JP2006147485A - Manufacturing method of power storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably manufacture a power storage device reduced in assembling error by improving the positioning precision of respective members in a process of manufacturing the power storage device. <P>SOLUTION: A positive electrode current collector 5 is sandwiched from both face sides by a positive electrode active material film 6 supported by a carrier film 41, and made to be mutually crimped while being heated. A positive electrode preliminary body 27 in which positive electrode active material films 6, 6 and the positive electrode current collector 5 are integrated is supported by the carrier film 41 from one face side. Based on a reference hole 41t formed in advance in the carrier film 41, a process for obtaining a positive electrode 7 by cutting the positive electrode preliminary body 27, and a process for assembling a cell 20 by the positive electrode 7, a negative electrode 10, and a separator 3 are carried out. The base material annealed after stretching is used for the carrier film 41. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a power storage device such as a lithium battery or an electric double layer capacitor.

  Today, lithium ion secondary batteries are widely used as power storage devices for various electronic devices such as mobile communication devices and portable computers. Moreover, although practical use has not progressed sufficiently, electric double layer capacitors and fuel cells are expected as next-generation power storage devices. Many of these power storage devices have a structure in which several layers of product members are stacked. For example, a lithium ion secondary battery has a structure in which a separator is sandwiched between a positive electrode and a negative electrode.

When manufacturing a power storage device as exemplified, it is often inevitable to handle a film-like member that is thin and difficult to handle. Therefore, it is necessary to support such a thin film-like member with some support means when manufacturing the electrode plate group. A conventional carrier means is a resin carrier film. Taking a lithium-ion secondary battery as an example, the active material film for the electrode is thin (several tens of μm) and is not self-supporting. Therefore, the carrier, film assembly process, and cell assembly are carried on the carrier film. Provided to the process. As disclosed in the following Patent Document 1, when the active material film and the current collector are thermocompression bonded on the carrier film, and the non-product part is removed by half-cutting the obtained electrode preliminary body, Only the electrode remains. Since the reference hole is provided in advance in the carrier film, the step of half-cutting the electrode preliminary body and the step of integrating the positive electrode, the negative electrode and the separator can be performed using the reference hole. Thereby, the alignment precision of members is ensured.
Japanese Patent No. 3325227

  By the way, in the process of manufacturing the illustrated power storage device, heat may be applied to the film-like member placed on the carrier film for the purpose of drying and / or pressure bonding. In a lithium ion secondary battery, for example, it is a step of thermocompression bonding an active material film and a current collector on a carrier film. This heating may cause the carrier film to shrink, resulting in a misalignment of the reference hole.

  If the carrier film has a uniform shrinkage rate everywhere, the reference hole may be formed in advance in anticipation of the shrinkage. However, the carrier film exhibits different shrinkage rates depending on the location as well as different shrinkage rates in the vertical and horizontal directions. Further, the shrinkage rate changes according to the heating temperature. In other words, there is a variation in the position of the reference hole, which is unpredictable. This fact is an obstacle to improving the alignment accuracy between members.

  An object of the present invention is to improve the alignment accuracy of members in the process of manufacturing a power storage device such as a lithium battery, and to stably manufacture a power storage device with a small assembly error.

Means for Solving the Problems and Effects of the Invention

  In order to solve the above problems, a method for manufacturing a power storage device according to the present invention includes a step of supporting a film-like member that provides a power storage action on a resin carrier film, a step of heating the film-like member together with the carrier film, and heating. A step of aligning the film-like member supported by the carrier film with the second member to constitute the power storage device based on a reference position determined on the carrier film, and integrating the two; And the carrier film is characterized by using a substrate annealed after stretching.

  Preferably, a step of forming a reference mark on the carrier film, a step of heating the film-like member together with the carrier film after the formation of the reference mark, a film-like member supported by the carrier film after the heating, and the power storage device Alignment with the second member to be configured is performed using a reference mark, and a process of integrating the two is performed.

  According to the method of the present invention, since the substrate annealed in advance is used for the carrier film, the shrinkage of the carrier film in the step of heating the film-like member can be reduced. Therefore, the reference position defined on the carrier film is unlikely to be distorted, and the film member and the second member can be aligned with high accuracy. As a result, a power storage device with a small assembly error can be manufactured stably.

  For example, the outer shape of the carrier film can be used for such a reference position, but it is preferable to separately form a reference mark. Furthermore, a reference hole penetrating the front and back of the carrier film is suitable as the reference mark. According to the reference hole penetrating the front and back, a fixing tool such as a pin can be directly inserted, so that the film member and the second member can be easily and easily aligned. Since the position of the reference hole does not change due to heat shrinkage, heating is performed after forming the reference hole in the carrier film, and then the film member and the second member are aligned using the reference hole. , Both can be aligned accurately.

  In a preferred embodiment, the power storage device manufactured according to the present invention is a lithium ion secondary battery or an electric double layer capacitor. In this case, the film-like member is an active material film for positive electrode or negative electrode, and the second member is a current collector for positive electrode or negative electrode. The step of heating the film-like member is a step of drying the active material film on the carrier film. The step of integrating the film-like member and the second member is performed by aligning the active material film supported by the carrier film with the current collector using the reference mark, and pressing both of them while heating. Thus, an electrode preliminary body having an active material film and a current collector is obtained.

