JP2005093261A - Method for manufacturing battery wrapped with laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a battery wrapped with laminated films, capable of suppressing increase of the thickness of the battery and preventing deterioration of battery characteristics and life characteristics, by preventing wrinkles in a separator from being produced in an electrolyte injecting process. <P>SOLUTION: A battery precursor 2a formed by laminating a positive electrode plate and a negative electrode plate through the separator is wrapped with two films 5, 6 so as to sandwich it, and the peripheral rim parts of the films 5, 6 are thermally fused so that one side is opened. An opening part 7 which is not thermally fused is turned upward, and electrolyte is injected in a storage part 8 from the opening part 8 so that the electrolyte infiltrates into the battery precursor 2a only from its lower end side. When injection of the electrolyte is finished, the opening part 7 is sealed by thermal fusion, and thereby this battery wrapped with the film is completed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a laminated film-clad battery in which a battery element in which a positive electrode plate and a negative electrode plate are laminated via a separator is sealed with a packaging material made of a film.

  In recent years, batteries as power sources for portable devices and the like are strongly required to be light and thin. Therefore, the battery exterior material can be further reduced in weight and thickness in place of conventional metal cans that are limited in weight and thickness, and can have a free shape compared to metal cans. As an exterior material, a material using a film is used. As the film, a laminate film obtained by laminating a metal thin film and a heat-fusible resin film is generally used.

  As a film-clad battery using a film as a packaging material, a flat battery element including a laminate in which a plurality of positive plates and a plurality of negative plates are alternately laminated via a separator and an electrolyte solution is heat-melted. It is known that the battery element is hermetically sealed (hereinafter simply referred to as sealing) by surrounding the battery element with the exterior material so that the adhesive film is on the inside and heat-sealing the exterior material around the battery element. Yes.

  A positive electrode lead terminal is connected to each positive electrode plate at a time, and a negative electrode lead terminal is connected to each negative electrode plate at a time. The positive electrode lead terminal and the negative electrode lead terminal are each extended from the exterior material. ing. The separator is made of a sheet material that can absorb a liquid, such as a microporous film or a non-woven fabric, and most of the electrolytic solution is impregnated in the separator. In addition, the laminate film is processed into a container with a hook by deep drawing so that a recess is formed when viewed from the battery element side so as not to cause wrinkles when the battery element is sealed. ing. The battery element is housed in a housing portion formed by the recess, and the laminate film is heat-sealed at the ridge around the recess.

  The film-clad battery described above is manufactured as follows.

  First, a battery precursor in which a plurality of positive plates and a plurality of negative plates are stacked via a separator is prepared. Next, a positive electrode lead terminal and a negative electrode lead terminal are connected to the battery precursor. The battery precursor to which each lead terminal is connected is sandwiched between laminate films so that each lead terminal extends from both sides in the thickness direction, and the laminate film is thermally fused around the battery precursor leaving one side. . Thereby, a laminate film is formed in the bag shape which one side opened. And electrolyte solution is inject | poured from the opening part of the laminate film formed in the bag shape, a battery precursor is impregnated with electrolyte solution, and a battery precursor is used as a battery element. Finally, the remaining one side of the laminate film is heat-sealed to seal the battery element.

  As shown in FIG. 16, the electrolyte is injected by expanding the opening with the bag-shaped laminate film 105 facing upward, and injecting the electrolyte into the storage portion by the injection nozzle 109. It is common to do. In order to efficiently manufacture a high-quality film-clad battery, it is important to smoothly impregnate the entire battery precursor 102a with the electrolytic solution in the electrolytic solution injection step.

Therefore, Patent Document 1 proposes a method in which a plate is inserted and pulled out from an opening into a bag-like laminate film before injecting the electrolytic solution, and then the electrolytic solution is injected from an injection nozzle. Yes. According to this method, since the space in the laminate film is expanded by inserting the plate, the electrolytic solution can be injected efficiently.
JP 2002-298833 A

  However, the above-described method has a problem that wrinkles may occur in the separator depending on how the electrolyte is injected. Hereinafter, this phenomenon will be described in detail.

  As shown in FIG. 17, when the electrolytic solution is injected from the upper side of the battery precursor 102a, the injected electrolytic solution hits the upper end surface of the battery precursor 102a, and then travels around the battery precursor 102a to the storage portion 108. It collects in. The flow of this electrolyte is indicated by arrows in FIG. Infiltration of the electrolytic solution into the battery precursor 102a is performed from the end face of the battery precursor in a direction perpendicular to the stacking direction of the positive electrode plate, the separator, and the negative electrode plate. Therefore, in the state shown in FIG. 17, the electrolyte directly dropped from the injection nozzle 109 soaks from the upper end surface of the battery precursor 102 a and the electrolyte accumulated in the storage portion 108 soaks from the lower end surface of the battery precursor 102 a. Come on.

  When the electrolyte solution soaks into the battery precursor 102a, the separator swells and increases in size in the region where the electrolyte solution soaks. On the other hand, the size of the separator does not change in a region where the electrolytic solution has not yet penetrated. As a result, the separator is wrinkled at the boundary between the area where the electrolytic solution is soaked and the area where it is not soaked. Since the electrolytic solution permeates from the periphery of the battery precursor 102a, finally, wrinkles remain in the central region of the battery precursor 102a.

