JP4069885B2 - Film exterior battery manufacturing apparatus and film exterior battery manufacturing method - Google Patents

Description

  The present invention relates to a film-clad battery in which battery elements are housed in a packaging material made of a film, and a stacked assembled battery in which a plurality of film-clad batteries are stacked in the thickness direction of the battery element.

  Conventionally, as a film-clad battery using a heat-sealable film as a packaging material, a battery element is surrounded by a laminate film in which a metal layer and a heat-sealable resin layer are laminated, and a positive electrode connected to the battery element and The battery element is hermetically sealed (hereinafter also simply referred to as “sealing”) by heat-sealing (sealing) the open edge of the laminate film with the negative electrode lead terminal pulled out from the laminate film. Things are known.

  FIG. 6 shows an exploded perspective view of a conventional film-covered battery using a heat-fusible film as a packaging material, and FIG. 7 shows a conventional heat-sealing method for the edge of a laminate film.

  The film-clad battery 101 includes a battery element 102, a positive electrode current collector 103 a and a negative electrode current collector 103 b provided on the battery element 102, and two laminate films 105 and 106 that store the battery element 102 together with an electrolytic solution. An outer package, a positive electrode tab 104a connected to the positive electrode current collector 103a, and a negative electrode tab 104b connected to the negative electrode current collector 103b.

  The battery element 102 is configured by alternately laminating a plurality of positive plates and a plurality of negative plates via separators.

  As a typical example of the two laminate films 105 and 106 that sandwich and surround the battery element 102 from both sides in the thickness direction, a heat-fusible resin having heat-fusibility on one side of the metal layer 111 that is an aluminum thin film. There is a three-layer laminate film in which the layer 110 is laminated and the protective film 112 is laminated on the other surface.

  The laminated films 105 and 106 of the film-clad battery 101 having such a structure are sealed by heat-sealing the heat-sealing portions 105a and 106a as shown in FIG.

  First, the battery element 102 is sandwiched from both sides in the thickness direction so that the heat-fusible resin layer 110 faces each other, and the two heaters 150 are arranged so that the heat-bonding portions 105a and 106a face the pressing surface 151. Place between. Next, the heater 150 is sandwiched from above and below (in the direction of arrow a) and heated while applying pressure. By this pressing and heating, the heat-fusible resin layer 110 of the heat-sealing portions 105a and 106a is melted and heat-sealed.

  When the heat-sealed part of the laminate film is sandwiched by a heater and heated while applying pressure, as shown in FIG. 8, the melted heat-fusible resin is transferred from the heat-fused part to the inside of the battery and the outside of the battery (not shown). The resin pool 160 is formed by protruding to the outside. After the heat fusion parts 105 a and 106 a are fused by the heater 150, the heat fusion parts 105 a and 106 a are fused to each other by separating the heater 150 from the laminate films 105 and 106 and solidifying by cooling. By sealing the peripheral portion of the battery by heat-sealing in this manner, it is possible to prevent leakage of the electrolytic solution from the inside of the battery.

In Patent Document 1, there is a manufacturing method in which a heat fusion is performed using a heater in which concave portions are formed in an upper die and a lower die for the purpose of improving adhesion by heat fusion, and a convex portion is formed in a heat fusion portion. It is disclosed.
JP 2001-229889 A

  However, when the heat fusion part is cooled and solidified in a state where the resin pool is formed, the following problems may occur.

  The linear expansion coefficient of the heat-fusible resin layer is larger than that of the metal layer that is an aluminum thin film. That is, since the shrinkage amount of the heat-fusible resin layer is larger than the shrinkage amount of the metal layer, when cooling and solidifying, as shown in FIG. The nearby heat-fusible resin layer 110 is also drawn toward the resin reservoir 160. Due to the drawing of the resin, a thin region 170 is formed in the heat-fusible resin layer in the vicinity of the resin reservoir, resulting in a problem that the insulation of the region 170 becomes lower than other regions. There is a case. In addition, a microcrack of the heat-fusible resin may occur at the location of the region 170. When this microcrack occurs, depending on its size, if it becomes large, the sealing performance is affected.

  In order to prevent the occurrence of the resin pool in the heat fusion part, it is necessary to prevent the flow of the molten resin from the heat fusion part. For example, a method is conceivable in which a concave portion is formed in the heater, a convex portion is formed in the laminate film at the concave portion, and the resin is stored in the convex portion.