  In another preferred embodiment, the step of heating the film-like member (active material film) is performed by pressing the active material film supported by the carrier film and the positive electrode or negative electrode current collector while heating. In this way, an electrode preliminary body in which the active material film and the current collector are integrated is obtained. Furthermore, after the fiducial mark is formed, the electrode preliminary body having an active material film as a film-like member and supported from one side by the carrier film is cut on the carrier film without dividing the carrier film. Thus, a step of removing the cutting allowance portion from the carrier film can be performed in a form in which only the positive electrode or the negative electrode is left on the carrier film while the molded positive electrode or the molded negative electrode is obtained. In addition, the step of integrating the film-like member and the second member includes a positive electrode supported by a carrier film and having an active material film as a film-like member, and a carrier film different from the positive electrode. The positioning with the negative electrode as the second member is performed using the reference mark, and the step of pressing the both while sandwiching the separator is performed.

  Specifically, in the step of obtaining the electrode preliminary body, a pair of positive electrode or negative electrode active material films supported by a carrier film is prepared, and the current collector is prepared by the pair of active material films supported by the carrier film. A sub-process for forming an electrode preliminary by sandwiching the two while heating, and removing the carrier film on the other side so that the electrode preliminary is supported only by the carrier film on one side Sub-process.

  In another aspect, the method for manufacturing a power storage device of the present invention includes a step of preparing a film-like positive electrode on a resin carrier film, and a step of preparing a film-like negative electrode on a resin carrier film; A step of forming a fiducial mark on the carrier film, a step of crimping the positive electrode and the negative electrode while heating with a separator interposed therebetween, a step of removing the carrier film supporting the negative electrode after the thermocompression bonding, A step of crimping the positive electrode, the negative electrode, and the separator to each other, including a step of crimping the other positive electrode supported by the carrier film while heating, sandwiching another separator on the surface side from which the carrier film has been removed Then, each member is aligned based on the reference mark, and the carrier film is annealed after stretching. And main characteristic the use of the substrates.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. For convenience of explanation, the same reference numerals are used for the active material film and the active material layer in the drawings. In the specification, the manufacturing stage is referred to as the active material film, and the finished product as the active material layer.

  FIG. 1 is a schematic cross-sectional view of a lithium ion secondary battery 1 (hereinafter also simply referred to as battery 1) manufactured by the method of the present invention. FIG. 2 is a schematic cross-sectional view of a cell 20 (unit structure) forming the main part of the battery 1. When a plurality of cells 20 are stacked, a cell stack 2 is obtained. As shown in FIG. 1, the battery 1 has a structure in which a cell stack 2 is enclosed in a container 4 made of a laminate film. Since the cell 20 is actually designed to be a thin flat plate, the cell stack 2 and the battery 1 are also plate-shaped. Moreover, although the shape of the cell 20 assumes a rectangular shape (rectangular shape), various shapes such as a polygonal shape other than the rectangular shape, a circular shape, and an elliptical shape can be employed. Such a high degree of freedom in shape is one of the advantageous features of the stacked lithium ion secondary battery 1. Further, in FIG. 1, the battery 1 is configured using a plurality of cells 20, but a lithium ion secondary battery including only one cell 20 can also be manufactured.

  As shown in FIG. 2, the cell 20 has a bicell structure in which separators 3 and 3 are sandwiched between positive electrodes 7 and 7 and a negative electrode 10. The positive electrode 7 has a structure in which a positive electrode active material layer 6 is laminated on a positive electrode current collector 5. On the other hand, the negative electrode 10 has a structure in which negative electrode active material layers 9 and 9 are laminated on a negative electrode current collector 8. In this embodiment, the negative electrode 10 is shared by the two separators 3 and 3 so that the side of each separator 3 and 3 not facing the negative electrode 10 is individually covered with the positive electrodes 7 and 7. ing. The arrangement of the positive electrode 7 and the negative electrode 10 may be interchanged.

  The positive electrode current collector 5 can be composed of a foil or a metal mesh made of Al or an Al alloy. The negative electrode current collector 8 can be composed of a foil or a metal mesh made of Cu or a Cu alloy. Among these, it is preferable to use a metal mesh from the viewpoints of maintaining adhesion to the active material layer, securing the volume of the active material layer, diffusibility of lithium ions, and the like. As the metal mesh, any of expanded metal, etching metal and punching metal can be used.

The positive electrode active material layer 6 includes a positive electrode active material, a conductive additive, and a polymer substrate (binder). Similarly, the negative electrode active material layer 9 includes a negative electrode active material, a conductive additive, and a polymer substrate. The separator 3, the positive electrode active material layer 6 and the negative electrode active material layer 9 have a porous form, and are impregnated with a nonaqueous electrolytic solution in which a lithium salt such as LiPF ₆ is dissolved in an organic solvent such as ethylene carbonate or propylene carbonate. Has been. That is, the battery 1 is configured as a lithium ion polymer secondary battery.

  Examples of the polymer substrate constituting the positive electrode active material layer 6 and the negative electrode active material layer 9 include fluororesins such as polyvinylidene fluoride (PVDF), hexafluoropropylene (HFP), polytetrafluoroethylene (PTEF), and the like. A copolymer of fluororesin can be used.