  This is the same even when the space in the laminate film is expanded as described in Patent Document 1. In Patent Document 1, the battery precursor is biased with respect to the housing portion by inserting a plate into the housing portion, and is brought into contact with the inner wall surface of the laminate film opposite to the side on which the battery precursor is biased. It is disclosed that a liquid nozzle is inserted into a storage portion. According to this, the electrolyte supplied from the injection nozzle does not fall directly on the upper end surface of the battery precursor. However, even if this method is used, if the electrolyte level in the storage portion becomes higher than the upper end surface position of the battery precursor before the electrolyte completely soaks into the battery precursor, the same as described above. For the reason, wrinkles remain in the central region of the battery precursor.

  When wrinkles occur in the separator, unevenness due to the wrinkles is generated on the surface of the battery precursor, and the unevenness appears on the surface of the film-clad battery through the laminate film. This increases the thickness of the film-clad battery. In addition, when wrinkles occur in the separator, the distance between the positive electrode plate and the negative electrode plate is increased and the battery characteristics are deteriorated, and a part of the composition of the electrolytic solution is concentrated or deposited on the wrinkle portion. The separator is clogged, and the life characteristics of the film-clad battery are also deteriorated.

  Therefore, the present invention prevents the generation of wrinkles on the separator that occurs in the electrolyte injection process, thereby suppressing the increase in the thickness of the battery and preventing the deterioration of the battery characteristics and the life characteristics. It aims to provide a method.

In order to achieve the above object, a method for producing a laminated film-clad battery according to the present invention includes sealing a battery element in which an electrolyte is impregnated into a battery precursor obtained by laminating a positive electrode plate and a negative electrode plate via a separator with a film. A method for producing a film-clad battery,
A step of producing a battery precursor in which a positive electrode plate and a negative electrode plate are laminated via a separator, a step of preparing a film for sealing the battery precursor, and the film so as to sandwich the battery precursor. A step of producing a bag assembly having an opening that surrounds and communicates the inside and outside of the space in which the battery precursor is enclosed; and an electrolyte is injected into the space from the opening to inject the battery precursor A step of producing a battery element by impregnating the electrolytic solution into a body, and a step of sealing the battery element by sealing the opening, and in the step of producing the battery element, The precursor is impregnated with the electrolytic solution only from one direction.

  In the method for manufacturing a film-clad battery according to the present invention, a battery element is manufactured by injecting an electrolyte into a bag assembly formed with a space surrounding the battery precursor. The electrolyte is soaked from only one direction. In practice, the electrolytic solution soaks into the separator among the members constituting the battery precursor, and in the process of soaking, the separator is wrinkled at the boundary between the region soaked with the electrolyte and the region not soaked. However, since the electrolyte soaks only from one direction of the battery precursor, the position of the soot also advances in the direction of soaking of the electrolyte as the electrolyte soaks, and when the electrolyte soaks throughout the battery precursor. The moth disappears. As a result, a battery element free from wrinkles can be obtained.

  The direction in which the electrolytic solution is soaked is preferably only from the lower end side of the battery precursor. As a result, the electrolytic solution can be soaked easily and efficiently. The electrolyte solution may be infiltrated only from the upper end side of the battery precursor, but in this case, if the injection amount of the electrolyte solution per unit time is too large, the electrolyte solution overflows from the battery precursor, and the same result as before Therefore, it is necessary to inject the electrolyte with care so that the electrolyte does not overflow.

  In order to prevent the electrolyte from penetrating from the upper end side of the battery precursor, in the process of manufacturing the battery element, at least until the electrolyte is infiltrated into the entire battery precursor, the inside of the space of the bag assembly. What is necessary is just to inject | pour electrolyte solution so that the liquid level position of the inject | poured electrolyte solution may become a position lower than the upper end surface of a battery precursor.

  In the present invention, the film is formed in a shape in which a concave portion is formed as viewed from the inside to form a space for the bag assembly in a region facing the battery precursor on at least one side of the battery precursor. May be.

  In this case, a recess is formed on both sides sandwiching the battery precursor, and a film assembly having a protruding portion when viewed from the inside is formed on either side thereof. If the peripheral part is heat-sealed leaving one side and the part that is not heat-sealed is an opening, the battery precursor is pushed by the protrusion, so that the electrolyte solution is applied to the upper end surface of the battery precursor. The electrolyte solution can be injected in a state where it is difficult to apply. Further, even when the film is not provided with the protruding portion, it is difficult to apply the electrolyte to the upper end surface of the battery precursor by inclining the battery precursor and injecting the electrolyte in the step of manufacturing the battery element. The electrolyte can be injected in a state. Furthermore, in both cases where the projecting portion is provided on the film and when the projecting portion is not provided, the bag assembly itself may be inclined to inject the electrolytic solution.

