JP2018006261A - Method of manufacturing secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing secondary battery in which entry of foreign matter into the battery case is suppressed, when raising to atmospheric pressure after drying treatment by reduced pressure.SOLUTION: In a state where an electrode body 12 is housed in a battery case 11, and electrolyte is not yet injected, an assembly 101 is placed in a vacuum drying furnace 20, and the interior thereof is brought into temperature rising decompression state, thus drying the assembly 101. After drying the assembly 101, in a state where a nozzle 26 having an external-diameter smaller than the bore diameter of the liquid injection port 19 of the assembly 101 is inserted thereinto, air is fed to the assembly 101 via the nozzle 26 from the outside of the vacuum drying furnace 20.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a method for manufacturing a secondary battery. More specifically, the present invention relates to a method for manufacturing a secondary battery including a step of drying the inside of a battery case by decompression and heating.

  Conventionally, for example, a lithium ion secondary battery configured by sealing a battery case with an electrode body in which a positive electrode plate and a negative electrode plate are wound through a separator, and a nonaqueous electrolyte solution There is. When manufacturing such a secondary battery, after the electrode body is inserted into the battery case, a process of drying the inside of the battery case by heating may be performed before pouring the non-aqueous electrolyte. For example, Patent Document 1 describes a process of heating under reduced pressure in the process of drying the inside of a battery case.

Japanese Patent Laid-Open No. 2006-81758

  However, the conventional technique described above has the following problems. That is, no consideration is given to a process for increasing the pressure in the drying furnace to return to atmospheric pressure after the drying process by heating under reduced pressure is completed. There is a possibility that foreign matter such as metal powder may be present inside the drying furnace when it is brought together with the workpiece and the jig holding the workpiece, or is generated by rubbing between the jig and the plate on which the workpiece is placed. is there. When the inside of the drying furnace is inadvertently flowed into the drying furnace after the drying process is finished, if foreign air is inadvertently flowed into the drying furnace, the foreign matter in the drying furnace moves on the air flow and moves into the battery case. There is a risk of being inhaled.

  The present invention has been made to solve the above-described problems of the prior art. That is, an object of the present invention is to provide a method for manufacturing a secondary battery that suppresses the entry of foreign matter into the battery case when the pressure is increased to atmospheric pressure after the drying process under reduced pressure.

  One aspect of the present invention made for the purpose of solving this problem is a method of manufacturing a secondary battery having an electrode body including a positive electrode plate and a negative electrode plate, and an electrolyte solution in a battery case, An arrangement step in which the assembly in which the electrode body is housed in the battery case and the electrolytic solution is not injected is disposed in a vacuum drying furnace, and the assembly is disposed. A drying step for drying the assembly by raising the temperature inside the vacuum drying furnace and reducing the pressure; and a step for increasing the pressure inside the vacuum drying oven after drying the assembly; In the pressurizing step, in a state where a nozzle having an outer diameter smaller than the inner diameter of the liquid injection port is inserted into the liquid injection port which is an opening for injecting the electrolytic solution in the assembly, From the outside of the vacuum drying oven through the nozzle It is characterized by flowing the air to the assembly.

  According to the above aspect, in the pressurizing step, the nozzle is inserted into the liquid injection port of the dried assembly, and air flows from the outside of the vacuum drying furnace through the nozzle. Since the outer diameter of the nozzle is smaller than the inner diameter of the liquid injection port, the air flowing into the assembly from the nozzle flows out between the nozzle and the liquid injection port to the outside of the assembly. In other words, the main flow of air in the assembly is the inflow from the nozzle and the outflow between the nozzle and the liquid injection port, and the air flows in the direction from the inside of the vacuum drying furnace into the assembly. The flow of is suppressed. Therefore, even if there is a foreign substance floating in the vacuum drying furnace, the entry of the foreign substance into the battery case is suppressed.

  According to the method for manufacturing a secondary battery of the present invention, the entry of foreign matter into the battery case is suppressed when the pressure is increased to atmospheric pressure after the drying process under reduced pressure.