As the positive electrode active material constituting the positive electrode active material layer 6, a lithium composite oxide containing a transition metal or a typical metal such as LiMnO ₂ , LiCoO ₂ , or LiNiO ₂ can be used. As the negative electrode active material constituting the negative electrode active material layer 9, a graphite-based carbon material such as a mesofuse carbon material is suitable. In addition, conductive carbon such as acetylene black can be used as the conductive auxiliary agent (conductive substance).

The separator 3 can be composed of a microporous film of an insulating resin such as polyethylene or polypropylene. Moreover, it is also possible to comprise the same material as the polymer substrate contained in the positive electrode active material layer 6 and the negative electrode active material layer 9, such as PVDF, HFP, or a copolymer thereof (filler such as SiO ₂ is used). May be mixed). Furthermore, a microporous membrane having a multi-layer structure in which polyethylene is sandwiched between polypropylene, a microporous membrane having a resin layer such as polyethylene or polypropylene, and a resin layer made of PVDF, HFP, or a copolymer thereof, etc. It can also be used as a material for the separator 3.

  As shown in FIG. 1, one end of strip-like lead terminals 12 and 13 is connected to the cell stack 2. The other ends of the lead terminals 12 and 13 extend outward through the seal portion 11 (fusion allowance) of the container 4. Specifically, the power extraction portions 50 of the positive electrode current collector 5 are bundled together and one end of the positive electrode lead terminal 12 is connected. The power extraction portion 80 of the negative electrode current collector 8 is bundled together, and one end of the negative electrode lead terminal 13 is connected. In this way, the cells 20 are connected in parallel. The positive lead terminal 12 may be made of, for example, aluminum or an aluminum alloy. The lead terminal 13 for the negative electrode is preferably composed of copper, copper alloy, nickel, nickel alloy, nickel-plated copper, or nickel-plated copper alloy.

  As shown in FIG. 3, the container 4 in which the cell stack 2 is sealed is composed of a laminate film 34 in which resin layers 31 and 33 are provided on both surfaces of a metal foil 32 such as an aluminum foil. For the resin layer 31 to be exposed to the outside of the container 4, for example, polyethylene terephthalate or biaxially stretched nylon can be used. For the resin layer 33 to be on the inner side, a material such as polyethylene or polypropylene that has heat-fusibility, resistance to an electrolytic solution, and low water vapor permeability can be used. By melting and solidifying the inner resin layer 33, the upper and lower laminate films 34, 34 are bonded together to form the seal portion 11.

Next, a method for manufacturing the lithium ion secondary battery 1 will be described.
A cell 20 that is a power storage component of the lithium ion secondary battery 1 is manufactured as follows. First, an active material film for a positive electrode or a negative electrode is prepared from a material such as an active material. The active material film is thermocompression bonded to the current collector, and then cut into a square shape to obtain a positive electrode or a negative electrode. The positive electrode, the negative electrode, and the separator are thermocompression bonded to obtain the cell 20. If a plurality of cells 20 are stacked, the cell stack 2 is obtained. The battery 1 can be obtained by impregnating the cell 20 or the cell stack 2 with the electrolytic solution and wrapping the laminate with the laminate film 34. Hereinafter, it demonstrates in detail according to a process.

(Active material film production process)
As shown in FIG. 4, the positive electrode active material film 6 is directly formed on the carrier film 41 by the molding device 43. The forming apparatus 43 is shown in FIG. The molding device 43 includes a paste coating device 401 and a drying device 407. The paste coating apparatus 401 is an apparatus that employs a known doctor blade system that coats the positive electrode active material paste 6 ′ on the belt-like carrier film 41 that moves in one direction while maintaining a certain gap with the blade 402. is there. The positive electrode active material paste 6 ′ prepared in the paste coating apparatus 401 is prepared by kneading an organic solvent such as acetone and materials such as an active material, a conductive additive, a plasticizer, and a polymer substrate. It is. The drying device 407 is configured such that the undried positive electrode active material film 6 supported by the carrier film 41 is conveyed between the pair of infrared heaters 403 and 405. The positive electrode active material film 6 is dried in a drying apparatus 407 in a temperature range of 90 ° C. or higher and 140 ° C. or lower. In this way, the positive electrode active material film 6 formed into a strip shape is produced. The positive electrode active material film 6 has a self-supporting property, but since the self-supporting property is poor, the positive electrode active material film 6 is used for manufacturing the positive electrode 7 while being supported by the carrier film 41.

  Although the materials used are different, the negative electrode active material film 9 (FIG. 4) can be produced by the same procedure as that of the positive electrode active material film 6. Also in the following description, the manufacturing procedure of the positive electrode 7 can be used for the manufacturing procedure of the negative electrode 10.

  Moreover, said carrier film 41 can be comprised with a kind of resin base material selected from the group of a polyethylene terephthalate, a polypropylene, polyethylene, and a polyimide. Among these, polyethylene terephthalate resin is recommended because it is excellent in various viewpoints such as cost, strength, heat resistance, and chemical resistance. Moreover, you may mix fillers, such as a silica, in these resin base materials as needed.

