JP4604500B2 - battery - Google Patents

Description

  The present invention relates to a battery in which a power generation element is housed in a battery case made of a flexible sheet such as an aluminum laminate sheet.

  In portable electronic devices and the like, batteries that are thin and light have been conventionally used by using an aluminum laminate sheet for a battery case that houses a power generation element. FIG. 4 shows a conventional configuration example of a non-aqueous electrolyte secondary battery using such a flexible battery case.

  The power generation element 1 of this non-aqueous electrolyte secondary battery is obtained by forming a positive electrode and a negative electrode wound in a cylindrical shape through a separator into flat shapes by crushing the side surfaces in the vertical direction. In addition, the positive electrode and the negative electrode are wound while being shifted back and forth in the winding axis direction, so that the aluminum foil as the active material uncoated portion of the positive electrode protrudes from the front end and the rear end. The copper foil which is a negative electrode active material non-application part is made to protrude in a part. The positive electrode aluminum foil protruding at the front end of the power generation element 1 is welded with the positive electrode lead terminal 2, and the negative electrode copper foil protruding at the rear end is welded with the negative electrode lead terminal 3. Yes.

  The battery case 4 that houses the power generating element 1 is composed of two aluminum laminate sheets 41 and 42. These aluminum laminate sheets 41 and 42 are flexible rectangular sheets in which a base film layer made of nylon resin or the like, a metal layer made of aluminum foil, and a sealant layer made of polypropylene or the like are laminated in a laminate. In addition, since these aluminum laminate sheets 41 and 42 have flexibility, but hardly generate elongation, in order to have a bulge in which the power generating element 1 is fitted in advance in advance, most of the aluminum laminate sheets 41 and 42 are preliminarily placed in the center. The concave sheet portions 41a and 42a are formed by drawing. The two aluminum laminate sheets 41 and 42 configured in this manner are stacked with the sealant layer sides facing each other with the power generation element 1 sandwiched therebetween, and the upper and lower halves of the power generation element 1 are respectively provided with respective concave sheet portions 41a, The battery case 4 in which the power generation element 1 is hermetically sealed is housed by being fitted into the 42a and thermally welding the four peripheral edges. Further, the lead terminals 2 and 3 protruding from the front and rear end faces of the power generation element 1 are sealed through the overlap between the front and rear peripheral portions of the two aluminum laminate sheets 41 and 42 so as to protrude to the outside. It has become.

  Since the non-aqueous electrolyte secondary battery completely seals the inside of the battery case 4 after injecting the non-aqueous electrolyte in a vacuum, the power generation element 1 is then returned to the atmospheric pressure environment. The inside in which is stored is in a reduced pressure state. In such a normal environment, the concave sheet portions 41a and 42a of the aluminum laminate sheets 41 and 42 are pressed by the atmospheric pressure to press the side surfaces of the power generating element 1, thereby causing the wound positive electrode and negative electrode to It can be brought into close contact with an appropriate pressure through the separator.

  However, when the non-aqueous electrolyte secondary battery is used, for example, in a decompression chamber or outside the atmosphere, the pressure that presses the concave sheet portions 41a and 42a is reduced, and the force pushing the side surface of the power generation element 1 is weakened. In addition, the gap between the positive electrode and the negative electrode swells to increase the distance between the electrodes, resulting in a problem that the battery performance deteriorates.

  The power generation element is hermetically housed in the first battery container made of a flexible sheet, and the first battery container is hermetically housed in the second battery container made of metal or the like, and the first battery container and the second battery container Conventionally, a battery having a space of at least atmospheric pressure has been proposed (see, for example, Patent Document 1). However, this battery uses a metal or the like for the second battery container so that the power generation element can be always compressed with a pressure higher than the atmospheric pressure when the power generation element is insufficiently compressed by atmospheric pressure. The internal volume of the second battery container is not easily changed according to the external pressure. Therefore, in such a battery, the advantage that thin and lightweight can be achieved by using a flexible sheet for the battery case is impaired.

