JP6163739B2 - Method and apparatus for manufacturing film-covered electrical device - Google Patents

Description

  The present invention relates to a manufacturing method and a manufacturing apparatus for a film-covered electrical device represented by a battery or a capacitor, in which electrical device elements are accommodated in a laminate film.

  An electric device typified by an electrolytic capacitor or a battery is manufactured by injecting an electrolytic solution into a case made of a metal or the like containing an electrode group to obtain an electric device element, and then closing the case. In the description in the present specification, a state having a positive electrode and a negative electrode laminated via a separator and in a state (stage) before completion of a series of injection steps of the electrolytic solution is referred to as an “electrode group”. In addition, a state (stage) in which a series of injection steps of the electrolytic solution is completed is distinguished as an “electric device element”.

  Conventionally, a predetermined amount of electrolytic solution is poured into a vertically standing case, and then allowed to stand for a long time, so that the electrolytic solution is gradually infiltrated into the gaps between the electrode groups. However, since the electrode group is generally formed by densely laminating electrode plates, it takes time to impregnate the gap between the electrode groups with the electrolytic solution. For example, it is necessary to leave the electrolyte solution standing still for a whole day and night until it naturally penetrates into the gap between the electrodes, and the production efficiency is extremely low.

  Further, since the impregnation rate of the electrolytic solution is extremely slow, if the necessary amount of electrolytic solution is supplied into the case at once, the electrolytic solution overflows from the case. Therefore, a method has been employed in which a cover is attached in a watertight manner to the opening of the case, and a predetermined amount of electrolyte is poured into the cover. However, this method requires time and effort for attaching covers to the case one by one, making it difficult to increase manufacturing efficiency.

  Patent Document 1 discloses a method for injecting and impregnating an electrolytic solution in order to solve such a problem. That is, the opening of the case is hermetically closed and depressurized, and the electrolytic solution is injected into the depressurized case, and the gap between the electrode groups is impregnated with the electrolytic solution. Rather than injecting the electrolyte solution and reducing the pressure, the electrolyte solution is injected after reducing the opening of the case to form a liquid reservoir. After injecting the electrolytic solution into the decompressed case and allowing the electrolytic solution to penetrate into the gap between the electrode groups, the pressure in the case is further increased to allow the accumulated electrolytic solution to penetrate into the gap between the electrode groups.

  In this method, once the pressure is reduced, the air in the gap between the electrode groups, which impedes the impregnation of the electrolyte, is removed, the electrolyte is poured into the gap, and then the electrolyte is injected. Pressure and inject the electrolyte in the reservoir. Thus, the combination of reduced pressure and increased pressure not only shortens the time required for impregnation with the electrolyte, but also prevents the electrolyte from scattering when the pressure is released.

  On the other hand, in addition to the electrical device using the metal case as described above, a laminate in which a metal layer such as aluminum and a heat-weldable resin layer are laminated on the exterior body through an adhesive layer to form a thin film A film-clad electrical device using a film-clad material has been developed. Laminate film exterior materials generally have a structure in which both surfaces of a thin metal layer such as aluminum are covered with a thin resin layer, are resistant to acids and alkalis, and are lightweight and flexible.

Japanese Patent No. 3467135

  Unlike the metal case, the laminate film exterior material of the film exterior electrical device has flexibility. That is, since the laminate film exterior material is easily deformed, there arises a problem that is not found in a metal case that is difficult to deform even when an electrolyte is injected.

  First, the electrolyte injected into the opening of the bag-shaped laminate film exterior material flows between the main surface of the electrode group and the laminate film without forming a liquid pool in the opening. Therefore, the electrode group is temporarily sealed to the outside by a liquid pool, and the electrode group is impregnated with an electrolytic solution forming a liquid pool by providing a pressure difference between the electrode group and the outside. The method disclosed in the above cannot be adopted as it is. Therefore, in a film-clad electrical device using a laminate film packaging material, as described above, it takes time to impregnate the gap between the electrode groups with the electrolytic solution. For example, it is necessary to leave the electrolyte solution standing still for a whole day and night until it naturally penetrates into the gap between the electrodes, and the production efficiency is extremely low.

  In addition, the electrolyte solution does not impregnate into the electrode group at a uniform rate, and a phenomenon (impregnation unevenness) that the electrolyte solution cannot be sufficiently impregnated easily occurs in the portion to be impregnated, particularly in the central portion of the electrode group. There is a problem. The uneven impregnation of the electrolytic solution may appear as wrinkles on the surface of the laminate film because the laminate film has flexibility.

  Further, the uneven impregnation of the electrolytic solution in the electrode group partially causes a region having low ion conduction characteristics between the positive and negative electrodes in the plane, and as a result, deteriorates the electric characteristics of the battery. Arise.

  Accordingly, the present invention provides a method for manufacturing a film-covered electrical device that is less likely to cause impregnation unevenness of the electrolyte in the electrode group, and can promote penetration and impregnation after injection of the electrolyte in a short time, and its An object is to provide an apparatus.

  In order to achieve the above object, the film-clad electrical device manufacturing method of the present invention is characterized in that it includes the following steps (1) to (3).

(1) A liquid injection chamber in a state in which a bag-like laminate film exterior material having an opening containing an electrode group having a positive electrode and a negative electrode laminated via a separator is sandwiched by pressing jigs from both sides in the thickness direction of the electrode group And a pressure reducing step for reducing the pressure in the injection chamber in which the bag-shaped laminate film exterior material is installed to a pressure lower than the atmospheric pressure.

(2) After the pressure reducing step, a liquid injection step of injecting a predetermined amount of electrolyte into the exterior material from the opening while maintaining a pressure lower than atmospheric pressure is provided .

(3) After the liquid injection step, before sealing the opening, the pressure in the liquid injection chamber is increased from a negative pressure higher than that in the liquid injection step to a range of atmospheric pressure, and after the pressurization A pressure increasing / decreasing step for reducing the pressure to a pressure lower than the pressure at the time of pressurization;

  Moreover, in order to achieve the said objective, the manufacturing apparatus of the film-clad electrical device of this invention has the characteristics in the point containing each means of the following (1)-(3).

(1) A sandwiching means for sandwiching a bag-shaped laminate film exterior material having an opening containing an electrode group having a positive electrode and a negative electrode laminated via a separator from both sides in the thickness direction of the electrode group;
Pressure adjusting means for adjusting the pressure in the liquid injection chamber in which the bag-shaped laminate film exterior material is installed in a state of being sandwiched by the sandwiching means.

  (2) It has a liquid injection means for injecting an electrolytic solution into the exterior material from the opening.

(3) The inside of the injection chamber is depressurized to a pressure lower than the atmospheric pressure by the pressure adjusting means, and after the depressurization, a predetermined amount of liquid is injected into the exterior material by the injection means while maintaining the pressure lower than the atmospheric pressure . Control means for injecting the electrolyte is provided. Further, before sealing the opening by the pressure adjusting means, the pressure in the liquid injection chamber is increased from a negative pressure higher than that during the liquid injection to a range of atmospheric pressure, and after pressurization, And a control means for reducing the pressure to a pressure lower than the pressure .

  According to the present invention, since the pressure is increased / decreased before the sealing after the injection, the impregnation of the electrolytic solution can be promoted after the injection. Since it is after the injection, the electrolyte is held in the separator, and even if the pressure is increased or decreased, no scattering occurs. As a result, it is possible to provide a method and apparatus for manufacturing a film-clad electrical device that does not cause uneven impregnation of the electrolytic solution and can permeate and impregnate the electrolytic solution in a short time after injection.

It is sectional drawing which represented typically the structure of the film-clad battery of 1st Embodiment. It is a completion perspective view showing typically the film-clad battery of a 1st embodiment. It is the disassembled perspective view which represented typically the state which decomposed | disassembled the film-clad battery of 1st Embodiment of FIG. It is a typical perspective view of the electric power generation element for demonstrating the main surface and lamination | stacking side surface of the electric power generation element in the film-clad battery of 1st Embodiment. As a typical embodiment (first embodiment) of the film-clad electrical device manufacturing apparatus of the present invention, an electrolytic solution is injected into a bag-shaped laminate film packaging material (battery cell) having an opening containing an electrode group. -It is a schematic diagram which shows the structure of the injection / impregnation apparatus for impregnation. It is drawing which shows the injection profile and the impregnation state by the injection / impregnation method of the electrolyte solution by the injection / impregnation apparatus of this embodiment. It is drawing which shows the liquid injection quantity and vacuum pressure by each liquid injection step by the liquid injection / impregnation method of the electrolyte solution by the liquid injection / impregnation apparatus of this embodiment. It is a figure which shows the mode of the bubble generation | occurrence | production at the time of liquid injection.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

FIG. 1 is a cross-sectional view schematically showing the configuration of the film-clad battery of the first embodiment. FIG. 2 is a perspective view schematically showing the film-clad battery of the first embodiment. FIG. 2 (a) is a completed perspective view of the film-clad battery, and FIG. 2 (b) is a diagram of FIG. 2 (a). It is the disassembled perspective view which represented typically the state which decomposed | disassembled the film-clad battery of 1st Embodiment for every component requirement.
(Film outer battery)
The outline | summary of a structure of the film-clad battery 10 of 1st Embodiment is demonstrated.