  The opening serving as the electrolyte inlet may be a hole formed at a predetermined position of the film. Also, when the film is heat-sealed, leaving a part of the periphery, and the part not heat-sealed is used as the opening, the electrolyte may be injected with the opening facing upward. The electrolyte may be injected with the opening positioned at the lower end. In particular, when using the hole formed in the film as the opening, and when injecting the electrolyte in a position where the opening is located at the lower end, an air vent structure for releasing the air inside the bag assembly should be provided. Is preferred.

  In the present invention, “battery precursor” means a laminate of a positive electrode plate, a separator, and a negative electrode plate before soaking the electrolyte solution, and “battery element” means after soaking the electrolyte solution. , A laminate of a positive electrode plate, a separator, and a negative electrode plate.

  As described above, according to the present invention, the battery precursor can be impregnated with the electrolyte without leaving soot, and a battery element free from soot can be obtained. As a result, an increase in the thickness of the film-clad battery can be prevented, and the distance between the positive electrode plate and the negative electrode plate can be appropriately maintained, so that the battery characteristics can be prevented from being deteriorated. Moreover, due to clogging of the separator A decrease in battery life can also be prevented.

  Next, an embodiment of the present invention will be described.

(First embodiment)
FIG. 1 is an exploded perspective view of a film-clad battery according to a first embodiment of the present invention.

  The film-clad battery 1 according to the present embodiment includes a flat rectangular battery element 2, a positive current collector 3a and a negative current collector 3b provided on opposite sides of the battery element 2, and the battery element 2. The housing includes a positive electrode lead terminal 4a connected to the positive electrode current collector 3a, and a negative electrode lead terminal 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. Tabs are provided so as to protrude from one side of each positive electrode plate and each negative electrode plate. The tabs of the positive electrode plates and the tabs of the negative electrode plates are ultrasonically welded together, respectively, and the positive electrode current collector 3a and A negative electrode current collector 3b is formed. In order to simplify the manufacturing process, the positive electrode lead terminal 4a is connected to the positive electrode current collector 3a and the negative electrode lead terminal 4b is connected to the negative electrode current collector 3b in order to simplify the manufacturing process. Although it is preferable to carry out simultaneously with formation of this, it can also carry out by another process.

  As the battery element 2, any battery element used for a normal battery is applicable as long as it includes a positive electrode, a negative electrode, a separator, and an electrolyte. Battery elements in a typical lithium ion secondary battery include a positive electrode plate in which a positive electrode active material such as lithium-manganese composite oxide and lithium cobaltate is applied on both sides of an aluminum foil, etc., and carbon that can be doped / undoped with lithium. A negative electrode plate coated with a material on both sides of a copper foil or the like is opposed to each other with a separator interposed between them and impregnated with an electrolytic solution containing a lithium salt. In addition, the present invention is applicable to battery elements of other types of chemical batteries such as nickel metal hydride batteries, nickel cadmium batteries, lithium metal primary batteries or secondary batteries, lithium polymer batteries, and capacitor elements. is there.

  As the separator, a sheet-like member that can be impregnated with an electrolytic solution, such as a microporous film (microporous film), a nonwoven fabric, or a woven fabric made of a thermoplastic resin such as polyolefin can be used.

  The exterior body is composed of two laminated films 5 and 6 surrounding and sandwiching the battery element 2 from both sides in the thickness direction, and the battery element 2 is obtained by heat-sealing the overlapping peripheral portions of the laminate films 5 and 6. Is sealed. Laminate films 5 and 6 are processed into a container with a hook so that a concave portion is formed when viewed from the side (inside) of the battery element 2 in order to form a storage portion that is a space surrounding the battery element 2. Has been. This recess can be formed by deep drawing.

  As the laminate films 5 and 6, any film used for this type of film-coated battery can be used as long as the battery element 2 can be sealed so that the electrolyte does not leak. A laminate film in which a metal thin film layer and a heat-fusible resin layer are laminated is used. As this type of laminate film, for example, a laminate of a heat-fusible resin having a thickness of 3 μm to 200 μm on 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.

  In addition, FIG. 1 shows an example in which the exterior body is configured by heat-sealing the four sides around the battery element 2 between two laminate films 5 and 6 from both sides in the thickness direction. A configuration may be adopted in which one laminated film is folded in half to sandwich the battery element 2 and the open three sides are heat-sealed to seal the battery element 2.

  Next, the manufacturing procedure of the film-clad battery 1 of this embodiment is demonstrated.

  First, a plurality of positive electrode plates and a plurality of negative electrode plates are alternately stacked via separators, and a tab for each positive electrode plate and a tab for each negative electrode plate are collectively ultrasonically welded to each positive electrode current collector 3a and a negative electrode current collector 3b are formed to produce a battery precursor. Simultaneously with or after the formation of the positive electrode current collector 3a and the negative electrode current collector 3b, the positive electrode lead terminal 4a is connected to the positive electrode current collector 3a and the negative electrode lead terminal 4b is connected to the negative electrode current collector 3b.

