JP2004247120A - Electrolyte liquid injection method and electrolyte liquid injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection method and an injection device of an electrolyte liquid capable of obtaining a battery with high quality at low cost by reducing liquid loss of the electrolyte liquid, heightening liquid injection accuracy, reducing an impregnating time of the electrolyte liquid into an electrode group, and by preventing the electrolyte liquid from generation of air bubbles. <P>SOLUTION: The pressure of a sealed space of a liquid injection chamber 10, housing a battery case 8 in which an electrode group is stored, is reduced, and the inside of the battery case 8 and a secondary liquid storing chamber 42 having an opening are simultaneously evacuated. A liquid injection port 8a of the battery case 8 is airtightly connected to the opening of the chamber 42 so as to communicate with each other. A fixed amount of electrolyte liquid 2 in a primary liquid storing chamber 12 is transferred to the second chamber 42 through a liquid passage 37 by opening a liquid injection valve 38, and the chamber 42 is kept in an airtight state by closing the liquid injection valve 38. The electrolyte liquid 2 in the chamber 42 is injected in the battery case 8 by reducing an inner cubature of the chamber 42 by the movement of a piston 34 and by directly pressing the electrolyte liquid 2 in the chamber 42 by the piston 34. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention mainly embodies an electrolyte injection method and a method for injecting a predetermined amount of electrolyte into a battery case containing a group of electrodes in a manufacturing process of a sealed battery. The present invention relates to an electrolyte injection device.
[0002]
[Prior art]
2. Description of the Related Art A sealed battery is manufactured through a process in which an electrode group is housed in a battery case, an electrolyte is injected, and an opening or a liquid inlet of the battery case is closed in a sealed state. In the electrolyte injection process, the electrolyte injected into the battery case is formed by stacking positive and negative electrode plates at high density with separators interposed between them, or spirally wound in a stacked state. Since it is difficult to penetrate into the small gap, it takes a long time to impregnate the electrode group with a predetermined amount of the electrolytic solution.
[0003]
Conventionally, in order to quickly impregnate the electrode group with the electrolytic solution, the pressure inside the battery case is reduced by depressurizing the inside of the battery case by a vacuum pump connected in an air-tight manner to the opening of the battery case into which the electrolytic solution has been injected. As a result, air existing in the gaps between the electrode groups is caused to float as bubbles on the liquid surface of the electrolytic solution. However, with this liquid injection means, the penetration of the electrolytic solution into the electrode group can be promoted to some extent, but since the air present in the gaps between the electrode groups becomes fine bubbles, the fine bubbles are formed in the electrode group. Since the liquid does not quickly float on the surface of the electrolytic solution due to adhesion to the surface, the time for injecting the electrolytic solution cannot be sufficiently reduced.
[0004]
In addition, in order to further reduce the electrolyte injection time, in addition to the above-described decompression means, the electrolyte in the battery case is filled with an inert gas or the like while the opening of the battery case filled with the electrolyte is closed. There is also known an apparatus in which an electrolytic solution is forcibly penetrated into an electrode plate group by applying pressure. However, in this device, at the moment when the pressurized state of the battery case is released and the pressure is returned to the atmospheric pressure, the bubbles that have been pressurized in the gaps between the electrode plates and crushed small are greatly expanded. There is a problem that the electrolyte once impregnated in the gap of the battery may jump out of the battery case.
[0005]
Therefore, conventionally, in order to solve the above-mentioned problem, various liquid injection devices described below (hereinafter, referred to as first to fifth conventional techniques) have been proposed. That is, in the liquid injection device of the first prior art, as shown in FIG. 13, the battery case 60 in which the electrode plate group 61 is stored in advance is hermetically closed by the closing cylinder 62, and is connected via the suction portion 63. The electrolytic solution 66 in the temporary storage chamber 65 is injected into the battery case 60 from the injection pipe 67 by driving the piston 64 in a state where the inside of the battery case 60 is depressurized by driving the pressure reducing device (not shown). At the same time, the inside of the battery case 60 is changed from a reduced pressure state to a pressurized state by drive control of a pressure reducer to promote the penetration of the electrolyte 66 into the electrode group 61 (see Patent Document 1). .
[0006]
In the above liquid injection device, the upper end of the liquid injection pipe 67 protrudes above the level of the electrolytic solution 66 in the temporary liquid storage chamber 65, and the electrolyte 66 injected into the temporary liquid storage chamber 65 is injected. In a state where the battery 66 is stored without flowing into the liquid pipe 67, the pressure inside the battery case 60 is reduced, and then the piston 64 pushes up the liquid surface of the electrolyte 66 in the temporary storage chamber 65 and the electrolyte 66 is injected into the liquid pipe 67. The liquid flows into the battery case 60 through the liquid inlet pipe 67 through the inlet of the battery 67.
[0007]
In this liquid injection device, the inside of the battery case 60 closed by the closing cylinder 62 is decompressed by the pressure reducer to exhaust the air in the battery case 60, so that the air existing in the gap between the electrode groups 61 is also exhausted. Thus, the electrolyte solution 66 injected into the battery case 60 is impregnated into the electrode group 61 while promoting penetration into the minute gaps of the electrode group 61. Thereafter, the electrolyte solution 66 is forcibly impregnated into the electrode plate group 61 by increasing the pressure in the battery case 60.
[0008]
In addition, in addition to the configuration of the first prior art, the liquid injection device of the second prior art has a liquid injection nozzle connected to the opening of the battery case, and a bubble is formed above the closed temporary storage chamber. A separation chamber is provided, and air in the temporary storage chamber is exhausted from an exhaust port opened to the bubble separation chamber to reduce the pressure, thereby floating bubbles contained in the electrolyte stored in the temporary storage chamber. Then, the mixture is separated in a bubble separation chamber, and the electrolytic solution is injected into the battery case through a liquid injection nozzle while separating the bubbles (see Patent Document 2). This liquid injection device is intended to prevent bubbles from being injected into the battery case together with the electrolytic solution.
[0009]
Further, as shown in FIG. 14, the third prior art liquid injection apparatus includes a holding table 68 and a liquid injection nozzle 69 which can hold the battery case 60 in a detachable manner and can be moved up and down. An injection chamber 70 formed in a simple closed container, an electrolyte tank 72 that is connected to the injection chamber 70 via a metering pump 71 and stores an electrolyte 66, and an electromagnetic valve provided in the injection chamber 70. A vacuum chamber 73 and an atmosphere opening portion 74 are connected to each other via lines 75 and 76, and a vacuum pump 77 is connected to the liquid injection chamber 70 and the vacuum chamber 73 through electromagnetic valves 78 and 79, respectively. (See Patent Document 3).
[0010]
In the liquid injection device, the liquid injection chamber 70 is closed, and the electromagnetic valve 75 is opened, so that the vacuum chamber 73, whose inside is maintained at a low pressure in advance by driving the vacuum pump 77, communicates with the liquid injection chamber 70. Then, the inside of the battery case 60 housed in the liquid injection chamber 70 is evacuated, and thereafter, the liquid inlet 60 a of the battery case 60 is connected to the liquid injection nozzle 69 by raising the holding table 68, and the liquid injection valve is opened. 80 is opened, a predetermined amount of the electrolyte 66 is injected into the battery case 60 from the injection port 60a by the metering pump 71, and after the injection step, the holding table 68 is lowered to set the injection port 60a to the injection nozzle. Separated from the battery case 69, the battery valve 76 is opened and the pressure in the liquid injection chamber 70 is set to the atmospheric pressure, so that the electrolytic solution 66 in the battery case 60 is pressurized at the atmospheric pressure and forced into the gap between the electrode group 61. To It is aimed to allow-tight.
[0011]
In this liquid injection device, the vacuum chamber 73 whose inside is kept at a low pressure in advance is connected to the liquid injection chamber 70, so that the evacuation time can be shortened and the liquid can be injected efficiently. Further, by connecting the metering pump 71 to the liquid injection nozzle 69 via a pipe line, generation of air bubbles due to air being mixed into the electrolyte 66 in the liquid injection path is prevented.
