JP6977603B2 - Liquid injection device - Google Patents

Description

The present invention relates to a liquid injection device that injects an electrolytic solution into a battery case through a liquid injection hole in a battery manufacturing process.

In the process of manufacturing a battery, a liquid injection device for injecting an electrolytic solution into a battery case through a liquid injection hole is known. For example, Patent Document 1 discloses such a liquid injection device (see FIG. 4, claim 1 and the like in Patent Document 1). The liquid injection device of Patent Document 1 includes a liquid injection nozzle, and the liquid injection nozzle is inserted into the battery case through the liquid injection hole to inject the electrolytic solution into the battery case.

Japanese Unexamined Patent Publication No. 2014-22073

However, it has been found that in a battery in which an electrolytic solution is injected using a liquid injection device as described above, air bubbles are contained in the electrode body. It was also found that a battery containing air bubbles in the electrode body after injecting liquid has lower durability (prone to capacity deterioration) than a battery in which air bubbles are not contained in the electrode body after injecting liquid. I came.

The present invention has been made in view of the present situation, and an object of the present invention is to provide a liquid injection device capable of suppressing the inclusion of air bubbles in the electrode body of a battery after liquid injection.

One aspect of the present invention for solving the above problems is to electrolyze a battery case having a liquid injection hole and a battery having an electrode body housed in the battery case into the battery case through the liquid injection hole. A liquid injection device for injecting a liquid, which is inserted into the battery case through the vacuum chamber accommodating the battery, the vacuum pump for depressurizing the inside of the vacuum chamber, and the liquid injection hole, and into the battery case. A tubular metal injection nozzle for injecting the electrolytic solution and a gas provided upstream of the injection nozzle to degas the gas contained in the electrolytic solution supplied to the injection nozzle. An degassing device including a permeable film, an electrode inserted into the battery case through the injection hole and arranged at a distance from the injection nozzle, and the injected electrolyte solution are the injection nozzle and the injection nozzle. When the electrode comes into contact with the electrode, the conduction between the injection nozzle and the electrode is utilized to indicate that the liquid level of the injected electrolytic solution reaches the heights of the injection nozzle and the electrode. It is a liquid injection device including a detection unit for detecting.

Since the above-mentioned liquid injection device is provided with a degassing device upstream of the liquid injection nozzle, the degassed electrolytic solution can be injected into the battery case from the liquid injection nozzle. Therefore, as compared with the liquid injection device having no deaerator upstream of the liquid injection nozzle, it is possible to suppress the inclusion of air bubbles in the electrode body of the battery after the liquid injection.
In addition, the infusion device includes a vacuum chamber and a vacuum pump. Therefore, since the electrolytic solution can be injected into the battery case while depressurizing the inside of the vacuum chamber by operating the vacuum pump, it is possible to further suppress the inclusion of air bubbles in the electrode body of the battery after the injection. Further, after injecting a specified amount of electrolytic solution into the battery case, the pressure inside the vacuum chamber is reduced to degas the gas contained in the electrolytic solution already injected in the battery case and the gas contained in the electrode body. You can also do it. As a result, it is possible to more effectively suppress the inclusion of air bubbles in the electrode body of the battery after injection.

Further, this liquid injection device has the above-mentioned detection unit (liquid amount sensor) that detects the liquid level of the electrolytic solution in the battery case by the liquid injection nozzle and the electrode. Therefore, it is possible to detect the liquid level of the electrolytic solution at the time of injecting the electrolytic solution and prevent the electrolytic solution from overflowing from the battery case at the time of injecting the electrolytic solution. Further, it is possible to detect the liquid level of the electrolytic solution even when the degassing treatment by the above-mentioned depressurization is performed, and prevent the electrolytic solution from overflowing from the battery case during the degassing treatment. Moreover, as described above, since the electrolytic solution to be injected can be degassed in advance by the degassing device, it is possible to suppress the rise in the liquid level of the electrolytic solution at the time of injecting liquid or degassing by depressurization. Therefore, the degassing device, the injection nozzle, the electrode, and the detection unit prevent the electrolytic solution from overflowing from the battery case, and inject a specified amount of the electrolytic solution in a short time or depressurize the electrolytic solution. Qi processing can be performed.

Further, in this liquid injection device, the liquid injection nozzle also serves as one electrode of the liquid volume sensor. When inserting the completely separate injection nozzle and liquid volume sensor into the injection hole, it is necessary to insert the injection nozzle and a pair of electrodes into the injection hole. On the other hand, in this liquid injection device, it is sufficient to insert the liquid injection nozzle and one electrode into the liquid injection hole, so that the required opening size of the liquid injection hole can be reduced.