  On the other hand, two rectangular laminate films 5 and 6 corresponding to the planar shape of the battery precursor are prepared as an exterior material constituting the exterior body. As shown in FIG. 2, concave portions 5a and 6a are formed in the laminated films 5 and 6 at positions facing each other, and the battery elements 2 (see FIG. 1) are formed by facing these concave portions 5a and 6a. ) Is a space surrounding the battery element 2. That is, the recesses 5 a and 6 a are formed in a region facing the battery element 2. Of the recesses 5a and 6a of the respective laminate films 5 and 6, one recess 6a is formed with a constant depth, but the other recess 5a is at the center in the short side direction when viewed from the inside. , Formed into a shape having a protruding portion protruding so that a ridge line parallel to the long side is formed.

  Next, the battery precursor to which the positive electrode lead terminal 4 a and the negative electrode lead terminal 4 b are connected is surrounded by the laminate films 5 and 6, and the positive electrode lead terminal 4 a and the negative electrode lead terminal 4 b are separated from the short sides of the laminate films 5 and 6. In the extended state, the peripheral portions of the laminate films 5 and 6 are heat-sealed on three sides excluding one long side. By heat-sealing the three sides of the laminate films 5 and 6, the battery precursor is held in a state surrounded by the laminate films 5 and 6 in the storage portion formed by the laminate films 5 and 6, and one side A bag assembly in which is opened is obtained. In the present embodiment, in this state, the laminate film 5 is not heat-sealed as shown in FIGS. 3 and 4 due to the formation of the projecting portion toward the inside in the concave portion 5a. The gap between the laminate films 5 and 6 is widened at the side, and the electrolytic solution is injected from this opening in the next step. Further, the battery precursor 2 a is pushed toward the opposite laminate film 6 by the protrusion of the laminate film 5. Thereby, the battery precursor 2a is held tilted in the bag assembly.

  Next, an electrolytic solution is injected. As shown in FIG. 5, the electrolyte has the battery precursor 2 a stored in the liquid injection nozzle 9 from above the opening 7 with the wide opening 7 of the laminate films 5, 6 facing directly above. It is injected into the storage unit 8. As described above, the battery precursor 2 a is inclined by the protrusion formed on the laminate film 5, and a large space is formed on the laminate film 5 side in the storage portion 8. Thus, even when the electrolyte is injected from the injection nozzle 9, the electrolyte is directly applied to the upper end surface of the battery precursor 2a that is one end surface in the direction perpendicular to the stacking direction of the positive electrode plate, the negative electrode plate, and the separator. The electrolytic solution can be injected without dropping.

  Here, the “upper end surface” is mainly the most vertical in the posture at the time of electrolyte injection among the end surfaces in the direction perpendicular to the stacking direction of the positive electrode plate, the negative electrode plate and the separator of the battery precursor. It means a surface located on the upper side in the direction, and does not mean an absolute specific surface. This is the same in the following description.

  The electrolytic solution injected in this way is accumulated at the bottom of the storage unit 8, and the liquid level in the storage unit 8 rises as the electrolytic solution is injected. As a result, the electrolytic solution penetrates into the battery precursor 2a only from the lower end side. In the process where the electrolyte solution soaks into the battery precursor 2a, the separator swells when the electrolyte solution soaks into the separator of the battery precursor 2a, and the separator has a boundary between the region where the electrolyte solution is soaked and the region where it is not soaked. A wrinkle occurs in the part. However, since the electrolytic solution penetrates only from the lower end side of the battery precursor 2a, the position of the soot also rises with the penetration of the electrolytic solution, and as a result, the electrolytic solution completely penetrates the battery precursor 2a. At that point, the trap will disappear.

  What is important here is that electrolysis is performed so that the liquid level of the electrolytic solution accumulated in the storage unit 8 is lower than the upper end surface of the battery precursor 2a at least until the electrolytic solution soaks into the entire battery precursor 2a. The solution is poured so that the electrolytic solution does not penetrate from the upper end surface of the battery precursor 2a.

  When the injection of the electrolytic solution is completed and the electrolytic solution is completely infiltrated into the battery precursor 2a to obtain the battery element 2 (see FIG. 1), one side of the laminate films 5 and 6 which is not heat-sealed is heat-melted. The battery element 2 is sealed by sealing, whereby the film-clad battery 1 is obtained. When sealing the battery element 2, the air in the storage portion 8 is removed as necessary. Due to the sealing of the battery element 2, the protrusion formed on one laminate film 5 is pushed by the battery element 2 from the inside. Since the laminate films 5 and 6 have flexibility and the protrusions are in close contact with the battery element 2 and become almost flat, the protrusions on the laminate film 5 hardly affect the outer shape of the film-clad battery 1.

  As described above, by injecting the electrolytic solution, the electrolytic solution soaks into the battery precursor 2a only from one direction, so that the battery precursor 2a can be soaked without leaving any wrinkles in the separator. Therefore, the surface of the obtained film-clad battery 1 is not uneven due to the separator, and the thickness of the film-clad battery 1 is not increased. Further, since the distance between the positive electrode plate and the negative electrode plate due to the separator flaw does not occur, the battery characteristics are not deteriorated, and further, the concentration or precipitation of the electrolyte composition in the battery element 2 does not occur. Further, the clogging of the separator and the deterioration of the life characteristics of the film-clad battery 1 can be prevented.

