JPH1055808A - Method for filling case with electrolyte through small-diameter filling hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent a spout of an electrolyte from a case via a small- diameter filling hole, when the case is forcibly supplied with a large volume of the electrolyte in a short time and then a filling nozzle is removed. SOLUTION: This method for filling a case with an electrolyte from a small-diameter hole involves the processes where the open part of a case 1 having an electrode group 4 inserted is closed with a sealing plate 15 having a small-diameter filling hole 2, the outer side of the small-diameter filling hole 2 is sealed with an airtight chamber 14, and a nozzle 9 in the airtight chamber 14 is connected to the small-diameter hole 2 for forcibly feeding the case 1 with a pressurized electrode 3 from the nozzle 9. In this case, the pressing force of the airtight chamber 14 is kept almost equal to the internal pressure of the case 1 with the forcibly fed electrolyte 3, or higher than the internal pressure of the case 1. In this state, the nozzle 9 is detached from the small-diameter filling hole 2 and the pressing force of the airtight chamber 14 is used to prevent a spout of the forcibly supplied electrolyte 3 from the small-diameter filling hole 2. Thereafter, a condition is maintained for preventing a spout of the electrolyte 3 from the small-diameter filling hole 2 and, then, the airtight chamber 14 is released to the atmospheric pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for closing an opening of a case with a sealing plate and filling the case with an electrolyte through a small-diameter filling hole of the sealing plate.

[0002]

2. Description of the Related Art A battery or a capacitor is manufactured by filling a case containing an electrode group with an electrolytic solution and then sealing the opening of the case with a sealing plate. According to this method, the case can be filled with the electrolytic solution relatively quickly. However, this method cannot safely fill all batteries and the like with the electrolytic solution. For example, in a lithium ion battery or the like, an opening of a case filled with an electrolyte cannot be hermetically sealed by welding. This is because, when the sealing plate is welded to the opening, the electrolyte ignites and the state becomes extremely dangerous.

In a battery or the like having this structure, after an electrode group is placed in a case, an opening of the case is closed with a sealing plate, an electrolytic solution is filled through a small-diameter filling hole provided in the sealing plate, and finally, a small-diameter filling hole is formed. It is manufactured by sealing. In this manufacturing method, it is necessary to fill the electrolytic solution from a small-diameter filling hole provided in the sealing plate. The method of filling the case with the electrolyte from the small-diameter filling hole has a disadvantage that the filling time is considerably long.

[0004] Various methods have been developed to shorten the filling time from the small-diameter filling hole of the sealing plate. For example, the following gazette describes a method of filling an electrolytic solution as an environment in which the inside of the case is decompressed to easily fill the electrolytic solution. JP-B-5-78139 JP-A-63-48778 JP-A-63-91952 JP-A-4-345755

In the filling method described in these publications, as shown in FIGS. 1 and 2, the case 1 is filled with the electrolytic solution 3 from the small-diameter filling hole 2 in the following steps. As shown in FIG. 1, a filling chamber 5 is connected to the small-diameter filling hole 2. By operating the vacuum pump 6, the pressure in the filling chamber 5 is reduced,
Reduce the pressure inside the case. At this time, the electrolyte 3
Do not supply. Thereafter, as shown in FIG. 2, the electrolyte 3 is supplied to the filling chamber 5. The electrolytic solution 3 in the filling chamber 5 passes through the small-diameter filling hole 2 and is filled in the case. Since the pressure in the case is reduced, the air accumulated in the gaps of the electrode group 4 and the like is discharged. For this reason, the electrolytic solution 3 filled in the case 1
Compared to a method in which the inside of the case is not decompressed, the gas quickly penetrates into the gap between the electrode groups 4.

[0006]

As described above, the method of injecting the electrolyte after reducing the pressure in the case has a feature that the electrolyte can be injected into the gap between the electrode groups relatively quickly.
However, even with this method, it is not possible to inject the electrolytic solution within a sufficiently satisfactory time. Particularly, in a lithium ion battery or the like in which the density of the electrode group is very high, there is a disadvantage that it takes time to impregnate the minute gaps of the electrode group with the electrolytic solution. Further, for a battery or the like filled with an electrolyte, it is extremely important how the tact time can be reduced. When the tact time is long, there is a disadvantage that the number of manufactured units per unit time is reduced and the manufacturing cost is increased. For this reason, shortening the filling time of the electrolyte is extremely important in the production of batteries and the like.

