JP2019106243A - Battery exterior material, battery, and method for manufacturing them - Google Patents

Abstract

To provide a battery exterior and battery which can realize both space saving and reduction of manufacturing time.SOLUTION: A battery exterior material (1) has a flange portion (3) around a battery chamber (2) by joining metal foils. The flange portion (3) includes a heat seal portion (6) sandwiching an electrode portion (4) and the other weld portion (5). The heat seal portion (6) is formed by thermal fusion of a folded thermal fusion sheet. A battery (100) includes battery elements in the battery chamber (2).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a battery case, a battery, and a method of manufacturing the same.

  2. Description of the Related Art A secondary battery having a large charge / discharge capacity such as a lithium ion battery is widely used as a portable battery using device such as a mobile phone. The secondary battery includes a battery (a battery chamber) formed by bonding metal foils, a battery element sealed in the battery chamber, and an electrode portion for electrically connecting the inside and the outside of the battery chamber. Are known.

  For example, as the above-mentioned battery, a battery formed by bonding (heat sealing) of a laminated metal foil coated with a resin film by heat fusion of the resin film is known (see, for example, Patent Documents 1 and 2) ). Moreover, the peripheral part other than the part which clamps the electrode part of stainless steel foil is welded to the said battery, and the battery which is formed by the heat seal by the heat sealing of the heat sealing sheet | seat which the said holding part is known is known. (See, for example, Patent Document 3).

JP, 2015-103291, A (July 4, 2015 publication) JP, 2013-184290, A (opened on September 19, 2013) Japanese Patent Application Publication No. 2004-052100 (published on February 19, 2004)

  However, in a battery using a laminated metal foil as described above, it is necessary to make the width of the heat seal portion sufficiently large in order to suppress moisture permeation of the heat seal portion. Therefore, there is room for consideration from the viewpoint of space saving.

  In a battery formed by welding a part of the metal foil by welding and the remaining part by heat sealing, the width of the welded portion can be made smaller than the width of the heat sealed portion. Therefore, it is advantageous in terms of space saving. However, both the metal foil and the heat fusible sheet have sufficient flexibility. For this reason, it is difficult to stably arrange two heat fusion sheets on the side edge around the electrode portion in the metal foil without misalignment. For this reason, in the battery which uses said welding and heat seal together, arrangement of a heat sealing sheet takes time, and room for examination is left from a viewpoint of productivity.

  An aspect of the present invention aims to provide a battery case and a battery that can realize both space saving and reduction of manufacturing time.

  In order to solve the above problems, a battery case according to a first aspect of the present invention is formed of a joined metal foil, a battery chamber for housing a battery element, and a periphery of the battery chamber. A flange portion disposed on at least a portion of the metal foil and formed by joining the metal foils, the flange portion being interposed between a weld formed by welding the metal foils and the metal foils And a heat seal portion formed by bonding the metal foil by heat fusion of the heat fusion sheet disposed, the heat fusion sheet being folded between the metal foils. It is arranged.

  In order to solve said subject, the battery which concerns on a 2nd aspect of this invention has said battery exterior material in this invention, and the said battery element accommodated in the said battery chamber.

  In order to solve said subject, the manufacturing method of the battery exterior material which concerns on the 3rd aspect of this invention welds a part of peripheral part of metal foil, and becomes a battery room for accommodating a battery element. A step of forming an internal space, a step of sandwiching a bent heat-fusion sheet in the remaining portion of the peripheral portion, and heating the remaining portion of the peripheral portion to thermally fuse the heat-fusion sheet And heat sealing.

  In order to solve said subject, the manufacturing method of the battery concerning the 4th aspect of this invention is the manufacturing method of said battery exterior material in this invention, Furthermore, the process of accommodating the said battery element in the said internal space is further carried out Including.

  According to the above aspect of the present invention, it is possible to provide a battery case and a battery that can realize both space saving and reduction of manufacturing time.

It is a perspective view which shows typically the battery exterior material or battery which concerns on one embodiment of this invention. It is a figure in the manufacturing process of the battery exterior material or battery which concerns on one embodiment of this invention after metal foil is welded, and is a figure which shows typically the state before heat sealing. (A) is a figure which shows typically the state before being bend | folded of the 1st example of the heat-fusion sheet | seat in one embodiment of this invention, (b) is the 1st of the said heat-fusion sheet | seat. It is a figure showing typically the bent state of the example of. (A) is a figure which shows an example in the state in which the heat sealing | fusion sheet | seat was arrange | positioned between metal foil in the manufacture process of the battery exterior material or battery which concerns on one embodiment of this invention, (b) It is a figure which shows the other example of the state by which the heat sealing | fusion sheet | seat is arrange | positioned between metal foil in the said manufacturing process. (A) is a figure which shows typically the 2nd example of the heat-fusion sheet | seat in this Embodiment, (b) is a figure which shows typically the 3rd example of the said heat-fusion sheet | seat. is there. It is a figure which shows typically arrangement | positioning between metal foils of the heat-fusion sheet | seat of the 2nd or 3rd example in the manufacture process of the battery exterior material which concerns on one embodiment of this invention. It is a figure which shows typically the structure of a seam welding apparatus. (A) is a figure which shows typically the structure of the sample A in the evaluation experiment 1, and (b) is a figure which shows the structure of the sample B in the evaluation experiment 1 typically.

