JPWO2015016032A1 - Manufacturing method of laminate type secondary battery - Google Patents

Abstract

The laminated body 18 is formed by alternately laminating the positive electrode and the negative electrode through the separator so that the positive electrode extraction terminal 3 and the negative electrode extraction terminal 4 are located on the same side of the laminated body 18, and two laminates are formed. The laminated body 18 is sandwiched between films, and the two laminated films are melted, leaving a portion that becomes an opening 31 at a position that is vertically upward when the positive electrode extraction terminal 3 and the negative electrode extraction terminal 4 are oriented in the horizontal direction. The laminated body 18 is accommodated in the container 11 made of a laminated film. Then, the container 11 is arranged so that the positive electrode extraction terminal 3 and the negative electrode extraction terminal 4 are oriented in the horizontal direction, a predetermined amount of the electrolytic solution 32 is injected from the opening 31, and pressure is applied from the outside of the container 11, or At least the inside of the container 11 is depressurized, and the liquid level of the electrolytic solution 32 is raised in a plurality of stages so that the laminate is impregnated with the electrolytic solution, and the opening 31 of the container 11 is fused and sealed.

Description

  The present invention relates to a method for manufacturing a laminated secondary battery.

  Rechargeable secondary batteries are used in hybrid cars, electric cars, electric assist bicycles, and the like.

  Some secondary batteries have a film exterior type using a flexible laminate film in which both surfaces of a metal foil are covered with an insulating resin layer as an exterior container. In a laminate type secondary battery, a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated via separators made of polyethylene, polypropylene, etc., and a laminated body is formed. Connected to positive or negative lead. And the laminated body is sealed with electrolyte solution in the container comprised with the laminate film.

  In the laminated secondary battery, there are a configuration in which the positive electrode lead and the negative electrode lead are derived from the same side sealed by the laminate film, and a configuration in which the positive electrode lead and the negative electrode lead are derived from two different sides. The manufacturing process in the case of a laminated secondary battery in which the positive electrode lead and the negative electrode lead are oriented in the same direction is as follows. First, a laminated body is formed, and the laminated body is wrapped and heat-sealed with one or two laminated films so that the positive electrode lead and the negative electrode lead are led out. However, the electrolytic solution is injected from the side of the laminated body where the extraction terminal is not located. Therefore, a part of the laminate film is not heat-sealed so that an opening for electrolyte injection is formed vertically upward with the two leads facing the horizontal direction. Then, a predetermined amount of the electrolytic solution is injected into the container formed of the laminate film from the opening for injecting the electrolytic solution with the two leads facing in the horizontal direction. And the opening for electrolyte injection of a container is also plugged up by heat fusion.

  FIG. 1A to FIG. 1C are schematic views illustrating problems of a laminated battery as an example of related art. FIG. 1A is a schematic view of the X portion of the laminate-type secondary electrons shown in FIG. 1C as viewed from the opening side for electrolyte injection, and shows the state of the extraction terminal 115. FIG. 1B is a diagram showing a difference in the impregnation rate of the electrolytic solution. FIG. 1C is a photograph showing the distribution of the electrolyte solution between the electrode and the separator after a certain period of time. The black portion is impregnated with the electrolytic solution, and the white portion is not impregnated with the electrolytic solution.

  As shown in FIG. 1A, since the lead terminals 115 and 116 of each electrode of the laminate 118 are connected to the positive and negative lead terminals 120 and 121, between the positive and negative lead terminals 115 and 116, the lead 120, It becomes small toward 121. That is, the end portions of the stacked body 118 in the Z portion of FIGS. 1B and 1C are sealed by the lead terminals 115 and 116. On the other hand, the distance between each electrode and the separator in the Y portion between the positive lead terminal 115 and the negative lead terminal 116 is substantially constant. From the above, when the laminate 118 is impregnated with the electrolytic solution, the electrolytic solution concentrates in the Y portion because the Z portion is difficult to impregnate, and the Y portion is more easily impregnated with the electrolytic solution than the Z portion. Become. Therefore, as indicated by the arrows in FIG. 1B, the impregnation rate of the electrolytic solution into the laminate 118 is different between the Y part and the Z part. Actually, as shown in the photograph of FIG. 1C, the laminate 118 is not impregnated with the electrolyte evenly in the Y portion and the Z portion. Therefore, wrinkles are likely to occur in a separator made of polyethylene, polypropylene, or the like. The wrinkles of the separator change the distance between the electrodes and cause a decrease in electrical characteristics such as deterioration of the electric capacity of the laminated secondary battery.