A battery in which a power generating element is double sealed with a first battery container and a second battery container, both of which are made of flexible sheets, has been conventionally proposed (for example, see Patent Document 2). However, as described in the paragraph “0036” of Patent Document 2, this battery has a description that it is preferable to deaerate the inside of the second battery container before sealing, rather than double the battery case. However, since it is ideal to be integrated for thinning, the original purpose is not to have such a double structure. By performing the sealing process of the power generation element in two stages, sealing by the electrolytic solution adhesion is performed. The purpose is to eliminate poor wear.
JP-A-9-283177 Japanese Patent Laid-Open No. 2000-200587

  The present invention solves the problem that the battery performance is deteriorated by the fact that the battery case made of the flexible sheet is duplicated by interposing a compression means such as a compression gas so that the power generation element is not sufficiently compressed in a reduced pressure environment. It is what.

The first aspect of the present invention is a battery in which a sealed battery having a first battery container made of a flexible sheet is hermetically housed in a second battery container made of a flexible sheet. A pressure gas for compressing at least a part of the first battery container is disposed between the container and the pressure in the second battery container is higher than the pressure in the external environment in a reduced pressure environment, and The pressure in the first battery container is higher .
The invention of claim 2 is characterized in that the decompressed environment is outside the atmosphere.

The invention of claim 3 is characterized in that the first battery container comprises a flexible sheet in which a sealant layer is laminated on both sides of a metal layer made of aluminum foil,
According to a fourth aspect of the present invention, the first battery container includes a recess for fitting a power generation element in a central portion.

According to the first aspect of the present invention, the pressure gas for compressing the first battery container is disposed between the first battery container and the second battery container, and the second battery container is placed in a reduced pressure environment. The pressure of the external battery is higher than the pressure of the external environment and higher than the pressure in the first battery container. Therefore, even if the pressure of the external environment decreases, the first battery container is higher than the pressure of the external environment. It is possible to prevent the battery performance from being deteriorated due to the excessive distance between the electrodes of the power generation element being compressed by the pressure of the high pressure gas in the second battery container .

  In addition, even if the pressure of the external environment decreases, if the second battery container still has room to expand, the pressure of the external environment further decreases so that the second battery container does not expand further. When the increase in volume disappears, the pressure of the compression gas increases. In addition, when the second battery container expands due to the elastic deformation, the pressure of the gas for compression increases after the elastic deformation occurs.

  Hereinafter, the best embodiment of the present invention will be described.

  In the present embodiment, a non-aqueous electrolyte secondary battery in which the power generating element 1 is housed in a battery case made of an aluminum laminate sheet will be described as in the conventional example shown in FIG. 1 to 3, the same reference numerals are given to the constituent members having the same functions as those of the conventional example shown in FIG.

  As shown in FIG. 1, the nonaqueous electrolyte secondary battery of this embodiment uses a wound flat power generation element 1 having the same configuration as that of the conventional example. However, the battery case has a double structure including the first battery container 5 and the second battery container 6.

  The first battery container 5 is composed of two aluminum laminate sheets 51 and 52 that are substantially the same as the battery case 4 of the conventional example shown in FIG. 4, and these aluminum laminate sheets 51 and 52 are the battery case of the conventional example. Unlike 4, the outermost base film layer is replaced with a sealant layer. That is, these aluminum laminate sheets 51 and 52 are flexible rectangular sheets in which a sealant layer made of polypropylene or the like is laminated on both surfaces of a metal layer made of aluminum foil, and the inner and outer layers are formed by two sealant layers. Thermal welding is possible on both sides. The second battery container 6 includes two resin laminate sheets 61 and 62. These resin laminate sheets 61 and 62 are flexible rectangular sheets in which a base film layer made of nylon resin or the like as an outer layer and a sealant layer made of polypropylene or the like as an inner layer are laminated in a laminate.

  The two aluminum laminate sheets 51 and 52 of the first battery container 5 are overlapped from above and below with the power generation element 1 interposed therebetween, so that the power generation element 1 between them can be centered beforehand in advance. The concave sheet portions 51a and 52a are formed in the most part by drawing. Further, since the resin laminate sheets 61 and 62 of the second battery container 6 are overlapped from above and below the first battery container 5, the swelling of the concave sheet portions 51a and 52a of the first battery container 5 is caused to pass through a slight gap. Recessed sheet portions 61a and 62a in which the sealant layer side of the inner surface is recessed by drawing are formed in advance in most of the center in advance.