It is a perspective view which shows the example of the secondary battery manufactured with the manufacturing method of this form. It is a schematic sectional drawing which shows the vacuum drying furnace of a 1st form. It is explanatory drawing which shows a nozzle. It is a perspective view which shows the state which restrained the assembly with the restraining jig. It is process drawing which shows the manufacturing process using the vacuum drying furnace of a 1st form. It is explanatory drawing which shows the example of the flow of the air at the time of pressure | voltage rise. It is explanatory drawing which shows the example of the flow of the air when not implementing this invention. It is a schematic sectional drawing which shows the vacuum drying furnace of a 2nd form. It is explanatory drawing which shows the movement of a nozzle. It is process drawing which shows the manufacturing process using the vacuum drying furnace of a 2nd form.

  Hereinafter, two embodiments embodying the manufacturing method of the present invention will be described in detail with reference to the accompanying drawings. In these embodiments, the present invention is applied to a method for manufacturing a sealed lithium ion secondary battery in which an electrode body and an electrolytic solution are sealed in a metal case.

  A secondary battery 100 manufactured by the manufacturing method of the present invention is a sealed battery in which an electrode body 12 and an electrolytic solution are enclosed in a battery case 11 as shown in FIG. The battery case 11 of the secondary battery 100 is a flat rectangular box made of metal. As the electrolytic solution, a non-aqueous electrolytic solution containing lithium salt or an ion conductive polymer is suitable.

  The electrode body 12 of the secondary battery 100 is a wound body in which a strip-shaped positive electrode plate and a strip-shaped negative electrode plate are wound with a strip-shaped separator interposed therebetween. The positive electrode plate has a positive electrode active material layer formed on both sides of an aluminum foil. The positive electrode active material layer contains a positive electrode active material capable of occluding and releasing lithium ions. For example, a lithium-containing metal oxide kneaded with a binder and a dispersion solvent is preferable. The negative electrode plate has a negative electrode active material layer formed on both sides of a copper foil. The negative electrode active material layer preferably contains a carbon material such as graphite.

  As shown in FIG. 1, the battery case 11 of the secondary battery 100 has a substantially rectangular parallelepiped case main body 14 having an opening on one surface and a lid member 15 that closes the opening surface. The case body 14 and the lid member 15 are formed of, for example, an aluminum plate having a thickness of about 1 mm. The case main body 14 and the lid member 15 are fixed to each other by being welded around the entire circumference of the lid member 15 without a gap.

  A positive electrode terminal 16 and a negative electrode terminal 17 are provided at both ends in the longitudinal direction of the lid member 15 so as to protrude upward in FIG. The positive electrode terminal 16 is connected to the positive electrode plate of the electrode body 12 inside the battery case 11. The negative electrode terminal 17 is connected to the negative electrode plate of the electrode body 12 inside the battery case 11. The arrangement of the positive terminal 16 and the negative terminal 17 may be reversed.

  Further, an oval safety valve 18 and a substantially circular liquid injection port 19 are formed near the center of the lid member 15 in the longitudinal direction. The safety valve 18 is not a through-hole, and is a location where the thickness is formed thinner than other locations. When the internal pressure of the battery case 11 exceeds the valve opening pressure of the safety valve 18, the safety valve 18 is ruptured and opened, and gas or the like that increases the internal pressure is released to the outside.

  The liquid injection port 19 is a through hole formed through the lid member 15. At the time of manufacturing the secondary battery 100, an electrolytic solution is injected into the battery case 11 through the injection port 19. In the completed secondary battery 100, as shown in FIG. 1, the liquid injection port 19 is sealed with a sealing plug 191. For example, a plug 191 is inserted into the liquid injection port 19, and the periphery of the seal 191 is welded to the liquid injection port 19.

  In the manufacturing process of the secondary battery 100, the electrode body 12 is inserted into the case body 14 from the opening of the case body 14, and the lid member 15 and the case body 14 are fixed. For example, first, a lid sub-assembly in which the electrode body 12, the lid member 15, the positive electrode terminal 16, and the negative electrode terminal 17 are connected and integrated is created. Then, the electrode body 12 of the lid sub-assembly is disposed in the case body 14 and the case body 14 and the lid member 15 of the lid sub-assembly are welded. Thereby, the case main body 14 and the lid member 15 are integrated to form the battery case 11. Thereafter, a predetermined amount of electrolytic solution is injected into the battery case 11 from the injection port 19 of the lid member 15. After the injection of the electrolytic solution is completed, a sealing plug 191 is inserted into the injection port 19 and the periphery of the sealing plug 191 is welded. Thereby, the liquid injection port 19 is sealed.