  As shown in FIG. 1, the film-covered battery 10 of the present embodiment has a structure in which a substantially rectangular power generation element 21 in which a charge / discharge reaction actually proceeds is sealed inside a bag-shaped laminate film that is an exterior body 29. Have Specifically, it has a power generation element 21 and an exterior body 29 made of a bag-like laminate film that houses both the positive electrode current collector 12b and the negative electrode current collector 11b provided in the power generation element 21. Furthermore, the film-clad battery 10 includes a positive electrode tab 27 connected to the positive electrode current collector 12b and a negative electrode tab 25 connected to the negative electrode current collector 11b.

  Here, in this embodiment, it has the positive electrode plate (positive electrode) 16 and the negative electrode plate (negative electrode) 14 laminated | stacked via the separator, and the state (stage) before completing a series of liquid injection processes of the electrolyte solution 20 ) Are referred to as “electrode groups”, and those in a state (stage) in which a series of liquid injection steps of the electrolytic solution 20 are completed are distinguished as “power generation elements”. The electrolytic solution 20 is mainly used for the electrolyte layer 17 constituting the power generation element 21. Specifically, the electrolyte layer 17 can be formed by impregnating the separator with the electrolytic solution 20. However, the electrolytic solution 20 does not necessarily need to be impregnated only in the separator, and is preferably impregnated in the electrode active material layers 13 and 15, and the gap between the power generation element 21 and the exterior material 29 ( It may also exist in the voids).

  As shown in FIGS. 2 (a) and 2 (b), in order to extract current from the electrodes (current collectors 11 and 12) of each layer of the power generating element 21, an electrode collector made of a metal plate (or metal foil) is used. The extension parts 11a and 12a of the electric parts 11b and 12b extend. The extending portions 11a and 12a of the electrodes (current collectors 11 and 12) of each layer are connected to the negative electrode tab 25 and the positive electrode tab 27, respectively, in the positive electrode current collecting portion 12b and the negative electrode current collecting portion 11b. Specifically, one end of each of the extending portions 11a and 12a is connected to each of the negative electrode current collector 11 and the positive electrode current collector 12, and each of the current collecting portions 11b, 12b is installed or connected. Further, the negative electrode tab 25 and the positive electrode tab 27 have a structure that is led out of the exterior material 29 so as to be sandwiched between end portions (sealing portion or seal portion 29f) of the exterior material 29 made of a bag-like laminate film. Have. The respective connections between the negative electrode tab 25 and the positive electrode tab 27, the extending portions 11a and 12a of the electrode current collectors 11b and 12b, and the negative electrode current collector 11 and the positive electrode current collector 12 of each electrode are ultrasonic welding or resistance. It is desirable to attach by welding or the like.

  In FIG. 2A and FIG. 2B, a recess 29e for accommodating the power generating element 21 is formed in an exterior material 29 made of a bag-like laminate film. A type in which four sides are sealed with a film facing each other is shown. However, the present embodiment is not limited to this, and a flat laminate film that does not form a recess may be used as the exterior material 29, or may be applied to a type in which one laminate film is folded and sealed on three sides. . Alternatively, two flat laminate films that do not form recesses may be used as the exterior material 29, or may be applied to a type in which two laminate films are overlapped to seal four sides. It is not something.

  As shown in FIG. 1, the power generation element 21 includes a plurality of substantially rectangular negative plates (negative electrodes) 14 and a plurality of positive plates (positive electrodes) 16 that are alternately arranged through a substantially rectangular electrolyte layer 17. A plurality of layers are stacked. The negative electrode plate (negative electrode) 14 includes a negative electrode current collector 11 and a negative electrode active material layer 13 formed on both surfaces of the negative electrode current collector 11. The positive electrode plate (positive electrode) 16 includes a positive electrode current collector 12 and a positive electrode active material layer 15 formed on both surfaces of the positive electrode current collector 12. The electrolyte layer 17 is formed by impregnating a porous separator (including a nonwoven fabric separator) with the electrolytic solution 20. That is, a plurality of negative electrode plates (negative electrodes) 14, electrolyte layers 17 and positive electrode plates (positive electrodes) 16 are laminated in this order, and one negative electrode active material layer 13 of the negative electrode plate 14 and one of the positive electrode plates 16 adjacent thereto are provided. One unit cell layer 19 is configured so that the positive electrode active material layer 15 faces the electrolyte layer 17. Therefore, it can be said that the film-clad battery 10 of the present embodiment has a configuration in which a plurality of single battery layers 19 are stacked and electrically connected in parallel. Note that the negative electrode active material layer 13 is disposed only on one side of the outermost layer negative electrode current collector located on both outermost layers of the power generation element 21, but the negative electrode active material layer 13 may be provided on both sides. Good. That is, instead of using a current collector dedicated to the outermost layer provided with an active material layer only on one side, a current collector having an active material layer on both sides may be used as it is as an outermost current collector. Further, by reversing the arrangement of the positive electrode and the negative electrode as compared with FIG. 1, the outermost positive electrode current collector is positioned on both outermost layers of the power generation element 21, and the outermost positive electrode current collector is disposed on one or both surfaces of the outermost layer positive electrode current collector. The positive electrode active material layer 15 may be disposed. Hereinafter, in the present embodiment, as shown in FIG. 3, the surface of the power generating element 21 viewed in the stacking direction is referred to as a main surface 21 a, and the surface viewed in the stacking direction from the lateral direction is referred to as a stacking side surface 21 b. .

  As shown in FIG. 3, each negative electrode plate 14 has a negative electrode active material layer (negative electrode) 13 applied and formed on both sides of a negative electrode current collector 11 (for example, copper foil), and each positive electrode plate (positive electrode). 16, a positive electrode active material layer (positive electrode) 15 is applied and formed on both surfaces of a positive electrode current collector 12 (for example, an aluminum foil). The negative electrode current collector 11 and the positive electrode current collector 12 extend from the stacked region. Specifically, as shown in FIG. 1 and FIG. 2B, the extension portions of the current collectors 11 and 12 where the electrode material is not applied are the extension portions 11a on the negative electrode side and the extension on the positive electrode side. The protruding portions 12a are ultrasonically welded together. Thereby, the positive electrode current collector 12b and the negative electrode current collector 11b, which are relay parts, are formed. At the same time, the connection of the negative electrode tab 25 to the negative electrode current collector 11b and the connection of the positive electrode tab 27 to the positive electrode current collector 12b are also ultrasonically welded.

  As an example, the laminate film exterior material 29 surrounds the battery element 21 from both sides in the thickness direction by folding one rectangular laminate film in half as described above. The laminate film used for the exterior material 29 is formed by laminating a heat-fusible resin layer having heat-fusibility, a metal layer (for example, aluminum foil), and an (insulating) protective layer. As an example, the outer peripheral portion (outer edge portion) of the laminate film outer packaging material 29 is formed such that the heat-fusible resin layer made of PP (polypropylene) becomes an inner layer of the film outer battery 10 of the present embodiment. A sealing part (seal part) 29f is formed by heat-sealing the heat-sealing part. Thereby, the battery element 21 accommodated is sealed (sealed or insulated). However, the laminate film exterior material 29 of the present embodiment is not limited to the above configuration, and various conventionally known laminate film exterior materials can be appropriately used.

As the electrolytic solution 20, one using 1 mol / liter of LiPF ₆ as a supporting salt and using a mixed solvent of propylene carbonate and ethylene carbonate (mass ratio 50:50) as a solvent can be used. However, the present embodiment is not limited to these. That is, the electrolytic solution 20 has a form in which an appropriate amount of a supporting salt is dissolved in a solvent. As the solvent, for example, carbonates such as dimethyl carbonate (DMC) and diethyl carbonate (DEC) can be used in addition to the above-described ethylene carbonate (EC) and propylene carbonate (PC). These may be used alone or in combination of two or more. As the supporting salt, addition of LiPF ₆ mentioned _{above, Li (CF 3 SO 2)} 2 N, Li (C 2 F 5 SO 2) 2 N, LiBF 4, LiAsF 6, LiTaF 6, LiClO 4, LiCF 3 SO ₃ or the like can be used. These may be used alone or in combination of two or more. Further, the concentration of the supporting salt may be appropriately determined in the range of about 0.5 to 2 mol / liter, but is not limited to this range.

(Film-clad battery manufacturing equipment)
Hereinafter, the configuration of the liquid injection / impregnation apparatus in the present embodiment for injecting / impregnating the electrolyte solution into the film-clad battery cell will be described with reference to the drawings.

  FIG. 4 shows a configuration of a liquid injection / impregnation apparatus for injecting / impregnating an electrolyte into a film-clad battery cell as a typical embodiment (first embodiment) of the film-clad electrical device manufacturing method of the present invention. It is a schematic diagram which shows.