[0012]
Further, the fourth prior art liquid injection device has a closing portion that hermetically seals the opening of the battery case, and an injection line that is connected to the closing portion at one end and is supplied with the electrolytic solution at the other end. A storage unit provided in the middle of the injection line for storing a predetermined amount of electrolyte to be impregnated into the electrode group in the battery case; a first pressure reducing unit configured to reduce the pressure of the storage unit to a first atmospheric pressure; There is provided an atmosphere opening section that opens the inside of the battery to the atmosphere, and a second pressure reducing section that reduces the pressure inside the battery case to a second pressure lower than the first pressure (see Patent Document 4).
[0013]
In this liquid injection device, defoaming from the electrolytic solution is performed by reducing the pressure in the storage section to the first atmospheric pressure, and the inside of the battery case is reduced to a higher vacuum pressure than the inside of the storage section, whereby the electrolyte solution is applied to the electrode group. The electrolyte is pressurized by promoting permeation and opening the inside of the reservoir to the atmosphere, thereby promoting impregnation of the electrolyte into the electrode plate group.
[0014]
Further, the fifth prior art liquid injection device is configured such that a temporary storage chamber storing a predetermined amount of electrolyte and a battery case accommodating the electrode plate group are separated by a separate storage chamber decompression mechanism and a case decompression mechanism. By separately evacuating and reducing the pressure, the temporary storage chamber is depressurized to a higher pressure than the battery case, and by opening the on-off valve, the pressure difference between the battery case and the temporary storage chamber causes An electrolyte is filled in the battery case (see Patent Document 5).
[0015]
In this liquid injection device, the pressure in the battery case and the temporary storage chamber are separately reduced, so that the battery case is sufficiently depressurized and the air in the battery case is reliably exhausted. After the pressure is reduced without deteriorating the electrolyte, the electrolyte is more quickly and efficiently injected into the battery case.
[0016]
[Patent Document 1]
JP-A-9-99901
[0017]
[Patent Document 2]
JP-A-11-26331
[0018]
[Patent Document 3]
JP-A-2000-182599
[0019]
[Patent Document 4]
JP-A-11-73942
[0020]
[Patent Document 5]
JP 2002-274504 A
[0021]
[Problems to be solved by the invention]
However, each of the above-described conventional liquid injection devices has a problem that must be solved. That is, in the liquid injection device of the first prior art in FIG. 13, when the inside of the battery case 60 is evacuated by driving the pressure reducer prior to the injection of the electrolyte 66, the electrolyte 66 in the temporary storage chamber 65 is discharged. Since the space above the liquid level is in communication with the battery case 60 through the liquid injection pipe 67, the inside of the battery case 60 cannot be raised to a degree of vacuum equal to or lower than the vapor pressure of the electrolyte solution 66, and also temporarily. The electrolyte 66 in the storage chamber 65 cannot be reliably injected into the battery case 60. In addition, when the electrolytic solution 66 is pressurized by the piston 64, the gap between the battery case 60 and the injection port of the injection tube 67 is separated, so that the pressure applied by the piston 64 is directly transmitted to the electrolytic solution 66. Therefore, the impregnation of the electrode plate group with the electrolyte solution 66 cannot be sufficiently promoted, and the injection time is long, and the electrolyte solution 66 in the battery case 60 may spill outside. Since the electrolyte 66 is one of the more expensive materials among the battery materials, the economic loss is increased. As a result, in this liquid injection device, the accuracy of injection of the electrolytic solution 66 into the battery case 60 is reduced, so that the battery capacity is reduced.
[0022]
In addition, in the above liquid injection device, if bubbles exist in the electrolyte solution 66 stored in the temporary storage chamber 65, the bubbles cannot be removed in the subsequent liquid injection process. Since the battery is injected into the battery case 60 and the required electrical characteristics cannot be obtained when the battery is used, the quality of the battery deteriorates. Further, when the electrolytic solution 66 in the temporary storage chamber 65 is injected into the battery case 60 through the injection pipe 67 by the piston 64, the pressing force of the piston 64 is directly applied to the electrolytic solution 66 in the battery case 60. Cannot work. This is because the battery case 60 and the liquid injection port of the liquid injection pipe 67 are separated from each other. As a result, in this liquid injection device, the electrolyte 66 cannot be quickly penetrated into the electrode plate group 61, and the injection time may not be sufficiently reduced.
[0023]
In the liquid injection device of the second prior art, the bubbles of the electrolytic solution stored in the temporary liquid storage chamber can be removed by floating them and separating them in the bubble separation chamber. As in the prior art, when the inside of the battery case is evacuated by driving the pressure reducer prior to the injection of the electrolyte, the space above the liquid surface of the electrolyte in the temporary storage chamber is filled with the battery case through the injection tube. Because the battery case cannot be raised to a degree of vacuum lower than the vapor pressure of the electrolyte, the electrolyte cannot be quickly penetrated into the electrode group, and the injection time is reduced. In addition to being unable to shorten sufficiently, the injection accuracy may be low depending on the condition setting.
[0024]
Further, in the third prior art liquid injection device, the measuring pump 71 is directly connected to the battery case 60 in a sealed state without a temporary liquid storage section by a pipe, and the space between the measuring pump 71 and the battery case 60 is filled with the electrolytic solution. Since the liquid is filled with 66, it is preferable that one measuring pump 71 is used to inject the liquid with high accuracy.
[0025]
Further, in this liquid injection device, the time for evacuating the battery case 60 is shortened. However, in the case of a high-capacity battery, the electrolytic solution 66 in the battery case 60 is pressurized more than the evacuation time and the electrode plate is pressed. It takes time to penetrate the group 61. On the other hand, in this liquid injection device, after the electrolyte 66 is injected into the battery case 60, the injection port 60a of the battery case 60 is separated from the injection nozzle 69, and the inside of the injection chamber 70 is set to the atmospheric pressure. It is only necessary to pressurize the electrolyte 66 in the battery case 60 at this atmospheric pressure. With such a pressurizing means, it takes time for the electrolyte 66 to penetrate into the electrode plate group 61, and the productivity is remarkably reduced particularly when multiple electrodes are used.
[0026]
Further, in the liquid injection device of the fourth prior art, the electrolytic solution injected into the reservoir under the atmospheric pressure is evacuated to remove bubbles in the liquid. In addition, it is difficult to completely remove bubbles in the liquid. Also, when the electrolyte is made to permeate the electrode group, only the differential pressure between the vacuum pressure in the battery case and the atmospheric pressure that has been reduced in advance is relied on, so it takes a long time to impregnate the electrode group with the electrolyte. In addition to the fact that the electrolyte is open to the atmospheric pressure, air bubbles are entrained in the electrolyte during the process of infiltration into the electrode plate group, and the impregnation time of the electrolyte takes a long time. In addition, a problem that the electrolyte overflows outside the battery case is likely to occur.
[0027]
In addition, in this liquid injection device, in order to allow the electrolyte to quickly penetrate into the gap between the electrode groups, a means for releasing the battery case to atmospheric pressure and simultaneously pressurizing the inside of the battery case with a piston is provided. Bubbles easily mix in the electrolyte.
[0028]
Furthermore, in the liquid injection device of the fifth prior art, the pressure in the battery case and the temporary storage chamber are separately reduced, so that bubbles in the electrolyte are removed and bubbles are mixed into the electrolyte during the injection process. However, the electrolyte is injected into the battery case only by relying on the pressure difference between the battery case and the temporary storage chamber, and a means for forcibly injecting the electrolyte into the battery case is provided. Since it is not necessary, it takes a long time to impregnate the electrode group with the electrolytic solution, which not only cannot improve the productivity, but also highly viscous electrolytic solution easily adheres and remains on the inner wall surface of the liquid supply path. And air bubbles are easily generated.