  In the production method of the present invention, the electrode body 12 accommodated in the battery case 11 is dried during the production of the secondary battery and before the injection of the electrolytic solution. Hereinafter, a secondary battery that is in the process of being manufactured and in which the electrode body 12 is accommodated in the battery case 11 and no electrolyte is injected is referred to as an assembly 101. In the assembly 101, neither the plug 191 nor the weld is welded to the liquid injection port 19, and the liquid injection port 19 is open. Further, in the assembly 101, the lid member 15 and the case main body 14 are welded, and there is no opening other than the liquid injection port 19.

  First, a first embodiment embodying the present invention will be described. In the manufacturing method of the first embodiment, the vacuum drying furnace 20 shown in FIG. 2 is used to dry the assembly 101. FIG. 2 shows a state where a plurality of assemblies 101 are arranged in the vacuum drying furnace 20.

  As shown in FIG. 2, the vacuum drying furnace 20 includes a chamber 21, a plate heater 22, a vacuum pump 23, and a nozzle set 24. The chamber 21 has a heat-resistant wall surface and moves up and down to open and close the furnace space. The plate heater 22 is a heat source that heats the inside of the chamber 21, including a flat plate-like electric heating element. The vacuum pump 23 is a pump for reducing the pressure inside the chamber 21.

  The nozzle set 24 is fixed to the mounting hole 25 of the chamber 21 and constitutes a flow path for taking air into the chamber 21 from the outside of the chamber 21. Since the nozzle set 24 is fixed to the chamber 21, when the chamber 21 is opened or closed, it moves together with the chamber 21 in the vertical direction in FIG. FIG. 2 shows a state where the chamber 21 is closed, and the inside of the chamber 21 is sealed. In addition, there is no gap between the nozzle set 24 and the mounting hole 25, and air circulation from this space is suppressed.

  As shown in FIG. 2, the nozzle set 24 includes a plurality of nozzles 26, a filter 27, an on-off valve 28, and a communication passage 29. In the communication passage 29 of the nozzle set 24, a plurality of nozzles 26 are formed on one end side at a predetermined interval, and the other end side is opened to the outside of the chamber 21 through a filter 27 and an on-off valve 28. The filter 27 and the on-off valve 28 are arranged outside the chamber 21 in this order from the side close to the chamber 21. The filter 27 removes foreign substances from the air that flows into the nozzle 26 from the outside of the chamber 21. The on-off valve 28 controls the inflow of air from the outside of the chamber 21 to the communication path 29.

  Each nozzle 26 is disposed inside the chamber 21, and can communicate with the outside of the chamber 21 through a communication path 29 through a filter 27 and an on-off valve 28. That is, if the on-off valve 28 is opened, the air that has passed through the filter 27 from the outside of the chamber 21 can flow into the nozzle 26. On the other hand, if the on-off valve 28 is closed, the air outside the chamber 21 does not flow into the nozzle 26.

  Each nozzle 26 of the nozzle set 24 is inserted into each assembly 101 from the liquid injection port 19 of each assembly 101 as shown in FIG. 3 with the chamber 21 closed. The assembly 101 is put into the chamber 21 so as to be in this arrangement. The outer diameter of the tip 261 that is the side of the nozzle 26 that is inserted into the liquid inlet 19 is smaller than the inner diameter of the liquid inlet 19. Therefore, as shown in FIG. 3, with the nozzle 26 inserted into the liquid injection port 19, there is a gap that allows air to flow between the nozzle 26 and the liquid injection port 19. In FIG. 3, the other assembly 101 and the communication path 29 are omitted.

  In the manufacturing method of this embodiment, as shown in FIG. 2, a plurality of assemblies 101 are put into the vacuum drying furnace 20 as a restraint body 30 that restrains them integrally. As shown in FIG. 4, the restraining body 30 is obtained by integrating a plurality of assemblies 101 with a restraining jig 31. The restraining jig 31 includes a restraining plate 32 at both ends and a plurality of partition plates 33. The restraining jig 31 sandwiches a plurality of assemblies 101 arranged via the partition plate 33 with two restraining plates 32, and restrains the whole as a whole. The partition plate 33 is disposed between the large-area surfaces of the two adjacent assemblies 101, abuts against the assemblies 101 on both sides, and applies a pressing force by the restraint plates 32 to each assembly 101.