  As shown in FIG. 4, the liquid injection / impregnation apparatus 1 of the present embodiment includes a liquid injection barber 2, a liquid injection magazine 3 having a holding jig 3a, an electrolyte supply line 4, an exhaust line 5, and a gas. An introduction line 6 and a control unit 7 are included.

  The control unit 7 controls the operation of the holding jig 3 a, the vacuum pump 5 b connected to the exhaust line 5, and the electrolyte storage tank 4 a connected to the electrolyte supply line 4. The operation of each unit controlled by the control unit 7 will be described in detail below.

  A liquid injection magazine 3 having a holding jig 3 a for storing a large number of battery cells 10 a in which the electrolytic solution 20 has not been injected (FIG. 4) is installed in the liquid injection bar 2. Are connected to an electrolyte supply line 4, an exhaust line 5, and a gas introduction line 6, respectively.

  The holding jig 3a provided in the liquid injection magazine 3 is a plate-shaped jig (plate member) that is installed so as to stably hold a large number of battery cells 10a that are not filled with an electrolyte. When the electrolytic solution 20 is injected from the opening 29a into the bag-shaped laminate film exterior material 29 in which the battery group 21 ′ is accommodated by the holding jig 3a, the exterior material 29 is placed in the thickness direction of the battery group 21 ′. It can be sandwiched and held from both sides (both main surfaces 21a side; see FIG. 3).

  The laminate film exterior material 29 that houses the battery group 21 ′ sandwiched between the pressing jigs 3 a is formed in a bag shape. That is, the bag-shaped laminate film exterior material 29 is heat-sealed at sides other than the upper opening 29a, and only the opening 29a is opened. This is because the opening 29a has a bag shape in which the electrolyte solution 20 can be injected into the bag-shaped laminate film outer packaging material 29 containing the battery group 21 '.

  One end of the electrolytic solution supply line 4 constituting the liquid injection means is connected to a tank 4a for storing the electrolytic solution. The other end of the electrolytic solution supply line 4 is divided into a plurality of parts on the way, and connected to the electrolytic solution transfer pump 4c for each system. The electrolyte transfer pump 4c is connected to the valve 4d. Opening and closing of the valve 4d is controlled by the control unit 7, and the opening degree is adjusted, so that the liquid can be injected in small portions several times for each system. The pump 4c and the valve 4d are installed outside the liquid injection chamber 2 and connected to each liquid injection nozzle 4b provided in the liquid injection chamber 2. The liquid injection nozzle 4b on the other end side of the electrolytic solution supply line 4 is disposed so as to correspond to the opening 29a of the laminate film exterior material 29 that opens upward. This is because the electrolytic solution 20 supplied from the electrolytic solution supply line 4 is injected from the opening 29a.

  In the present embodiment, the plurality of liquid injection nozzles 4b are sequentially movable above the openings 29a of the plurality of battery cells 10a arranged side by side. Therefore, the electrolytic solution 20 can be repeatedly supplied to the plurality of battery cells 10a sequentially by one nozzle 4b. For example, a traveling rail (not shown) provided in the liquid injection chamber 2 can be considered as a configuration that allows the liquid injection nozzle 4b to move. The liquid injection nozzle 4b can be moved along this rail.

  The exhaust line 5 constituting pressure adjusting means (mainly pressure reducing side adjusting means) mainly includes a valve 5a and a vacuum pump 5b, and is controlled so that the inside of the liquid injection chamber 2 can be evacuated to reduce pressure. Connected to the unit 7.

  A gas introduction line 6 constituting pressure adjustment means (mainly pressure-side adjustment means) introduces dry air or inert gas into the liquid injection chamber 2 evacuated by the exhaust line 5 to inject liquid. This is for increasing the internal pressure of the chamber 2 from a vacuum state or a reduced pressure state. This gas introduction line 6 mainly has a valve 6a and a gas storage tank 6b. The valve 6a and the like are provided so that the inside of the injection chamber 2 can be raised (pressurized / pressured) from a vacuum state or a reduced pressure state. It is connected to the control unit 7.

(Method for producing film-clad battery)
Next, steps included in the method for producing the film-clad battery of this embodiment will be described.

(Electrolytic solution injection / impregnation method)
Hereinafter, a method for injecting and impregnating the electrolytic solution 20 by the injecting and impregnating apparatus 1 of the present embodiment for injecting and impregnating the electrolytic solution into the film-coated battery cell will be described with reference to the drawings. FIG. 5 is a drawing showing an injection profile and an impregnation state by the injection / impregnation method of the electrolytic solution 20 by the injection / impregnation apparatus 1 of the present embodiment. FIG. 6 is a drawing showing the injection amount and the vacuum pressure in each injection step by the injection / impregnation method of the electrolytic solution 20 by the injection / impregnation apparatus 1 of this embodiment. FIG. 7 is a diagram showing how bubbles are generated during injection.

  5A to 5J are drawings showing the state in which the electrolyte is impregnated on the battery surface at the left end of the liquid injection magazine by the pressure operation after the liquid injection from the beginning to the end of the liquid injection. It is. In the figure, the portion represented in white is the portion of the uninjected liquid before the outermost separator provided on the battery surface is impregnated with the electrolytic solution. On the other hand, the portion represented in black is a portion in which the outermost separator provided on the battery surface is impregnated with the electrolytic solution. This is because, as shown in FIG. 1, electrodes are located on the normal battery surface, but in this figure, a separator is further installed on the battery surface to facilitate monitoring of the impregnation state of the electrolyte into the separator. It is a thing. Thus, in the film-clad battery of this embodiment, the form which installs a separator in the outermost layer of an electrode group is not excluded at all.

  The graphs shown in FIGS. 5 and 6 show the relationship between the injection amount and time for the battery cell 10a injected by the injection nozzle of FIG.

  FIG. 7 (a) shows an example in which the degree of pressure reduction during injection is increased to a pressure at which air expansion that impedes impregnation of the electrolytic solution occurs (as a high degree of vacuum), bubbles are generated, and the electrolytic solution is scattered. It is drawing which shows the liquid injection state. FIG. 7 (b) shows the embodiment according to the present embodiment in which the scattering of the electrolytic solution is suppressed by suppressing the generation of bubbles by suppressing the degree of decompression at the time of injection at a pressure at which air expansion that impedes the impregnation of the electrolytic solution does not occur. It is drawing which shows a liquid injection state.

  The injection / impregnation method of the electrolytic solution 20 by the injection / impregnation apparatus 1 of the present embodiment is performed from the opening 29a while maintaining the inside of the injection chamber 2 at a pressure lower than the atmospheric pressure, as shown in FIG. The entire amount of the electrolytic solution 20 having a predetermined injection amount is injected into the exterior material 29. The point in time when the entire amount of the electrolyte solution 20 of a predetermined injection amount is injected is the time indicated by a circle A in FIG. In the method for injecting and impregnating the electrolytic solution 20 according to the present embodiment, the opening 29a of the bag-shaped laminate film exterior material 29 containing the battery group 21 ′ is electrolyzed while the pressure (reduced pressure) in the injection chamber 2 is reduced. More specifically, the entire amount of the liquid 20 is injected. Specifically, as shown in FIGS. 5 and 6, the pressure (reduced pressure) is maintained between the injection steps # 1 to # 7, and electrolysis is performed according to the following procedure. The liquid 20 is injected.

(Decompression step)
As shown in FIG. 4, a plurality of battery cells 10 a are aligned in the chamber 2.

  Next, the vacuum pump 5b of the exhaust line 5 is driven through the control unit 7 with the valve 5a being opened to reduce the pressure in the liquid injection chamber 2 to a pressure lower than the atmospheric pressure. When the predetermined degree of vacuum is reached, the valve 5a is closed. In this state, the inside of the liquid injection chamber 2 including the inside of the electrode group 21 ′ is equally depressurized to a predetermined pressure. As shown in FIG. 5, in the liquid injection stage (for example, up to T1 in FIG. 5), the pressure is higher than the degree of pressure reduction during the pressure operation after the liquid injection (for example, T5, T8, T10 in FIG. 5). It is desirable to do it. This is excellent in that it can effectively prevent foaming and scattering while the electrolyte solution 20 is impregnated in the separator or the like in the liquid injection stage (FIG. 7A and FIG. 7). (See b) for comparison). As shown in FIGS. 5 and 6, the degree of decompression in the liquid injection chamber 2 may be a pressure lower than the atmospheric pressure, but is preferably within a range where the electrolytic solution 20 does not boil and become violently foamed. It is preferable to reduce the pressure to a pressure closer to vacuum. Thereby, excess air (gas) in the battery cell 10a can be expelled, the occurrence of gas accumulation can be prevented, and the electrolyte can be sufficiently impregnated. For example, the pressure is 5 kPa or less, more preferably 3 kPa or less, and particularly preferably in the range of about 1.5 to 2 kPa. However, in the present embodiment, the range is not limited at all.

  In the impregnation state in this step, as shown in FIG. 5A, the separator is not impregnated with the electrolytic solution, and the entire surface is white.