[0029]
In addition, in the above liquid injection device, in order to separately reduce the pressure in the battery case and the temporary liquid storage chamber, a filling cylinder provided with a temporary liquid storage chamber inside the liquid storage chamber pressure reducing mechanism is provided. An exhaust cylinder having a gas exhaust path for the case depressurizing mechanism is arranged, the exhaust cylinder is arranged so as to be able to move up and down in the axial direction inside the filling cylinder, and an open / close valve is provided at a lower end of the exhaust cylinder. , The on-off valve is opened, and the exhaust cylinder is lowered to close the on-off valve, resulting in high cost.
[0030]
As described above, in each conventional injection device, it takes time to infiltrate the electrolyte into the electrode plate group, and the productivity is low, bubbles are easily mixed in the electrolyte, or bubbles in the electrolyte are It is difficult to completely remove the battery, the quality of the battery deteriorates, the cost of equipment increases, or the cost increases due to the large amount of liquid loss. However, there remains a problem that the accuracy of liquid injection is reduced due to the occurrence and stable battery performance cannot be obtained.
[0031]
In view of the above, the present invention has been made in view of the above-mentioned conventional problems, and while reducing the liquid loss of the electrolytic solution to achieve high injection accuracy, the impregnation time of the electrolytic solution into the electrode plate group is reduced. An electrolyte injection method and an electrolyte injection device that can achieve high quality by preventing bubbles from being mixed into the electrolyte while achieving high quality batteries, and can also reduce costs. It is intended to provide.
[0032]
[Means for Solving the Problems]
In order to achieve the above object, an electrolyte injection method according to the present invention includes an electrolyte supply step of supplying a fixed amount of electrolyte from an electrolyte tank into a primary storage chamber, and a battery case containing an electrode plate group. By being housed in a closed space inside the liquid injection chamber and reducing the pressure in the closed space, the inside of the battery case is communicated with the primary liquid storage chamber through a liquid passage provided with a liquid injection valve in the middle. A battery case exhausting step of simultaneously evacuating the interior of the secondary storage chamber opened toward the closed space, and a liquid inlet or opening of the battery case whose interior is evacuated to the secondary storage chamber. A battery case connection step of air-tightly communicating with the opening of the liquid chamber, and opening the injection valve to send the electrolytic solution in the primary storage chamber to the secondary storage chamber via the liquid passage. Supplying electrolyte solution, and supplying the primary solution in the primary storage chamber. After the solution has been supplied to the secondary storage chamber, the injection valve is closed to keep the secondary storage chamber in a sealed state, and the internal volume of the secondary storage chamber is operated by operating a piston. And injecting the electrolytic solution in the secondary storage chamber into the battery case while directly pressurizing the electrolytic solution on the piston surface.
[0033]
In this electrolyte injection method, the piston is operated to reduce the internal volume of the secondary storage chamber while keeping the internal volume of the secondary storage chamber airtight, so that the electrolyte is directly injected by the piston without any intervening pressurized gas or the like. While pressurizing, the electrolyte is forcibly injected into the pre-evacuated battery case through a liquid inlet or opening of the battery case connected to the pre-evacuated secondary storage chamber. The time required for impregnation of the electrode group can be greatly reduced, and the electrolytic solution can be applied to any part of the liquid injection passage from the primary storage chamber through the liquid passage and the secondary storage chamber to the inside of the battery case. Since the solution does not come into contact with the atmosphere and the pressure of the piston acts directly on the electrolyte, no gas is mixed into the electrolyte during the injection process. The gas in the liquid becomes bubbles There is no possibility that things like flooding the solution liquid occurs, also be pouring accuracy is greatly improved liquid loss is reduced, obtaining a stable high-quality battery electrical properties.
[0034]
In the liquid injection step in the above invention, it is preferable to apply a pressure for preventing swelling equal to the pressure applied to the electrolytic solution by the piston to the outer surface of the battery case. According to this means, in spite of forcibly injecting the electrolytic solution into the battery case by applying the pressing force of the piston directly to the electrolytic solution, particularly when the pressing force is applied to the inside, the electrolytic solution moves outward. Even when the electrolytic solution is injected into a square battery case that is likely to swell and deform, the long side plate portion of the square battery case can be prevented from swelling and deforming outward. Therefore, even when the injection pressure of the electrolytic solution is promoted by setting the pressurizing pressure by the piston high, it is possible to prevent the battery case from bulging outward.
[0035]
As means for applying the pressure for preventing swelling, a rectangular battery case having a rectangular or elliptical cross-sectional shape may be provided by holding a battery case having an inner peripheral surface capable of forming a small gap with the outer peripheral surface of the battery case. The battery case is housed in the closed space of the liquid injection chamber while being inserted into the shape container, and a pressing force for preventing the battery case from expanding can be applied to the inner peripheral surface of the shape holding container.
[0036]
This makes it possible to reliably prevent outward swelling of the rectangular battery case, while having a very simple configuration, and to release the pressure applied by the piston to allow the battery case to be filled with the secondary storage chamber. When the battery case is separated from the battery case, the battery case returns to the original shape, so that the battery case in which the electrolyte has been injected can be easily taken out of the shape-retaining container.
[0037]
As another means for applying the pressure for preventing swelling, an inert gas is supplied into the closed space of the liquid injection chamber, and the pressure in the closed space becomes substantially equal to the pressure applied to the electrolytic solution by the piston. The supply of the inert gas may be controlled as described above. This means can also effectively prevent outward bulging deformation of the battery case.
[0038]
In the above invention, it is preferable that a preliminary defoaming step of removing bubbles in the electrolytic solution by evacuating the inside of the electrolytic solution tank prior to the electrolytic solution supplying step is preferable. Thereby, the electrolytic solution in the electrolytic solution tank can be supplied to the primary storage chamber after removing most of the bubbles contained therein.
[0039]
Further, in the above invention, while comprising a defoaming step of removing air bubbles in the electrolyte by evacuating the primary storage chamber to which a fixed amount of the electrolyte has been supplied through the electrolyte supply step, in the electrolyte transfer step, Open the injection valve and transfer the electrolyte in the primary storage chamber to the secondary storage chamber by the differential pressure between the vacuum pressure of the liquid level of the electrolyte in the primary storage chamber and the vacuum pressure in the secondary storage chamber. It is preferred to supply.
[0040]
According to this means, after removing bubbles remaining in the electrolyte in the primary storage chamber, the difference in pressure between the vacuum pressure of the electrolyte in the primary storage chamber and the vacuum pressure in the secondary storage chamber is obtained. Since the electrolyte in the primary storage chamber is supplied to the secondary storage chamber, the electrolyte does not come into contact with the atmosphere, so there is no risk of bubbles entering the electrolyte and the amount of evaporation of the electrolyte is significantly reduced. Since this can be reduced, the liquid loss is further reduced, and the injection accuracy is further improved.
[0041]
After the piston is operated for a predetermined stroke and stopped in the liquid injection step in the above invention, the liquid injection valve is opened to supply an inert gas from the primary liquid storage chamber to the secondary liquid storage chamber via the liquid passage, A second injection step of injecting the electrolyte remaining in the secondary storage chamber into the battery case by the flow of the inert gas, and a time when the liquid level of the electrolyte becomes lower than the injection port of the battery case; After closing the liquid injection valve, the liquid inlet of the battery case is separated from the secondary storage chamber, and the pressure of the inert gas supplied into the liquid injection chamber causes the electrolyte in the battery case to be discharged. Preferably, a third liquid injection step of applying pressure is provided.
[0042]
Thereby, the pressure of the piston is directly applied to the electrolyte in the secondary storage chamber, and almost all of the predetermined amount of the electrolyte is forcibly injected into the battery case. The remaining electrolyte is pressurized by pressurized gas supplied through the primary storage chamber, the liquid passage, and the piston, and the electrolyte in the battery case is further pressurized by pressurized gas supplied to the closed space of the injection chamber. Since the pressure is applied, it is possible to reliably inject a predetermined amount of the electrolyte solution without any residual solution, so that the injection accuracy is further improved, and the electrolyte solution can be very smoothly penetrated into the electrode group in the battery case, The injection time can be further reduced.
