  Further, as shown in FIG. 3, the thin battery is a side surface of the unsealed portion of the positive electrode terminal 2 and the negative electrode terminal 3 which are heat-sealed without forming the leading resin 6, and the exterior films are sealed with each other. A cutout hole 21 is provided in the exterior body seal portion 7. The cutout hole 21 is desirably provided so as to include a straight line obliquely drawn in the exterior body seal portion 7 from both end points in the longitudinal direction of the exterior body seal portion 7 on the battery exterior side of the unsealed portion. In the example of FIG. 3, the cutout holes 21 are provided on both side surfaces of the unsealed portion. However, the cutout holes 21 may be provided only on one side surface of the unsealed portion.

  When such a thin battery is overcharged and the internal pressure of the outer cup portion 8 rises, the internal pressure concentrates on the unsealed portion, and as shown by the arrows in FIG. A concentrated internal pressure is applied. That is, a larger internal pressure is applied to the unsealed portion than the internal pressure applied to the exterior body seal portion 7 that is heat-sealed without sandwiching the positive electrode terminal 2 and the negative electrode terminal 3. And the exterior body seal part 7 of the point A located in the side surface of the unsealed part among the exterior body seal parts 7 starts to explode before the other exterior body seal parts 7, and When the location reaches the cutout hole 21, the gas in the exterior cup portion 8 is discharged to the outside.

  Therefore, according to this thin battery, even if an existing heat sealer that performs heat fusion so as to form an outer package seal portion 7 having a uniform width over the entire outer periphery is used in the heat fusion process, By merely providing a portion where the leading resin 6 is not formed on the battery inner side of the negative electrode terminal 3 to form an unsealed portion, a portion where the internal pressure is concentrated and the exterior body seal portion 7 is easy to open can be formed. . Therefore, according to this thin battery, even when a structure for facilitating the opening of the exterior body seal portion 7 is formed, gas is not supplied from the inside of the battery when the internal pressure is increased without increasing the manufacturing cost. It can be discharged reliably.

  Further, as another configuration of this thin battery, as shown in FIG. 4, the width D12 of the exterior body seal portion 7 located on the side surface of the unsealed portion is replaced with the other exterior, instead of the cutout hole 21 described above. It may be shorter than the width D11 of the body seal portion 7. This thin battery draws a straight line drawn obliquely to the exterior body seal portion 7 from both end points in the longitudinal direction of the exterior body seal portion 7 on the battery exterior side of the unsealed portion, and includes an inner portion of the straight line. Thus, a seal cut region in which the width of the exterior body seal portion 7 is shortened is formed.

  In such a thin battery, the exterior body seal portion 7 in which the exterior films are sealed without sandwiching the positive electrode terminal 2 and the negative electrode terminal 3 is formed with a uniform width, and then the positive electrode terminal 2 and the negative electrode terminal 3 It is manufactured by cutting out the exterior body seal portion 7 located on the side surface of the unsealed portion, that is, the seal cut region.

  Even in such a thin battery, when the internal pressure of the outer cup portion 8 is increased, the internal pressure is concentrated on the unsealed portion, and the internal pressure is concentrated on both side surfaces of the unsealed portion as shown by arrows in FIG. When the opening distance becomes the width of the shortened exterior body seal portion 7, the gas in the exterior body cup portion 8 is discharged to the outside.

  Therefore, according to this thin battery, even if an existing heat sealer that performs heat fusion so as to form an outer package seal portion 7 having a uniform width over the entire outer periphery is used in the thermal fusion process, By only cutting part of the seal portion 7, gas can be reliably discharged from the inside of the battery when the internal pressure increases.

  The above-described embodiment is an example of the present invention. For this reason, the present invention is not limited to the above-described embodiment, and various modifications can be made depending on the design and the like as long as the technical idea according to the present invention is not deviated from this embodiment. Of course, it is possible to change.

It is a top view which shows the structure of the thin battery to which this invention is applied, (a) shows an external appearance structure, (b) shows an internal structure. It is a figure for demonstrating that a sealing part and an unsealed part are formed on a battery terminal in the thin battery to which this invention is applied, (a) Top view, (b) It is sectional drawing. It is a top view which shows the structure which provided the cut-out hole in the unsealed part side surface of a battery terminal in the thin battery to which this invention is applied. It is a top view which shows the structure which provided the seal cut area | region in the unsealed part side surface of a battery terminal in the thin battery to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrode active substance application part 2 Positive electrode terminal 3 Negative electrode terminal 4 Positive electrode collector part 5 Negative electrode collector part 6 Prefixing resin 7 Exterior body seal part 8 Exterior body cup part 21 Cutout hole

Claims (5)

In a thin battery formed by housing a battery element by an exterior film, exposing a battery terminal from the battery element to the outside, and fusing a bonding surface of an outer periphery of the exterior film around the battery element,
The fusion part sandwiching the battery terminal includes a sealing part in which the exterior film is fused via a resin film formed on the battery terminal, and an unsealed part inside the battery with respect to the sealing part. The width of the sealing part of the fusion part sandwiching the battery terminal is made shorter than the sealing width in which the exterior films are sealed without sandwiching the battery terminal,
A thin battery characterized in that a hole is provided in a side surface of the unsealed portion where the exterior films are sealed.   The fusion part sandwiching the battery terminal forms a resin film on the battery terminal with a width shorter than the sealing width in which the exterior films are sealed without sandwiching the battery terminal, and then fused. The thin battery according to claim 1, wherein the thin battery is manufactured. In a thin battery formed by housing a battery element by an exterior film, exposing a battery terminal from the battery element to the outside, and fusing a bonding surface of an outer periphery of the exterior film around the battery element,
The fusion part sandwiching the battery terminal includes a sealing part in which the exterior film is fused via a resin film formed on the battery terminal, and an unsealed part inside the battery with respect to the sealing part. Part is formed,
A thin battery, wherein a width of a sealing portion in which the exterior films located on the side surfaces of the unsealed portion are sealed is shorter than a width of another sealing portion.   The fusion part sandwiching the battery terminal forms a resin film on the battery terminal with a width shorter than the sealing width in which the exterior films are sealed without sandwiching the battery terminal, and then fused. The thin battery according to claim 3, wherein the thin battery is manufactured. A sealing part in which the exterior films are sealed with a uniform width is formed without sandwiching the battery terminal, and then the exterior films located on the side surfaces of the unsealed part are sealed. The thin battery according to claim 3 or 4, wherein the thin battery is manufactured by cutting a portion.

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