  The resin-made carrier film 41 is produced by extruding a resin into a thick sheet with an extruder, cooling it appropriately, and stretching it in the vertical and horizontal biaxial directions. Therefore, internal stress remains in the stretching direction and shrinks when heated. Therefore, a resin film that is annealed after stretching to sufficiently reduce internal stress is adopted as the carrier film 41. Thereby, shrinkage | contraction at the time of heating the carrier film 41 can be reduced. Further, the thickness of the carrier film 41 is not particularly limited, but can be, for example, 38 μm or more and 100 μm or less. Although the annealing treatment is performed, if the carrier film 41 is too thin, the carrier film 41 may be significantly deformed when heated. On the other hand, if it is too thick, the material cost increases.

(Reference hole forming process)
Returning to FIG. The positive electrode active material film 6 formed by the forming device 43 is conveyed while being supported by the carrier film 41, and is guided to the punching device 45 together with the carrier film 41. In the punching device 45, a plurality of reference holes 41t are formed at regular intervals in the length direction (winding direction) of the belt-like carrier film 41. In the example of FIG. 4, the positive electrode active material sheet 6 is punched together with the carrier film 41 in order to form the reference hole 41 t in the carrier film 41. However, the area | region of the both ends of the width direction (direction orthogonal to a length direction) of the carrier film 41 is made into the area | region for forming the reference holes 41t and 41t, and the positive electrode active material film 6 is shape | molded avoiding the area | region. It may be.

  In the present embodiment, the reference holes 41t and 41t are formed in two rows (plurality) on both sides of the carrier film 41, but it is also possible to form only one row. However, from the viewpoint of alignment accuracy, it is preferable to align the members using a plurality of reference holes 41t and 41t. When the formation of the reference hole 41t is completed, the positive electrode active material film 6 and the carrier film 41 are wound up in a roll shape. Similarly, the negative electrode active material film 9 wound in a roll shape together with the carrier film 41 in which the reference hole 41t is formed is prepared. If alignment is possible using the outer shape of the carrier film 41 as a reference, the reference hole 41t need not be formed.

  The reference hole 41t can be provided before the active material film 6 is formed on the carrier film 41. That is, as shown in FIG. 9, the punching device 45 guides the carrier film 41 provided with the reference hole 41 t in advance to the molding device 43. Then, the positive electrode active material paste 6 ′ is applied to the carrier film 41 and then dried. Thereby, the positive electrode active material film 6 supported by the carrier film 41 is obtained. In this embodiment, both end regions 41h and 41h in the width direction in which the reference holes 41t and 41t are formed are regions where the positive electrode active material film 6 is not disposed. Since the punching is performed in a state where the active material paste 6 'is not applied, the punching tool is hardly damaged.

  Further, since the carrier film 41 is annealed in advance, the thermal shrinkage when the positive electrode active material paste 6 ′ is dried is extremely small. Therefore, even when the positive electrode active material paste 6 ′ is applied on the carrier film 41 in which the reference holes 41 t have been formed and a drying process is performed by heating, the position change between the reference holes 41 t is extremely small.

  FIG. 16 is a graph showing the results of examining the shrinkage amount of a belt-like carrier film made of polyethylene terephthalate resin annealed after biaxial stretching and a belt-like carrier film made of polyethylene terephthalate resin that was not annealed. Specifically, as shown in FIG. 13, four small holes TH having a center interval of 60 mm in the winding direction RL and 40 mm in the width direction WL (direction perpendicular to the winding direction) are drilled at various temperatures and tension free. The amount of change in the center interval between the two small holes TH and TH after heating for 10 seconds was examined. As can be seen from FIG. 16A, the effect of annealing is not so great in the width direction WL. However, as can be seen from FIG. 16B, the effect of the annealing treatment increases as the heating temperature increases in the winding direction RL. In particular, the effect of the annealing treatment is remarkable in the region where the heating temperature is 80 ° C. or higher.

(Preliminary electrode production process)
Next, as shown in FIG. 5, a step is performed in which the positive electrode active material film 6 wound in a roll with the carrier film 41 and the positive electrode current collector 5 are pressure-bonded while both are heated. By this step, the positive electrode preliminary body 27 in which the positive electrode active material film 6 and the positive electrode current collector 5 are integrated can be obtained. In the present embodiment, a metal mesh is used as the positive electrode current collector 5, and the positive electrode active material films 6 and 6 are arranged on both sides of the positive electrode current collector 5. Therefore, in the thickness direction, the three members are bonded to the pressure roller pair 47 (heat roller) so that one positive electrode active material film 6, the positive electrode current collector 5 and the other one positive electrode active material film 6 overlap in this order. It is fed out toward the crimping tool. The pressure roller pair 47 is a part of a known calendar roll device and is heated to a predetermined temperature. The positive electrode active material films 6 and 6 and the positive electrode current collector 5 are thermocompression-bonded and integrated by receiving the pressurizing action and heating action of the pressure-bonding roller pair 47.

  The pressure roller pair 47 incorporates a heater such as a heating resistor. The temperature of the pressure roller pair 47 is controlled by a controller (not shown) and maintained at a constant temperature. The thermocompression bonding using the pressure roller pair 47 is desirably performed so that the temperature of the positive electrode active material film 6 falls within a range of 100 ° C. or higher and 140 ° C. or lower (more preferably 110 ° C. or higher and 130 ° C. or lower). When the temperature of the positive electrode active material film 6 is less than 100 ° C., the adhesion between the positive electrode active material film 6 and the positive electrode current collector 5 may be insufficient. On the other hand, when the temperature of the positive electrode active material film 6 exceeds 140 ° C., the softening of the fluororesin (PVDF, HFP) contained in the positive electrode active material film 6 becomes remarkable, and various characteristics of the battery (capacity, charge / discharge) There is a risk of deteriorating cycle characteristics). In addition, it is preferable to preheat the positive electrode active material film 6 wound in a roll shape because the temperature range can be quickly reached during thermocompression bonding.