[0043]
Instead of the third injection step in the above invention, even after the liquid level of the electrolytic solution becomes lower than the injection port of the battery case by the second injection step, the state of the second injection step is changed. Providing a third injection step of pressurizing the electrolyte in the battery case by the pressure of the inert gas supplied into the battery case through the primary storage chamber, the liquid passage, and the secondary storage chamber while holding the battery; You can also.
[0044]
Also in this case, a predetermined amount of the electrolyte can be very efficiently penetrated into the minute gaps between the electrode plates in the battery case, and can be filled in the battery case in a short time. Further shortening and further improvement of injection accuracy can be achieved.
[0045]
On the other hand, the electrolyte injection device according to the present invention, the primary storage container is a sealed container inside the primary storage chamber, and the fixed amount of the electrolyte supplied from the electrolyte tank by driving the metering pump, A liquid injection nozzle for injecting the liquid into the primary storage chamber, a first vacuum pump and a first pressurized gas supply unit each connected to the primary storage chamber by a pipe, a piston, and an upper end provided in the primary storage chamber. A liquid passage having a lower part penetrated by a piston, a liquid injection valve interposed in the middle of the liquid path, and a piston mechanism which is lifted and lowered integrally; A liquid chamber, a battery case support base provided inside the liquid injection chamber, and raised and lowered while holding a battery case into which an electrolyte is to be injected, and penetrating the upper end of the liquid injection chamber in an airtight state. The supported cylinder and the The piston is slid in an airtight state on a surface thereof, and the upper end surface of the battery case is hermetically contacted with a lower end surface of the cylinder by raising the battery case support base. A secondary storage chamber formed in a closed space by closing the liquid passage with a liquid valve.
[0046]
In this electrolyte injection device, the primary storage chamber can be evacuated by the first vacuum pump, and the first pressurized gas supply unit supplies the secondary storage chamber through the primary storage chamber and the liquid passage. A pressurized gas can be supplied to the electrode to act on the electrolyte, and by opening and closing the injection valve, the connection between the primary storage chamber and the secondary storage chamber can be connected and disconnected via the liquid passage, and the piston mechanism By this, the electrolyte in the secondary storage chamber can be directly pressurized, and the cylinder, piston, and battery case can form a secondary storage chamber in a closed space. It can be embodied faithfully and the effect of the injection method can be reliably obtained. In the case of a rectangular battery case, the upper end surface of the battery case forming the secondary storage chamber is a peripheral edge of a hole of a liquid inlet in a sealing plate that seals an upper end opening of the battery case, and has a cylindrical shape. In the case of a battery case, it is the entire open end surface of the battery case, and in any case, the lower end surface of the cylinder is brought into tight contact with the lower end surface of the cylinder via a sealing member such as a sealing packing or a ring packing. .
[0047]
In the above invention, the battery case support is provided inside the liquid injection chamber and moves up and down while holding the battery case into which the electrolyte is to be injected, and the pipes are respectively connected to the closed space inside the liquid injection chamber. It is preferable to include a second vacuum pump and a second pressurized gas supply unit.
[0048]
According to this configuration, the liquid port or opening of the battery case can be connected to or separated from the opening of the secondary storage chamber in an airtight manner by the raising and lowering operation of the battery case support. The vacuum pump and the second pressurized gas supply unit can perform evacuation and pressurization by the pressurized gas separately from the primary storage chamber with respect to the injection chamber.
[0049]
In the above invention, the piston Cylindrical It is preferable that a piston seal is fixed to at least a lower end portion of the outer peripheral surface so as to slide in an airtight manner with the inner peripheral surface of the cylinder. As a result, even if a highly viscous electrolytic solution adheres to the inner surface of the cylinder, the adhered electrolytic solution can be wiped off with the piston seal and injected into the battery case, thereby further improving the accuracy of liquid injection. Can be achieved.
[0050]
In the above invention, it is preferable that the injection nozzle, which is pipe-connected to the electrolyte tank via the metering pump, is provided with a movable type that is detachably connected to the primary storage chamber. . According to this configuration, when the devices are arranged in multiple units, it is not necessary to connect the metering pump and the battery case in a one-to-one correspondence, so that a simple and inexpensive configuration can be achieved, and equipment costs are included. Manufacturing costs can be significantly reduced.
[0051]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view showing an electrolyte injection device embodying an electrolyte injection method according to one embodiment of the present invention. This embodiment exemplifies a case in which the electrolytic solution 2 is injected into a rectangular battery case 8 having a rectangular or oval cross-sectional shape. When injecting the rectangular battery case 8, the electrolyte 2 is injected from a relatively small inlet 8 a provided in a sealing plate (not shown) for closing the opening of the battery case 8. Unlike the cylindrical battery case in which the entire upper end is open, it is difficult to inject the electrolyte 2 efficiently. Further, when pressure is applied to the inside of the rectangular battery case 8, the long side plate portion 8b having a larger area than the short side plate portion 8c is easily deformed so as to bulge outward.
[0052]
The electrolytic solution injecting device is roughly classified into an electrolytic solution tank 1 for storing an electrolytic solution 2, a predetermined amount of electrolytic solution supplied from the electrolytic solution tank 1 via a metering pump 3 and an injection nozzle 4. A primary storage container 7 for temporarily storing the electrolyte solution 2 in an internal primary storage chamber 12, a cylinder 9 for storing the electrolyte solution 2 supplied from the primary storage container 7 and injecting the electrolyte solution 2 into a battery case 8, A piston mechanism 33 for injecting the electrolyte 2 into the battery case 8 while pressurizing the electrolyte 2 therein, and an injection chamber 10 which is a closed container for accommodating the battery case 8 into which the electrolyte 2 is to be injected. ing.
[0053]
The electrolytic solution 2 stored in the electrolytic solution tank 1 is an electrolytic solution for a lithium secondary battery in this embodiment, and is a mixed solvent of EC (ethylene carbonate) and DMC (dimethyl carbonate). _i PF ₆ Was dissolved at 10 wt%. The vapor pressure of this electrolytic solution 2 is 2.4 kPa (18 mmHg, 9 ° C.). In the metering pump 3, the electrolyte tank 1 is connected to the suction-side head by a pipe, and the injection nozzle 4 is connected to the discharge-side head by a pipe. A vacuum pump 15 for defoaming is connected to the electrolytic solution tank 1 via a solenoid valve 5 and connected to the atmosphere opening via another solenoid valve 16. .
[0054]
The above-mentioned electrolytic solution tank 1, metering pump 3 and injection nozzle 4 are fixedly installed at a predetermined injection station. The apparatus main body excluding these components is sequentially transported and stopped at the injection station. You. The liquid injection nozzle 4 is movable so as to be detachably connected to the primary liquid storage chamber 12 inside the primary liquid storage container 7 when the apparatus main body is stopped and the lid 6 of the primary liquid storage container 7 is removed. It is an expression. The lid 6 that opens and closes the primary storage chamber 12 hermetically seals the primary storage chamber 12 via a sealing packing 24.
[0055]
A first vacuum pump 14 has a first solenoid valve 13 interposed in a connection pipe 19 connected to the primary storage container 7 by communicating with an exhaust / pressurization port at the upper end of the primary storage chamber 12. The first pressurized gas supply unit 18 is connected through a pipe via a second solenoid valve 17 while being connected through a pipe. The first pressurized gas supply unit 18 supplies a pressurized gas at a pressure of 1 MPa or less. As the pressurized gas, an inert gas such as nitrogen, argon, neon, or helium can be used. ₂ Is used. The exhaust / pressurization port at the upper end of the primary liquid storage chamber 12 is formed to have a small diameter of about φ1 to 2 mm.
[0056]
On the other hand, the liquid injection chamber 10 is separated into a chamber upper body 10A and a chamber lower body 10B. The chamber upper body 10A is fixed to the apparatus main body, and the chamber lower body 10B is provided so as to be able to move up and down so as to come into contact with and separate from the chamber upper body 10A. The interior of the injection chamber 10 is formed in a closed container by pressing the raised chamber lower body 10B against the chamber upper body 10A with a ring-shaped seal member 21 interposed therebetween.