[0007] In order to further shorten the filling time, a method has been developed in which the electrolyte is pressed into the case after the pressure has been reduced. This manufacturing method is described, for example, in the following publication. JP-A-2-172158 JP-B7-1118307

[0008] As shown in FIG. 3, the method described in the publication discloses a case in which a case 1 is disposed in a hermetic chamber 7, the air in the hermetic chamber 7 is exhausted, and then the hopper is connected to an opening of the case 1. The electrolytic solution 3 is supplied to the airtight chamber 8, and then the airtight chamber 7 is pressurized to forcibly penetrate the electrolytic solution 3 into the gap between the electrode groups 4 in the case. In this method, the electrolytic solution 3 is pressurized and the electrode group 4
Therefore, there is a feature that the electrolytic solution 3 can be quickly penetrated. However, this method has a disadvantage that it is difficult to quickly inject the electrolyte into the case from a very small small-diameter filling hole.

In the filling method described in the above publication, the electrolytic solution can be quickly filled into the case from the small-diameter filling hole. In this method, as shown in FIG. 4, after the inside of the case is depressurized by a vacuum pump 6, the nozzle 9 is inserted into the case and the electrolyte 3 is press-fitted. In this method, since the electrolytic solution 3 is injected into the case 1 through the nozzle 9, the flow rate of the electrolytic solution 3 to be filled in the case 1 can be increased. However, in this method, when a large amount of the electrolytic solution 3 is injected into the case 1 at a time, when the nozzle 9 is removed from the small-diameter filling hole 2, there is a problem that the electrolytic solution 3 blows out from the small-diameter filling hole 2. In order to prevent this adverse effect, a predetermined amount of the electrolytic solution is press-fitted little by little over a plurality of times. For this reason, there is a disadvantage that the injection time of the electrolyte cannot be reduced so much.

The present invention has been developed for the purpose of overcoming these conventional disadvantages. An important object of the present invention is that a large amount of electrolyte can be press-fitted into the case in a short time, and when the injection nozzle is removed from the small-diameter filling hole,
An object of the present invention is to provide a method of filling an electrolytic solution into a case from a small-diameter filling hole that can effectively prevent an electrolytic solution in the case from spouting from the small-diameter filling hole.

[0011]

According to the method of filling an electrolytic solution into a case from a small-diameter filling hole according to the present invention, the electrolytic solution is filled as described below to achieve the above-mentioned object. According to the filling method of the present invention, the opening of the case 1 into which the electrode group 4 having the laminated structure is inserted is closed by the sealing plate 15 having the small-diameter filling hole 2 formed therein. This is an improved method in which a fixed amount of the electrolytic solution 3 is filled, the gap between the electrode groups 4 is impregnated with the electrolytic solution 3, and then the small-diameter filling hole 2 of the case 1 is closed.

According to the filling method of the present invention, the outside of the small-diameter filling hole 2 opened in the sealing plate 15 is sealed by an airtight chamber 14, and the nozzle 9 provided in the airtight chamber 14 is connected to the small-diameter filling hole 2. Then, the pressurized electrolyte 3 is injected into the case 1 from the nozzle 9. Thereafter, the pressure of the airtight chamber 14 outside the small-diameter filling hole 2 is substantially equal to or higher than the internal pressure of the case 1 into which the electrolytic solution 3 has been pressed, and the nozzle 9 is moved from the small-diameter filling hole 2. Remove and press the airtight chamber 14
The electrolytic solution 3 press-fitted into the case 1 is prevented from blowing out from the small-diameter filling hole 2. In this state, the electrolytic solution 3 is
After that, the airtight chamber 14 is opened to the atmospheric pressure after the electrolyte 3 is not injected from the small-diameter filling hole 2.

Further, in the method of filling an electrolytic solution according to the present invention, preferably, after the airtight chamber 14 is depressurized and the inside of the case 1 is depressurized, the nozzle 9 is connected to the small-diameter filling hole 2 and 3. Press-fit. This method has the advantage that the electrolyte 3 can be injected in the shortest time since the pressure inside the case 1 is reduced and then the electrolyte 3 is injected under pressure.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. However, the following examples illustrate a filling method for embodying the technical idea of the present invention, and the present invention does not limit the filling method to the following method.

Further, in this specification, in order to make it easy to understand the claims, the numbers corresponding to the members shown in the embodiments will be referred to as “claims” and “ In the column of “means”. However, the members described in the claims are not limited to the members of the embodiments.