  In the present embodiment, as shown in FIG. 2, one of the two laminate films 5 and 6 in which the recesses 5a and 6a are formed is provided with a region protruding in the opposite direction to the other, As shown in FIG. 5, the battery precursor 2a is tilted by pressing this protruding region, so that the electrolyte solution is not applied to the upper end surface of the battery precursor 2a. However, in the present invention, it is not essential to provide the exterior material with a protruding region for pressing the battery precursor 2a and a recess for configuring a chamber for storing the battery precursor 2a.

  For example, as shown in FIG. 6, even in the case of the laminate films 5 and 6 in which only the recesses 5a and 6a are formed, the battery precursor 2a is brought down to one of the laminate films 5 and 6 and If the electrolytic solution is injected from the injection nozzle 9 in a tilted state, the electrolytic solution does not penetrate from the upper end surface of the battery precursor 2a even if a protruding region for pressing the battery precursor 2a is not provided in the exterior material. As such, the electrolyte can be injected. In this case, as shown in FIG. 7, if the injection nozzle 9 is inserted into the storage portion 8 and the electrolyte solution is injected with the lower end of the injection nozzle 9 positioned lower than the upper end surface of the battery precursor 2a, It is possible to more reliably prevent the electrolytic solution from directly reaching the upper end surface of the battery precursor 2a.

  Further, as shown in FIG. 8, even when one laminate film 5 is formed into a simple sheet and the recess 6a is formed only in the other laminate film 6, the battery precursor 2a is formed in the same manner as in FIG. The electrolyte solution can be injected so that the electrolyte solution does not permeate from the upper end surface of the battery precursor 2a in a state of being tilted to the laminate film 6 side where the recess 6a is formed. In this case as well, as in FIG. 7, the electrolyte can be injected with the lower end of the injection nozzle 9 positioned lower than the upper end surface of the battery precursor 2a. Moreover, in the example shown in FIG. 8, it is preferable that the depth of the recessed part 6a is substantially equal to the thickness of the battery precursor 2a. Accordingly, when the battery precursor 2a is tilted toward the concave portion 6a, the battery precursor 2a is substantially accommodated in the concave portion 6a, so that the electrolytic solution is hardly applied to the upper end surface of the battery precursor 2a.

  Regarding the posture of the bag assembly at the time of injecting the electrolytic solution, in FIGS. 5 to 8, the posture in which the opening for injecting the electrolytic solution is directed directly upward, that is, the plane including the three sides that are heat-sealed is vertical. Although an example in which the electrolytic solution is injected in a posture parallel to the direction is shown, the postures of the laminate films 5 and 6 are arbitrary as long as the electrolytic solution can be injected from the opening. For example, as shown in FIG. 9, the bag assembly is held in a posture in which the plane S including the three sides to which the laminate films 5 and 6 are heat-sealed is inclined by an angle α with respect to the vertical direction. In this posture, the liquid injection nozzle 9 is inserted into the storage portion 8 and the electrolytic solution is injected.

  In this way, by tilting and holding the bag body assembly of the laminate films 5 and 6, the battery precursor 2 a is easily biased to one side (specifically, the lower side) of the storage unit 8 due to its own weight. Become. As a result, the liquid injection nozzle 9 can be easily inserted into the storage portion 8 and the electrolytic solution can be injected from a position avoiding the upper end surface of the battery precursor 2a. In this example, depending on the position of the injection nozzle 9 and the injection amount of the electrolytic solution from the injection nozzle 9, the electrolytic solution is on the surface 2b facing the laminate film 5 which is the surface in the thickness direction of the battery precursor 2a. Fall. However, since the electrolytic solution does not permeate from the surface 2b, the electrolytic solution dropped on the surface 2b flows downward along the surface 2b and accumulates at the bottom of the storage portion 8. Therefore, the electrolytic solution does not permeate from directions other than the lower side of the battery precursor 2a. In addition, since the opening is inclined with respect to the horizontal plane by tilting the bag assembly, the injection direction of the electrolyte, in other words, the angle of the injection nozzle 9 is also in the range of 0 ° to 90 ° with respect to the horizontal plane. Therefore, the degree of freedom in designing the manufacturing equipment in the actual manufacturing process is improved.

  With respect to the openings of the laminate films 5 and 6 for injecting the electrolytic solution, FIG. 3 shows an example in which the side where the lead terminal does not extend is opened, but which side is the opening is arbitrary. . For example, as shown in FIG. 10, laminate films 5 and 6 are heat-sealed on three sides excluding one side on which one of the positive electrode and negative electrode lead terminals 4 extends, and the side on which the lead terminals 4 extend is defined. It is good also as an opening part for inject | pouring electrolyte solution. In this case, since the battery precursor (not shown) is supported by the laminate films 5 and 6 only on one side, the battery precursor can be tilted more easily when the electrolytic solution is injected.

(Second Embodiment)
FIG. 11 is a perspective view in the electrolyte solution injection process of the film-clad battery for explaining the second embodiment of the present invention. FIG. 12 is a longitudinal sectional view of a plane passing through the liquid injection pipe in the step shown in FIG. 11 and 12, the battery precursor 12a in which the positive and negative lead terminals 14 are connected to the battery precursor 12a is sandwiched between two laminate films 15 and 16, and the three peripheral edges of the laminate films 15 and 16 are sandwiched. The bag assembly after heat-sealing is shown. The heat-sealed region is indicated by hatching in FIG.