  In the chamber 21 of this embodiment, the nozzles 26 are provided in an arrangement that matches the intervals of the assemblies 101 in the restraining body 30. At the time of manufacturing, the position of the liquid injection port 19 of each assembly 101 is aligned with the position corresponding to the position of each nozzle 26, and the restraining body 30 is placed in the vacuum drying furnace 20. Then, by closing the chamber 21, the nozzles 26 are inserted into the respective liquid injection ports 19 as shown in FIG. The number of nozzles 26 is equal to or greater than the number of assemblies 101 included in the restraining body 30, and the nozzles 26 are inserted into all the assemblies 101. Further, if the chamber 21 is moved upward to be opened, each nozzle 26 is positioned away from the liquid injection port 19. That is, the restraint body 30 can be taken in and out of the vacuum drying furnace 20 when the chamber 21 is open.

Next, a manufacturing process in the case of manufacturing the secondary battery 100 using the vacuum drying furnace 20 shown in FIG. 2 will be described. As shown in FIG. 5, the manufacturing process of this embodiment includes the following steps (step 1) to (step 9).
(Process 1) Assembly process (Process 2) Restraint process (Process 3) In-furnace placement process (Process 4) Temperature rising process (Process 5) Depressurization process (Process 6) Re-pressure process (Process 7) Extraction process (Process 8) Injection process (process 9) sealing process

  The assembly step (step 1) is a step of creating the assembly 101. As described above, the assembly 101 is assembled by inserting the electrode body 12 into the case body 14 and welding the lid member 15 to the case body 14.

  The restraining step of (Step 2) is a step of restraining the plurality of assemblies 101 created in (Step 1) with the restraining jig 31 and creating the restraining body 30 as shown in FIG. . For example, the assembly 101 is disposed between the partition plates 33 of the restraining jig 31 and the restraining plates 32 at both ends are gradually tightened to restrain the whole.

  The in-furnace placement step of (Step 3) is a step of placing the restraint body 30 including the plurality of assemblies 101 in the vacuum drying furnace 20 and closing the chamber 21 as shown in FIG. The in-furnace arrangement process of (Process 3) is an example of an arrangement process. In the in-furnace arrangement process, first, the chamber 21 is opened, and the restraining body 30 is arranged on the plate heater 22. In the case of the chamber 21 provided with a plurality of nozzle sets 24 and a plurality of plate heaters 22, a restraining body 30 is disposed on each plate heater 22. After placing the restraint 30, the chamber 21 is lowered and closed. By closing the chamber 21, the tip 261 of each nozzle 26 is inserted into each assembly 101 as shown in FIG. 3.

  The temperature raising step of (Step 4) is a step of raising the temperature in the chamber 21 to a predetermined temperature by the plate heater 22 of the vacuum drying furnace 20. The predetermined temperature is a temperature at which moisture inside the assembly 101 can be appropriately removed, and is, for example, 100 to 105 ° C. Then, when the internal temperature rises to a predetermined temperature, the vacuum drying furnace 20 is controlled so as to maintain the temperature thereafter.

  The decompression step of (Step 5) is a step of decompressing the inside of the vacuum drying furnace 20 that has been heated in (Step 4). The inside of the chamber 21 is depressurized by the vacuum pump 23 until a predetermined pressure is reached. The predetermined pressure is, for example, 5 to 15 kPa (abs) in absolute pressure. When a predetermined pressure is reached, the state is maintained for a predetermined time. At least before the start of the decompression step, the on-off valve 28 is closed and the chamber 21 is sealed.

  In the depressurization step, the air in the chamber 21 flows as shown by the dashed arrows in FIG. By operating the vacuum pump 23, the air in the chamber 21 is drawn into the vacuum pump 23. Further, since there is a gap between the tip 261 of the nozzle 26 and the liquid injection port 19 of the assembly 101, the air inside the assembly 101 is sucked out from this gap. The flow direction of air in the decompression process is a direction from the inside of the assembly 101 to the outside of the assembly 101 through the liquid injection port 19. Further, air remaining in the nozzle 26 and in the communication passage 29 is also sucked out through the liquid injection port 19.

  By the depressurization step, the inside of the chamber 21 is brought into a state of being heated and depressurized. As a result, the interior of the assembly 101 is also heated and depressurized. Since the saturated water vapor pressure can be reduced by reducing the pressure, the inside of each assembly 101 is efficiently dried by raising the temperature and reducing the pressure inside the vacuum drying furnace 20 in which the restraining body 30 is disposed. be able to. (Step 4) and (Step 5) are examples of the drying step. Note that (Step 4) and (Step 5) may be performed in reverse order or simultaneously.