[0057]
Inside the lower chamber body 10B, a shape-retaining container 25 into which the battery case 8 can be inserted and removed, a battery case support 22 for supporting the shape-retainer 25, and the battery case support 22 are raised and lowered. A battery case elevating mechanism 23 is provided. The shape-retaining container 25 has a shape having an inner peripheral surface capable of forming a small gap entirely with the outer peripheral surface of the rectangular battery case 8 having a rectangular or oval cross-sectional shape. Although the battery case 8 can be easily inserted and removed, when the battery case 8 is to be expanded by receiving a pressing force described later, it functions to apply a pressing force to the battery case 8 to prevent the expansion. Although not shown, the battery case elevating mechanism 23 is connected to the compressor through a pipe having a valve interposed therebetween, and the piston 23a supporting the battery case support base 22 moves up and down at a predetermined stroke by switching control of the valve. Is done.
[0058]
The cylinder 9 is attached to the chamber upper body 10A so as to penetrate the upper wall of the chamber upper body in an airtight state. The inner lower end of the cylinder 9 has a funnel-shaped reduced diameter, and the lower end opening is formed in a liquid feed port 9 a having a diameter corresponding to a relatively small liquid inlet 8 a in the rectangular battery case 8. Further, a sealing gasket 27 is fixed to the lower end surface of the cylinder 9 so as to surround the liquid feed port 9a. The material of the sealing gasket 27 is EPDM having excellent elasticity and adhesion.
[0059]
Further, a second vacuum pump 29 is connected to a connection pipe 28 that is attached to a side wall of the chamber upper body 10A through a third electromagnetic valve 30 and a second vacuum pump 29. The pressurized gas supply unit 31 is connected through a pipe with a fourth solenoid valve 35 interposed. The second pressurized gas supply unit 31 supplies a pressurized gas at a pressure of 1 MPa or less. As the pressurized gas, an inert gas such as nitrogen, argon, neon, or helium can be used. ₂ Is used.
[0060]
Between the primary storage container 7 and the cylinder 9, there is provided a piston mechanism 33 which is raised and lowered by a piston lifting mechanism 32 including a piston lifting cylinder. The piston mechanism 33 slides on the inner peripheral surface of the cylinder 9 and moves up and down, a connecting body 36 connected to the piston 34, and an upper end which is penetrated by the connecting body 36 and the piston 34, respectively. An opening is provided with a liquid passage 37 communicating with the primary liquid storage chamber 12, and a small injection valve 38 provided at an intermediate portion of the liquid passage 37 in the connecting body 36. The liquid passage 37 has a small diameter of about 1 to 2 mm. The upper end of the connecting body 36 is connected to the piston lifting / lowering mechanism 32 via an auxiliary connecting body 43 shown in FIGS. 7 to 11 described later, and the liquid passage 37 is connected to the primary through the auxiliary connecting body 43. It is communicated with the liquid storage chamber 12.
[0061]
On the outer peripheral surface of the piston 34, two circumferential annular grooves 11 are formed at upper and lower ends of the piston 34, and a piston seal 41 made of an O-ring is fitted and fixed in the annular grooves 11. Have been. When the piston 34 is moved up and down, the piston seal 41 slides in an airtight manner on the inner peripheral surface of the cylinder 9 to keep the inside of the cylinder 9 always closed. Further, the lower end surface of the piston 34 is formed in a funnel shape corresponding to the cylinder 9.
[0062]
The battery case 8 is removably supported on the battery case support 22 in a state where the electrode plate group (not shown) is previously housed therein, and then inserted and held in the shape-retaining container 25 from above. You. When the battery case lifting / lowering mechanism 23 is raised to the upper limit position, the upper end surface of the battery case 8 is held against the sealing gasket 27 as shown in FIG. It is pressed with a force to compress it by about 0.5 mm. As a result, the cylinder 9 is airtightly connected to the battery case 8 with the lower end liquid supply port 9a sealed with the sealing gasket 27, and the upper part is closed with the piston 34 and the piston seal 41, and the cylinder 9 is sealed inside. A secondary storage chamber 42, which is a space, is formed. However, the secondary storage chamber 42 communicates with the inside of the battery case 8 via the sealing gasket 27, and communicates with the primary storage chamber 12 through the liquid passage 37 when the injection valve 38 is opened. .
[0063]
The two connecting pipes 19 and 28 are branched and connected to an atmosphere opening pipe provided with solenoid valves 39 and 40, respectively, so that the solenoid valves 39 and 40 can be moved prior to the lowering operation of the lower chamber body 10B. , 40 are opened, the closed spaces of the primary storage chamber 12 and the injection chamber 10 are each opened to the atmosphere, and the above-described pressurized gas is released to the outside.
[0064]
Next, the injection operation by the above-mentioned electrolyte injection device will be described with reference to FIGS. In these figures, in order to facilitate understanding, the metering pump 3, the vacuum pumps 14, 15, 29 and the pressurized gas supply units 18, 31 are indicated by a solid line in the driving state and in a non-driving state. Each is schematically illustrated by a broken line.
[0065]
First, in the battery case mounting step of FIG. 2, the apparatus main body is conveyed in a state where the lower chamber body 10B of the liquid injection chamber 10 is separated from the upper chamber body 10A and lowered to the lower battery case mounting position, and the injection is performed. When the positioning at the liquid station is stopped, the rectangular battery case 8 in which the electrode plate group is stored in advance is inserted into and removed from the shape retaining container 25 in the lower chamber body 10B. At this time, the defoaming vacuum pump 15 is driven as shown by a solid line, whereby bubbles in the electrolytic solution 2 in the electrolytic solution tank 1 are removed in advance.
[0066]
Subsequently, as shown in FIG. 3, the lower chamber body 10 </ b> B in which the battery case 8 is mounted in the shape-retaining container 25 on the battery case support base 22 is raised, so that the chamber lower body 10 </ b> B The liquid injection chamber 10 is formed in tight contact with the upper body 10A, together with the chamber upper body 10A. The interior of the injection chamber 10 becomes a closed space by closing the injection valve 38. The inside of the battery case 8 communicates with the closed space of the liquid injection chamber 10 through the liquid injection port 8a.
[0067]
When the liquid injection chamber 10 is configured as described above, the second vacuum pump 29 is driven as shown by a solid line after the third solenoid valve 30 is opened, and thereby the liquid injection chamber 10 is formed. The pressure in the closed space 10 and the secondary storage chamber 42 which is open downward is reduced to 0.3 to 1.3 kPa. At this time, the closed space of the liquid injection chamber 10 and the secondary liquid storage chamber 42 are shut off from the primary liquid storage chamber 12 by the liquid injection valve 38 in the closed state. The pressure is reduced reliably and quickly.
[0068]
Since the inside of the battery case 8 communicates with the closed space of the injection chamber 10 through the injection port 8a, the pressure of the closed space of the injection chamber 10 is reduced to 0.3 to 1.3 kPa as described above. With this, the inside of the battery case 8 is also evacuated to substantially the same pressure. According to the measurement results of these examples, when the second vacuum pump 29 was driven for 30 seconds, the pressure inside the battery case 8 could be reduced to a degree of vacuum of 0.3 to 1.3 kPa. Thereby, the air existing in the small gaps between the electrode groups in the battery case 8 is smoothly exhausted to the outside as the inside is reduced to a relatively high degree of vacuum.
[0069]
On the other hand, in the primary storage container 7, the lid 6 is removed and the upper part of the primary storage chamber 12 is opened, and the injection nozzle 4 is detachably connected to the primary storage chamber 12. Subsequently, when the metering pump 3 is driven as shown by the solid line, a fixed amount (2.0 g ± 0.1 in this embodiment) of the electrolyte 2 is stored in the primary storage chamber 12. 1 through the metering pump 3 and the injection nozzle 4. Here, it is preferable that the electrolytic solution 2 is evacuated in the electrolytic solution tank 1 and defoamed in advance.