In the method of filling an electrolyte shown in FIGS. 5 to 8, a case of a lithium ion secondary battery is filled with the electrolyte as described below. However, in the method of filling the electrolytic solution of the present invention, the electrolytic solution can be injected into a case other than the lithium ion secondary battery in the same manner.

(1) As shown in FIG. 5, the case 1 closed by the sealing plate 15 is inserted into the fitting recess 10a of the base 10 and is mounted in a fixed position. In the case 1, after the stacked electrode group 4 is inserted via the separator, the opening is closed by a sealing plate 15 having the small-diameter filling hole 2 opened. Case 1
Is made of metal and is formed into a square tube, a cylinder, and an elliptic tube.
The bottom of the case 1 is closed, and the upper end is open. The sealing plate 15 is closely attached to the opening at the upper end of the case 1 without any gap. The sealing plate 15 is hermetically connected to the opening by a method such as welding, bonding, or caulking such as laser welding. The sealing plate 15 has a small-diameter filling hole 2 into which the electrolytic solution 3 is injected. If the small-diameter filling hole 2 is made small, it can be easily sealed after the electrolyte 3 is injected. When it is large, it is convenient for the injection of the electrolyte 3. The size of the small-diameter filling hole 2 is set to, for example, about 1 to 3 mmφ in consideration of sealing later and the injection efficiency of the electrolytic solution 3.

(2) As shown in FIG. 6, the closing cylinder 11 is lowered to the outside of the base 10 to seal the outside of the small-diameter filling hole 2 with the airtight chamber 14. The airtight chamber 14 is formed by the base 10 and the closing cylinder 20. The O-ring 13 provided on the outside of the base 10 includes the base 10 and the closed cylinder 2.
The gap with 0 is hermetically sealed.

(3) Thereafter, air is exhausted from the inside of the closed cylinder 20, and the pressure in the airtight chamber 14 is reduced. Airtight room 1
In order to depressurize 4, the closing cylinder 20 is opened and closed
4 and connected to a vacuum source 25. When the airtight chamber 14 is connected to the vacuum source 25 by opening the on-off valve 24, the airtight chamber 14
The air is exhausted from and the pressure is reduced.

(4) Thereafter, as shown in FIG. 7, the closing cylinder 11 for fixing the nozzle 9 is lowered, and the tip of the nozzle 9 is airtightly connected to the small-diameter filling hole 2 via the packing 18. With the nozzle 9 connected to the small-diameter filling hole 2,
The injection piston 12 is lowered, and the electrolyte 3 is pressed into the case 1 from the nozzle 9. The injection pressure of the electrolytic solution 3 can be adjusted by the pressing force for lowering the injection piston 12. The injection piston 12 presses the electrolyte 3 into the case 1 from the small-diameter filling hole 2 at an injection pressure of, for example, 1 to 8 kg / cm ² .

When the electrolyte 3 is pressed into the case 1 from the nozzle 9, the press pressure, which is the pressure of the airtight chamber 14, is applied to the nozzle 9.
Is set almost equal to the injection pressure. When the press pressure of the airtight chamber 14 is substantially equal to the injection pressure of the electrolyte 3, it is possible to effectively prevent the electrolyte 3 from leaking from the gap between the nozzle 9 and the small-diameter filling hole 2. However, when the tip of the nozzle 9 is airtightly connected to the small-diameter filling hole 2 via the packing 18, it is not always necessary to set the press pressure of the airtight chamber 14 to the injection pressure of the nozzle 9. From the gap between the nozzle 9 and the small-diameter filling hole 2, the electrolyte 3
Is not leaked.

(5) Before the electrolytic solution 3 is injected into the case 1 and the nozzle 9 is separated from the small-diameter filling hole 2, the press pressure of the airtight chamber 14 is set substantially equal to the internal pressure of the case 1 into which the electrolytic solution 3 has been injected. Or higher than the internal pressure of the case 1. The airtight chamber 14 is connected to a pressurized air source 26 via an on-off valve 24, and the on-off valve 24 can be opened to pressurize the air. However, at this time, the on-off valve 24 connected to the vacuum source 25 is closed. In a state where the airtight chamber 14 is pressurized, as shown in FIG.
The nozzle 9 is separated from the small-diameter filling hole 2. At this time, the airtight room 1
The press pressure of 4 is such that the electrolyte 3 in the case 1
Prevent injection from the. This is because the internal pressure of the case 1 does not become higher than the external pressure. The internal pressure of the case 1 gradually decreases as the electrolyte 3 penetrates into the gap between the electrode groups 4. In this state, the electrolytic solution 3 is made to permeate the gap between the electrode groups 4. As the electrolyte 3 penetrates into the gaps between the electrode groups 4, the electrolyte 3 becomes less likely to be ejected from the small-diameter filling hole 2, so that the press pressure of the airtight chamber 14 can be gradually reduced.