  The decompression step of (Step 6) is a step of increasing the pressure in the vacuum drying furnace 20 to a pressure suitable for opening the chamber 21. In the return pressure process, the pressure is not increased to a pressure exceeding the atmospheric pressure. In the return pressure step, the pressure may be increased to atmospheric pressure, or the pressure may be increased to a pressure lower than atmospheric pressure and capable of opening the chamber 21. (Step 6) is an example of a boosting step.

  Specifically, in the return pressure process, the plate heater 22 is turned off, the vacuum pump 23 is stopped, and the on-off valve 28 is opened. Further, it may be actively cooled. In the return pressure process, the air in the chamber 21 flows as indicated by the dashed arrows in FIG. By opening the on-off valve 28, air flows from the outside of the chamber 21 into the assembly 101 through the nozzle 26. As described above, since the nozzle set 24 includes the filter 27, clean air from which foreign matter has been removed by the filter 27 is supplied to the assembly 101.

  Further, since there is a gap between the nozzle 26 and the liquid injection port 19, air flows out from this gap to a location inside the chamber 21 outside the assembly 101. That is, the flow direction of air in the return pressure process is inflow from the nozzle 26 into the assembly 101 and outflow from the gap between the nozzle 26 and the liquid injection port 19 to the outside. Inflow from a place other than the nozzle 26 and a flow entering the assembly 101 through the chamber 21 are suppressed. Therefore, even if a foreign substance exists in the chamber 21, the possibility that the foreign substance will enter the assembly 101 is small.

  For example, as shown in FIG. 7, a chamber 121 in which the filter 127 is provided in the air intake 125 and the nozzle 26 is not provided is conceivable as a configuration for suppressing the entry of foreign matter from the outside of the vacuum drying furnace 20. However, when the pressure is increased with this configuration, the air taken into the chamber 121 from the air intake 125 via the filter 127 flows into the assembly 101 from the outside of the assembly 101. At this time, as shown in FIG. 7, when the foreign matter P exists in the chamber 121, particularly when the foreign matter P exists on the upstream side of the assembly 101 in the air flow direction, the foreign matter P becomes air. With this flow, there is a possibility of entering the assembly 101. That is, entry of foreign matter from the outside can be suppressed, but it is not preferable because foreign matter existing inside may enter the assembly 101.

  Returning to the explanation of FIG. 5, the take-out step (step 7) is a step of taking out the restraint body 30 from the vacuum drying furnace 20 by opening the chamber 21 after increasing the pressure in the pressure-reducing step. In this embodiment, as described above, since the nozzle set 24 is separated from the assembly 101 by opening the chamber 21, it is easy to take out the restraint 30.

  The liquid injection process of (Process 8) is a process of injecting an electrolytic solution into the assembly 101 from the liquid injection port 19. Further, the sealing step (step 9) is a step of sealing the liquid injection port 19 of the assembly with the sealing plug 191. Thus, the secondary battery 100 is completed.

  As described above in detail, according to the manufacturing method of the first embodiment, in the return pressure step after drying, the air that has passed through the filter 27 is assembled via the nozzle 26 having a smaller diameter than the inner diameter of the liquid injection port 19. It is supplied to the inside of the solid 101. Further, the air flows from the inside of the assembly 101 to the inside of the chamber 21 outside the assembly 101. And the flow of the air which goes to the inside of the assembly 101 from the chamber 21 hardly arises. Therefore, even when foreign matter exists in the chamber 21, entry of foreign matter into the battery case 11 is suppressed.

  Next, a second embodiment of the present invention will be described in detail with reference to the attached drawings. Compared with the first embodiment, this embodiment has a different chamber configuration and a slightly different manufacturing procedure. Specifically, the first embodiment is an example of the vacuum drying furnace 20 using the upper open type chamber 21, whereas the second form is an example of the vacuum drying furnace 20 using the front opening type chamber 21. It is an example. In addition, about the same structure and procedure as 1st form, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 8, the vacuum drying furnace 20 of the second embodiment includes a chamber 51, a plate heater 22, a vacuum pump 23, a nozzle set 54, and a moving member 41 including a motor and an actuator. . The plate heater 22 and the vacuum pump 23 are the same as those in the first embodiment.