  Patent Document 1 discloses a method of manufacturing a battery in which molten resin is stored in a recess provided in a portion where a protruding portion of a positive electrode and a negative electrode and a film are in contact with each other. The leakage of the electrolytic solution is prevented by improving the above, and there is no recognition of the problems of the deterioration of insulation and the occurrence of microcracks caused by the resin reservoir as described above. Therefore, no consideration has been given to the dimensions of the recesses necessary to prevent the resin pool.

  If the micro-crack generated in the thin region 170 in the heat-fusible resin layer near the resin reservoir formed by drawing the resin becomes larger than the limit, it may reach the metal layer. When the microcracks reach the metal layer, there is a risk that the electrolyte directly contacts the metal layer. When the electrolyte is in direct contact with the metal layer, the dissimilar metal is eluted from the metal layer into the electrolyte and deposited on the electrode surface. In the case of a lithium ion secondary battery, the eluted dissimilar metal is in the electrolyte. Since it is alloyed with lithium ions, corrosion may occur in the metal layer.

  Accordingly, the present invention provides a film-clad battery that can prevent the insulation from being reduced and the occurrence of microcracks by reducing the thickness of a part of the resin film in the cooling process after heat sealing. An object of the present invention is to provide a manufacturing apparatus and a film-clad battery manufacturing method.

In order to achieve the above object, the film-clad battery manufacturing apparatus of the present invention includes a battery element in which a plurality of positive plates and a plurality of negative plates are stacked facing each other, and at least a heat-fusible resin layer and a metal layer. A film-covered battery comprising: an outer package film that is laminated, surrounds the battery element with the heat-fusible resin layer inside, and has a peripheral joint portion heat-sealed to seal the battery element. In an apparatus for manufacturing a film-sheathed battery having a heater that is used for heat-sealing and heat-sealing by pressing and heating the joint portion with a pressing surface.
There is a recess for forming at least one protrusion on the outer body film for storing the resin of the heat-fusible resin layer to form a resin reservoir at an end of the joint on the side containing the battery element. Formed on the pressing surface of the heater ;
The amount of the heat-fusible resin layer that was melted to form a resin reservoir at the end portion on the side containing the battery element was crushed by pressing and heating the two exterior body films with the heater. In the surface including the thickness of the heat-fusible resin layer 2t, the pressing direction of the heater of the convex portion, and the direction from the side containing the battery element toward the outer edge side of the joint portion of the peripheral edge The sum of the cross-sectional areas is 2S, the initial thickness of the heat-fusible resin layer of the exterior body film is T, the width of the heater is W, and either the W direction or the pressing direction of the heater is the heater. When the depth in the vertical direction is L,
For D = (T−t) W · L,
2S ・ L> D
The convex portion is formed so as to satisfy the above condition .

  In the film-clad battery manufacturing apparatus of the present invention configured as described above, a concave portion for forming the convex portion on the outer package film is formed on the pressing surface of the heater. That is, since the convex part of the outer package film formed by the concave part of the heater can collect molten resin that flows from the center of the joint part toward the side containing the battery element to form a resin reservoir, It is possible to prevent a large resin reservoir from being formed on the side of the joint that encloses the battery element. Therefore, when the resin reservoir cools and solidifies, the amount of resin that draws the resin in the vicinity of the resin reservoir toward the resin reservoir can be reduced.

  In the film-clad battery manufacturing apparatus of the present invention, the amount of the molten heat-fusible resin layer to form a resin reservoir at the end portion on the side containing the battery element is D, and the cross-sectional area of the convex portion is 2S. When the depth of the heater is L, the resin flows from the center of the joint toward the side containing the battery element by forming the convex so that the concave satisfies 2S · L> D. All can be stored in the convex portion, which is preferable.

  In the film-clad battery manufacturing apparatus of the present invention, the distance from the heater inner surface to the recess, which is the surface on the side containing the battery element of the heater, is V, and the pressing surface between the heater inner surface and the recess is recessed from the pressing surface. The convex portion may be formed so that the concave portion satisfies 2S · L> D + d, where d is the amount of the melted heat-fusible resin layer flowing toward. In this case, the resin flowing from the heater inner surface toward the concave portion from the heater inner side surface at the position of V / 2 can be accumulated in the convex portion, so that the resin reservoir can be further reduced.