  Hereinafter, embodiments of the present invention will be described. FIG. 1 is a perspective view schematically showing a battery case or battery according to an embodiment of the present invention.

[Battery material]
The battery exterior material 1 has a battery chamber 2 and a flange portion 3 as shown in FIG.

  Battery compartment 2 is an internal space for accommodating a battery element. For example, the battery chamber 2 is a space formed by the concave portions when two metal foils having concave portions whose shapes in a plan view are rectangular are overlapped with the concave portions. The shape of the metal foil in plan view is rectangular. The battery chamber 2 is formed of the joined metal foil.

  The metal foil can be appropriately selected from known metal foils in a range having sufficient physical properties (for example, chemical stability and the like) as a battery exterior material. Examples of the material of the metal foil include copper, aluminum, nickel, an alloy containing two or more of them, a nickel plating material, and stainless steel. Examples of stainless steels include austenitic stainless steels and ferritic stainless steels. Among them, austenitic stainless steels are preferable from the viewpoints of strength, weldability and formability.

  The thickness of the metal foil can be appropriately determined in a range having sufficient physical properties (for example, strength and the like) as a battery exterior material. When the thickness of the metal foil is too thin, its strength may be insufficient, welding may be insufficient, and when it is too thick, it becomes heavy. The thickness of the metal foil is preferably 20 μm or more, more preferably 30 μm or more, and still more preferably 40 μm or more from the viewpoint of its strength. The thickness of the metal foil is preferably 100 μm or less, more preferably 70 μm or less, and still more preferably 50 μm or less, from the viewpoint of weight reduction and stability of welding.

  More specifically, the metal foil is an austenitic stainless steel having a tensile strength of 700 MPa or more and an elongation of 45% or more from the viewpoint of strength, chemical stability, and formability and the like. Is preferred.

  If the tensile strength of the austenitic stainless steel of the above-mentioned metal foil is too low, holes may be easily formed in the metal foil when an object hits the surface. The tensile strength of the metal foil is preferably 700 MPa or more, and more preferably 750 MPa or more from the viewpoint of the strength. Further, the upper limit value of the tensile strength of the metal foil can be appropriately determined from the viewpoint of feasibility such as the availability of the metal foil, and for example, it is preferably 900 MPa or less, and 800 MPa or less More preferable. The tensile strength of the metal foil can be measured by a tensile test, and can be adjusted by, for example, annealing or temper rolling.

  When the elongation of the metal foil is too low, the formability of the metal foil may be insufficient. From the viewpoint of the molding processability, the elongation of the metal foil is preferably 45% or more, and more preferably 55% or more. The upper limit value of the elongation of the metal foil can be appropriately determined from the viewpoint of realization such as the availability of the metal foil, and for example, it is preferably 75% or less, more preferably 70% or less . The elongation of the metal foil can be measured by a tensile test, for example it can be enhanced by rolling the metal foil or its material and then annealing in an atmosphere of a noble gas or non-oxidizing gas (such as hydrogen gas) .

  Moreover, it is preferable that the said metal foil does not have resin layers, such as a laminate, on the surface from a viewpoint of the stability of welding.

  The above-mentioned recessed part can be formed by the usual processing methods for forming a recessed part in metal foil, such as drawing processing and overhang processing. From the viewpoint of preventing the occurrence of wrinkles due to processing in the metal foil, particularly the flange portion, the recess is preferably formed by overhang processing.

  The flange portion 3 is disposed all around the battery chamber 2. The flange portion 3 is formed by bonding metal foils. The flange portion 3 is a heat seal portion formed by joining a metal foil by heat fusion of a weld portion 5 formed by welding of the metal foil and a heat fusion sheet disposed between the metal foils. 6 and. The end of the weld 5 is in close contact with or contained in the heat seal 6.

  The weld portion 5 is a portion formed by welding of the metal foil. The weld 5 is formed along the two long sides and one short side of the metal foil. The welding portion 5 is formed on the long side from one short side of the metal foil toward the other short side not welded, to a position having an appropriate distance from the other short side. The above-mentioned interval on the other short side is substantially the same as the seal length of the heat seal portion 6 described later.