  The nozzle set 54 has the same configuration as the nozzle set 24 of the first embodiment. However, while the nozzle set 24 of the first form is fixed to the chamber 21, the nozzle set 54 of the second form is not fixed to the chamber 51. That is, the nozzle set 54 can be moved in the vertical direction in FIG. The nozzle set 54 and the mounting hole 25 of the chamber 51 are in sliding contact with each other, and even if the nozzle set 54 is moved, there is very little air leakage.

  The nozzle 26 of the second embodiment is moved between an upper position and a lower position by the moving member 41 as shown in FIG. 9A shows a state where the nozzle 26 is in the upper position, and FIG. 9B shows a state where the nozzle 26 is in the lower position. In FIG. 9, the on-off valve 28 and the plate heater 22 are omitted. In the upper position of FIG. 9A, the tip end portion 261 of the nozzle 26 is above the assembly 101. In this upper position, even if the restraining body 30 is moved in the horizontal direction, the restraining body 30 can be taken in and out of the chamber 51 without coming into contact with the nozzle 26.

  9B, the tip portion 261 of the nozzle 26 is inserted into the assembly 101 from the liquid injection port 19. That is, the nozzle set 54 of this embodiment is set to the lower position by the moving member 41, so that the arrangement of the nozzles 26 is the same as the closed state of the chamber 21 of the first embodiment. The filter 27 and the on-off valve 28 may be in communication with the nozzle 26 and may move with the nozzle 26 or may not move.

  Next, a manufacturing process in the case of manufacturing the secondary battery 100 using the vacuum drying furnace 20 shown in FIG. 8 will be described. As shown in FIG. 10, the manufacturing process of this embodiment includes (Step 1) to (Step 11). Each step of (Step 1) to (Step 9) is the same step as each step of the first embodiment. The manufacturing process of this embodiment is obtained by adding a lowering process (process 10) for lowering the nozzle 26 and an ascending process (process 11) for raising the nozzle 26 to the manufacturing process of the first embodiment.

  In the in-furnace arrangement step (step 3) of this embodiment, as shown in FIG. 9A, the nozzle 26 is arranged in the upper position, and the restraining body 30 is arranged in the vacuum drying furnace 20. By setting the nozzle 26 in the upper position, the restraining body 30 can be introduced from the front door of the chamber 51. In the in-furnace placement step of this embodiment, the restraint body 30 is simply placed in the vacuum drying furnace 20 and the chamber 51 is closed, and the nozzle 26 remains in the upper position.

  In this embodiment, the nozzle 26 is left in the upper position, the temperature raising step (Step 4) and the pressure reducing step (Step 5) are performed, and the inside of the assembly 101 is dried. In this embodiment, since the nozzle 26 is separated from the liquid injection port 19, the opening area of the assembly 101 is large, and it can be expected to dry in a shorter time than in the first embodiment.

  In this embodiment, after the inside of the assembly 101 is dried, the descending step (step 10) is performed. In (Step 10), the moving member 41 is driven to move the nozzle set 54 downward in FIG. Thereby, each nozzle 26 moves to the lower position shown in FIG. 9B, and the nozzle 26 is inserted into the liquid injection port 19 of the assembly 101. Then, after the movement is completed, the on-off valve 28 is opened, and the return pressure step (step 6) is performed. In the return pressure process, clean air is taken into the assembly 101 as in the first embodiment.

  After the return pressure process is completed, the ascending process (process 11) is performed. In (Step 11), the moving member 41 is driven to move the nozzle set 54 upward in FIG. As a result, each nozzle 26 is in the upper position shown in FIG. Then, in (Step 7), the door of the chamber 51 is opened, and the restraining body 30 is taken out from the vacuum drying furnace 20.

  As described above in detail, also in the manufacturing method of the second embodiment, the pressure recovery process is performed in a state where the nozzle 26 is inserted into the liquid injection port 19 of the assembly 101. Therefore, as in the first embodiment, even when foreign matter is present in the chamber 21, entry of foreign matter into the battery case 11 is suppressed.

  Furthermore, in the second embodiment, since the nozzle 26 is not inserted into the assembly 101 during decompression, the assembly 101 can be easily dried. On the other hand, in the first embodiment, the nozzle 26 is set only by closing the chamber 21, so that the manufacturing process is simple. Further, since the nozzle set 24 is fixed to the chamber 21, sealing between the nozzle set 24 and the mounting hole 25 of the chamber 21 is easy.