(Liquid injection process)
Next, while maintaining the inside of the liquid injection chamber 2 at the pressure achieved by the pressure reducing step (pressure lower than the atmospheric pressure), a predetermined liquid injection amount (a prescribed amount of electrolytic solution) from the opening 29 a into the exterior material 29. The whole amount of the electrolyte solution is poured.

  Specifically, a predetermined injection is performed by dividing the electrolyte solution supply line 4 through the injection nozzle 4b through the opening 29a in the upper part of the exterior material 29 in small portions (seven times in FIGS. 5 and 6). A total amount of the electrolyte solution 20 in an amount (specified electrolyte amount) is injected. The battery group 21 ′ is moderately pressed across the entire main surface of the plate member of the pressing member 3a in the thickness direction, and therefore the gap through which the electrolyte 20 flows to the central portion on the main surface 21a side of the battery group 21 ′. There is no. Further, by being pressed by the pressing member 3a, the gaps between the plurality of positive plates, separators, and negative plates constituting the electrode group 21 ′ are small, and the electrolyte 20 flows between the plurality of positive plates, separators, and negative plates. There is almost no. Furthermore, since the inside of the liquid injection chamber 2 including the inside of the battery group 21 ′ is equally reduced to a predetermined pressure, the electrolytic solution 20 is sucked into the battery group 21 ′ by the negative pressure in the battery group 21 ′. It is never done. Therefore, in the liquid injection step, the electrolyte solution 20 of a predetermined liquid injection amount (a prescribed amount of electrolyte solution) is little by little until the outer periphery of the battery group 21 ′ and the vicinity of the center are immersed in the electrolyte solution 20. The injection is performed in several times (see (a) → (b) → (d ′) in FIG. 5).

  Specifically, as shown in FIG. 5 (d ′), at the time of completion of this process, the electrolyte solution 20 is not impregnated up to the central portion on the main surface 21a side of the battery group 21 ′, and the impregnated state of the separator is also It can be seen that the central portion remains white and is not impregnated.

  In addition, as shown in FIGS. 5 and 6, the electrolytic solution 20 is injected in small portions several times in this step in order to prevent the electrolytic solution from overflowing from the outer packaging material 29 and scattering. . It takes time for the battery group 21 'to be impregnated with the electrolyte. Even if the amount of the electrolyte solution to be finally impregnated is poured all at once without being completely impregnated, it may overflow from the exterior material 29. However, the electrolytic solution 20 injected in this step does not have a gap that quickly flows even if it is injected in small portions. Therefore, while slightly bubbling on the upper side of the battery group 21 ′ (see FIG. 7 (b)), the electrode group 21 ′ gradually gradually impregnates (that is, there is a slight gap and the pressing force is difficult to be applied) from the outer peripheral portion. It can be seen that it is infiltrated (impregnated). (See (a) → (b) → (d ′) in FIG. 5). As shown in FIGS. 5 and 6, the vacuum pressure in this step is kept constant while maintaining the pressure reduced to a pressure lower than the atmospheric pressure in the previous step.

  Further, in this step, the electrolyte solution 20 of a predetermined injection amount (a prescribed amount of electrolyte) is injected into the battery cell 10a in small portions several times through the injection nozzle 4b. Specifically, as shown in the graphs of the injection profiles shown in FIGS. 5 and 6, a predetermined injection amount (a prescribed amount of electrolyte) is divided into seven steps from injection steps # 1 to # 7. The liquid is gradually poured in time.

  As shown in FIGS. 5 and 6, when one battery cell 10a is seen, after itself is injected, another battery cell 10a is injected and then injected again. Therefore, it can be seen that the state is maintained without being injected while the other battery cell 10a is being injected. By doing so, it is desirable in that the impregnation of the electrolytic solution is promoted during a certain time after each injection. However, in the present embodiment, it is not limited to the above, and the number of times of injection, the amount of injection, the time of injection, the degree of pressure reduction, etc. may be appropriately determined according to the battery size, shape, electrolyte concentration, etc. Good. For example, the number of injections is reduced as much as possible within the range that does not blow out or splash the electrolyte in large quantities, so that the amount of electrolyte can be effectively injected without waste, and the time required for electrolyte injection can be reduced. It is desirable to do. It can be said that it is desirable to increase the number of injections when increasing the number of injections depending on the pressure condition can reduce the injection time of the electrolyte.

  As described above, an optimal number of injections may be determined in the process of optimizing various conditions. Further, as shown in FIG. 6, the liquid injection amount tends to decrease as the number of liquid injection steps increases in this process. As the number of injections increases, the electrolytic solution 2 becomes less likely to be impregnated to the central portion on the main surface 21a side of the battery group 21 '. Therefore, the amount of injection is reduced as the number of injection steps increases, thereby causing scattering. Can be suppressed. The injection time can be appropriately determined from the degree of vacuum and the impregnation rate into the battery group 21 ′. As described above, the degree of vacuum is preferably set to a higher degree of vacuum within a range in which the electrolytic solution 20 can be boiled and violently bubbled and scattered. This is because the air remains in the battery cell 10a, so that the electrolytic solution cannot penetrate into the remaining air portion even at the liquid injection stage, which may cause a gas pool.

  Moreover, what is necessary is just to determine the number of battery cells and the number of liquid injection nozzles suitably. For example, the same number of battery cells 10a and injection nozzles 4b may be used, and a fixed type nozzle may be used to omit a movable mechanism or a system for controlling the mechanism, thereby reducing system trouble. Depending on the size of the liquid injection chamber 2, a plurality of liquid injection magazines may be installed in a plane, or a plurality of liquid injection magazines may be stacked three-dimensionally at appropriate intervals. Or they may be combined. As shown in FIG. 4, the liquid injection magazine 3 may have a form in which a plurality of battery cells 10 a are arranged in one row, or a form in which a plurality of battery cells 10 a are arranged in a plurality of rows. Moreover, the injection magazine 3 may be box-shaped as shown in FIG. 4 or may be circular. In the case of a circular shape, the plurality of battery cells 10a may be arranged in order in the radial direction.

  From the liquid injection steps # 1 to # 7, the amount of liquid injection at each step is gradually reduced because it is necessary to impregnate from the peripheral part of the battery group 21 ′ toward the central part as the liquid injection step proceeds. This is because the amount of liquid that can be impregnated with the electrolytic solution 20 gradually decreases. Therefore, in this step, a considerable portion of the central portion of the separator of the battery group 21 ′ remains in an uninjected state even after injecting a predetermined injection amount (specified electrolyte amount) (see FIG. 5). (See (a) → (b) → (d ′)).

Modified example of the liquid injection process Next, as a preferable modification of the liquid injection / impregnation method of the electrolytic solution 20 of the present embodiment, as the liquid injection process, while maintaining the pressure in the liquid injection chamber at the pressure after depressurization, A first injection process is performed in which a part of the electrolyte solution having a predetermined injection amount is injected into the exterior material from the opening. Thereafter, after the pressure in the liquid injection chamber is further increased to a pressure higher than the above pressure, a second liquid injection process is performed in which the pressure after the pressure increase is maintained for a certain period of time and the remainder of the predetermined liquid injection volume is injected. Hereinafter, a preferred example in which the first liquid injection process and the second liquid injection process suitable as the liquid injection process of the present embodiment are performed will be described in detail.

  The method of pouring and impregnating the electrolytic solution 20 of this modification is such that the electrolytic solution 20 is poured into the opening 29a of the bag-shaped laminate film packaging material 29 containing the battery group 21 ', and the pressure (decompression) is atmospheric pressure. The pressure is reduced between the liquid injection step # 4 and step # 5 as shown in FIGS. 5 and 6 in detail. The pressure is returned to the atmospheric pressure side (below atmospheric pressure), and the pressure is maintained for a certain period of time during the liquid injection steps # 5 to # 7. Therefore, the electrolytic solution 20 is injected by the following procedure.

(First injection process)
Next, in a preferred aspect of the present embodiment, a predetermined liquid injection is made from the opening 29a into the exterior material 29 while the liquid injection chamber 2 is maintained at the pressure achieved by the pressure reducing step (pressure lower than atmospheric pressure). A part of the electrolyte (a specified amount of electrolyte) is injected.

  Specifically, a predetermined amount of liquid injection is divided into small portions several times through the liquid supply nozzle 4b from the electrolyte solution supply line 4 through the opening 29a in the upper part of the exterior material 29 (in FIG. 5 and FIG. 6, four times). A part of the electrolyte solution 20 in an amount (a prescribed electrolyte amount) is injected. For example, as shown in the injection profiles of FIGS. 5 and 6, about 60% of the electrolyte 20 having a predetermined injection volume (a prescribed electrolyte volume) is injected.