  The protruding length (the distance from the side edge of the battery chamber 2 to the side edge of the metal foil, also referred to as the “first protruding length”) of the portion having the weld 5 in the flange portion 3 is airtight and liquid tight by welding. The battery chamber 2 can be properly determined within the range in which the battery chamber 2 can be sealed. If the first projecting length is too small, the plate presser at the time of welding becomes insufficient and a gap is generated between the metal foils. Therefore, welding defects may easily occur, and the battery chamber 2 may not be sufficiently sealed. If the first protrusion length is too large, space saving may be insufficient. The first protrusion length is preferably 3 mm or more, more preferably 6 mm or more, and still more preferably 5 mm or more from the viewpoint of sufficient sealing of the battery chamber 2. Further, from the viewpoint of space saving, the first projection length is preferably 10 mm or less, more preferably 8 mm or less, and still more preferably 6 mm or less.

  The heat seal portion 6 is a part of the flange portion 3 and is a portion formed by heat fusion of a heat fusion sheet. Moreover, the heat seal part 6 is a part which clamps the electrode part 4 among the joining parts of the said metal foil. The heat seal portion 6, which will be described in detail later, is formed by thermal fusion of a thermal fusion sheet in which the electrode portion 4 is inserted through the slit portion of the thermal fusion sheet.

  The protruding length (also referred to as “second protruding length”) of the heat seal portion 6 is the distance from the other end of the battery chamber 2 to the other end of the metal foil. The second protruding length and the length (seal length) of the heat-sealed portion of the heat seal portion 6 both seal the battery chamber 2 airtight and liquid tight by heat sealing. It can be decided appropriately as much as possible. For example, the second projection length can be appropriately determined within a range in which a sufficient seal length can be secured, for example, can be appropriately determined from a length of 90 to 100% of the seal length. It is possible.

  The seal length is preferably 10 mm or more, and more preferably 15 mm or less, from the viewpoint of sufficient sealing of the battery chamber 2 and space saving, for example.

  Generally, the moisture permeability of the weld is sufficiently lower than that of the heat seal. Therefore, the protruding length of the welding portion 5 may be sufficiently shorter than the protruding length of the heat seal portion 6.

  The heat fusion sheet has a bent portion. The heat seal portion 6 is formed by heat fusion of the heat fusion sheet folded at the folded portion. The heat fusion sheet is composed of a continuous phase of a thermoplastic resin. The said thermoplastic resin should just be a thermoplastic resin which can be used for the resin material of the heat-fusion sheet | seat for heat seals, The polyolefins, such as polyethylene and a polypropylene, and a polyethylene terephthalate are contained in the example.

  The thickness of the heat fusion sheet may be in the range in which heat sealing can be performed, and may be, for example, 50 to 150 μm.

  The heat fusible sheet may further include an aggregate for reinforcing the heat fusible sheet from the viewpoint of maintaining the form of the heat fusible sheet. Examples of such aggregates include fillers and non-melting sheets. Examples of such fillers include flexible staple fibers. The non-meltable sheet is a sheet remaining without being melted by heat sealing of a heat-fusion sheet, and examples thereof include nonwoven fabrics and woven fabrics.

  The heat-fusion sheet having the non-melting sheet may be a sheet obtained by laminating the heat-fusion sheet and the non-melting sheet, or may be a commercially available product. Examples of the commercially available products include heat fusion films PPa-F (72), PPa-F (100), PPa-N (72), PPa-N (100) and PPa-Y manufactured by Dainippon Printing Co., Ltd. Is included.

  The state of the heat fusion sheet in the heat seal portion 6 can be confirmed by observation of a cross section of the heat seal portion 6 or ultrasonic waves.

  The bent portion of the heat fusion sheet in the heat seal portion 6 is located at a position continuous with the weld portion 5 in the heat seal portion 6. That is, the heat melting sheet is disposed such that a ridge line formed by bending is positioned at the back of the flange portion 3. The bent portion may be located on the opposite side, that is, on the other short side of the metal foil in the heat seal portion 6.

  The heat-fusion sheet further includes a slit portion which opens along the fold line of the folded portion in the folded state. The slit portion is an opening for inserting the electrode portion 4. The heat seal part 6 is formed by heat fusion of the heat fusion sheet in which the electrode part 4 is inserted in the slit part.

  The electrode portion 4 is held by the flange portion 3, more specifically, by the heat seal portion 6. The electrode unit 4 is a member for electrically connecting the battery element in the battery chamber 2 and the outside of the battery chamber 2. The electrode unit 4 may be a part of the battery element, or may be the configuration of the battery case 1. The position and number of the electrode units 4 are not limited. The electrode portion 4 can be appropriately selected from members usable for the electrode of the battery. For example, examples of the shape of the electrode portion 4 include a plate, a column, and a line. Examples of the material of the electrode portion 4 include aluminum, copper and carbon.

  In the range from which the effect in this Embodiment is acquired, the battery exterior material 1 may have other structures other than the structure mentioned above. The example of the said other structure contains a safety valve other than the electrode part 4 mentioned above.