  Therefore, in Patent Document 1, when the electrolytic solution is injected into a container made of a laminate film, drip injection, that is, a small amount of electrolytic solution is injected into the container in a plurality of times. By injecting the electrolyte solution little by little in this way, it is possible to prevent the electrolyte solution from concentrating on a part, and thereby the electrolyte solution is uniformly impregnated into the laminate, thereby suppressing the occurrence of wrinkles in the separator.

JP 2009-146602 A

  However, in the case of the above-described method of Patent Document 1, a small amount of electrolyte is divided into a plurality of times and injected into a container made of a laminate film, so that the time required from injection of electrolyte to impregnation is long. Therefore, a problem remains in mass production of the laminate type secondary battery.

  An object of the present invention is to provide a method for manufacturing a laminate type secondary battery that solves the problem that it is difficult to shorten the time required from injection of electrolyte to impregnation.

  In the method of manufacturing a laminate type secondary battery having a laminate in which the positive electrode having the positive electrode lead terminal and the negative electrode having the negative electrode lead terminal are alternately laminated with the separator interposed therebetween, the positive electrode lead terminal The positive electrode and the negative electrode are alternately laminated via a separator so that the negative electrode lead-out terminal and the negative electrode lead-out terminal are located on the same side of the laminate and do not overlap with each other, thereby forming a laminate. Then, the laminate is sandwiched between two laminate films, and at least a portion that becomes an opening is left at a position vertically upward when the positive electrode lead terminal and the negative electrode lead terminal are oriented in the horizontal direction. The film is fused and the laminate is accommodated in a container made of a laminate film. The container is arranged so that the positive electrode extraction terminal and the negative electrode extraction terminal face in the horizontal direction, and a predetermined amount of electrolyte is injected from the opening. Then, pressure is applied from the outside of the container, or at least the inside of the container is depressurized, and the liquid level of the electrolytic solution is raised in multiple stages to impregnate the laminate with the electrolytic solution, thereby opening the container. Are fused and sealed.

  According to the present invention, the time required for the injection and impregnation of the electrolyte can be shortened, and the laminate type secondary battery can be mass-produced.

It is a figure explaining the subject of the laminated battery of an example of related technology, and is the figure which looked at the X section of the laminated secondary electron shown to FIG. 1C from the opening side for electrolyte injection. It is a figure explaining the subject of the laminated battery of an example of related technology, and is a figure which shows the difference in the impregnation rate of electrolyte solution. It is a figure explaining the subject of the laminated battery of an example of related technology, and is a photograph which shows distribution of the electrolyte solution between an electrode and a separator after progress for a certain time. It is a schematic block diagram of the positive electrode in one Embodiment of a laminate type secondary battery. It is a schematic block diagram of the separator in one Embodiment of a laminate type secondary battery. It is a schematic block diagram of the negative electrode in one Embodiment of a laminate type secondary battery. It is a schematic block diagram of one embodiment of a laminate type secondary battery. It is the schematic which shows a mode that electrolyte solution is inject | poured into a container. It is the schematic explaining the 1st step of the raising process of a liquid level. It is the schematic explaining the 2nd step of the raise process of a liquid level. It is the schematic explaining the 3rd step of the raise process of a liquid level. It is the schematic for demonstrating the 1st method of pressurizing a container, and has shown the state which inserted the 1st spacer of the height which does not exceed a negative electrode extraction terminal in the accommodating member. It is the schematic for demonstrating the 1st method of pressurizing a container, The 2nd spacer of the height between drawer terminals is inserted in the accommodation member, and the state is shown. It is the schematic for demonstrating the 1st method of pressurizing a container, and has shown the state which inserted the 3rd spacer of the height exceeding a positive electrode extraction terminal in the accommodating member.