  Further, in the heater of the film-clad battery manufacturing apparatus of the present invention, the distance V from the heater inner surface, which is the surface that encloses the battery element of the heater, to the concave portion is a process of forming the concave portion while leaving the portion of the distance V. Difficulty, whether or not the portion of the distance V can withstand the stress at the time of pressing and heating the joint, and further, from the inner surface of the heater to the inner surface 53 of the heater 53 from the recess at the position of V / 2 In consideration of minimizing the resin pool due to the flow, it is preferable to set the amount within the range of 0.05 to 2 mm.

The film-clad battery manufacturing method of the present invention includes a battery element in which a plurality of positive plates and a plurality of negative plates are stacked to face each other, at least a heat-fusible resin layer, and a metal layer, In the method of manufacturing a film-clad battery, which has an adhesive resin layer on the inside, surrounds the battery element, and has an outer package film that seals the battery element by heat-sealing a peripheral joint.
A heater having a depression formed on the pressing surface, wherein the depression corresponds to a center of the joint portion in a direction from the side containing the battery element toward the outer edge side of the joint portion . Preparing the heater formed from the center to a position spaced by a distance V from the heater inner surface, which is a surface of the heater containing the battery element;
Pressurizing and heating the joint portion with the pressing surface of the heater, forming a convex portion on the exterior body film, and storing resin that is to form the resin reservoir in the convex portion; and
The amount of the heat-fusible resin layer that was melted to form a resin reservoir at the end portion on the side containing the battery element was crushed by pressing and heating the two exterior body films with the heater. The thickness of the heat-fusible resin layer is 2t, and the surface of the convex portion includes the pressing direction of the heater and the direction from the side where the battery element is contained toward the outer edge side of the peripheral edge joining portion. The sum of the cross-sectional areas is 2S, the initial thickness of the heat-fusible resin layer of the exterior body film is T, the width of the heater is W, and either the W direction or the heater pressing direction of the heater. When the depth in the vertical direction is L,
For D = (T−t) W · L,
2S ・ L> D
Forming the convex portion so as to satisfy the above condition .

  In addition, according to the method for manufacturing a film-clad battery of the present invention, the amount of the molten heat-fusible resin layer to form a resin reservoir at the end portion on the side containing the battery element is D, and the cross-sectional area of the convex portion is 2S. When the depth of the heater is L, the convex portion may be formed by the concave portion so as to satisfy 2S · L> D.

  In the method for manufacturing a film-clad battery according to the present invention, the distance from the heater inner surface to the recess, which is the surface on the side containing the battery element of the heater, is V, and the pressing surface between the heater inner surface and the recess is recessed from the pressing surface. If the amount of the melted heat-fusible resin layer flowing toward the surface is d, a convex portion may be formed by the concave portion so as to satisfy 2S · L> D + d.

  According to the present invention, a convex portion can be formed on the exterior body film by the concave portion of the heater, and the molten resin can be stored in the convex portion, so that a large resin reservoir is formed on the side of the joint portion including the battery element. Can be prevented. As a result, the amount of resin that draws in the resin of the nearby heat-fusible resin layer when the resin is solidified by cooling can be reduced, so that the heat-fusible resin layer does not become thin and prevents deterioration of insulation. And generation of microcracks can be prevented. Furthermore, the adhesive strength can be improved by the resin accumulated in the convex portions.

  FIG. 1 is an exploded perspective view of the film-clad battery according to the present embodiment.

  The film-clad battery 1 includes a battery element 2, a positive electrode current collector 3a and a negative electrode current collector 3b provided in the battery element 2, and two laminated films 5 and 6 that store the battery element 2 together with an electrolyte. An outer casing, a positive electrode tab 4a connected to the positive electrode current collector 3a, and a negative electrode tab 4b connected to the negative electrode current collector 3b.

  The battery element 2 is configured by alternately laminating a plurality of positive plates and a plurality of negative plates via separators.

  Each positive plate has a positive electrode applied to an aluminum foil, a negative electrode has a negative electrode applied to a copper foil, and extends from the laminated region. The extensions and the extensions of the negative electrode plate are ultrasonically welded together to form the positive electrode current collector 3a and the negative electrode current collector 3b, which are relay parts. At the same time, the welding of the positive electrode tab 4a to the positive electrode current collector 3a and the connection of the negative electrode tab 4b to the negative electrode current collector 3b are also ultrasonically welded.