[0070]
In this electrolytic solution injection device, each device main body is sequentially conveyed to an injection station provided with a single metering pump 3 and an injection nozzle 4, and the primary storage of the device body stopped at the injection station. The injection nozzles 4 are sequentially connected to the chamber 12 to supply the electrolytic solution 2. Therefore, when the apparatus main bodies are arranged in multiple units, the number of metering pumps 3 and liquid injection nozzles 4 to be installed can be greatly reduced.
[0071]
When a predetermined amount of the electrolytic solution 2 is supplied into the primary storage chamber 12, as shown in FIG. 4, after the first solenoid valve 13 is opened in advance, the first vacuum pump 14 is shown by a solid line. And the pressure in the primary storage chamber 12 is reduced to a reduced pressure atmosphere of 13.3 kPa. As a result, the bubbles contained in the electrolyte 2 float on the liquid surface and are then exhausted. The results of actual measurement when the defoaming step of the electrolytic solution 2 was performed showed that when the first vacuum pump 14 was driven for 30 seconds, the degree of pressure reduction of the electrolytic solution 2 was 13.3 kPa. Since the primary storage chamber 12 is isolated from the closed space of the injection chamber 10 by the injection valve 38 in the closed state, the second storage chamber 12 is different from the second vacuum pump 29 for reducing the pressure of the injection chamber 10. The one vacuum pump 14 can surely reduce the pressure to a set pressure different from the pressure in the closed space of the liquid injection chamber 10. That is, in the electrolyte injection device, the primary storage chamber 12 and the closed space of the injection chamber 10 can be separately evacuated and reliably reduced to different set pressures by an extremely simple configuration.
[0072]
In the defoaming step of the electrolytic solution 2, the primary storage chamber 12 is set to have an internal volume substantially equal to the amount of the electrolyte solution 2 injected into the battery case 8, and Since the exhaust / pressurization port to which the connection 19 is connected is set to a small diameter of φ1 to 2 mm, the evaporation of the electrolyte 2 when the electrolyte 2 is evacuated by driving the first vacuum pump 14 is suppressed. As a result, the liquid loss can be significantly reduced, so that highly accurate liquid injection can be performed. Also, in this defoaming step, unlike the conventional means for evacuating the electrolyte injected into the battery case, the electrolyte 2 in the primary storage chamber 12 is evacuated. Bubbles in the electrolytic solution 2 can be almost certainly removed.
[0073]
On the other hand, in the liquid injection chamber 10, after the inside of the battery case 8 is evacuated to a predetermined degree of vacuum by driving the second vacuum pump 29, the battery case elevating mechanism 23 discharges the piston 23a by a predetermined stroke. Since the battery case 8 is driven to raise the battery case support 22 to the upper limit position, the upper end surface of the battery case 8 held in the shape-retaining container 25 on the battery case support 22 is 0.5 mm with respect to the sealing gasket 27. It is pressed to a state where it is compressed to a degree, and is hermetically sealed by the sealing gasket 27 and is in close contact with the lower end surface of the cylinder 9. Communicated. Thereby, a secondary liquid storage chamber 42 sealed by the liquid injection valve 38, the battery case 8, the piston 34, and the piston seal 41 in a closed state is formed inside the cylinder 9. The inside of the battery case 8 communicates with 42.
[0074]
Next, as shown in FIG. 5, the injection valve 38 is opened, and the primary storage chamber 12 and the secondary storage chamber 42 are communicated via the liquid passage 37. Therefore, the electrolytic solution 2 in the primary storage chamber 12 has a pressure difference between the pressure on the liquid surface of the electrolytic solution 2 in the primary storage chamber 12 and the pressure in the secondary storage chamber 42 (13. (3 kPa-0.3 to 1.3 kPa), and is supplied into the secondary storage chamber 42 and further into the battery case 8 which is maintained at the same pressure as the secondary storage chamber 42 and the liquid supply port 9a and the injection port. It is injected through the liquid port 8a. The supply of the electrolytic solution 2 from the primary storage chamber 12 to the secondary storage chamber 42 is performed using the pressure difference between the two pressures as described above. 2 does not come into contact with the atmosphere, so that no bubbles are mixed into the electrolytic solution 2 and the secondary storage chamber 42 is maintained at a relatively high vacuum of 0.3 to 1.3 kPa. Since the supply of the liquid 2 is completed in a short time and the primary storage chamber 12 is set to a relatively low vacuum of 13.3 kPa, there is no possibility that the electrolyte 2 will be boiled.
[0075]
When the supply of the electrolytic solution 2 in the primary storage chamber 12 into the secondary storage chamber 42 is completed, the process proceeds to a first injection step. That is, as shown in FIG. 6, when the first liquid storage chamber 12 and the liquid passage 37 are evacuated by driving the first vacuum pump 14, the injection valve 38 is closed again, and the secondary liquid storage chamber is closed. 42 and the primary storage chamber 12 are shut off. Thereafter, as shown in FIG. 7, the piston elevating mechanism 32 is driven, and the piston mechanism 33 starts the lowering operation. The piston 34 of the piston mechanism 33 directly pressurizes the electrolytic solution 2 in the secondary storage chamber 42 at a pressure of 0.75 MPa with the descending operation.
[0076]
Thereby, most of the electrolytic solution 2 in the secondary storage chamber 42 is forcibly injected into the battery case 8 and then effectively promoted to quickly penetrate into the minute gaps of the electrode plate group. Is done. Further, since the piston 34 performs a descending operation while maintaining the airtight state with respect to the cylinder 9 by the piston seal 41, the electrolytic solution 2 is exposed to the atmosphere despite being directly pressurized by the piston 34. Since there is no air bubble, no air bubbles are mixed. Moreover, even if the highly viscous electrolytic solution 2 adheres to the inner peripheral surface of the cylinder 9, the adhered electrolytic solution 2 is reliably wiped off by the piston seal 41, so that the liquid is injected with high injection accuracy. can do.
[0077]
If the electrolytic solution 2 starts to be forcibly injected into the battery case 8 due to the direct pressurization of the piston 34, the rectangular battery case 8 directly receives the pressing force due to the downward movement of the piston 34. As a result, the internal pressure is increased by the electrolyte solution 2 that is injected very quickly, and the long-side plate portion 8b of the battery case 8 that is particularly easily deformed tends to swell outward. However, since the rectangular battery case 8 is inserted into the shape-retaining container 25 having an inner peripheral surface slightly larger than the outer shape of the battery case 8, the bulging of the long-side plate portion 8 b causes the inner surface of the shape-retaining container 25 to bulge. This prevents the battery case 8 from bulging and deforming outward. At this time, by opening the fourth solenoid valve 35 and driving the second pressurized gas supply unit 31, the battery case is activated by the pressure of the inert gas supplied from the second pressurized gas supply unit 31. It is preferable to further surely prevent outward bulging deformation of 8.
[0078]
As shown in FIG. 8, when the piston 34 is lowered to the lower limit position, the outer surface of the lower taper of the piston 34 except for the outer peripheral surface of the cylinder and the inner surface of the lower taper of the cylinder 9 come into close contact with each other, and the secondary liquid is stored. The chamber 42 has disappeared, and the electrolytic solution 2 remains at the lower end of the liquid passage 37. In a state where the piston 34 is stopped at the lower limit position, the second liquid injection step is started. That is, after the injection valve 38 is opened and the second solenoid valve 17 is opened, the first pressurized gas supply unit 18 is driven as shown by a solid line. N as the pressurized gas supplied from the first pressurized gas supply unit 18 ₂ Passes through the primary storage chamber 12 and the liquid passage 37 and directly pressurizes the electrolyte 2 remaining in the liquid passage 37 at a pressure of 0.75 MPa, so that the electrolyte 2 is injected into the battery case 8. Infusion is effectively promoted. Further, the piston 34 is formed using PTFE as a forming material, and the electrolytic solution 2 does not easily adhere thereto. Thereby, the liquid loss of the electrolytic solution 2 can be further suppressed.