(6) Even if the case 1 is opened to the atmospheric pressure, when the electrolyte 3 permeates until the electrolyte 3 is not injected from the small-diameter filling hole 2, the closed cylinder 11 is raised and the airtight chamber 14 is raised. Is opened, and the case 1 into which the electrolyte 3 has been injected is taken out from the base 10.

(7) Then, the small-diameter filling hole 2 of the sealing plate 15
Are hermetically closed.

In the above method, the pressure in the case 1 is reduced,
The electrolytic solution 3 is press-fitted from the nozzle 9. In this method, since the case 1 is depressurized and the electrolytic solution 3 is press-fitted, the electrolytic solution 3 can permeate into the gaps of the electrode group 4 more quickly. However, the electrolytic solution can also be injected from the nozzle without depressurizing the case.

Hereinafter, an apparatus used in the method for filling an electrolytic solution of the present invention will be described in detail. The apparatus shown in FIG. 5 includes a base 10, a closing cylinder 11, a nozzle 9, and an injection piston 12. One or several or several tens of devices as shown in the figure are arranged as a line, and each device fills the case 1 with the electrolytic solution 3 in parallel to increase the processing capacity.

The base 10 has a fitting recess 10a into which the case 1 is fitted and which is mounted in a fixed position. The fitting recess 10a holds the case 1 so as not to be displaced. Therefore, the fitting recess 10 a has an inner shape substantially equal to the outer shape of the case 1. The case 1 is inserted into the fitting recess 10a with almost no gap, and is held so as not to move in the horizontal direction. Since the case 1 is formed in the shape of a square tube, a cylinder, or an elliptic tube, the fitting recess 10a is also formed in the same shape. The case 1 is vertically inserted into and removed from the fitting recess 10 a of the base 10.

The base 10 has a sliding surface 10b on which the inner surface of the closing cylinder 11 slides. The sliding surface 10b is provided with a groove around the O-ring 13 therein. O-ring 1
Numeral 3 tightly adheres to the inner surface of the sliding closing cylinder 11 to form an airtight chamber 14.

The case 1 set in the fitting recess 10a of the base 10 has the laminated electrode group 4 inserted therein via a separator. Further, in the case 1, the sealing plate 15 is laser-welded to the opening to hermetically close the opening. The sealing plate 15 holds the case 1 before the electrolyte 3 is injected.
Therefore, a small-diameter filling hole 2 for injecting the electrolytic solution 3 is opened.

The closing cylinder 11 has a cylindrical shape that slides hermetically along the sliding surface 10b of the base 10. As shown in FIGS. 6 and 8, the closing cylinder 11 is provided with a position where the nozzle 9 is separated from the small-diameter filling hole 2 and a state where the nozzle 9 is connected to the small-diameter filling hole 2 as shown in FIG. It is high enough to seal. Furthermore, the closing cylinder 11
Are connected to a vertical guide 16 so as to be moved up and down. Although not shown, the closing cylinder 11 is moved up and down via a hydraulic piston, a cam, a lever, and the like.

Further, the closing cylinder 11 shown in FIG.
A monitoring window 17 is provided in a part. The monitoring window 17 is hermetically closed with transparent glass. The monitoring window 17 observes a state in which the electrolyte 3 is injected into the case 1 in the airtight chamber 14.

The nozzle 9 is fixed to the upper surface of the closing cylinder 11. The nozzle 9 is provided to protrude downward from the upper surface of the closing cylinder 11. As shown in the enlarged sectional view of FIG. 9, the tip of the nozzle 9 projects the insertion tube 9a from the flange portion 9b, and the packing 18 is placed outside the insertion tube 9a.
Has been put. The packing 18 is sandwiched between the flange 9 b and the sealing plate 15 in a state where the nozzle 9 is connected to the small-diameter filling hole 2, and hermetically connects the nozzle tip to the small-diameter filling hole 2.