  The battery group 21 ′ is moderately pressed across the entire main surface of the plate member of the pressing member 3a in the thickness direction, and therefore the gap through which the electrolyte 20 flows to the central portion on the main surface 21a side of the battery group 21 ′. There is no. Further, by being pressed by the pressing member 3a, the gaps between the plurality of positive plates, separators, and negative plates constituting the electrode group 21 ′ are small, and the electrolyte 20 flows between the plurality of positive plates, separators, and negative plates. There is almost no. Furthermore, since the inside of the liquid injection chamber 2 including the inside of the battery group 21 ′ is equally reduced to a predetermined pressure, the electrolytic solution 20 is sucked into the battery group 21 ′ by the negative pressure in the battery group 21 ′. It is never done. For this reason, in the first injection step, a part of the electrolyte solution 20 (about 60% of the total in FIGS. 5 and 6) having a predetermined injection amount (specified electrolyte amount) is divided into small portions and divided into several times. It is injected until the outer peripheral portion of 'is immersed in the electrolytic solution 20 (see FIG. 5B).

  Specifically, as shown in the impregnated state of FIG. 5 (b), the electrolyte solution 20 is not impregnated up to the central portion on the main surface 21a side of the battery group 21 ′ at the time of completion of this process, and the impregnated state of the separator. It can be seen that the central portion remains white and is not impregnated. In addition, as shown in FIGS. 5 and 6, the electrolytic solution is injected in small portions several times in this step in order to prevent the electrolytic solution from overflowing from the outer packaging material 29 and scattering. It takes time for the battery group 21 'to be impregnated with the electrolyte. Even if the amount of the electrolyte solution to be finally impregnated is poured all at once without being completely impregnated, it may overflow from the exterior material 29. However, the electrolytic solution 20 injected in this step does not have a gap that quickly flows even if it is injected in small portions. Therefore, while slightly bubbling on the upper side of the battery group 21 ′ (see FIG. 7A), the electrode group 21 ′ gradually gradually impregnates (that is, there is a slight gap and it is difficult to apply a pressing force) from the outer periphery. It can be seen that it is infiltrated (impregnated). (See (b) of FIG. 5). As shown in FIGS. 5 and 6, the vacuum pressure in this step is kept constant while maintaining the pressure reduced to a pressure lower than the atmospheric pressure in the previous step.

  Further, in this step, a part of the electrolyte solution 20 having a predetermined injection volume (a prescribed electrolyte volume) is injected into the battery cell 10a in small portions through the injection nozzle 4b. Specifically, as shown in the graphs of the injection profiles shown in FIGS. 5 and 6, the injection steps # 1 to # 4 are divided into four times and about 60% of the predetermined injection amount (specified electrolyte amount). Until the liquid is gradually poured.

  As shown in FIGS. 5 and 6, when one battery cell 10a is seen, after itself is injected, another battery cell 10a is injected and then injected again. Therefore, it can be seen that the state is maintained without being injected while the other battery cell 10a is being injected. By doing so, it is desirable in that the impregnation of the electrolytic solution is promoted during a certain time after each injection. However, in the present embodiment, there is no limitation on the above, and the number of times of injection, the amount of injection, the injection time, the degree of pressure reduction, etc. are appropriately determined according to the battery size, shape, electrolyte concentration, etc. do it. For example, the number of injections is reduced as much as possible within the range that does not blow out or splash the electrolyte in large quantities, so that the amount of electrolyte can be effectively injected without waste, and the time required for electrolyte injection can be reduced. It is desirable to do. It can be said that it is desirable to increase the number of injections when increasing the number of injections depending on the pressure condition can reduce the injection time of the electrolyte.

  As described above, an optimal number of injections may be determined in the process of optimizing various conditions. Further, as shown in FIG. 6, the liquid injection amount tends to decrease as the number of liquid injection steps increases in this process. For this reason, the amount that can be injected while maintaining a pressure lower than the atmospheric pressure is approximately 50 to 70%, which shortens the injection time of the electrolyte while preventing the electrolyte from being scattered. This is desirable from the viewpoint. The injection time can be appropriately determined from the degree of vacuum and the impregnation rate into the battery group. As described above, the degree of vacuum is preferably set to a higher degree of vacuum as long as the electrolyte can be prevented from boiling and violently bubbling and scattering. This is because the air remains in the battery cell 10a, so that the electrolytic solution cannot penetrate into the remaining air portion even at the liquid injection stage, which may cause a gas pool.

  Moreover, what is necessary is just to determine the number of battery cells and the number of liquid injection nozzles suitably. For example, the same number of battery cells 10a and injection nozzles 4b may be used, and a fixed type nozzle may be used to omit a movable mechanism or a system for controlling the mechanism, thereby reducing system trouble. Depending on the size of the injection chamber, a plurality of injection magazines may be installed in a plane, or a plurality of injection magazines are installed in a three-dimensional manner with appropriate intervals. These may be combined. As shown in FIG. 4, the liquid injection magazine 3 may have a form in which a plurality of battery cells 10 a are arranged in one row, or a form in which a plurality of battery cells 10 a are arranged in a plurality of rows. Moreover, the injection magazine 3 may be box-shaped as shown in FIG. 4 or may be circular. In the case of a circular shape, the plurality of battery cells 10a may be arranged in order in the radial direction.

  As described above, from the liquid injection steps # 1 to # 4, the amount of liquid injection in each step is gradually reduced from the peripheral part of the battery group 21 ′ toward the central part as the liquid injection step proceeds. This is because it is necessary to impregnate, and the amount of liquid that can be impregnated with the electrolyte 20 gradually decreases. For this reason, in the liquid injection process of the present embodiment described above, a considerable portion of the central portion of the separator of the battery group 21 ′ remains in an uninjected state even after a predetermined amount of liquid injection (a prescribed amount of electrolytic solution) is injected. (See (a) → (b) → (d ′) in FIG. 5). On the other hand, in the liquid injection process according to a preferred aspect of the present embodiment, the second liquid injection process of the next process is performed after the first liquid injection process of the present process, whereby a predetermined liquid injection amount (a prescribed amount of electrolyte) The time required to inject and impregnate can be greatly reduced. Furthermore, even after the liquid injection, the liquid injection state can be almost completely achieved up to the center of the separator of the battery group 21 ′. (Refer to FIG. 5 for comparison between the impregnation state from (a) → (b) → (c) → (d) and the impregnation state from (a) → (b) → (d ′)).

(Second injection process)
In a preferred aspect of the present embodiment, as the second liquid injection step, the pressure in the liquid injection chamber 2 is increased to a pressure higher than the pressure (pressure lower than atmospheric pressure), and then the pressure (pressure after pressure increase) is constant. Holding the time, the remaining part of the predetermined amount of electrolyte (specified amount of electrolyte) is injected (see FIGS. 5 and 6).

  Specifically, the valve 6a of the gas introduction line 6 is opened through the control unit 7, the gas is introduced into the injection chamber 2, and a pressure higher than the pressure in the injection chamber 2 (pressure lower than atmospheric pressure). Boost to. By such an operation, the main surface 21a side of the battery group 21 'is brought into the impregnated state from FIG. 5B to FIG. 5C, but no significant change is recognized. This is because the electrolyte solution 20 is not injected during this period, so there is no amount of electrolyte solution necessary for impregnation up to the central portion, and the impregnation state of the separator remains white in the central portion, and a large change can occur. It can be said that there is nothing.

  After the pressure is increased to a pressure higher than the pressure (pressure lower than atmospheric pressure), the valve 6a of the gas introduction line 6 is closed and the pressure (pressure after pressure increase) is maintained for a certain time. During this time, the remaining portion of the predetermined injection amount (specified electrolyte amount) of the electrolyte solution 20 is divided into small portions several times from the electrolyte solution supply line 4 through the injection nozzle 4b through the opening 29a in the upper part of the exterior material 29. (3 times in FIGS. 5 and 6). Specifically, as shown in the injection profiles of FIGS. 5 and 6, it can be seen that the remaining about 40% of the electrolyte solution 20 with a predetermined injection amount (a prescribed amount of electrolyte solution) is injected. By such an operation, the electrolytic solution 20 can be impregnated up to the central portion on the main surface 21a side of the battery group 21 '. Further, by injecting the entire predetermined injection amount (a prescribed amount of electrolyte), the liquid level is injected to a state above the upper end surface of the electrode group 21 '. Note that if the liquid level is below the upper end surface of the electrode group 21 ′ even if all of the predetermined liquid injection amount (the prescribed amount of electrolytic solution) is injected, the liquid injection is insufficient, and the electrode is charged during the charge / discharge process. In addition, a part of the separator may be in a dry state, which may cause a decrease in battery performance. This may be caused by the fact that a part of the electrolytic solution is scattered during the injection, so that a desired amount of the electrolytic solution cannot be injected into the battery cell 10a. Therefore, in such a case, it is desirable to inject the electrolytic solution 20 so that the liquid level is higher than the upper end surface of the electrode group 21 ′.