  As shown in FIG. 2, the two aluminum laminate sheets 51 and 52 of the first battery container 5 overlap the peripheral portions from above and below, and the upper half and the lower half of the power generating element 1 sandwiched therebetween. It fits in each concave sheet part 51a, 52a. Further, the lead terminals 2 and 3 projecting from the front and rear end faces of the power generation element 1 project outside through the overlap between the front and rear peripheral portions of the two aluminum laminate sheets 51 and 52, as in the conventional example. Let The two resin laminate sheets 61 and 62 of the second battery container 6 are overlapped from above and below the aluminum laminate sheets 51 and 52 of the first battery container 5 with the sealant layers on the inner surfaces facing each other. The bulges of the concave sheet portions 51a and 52a of the battery container 5 are fitted into the concave sheet portions 61a and 62a, respectively. Therefore, the four laminated sheets 51, 52, 61, 62 are overlapped with each other only at the four peripheral edges of the square.

  The inside of the non-aqueous electrolyte secondary battery of the present embodiment is sealed by heat-pressing the peripheral portions of the four laminate sheets 51, 52, 61, 62 from above and below and thermally welding them. Accordingly, between the upper aluminum laminate sheet 51 and the resin laminate sheet 61 and between the lower aluminum laminate sheet 52 and the resin laminate sheet 62, there is a gap between the concave sheet portions 51a and 52a and the concave sheet portions 61a and 62a. Outside air remains in the slight gaps and intervenes as the compression air 7. However, the inside of the concave sheet portions 51a and 52a of the first battery container 5 is not completely sealed here, and a liquid injection port is provided in part so as to communicate with the outside. Such a liquid injection port is formed by, for example, heat-welding a resin piece having a heat resistance between the peripheral portions of the aluminum laminate sheets 51 and 52 and having a property that is difficult to be familiar with the sealant layer. It can be formed by drawing. Then, the nonaqueous electrolyte secondary battery is moved into a vacuum, the inside of the concave sheet portions 51a and 52a is evacuated, the nonaqueous electrolyte is injected, and the power generation element 1 is precharged. By welding, the inside of the battery case 4 is completely sealed. Therefore, since the inside of the first battery container 5 in which the power generation element 1 is housed is sealed in a substantially vacuum state, the non-aqueous electrolyte secondary battery has an aluminum laminate sheet 51, The concave sheet portions 51 a and 52 a of 52 are bent and come into close contact with the outer shape of the power generation element 1. However, since the gap between the concave sheet portions 51a and 52a and the outer shape of the power generation element 1 cannot be completely eliminated, the inside of the battery case 4 is in a state close to a vacuum sufficiently reduced from the atmospheric pressure. Become. Further, since the compression air 7 is contained in a slight gap between the first battery container 5 and the second battery container 6, the atmospheric pressure is the same as that in the external environment.

  In the nonaqueous electrolyte secondary battery having the above configuration, when the pressure of the external environment decreases, the volume of the gap containing the compression air 7 between the first battery container 5 and the second battery container 6 increases. As shown in FIG. 3, the concave sheet portions 61a and 62a of the second battery container 6 swell. When the pressure in the external environment further decreases, the second battery container 6 does not swell any further, and the pressure of the compression air 7 becomes higher than the pressure in the external environment. The power generation element 1 is pressed by being compressed by the pressure of the compression air 7. For this reason, when the pressure of the external environment falls below a pressure slightly lower than the atmospheric pressure, even if the external environment becomes a vacuum, the power generation element 1 is always compressed by the pressure air 7 at a pressure slightly lower than the atmospheric pressure. As a result, it is possible to reliably prevent the battery performance from deteriorating due to the distance between the electrodes of the power generating element 1 being too large.

  Therefore, the non-aqueous electrolyte secondary battery of this embodiment is a battery even when used in an environment where the atmospheric pressure is lower than atmospheric pressure, such as in an extremely high environment, outside the atmosphere, or in a decompression chamber. It can be used without degrading performance.