The nozzle 9 is connected via a connecting pipe 19 to an injection cylinder 20 arranged above. The injection cylinder 20 is located above the nozzle 9 and is fixed to the closing cylinder 11 in a vertical posture. The connection pipe 19 protrudes upward from the bottom surface of the injection cylinder 20. The connection pipe 19 protruding from the bottom surface of the injection cylinder 20 allows the electrolytic solution 3 filled in the injection cylinder 20 to be injected from the nozzle 9 only when the injection piston 12 is lowered. This is because the electrolytic solution 3 is not ejected from the nozzle 9 unless the electrolytic solution 3 is pushed up to the upper end of the connecting pipe 19. Therefore, with this structure, the electrolytic solution 3 can be injected from the injection cylinder 20 into the case 1 by controlling the movement of the injection piston 12 without providing a valve between the injection cylinder 20 and the nozzle 9.

The injection piston 12 is moved up and down by a piston up and down mechanism (not shown). Injection piston 12
Is inserted into the injection cylinder 20 and the electrolyte 3 filled in the injection cylinder 20 is pressed into the case 1 from the nozzle 9. Therefore, the injection piston 12 is inserted into the injection cylinder 20 without any gap. Injection piston 1 shown in the figure
2 has an O-ring 2 provided with a circumferential groove 12a at the lower end.
One is inserted. The O-ring 21 is connected to the injection cylinder 20
Of the injection cylinder 12 and the injection cylinder 20 are prevented from leaking. Injection cylinder 20
When filling a predetermined amount of the electrolyte 3 into the injection piston 12
Is raised to a position where it is withdrawn from the injection cylinder 20.

Further, the injection piston 12 is provided with an injection recess 12b into which the connecting pipe 19 is inserted when the injection piston 12 is lowered. The injection recess 12 b has an inner diameter slightly larger than the outer diameter of the connection pipe 19 so that a gap is formed between the injection recess 12 b and the connection pipe 19. When the injection piston 12 is lowered, the electrolyte 3 is passed through the gap between the connection pipe 19 and the injection recess 12 b to supply the electrolyte 3 of the injection cylinder 20 to the nozzle 9 from the upper end of the connection pipe 19. is there. The injection recess 12b is deeper than the connecting pipe 19 protrudes from the bottom surface of the injection cylinder 20 so that the injection piston 12 can descend most as shown in FIG.

Further, the closing cylinder 11 is provided in the airtight chamber 1.
In order to depressurize or pressurize 4, a nipple 22 is fixed, and a flexible hose 23 is connected to the nipple 22. The hose 23 is bifurcated, and the branch path is connected to a vacuum source 25 and a pressurized air source 26 via an on-off valve 24.

In the above apparatus, the electrolytic solution 3 is press-fitted into the case 1 and the small-diameter filling hole 2 is hermetically closed in the following steps. (1) As shown in FIG. 5, the case 1 is inserted into the fitting recess 10a of the base 10 and set. (2) With the injection piston 12 pulled out from the injection cylinder 20, the injection cylinder 20 is filled with a predetermined amount of the electrolytic solution 3. Thereafter, the injection piston 12 is inserted into the injection cylinder 20 and lowered. Injection piston 12
Is a position where the air filled in the injection cylinder 20 is almost completely exhausted. After the injection piston 12 descends and exhausts air from the injection cylinder 20, the descending of the injection piston 12 is stopped. However, the closing cylinder 11 waits at the raised position.

(3) As shown in FIG. 6, the closing cylinder 11 is lowered to the outside of the
An airtight chamber 14 is formed outside the case 1 by the base 1 and the base 10. At this time, the injection piston 12 is closed cylinder 1
Dropped with one. The lowering position of the closing cylinder 11 is such that an airtight chamber 14 is formed outside the case 1 and the nozzle 9
Is located above the small-diameter filling hole 2 of the sealing plate 15.

(4) With the on-off valve 24 connected to the pressurized air source 26 closed, the on-off valve 2 connected to the vacuum source 25 is closed.
4 is opened, and the pressure in the hermetic chamber 14 is reduced. At this time, the nozzle 9 is closed by the injection piston 12. The degree of vacuum in the hermetic chamber 14 for reducing the pressure is, for example, 10 to 100 torr, preferably about 50 torr. In this state, the air in the minute gap of the electrode group 4 inserted into the case 1 is forcibly exhausted.