  The carrier film 41 is provided with a reference hole 41t in the reference hole forming step shown in FIG. The reference hole 41t can be used as a reference mark for accurately overlaying the positive electrode active material films 6 and 6 on the positive electrode current collector 5 in the electrode preliminary body manufacturing step of FIG. For example, as shown in the schematic side view of FIG. 10, the carrier sprocket 49 is engaged with a reference hole 41 t provided in the carrier film 41, and the carrier sprocket 49 is operated to support the carrier film 41 and the carrier film 41. The formed positive electrode active material film 6 is conveyed. The actuators that drive the transport sprockets 49 and 49 are controlled so that the operation amounts of the two transport sprockets 49 and 49 positioned above and below the positive electrode current collector 5 are equal. If it does so, the positive electrode active material film 6 located in the one surface side of the positive electrode collector 5 and the positive electrode active material film 6 located in the other surface side will be exactly synchronized, and one positive electrode current collector will be carried out. The positive electrode active material film 6 that can be superimposed on the body 5 and guided to the gap between the pressure roller pair 47 and pressed against the positive electrode current collector 5 is not distorted or cracked. Further, since the transport sprocket 49 is engaged with the reference hole 41t and the movement of the carrier film 41 in the width direction is restricted, the alignment accuracy of the positive electrode active material film 6 and the positive electrode current collector 5 in the width direction is also increased. .

  Further, in the present invention, a resin base material that has been previously annealed is used for the carrier film 41. Therefore, even when the process sequence described in FIG. 9 (reference hole forming process → active material film manufacturing process) is adopted, the carrier film 41 does not undergo large thermal shrinkage, and the position of the reference hole 41t does not change. If the reference hole 41t is used, the positive electrode active material films 6 and 6 and the positive electrode current collector 5 can be accurately aligned. Of course, even after the process shown in FIG. 5, the carrier film 41 that supports the positive electrode preliminary body 27 does not shrink significantly.

  FIG. 14 is a detailed exploded top view of the positive electrode preliminary body 27. In the positive electrode preliminary body 27, the positive electrode current collector 5 is exposed at a portion that becomes the power extraction portion 50 (FIG. 2) of the positive electrode 7. That is, when forming the reference hole 41t, the positive electrode active material film 6 is punched together with the carrier film 41 to form the window 6k. In this way, when the positive electrode active material film 6 and the positive electrode current collector 5 are integrated, the positive electrode current collector 5 is naturally exposed from the window 6k. And it can prevent that the positive electrode active material film 6 is arrange | positioned at the electric power extraction part 50 by forming the electric power extraction part 50 using this exposed part. It is easy to connect the lead terminal 12 shown in FIG. 1 to the power extraction portion 50 where the positive electrode active material film 6 is not disposed. Further, when the positive electrode active material films 6, 6 are thermocompression bonded to both surfaces of the positive electrode current collector 5, the positions of the windows 6 k, 6 k of the positive electrode active material films 6, 6 are obtained by using the reference holes 41 t, 41 t. Matching is made natural. Of course, the power extraction portion 80 of the negative electrode 10 can also be formed in the same manner as the power extraction portion 50 of the positive electrode 7.

  Further, as shown in FIG. 14, by using the positive electrode current collector 5 having a width slightly smaller than the interval between the reference holes 41t and 41t, the positive electrode current collector 5 is not exposed at the reference holes 41t and 41t. . This facilitates an operation of inserting a positioning pin or the like into the reference hole 41t.

  Returning to FIG. The positive electrode active material film 6 is subjected to thermocompression bonding by the pressure roller pair 47 while being supported by the carrier film 41. Therefore, the pressure roller pair 47 does not directly contact the positive electrode active material film 6. The carrier film 41 also plays a role of protecting the positive electrode active material film 6. However, after completion of the thermocompression bonding, the carrier film 41 on one surface side is not necessary. Therefore, as shown in FIG. 5, the carrier film 41 on one side (the lower side in the figure) is continuously supported by the carrier film 41 on one side, while the carrier film 41 on the other side (the upper side in the figure) is peeled off from the positive electrode preliminary body 27. .

  In addition, about the carrier film 41 peeled and removed in FIG. 5, you may comprise with the resin base material which is not annealed. The carrier film 41 and the positive electrode active material film 6 supported by the carrier film 41 can be accurately conveyed without depending on the reference hole 41t as shown in FIG. For example, the carrier film 41 can be conveyed by a feed roller while guiding the width direction of the carrier film 41 with a rail or the like. In addition, the alignment accuracy required in the step of producing the positive electrode preliminary body 27 by thermocompression bonding of the positive electrode current collector 5 and the positive electrode active material films 6 and 6 is the same as that of the positive electrode 7, the negative electrode 10, and the separator 3 described later. Not as much as the process of assembling 20. Taking such circumstances into consideration, as shown in FIG. 11, only the carrier film 41 that uses the resin base material that has not been annealed as the carrier film 41 ′ to be peeled and removed and continues to support the resulting positive electrode preliminary body 27. A method of using a resin base material that has been subjected to an annealing treatment is also conceivable. Since the annealing treatment is not performed, the carrier film 41 'is inexpensive. Further, the reference hole 41t may not be formed in the carrier film 41 'to be peeled and removed. In that case, since the step of forming the reference hole 41t can be omitted, a reduction in manufacturing cost can be expected.