  Details of embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the same number is attached | subjected to the structure which has the same function in an accompanying drawing, and the description may be abbreviate | omitted.

  2A to 2D are schematic configuration diagrams of an embodiment of a laminated secondary battery. FIG. 2A is a positive electrode, FIG. 2B is a separator, FIG. 2C is a negative electrode, and FIG. 2D is a laminated secondary battery. is there.

  The positive electrode 13 is provided with a positive electrode extraction terminal 3, and the negative electrode 14 is provided with a negative electrode extraction terminal 4. As the sheet-like separator 5, for example, a microporous film made of a synthetic resin such as polyethylene or polypropylene is used.

  The positive electrode 13 and the negative electrode 14 described above are alternately stacked with the separator 15 interposed therebetween, thereby forming a stacked body 18. At this time, the positive electrode 13 and the negative electrode 14 are laminated so that the positive electrode extraction terminal 3 and the negative electrode extraction terminal 4 face the same direction. That is, the positive electrode extraction terminal 3 and the negative electrode extraction terminal 4 are located on the same side of the laminate 18. However, it is necessary to prevent the positive electrode extraction terminal 3 and the negative electrode extraction terminal 4 from overlapping each other. This is to prevent the positive electrode extraction terminal 3 of the positive electrode 13 and the negative electrode extraction terminal 4 of the negative electrode 14 from contacting and short-circuiting.

  The positive electrode lead terminal 3 of each positive electrode 13 is connected to the positive electrode lead 23, and the negative electrode lead terminal 4 of each negative electrode 14 is connected to the negative electrode lead 24.

  The laminated body 18 is sealed in a container 11 composed of one or two flexible laminate films in which both surfaces of a metal foil such as an aluminum foil are covered with a resin layer together with an electrolytic solution. At this time, the positive electrode lead 23 and the negative electrode lead 24 are led out from the container 11. The laminated secondary battery 25 is configured as described above. In the following description, an example in which two laminate films are used will be described.

  Next, a method for manufacturing the laminate type secondary battery 25 will be described. First, a predetermined number of the positive electrode 13 and the negative electrode 14 are laminated via the separator 15 so that the positive electrode extraction terminal 3 and the negative electrode extraction terminal 4 face in the same direction, thereby forming a laminate 18. Then, the positive electrode extraction terminal 3 of each positive electrode 13 is connected to the positive electrode lead 23, and the negative electrode extraction terminal 4 of each negative electrode 14 is connected to the negative electrode lead 24.

  Next, the laminate 18 is sandwiched between two laminate films. And two laminated films are heat-seal | fused and the laminated body 18 is accommodated in the container 11 which consists of laminated films. However, the positive electrode lead 23 and the negative electrode lead 24 are led out from the laminate film, that is, the container 11. Moreover, since it is necessary to provide the opening 31 for electrolyte injection in the part which turns to the vertical direction when the positive electrode lead 23 and the negative electrode lead 24 have faced the horizontal direction, this part is not heat-sealed.

  Next, as shown in FIG. 3, the container 11 is arranged so that the opening 31 faces vertically upward, and a predetermined amount of electrolyte solution 32 is injected into the container 11 from the opening 31.

  Next, by pressurizing the container 11 from the outside or reducing the pressure inside the container 11, the liquid level of the electrolytic solution 32 in the container 11 is raised, and the laminate 18 is impregnated with the electrolytic solution. In the present invention, the liquid level is raised in multiple steps. 4A to 4C are schematic views for explaining the liquid level raising process. 4A is the first stage, FIG. 4B is the second stage, and FIG. 4C is the third stage.