  The exterior body is composed of two laminated films 5 and 6 that surround and surround the battery element 2 from both sides in the thickness direction. Each of the laminate films 5 and 6 is formed by laminating a heat-fusible resin layer 10 having heat-fusibility, a metal layer 11, and a protective layer 12 (see FIG. 5 and the like), and is made of PP (polypropylene). The battery element 2 is sealed by heat-sealing the heat-sealing portions 7 of the laminate films 5 and 6 so that the heat-fusible resin layer 10 to be the inner layer of the battery.

  As the laminate films 5 and 6, as long as the battery element 2 can be sealed so that the electrolytic solution does not leak, a film used for this type of film-clad battery can be used. A laminate film in which a layer and a heat-fusible resin layer are laminated is used. As this type of laminate film, for example, a film obtained by attaching a heat-fusible resin having a thickness of 3 μm to 200 μm to a metal foil having a thickness of 10 μm to 100 μm can be used. As the material of the metal foil, that is, the metal layer 11, Al, Ti, Ti-based alloy, Fe, stainless steel, Mg-based alloy, or the like can be used. As the heat-fusible resin, that is, the heat-fusible resin layer 10, polypropylene, polyethylene, acid-modified products thereof, polyester such as polyphenylene sulfide, polyethylene terephthalate, etc., polyamide, ethylene-vinyl acetate copolymer, etc. are used. it can. Further, as the protective layer 12, nylon or the like is suitable.

  FIG. 2 is a side cross-sectional view of a heater for heat-sealing a heat-sealing portion of a laminate film in a film-clad battery manufacturing apparatus.

  In the film-clad battery manufacturing apparatus of this embodiment, the two heaters 50 are movably movable in the direction of arrow A with the pressing surfaces 51 facing each other. The heat fusion of the heat fusion part 7 of the laminate films 5 and 6 is performed by sandwiching the heat fusion part 7 between the heaters 50 and pressing and heating. The heat-sealed portion 7 of the laminate films 5 and 6 is disposed on the inner surface 53 side of the heater 50 on the side where the battery element 2 of the film-clad battery 1 is enclosed, and on the outer surface 54 side on the outer edge side of the heat-fused portion 7. Is placed.

  A concave portion 52 is formed on the pressing surface 51 of each of the heaters 50 on the inner surface 53 side of the center line of the heater 50. That is, the recess 52 is formed at a position spaced from the inner surface 53 of the pressing surface 51 by a distance V.

  The dimensions of the recess 52 formed in the heater 50 are determined by the following procedure. This determination procedure will be described with reference to the model diagrams of FIGS. In each figure, the metal layer 11 and the protective layer 12 of the laminate films 5 and 6 are collectively shown in order to make it easier to understand the flow state of the heat-fusible resin layer that is pressed and heated between the heaters. It is shown as one line, and only the region where the heat-fusible resin layer is sandwiched between the heaters is shown. Furthermore, the resin pool extruded by pressure heating is described as an independent mass.

  First, the flow state of the resin at the peripheral edge of the laminate film when it is pressed and heated by a heater in which no recess is formed will be described with reference to the schematic diagram shown in FIG.

  Here, the initial thickness of one of the heat-fusible resin layers 10 of the laminate films 5 and 6 is T, and the thickness after being crushed by heat-sealing is t. Further, the width of the heater 50a in which no recess is formed is W, and the depth of the heater 50a is L (not shown).

  By laminating the two laminate films 5 and 6, the thickness of the heat-fusible resin layer 10 becomes 2T (FIG. 3A).

The heat-fusible resin layer 10 in a region sandwiched between the heaters 50a having a width W is melted by placing the heat-fusible resin layer 10 having a thickness of 2T between the heaters 50a and pressing and heating the heater 50a from above and below. Then, it is crushed to a thickness of 2t (FIG. 3B). Therefore, the crushing amount P of the resin is
P = (2T-2t) W · L (1)
It becomes. Here, the heat-sealable resin layer 10 corresponding to the crushed portion, that is, the resin having a crushed amount P, is extruded in half in the direction of the inner side 53a and the direction of the outer side 54a with the center line B as a boundary. If the reservoirs 60a1 and 60a2 are to be formed, the respective reservoir amounts D of the resin reservoirs 60a1 and 60a2 formed on both sides of the heat-sealed region are respectively
D = P / 2 = (T−t) W · L (2)
It will be expressed as

  Next, the flow state of the resin at the peripheral edge of the laminate film when it is pressed and heated by the heater 50 in which the recess 52 is formed will be described with reference to the schematic diagram shown in FIG. Note that the width of the recess 52 and the distance V from the inner side surface 53 to the recess 52 are sufficiently smaller than the width W of the heater 50.