[0079]
Then, as shown in FIG. 9, if the liquid level of the electrolytic solution 2 drops below the liquid inlet 8 a on the upper end surface of the battery case 8 due to pressurization by the pressurized gas, the second liquid injection step ends. Subsequently, the process proceeds to a third liquid injection step shown in FIG. That is, the injection valve 38 is closed to shut off the connection between the secondary storage chamber 42 and the primary storage chamber 12, the drive of the first pressurized gas supply unit 18 is stopped, and the second pressurization is performed. The driving of the gas supply unit 31 is continued, and the sealed space of the liquid injection chamber 10 is maintained at a pressure of 1 MPa. The state in which the liquid level of the electrolytic solution 2 has dropped below the injection port 8a of the battery case 8 is, for example, a case where the timing is started from the start of the injection and the elapsed time is monitored, and the predetermined time from the start of the injection It is detected when the time has elapsed. The predetermined time is determined in advance by experiment.
[0080]
At the same time, the battery case lifting / lowering mechanism 23 is driven to suck the piston 23a by a predetermined stroke to lower the battery case support 22 to the lower limit position, so that the battery case 8 held on the battery case support 22 is Move away from the cylinder 9. As a result, the electrolytic solution 2 injected into the battery case 8 is pressurized by the pressure of 1 MPa in the closed space of the liquid injection chamber 10 and efficiently penetrates into the small gaps of the electrode group.
[0081]
As described above, in each of the first injection steps, a relatively large pressing force of 0.75 MPa due to the lowering operation of the piston 34 is directly applied to the electrolytic solution 2, and in the second injection step, the first injection step is performed. A relatively large pressing force of 0.75 MPa by the pressurized gas from the pressurized gas supply unit 18 is directly applied to the electrolytic solution 2, and in the third injection step, the second pressurized gas supply unit 31 Since a relatively large pressing force of 1 MPa by the pressurized gas from the battery is directly applied to the electrolytic solution 2, a predetermined amount of the electrolytic solution 2 is extremely efficiently applied to the minute gaps between the electrode plates in the battery case 8. The battery case 8 in a short time.
[0082]
When the injection is completed as described above, the solenoid valves 39 and 40 in FIG. 1 are opened, and the pressurized gas in the primary storage chamber 12 and the injection chamber 10 is discharged to the outside. Finally, as shown in FIG. 11, the lower chamber body 10 </ b> B of the liquid injection chamber 10 is lowered to a predetermined position, and the battery case 8 in which the injection of the electrolytic solution 2 has been completed is taken out of the shape retaining container 25. At this time, since the direct pressing force on the electrolytic solution 2 by the piston 34 has already been released, the long side plate portion 8b that has once bulged out of the battery case 8 has returned to the original state, and the battery case 8 Can be easily taken out.
[0083]
In the above-described electrolytic solution injection device, while the simple configuration in which the rectangular battery case 8 is simply inserted into the shape-retaining container 25 is employed, the piston 34 is used to forcibly inject the electrolytic solution 2 into the battery case 8. The swelling deformation of the long side plate portion 8b can be reliably prevented. However, instead of the means for preventing the swelling deformation of the battery case 8 by the shape retaining container 25, the battery case 8 is placed on the battery case support base 22. And pressurized gas is supplied from the second pressurized gas supply unit 31 into the closed space of the liquid injection chamber 10 during the first liquid injection step in which the piston 34 is operated. Even when the supply of the pressurized gas is controlled so that the pressure is substantially equal to the pressure applied to the electrolytic solution 2 by the piston 34, the swelling deformation of the rectangular battery case 8 can be prevented. Further, as means for preventing the battery case 8 from bulging and deforming, the above-mentioned means holding container 25 is provided, and a pressurized gas is supplied from the second pressurized gas supply unit 31 into the closed space of the liquid injection chamber 10. By doing so, the swelling deformation of the battery case 8 can be more reliably prevented.
[0084]
In the third injection step, the pressing force of the pressurized gas from the second pressurized gas supply unit 31 is directly applied to the electrolytic solution 2. However, in the third injection step, Alternatively, after the second liquid injection step is completed, the second liquid injection step may be continued as it is, and this may be set as a third liquid injection step. That is, in the third liquid injection step, the pressurized gas supplied from the first pressurized gas supply unit 18 is directly added to the electrolytic solution 2 in the battery case 8 through the primary storage chamber 12 and the liquid passage 37. Press. Also in this case, the predetermined amount of the electrolyte solution 2 can be extremely efficiently penetrated into the minute gaps between the electrode plates in the battery case 8 and can be filled in the battery case 8 in a short time.
[0085]
FIG. 12 shows an electrolyte injection device according to another embodiment of the present invention. In FIG. 12, the same or equivalent components as those in FIG. Only the configuration different from FIG. 1 will be described. In this electrolytic solution injection device, a case where liquid is injected into a cylindrical battery case 44 is illustrated, and the battery case 44 is not inserted into the shape retaining container 25 as in the embodiment, It is held on a battery case support 22. The entire upper end of the cylindrical battery case 44 is open. Corresponding to the cylindrical battery case 44, a portion of the piston 49 extending from the lower end of the liquid passage 37 to the liquid feed port 49a extends downward. An escape hole 49b having an open conical cross section is formed. A ring packing 50 is attached to a lower end surface of the cylinder 9.
[0086]
The basic pouring process in this electrolytic solution pouring apparatus is the same as that of the above-described embodiment, except that the battery case supporting table 22 is raised by the operation of the battery case elevating mechanism in the battery case connecting step. In this case, the upper end surface of the cylindrical battery case 44 is air-tightly attached to the ring packing 50, and the upper end opening of the cylindrical battery case 44 communicates with the secondary storage chamber 42. Thereby, the opening of the entire upper end of the cylindrical battery case 44 is connected to the secondary storage chamber 42 in an airtight state without any trouble.
[0087]
Also, during the first liquid injection step in which the piston 49 descends, pressurized gas is supplied from the second pressurized gas supply unit 31 into the closed space of the liquid injection chamber 10, and the pressure in the closed space is reduced by the piston 49. The supply of the pressurized gas is controlled so as to be substantially equal to the pressure applied to the electrolytic solution 2 by the pressure. As a result, the outer surface of the cylindrical battery case 44 is pressurized by the pressure of the pressurized gas in the closed space of the injection chamber 10, and swells outward against the pressing force of the electrolytic solution 2 inside. Deformation is prevented.
[0088]
【The invention's effect】
As described above, according to the electrolytic solution injection method of the present invention, by reducing the internal volume of the secondary storage chamber while maintaining the internal volume in an airtight state by operating the piston, the piston can be operated without pressurized gas or the like. While the electrolyte is directly pressurized in the battery case, the electrolyte is evacuated in advance through a liquid inlet or an opening of the battery case which is connected in a gas-tight manner to a pre-evacuated secondary storage chamber. Forcibly injects the electrolyte solution into the battery case through the primary storage chamber through the liquid passage and the secondary storage chamber, while greatly shortening the time of impregnation of the electrolyte into the electrode group. Since the electrolyte does not come into contact with the atmosphere in any part of the injection passage and the pressure of the piston acts directly on the electrolyte, bubbles are mixed into the electrolyte during the injection process. There is no fear that the amount of electrolyte Since the gas can be reduced to a lower level and gas does not mix into the electrolyte, there is no danger that the gas in the electrolyte becomes bubbles when the pressure is released and overflows the electrolyte. , The injection accuracy is remarkably improved, and a high-quality battery with stable electric characteristics can be obtained.
[0089]
Further, according to the electrolytic solution injection device of the present invention, the primary vacuum chamber can be evacuated by the first vacuum pump, and the first pressurized gas supply unit allows the primary fluid chamber to communicate with the primary fluid chamber and the liquid passage. Pressurized gas can be supplied to the secondary storage chamber to act on it, and the connection and cutoff between the primary storage chamber and the secondary storage chamber via the liquid passage can be performed by opening and closing the injection valve. The electrolyte solution in the secondary storage chamber can be pressurized by the piston mechanism, and the secondary storage chamber in a closed space can be configured by the cylinder, the piston, and the battery case. And the effect of the liquid injection method can be reliably obtained.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing an electrolyte injection device embodying an electrolyte injection method according to an embodiment of the present invention.