  Further, regarding the reference hole 41t of the carrier film 41, it may be formed together in an electrode manufacturing process (FIG. 6) described later. For example, in the process sequence as disclosed in the above-mentioned patent document, the window 6k as shown in FIG. 14 is not required, so that a reference hole may be provided immediately before the cutting process for forming the electrode. Is possible.

(Electrode production process)
Next, as shown in FIG. 6, the positive electrode preliminary body 27 supported from one side by the carrier film 41 is cut by a cutting device 47 to obtain the formed positive electrode 7. In the cutting device 47, the positive electrode preliminary body 27 is cut as shown in the schematic cross-sectional view of FIG. FIG. 12 is a diagram schematically showing an AA cross section in FIG. 6. The cutting device 47 includes a cutting die 65 including a cutter 69 (for example, a Thomson blade) and an alignment pin 67, and a support base 63 that supports the carrier film 41 and the positive electrode preliminary body 27. The positive electrode preliminary body 27 is transported to the support base 63 together with the carrier film 41 and temporarily stops. The cutting die 65 is brought close to the positive electrode preliminary body 27 and the carrier film 41, and first, the alignment pin 67 is inserted into the reference hole 41 t of the carrier film 41. With this, the positions of the positive electrode preliminary body 27 and the carrier film 41 are fixed. The cutter 69 is stopped at a position where a shallow groove is formed in the carrier film 41. Then, the positive electrode preliminary body 27 can be cut while being supported by the carrier film 41 without dividing the carrier film 41. Further, according to the cutting method as shown in FIG. 12, the relative positions of the positive electrode 7 and the reference hole 41t obtained are constant. By alternately carrying and cutting the carrier film 41 and the positive electrode active material film 6, the positive electrode 7 can be formed so as to be continuous in the length direction of the carrier film 41. The reason why the reference holes 41t are provided at regular intervals in the length direction of the carrier film 41 is to continuously produce the positive electrode 7 in this way.

  The cutting of the positive electrode preliminary body 27 will be described in detail with reference to FIG. The cutting line CL (half-cut line) of the positive electrode preliminary body 27 is set so that the power extraction unit 50 is formed at the window 6k. Since the relative positional relationship between the reference hole 41t and the window 6k is constant, the power extraction portion 50 can be formed by aligning the cutter 69 of the cutting device 47 of FIG. 12 with the cutting line CL. As in the present embodiment, when a metal mesh is used for the positive electrode current collector 5, it is desirable that the cutting line CL does not cover the window 6 k except for the power extraction unit 50. This is because burrs can be prevented from occurring in the positive electrode current collector 5 and the reliability of the lithium ion secondary battery 1 can be improved. In this embodiment, since the annealed carrier film 41 is used, the positions of the reference hole 41t and the window 6k before and after the step of thermocompression bonding the positive electrode active material film 6 and the positive electrode current collector 5 are performed. The change in the relationship is very small. Therefore, the positive electrode preliminary body 27 can be accurately cut along the cutting line CL.

  However, as mentioned above, in the cutting step of FIG. 6, the operation of cutting the positive electrode preliminary body 27 to obtain the positive electrode 7 and the operation of forming the reference hole 41t can be performed at the same time. In this case, a cutter (cutting die) for forming the reference hole 41t is substituted for the alignment pin 67 of FIG.

  Returning to FIG. After the positive electrode preparatory body 27 is cut and the outer shape of the positive electrode 7 is adjusted, the step of removing the cutting margin portion 61 from the carrier film 41 in the form of leaving only the formed positive electrode 7 on the carrier film 41 is subsequently performed. Do. Only the positive electrode 7 remains on the carrier film 41. The positive electrode 7 supported by the carrier film 41 is wound into a roll together with the carrier film 41 so as not to be bulky. Further, the negative electrode 10 supported by the carrier film 41 is obtained by the same procedure as that for the positive electrode 7.

(Cell assembly process)
Next, as shown in FIG. 7, the step of assembling the cell 20 by integrating the positive electrodes 7, 7, the negative electrode 10, and the separators 3, 3 by thermocompression is performed. As described with reference to FIG. 2, since the cell 20 has a bi-cell structure, it is necessary to press-bond two layers of positive electrodes 7 and 7 and one layer of negative electrode 10. Since two separators 3 and 3 are necessary, for convenience, five members are integrated, which is a little troublesome. Therefore, as in the present embodiment of FIG. 7, the first pressure roller pair 471 is disposed at the first upstream position in the transport direction of the carrier film 41, and the second pressure roller pair 472 is disposed at the second downstream position. The cell 20 can be assembled by placing and repeating the thermocompression bonding operation twice. In each of the first position and the second position, the positive hole 7 supported by the carrier film 41 and the negative hole 10 supported by the carrier film 41 different from the positive electrode 7 are aligned with the reference holes 41t and 41t. And performing pressure bonding while heating the separator 3 with the separator 3 interposed therebetween.