  In this embodiment, the injection hole 15a for electrolyte solution is formed previously by making a hole in one laminate film 15. The liquid injection port 15a communicates with the storage portion 18 and is provided at a position lower than the upper end surface of the battery precursor 12a in the posture at the time of electrolyte injection. Further, at the time of injecting the electrolytic solution, the bag assembly holding the battery precursor 12a is in such a posture that the side not heat-sealed faces upward so that the electrolytic solution injected into the storage portion 18 does not spill. In injecting the electrolytic solution, a liquid injection tube 19 is liquid-tightly connected to the liquid injection port 15 a, and the electrolytic solution is injected into the storage portion 18 from the liquid injection tube 19. Since the liquid injection port 15a is provided at a position lower than the upper end surface of the battery precursor 12a, the electrolyte injected from the liquid injection port 15a travels on the surface of the battery precursor 12a and the inner surface of the storage unit 18. And accumulates at the bottom of the storage portion 18.

  Further, when the electrolyte solution is injected, the sides of the laminate films 15 and 16 that are not heat-sealed are positioned above the liquid injection port 15a, and the air in the storage portion 18 is here as the electrolyte solution is injected. Therefore, the electrolyte can be injected smoothly. As described above, in the present embodiment, the side that is not thermally fused to the laminate films 15 and 16 in the electrolytic solution injecting step is not left by injecting the electrolytic solution from here, but in the storage portion 18. Since the purpose is to release air, it is not necessary to leave the entire area of one side without heat-sealing, and heat-sealing may be performed so that only a part of the side opens.

  Here, at least until the electrolyte is completely infiltrated into the battery precursor 12a, the electrolytic solution is stored at a position where the liquid level of the electrolyte accumulated in the storage portion 18 is lower than the upper end surface of the battery precursor 12a. This is the same as in the first embodiment. As a result, the electrolytic solution soaks into the battery precursor 12a only from the lower side without soaking from the upper end surface. The battery precursor 12a becomes a battery element when the electrolytic solution penetrates.

  When the injection of the electrolytic solution is completed, the injected tube 19 is separated from the injection port 15a so that the injected electrolyte does not leak, the injection port 15a is sealed, and the laminate films 15 and 16 are heat-sealed. The battery element is sealed by heat-sealing the non-side. Thereby, a film-clad battery is obtained. Either the sealing of the liquid injection port 15a or the heat fusion of the laminate films 15 and 16 may be performed first. For example, after laminating the laminate films 15 and 16 first, the position of the bag assembly is changed so that the liquid injection port 15a faces upward, and the liquid injection port 15a can be sealed. If the liquid injection pipe 19 is formed of a flexible member, the posture of the bag assembly can be easily changed with the liquid injection pipe 19 attached.

  As described above, even if the injection port is opened in the exterior material itself and the electrolyte solution is injected therefrom, the position of the injection port is appropriately set, so that the electrolyte solution to the battery precursor is The soaking can be performed only from the lower side, thereby preventing the soot from remaining on the separator of the battery precursor.

  The position of the liquid injection port 15a is not particularly limited as long as it is lower than the upper end surface of the battery precursor 12a at the time of injection of the electrolytic solution, but as the position is higher, the electrolyte injected from the liquid injection port 15a. The liquid passes through an extra path until it accumulates at the bottom of the storage unit 18. Therefore, in order to inject the electrolyte more efficiently, a liquid injection port 15a is provided at the lower end portion of the storage unit 18 in the posture at the time of injection of the electrolyte so that the electrolyte is directly injected into the bottom of the storage unit 18. It is preferable to provide it.

  In the example shown in FIGS. 11 and 12, the example in which the liquid injection port 15 a is provided by making holes in the laminate films 15 and 16 has been described. The liquid injection port can also be provided by partially performing heat fusion of the laminate films 15 and 16 at the time of forming the body assembly.

  For example, in the example shown in FIG. 13, when forming a bag assembly by heat-sealing the three edges of the laminate films 25 and 26, the heat-sealing is performed while leaving a part facing one side to be opened partially. Portions 27a and 27b are formed. As a result, in the bag assembly, a region that is not heat-sealed is formed between the heat-sealed portions 27a and 27b on the side facing the opened side. That is, the laminate films 25 and 26 are heat-sealed so as to have portions that are not heat-sealed at the opposite ends in the in-plane direction parallel to the mating surfaces of the laminate films 25 and 26, respectively. An assembly is formed. One of these non-heat-sealed portions functions as a liquid injection port 28 that communicates the inside and outside of the bag assembly, and the other functions as air venting at the time of electrolyte injection.