As the "liquid injection nozzle", for example, a liquid injection nozzle made of a material having high corrosion resistance such as platinum, tantalum, and stainless steel is preferable.
Examples of the "electrode" include a rod-shaped electrode such as a round bar, an elongated plate-shaped electrode, and a cylindrical electrode such as a cylinder. Further, an insulating pipe that insulates from the liquid injection nozzle may be provided around the radial direction of the electrode. Further, the electrode and the liquid injection nozzle may be integrated via an insulating member. Further, a cylindrical electrode can be coaxially arranged and integrated around the radial circumference of the liquid injection nozzle via a cylindrical insulating pipe. As the "electrode", a liquid injection nozzle made of a highly corrosion-resistant material such as platinum, tantalum, or stainless steel is preferable.

Examples of the method for injecting the electrolytic solution using the above-mentioned liquid injection device include the following methods. That is, the electrolytic solution is injected into the battery case while reducing the pressure in the vacuum chamber. At that time, if the liquid level of the electrolytic solution is detected by the liquid injection nozzle, the electrode, and the detection unit, the injection of the electrolytic solution is temporarily stopped, and a time is allowed until the liquid level of the electrolytic solution drops, or The pressure in the vacuum chamber is increased to lower the level of the electrolytic solution. After that, the injection of the electrolytic solution is restarted. A method of injecting a specified amount of the electrolytic solution into the battery case while suppressing the inclusion of air bubbles in the electrode by repeating this can be mentioned.

Alternatively, after that, the pressure inside the vacuum chamber is reduced to a predetermined pressure to degas the electrolytic solution already injected into the battery case and the gas contained in the electrode body. At that time, if the liquid level of the electrolytic solution is detected by the liquid injection nozzle, the electrode, and the detection unit, the depressurization in the vacuum chamber is temporarily stopped, and a time is allowed until the liquid level of the electrolytic solution drops. The air pressure in the vacuum chamber is increased to lower the level of the electrolytic solution. After that, the depressurization in the vacuum chamber is restarted. There is also a method of further suppressing the inclusion of air bubbles in the electrode by repeating this process and depressurizing the inside of the vacuum chamber to a predetermined atmospheric pressure to degas.

Further, in the liquid injection device, the detection unit applies an AC voltage between the liquid injection nozzle and the electrode to detect continuity between the liquid injection nozzle and the electrode. It is preferable to use a liquid device.

When a DC voltage is applied between the injection nozzle and the electrode, the electrolyte is electrolyzed when the injected electrolyte comes into contact with the injection nozzle and the electrode, and the injection nozzle or electrode on the negative electrode side There is a possibility that problems such as precipitation of Li metal or the like may occur on the surface. On the other hand, in the above-mentioned liquid injection device, since an AC voltage is applied between the liquid injection nozzle and the electrode, the liquid injection nozzle or the liquid injection nozzle or when the injected electrolytic solution comes into contact with the liquid injection nozzle and the electrode. It is possible to prevent problems such as the precipitation of Li metal or the like on the surface of the electrode.

It is a perspective view of the battery which concerns on embodiment. It is a vertical sectional view of the battery which concerns on embodiment. It is explanatory drawing of the liquid injection apparatus which concerns on embodiment. It is explanatory drawing which magnified and shows the tip side part of the injection nozzle and the electrode inserted in the injection hole of a battery among the injection apparatus which concerns on embodiment. It is explanatory drawing which shows the degassing apparatus among the liquid injection apparatus which concerns on embodiment. It is a flowchart of the liquid injection process among the manufacturing methods of the battery which concerns on embodiment. It is a flowchart of a predetermined amount injection process subroutine according to an embodiment. It is a flowchart of the post-injection degassing process subroutine according to the embodiment. It is explanatory drawing which magnified and shows the tip side part of the injection nozzle and the electrode inserted in the injection hole of a battery among the injection apparatus which concerns on the modification 1. It is explanatory drawing which magnified and shows the tip side part of the injection nozzle and the electrode inserted in the injection hole of a battery among the injection apparatus which concerns on the modification 2.

(Embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a perspective view and a vertical sectional view of the battery 1 according to the present embodiment. In the following, the vertical direction BH, the horizontal direction CH, and the thickness direction DH of the battery 1 will be described as the directions shown in FIGS. 1 and 2. The battery 1 is a square and sealed lithium-ion secondary battery mounted on a vehicle such as a hybrid car, a plug-in hybrid car, or an electric vehicle. The battery 1 is composed of a battery case 10, an electrode body 20 housed therein, a positive electrode terminal member 50 and a negative electrode terminal member 60 supported by the battery case 10 (see FIGS. 1 and 2). Further, the electrolytic solution 15 is housed in the battery case 10, a part thereof is impregnated in the electrode body 20, and a part thereof is accumulated in the bottom of the battery case 10.