  In addition, this form is only a mere illustration and does not limit this invention at all. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, the present invention is applicable not only to lithium ion secondary batteries but also to various secondary battery manufacturing methods as long as it is a manufacturing method in which an electrode body is inserted into a battery case and then dried. For example, not only a wound secondary battery but also a stacked secondary battery may be used. Moreover, not only a square secondary battery but a cylindrical secondary battery may be used.

  Moreover, the restraining method and arrangement | positioning of the some assembly 101 in the restraint body 30 are not restricted to the example of illustration. For example, the assembly 101 may be dried without being constrained. Further, the assembly 101 is not limited to be arranged in one row, and two or more rows may be constrained together. In addition, the configuration in which the restraining body 30 is charged into or taken out from the vacuum drying furnace 20 may be automatically performed by an automatic loading device, or may be semiautomatic or manual. In each embodiment, after the drying process, the assembly 101 is taken out of the chamber, and then the liquid injection process is performed. However, the liquid injection process is continuously performed with the assembly 101 remaining in the chamber. May be executed.

  Further, the member for raising the temperature in the vacuum drying furnace 20 is not limited to the plate heater, and may be anything such as an electric heater or high-temperature air. Moreover, each process of temperature increase and pressure reduction of the vacuum drying furnace 20 may be automatically performed by a program operation, and may be semiautomatic or manual. In each embodiment, the communication passage 29 is communicated with the outside to increase the pressure in the chamber to atmospheric pressure. However, the pressure may be controlled. For example, a pressure control valve may be provided in the communication passage 29. Alternatively, a pressure sensor may be provided, and the chamber may be opened when the inside of the chamber reaches a predetermined pressure lower than atmospheric pressure.

  Further, the nozzle 26 only needs to have an outer diameter of the tip 261 smaller than an inner diameter of the liquid injection port 19, and the diameter may change midway. Further, the nozzle 26 may be inserted into the inner space of the battery case 11 as long as the tip of the tip 261 is inserted to the inner side of the outer surface of the lid member 15. The number of nozzles 26 is preferably the same as the number of assemblies 101 put into the vacuum drying furnace 20, but can be implemented as long as the number is equal to or greater than the number of assemblies 101.

  In each embodiment, the filter 27 and the on-off valve 28 are both arranged outside the chamber and in the order of the filter 27 and the on-off valve 28 from the side close to the chamber. However, the present invention is not limited to this. For example, at least one of the filter 27 and the on-off valve 28 may be disposed inside the chamber. At least the end portion of the communication passage 29 on the side where the nozzle 26 is not formed may be opened to the outside of the chamber 21. Moreover, the filter 27 and the on-off valve 28 may be arranged in reverse order. Further, the filter 27 may not be provided. For example, a device that supplies clean air from the outside may be connected to the communication path 29. However, it is preferable to provide the filter 27 because clean air can be easily supplied.

  Further, in the vacuum drying furnace 20 of the second embodiment including the chamber 51, the position of the step of moving the nozzle 26 is not limited to the example shown in FIG. For example, the lowering process of lowering the nozzle set 54 is not limited to after the assembly 101 is dried, but is after the assembly 101 is placed in the vacuum drying furnace 20 and the chamber 51 is closed, and the pressure-reducing process. Anytime before you start.

DESCRIPTION OF SYMBOLS 11 Battery case 12 Electrode body 19 Injection port 20 Vacuum drying furnace 26 Nozzle 27 Filter 100 Manufacturing apparatus 101 Assembly

Claims (1)

A method of manufacturing a secondary battery having an electrode body including a positive electrode plate and a negative electrode plate, and an electrolyte solution in a battery case,
An arrangement step in which an assembly in which the electrode body is accommodated in the battery case and the electrolyte is not injected is disposed in a vacuum drying furnace;
A drying step of drying the assembly by heating and depressurizing the interior of the vacuum drying furnace in which the assembly is disposed;
A step of boosting the interior of the vacuum drying furnace after drying the assembly;
Including
In the boosting step,
In a state where a nozzle having an outer diameter smaller than the inner diameter of the liquid injection port is inserted into a liquid injection port which is an opening for injecting the electrolytic solution in the assembly, the nozzle is disposed from outside the vacuum drying furnace. A method of manufacturing a secondary battery, wherein air is caused to flow into the assembly through a battery.

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