  As shown in FIG. 5 (d), when this step is completed, the electrolyte solution 20 is impregnated up to the central portion on the main surface 21a side of the battery group 21 ′, and the impregnated state of the separator is also a part of the central portion. Only remains white and can be sufficiently impregnated. This is because the pressure in the liquid injection chamber 2 instantaneously rises to a pressure higher than the pressure due to the introduction of the gas, but the inside of the battery group 21 ′ is still in a vacuumed state. Therefore, a pressure difference is generated between the inside of the battery group 21 ′ of the battery cell 10 a and the inside of the liquid injection chamber 2. That is, since the inside of the battery group 21 ′ is in a higher vacuum state (reduced pressure state), the electrolytic solution 20 is divided into several portions (in FIG. 5 and 6, three times) and injected. The negative pressure causes the electrolytic solution to be quickly impregnated (sucked) into the central portion of the battery group 21 ′. As a result, the impregnation property of the electrolytic solution is improved, and the injection time can be shortened. On the other hand, without increasing the pressure to a pressure higher than the pressure while maintaining the reduced pressure during the first injection step, the electrolytic solution 20 is divided into small portions several times until the point A indicated by a circle in FIG. 5 (FIG. 5). In the case of liquid injection (divided into 7 times in total), the impregnation into the central portion hardly proceeds as in the impregnation state of FIG. 5 (d ′), and a large unimpregnated portion remains in the central portion. It turns out that it becomes a result.

  In addition, when the amount of the electrolytic solution 20 is less than the amount necessary for the film-clad battery 10, this step may be repeated as an operation of injecting the solution in small portions.

  In this step, it is desirable that the pressure for holding the inside of the liquid injection chamber 2 for a certain period of time is lower than the half value of the vacuum pressure and the atmospheric pressure at the time of the first liquid injection (see FIGS. 5 and 6). That is, since it is lower than the half value of the vacuum pressure and the atmospheric pressure during the first injection, the pressure difference from the pressure during the first injection (pressure lower than the atmospheric pressure) does not become too large, and the electrolyte is scattered. Can be prevented (see FIG. 7a). However, if the pressure difference from the previous pressure (pressure lower than the atmospheric pressure) is too small, there is a possibility that a sufficient impregnation improving effect may not be obtained as shown in FIG. Specifically, it can be said that it is desirable to provide a pressure difference of at least 1 kPa or more, preferably a pressure difference of 10 kPa or more, more preferably a pressure difference of about 15 to 20 kPa. However, the preferred embodiment of the present embodiment is not limited to this range.

Moreover, in this process, you may inject | pour the electrolyte solution 20 by hold | maintaining a pressure for a fixed time in each step, raising the pressure in the injection chamber 2 in steps. Also in this case, it can be said that it is more desirable to satisfy the pressure conditions described above. This operation is excellent in that the impregnation (speed) can be promoted step by step, and the injection time can be shortened. Although this operation is not shown, for example, the pressure in the injection chamber 2 is increased stepwise from, for example, (1) 15 kPa → (2) 20 kPa → (3) 25 kPa from the pressure in the previous process. In each stage, the electrolyte solution 20 is injected while maintaining the pressure for a certain time. Here, for example, the (1) step and the pressure were maintained for _{T A} Time 15 kPa, subjected to liquid injection in small portions twice the electrolytic solution 20 in the meantime, a short _{T B} time than subsequent _{T A} The pressure is increased to the pressure in the step (2). Similarly, the (2) in step and the pressure were maintained for T _A Time 20 kPa, subjected to liquid injection in small portions twice the electrolyte 20 during this period, the subsequently T _B Time (3) Increase the pressure to the step pressure. Finally, the (3) in step and the pressure were maintained for T _A Time 25 kPa, may be performed pouring in small portions twice the electrolyte 20 therebetween. However, the preferred aspects of the present embodiment are not limited to these. From the viewpoint of increasing impregnation (speed) stepwise by increasing the pressure stepwise, the retention time and liquid injection in step (3) (= the step where the pressure difference from the previous step is maximized) It can be said that it is more effective to increase the amount (and the number of injections) than at other stages.

  In addition, as shown in FIGS. 5 and 6, the injection is divided into several times (in small portions) in both the first injection step and the second injection step, and the second injection step. It is desirable that the amount of liquid injected at each time is larger than the amount of liquid injected at the final time of the first liquid injection step. By this operation, the pressure is changed between the previous step and the main step, and the amount of liquid injection can be increased by the amount that the electrolytic solution is easily impregnated in the main step, and the injection time can be shortened. The effect finally stops the injection of the electrolytic solution 20 by the injection nozzle 4b. Specifically, the drive motors of the pumps 4c, the valves 4d, and the liquid injection nozzle 4b are stopped through the control unit 7. Thereby, a 2nd liquid injection process can be completed and the suitable aspect of the liquid injection and the impregnation method of the electrolyte solution of this embodiment can be achieved.

  As described above, in the preferred mode of the electrolytic solution pouring / impregnation method of the present embodiment, the high pressure is maintained for a certain time, so that the impregnation utilizing the pressure difference can be promoted and the pouring time is shortened. Can do. In addition, while using a flexible laminate film as an exterior material for a film-clad battery, it is possible to suppress the occurrence of wrinkles in the separator when the electrolyte solution is injected without causing a gap between the laminated surfaces.

(Operation after injection process)
Post-processing (1)
In this embodiment, as shown in FIGS. 5 and 6, as post-processing (1), after the liquid injection process, before sealing the opening, the pressure in the liquid injection chamber is changed during the liquid injection process. And pressurizing and depressurizing steps for further depressurization. Then, after performing the sealing process which seals the opening part 29a, the electrolyte solution is injected by performing the pressure | voltage rise process which returns the pressure in the injection chamber 2 to atmospheric pressure, and the film-clad battery more impregnated 10 can be obtained. The pressure increasing / decreasing step will be described.

(Pressure and decompression process)
In the pressure increasing / decreasing step, after the liquid injection step, before the opening 29a is sealed, the pressure in the liquid injection chamber 2 is increased from that in the liquid injection step, and the pressure increasing / decreasing step for further reducing the pressure is performed. Thereby, since pressure increase / decrease is performed before sealing after pouring, impregnation can be promoted. Since the electrolyte solution 20 is retained in the separator because it is after the injection, it is also excellent in that no scattering occurs even when the pressure is increased or decreased.

  For example, as shown in FIGS. 5 and 6, after the liquid injection process (see FIGS. 5D and 5D ′), before sealing the opening 29a, the pressure in the liquid injection chamber 2 is changed to the liquid injection chamber 2a. Pressurization is performed more than in the liquid step (including the first and second liquid injection steps of the preferred embodiment described above). In such an operation, the valve 6a of the gas introduction line 6 is opened through the controller 7, the gas is introduced into the injection chamber 2, and the inside of the injection chamber 2 is pressurized to a pressure higher than that in the injection step (see FIG. (See steps 5 and 6 from T1 to T2).

  In this step, when pressurizing, it is desirable to pressurize to atmospheric pressure as shown in FIGS. By pressurizing to atmospheric pressure, a large pressure difference is obtained from the time of pouring, and impregnation can be promoted. In addition, in order to return to atmospheric pressure, it is only necessary to stop evacuation, which is excellent in that the structure is simple. By such an operation, the main surface 21a side of the battery group 21 ′ is in the impregnation state of (d ′) → (e ′) in FIG. 5 to (d) → (e) in FIG. 5, and the impregnation is promoted in the central portion. It is recognized that In addition, when the modified example of the liquid injection process is adopted, the injected electrolytic solution 20 is impregnated inside the electrode group 21 ′ as in the impregnated state of FIG. As shown in FIG. 6, even by rapid pressurization (pressure increase), the impregnated electrolytic solution 20 is not scattered and can be returned to atmospheric pressure in a short time, which can contribute to shortening of the liquid injection process. .

  After injecting the electrolytic solution 20 while maintaining the pressure lower than the atmospheric pressure up to the point A of the circle shown in FIG. 5, the pressure in the injection chamber 2 is changed to the atmospheric pressure at the point B of the circle shown in FIG. In the case of returning to the above, the impregnation state shown in FIG. That is, there is no significant change from the impregnated state of FIG. 5 (d ′) at point A of the circle shown in FIG. 5, impregnation into the central part is not sufficiently promoted, and a large unimpregnated part is present in the central part. It can be seen that the remaining results are obtained.

Furthermore, when pressurizing, as shown in FIGS. 5 and 6, it is desirable to keep the pressure for a certain time (see the step of holding the atmospheric pressure for _TC time from T2 to T3 in FIGS. 5 and 6). ). Impregnation can be promoted by maintaining the pressure for a certain time during pressurization. By such an operation, the main surface 21a side of the battery group 21 ′ is brought into the impregnation state shown in FIGS. 5 (e) and 5 (e ′) to FIG. 5 (f), and the impregnation of the electrolytic solution is greatly promoted in the central portion. It is recognized that This is because the inside of the battery group 21 ′ is pressurized during this time, so that a large pressure difference is obtained from the time of injection, and impregnation of the injected electrolyte 20 into the central portion is greatly promoted. .