[Method of manufacturing battery exterior material]
The battery exterior material 1 can be manufactured by the following manufacturing method. The manufacturing method includes the following first to third steps.

  In the first step, a part of the peripheral portion of the metal foil is welded to form an internal space which is a battery chamber for housing the battery element. The first step can be carried out by a welding method that can weld metal foils. Examples of such welding methods include resistance welding, seam welding and laser welding.

  FIG. 2 is a view schematically showing a state after the metal foil is welded and before being heat-sealed in the process of manufacturing the battery exterior material or the battery according to the embodiment of the present invention. In the first step, welds 5 are formed along the three sides (a pair of long sides and one short side at one end) of the metal foil. Thus, three sides (a pair of long sides and one short side at one end) of the battery chamber 2 are sealed in a fluid-tight and air-tight manner by the welding portion 5.

  In the first step, the three sides of the two stacked metal foils are welded, but a portion to be a heat seal portion is left on the electrode portion 4 side of the metal foil. Thus, the two ends (welded ends) of the weld 5 do not extend to the edge of the metal foil.

  The second step is a step of sandwiching the heat-fusion sheet bent at the bending portion in the remaining portion of the peripheral portion of the metal portion. (A) of FIG. 3 is a figure which shows typically the state before being bend | folded of the 1st example of the heat sealing | fusion sheet | seat in one embodiment of this invention. (B) of FIG. 3 is a view schematically showing a bent state of the first example of the heat fusion sheet.

  As shown in FIG. 3A, the heat fusible sheet 7 is an elongated rectangular shape in plan view. The heat fusible sheet 7 has, for example, the same length as the width of the flange portion 3 and has a width twice the width of the heat seal portion 6. Non-woven fabric (not shown) as an aggregate is bonded to one surface of the heat-fusion sheet 7. The heat-fusion sheet 7 has a bent portion 8 passing through the center along the longitudinal direction.

  The heat fusible sheet 7 further has two slit portions 9 opened along the fold lines of the folds 8. The slit 9 is an elongated opening for inserting the electrode 4. The slit portion 9 has a length equal to or slightly larger than the width of the electrode portion 4 and corresponds to a desired position of the electrode portion 4 in the short direction of the battery exterior material 1 It is arranged in seven. The slit portion 9 is formed, for example, by cutting the heat fusion sheet 7 with a cutter such as a cutter knife.

  (A) of FIG. 4 is a figure which shows an example of the state by which the heat sealing | fusion sheet | seat is arrange | positioned between metal foil in the manufacture process of the battery exterior material or battery which concerns on one embodiment of this invention.

  As shown in (a) of FIG. 4, the heat fusible sheet 7 is in the state of being bent at the bent portion 8, the bent portion 8 is directed to the welded portion 5 in the peripheral portion, and the bent portion 8 is a welded portion. It is inserted into the remaining part of the rim until it abuts on 5. Thus, the heat fusible sheet 7 is disposed so as to be held between the remaining portions of the peripheral portion without shifting or falling during movement. The bent portion 8 abuts on the end of the welded portion 5.

  The third step is a step of heating the remaining portion of the peripheral portion to thermally fuse the heat fusion sheet 7 and heat sealing it. The third step can be carried out by a sealing method capable of heat-sealing the heat-fusion sheet 7 sandwiched between metal foils. Examples of the sealing method include a pressing element that generates ultrasonic vibration or a heating and pressing method that is pressed by a heated pressing element. In the third step, the heat fusible sheet 7 is melted, and the resin component adheres so as to wrap the end of the welded portion 5. Thus, the heat seal portion 6 is formed, and the battery chamber 2 is completely sealed in a fluid-tight and air-tight manner.

  As described above, in the present embodiment, the slit portion 9 through which the electrode portion 4 can be inserted is provided in the bent portion 8 of the heat-fusion sheet 7. Then, after the heat fusible sheet 7 is bent, the slit portion 9 is inserted into the electrode portion 4, and the heat fusible sheet 7 is inserted until the bent portion 8 abuts on the two weld ends of the welded portion 5. Then, the outer surface of the metal foil is sandwiched by a heating device such as a heat sealer to thermally fuse the metal foils to each other.

  The above-described manufacturing method may further include other steps other than the above-described first to third steps, as long as the effects of the present embodiment can be obtained. For example, the manufacturing method may further include a fourth step of sandwiching the electrode portion 4 in the remaining portion of the peripheral portion to be the heat seal portion 6.

  The fourth step may be performed by the later third step. For example, the fourth step may be performed simultaneously with the first step, may be performed after the first step but before the second step, or may be performed after the second step.