FIG. 2 is a schematic vertical sectional view of the electrolyte injection device in the battery case mounting step.
FIG. 3 is a schematic vertical cross-sectional view in a battery case exhausting step of the electrolytic solution injecting apparatus.
FIG. 4 is a schematic longitudinal sectional view of the electrolytic solution injection device in the electrolytic solution defoaming and battery case connecting steps.
FIG. 5 is a schematic vertical cross-sectional view of an electrolytic solution injecting apparatus in the electrolytic solution transferring step.
FIG. 6 is a schematic longitudinal sectional view of the electrolyte injection device in the same state in a preparation state for starting a first injection step.
FIG. 7 is a schematic longitudinal sectional view of the electrolyte injection device in the same state in a first injection step.
FIG. 8 is a diagram illustrating an opening of a second injection step of the electrolyte injection device according to the first embodiment. Beginning FIG. 3 is a schematic longitudinal sectional view in a state.
FIG. 9 is a schematic vertical cross-sectional view of the above-described electrolytic solution injection device in a state where a second injection step is completed.
FIG. 10 is a schematic longitudinal sectional view in a third injection step of the electrolyte injection device of the above.
FIG. 11 is a schematic longitudinal sectional view of the electrolyte injection device in the battery case mounting step.
FIG. 12 is a schematic longitudinal sectional view showing an electrolyte injection device according to another embodiment of the present invention.
FIG. 13 is a sectional view showing a conventional liquid injection device.
FIG. 14 is a schematic configuration diagram showing another conventional liquid injection device.
[Explanation of symbols]
1 Electrolyte tank
2 Electrolyte
3 Metering pump
4 Injection nozzle
7 Primary storage container
8 Battery case
8a Filling port
9 cylinders
10 Injection chamber
12 Primary storage chamber
14 First vacuum pump
18 First pressurized gas supply unit
22 Battery case support
25 Shape-keeping containers
29 Second vacuum pump
31 Second pressurized gas supply unit
33 piston mechanism
34 piston
37 liquid passage
38 Injection valve
41 Piston seal
42 Secondary storage chamber
44 Battery case
49 piston

Claims (12)

An electrolyte supply step of supplying a fixed amount of electrolyte from the electrolyte tank into the primary storage chamber,
The battery case accommodating the electrode plate group is housed in a sealed space inside the injection chamber and the inside of the sealed space is decompressed, so that the inside of the battery case and a liquid passage provided with an injection valve in the middle are formed. A battery case exhausting step of simultaneously evacuating the interior of the secondary storage chamber, which communicates with the primary storage chamber through, and opens toward the sealed space,
A battery case connection step of connecting the liquid inlet or opening of the battery case whose interior has been evacuated to the opening of the secondary storage chamber in an airtight manner
By opening the injection valve, an electrolyte transfer step of feeding the electrolyte in the primary storage chamber to the secondary storage chamber through the liquid passage,
After the supply of the electrolytic solution in the primary storage chamber to the secondary storage chamber is completed, the injection valve is closed to hold the secondary storage chamber in a sealed state, and the secondary operation is performed by operating a piston. A liquid injection step of injecting the electrolyte in the secondary storage chamber into the battery case while directly pressurizing the electrolyte in the secondary storage chamber by reducing the internal volume of the storage chamber. Characteristic electrolyte injection method. 2. The electrolyte injection method according to claim 1, wherein in the injection step, a pressure for preventing swelling equivalent to a pressure applied to the electrolyte by the piston is applied to the outer surface of the battery case. With the rectangular battery case having a rectangular or elliptical cross-sectional shape inserted into a shape-retaining container having an inner peripheral surface capable of forming a small gap between the outer peripheral surface of the battery case and the injection chamber, The electrolytic solution injection method according to claim 2, wherein a pressurizing force that is accommodated in a closed space and that prevents swelling of the battery case is applied to an inner peripheral surface of the shape-retaining container. An inert gas is supplied into the closed space of the liquid injection chamber, and the supply of the inert gas is controlled so that the pressure in the closed space is substantially equal to the pressure applied to the electrolytic solution by the piston. Item 4. The method for injecting an electrolytic solution according to Item 2 or 3. 5. The method for injecting an electrolytic solution according to claim 1, further comprising a preliminary defoaming step for removing bubbles in the electrolytic solution by evacuating the electrolytic solution tank prior to the electrolytic solution supplying step. . In addition to having a defoaming step of removing air bubbles in the electrolyte by evacuating the primary storage chamber to which a fixed amount of the electrolyte has been supplied through the electrolyte supply step, in the electrolyte transfer step, the injection valve is opened. The electrolyte in the primary storage chamber is supplied to the secondary storage chamber by a differential pressure between the vacuum pressure of the liquid level of the electrolyte in the primary storage chamber and the vacuum pressure in the secondary storage chamber. Item 6. The method for injecting an electrolytic solution according to any one of Items 1 to 5. In the liquid injection step, after the piston operates and stops for a predetermined stroke, the liquid injection valve is opened to supply an inert gas from the primary liquid storage chamber to the secondary liquid storage chamber through the liquid passage, and A second injection step of injecting the electrolyte remaining in the storage chamber into the battery case by flowing the inert gas;
When the liquid level of the electrolytic solution becomes lower than the liquid inlet of the battery case, after closing the liquid injection valve, the liquid inlet of the battery case is separated from the secondary storage chamber, and the inside of the liquid inlet chamber is 7. The method according to claim 1, further comprising: a third injection step of pressurizing the electrolyte in the battery case with a pressure of an inert gas supplied to the battery case. In place of the third liquid injection step according to claim 7, even after the liquid level of the electrolytic solution becomes lower than the liquid inlet of the battery case by the second liquid injection step, the second liquid injection step is performed in the second liquid injection step. A third injection step of pressurizing the electrolyte in the battery case by the pressure of the inert gas supplied into the battery case through the primary storage chamber, the liquid passage, and the secondary storage chamber while maintaining the state. The method for injecting an electrolytic solution according to claim 7 provided. A primary storage container in a closed container with an internal primary storage chamber,
A liquid injection nozzle for injecting a fixed amount of electrolyte supplied from the electrolyte tank by driving a metering pump into the primary storage chamber,
A first vacuum pump and a first pressurized gas supply unit each connected to the primary storage chamber by a pipe,
A piston mechanism which is integrally provided with a piston, a liquid passage having an upper end communicating with the primary storage chamber and a lower part penetrated by the piston, and a liquid injection valve interposed in the middle of the liquid passage, and being moved up and down. When,
An injection chamber that is an airtight container that can be opened and closed,
A cylinder which is supported in an airtight manner at the upper end of the liquid injection chamber, the piston which is slid in an airtight manner on an inner peripheral surface of the cylinder, and a lower portion of the cylinder when the battery case support is raised. A secondary storage formed in a closed space by being enclosed by a liquid inlet of an upper end surface of the battery case which is in air-tight contact with an end surface and closed by the liquid passage by the liquid injection valve in a closed state. An electrolyte injection device, comprising: a liquid chamber. A battery case support base provided inside the liquid injection chamber for raising and lowering while holding the battery case into which the electrolyte is to be injected, and a second vacuum pipe connected to a closed space inside the liquid injection chamber, respectively. The electrolytic solution injection device according to claim 9, further comprising a pump and a second pressurized gas supply unit. The electrolytic solution injection device according to claim 10, wherein a piston seal is fixed to at least a lower end portion of the outer peripheral surface of the piston in an airtight manner with respect to an inner peripheral surface of the cylinder. The electrolyte injection liquid according to claim 9 or 10, wherein the injection nozzle connected to the electrolyte tank via a metering pump is detachably connected to the primary storage chamber. apparatus.

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