(5) After the air in the case 1 is evacuated, the closing cylinder 11 is further lowered as shown in FIG. 7, and the tip of the nozzle 9 is brought into tight contact with the small-diameter filling hole 2. At this time, the injection piston 12 is
And does not cause relative movement between the injection piston 12 and the closing cylinder 11. After connecting the nozzle 9 to the small-diameter filling hole 2, the injection piston 12 is forcibly lowered,
The electrolyte 3 stored in the injection cylinder 20 is passed through the connecting pipe 19, the nozzle 9, and the small-diameter filling hole 2 in this order,
Press into case 1. The pressure at which the injection piston 12 presses the electrolyte 3 into the case 1 is, for example, 1.5 kg /
cm ² .

(6) When the injection piston 12 is lowered and the electrolytic solution 3 is press-fitted, or after the nozzle 9 is connected to the small-diameter filling hole 2, the on-off valve 24 connected to the vacuum source 25 is closed. On-off valve 2 closed and connected to a source of pressurized air 26
Open 4. In this state, the airtight chamber 14 is pressurized to a press pressure. The pressurized air source 26 sets the press pressure of the airtight chamber 14 higher than the internal pressure of the case 1 or substantially equal to the internal pressure of the case 1. For example, when the pressure inside the case 1 and 1.5 kg / cm ^2, pressing pressure of the airtight chamber 14, and 1.5~2kg / cm ^2. The pressure in the case 1 is highest immediately after the electrolyte 3 is injected, and gradually decreases as the electrolyte 3 penetrates into the gap between the electrode groups 4. Therefore, when the nozzle 9 is separated from the small-diameter filling hole 2, the electrolytic solution 3 flows from the case 1
4 is set to a pressure that does not blow. The case 1 when the nozzle 9 is separated from the small-diameter filling hole 2 by pressing the pressure of the airtight chamber 14
If the internal pressure is higher than the internal pressure, the electrolytic solution 3 does not erupt from the case 1. However, even if the press pressure of the airtight chamber 14 is substantially equal to the internal pressure of the case 1 but slightly lower, the electrolytic solution 3 does not blow out from the case 1.

Ideally, the press pressure of the hermetic chamber 14 is set as high as possible before the nozzle 9 is removed from the small-diameter filling hole 2 and before the electrolyte 3 permeates the electrode group 4.
This is because the electrolyte 3 can be reliably prevented from being injected from the small-diameter filling hole 2 and the electrolyte 3 can quickly and quickly penetrate the electrode group 4 in a short time. The method of setting the press pressure of the airtight chamber 14 higher than the internal pressure of the case 1 can be separated from the small-diameter filling hole 2 immediately after the nozzle 9 injects the electrolyte 3 into the case 1. Therefore, the time for connecting the nozzle 9 to the small-diameter filling hole 2 can be reduced. Further, after the nozzle 9 is removed, the electrolytic solution 3 can be forcibly pressed into the minute gap of the electrode group 4 by pressing the electrolytic solution 3 with the press pressure of the airtight chamber 14.
Permeation time can be shortened. After the electrolyte solution 3 has permeated the electrode group 4, the press pressure of the airtight chamber 14 is immediately reduced to near atmospheric pressure.

Thereafter, the closing cylinder 11 is raised to open the airtight chamber 14 to the atmosphere. When both closing valves 24 are closed and the closing cylinder 11 is raised, the airtight chamber 14 is closed.
Becomes large, the pressure in the airtight chamber 14 gradually decreases, and thereafter the airtight chamber 14 is opened to the atmosphere.

After raising the closing cylinder 11 to the position shown in FIG. 5, the case 1 is taken out from the base 10 and the small-diameter filling hole 2 is closed airtightly.

In the above filling method, the nozzle 9 is connected to the small-diameter filling hole 2 by moving the closing cylinder 11 up and down,
Also, it is separated from the small-diameter filling hole 2. In this method, since the nozzle 9 can be fixed to the closing cylinder 11, the structure for connecting the nozzle 9 to the closing cylinder 11 can be simplified. However, the nozzle is connected to the closed cylinder so that it can be moved up and down in an airtight state, and only the nozzle is moved up and down without moving the closed cylinder.
The nozzle may be connected to the small-diameter filling hole and may be separated from the small-diameter filling hole.