  In this step, after the pressurization, the pressure in the liquid injection chamber 2 is further reduced. When depressurizing, it is desirable to depressurize to a pressure lower than that at the time of liquid injection in the liquid injection process (including the first and second liquid injection processes of the above-described preferred embodiments). Such an operation is performed through the controller 7 by driving the vacuum pump 5b of the exhaust line 5 with the valve 5a opened, and in the liquid injection chamber 2 (preferably at a pressure lower than that during the liquid injection step). Until pressure is reduced. When the predetermined degree of vacuum is reached, the valve 5a is closed. In this step, since the pressure is further reduced after the pressurization, the pressure is preferably further reduced after the pressurization, compared with the time of the liquid injection. Therefore, the electrolytic solution 20 can be condensed and penetrated more than the time of the liquid injection. ing. At this time, as in the impregnation state of FIG. 5G, the electrolytic solution 20 is condensed and impregnated (impregnated) inside the electrode group 21 ′, and the impregnation is promoted to the central portion of the separator. It can be seen that the unimpregnated white portion of the portion is further reduced. Moreover, as shown in FIG. 5, even if it pressure-reduces rapidly to the pressure lower than the time of injection, the boiling of the impregnated electrolyte 20 is suppressed. For this reason, the electrolyte solution can be decompressed in a short time without scattering, and the pressurizing and depressurizing step in the present embodiment can greatly contribute to shortening the time required for impregnation after injecting the electrolyte solution. .

Further, in this step, when pressurizing and depressurizing, it is desirable to hold the pressure for a certain period of time, and to maintain the pressure holding time when pressurizing longer than the pressure holding time when depressurizing. This is because impregnation proceeds at the time of pressurization, and the impregnation can be promoted by increasing the time. More specifically, as shown in FIGS. 5 and 6, pressurization maintains a _{T C} Time atmospheric pressure until T2 to T3, short _{T D} time than _{T C} of the pressure reduction time until T4 to T5, the pouring time Holding a lower pressure. It can be seen that the time during pressurization is longer than the pressure holding time during decompression.

  Furthermore, in this step, it is desirable to repeat the pressurization and depressurization cycles a plurality of times (FIGS. 5 and 6 show an example in which three cycles are performed). Since multiple cycles are performed, the impregnation can be further promoted. Specifically, FIG. 5 (e) at the time of pressurization in the first cycle, FIG. 5 (f) after holding for a certain time, FIG. 5 (g) at the time of depressurization in the first cycle, and at the time of pressurization in the second cycle 5 (h) in FIG. 5 and FIG. 5 (i) at the time of pressurization in the third cycle, it can be seen that the impregnation of the electrolytic solution can be further promoted by performing a plurality of cycles from each impregnation state.

  In the post-step (1) step / operation, after the pressure-increasing / depressurizing step, the following sealing step and pressure-increasing step are sequentially performed to inject the electrolyte solution and obtain the impregnated film-covered battery 10 ( Can be taken out). In the post-process (1), the pressure after the pressurizing and depressurizing process is maintained instead of the pressure after the injection, or the pressure is reduced to a lower pressure (high vacuum state) within the range where the electrolyte does not boil. The opening 29a is sealed (sealed / sealed) by heat sealing. Thereafter, when the pressure is increased, the battery cells in the impregnated state shown in FIG. 5 (i) to FIG. 5 (j) are obtained.

(Sealing process)
In the sealing step, after the pressure increasing / decreasing step, the pressure is maintained (pressure at the time indicated by a circle C in FIG. 5) or lower pressure (high vacuum state) within a range where the electrolyte does not boil. In the latter case, in which the opening 29a is sealed (sealed / sealed) by heat-sealing under reduced pressure, the vacuum pump 5b of the exhaust line 5 is driven through the controller 7 with the valve 5a opened. 2 is depressurized to a lower pressure (high vacuum state) within a range where the electrolyte does not boil. When the predetermined degree of vacuum is reached, the valve 5a is closed. Next, the opening 29 a may be sealed (sealed / sealed) by thermally fusing the opening 29 a using thermocompression (fusing) means (not shown) provided in the liquid injection chamber 2.

  However, there is a peculiar phenomenon in which a relatively large amount of gas is generated in the film-covered battery 10 during the subsequent first charge / discharge (especially during the first charge), and such gas generation is mostly recognized particularly during the second and subsequent charge / discharge. Absent. Therefore, in the sealing step, a part of the opening is left to be heat-sealed and sealed, and the remaining opening is opened and closed using a detachable sealing member such as an appropriate clip. It is desirable to seal (temporarily fix). Then, after performing the first charge / discharge in the post-process, the sealing member such as the clip is removed and opened, and a relatively large amount of gas generated in the film-covered battery 10 is removed to the outside of the battery 10 (for example, reduced pressure After the removal), it is desirable that the opening is finally sealed (sealed, sealed) by thermal fusion.

(Pressure increase process)
After the sealing step, by performing a pressure increasing step for returning the pressure in the liquid injection chamber 2 to atmospheric pressure, the electrolytic solution 20 is injected and the impregnated film-clad battery 10 can be obtained (taken out). Specifically, the valve 6a of the gas introduction line 6 is opened through the control unit 7, the gas is introduced into the injection chamber 2, and the pressure in the injection chamber 2 is returned to atmospheric pressure. Thereby, the injection / impregnation method of the electrolytic solution 20 by the injection / impregnation apparatus 1 of the present embodiment can be achieved. By such an operation, the main surface 21a side of the battery group 21 ′ is in the impregnated state of FIG. 5 (i) to FIG. 5 (j). In the state, almost no white portion is observed in the central part, and the impregnated state of the separator remains white in the central part, and it can be said that no significant change has occurred.

Post-processing (3)
Furthermore, in this embodiment, as shown in FIGS. 5 and 6, as post-processing (3), after the liquid injection process, the pressure in the liquid injection chamber 2 is reduced to a pressure lower than that during the liquid injection process. You may perform the pressure reduction process after injection. Thereafter, if necessary, the pressure increasing / decreasing step similar to the post-processing (1) is performed, and the sealing step and the pressure increasing step similar to the post-processing (1) are performed to obtain a more impregnated film-covered battery 10. You can also.

(Depressurization process after injection)
In the pressure reducing step after the liquid injection, the pressure in the liquid injection chamber 2 is reduced to a pressure lower than that in the liquid injection step after the liquid injection step (including the above-described preferred mode). Since the pressure in the liquid injection chamber 2 is reduced to a pressure lower than that at the time of liquid injection, this is superior in that the electrolytic solution can be condensed and penetrated more than at the time of liquid injection. Specifically, as shown by a thick white arrow in FIG. 5, the pressure in FIG. 5 (g) (after injection) is higher than the pressure in FIG. 5 (b) (maximum negative pressure during injection). It is desirable that the maximum negative pressure is reduced to a lower pressure. In FIG. 5, the pressure may be reduced from FIG. 5 (d ′) to FIG. 5 (g) to a pressure lower than that during the liquid injection process, or from FIG. 5 (d) to FIG. 5 (g). The pressure may be reduced to a pressure lower than that. Preferably, the pressure is reduced to a pressure lower than that in the liquid injection step in FIG. 5 (d) or (d ′) → FIG. 5 (e) or (e ′) → FIG. 5 (f) → FIG. Particularly preferably, the pressure is lower than that in the liquid injection step by the solid line route of FIG. 5 (d) → FIG. 5 (e) → FIG. 5 (f) → FIG. Reduce pressure.

  In this step, the pressure in the liquid injection step (including the preferred embodiment described above) is a pressure at which air expansion that impedes impregnation of the electrolyte into the electrode group does not occur, and in the pressure reduction step after the liquid injection. The pressure is preferably a pressure at which the electrolyte does not boil. This is because the air remaining in the battery group 21 ′ is large before the injection is completed, and bubbles are generated and impregnation does not proceed if the pressure is reduced too much (see FIG. 7B). After completion of the injection, the pressure is set so that the boiling point of the electrolyte, not residual air, does not reach the working temperature. As shown in FIG. 7 (a), the pressure at which air expansion that impedes impregnation of the electrolytic solution does not occur, as long as the generation of bubbles is suppressed and the impregnation of the electrolytic solution can proceed. When the pressure is exceeded, as shown in FIG. 7 (b), it can be regarded as a pressure at which air bubbles violently occur and air expansion that impedes the electrolytic solution occurs due to scattering of the electrolytic solution. Moreover, it is not necessary to manage especially the temperature in the liquid injection chamber after completion of liquid injection from the liquid injection, and it can be carried out at room temperature (approximately in the range of 0 to 40 ° C.). Therefore, the pressure in consideration of the working temperature after completion of the pouring, which is the working temperature not exceeding the boiling point of the electrolytic solution, may be the pressure indicated by the circle C in FIG. 5 (high vacuum state). Even in the impregnated state of FIG. 5 (g) at the time of the circle C in FIG. 5, boiling of the electrolytic solution is not recognized, and it can be seen that the above requirement is satisfied. That is, it can be said that the above requirements are satisfied if the pressure is within the range from the atmospheric pressure shown in FIGS. 5 and 6 to the maximum negative pressure (pressure at the time of pressure reduction after injection such as circle C in FIG. 5).