  First, in the first stage, the liquid level of the electrolytic solution 32 is raised to a position (first position A) that does not exceed the extraction terminal positioned below in the vertical direction, in this embodiment, the negative electrode extraction terminal 4. In the second stage, the liquid level of the electrolytic solution 32 is raised to a position between the extraction terminals 3 and 4 (second position B). In the third stage, the liquid level of the electrolytic solution 32 is raised to a position (third position C) exceeding the extraction terminal positioned upward in the vertical direction, in this embodiment, the positive electrode extraction terminal 3. As described above, the liquid level of the electrolytic solution 32 is raised every time a predetermined time is passed, so that the portion of the laminate 18 that is easily impregnated with the electrolytic solution 32 (in FIGS. 1A and 1B). The laminated body 18 can be impregnated with the electrolytic solution 32 in a portion (Y portion) and a portion that is difficult to impregnate (Z portion in FIGS. 1A and 1B). That is, in the first stage, since the liquid level does not reach between the lead terminals 3 and 4 which are easily impregnated with the electrolytic solution 32, the impregnation of the electrolytic solution into the laminate 18 is performed almost uniformly. In the second stage, it reaches between the lead terminals 3 and 4 that are easily impregnated with the electrolyte solution 32, but in the negative electrode lead terminal 4 portion of the laminate 18 that is already impregnated with the electrolyte solution 32 in the first stage. Since it is impregnated, there is no significant difference in the ease of impregnation. In the third stage, since the gaps between the lead terminals 3 and 4 of the laminate 18 that are already easily impregnated with the electrolytic solution 32 in the second stage are impregnated, there is no significant difference in the ease of impregnation. . From the above, unlike the related art, in the present invention, the electrolytic solution 32 is not concentrated at a specific place, so that the laminated body 18 is uniformly impregnated with the electrolytic solution 32. Therefore, wrinkles generated in the separator 15 can be suppressed.

  A method for raising the liquid level of the electrolytic solution 32 will be specifically described. In the first method of raising the liquid level of the electrolytic solution 32, the container 11 is pressurized by sandwiching the container 11, and the liquid level of the electrolytic solution 32 in the container 11 is raised. The schematic for demonstrating the 1st method of pressurizing the container 11 to FIG. 5A-FIG. 5C is shown. For example, a pressurizing member 43 having an accommodating member 41 capable of accommodating the container 11 and a spacer 42 is used. First, the container 11 into which the electrolytic solution 32 is injected is placed in the housing member 41. In the example of FIG. 5A, the first spacer 42a having a height not exceeding the negative electrode extraction terminal is inserted into the housing member 41, and the container 11 is sandwiched between the housing member 41 and the first spacer 42a and pressurized. The liquid level of the electrolytic solution 32 is raised to the first position A (see FIGS. 4A and 5A). Next, in place of the first spacer 42a, a second spacer 42b larger than the first spacer 42a and having a height between the lead terminals 3 and 4 in the example of FIG. 5B is inserted into the housing member 41. Then, the liquid level of the electrolytic solution 32 is raised to the second position B by sandwiching and pressurizing the container 11 between the housing member 41 and the second spacer 42b (see FIGS. 4B and 5B). Next, in place of the second spacer 42b, a third spacer 42c larger than the second spacer 42b, which is higher than the positive electrode lead terminal 3 in the example of FIG. And the third spacer 42c sandwiching and pressurizing the container 11 raises the liquid level of the electrolytic solution 32 to the third position C (see FIGS. 4C and 5C).

  In the second method of raising the liquid level of the electrolytic solution 32, the inside of the container 11 in the atmospheric atmosphere is decompressed by a pump or the like through the opening 31, thereby sucking up the electrolytic solution 32 and raising the liquid level. At this time, in consideration of the components of the electrolytic solution 32, the size of the container 11, and the like, the interior of the container 11 is decompressed in three stages, so that the first position A, the second position B, the first The liquid level of the electrolytic solution 32 can be raised to the position C of 3.

  In the third method of raising the liquid level of the electrolytic solution 32, the container 11 into which the electrolytic solution 32 has been injected is placed in a chamber, and the inside of the laminated body 18 is evacuated by depressurizing the inside of the laminated body. Pressure. Therefore, the liquid level of the electrolytic solution 32 rises. The pressure in the chamber may be determined in consideration of the components of the electrolytic solution 32, the size of the container 11, the size of the stacked body 18, and the like.