  In the above embodiment, the case where the four laminate sheets 51, 52, 61, 62 of the first battery container 5 and the second battery container 6 are collectively heat-welded in the atmosphere is shown. 5 and the second battery container 6 need only be able to intervene with the air 7 for compression, so that the heat welding process can be arbitrarily changed depending on the production technology. . For example, using only the aluminum laminate sheets 51 and 52 of the first battery container 5, the power generation element 1 is completely enclosed as in the case of the conventional example, and then the resin of the second battery container 6 from above and below in the atmosphere. Laminate sheets 61 and 62 may be heat-welded. Further, the peripheral portions of the aluminum laminate sheets 51 and 52 and the resin laminate sheets 61 and 62 are thermally welded in the air in advance, and thereafter, the upper and lower laminate sheets 51 and 61 and the laminate sheets 52 and 62 are conventionally attached. As in the case of the aluminum laminate sheets 41 and 42 in the battery case 4 of the example, heat welding may be performed in a vacuum. Further, the four laminate sheets 51, 52, 61, 62 are thermally welded in a vacuum, and after the power generation element 1 is completely sealed, between the aluminum laminate sheets 51, 52 and the resin laminate sheets 61, 62, respectively. It is also possible to inject the compression air 7. In this case, the injection port for the compression air 7 may be opened from the beginning in the resin laminate sheets 61 and 62 or may be opened at the time of injection and sealed after the injection of the compression air 7.

  Moreover, in the said embodiment, although the case where the resin laminate sheets 61 and 62 of the 2nd battery container 6 were comprised with the material which hardly produces elongation was shown, this resin laminate sheets 61 and 62 produce elongation by elastic deformation. It can also be a material. However, in this case, since the degree of swelling of the second battery container 6 also changes according to the degree of decrease in the pressure of the external environment, the pressure of the compression air 7 decreases as the pressure of the external environment decreases. The force that presses the power generation element 1 is also reduced.

  Moreover, in the said embodiment, the concave sheet part 51a, 52a, 61a, 62a of the 1st battery container 5 and the 2nd battery container 6 is formed in both the upper and lower laminate sheets 51 and 61 and the laminate sheets 52 and 62 each. However, it is also possible to form only one of the upper and lower laminate sheets 51 and 61 or the laminate sheets 52 and 62 and use a flat sheet as it is for the other. Further, flat sheets can be used for both the upper and lower laminate sheets 51, 52, 61, 62. Furthermore, in the said embodiment, although the case where the 1st battery container 5 and the 2nd battery container 6 were each comprised by the two aluminum laminate sheets 51 and 52 and the resin laminate sheets 61 and 62 was shown, for example, one sheet It is also possible to use a laminate sheet that is folded in two or in the form of a bag. Furthermore, the laminate sheet used for the first battery container 5 and the second battery container 6 may be one in which the shape of the concave sheet portion and the sheet shape are different from each other.

  Moreover, in the said embodiment, while the 1st battery container 5 was comprised with the aluminum laminate sheets 51 and 52, and the 2nd battery container 6 was comprised with the resin laminate sheets 61 and 62, the 1st battery container 5 was shown. Can be made of a resin laminate sheet, and the second battery container 6 can be made of an aluminum laminate sheet. However, since polypropylene or the like of the sealant layer may infiltrate moisture or the like from the end surface through the interlayer of the welded portion, it is preferable to use a resin laminate sheet that can completely block the moisture for the inner first battery container 5. . Further, the sheet material constituting the first battery container 5 and the second battery container 6 may be a flexible sheet that can secure sufficient strength and barrier property and can be surely sealed by both of them. A resin laminate sheet made of only resin can be used for both the first battery container 5 and the second battery container 6, and these need not be laminated sheets. Furthermore, the overlapping portions of these flexible sheets can be sealed by other methods such as adhesion instead of heat welding. In particular, when the first battery container 5 and the second battery container 6 are sealed in separate processes, since the sealant layer that does not need to be welded in that process is melted in the thermal welding, a difference is provided in the welding temperature. However, in the case of adhesion or the like, such an obstacle is eliminated.