  As shown in FIG. 13, the electrolyte solution is injected into the bag body assembly by holding the bag body assembly with the opened side facing up and inserting a liquid injection tube (not shown) into the liquid injection port 28. In this state, the side where the liquid injection port 28 is provided is located on the lowermost side. Then, the electrolytic solution is injected from the injection pipe into the inside of the bag assembly, that is, into the storage portion (not shown). Since the liquid injection port 28 is located at the lowermost end of the bag assembly, the injected electrolyte is directed from the lower side to the upper side to the battery precursor (not shown) held in the bag assembly. The battery precursor soaked with the electrolyte becomes a battery element. Thereby, electrolyte solution can be inject | poured, without leaving a flaw in a battery element.

  When the injection of the electrolyte is completed, the injection pipe is separated from the injection port 28 so that the injected electrolyte does not leak, the injection port 28 is sealed, and the open side of the bag assembly is melted. Wear and seal the battery element. Either the sealing of the liquid injection port 28 or the heat fusion of the open side may be performed first. Further, in this example, since the liquid injection port 28 can be sealed by thermal fusion of the laminate films 25 and 26, the liquid injection port 28 is sealed by thermal fusion of the open side of the bag assembly. It can be done at the same time.

  The liquid injection port formed by partially performing heat fusion is opened when the bag assembly is formed as long as it is in a position communicating with the lower end of the storage portion in the posture of the bag assembly at the time of electrolyte injection. It can be arranged not only on the side opposite to the side that is running, but also on other sides. FIG. 14 shows an example in which a liquid injection port 38 is arranged on the side on the side in the posture at the time of electrolyte injection. As described above, even when the liquid injection port 38 is arranged on the side of the bag assembly, if the position is a position communicating with the storage unit at the lower end of the storage unit, the liquid injection port 38 is injected with liquid. By inserting a tube (not shown) and injecting the electrolyte from the injection tube, the battery precursor held in the storage unit can be soaked only in the direction from the bottom to the top as a whole. it can.

  As described above, in this embodiment, a liquid injection port is provided in the bag assembly as an additional structure, but in this embodiment as well, various modifications are made as in the first embodiment. Can do.

  For example, in the laminate film, the recesses for forming the storage portion for storing the battery element (battery precursor) may be provided in the laminate film on both sides of the battery element or may be provided only in one of them. . Moreover, when the thickness of the battery element is thin, the battery element may be sealed using the flexibility of the laminate film itself without providing the recess. In the present embodiment, unlike the first embodiment, it is not necessary to open the upper part of the bag assembly at the time of injecting the electrolytic solution. Therefore, the bulge inward as shown in FIG. 2 or the like is unnecessary. .

  Also, the side that is left without being thermally fused when forming the bag assembly may be a side where the lead terminal extends or a side where the lead terminal does not extend. In either case, at the time of injecting the electrolyte, the electrolyte is injected with the remaining side facing up without heat fusion.

(Third embodiment)
In both the first and second embodiments described above, the example in which the electrolytic solution is soaked only from the lower end side of the battery precursor has been described. However, according to the present invention, the electrolytic solution is only introduced from the upper end side of the battery precursor. It can be soaked.

  FIG. 15 shows a cross-sectional view in the electrolytic solution injection step according to the third embodiment of the present invention. As shown in FIG. 15, in this embodiment, the film pressing member 50 presses the laminate film 46 from the outside at the upper end of the battery precursor 42 a from the outside, and the laminate film 46 and the battery precursor 42 a The electrolyte solution is injected from the injection nozzle 49 in a state of being in close contact with the portion pressed by the pressing member 50.

  As a result, the injected electrolyte is blocked by the film pressing member 50 at the portion where the laminate film 46 is in close contact, and is accumulated at a position above it. The accumulated electrolyte soaks into the battery precursor 42a only from the upper end surface side of the battery precursor 42a. Thus, even if the laminated film 46 is pressed by the film pressing member 50 and the injected electrolyte solution is not directly injected into the lower end side of the battery precursor 42a, the separator is formed in the battery element soaked with the electrolyte solution. Occurrence of wrinkles can be prevented. However, in this case, it is necessary to appropriately adjust the amount of the injected electrolyte so that the injected electrolyte does not overflow from the opening of the laminate film 46.