  More specifically, the electrode portion 4 may be disposed at the other end of the peripheral portion of the metal foil while the battery element 10 is accommodated in the recess in the first step. Also, even if the electrode portion 4 is disposed at the other end of the peripheral portion of the metal foil by being inserted into the appropriate place of the battery element 10 stored in advance in the battery chamber 2 after the welding portion 5 is formed. Good. Alternatively, the electrode portion 4 is inserted into the battery chamber 2 together with the arrangement of the heat fusion sheet 7 in the state of being inserted into the slit part 9 of the heat fusion sheet 7 and arranged at the other end of the periphery of the metal foil. It may be done. Alternatively, the electrode portion 4 is inserted into the battery chamber 2 from the outside of the battery chamber 2 through the slit portion 9 of the heat-fusion sheet 7 disposed at the other end of the peripheral portion of the metal foil. It may be disposed at the other end of the peripheral edge.

  As described above, in the case where the heat fusion sheet 7 has the slit portion 9, the fourth step is performed such that the electrode portion 4 is inserted through the slit portion 9. The electrode portion 4 is easily disposed at a desired position in the short direction of the battery chamber 2 by inserting the slit portion 9, and the position shift in the short direction does not easily occur.

[Battery and its manufacturing method]
A battery 100 according to one embodiment of the present invention includes a battery exterior material 1 and a battery element 10 housed in a battery chamber 2 (see FIGS. 1 and 4). Battery 100 can be manufactured by a method further including the step of housing battery element 10 in the internal space (battery chamber 2) by the recess of the metal foil in the method of manufacturing battery exterior material 1 described above.

  The battery element 10 is configured by a combination of known members constituting a battery. Examples of the components of the battery element 10 include a positive electrode, a negative electrode, a separator, and an electrolyte, and examples of the electrolyte include an electrolytic solution, a solid electrolyte, and a gelled electrolyte. These are appropriately combined to constitute the battery element 10 according to the type of the battery element 10. The type of battery of the battery element 10 may be a primary battery or a secondary battery. Examples of such secondary batteries include lithium ion batteries, lithium polymer batteries, nickel hydrogen batteries and nickel cadmium batteries.

[Modification]
The shape of the metal foil in plan view may not be rectangular. Further, the shape of the above-described concave portion in plan view may not be rectangular. The shape of these planar views may be circular, may be polygonal other than rectangular such as triangle and hexagonal, may be non-circular such as elliptical, etc. It may be in the form of Moreover, the cross-sectional shape of the said recessed part does not need to be a rectangle, and may be other shapes, such as a U-shape or a V-shape, etc. FIG.

  Further, the flange portion may not be disposed all around the battery chamber. For example, the battery chamber may be formed by bending, welding, and heat sealing a sheet of metal foil in which the above-described recess is formed as needed. In this case, the flange portion is formed at a portion other than the folded portion of the metal foil in the peripheral portion of the metal foil. Thus, in the present embodiment, the flange portion is disposed on at least a part of the peripheral portion of the battery chamber.

  Further, the positions of the electrode portion and the heat seal portion are not limited to one end of the both ends of the battery chamber. The electrode portion and the heat seal portion can be disposed at any position of the flange portion 3. For example, in the case where one electrode portion extends outward from each of both end portions of the battery chamber, the heat seal portion is formed at each of both end portions of the metal foil. In this case, the welds 5 are formed on both side edges (long sides) of the metal foil, leaving the seal length of the heat seal 6 at both ends of the metal foil.

  (B) of FIG. 4 is a figure which shows the other example of the state by which the heat sealing | fusion sheet | seat was arrange | positioned between metal foil in the manufacture process of the said battery exterior material. As shown in FIG. 4B, the heat fusible sheet 7 is inserted into one end of the peripheral portion of the metal foil with the bent portion 8 on the outside (opposite to the battery chamber 2), It may be done. Also in this case, the heat fusible sheet 7 is at the peripheral portion of the metal foil until the free end edge of the heat fusible sheet 7 opposite to the bent portion 8 in the short direction reaches the end of the welded portion 5. It is inserted at one end. As described above, in the present embodiment, the position of the bent portion 8 when the heat fusible sheet 7 is inserted into the peripheral portion may be on the battery chamber 2 side or may be on the outside.

  In addition, the heat fusion sheet 7 may further have another configuration other than the slit portion 9. For example, the heat fusible sheet 7 may further have the notches 11 at both longitudinal ends.

  (A) of FIG. 5 is a figure which shows typically the 2nd example of the heat sealing | fusion sheet | seat in this Embodiment. (B) of FIG. 5 is a figure which shows typically the 3rd example of the said heat sealing | fusion sheet | seat. The notch 11 is a portion of the heat-fusion sheet 7 that should be in contact with the weld 5 when the heat-fusion sheet 7 is inserted into one end of the peripheral portion of the metal foil in the second step. Is a cutaway part.