  Specifically, as the method for aligning the positive electrode 7 and the negative electrode 10, for example, the method described with reference to FIG. That is, a transport sprocket (not shown) that engages with the reference hole 41 t of the carrier film 41 is disposed on the upstream side in the transport direction of the first pressure roller pair 471. If the movement amount of the transport sprocket on the positive electrode 7 side is equal to the movement amount of the conveyance sprocket on the negative electrode 10 side, the positive electrode 7 and the negative electrode 10 can be accurately aligned. A similar method can be adopted for the second pressure roller pair 472 side.

  Further, the temperatures of the first pressure roller pair 471 and the second pressure roller pair 472 are controlled by a controller (not shown) and maintained at a constant temperature. The thermocompression bonding using the pressure roller pairs 471 and 472 is performed so that the temperatures of the positive electrode 7, the negative electrode 10, and the separator 3 are within a range of 100 ° C. or higher and 140 ° C. or lower (more preferably 115 ° C. or higher and 125 ° C. or lower). desirable. When the temperature of each component is less than 100 ° C., the adhesion between the three members of the positive electrode 7, the negative electrode 10 and the separator 3 may be insufficient. On the other hand, when the temperature of each component exceeds 140 ° C., softening of the fluororesin (PVDF, HFP) contained in the positive electrode 7 and the negative electrode 10 becomes remarkable, and various characteristics of the battery (capacity, charge / discharge cycle characteristics, etc.) ) May be reduced. When a resin microporous membrane is used as the separator 3, it is important to perform the thermocompression bonding step shown in FIG. 7 at a temperature lower than the temperature at which the micropores are blocked (shut down).

  Further, as a method of thermocompression bonding the positive electrode 7, the negative electrode 10, and the separator 3 with each other, a thermocompression bonding device 79 as shown in FIG. 15 can be used. The thermocompression bonding device 79 includes an upper surface pressing device 75 and a lower surface pressing device 77. The lower surface pressing device 77 is provided with pins 73 and 73. The pins 73 and 73 are devised so that they do not sink into the lower surface pressing device 77 and prevent the upper surface pressing device 75 and the lower surface pressing device 77 from approaching each other. The positive electrode 7 and the negative electrode 10 guided between the upper surface pressing device 75 and the lower surface pressing device 77 are aligned by inserting pins 73 and 73 into the reference holes 41t and 41t of the carrier films 41 and 41, respectively. The separator 3 is aligned with the positive electrode 7 and the negative electrode 10 with reference to its external shape. In a state where the pins 73 and 73 are inserted into the reference holes 41t and 41t, the upper surface pressing device 75 and the lower surface pressing device 77 are brought close to each other, whereby the positive electrode 7, the negative electrode 10, and the separator 3 are thermocompression bonded.

  After producing the cells 20 as described above, a step of separating the cells 20 from the carrier film 41 and cutting into the individual cells 20 is performed. A cell stack 2 is obtained by stacking a plurality of cells 20. The power extraction parts 50 and 80 of each cell 20 are bent and bundled as shown in FIG. The lead terminals 12 and 13 are welded to the bundled power extraction portions 50 and 80 by a technique such as ultrasonic welding, resistance welding, spot welding, or laser welding. It is also possible to join the two by caulking instead of welding.

  After the lead terminals 12 and 13 are attached, the cell 2 is wrapped with a laminate film 34 and impregnated with a non-aqueous electrolyte. If the inside of the container 4 composed of the laminate film 34 is sealed while reducing the pressure from atmospheric pressure, the lithium ion secondary battery 1 shown in FIG. 1 is obtained.

  So far, the manufacturing method of the lithium ion secondary battery 1 has been described, but most of the description can be applied to the manufacturing method of the electric double layer capacitor. For example, if the same binder (fluorine-containing resin) as that of the lithium ion secondary battery 1 is used, the temperature at the time of thermocompression bonding can be substantially the same as that of the lithium ion secondary battery 1. Naturally, various manufacturing conditions such as the pressing force of the pressure roller used at the time of thermocompression bonding are appropriately adjusted regardless of whether it is a lithium ion secondary battery or an electric double layer capacitor.

The cross-sectional schematic diagram of the lithium ion secondary battery manufactured by the method of this invention. The detailed cross-sectional schematic diagram of a cell. The expanded cross-sectional schematic diagram of a laminate film. Process explanatory drawing of the manufacturing method concerning this invention. Process explanatory drawing following FIG. Process explanatory drawing following FIG. Process explanatory drawing following FIG. Detailed explanatory drawing of the formation process of an active material film. The figure explaining the process of another aspect. The side surface schematic diagram of FIG. 5 which shows the procedure which aligns using the reference | standard hole formed in the carrier film. Process explanatory drawing which shows the modification of FIG. The schematic diagram of the AA cross section shown in FIG. The schematic diagram explaining the formation form of a small hole. FIG. 3 is a detailed exploded top view of the positive electrode preliminary body. The figure explaining the method of thermocompression bonding a positive electrode, a negative electrode, and a separator mutually. The graph of the result of investigating the effect of annealing treatment.