It is a disassembled perspective view of the film-clad battery by the 1st Embodiment of this invention. It is the perspective view which looked at the laminate film shown in FIG. 1 from the surface side which mutually opposes. It is a schematic perspective view in the electrolyte solution injection | pouring process of the film-clad battery shown in FIG. It is a top view of the film-clad battery in the process shown in FIG. It is the sectional view on the AA line of FIG. It is sectional drawing equivalent to FIG. 5 which shows the example of a change of the shape of the laminate film in the 1st Embodiment of this invention. FIG. 7 is a cross-sectional view corresponding to FIG. 5 when the position of the liquid injection nozzle is changed in the example shown in FIG. 6. It is sectional drawing equivalent to FIG. 5 which shows the other example of a change of the shape of the laminate film in the 1st Embodiment of this invention. FIG. 6 is a cross-sectional view corresponding to FIG. 5, showing an example of a change in the orientation of the laminate film during electrolyte injection in the first embodiment of the present invention. It is a perspective view of the example which made the opening part for electrolyte injection in the 1st Embodiment of this invention the side which a lead terminal extends. It is a perspective view of the bag body assembly in the electrolyte solution injection | pouring process of a film-clad battery for demonstrating the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view in the plane which passes along a liquid injection pipe | tube of the bag body assembly shown in FIG. It is a perspective view of the bag assembly which shows the example of a change of the liquid injection port of the 2nd Embodiment of this invention. It is a perspective view of the bag body assembly which shows the other example of a change of the liquid injection port of the 2nd Embodiment of this invention. It is sectional drawing in the electrolyte solution injection process by the 3rd Embodiment of this invention. It is a schematic perspective view in the electrolyte solution injection | pouring process of the conventional film-clad battery. It is a longitudinal cross-sectional view for demonstrating an example of the injection | pouring state of the electrolyte solution from the injection nozzle in the electrolyte solution injection process of the conventional film-clad battery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film exterior battery 2 Battery element 2a, 12a, 42a Battery precursor 3a Positive electrode current collection part 3b Negative electrode current collection part 4,14 Lead terminal 4a Positive electrode lead terminal 4b Negative electrode lead terminal 5,6,15,16,25,26, 46 Laminated film 5a, 6a Concave portion 7 Opening portion 8, 18 Storage portion 9, 49 Injection nozzle 15a, 28, 38 Injection port 19 Injection tube 27a, 27b Thermal fusion portion 50 Film pressing member

Claims (12)

A method for producing a film-clad battery in which a battery element in which an electrolytic solution is impregnated into a battery precursor obtained by laminating a positive electrode plate and a negative electrode plate via a separator is sealed with a film,
Producing a battery precursor in which a positive electrode plate and a negative electrode plate are laminated via a separator;
Preparing a film for sealing the battery precursor;
Producing a bag assembly having an opening that surrounds the battery precursor so as to sandwich the battery precursor and communicates the inside and the outside of the space in which the battery precursor is enclosed; and
A step of producing a battery element by injecting an electrolytic solution into the space from the opening and soaking the electrolytic solution into the battery precursor;
Sealing the battery element by sealing the opening,
In the step of producing the battery element, the battery precursor is impregnated with the electrolytic solution from only one direction thereof.   The method for producing a film-clad battery according to claim 1, wherein in the step of producing the battery element, the battery precursor is impregnated with the electrolytic solution only from the lower end thereof.   The step of producing the battery element includes a position where the liquid surface position of the electrolyte injected into the space is lower than the upper end surface of the battery precursor at least until the electrolyte soaks into the entire battery precursor. The manufacturing method of the film-clad battery of Claim 2 including inject | pouring electrolyte solution so that it may become.   The step of preparing the film includes forming the space in a region facing at least one side of the battery precursor, facing the battery precursor, and having a recess formed when viewed from the inside. The manufacturing method of the film-clad battery of Claim 3 including producing a film. The step of preparing the film includes producing the film in a shape in which the concave portion is formed on both sides of the battery precursor, and a protruding portion is seen in one of the concave portions when viewed from the inside. ,And,
The process of producing the said bag body assembly includes heat-sealing the peripheral part of the said film leaving the one side, and making the part which is not heat-fused into the said opening part. A method for producing a film-clad battery.   The method for manufacturing a film-clad battery according to claim 5, wherein the step of manufacturing the bag body assembly includes tilting the battery precursor in the bag body assembly by pressing the battery precursor by the protrusion. . The step of producing the bag assembly includes heat-sealing the peripheral edge of the film, leaving one side of the film, and setting the opening not to be heat-sealed, and
The method for manufacturing a film-clad battery according to claim 4, wherein the step of manufacturing the battery element includes inclining the battery precursor and injecting an electrolytic solution.   The method for producing a film-clad battery according to claim 5, wherein the step of producing the battery element includes inclining the bag assembly and injecting an electrolytic solution.   In the step of preparing the film, the opening is provided at a position lower than the upper end surface of the battery precursor in the posture of the bag body assembly when the electrolyte is injected into the space. The manufacturing method of the film-clad battery of Claim 2 or 3 including making the hole of. The step of producing the bag assembly includes heat-sealing a peripheral portion of the film leaving a part thereof,
The method of manufacturing a film-clad battery according to claim 9, wherein the step of manufacturing the battery element includes injecting an electrolytic solution from the hole in a posture in which a portion of the film that is not thermally fused is directed upward. The step of producing the bag assembly includes heat-sealing a peripheral portion of the film leaving a part thereof; and
The step of producing the battery element includes the step of setting the opening of a portion of the film that is not heat-sealed, and placing the bag assembly in a posture in which the opening is positioned at the lower end, and supplying the electrolytic solution from the opening. The manufacturing method of the film-clad battery of Claim 2 or 3 including inject | pouring. The step of manufacturing the bag assembly includes heat-sealing the film, leaving a first portion and a second portion located at opposite ends in an in-plane direction parallel to the mating surface of the film. Including
The step of producing the battery element includes the step of placing the bag assembly in a posture in which the first portion that is not heat-sealed is directed upward, and the second portion that is not heat-sealed is the opening. The manufacturing method of the film-clad battery of Claim 11 including inject | pouring electrolyte solution as.

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