  The notches 11 are formed at both ends outside the slit 9 in the bent part 8 as shown in FIG. 5A. The shape of the notch 11 in a plan view is a shape that is in close contact with the end of the weld 5 or includes the end, and is, for example, V-shaped. Alternatively, when the heat fusible sheet 7 is inserted into one end of the peripheral portion of the metal foil from the free end side, the notch 11 is a bent portion as shown in FIG. 5 (b). It is formed at both longitudinal ends of the heat-fusion sheet 7 at the free edge opposite to 8.

  FIG. 6 is a view schematically showing the arrangement between the metal foils of the heat fusible sheet of the second or third example in the process of manufacturing the battery exterior material according to the embodiment of the present invention. The heat-fusion sheet 7 having the notch 11 is inserted into one end of the peripheral portion of the metal foil with the notch 11 directed to the battery chamber 2. Therefore, when the heat-fusion sheet 7 is inserted into the peripheral portion, the welding portion 5 is fitted in the notch portion 11. Therefore, positioning of the heat-fusion sheet 7 is performed more reliably and more easily.

  Further, by performing the above-described third process in this state, the notch 11 fitted to the end of the weld 5 is also melted around the end of the weld 5. Therefore, the joining length at the end of the weld 5 can be made longer, and the sealability of the heat seal portion 6 with the end of the weld 5 is further improved. As described above, in the present embodiment, in order to perform positioning of the heat-fusion sheet 7 more reliably and easily, and to further enhance the sealability of the portion of the heat seal portion 6 in contact with the weld portion 5, The cutaway portion 11 may be provided in the fusion sheet 7.

  Alternatively, the heat fusion sheet 7 may not have the slit portion 9. In this case, the electrode portion 4 may be inserted into the battery chamber 2 by breaking the heat fusion sheet 7 inserted into the peripheral portion of the metal foil. Alternatively, the heat fusible sheet 7 is bent in both sides of the electrode portion 4 in the stacking direction, ie, between the peripheral portion of the metal foil and the electrode portion 4 in the thickness direction of the battery exterior material 1. It may be pinched.

[Summary]
The battery exterior material according to the present embodiment is disposed in at least a part of a battery chamber for housing a battery element, which is formed of a joined metal foil, and around the battery chamber. And a flange portion formed by bonding. The flange portion is a heat seal formed by joining the metal foil by heat fusion of a weld formed by welding the metal foil and a heat fusion sheet disposed between the metal foil. Including the department. The heat fusion sheet is disposed between the metal foils in a bent state.

  Further, in the method of manufacturing the battery exterior material according to the present embodiment, a step of welding a part of the peripheral portion of the metal foil to form an internal space to be a battery chamber for accommodating the battery element, and the peripheral edge And a step of sandwiching the folded heat-fusion sheet in the remaining part of the part, and a step of heating the remaining part of the peripheral portion to heat-fuse the heat-fusion sheet and heat-sealing.

  Moreover, the battery which concerns on this Embodiment has the battery exterior material of this Embodiment, and the said battery element accommodated in the said battery chamber.

  Further, the method of manufacturing a battery according to the present embodiment further includes the step of housing the battery element in the internal space, in addition to the above-described steps in the method of manufacturing the battery exterior material of the present embodiment.

  According to the present embodiment, the battery exterior material by joining the metal foils is formed by the seal by welding and the seal by heat sealing of the resin, and the heat fusion sheet for heat sealing is at a desired position. Be placed securely and quickly. Therefore, according to the present embodiment, both space saving and reduction of manufacturing time can be realized in the battery exterior material and the battery.

  In the battery exterior material, the heat fusion sheet is opened along the fold line of the bent portion in the bent state, and an electrode portion for electrically connecting the battery element to the outside of the battery chamber is inserted. The heat seal part may further include a slit part for heat sealing of the heat fusion sheet in which the electrode part is inserted in the slit part. Further, in the above-mentioned manufacturing method, an electrode for electrically connecting the battery element with the outside of the battery chamber, which is opened along the fold line of the bent portion in the bent state in the heat fusion sheet The heat fusion sheet having a slit part for inserting a part may be inserted into the slit part in the step of sandwiching the heat fusion sheet.

  According to such a configuration, the heat fusible sheet can be bent more reliably and easily. In addition, the heat fusion sheet can be positioned more reliably and easily when the heat fusion sheet is disposed between the metal foils during heat sealing. Therefore, the above configuration is more effective from the viewpoint of shortening the manufacturing time and securing the sealing property.

  Further, in the step of sandwiching the heat fusible sheet, the ridge line of the bent portion of the heat fusible sheet being folded is directed toward the back of the peripheral edge, and the bent portion abuts on the welded portion of the peripheral edge The heat fusion sheet may be inserted into the remaining part of the peripheral portion.