  Any means may be used as long as the liquid level of the electrolytic solution 32 can be changed stepwise from the first position A to the third position C.

  After the above impregnation step, the opening 31 of the container 11 made of two laminated films is closed by heat sealing or the like.

  In the laminated secondary battery 25 completed through the above steps, wrinkles of the separator 15 are suppressed, so that the distance between the electrodes is uniform, and deterioration of electrical characteristics such as deterioration of electric capacity is prevented. be able to. Further, since it is only necessary to inject the electrolytic solution 32 into the container 11 once, the time required from the injection of the electrolytic solution 32 to the impregnation can be shortened as compared with Patent Document 1 of the related art. Therefore, the present invention can contribute to mass production of the laminate type secondary battery 25.

  Further, it is not necessary to inject the entire amount of the predetermined electrolytic solution 32 into the container 11 at a time, while the liquid level of the electrolytic solution 32 is raised from the first position A to the second position B, or 2, the amount of the electrolyte solution 32 may be adjusted by injecting the electrolyte solution 32 while being raised from the position B to the third position C.

  Furthermore, in the above description, the liquid level of the electrolytic solution 32 is raised in three stages, but the liquid level of the electrolytic solution 32 may be raised in four or more stages.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2013-159374 for which it applied on July 31, 2013, and takes in those the indications of all here.

3 Positive Electrode Lead Terminal 4 Negative Electrode Lead Terminal 11 Container 13 Positive Electrode 14 Negative Electrode 15 Separator 18 Laminate 25 Laminated Secondary Battery 31 Opening 32 Electrolyte

Claims (7)

The positive electrode extraction terminal of the positive electrode and the negative electrode extraction terminal of the negative electrode are located on the same side of the laminate in which the positive electrode and the negative electrode are alternately stacked with a separator interposed therebetween, and do not overlap each other. A step of alternately laminating positive electrodes and negative electrodes through the separator, and forming the laminate;
The laminate is sandwiched between laminate films, and the laminate film is fused, leaving at least an opening portion at a position that is vertically upward when the positive electrode terminal and the negative electrode terminal are horizontally oriented. And storing the laminate in a container made of the laminate film;
Arranging the container so that the positive electrode extraction terminal and the negative electrode extraction terminal are horizontally oriented, and injecting a predetermined amount of electrolyte from the opening;
Applying the pressure from the outside of the container, or depressurizing at least the inside of the container, and increasing the liquid level of the electrolytic solution in multiple stages to impregnate the laminate with the electrolytic solution; ,
Fusing and sealing the opening of the container.   2. The method for manufacturing a laminated secondary battery according to claim 1, wherein in the step of increasing the liquid level of the electrolytic solution and impregnating the electrolytic solution, the liquid level of the electrolytic solution is increased in three stages. . The three steps are:
A first stage in which the liquid level of the electrolyte is raised to a position not exceeding a drawer terminal located below in the vertical direction among the positive electrode lead terminal and the negative electrode lead terminal;
A second step of raising the liquid level of the electrolyte to a position between the positive electrode extraction terminal and the negative electrode extraction terminal;
3. The method for manufacturing a laminated secondary battery according to claim 2, comprising: a third stage in which the liquid level of the electrolytic solution is raised to a position exceeding a drawer terminal located above in the vertical direction.   The method for manufacturing a laminated secondary battery according to any one of claims 1 to 3, wherein the container is pressurized by sandwiching the container.   The method for manufacturing a laminated secondary battery according to claim 1, wherein the inside of the container is depressurized through the opening.   The method for manufacturing a laminated secondary battery according to any one of claims 1 to 3, wherein the container is disposed in a chamber and the pressure in the chamber is reduced.   In the step of impregnating the electrolytic solution by raising the liquid level of the electrolytic solution, the amount of the electrolytic solution is adjusted by adding the electrolytic solution before the step of raising the liquid level. The manufacturing method of the lamination-type secondary battery of any one of these.

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