  By laminating the two laminate films 5 and 6, the thickness of the heat-fusible resin layer 10 becomes 2T (FIG. 4A).

  The heat-fusible resin layer 10 in a region sandwiched between the heaters 50 having a width W is melted by placing the heat-fusible resin layer 10 having a thickness of 2T between the heaters 50 and pressing and heating the heater 50 from above and below. Then, it is crushed to a thickness of 2t (FIG. 4B). At this time, the crushing amount P of the resin is expressed by the equation (1) as in the case where the resin is pressed and heated by the heater in which no concave portion is formed, and P = (2T−2t) W · L. The amount of resin flowing out on both sides of the heat-sealed region of the heater 50 is that the recess 50 is formed in the heater 50, so that the resin reservoir 60 ′ formed on the inner surface 53 and the resin reservoir formed on the outer surface 54. 60 and the amount is different.

  That is, since the concave portion 52 is formed in the heater 50, the convex portions 5a and 6a are formed by sandwiching the heat fusion portion 7 of the laminate films 5 and 6 with the heater 50 and pressing and heating the convex portions 5a and 6a, respectively. , 6a enters the heat-fusible resin layer 10 flowing from the center line c toward the inner surface 53. For this reason, the amount of the resin reservoir 60 ′ formed on the inner surface 53 is different from that of the resin reservoir 60 formed on the outer surface 54.

Here, the sum of the cross-sectional areas of the convex portions 5a, 6a is 2S,
2S · L> D (3)
As a result, it is possible to prevent the heat-fusible resin layer 10 flowing from the center line C toward the inner side surface 53 from becoming a resin pool inside the battery. That is, the amount D of the heat-fusible resin layer flowing from the center line C toward the inner side surface 53 by allowing the cross-sectional areas S of the convex portions 5a and 6a formed in the concave portion 52 to satisfy the expression (3). 10 can be received in the two convex portions 5a and 6a, and can be heat-sealed without producing a resin reservoir 60 'inside the battery.

  In the above handling, the distance V is sufficiently smaller than the width W of the heater 50 for the heat-fusible resin layer 10 crushed between the inner side surface 53 and the recess 52 (part of the distance V). However, when the heat-sealable resin layer 10 crushed in the portion of the distance V is also considered, it is as follows.

That is, in the heat-sealable resin layer 10 crushed at the distance V, the flow from the inner side surface 53 toward the concave portion 52 from the inner side surface 53 to the V / 2 position flows into the convex portions 5a and 6a. On the contrary, the flow from the recess 52 toward the inner surface 53 becomes a resin reservoir 60 '. The amount d accumulated as the resin reservoir 60 ′ and the amount d of the resin flowing into the recess 52 are respectively handled in the same manner as described above, so that d = (T−t) V · L (4)
It becomes. Therefore, when this amount d is also taken into consideration,
2S · L> D + d (5)
Is preferable.

  The distance V from the inner surface 53 to the recess 52 is the degree of difficulty in forming the recess 52 while leaving the distance V, and the stress when the distance V presses and heats the heat-sealed portion 7. In consideration of whether the strength sufficient to withstand the pressure can be secured, and further, the amount of the resin reservoir 60 'due to the flow from the concave portion 52 to the inner side surface 53 from the inner side surface 53 as a boundary is reduced as much as possible. It is preferable to set it in the range of 0.05 to 2 mm. That is, when the distance V is 0.05 mm or less, the resin reservoir 60 ′ can be reduced, but it is difficult to form the concave portion 52 while leaving the portion of the distance V by grinding, and it can be formed. However, the stress at the time of heat-pressing the heat-sealing part 7 cannot be withstood, and there is a possibility that the part of the distance V will be crushed. On the other hand, if the distance V is 2 mm, on the contrary, the grinding process becomes easy and the distance V portion can be made difficult to be crushed, but it is pushed out by the distance V portion toward the inner side surface 53. The resin increases, and the resin reservoir 60 'becomes large. Therefore, it is preferable to form the portion of the distance V within a range of 0.05 to 2 mm.