  According to such a configuration, since the heat fusible sheet is inserted between the metal foils with the bent portion at the top, the heat fusible sheet is likely to be smoothly disposed at the desired position between the metal foils without being curled up . Therefore, it is more effective from the viewpoint of shortening of manufacturing time and securing of sealing property.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

Example 1
A SUS foil outer wrapping material which is a stretched product was manufactured by press-forming a SUS304 BA material having a thickness of 40 μm and a size of 200 mm × 100 mm square. The said SUS foil outer packaging material is comprised by the rectangular shaping | molding part and the flange part around it, when it planarly views. The above-mentioned press forming conditions are that punch R is 1 mm and die R is 1 mm, the size of the forming part is 3 mm in height, 180 mm × 90 mm in size in plan view, and 3 mm in corner R . As for the dimensions of the flange portion, the projection length of the portion along both long sides of the molding portion and the portion along one short side is 5 mm, and the projection length of the portion along the remaining short side is 15 mm.

  The two sheets of the SUS foil outer packaging material were put together so that the recesses formed by the formed parts faced each other. The battery element covered and insulated with a film was housed in a state of being attached with an electrode terminal (electrode portion) in a forming portion to be a battery chamber of the two SUS foil outer packaging materials. The battery element includes a stacked positive electrode, a negative electrode, and a separator. The electrode portion is connected to each of the positive electrode and the negative electrode. The electrode portion is an elongated rectangular aluminum plate-like member having a thickness of about 0.4 mm, and is disposed so as to extend outside the battery chamber through a portion with a projecting length of 15 mm in the flange portion.

  Next, of the portion with a projection length of 5 mm of the flange portion, a portion along the longitudinal direction of the formed portion was welded along the longitudinal direction at a position of 3 mm from the tip end edge of the flange portion. The position of the weld in the longitudinal direction is from the protruding end of the portion with a protruding length of 5 mm in the flange portion to the position 13 mm inside from the protruding end of the portion with a protruding length of 15 mm. Next, of the portion with a projection length of 5 mm in the flange portion, a portion along the short direction of the formed portion was welded along the short direction at a position of 3 mm from the tip end edge of the flange portion. The position of the weld in the short direction is a position intersecting the two welds in the longitudinal direction, that is, from the outside of one weld in the longitudinal direction to the outside of the other weld. In this manner, the welded portion was formed in the portion where the electrode portion in the flange portion is not disposed.

  The weld was formed by seam welding. FIG. 7 is a view schematically showing the configuration of the seam welding apparatus. The seam welding apparatus has a first electrode 130 and a second electrode 140 as shown in FIG. The first electrode 130 is a standing plate-like electrode, and the tip edge (one side edge) is rounded. The first electrode 130 has a thickness of 4 mm, a height of 50 mm, a length of 250 mm, and a rounded curvature of 20 R. The second electrode 140 is a rotatable disk-like electrode and has a diameter of 100 mm and a thickness of 4 mm. The seam welding was performed under the conditions of 150 N pressure, 1 m / min welding speed, 1.6 kA welding current, and 195 mm distance between electrodes (W in the figure).

  On the other hand, a slit portion is formed on a 100 mm × 52 mm × 0.1 mm thick polyolefin heat seal film (manufactured by Dainippon Printing Co., Ltd.) as shown in FIG. It bend | folded by the centerline containing a slit part as shown to be. And the obtained heat-fusion sheet | seat was inserted until the protrusion end in a flange part abuts on the end of two welds from the part of 15 mm, as shown to (a) of FIG. In the heat fusion sheet insertion, the electrode part extending from the battery chamber was inserted into the slit part of the heat fusion sheet, and the electrode part was sandwiched by the heat fusion sheet. Then, the electrode portion and the heat-fusion sheet were sandwiched by the remaining portion of the flange portion, and the portion was pressed by a heat sealer at 190 ° C. for 10 seconds and joined by heat sealing. Thus, a battery was obtained (see FIG. 1).

[Evaluation experiment 1]
In order to evaluate the sealing property of the junction in the above-mentioned battery, two kinds of samples A and B as shown in (a) and (b) of FIG. 8 were produced. (A) of FIG. 8 is a figure which shows typically the structure of the sample A in the evaluation experiment 1, and (b) of FIG. 8 is a figure which shows the structure of the sample B in the evaluation experiment 1 typically.

  In the sample A, as shown in FIG. 8A, the two long sides of the SUS foil outer wrapping material 12 and the three sides of one short side are welded at a welded portion 5 by seam welding. As shown in (b) of FIG. 8, in sample B, the two long sides of the SUS foil outer wrapping material 12 are welded at the welded portion 5 by seam welding, and one short side is the above-mentioned heat fusion It is joined by the heat seal part 6 by the heat seal which intervenes a sheet. The heat seal portion 6 is sealed in a state in which the electrode portion 4 is sandwiched.

  Ten samples A and B were prepared. Then, for each sample, a heat seal checker (made by Itinen Chemicals Co., Ltd.) of red liquid is sprayed from the inside of the weld and the heat seal toward the joint from the unwelded opening 13 to the joint without any leakage. It confirmed visually. As a result, no liquid leakage was observed in all the samples, and it was confirmed that sufficient sealing was maintained in any of the samples.