[0046]

According to the method of filling an electrolytic solution into a case from a small-diameter filling hole according to the present invention, an electrolytic solution can be press-fitted into a case from a small-diameter filling hole in a short time, and a nozzle for injecting an electrolytic solution can be provided from the small-diameter filling hole. There is a feature that when removed, the injected electrolyte can be reliably prevented from spouting from the small-diameter filling hole. According to the method of the present invention in which the electrolyte is injected into the case from the small-diameter filling hole by this method, the electrolyte can be pressed into the case at a considerably high pressure. For this reason, the injection time of the electrolyte can be drastically reduced. By the way, in the conventional method of injecting the electrolytic solution into the case of the lithium ion secondary battery without pressurizing, it took more than 30 seconds to inject the electrolytic solution.
It can be injected from a small-diameter filling hole in only 3 seconds. Further, when the nozzle is removed from the small-diameter filling hole, the pressurized state is maintained, so that the electrolytic solution press-fitted at this time does not blow out of the case. Can be maintained in a pressurized state continuously,
The electrolyte can also be forcibly penetrated into the electrode group in a short time. For this reason, the filling method of the present invention has a feature that the total time for injecting the electrolyte from the small-diameter filling hole into the case can be drastically reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a conventional method for filling an electrolytic solution into a case.

FIG. 2 is a cross-sectional view showing a method of filling a conventional case with an electrolytic solution.

FIG. 3 is a cross-sectional view showing another method of filling a conventional case with an electrolytic solution.

FIG. 4 is a cross-sectional view showing another method for filling a conventional case with an electrolytic solution.

FIG. 5 is a cross-sectional view of a filling device used in a method for filling an electrolytic solution according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view of a filling device used in a method for filling an electrolytic solution according to an embodiment of the present invention.

FIG. 7 is a cross-sectional view of a filling device used in a method for filling an electrolytic solution according to an embodiment of the present invention.

FIG. 8 is a cross-sectional view of a filling device used in a method for filling an electrolytic solution according to an embodiment of the present invention.

9 is an enlarged sectional view of a main part showing a tip of a nozzle of the apparatus shown in FIG. 7;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Case 2 ... Small diameter filling hole 3 ... Electrolyte solution 4 ... Electrode group 5 ... Filling chamber 6 ... Vacuum pump 7 ... Airtight chamber 8 ... Hopper 9 ... Nozzle 9a ... Insertion cylinder
9b ... flange 10 ... base 10a ... fitting recess
10b: sliding surface 11: closed cylinder 12: injection piston 12a: circumferential groove
12b Injection recess 13 O-ring 14 Airtight chamber 15 Sealing plate 16 Vertical guide 17 Monitoring window 18 Packing 19 Connection pipe 20 Injection cylinder 21 O-ring 22 Nipple 23 Hose 24 On-off valve 25 ... vacuum source 26 ... pressurized air source

Claims (2)

[Claims] An opening of a case (1) into which an electrode group (4) having a laminated structure is inserted is fitted to a sealing plate (1) having a small-diameter filling hole (2).
5), a predetermined amount of the electrolyte (3) is filled into the case (1) from the small-diameter filling hole (2), and the electrolyte (3) is filled in the gap between the electrode group (4).
In the electrolyte filling the small-diameter filling hole (2) of the case (1) and then closing the small-diameter filling hole (2) opened in the sealing plate (15).
Sealed with (14), nozzle (9) arranged in this airtight chamber (14)
Connected to the small-diameter filling hole (2), and the nozzle (9) to the case (1).
The electrolytic solution (3) pressurized into the inside is press-fitted, and the press pressure of the airtight chamber (14) outside the small-diameter filling hole (2) is almost equal to the internal pressure of the case (1) into which the electrolytic solution (3) is press-fitted. Equally or higher than the internal pressure of the case (1), remove the nozzle (9) from the small-diameter filling hole (2), and press the electrolyte solution into the case (1) with the press pressure of the airtight chamber (14). After preventing (3) from blowing out from the small-diameter filling hole (2), the airtight chamber (14) is opened to the atmospheric pressure with the electrolyte (3) not being injected from the small-diameter filling hole (2). A method of filling the case with the electrolytic solution through the small-diameter filling hole. 2. The pressure in the airtight chamber (14) is reduced to reduce the pressure in the case (1), and then the nozzle (9) is connected to the small-diameter filling hole (2).
2. The battery according to claim 1, wherein the electrolyte is filled in the electrolyte.
A method for filling an electrolyte solution into a case through a small-diameter filling hole described in the above item.