  Next, FIG. 5 shows a partially enlarged cross-sectional view of the heat-sealed portion 7 of the laminate films 5 and 6 heat-sealed by the heater 50 in which the concave portion 52 is formed in this embodiment.

  Resin protrusions 10a are formed by the heat-sealable resin layer 10 flowing into the protrusions 5a, 6a of the heat-bonding part 7, thereby making it possible to reduce the resin reservoir 60 'inside the battery.

  Although the linear expansion coefficient of the heat-fusible resin layer 10 is larger than that of the metal layer 11 that is an aluminum thin film, since the formed resin reservoir 60 ′ is small, the shrinkage of the resin reservoir 60 ′ during the cooling process after press heating is reduced. It stays within the contraction range indicated by the broken line in the figure. That is, the amount of shrinkage of the resin reservoir 60 ′ is very small as compared with the case where the conventional large resin reservoir contracts. Therefore, the resin reservoir 60 ′ reaches the heat-fusible resin layer 10 in the vicinity of the resin reservoir 60 ′. The amount of drawing can be reduced. As a result, it is possible to prevent the heat-fusible resin layer 10 in the vicinity of the resin reservoir 60 'from being thinned, and thus it is possible to prevent the insulation from deteriorating and to generate microcracks. Can be prevented.

  Moreover, since the resin convex part 10a is formed, the amount of resin contributing to the thermal fusion in the thermal fusion part 7 can be increased and the adhesive strength can be improved.

  In the present embodiment, an example is shown in which one recess 52 is formed in each heater 50. However, the present invention is not limited to this, and a plurality of recesses are formed in each heater 50. It may be. Further, the position where the recess 52 is formed may be formed not only on the inner surface 53 side from the center line C but also on the outer surface 54 side from the center line C. In addition, when a plurality of recesses are formed, the above-described sum 2S of cross-sectional areas may be any as long as the sum of the cross-sectional areas of the respective recesses satisfies the formula (3) or (5). The individual sizes need not all be the same.

Further, in the present embodiment, an example is shown in which one recess 52 is formed in each of the heaters 50 arranged opposite to each other, but the recess 52 is formed only in one of the opposing heaters 50. It may be a thing.
In this case, the total cross-sectional area 2S described above may have the cross-sectional area S of each of the convex portions 5a and 6a, or the recess 52 having a cross-sectional area of 2S is formed in only one of the two heaters 50. You may do.

  As mentioned above, although typical embodiment of this invention was described, it supplements about the structure of each part of a film-clad battery below.

(Lead terminal)
The lead terminal can be made of Al, Cu, Ni, Ti, Fe, phosphor bronze, brass, stainless steel, or the like, and may be annealed as necessary. The thickness of the lead terminal is preferably 0.08 to 1.0 mm.

  Moreover, it is also preferable to perform a surface treatment for improving adhesion to the exterior material on at least a portion of the lead terminal that is in close contact with the exterior material. As this type of surface treatment, for example, roughening treatment by chemical etching treatment, etc., corrosion-resistant film ground treatment by a partially aminated phenolic polymer, a phosphoric acid compound and a titanium compound film or a zinc phosphate-based film, Examples thereof include surface treatment with a titanium coupling agent or an aluminate coupling agent.

  It is preferable that a resin film containing a metal adhesive resin is previously fused to the lead terminal. As the metal-adhesive resin, one that adheres to the surface of the lead terminal, which is a metal flat plate, is used. For example, acid-modified polypropylene, acid-modified polyethylene, acid-modified poly (ethylene-propylene) copolymer, ionomer, etc. can be used. .

(Exterior material)
The exterior material is not particularly limited as long as it can cover the battery element so that the electrolyte does not leak and has flexibility, but the metal layer and the heat-fusible resin layer A laminated film laminated is particularly preferably used. As this type of laminate film, for example, a film obtained by attaching a heat-fusible resin having a thickness of 3 μm to 200 μm to a metal foil having a thickness of 10 μm to 100 μm can be used. As a material of the metal foil, Al, Ti, Ti-based alloy, Fe, stainless steel, Mg-based alloy, or the like can be used. As the heat-fusible resin, polypropylene, polyethylene, acid modified products thereof, polyphenylene sulfide, polyester such as polyethylene terephthalate, polyamide, ethylene-vinyl acetate copolymer, and the like can be used.