[Evaluation experiment 2]
A total of two sheets of the heat fusion sheet (100 mm × 26 mm) are inserted in each of the portions between the SUS foil and the electrode portion in the flange portion to be the heat seal portion, and the electrode portion and the SUS foil Heat sealed. At that time, the working time from the start of insertion of the heat fusible sheet to the start of heat sealing (the time for completing the insertion and placement of the heat fusible sheet) was measured. The working time was 12 seconds on average. In the above-mentioned operation, after inserting each heat fusion sheet on both sides of the electrode, it was necessary to make a fine adjustment so that there is no positional deviation.

  On the other hand, the working time from the insertion of the heat-fusion sheet in Example 1 to the start of heat sealing was 6 seconds on average including the bending work.

  The following three points can be mentioned as reasons for the short working time in the first embodiment. First, since the slit portion is formed in advance in the heat-fusion sheet, the heat-fusion sheet can be easily bent along the weak slit portion. Second, when the slit portion of the folded heat-fusion sheet (the above-mentioned heat-fusion sheet) is inserted into the electrode part, the heat-fusion sheet does not fall off during the operation. And thirdly, in order to insert the electrode portion into the slit portion, the positional deviation of the heat fusion sheets overlapping with the electrode portion does not occur. Therefore, the heat fusible sheet is disposed at the desired position only by pressing the heat fusible sheet against the end of the welded portion. For this reason, in Example 1, it does not take time for fine adjustment of the position of heat sealing | fusion sheet | seats.

  From the above description, Example 1 inserts and arranges the heat fusible sheet in a short time in an accurate position as compared with the case where the heat fusible sheet is individually inserted between the electrode portion and the metal foil respectively. It turns out that you can do it. Therefore, according to the present invention, the heat fusible sheet (heat fusible sheet) is disposed at a desired position with high accuracy and in a short time without requiring skill, as compared to the case where individual heat fusible sheets are inserted. be able to. Further, in the present invention, an effect of preventing a decrease in yield due to a heat seal failure is also expected.

  The present invention can be suitably used for secondary batteries such as lithium ion batteries. Further, the present invention can be used for a bonding structure of a metal foil including a welded portion and a heat seal portion and including a member which is sandwiched and sealed by the heat seal portion.

DESCRIPTION OF SYMBOLS 1 battery exterior material 2 battery chamber 3 flange part 4 electrode part 5 welding part 6 heat sealing part 7 heat sealing sheet 9 slit part 11 notch part 10 battery element 12 SUS foil outer packaging material 13 opening part 100 battery 130 1st electrode 140 Second electrode

Claims (8)

A battery compartment, formed by joined metal foils, for housing battery elements;
And a flange portion disposed at least at a portion of the periphery of the battery chamber and formed by bonding of the metal foils,
The flange portion is a heat seal formed by joining the metal foil by heat fusion of a weld formed by welding of the metal foil and a heat fusion sheet disposed between the metal foil. Part, and
The heat fusion sheet is disposed between the metal foils in a bent state.
Battery exterior material. The heat fusion sheet further includes a slit portion which is opened along the fold line of the bent portion in the bent state and which passes through an electrode portion for electrically connecting the battery element to the outside of the battery chamber. Including
The heat seal part is formed by heat fusion of the heat fusion sheet in which the electrode part is inserted in the slit part.
The battery exterior material according to claim 1.   The battery sheathing material according to claim 1 or 2, wherein the heat fusion sheet is disposed such that a ridge line formed by bending is positioned at the back of the flange portion.   The battery which has a battery exterior material as described in any one of Claims 1-3, and the said battery element accommodated in the said battery chamber. A step of welding a part of the peripheral portion of the metal foil to form an internal space serving as a battery chamber for housing the battery element;
Sandwiching a folded heat-fusion sheet in the remaining part of the peripheral portion;
And heating the remaining portion of the peripheral portion to heat-seal the heat-fusion sheet for heat-sealing. The heat fusion sheet has a slit portion which is opened along a fold line of a bent portion in a bent state, and which is for inserting an electrode portion for electrically connecting the battery element to the outside of the battery chamber Using a heat fusion sheet having
The manufacturing method of the battery exterior material of Claim 5 which makes the said slit part penetrate the said electrode part in the process of pinching | interposing the said heat sealing | fusion sheet | seat.   In the step of sandwiching the heat fusible sheet, the ridge line of the bent portion in the folded heat fusible sheet is directed to the back of the peripheral edge until the bent portion abuts on the welded portion of the peripheral edge. The manufacturing method of the battery exterior material of Claim 5 or 6 which inserts a heat sealing | fusion sheet | seat in the remaining part of the said peripheral part.   The method for manufacturing a battery according to any one of claims 5 to 7, further comprising the step of housing the battery element in the internal space.

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