Claims (10)

A step of supporting a film-like member (6, 9) that provides a storage effect on a resin carrier film (41);
Heating the film-like member (6, 9) together with the carrier film (41);
After the heating, the film-like member (6, 9) supported by the carrier film (41) and the second member (5, 8, 3, 7, 10) to constitute the power storage device (1) And positioning based on the reference position (41t) defined for the carrier film (41), and integrating the two,
The manufacturing method of the electrical storage apparatus (1) characterized by using the base material annealed after extending | stretching for the said carrier film (41). A step of supporting a film-like member (6, 9) that provides a storage effect on a resin carrier film (41);
Forming a reference mark (41t) on the carrier film (41);
Heating the film-like member (6, 9) together with the carrier film (41) after the formation of the reference mark (41t);
After the heating, the film-like member (6, 9) supported by the carrier film (41) and the second member (5, 8, 3, 7, 10) to constitute the power storage device (1) And positioning using the reference mark (41t) and integrating the two,
The manufacturing method of the electrical storage apparatus (1) characterized by using the base material annealed after extending | stretching for the said carrier film (41).   The manufacturing method of the electrical storage apparatus (1) of Claim 1 or 2 with which the said base material is comprised with 1 type of resin selected from the group of a polyethylene terephthalate, a polypropylene, polyethylene, and a polyimide.   The manufacturing method of the electrical storage apparatus (1) of any one of Claim 1 thru | or 3 which heats the said film-form member (6, 9) in 90 to 140 degreeC.   The method for manufacturing a power storage device (1) according to claim 2, wherein the reference mark (41t) is a reference hole penetrating the front and back of the carrier film (41). The power storage device (1) is a lithium ion secondary battery (1) or an electric double layer capacitor,
The film-like member (6, 9) is an active material film (6, 9) for the positive electrode (7) or the negative electrode (10), and the second member (5, 8) is for the positive electrode (7). Or a current collector (5, 8) for the negative electrode (10),
The step of heating the film-like member (6, 9) is a step of drying the active material film (6, 9) on the carrier film (41),
The step of integrating the film-like member (6, 9) and the second member (5, 8) includes the active material film (6, 9) supported by the carrier film (41), Alignment with the current collector (5, 8) is performed using the reference mark (41t), and both are bonded while heating, whereby the active material film (6, 9) and the current collector ( 6. The method for manufacturing a power storage device (1) according to claim 2 or 5, which is a step of obtaining an electrode preparatory body (27, 29) having 6, 9). The power storage device (1) is a lithium ion secondary battery (1) or an electric double layer capacitor,
The film-like member (6, 9) is an active material film (6, 9) for the positive electrode (7) or the negative electrode (10),
The step of heating the film-like member (6, 9) includes the active material film (6, 9) supported by the carrier film (41) and the positive electrode (7) or the negative electrode (10). An electrode preliminary body (27, 29) in which the active material film (6, 9) and the current collector (5, 8) are integrated by pressing the current collector (5, 8) while heating. )
After the formation of the reference mark (41t), the active material film (6, 9) as the film-like member (6, 9) is provided, and the carrier film (41) is supported from one side. By cutting the electrode preliminary body (27, 29) on the carrier film (41) without dividing the carrier film (41), the molded positive electrode (7) or the molded negative electrode (10) And a step of removing the cutting margin portion (61) from the carrier film (41) in such a manner that only the positive electrode (7) or the negative electrode (10) is left on the carrier film (41). ,
The step of integrating the film-like member (6, 9) and the second member (7, 10) includes the active material film (6) as the film-like member (6) and the carrier film. The positive electrode (7) supported by (41) and the negative electrode (10) as the second member (10) supported by the carrier film (41) different from the positive electrode (7). The method of manufacturing a power storage device (1) according to claim 2 or 5, wherein the alignment is performed by using the reference mark (41t) and pressing the both while sandwiching the separator (3).   The step of obtaining the electrode preliminary body (27, 29) comprises preparing a pair of the active material films (6, 9) for the positive electrode (7) or the negative electrode (10) supported by the carrier film (41). Then, the current collector (5, 8) is sandwiched between the pair of active material films (6, 9) supported by the carrier film (41), and both the electrodes are pressure-bonded while being heated, whereby the electrode preliminary body (27, 29) and the carrier film (27, 29) on the other side so that the electrode preliminary body (27, 29) is supported only by the carrier film (41) on one side. The manufacturing method of the electrical storage apparatus (1) of Claim 7 including the sub process of removing 41). Preparing a film-like positive electrode (7) on a resin carrier film (41);
Preparing a film-like negative electrode (10) on a resin carrier film (41);
Forming fiducial marks (41t, 41t) on the carrier films (41, 41);
Bonding the positive electrode (7) and the negative electrode (10) while heating with the separator (3) interposed therebetween;
After the thermocompression bonding, removing the carrier film (41) supporting the negative electrode (10);
Another negative electrode (7) supported by the carrier film (41) is sandwiched between the other separator (3) on the surface of the negative electrode (10) from which the carrier film (41) is removed. And crimping while heating,
In the step of crimping the positive electrode (7, 7), the negative electrode (10) and the separator (3) to each other, each member is aligned based on the reference mark (41t, 41t),
The manufacturing method of the electrical storage apparatus (1) characterized by using the base material annealed after extending | stretching for the said carrier films (41, 41).   The power storage device (1) is a lithium ion polymer secondary battery (1) in which a fluororesin is used as a binder for electrodes (7, 10) and a resin microporous film is used as a separator (3). Item 10. The method for manufacturing the power storage device (1) according to any one of Items 1 to 9.

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