(Battery element)
The battery element may be a laminated type or a wound type as long as it has a structure in which positive plates and negative plates are alternately laminated via separators. In the stacked type, a plurality of positive electrode plates and negative electrode plates are alternately stacked with separators interposed therebetween, and tabs extending from the positive electrode plates and the negative electrode plates are collected for each positive electrode plate and negative electrode plate as current collectors. Are respectively connected to the lead terminals. In the winding type, a positive electrode plate, a negative electrode plate, and a separator are formed in a strip shape, stacked, and then wound, further compressed into a flat shape, and tabs extending from the positive electrode plate and the negative electrode plate are respectively used as lead terminals. It is connected.

  Among these stacked types and wound types, the advantages of the present invention can be utilized particularly by using a stacked battery element. The reason for this is that the heat escapes directly from the lead terminal to each positive electrode plate (negative electrode plate) via the current collector, so that the lead terminal is not attached when the exterior material is heat-sealed at the portion where the lead terminal is drawn out. It is hard to warm up.

The positive electrode plate is not particularly limited as long as it absorbs positive ions or discharges negative ions during discharge, and (i) a metal oxide such as LiMnO ₂ , LiMn ₂ O ₄ , LiCoO ₂ , LiNiO ₂ , ( ii) conductive polymers such as polyacetylene and polyaniline, (iii) general formula (R-Sm) n (R is aliphatic or aromatic, S is sulfur, m and n are m ≧ 1, n ≧ 1 As a positive electrode material of a secondary battery such as a disulfide compound (dithioglycol, 2,5-dimercapto-1,3,4-thiadiazole, S-triazine-2,4,6-trithiol, etc.) represented by A conventionally well-known thing can be used. Further, a positive electrode active material (not shown) can be mixed with an appropriate binder or functional material on the positive electrode plate. Examples of these binders include halogen-containing polymers such as polyvinylidene fluoride, and functional materials include conductive polymers such as acetylene black, polypyrrole, and polyaniline for ensuring electron conductivity, ion conductivity. For example, a polymer electrolyte, a complex thereof, and the like.

  The negative electrode plate is not particularly limited as long as it is a material capable of occluding and releasing cations. Natural graphite, crystalline carbon such as graphitized carbon obtained by heat treatment of coal / petroleum pitch at high temperature, coal, petroleum pitch coke Conventionally known negative electrode active materials for secondary batteries such as amorphous carbon obtained by heat treatment of acetylene pitch coke and the like, lithium alloys such as metallic lithium and AlLi can be used.

Examples of the electrolyte solution impregnated in the battery element include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, N, N′-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, m - a cresol, a highly basic solvent of available polar as an electrolyte of a secondary battery, Li or K, an alkali metal cation and ClO such as Na _{^{4 -, BF 4 -, PF}} 6 -, CF 3 SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , (C ₂ F ₅ SO ₂ ) ₃ C ^{− and the} like What melt | dissolved the salt which consists of the anion of the compound to contain is mentioned. Moreover, the solvent and electrolyte salt which consist of these basic solvents can also be used individually or in combination. Moreover, it is good also as a gel electrolyte made into the polymer gel containing electrolyte solution. A small amount of sulfolane, dioxane, dioxolane, 1,3-propane sultone, tetrahydrofuran, vinylene carbonate, or the like may be added.

  The above is a material system as a lithium ion secondary battery, but the present invention can also be applied to a lead battery, a nickel cadmium battery, and a nickel metal hydride battery. The present invention can be applied not only to batteries but also to electric double layer capacitors, non-aqueous electrolyte capacitors, and the like.

It is a disassembled perspective view of the film-clad battery by one Embodiment of this invention. It is a sectional side view of the heater of the manufacturing apparatus of the film-clad battery of this invention. It is a schematic diagram which shows the flow condition of the resin in the peripheral part of a laminate film when it is pressed and heated by the heater in which the recessed part is not formed. It is a schematic diagram which shows the flow condition of the resin in the peripheral part of a laminate film at the time of being pressed and heated with the heater of this embodiment in which the recessed part is formed. It is a partial expanded sectional view of the heat fusion part of the laminate film heat-sealed by the heater in which the recessed part was formed. It is a disassembled perspective view of the film exterior battery which used the conventional heat-fusible film as an exterior material. It is a schematic diagram which shows the flow condition of resin in the peripheral part of a laminate film when it is pressed and heated by a conventional heater. It is a schematic diagram which shows the resin reservoir formed in the battery inner side of the heat-fusion part. It is a schematic diagram which shows the state in which the area | region with low insulation was formed by drawing of resin.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film exterior battery 2 Battery element 3a Positive electrode current collection part 3b Negative electrode current collection part 4a Positive electrode tab 4b Negative electrode tab 5, 6 Laminate film 5a Convex part 7 Thermal fusion part 10 Thermal fusion resin layer 10a Resin convex part 11 Metal layer 12 Protective layer 50, 50a Heater 51 Press surface 52 Recess 53, 53a Inner side surface 53 Inner side surface 54, 54a Outer side surface