  In addition, since it is preferable that the nonaqueous electrolyte secondary battery does not have unnecessary swelling under an atmospheric pressure environment, in the above embodiment, if the external environment is the atmospheric pressure, the resin laminate sheet 61 of the second battery container 6 is used. , 62 shows a case where there is still a room to swell, but the second battery container 6 may be already swelled to the limit under this atmospheric pressure environment. In this case, if the pressure in the external environment decreases even a little, a pressure greater than that in the external environment is applied to the first battery container 5. Furthermore, in the said embodiment, when the external environment fell below atmospheric pressure, the case where it was made to be able to compress the electric power generation element 1 with the air 7 for compression was shown, but the pressure of the external environment used as this reference | standard is not necessarily It is not necessary to be atmospheric pressure, and the pressure of the pressure air 7 may be configured to be equal to the pressure of the external environment in a higher or lower pressure environment. Moreover, the pressure in the external environment is not necessarily the pressure in the gas, such as the atmospheric pressure in the atmosphere, and may be the pressure in the liquid, such as water pressure. Therefore, for example, when a non-aqueous electrolyte secondary battery that is often used in deep water is brought into shallow water or pulled into the atmosphere, the second battery container 6 expands and presses the first battery container 5. You may do it.

  Moreover, although the case where the air 7 for compression taken in from external air was used was shown in the said embodiment, the gas for compression for compressing the 1st battery container 5 does not necessarily need to be air, and other gas is used. It can also be used. Furthermore, the compression gas only needs to be a gas when the pressure in the external environment has fallen insufficiently to press the power generation element 1. Or it may solidify and change into liquid or solid.

  Moreover, in the said embodiment, although the case where the 2nd battery container 6 covered the 1st battery container 5 substantially completely except a peripheral part was shown, the sheet | seat part which covers at least the electric power generation element 1 (it is a concave sheet in the said embodiment) It suffices if the portions 51a and 52a) are covered with a gas for compression. Further, the second battery container 6 may completely cover the first battery container 5 including the peripheral part. That is, for example, the resin laminate sheets 61 and 62 of the second battery container 6 can be enlarged and sealed separately outside the sealing portion of the first battery container 5.

  Moreover, although the case where the winding type and flat power generation element 1 is used is shown in the above embodiment, the distance between the electrodes can be set by applying pressure from the outside of the first battery container 5 to the external environment or the pressure air 7. As long as the power generation element is maintained, the configuration of the power generation element 1 is arbitrary, and a cylindrical wound type or a laminated type can also be used. Furthermore, although the non-aqueous electrolyte secondary battery has been described in the above embodiment, the type of the battery is arbitrary, and can be similarly applied to other secondary batteries and primary batteries.

In the above embodiment, in order to compress the first battery container 5, but was interposed compression gas between the second battery container 6, in the reference embodiment, the liquid or in place of the compression gas gel A sufficient amount may be interposed.

1 is an exploded perspective view showing a structure of a nonaqueous electrolyte secondary battery according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view illustrating a structure of a nonaqueous electrolyte secondary battery according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view illustrating a structure of a nonaqueous electrolyte secondary battery in a reduced pressure environment according to an embodiment of the present invention. It is a disassembled perspective view which shows a prior art example and shows the structure of a nonaqueous electrolyte secondary battery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power generation element 5 1st battery container 51 Aluminum laminate sheet 52 Aluminum laminate sheet 6 2nd battery container 61 Resin laminate sheet 62 Resin laminate sheet 7 Pressure air

Claims (4)

In a battery formed by sealingly storing a sealed battery including a first battery container made of a flexible sheet in a second battery container made of a flexible sheet,
Between the first battery container and the second battery container, a pressure gas for compressing at least a part of the first battery container is disposed ,
A battery used in a reduced pressure environment, wherein the pressure in the second battery container is higher than the pressure in the external environment and higher than the pressure in the first battery container in a reduced pressure environment . The battery according to claim 1, wherein the decompressed environment is outside the atmosphere. 3. The battery according to claim 1, wherein the first battery container is made of a flexible sheet in which a sealant layer is laminated on each of both surfaces of a metal layer made of an aluminum foil. 4. 4. The battery according to claim 1, wherein the first battery container includes a recess for fitting a power generation element in a central portion. 5.

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