  Moreover, in this process, as shown in FIGS. 5 and 6, the pressure in the liquid injection chamber 2 may be increased in advance after the liquid injection process and before performing this process. When pressurizing, it is desirable to pressurize to atmospheric pressure. This is because the pressure is increased to atmospheric pressure, so that a large pressure difference can be obtained from the time of pouring and the impregnation can be promoted. In addition, the structure is simple because it is only necessary to stop evacuation to return to atmospheric pressure. When the pressure is applied after the liquid injection process of a preferred embodiment by such an operation, the main surface 21a side of the battery group 21 ′ is in the impregnation state of FIG. 5 (d) to FIG. It is recognized that is promoted. During this period, the inside of the battery group 21 ′ is pressurized, so that a large pressure difference is obtained from the time of injection, and it can be said that impregnation of the injected electrolytic solution 20 into the central portion is promoted. In addition, as shown in FIG. 5 (e), the injected electrolytic solution 20 is impregnated inside the electrode group 21 ′. As shown in FIGS. 5 and 6, the impregnation is performed even by rapid pressurization (pressure increase). Thus, the electrolytic solution 20 is not scattered and can be returned to the atmospheric pressure in a short time, which can contribute to shortening of the injection process.

Further, when pressurizing (pressurizing) in advance after the liquid injection step, it is desirable to maintain the pressure for a certain period of time as shown in FIGS. 5 and 6 (large _TC time from T2 to T3 in FIGS. 5 and 6). (See the step of maintaining atmospheric pressure). Impregnation can be promoted by maintaining the pressure for a certain time during pressurization. By this operation, the main surface 21a side of the battery group 21 ′ is in the impregnation state of FIG. 5 (e) or (e ′) → FIG. 5 (f), and it is recognized that the impregnation is promoted in the central portion. . During this period, the inside of the battery group 21 'is pressurized, so that a large pressure difference is obtained from the time of pouring, and it can be said that impregnation of the poured electrolyte 20 into the central portion is promoted.

  In the depressurization step after the liquid injection in the present embodiment, as described above, the pressure in the liquid injection chamber 2 is reduced to a pressure lower than that during the liquid injection step after being pressurized as necessary. However, it goes without saying that the pressure in the liquid injection chamber can be reduced to a pressure lower than that during the liquid injection step without applying pressure after the liquid injection.

(Improved electrolyte injection)
Next, a method for injecting and impregnating the electrolytic solution 20 in the present embodiment will be described with reference to FIG. The electrolytic solution 20 is impregnated in the battery element 21 from the side of the stacked side surface 21b of the battery group 21 ′. The rectangular battery element 21 has four laminated side surfaces 21b. However, injection of the electrolytic solution 20 by effectively using all of the four laminated side surfaces 21b shortens the injection time and laminate film. This is important in preventing wrinkles from occurring on the exterior material 29. Therefore, the liquid injection nozzle 4b uniformly distributes a predetermined amount of the electrolytic solution 20 from one end to the other end of the opening 29 while traveling from one end to the other end of the opening 29 for each liquid injection. You may inject into. Furthermore, using a nozzle in which the tip of the liquid injection nozzle 4b can be tilted (moved) from right below to right and left by about 45 °, it is uniformly distributed from one end to the other end of the opening 29 for each liquid injection. Thus, a predetermined amount of the electrolytic solution 20 may be injected. However, the present embodiment is not particularly limited to these, and an existing liquid injection / impregnation method capable of uniformly liquid injection can be appropriately selected.

  As described above, the method and apparatus for manufacturing a film-clad battery and the method for injecting and impregnating an electrolytic solution into the film-clad battery cell and the apparatus thereof can achieve the following effects. . (1) Since the pressure is increased and the pressure is further reduced after the injection and before the sealing, the impregnation with the electrolytic solution can be greatly promoted. Moreover, since it is after injection, the electrolytic solution is held in the separator, and even when the pressure is increased or decreased, no scattering occurs. Further, (2) when the pressurization is performed, by increasing the pressure to atmospheric pressure, a large pressure difference can be obtained from the time of injection, and the impregnation can be promoted. To return to atmospheric pressure, it is only necessary to stop evacuation, so the structure is simple. (3) When the pressure is reduced, the pressure is reduced to a pressure (vacuum side) lower than that at the time of pouring, so that the electrolytic solution can be condensed and penetrated more than at the time of pouring. (4) When the pressure is increased and the pressure is reduced, the pressure is maintained for a certain period of time, and the pressure holding time at the time of pressurization is longer than the pressure holding time, so that the impregnation proceeds at the time of pressurization. Impregnation can be promoted by lengthening the time. (5) Impregnation can be further promoted by repeating the pressurization and depressurization cycles a plurality of times.

1 Electrolyte injection / impregnation equipment,
2 Injection chamber,
3 Injection magazine,
3a holding jig,
4 Electrolyte supply line,
4a electrolyte storage tank,
4b Injection nozzle,
4c Electrolyte supply pump on the electrolyte supply line,
4d Open / close or electrolyte flow rate adjustment valve on the electrolyte supply line,
5 Exhaust line,
5a Open / close valve for exhaust,
5b Vacuum pump for exhaust,
6 Gas introduction line,
6a Open / close on gas introduction line or gas flow rate adjustment valve,
6b gas storage tank,
7 Control unit,
10 Film-clad battery (film-clad electrical device),
10a film-clad battery cell,
11 negative electrode current collector,
11a Negative electrode (from the current collector) extension part,
11b negative electrode current collector,
12 positive electrode current collector,
12a positive electrode (from the current collector) extension part,
12b positive electrode current collector,
13 negative electrode active material layer,
14 Negative electrode plate (= negative electrode)
15 positive electrode active material layer,
16 Positive electrode plate (= positive electrode)
17 electrolyte layer (separator impregnated with electrolyte),
19 cell layer,
20 electrolyte,
20a Electrolyte droplets,
21 battery elements,
21a Main surface of the battery element,
21b Laminate side surface of battery element,
25 negative electrode tab,
27 positive electrode tab,
29 Laminate film exterior material,
29a Laminate film opening material opening,
29b Laminate film exterior material bottom,
29e Concave part of laminate film exterior material,
29f Sealing part or sealing part of laminate film exterior material.

Claims (7)

A bag-shaped laminate film exterior material having an opening containing an electrode group having a positive electrode and a negative electrode laminated via a separator is placed in the injection chamber in a state of being sandwiched by pressing jigs from both sides in the thickness direction of the electrode group. And a pressure reducing step for reducing the pressure in the injection chamber in which the bag-shaped laminate film exterior material is installed to a pressure lower than atmospheric pressure,
After the pressure reducing step, a liquid injection step of injecting a predetermined amount of electrolyte into the exterior material from the opening while maintaining a pressure lower than atmospheric pressure;
After the liquid injection step, before sealing the opening, the pressure in the liquid injection chamber is increased to a range between a negative pressure and an atmospheric pressure higher than that at the time of the liquid injection step. A pressure increasing / decreasing step of reducing the pressure to a pressure lower than the pressure at the time of pressurization.   The method for producing a film-covered electrical device according to claim 1, wherein in the pressurizing / depressurizing step, the pressure is increased to atmospheric pressure when pressurizing.   The method for producing a film-clad electrical device according to claim 1 or 2, wherein in the pressurizing and depressurizing step, the pressure is reduced to a pressure lower than that during the pouring in the pouring step.   In the pressurizing and depressurizing step, when pressurizing and depressurizing, respectively, the pressure is held for a certain time, and the holding time of the pressure when pressurizing is longer than the holding time of the pressure when depressurizing. The manufacturing method of the film-clad electrical device of any one of claim | item 1-3.   5. The method for producing a film-covered electrical device according to claim 1, wherein in the pressurizing / depressurizing step, a cycle of pressurization and decompression is repeated a plurality of times. 2. The liquid injection step of injecting at least a part of a predetermined amount of electrolyte into the exterior material from the opening while maintaining the pressure inside the liquid injection chamber at a reduced pressure. The manufacturing method of the film-clad electrical device of any one of 1 , 2, 4, 5. A sandwiching means for sandwiching a bag-like laminate film exterior material having an opening containing an electrode group having a positive electrode and a negative electrode laminated via a separator from both sides in the thickness direction of the electrode group;
Pressure adjusting means for adjusting the pressure in the liquid injection chamber in which the bag-shaped laminate film exterior material is installed in a state of being sandwiched by the sandwiching means;
Injecting means for injecting an electrolyte into the exterior material from the opening,
The pressure adjusting means reduces the pressure in the injection chamber to a pressure lower than the atmospheric pressure, and after the pressure reduction, maintains a pressure lower than the atmospheric pressure, and the liquid injection means supplies a predetermined amount of electrolyte into the exterior material. After that, before the opening is sealed by the pressure adjusting means, the pressure in the liquid injection chamber is applied to a range between a negative pressure higher than the time of the liquid injection and the atmospheric pressure. And a control means for reducing the pressure to a pressure lower than the pressure at the time of pressurization after the pressurization.