Claims (5)

A battery element in which a plurality of positive plates and a plurality of negative plates are stacked facing each other, and at least a heat-fusible resin layer and a metal layer are laminated, and the battery element has the heat-fusible resin layer inside. And pressurizing and heating the joint with a pressing surface used for heat fusion of a film-clad battery having an outer body film that seals the battery element by heat-sealing the peripheral joint. In an apparatus for manufacturing a film-sheathed battery having a heater that is heat-sealed with
There is a recess for forming at least one protrusion on the outer body film for storing the resin of the heat-fusible resin layer to form a resin reservoir at an end of the joint on the side containing the battery element. Formed on the pressing surface of the heater ;
The amount of the heat-fusible resin layer that was melted to form a resin reservoir at the end portion on the side containing the battery element was crushed by pressing and heating the two exterior body films with the heater. The thickness of the heat-fusible resin layer is 2t, and the surface of the convex portion includes the pressing direction of the heater and the direction from the side where the battery element is contained toward the outer edge side of the peripheral edge joining portion. The sum of the cross-sectional areas is 2S, the initial thickness of the heat-fusible resin layer of the exterior body film is T, the width of the heater is W, and either the W direction or the heater pressing direction of the heater. When the depth in the vertical direction is L,
For D = (T−t) W · L,
2S ・ L> D
The said convex part is formed so that it may satisfy | fill , The manufacturing apparatus of the film-clad battery characterized by the above-mentioned . The distance from the inner surface of the heater, which is the surface of the heater that encloses the battery element, to the recess is V, and the molten material that flows into the recess from the pressing surface between the heater inner surface and the recess. When the amount of the heat-fusible resin layer is d, with respect to d = (T−t) V · L, the concave portion is
2S · L> D + d
The apparatus for producing a film-clad battery according to claim 1, wherein the convex portion is formed so as to satisfy the above condition. The distance V is in a range of 0.05 to 2 mm, where V is a distance from an inner surface of the heater, which is a surface of the heater including the battery element, to the recess. The manufacturing apparatus of the film-clad battery of description. A battery element in which a plurality of positive plates and a plurality of negative plates are stacked facing each other, and at least a heat-fusible resin layer and a metal layer are laminated, and the battery element has the heat-fusible resin layer inside. In a method for manufacturing a film-clad battery having an exterior body film that seals the battery element by heat-sealing the peripheral joints,
A heater having a depression formed on the pressing surface, wherein the depression corresponds to a center of the joint portion in a direction from the side containing the battery element toward the outer edge side of the joint portion . Preparing the heater formed from the center to a position spaced by a distance V from the heater inner surface, which is a surface of the heater containing the battery element;
Pressurizing and heating the joint portion with the pressing surface of the heater, forming a convex portion on the exterior body film, and storing resin that is to form the resin reservoir in the convex portion; and
The amount of the heat-fusible resin layer melted to form a resin reservoir at the end portion on the side containing the battery element was crushed by pressing and heating the two exterior body films with the heater. The thickness of the heat-fusible resin layer is 2t, and the surface of the convex portion includes the pressing direction of the heater and the direction from the side where the battery element is contained toward the outer edge side of the peripheral edge joining portion. The sum of the cross-sectional areas is 2S, the initial thickness of the heat-fusible resin layer of the exterior body film is T, the width of the heater is W, and either the W direction or the heater pressing direction of the heater. When the depth in the vertical direction is L,
For D = (T−t) W · L,
2S ・ L> D
Forming the convex portion so as to satisfy the above-mentioned conditions . D = (T−t) V · L , where d is the amount of the molten heat-fusible resin layer flowing into the recess from the pressing surface between the heater inner surface and the recess The recess is
2S · L> D + d
The manufacturing method of the film-clad battery of Claim 4 which forms the said convex part so that it may satisfy | fill.

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