Of these, the battery case 10 has a rectangular parallelepiped shape and is made of metal (aluminum in this embodiment). The battery case 10 is composed of a bottomed square cylindrical case body member 11 having an opening only on the upper side, and a rectangular plate-shaped case lid member 13 welded in a form of closing the opening of the case body member 11. Ru. The case lid member 13 is provided with a liquid injection hole 13h, and is hermetically sealed by the sealing member 17. The liquid injection hole 13h is used when the electrolytic solution 15 is injected into the battery case 10, as will be described later.

Further, a positive electrode terminal member 50 made of aluminum is fixed to the case lid member 13 in a state of being insulated from the case lid member 13. The positive electrode terminal member 50 is connected to and conductive on the positive electrode plate 21 of the electrode body 20 in the battery case 10, while penetrating the case lid member 13 and extending to the outside of the battery. Further, a negative electrode terminal member 60 made of copper is fixed to the case lid member 13 in a state of being insulated from the case lid member 13. The negative electrode terminal member 60 is connected to and conductive on the negative electrode plate 31 of the electrode body 20 in the battery case 10, while penetrating the case lid member 13 and extending to the outside of the battery.

The electrode body 20 has a flat shape and is housed in the battery case 10 in a state of being laid on its side. A bag-shaped insulating film enclosing body 19 made of an insulating film is arranged between the electrode body 20 and the battery case 10. The electrode body 20 is formed by stacking a band-shaped positive electrode plate 21 and a band-shaped negative electrode plate 31 on each other via a pair of band-shaped separators 41 and 41 and winding them flat around an axis.

Next, a method for manufacturing the battery 1 will be described. First, in the "assembly process", the battery 1 is assembled. Specifically, the positive electrode plate 21 and the negative electrode plate 31 are wound on top of each other via a pair of separators 41 and 41 and compressed into a flat shape to form an electrode body 20. Next, the case lid member 13 is prepared, and the positive electrode terminal member 50 and the negative electrode terminal member 60 are fixedly attached to the case lid member 13 (see FIGS. 1 and 2). After that, the positive electrode terminal member 50 and the negative electrode terminal member 60 are welded to the positive electrode plate 21 and the negative electrode plate 31 of the electrode body 20, respectively. Next, the electrode body 20 is covered with the insulating film enclosing body 19, and these are inserted into the case main body member 11, and the opening of the case main body member 11 is closed with the case lid member 13. Then, the case body member 11 and the case lid member 13 are welded to form the battery case 10.

Next, a "liquid injection step" is performed (see FIGS. 6 to 8), and a specified amount of the electrolytic solution 15 is injected into the battery case 10 through the liquid injection holes 13h provided in the case lid member 13, and the electrolytic solution 15 is injected. Is impregnated into the electrode body 20. This liquid injection step is performed using the liquid injection device 100 shown in FIGS. 3 to 5. The liquid injection device 100 includes a vacuum chamber 140, a first vacuum pump 145, a liquid injection nozzle 110, an electrode 120, a detection device (detection unit) 130, an electrolytic solution tank 150, a vacuum degassing module (degassing device) 160, and a control. It is composed of a device 170 and the like.

Of these, the vacuum chamber 140 is composed of a bottomed square cylinder-shaped chamber body member 141 having an opening only on the upper side, and a rectangular plate-shaped chamber lid member 143 that closes the opening of the chamber body member 141. The battery 1 is housed inside the vacuum chamber 140. A first vacuum pump 145 is attached to the vacuum chamber 140, and by operating the first vacuum pump 145, the inside of the vacuum chamber 140 can be depressurized. Further, an atmosphere opening valve 147 is attached to the vacuum chamber 140, and the inside of the vacuum chamber 140 can be opened to the atmosphere by opening the atmosphere opening valve 147. Further, a pressure sensor 149 is attached to the vacuum chamber 140, and the air pressure in the vacuum chamber 140 can be measured by the pressure sensor 149. Further, in the chamber lid member 143 of the vacuum chamber 140, a liquid injection nozzle 110 and an electrode 120 are fixedly attached with a predetermined interval KC (see FIG. 4).

The liquid injection nozzle 110 is cylindrical and made of metal (specifically, stainless steel). The electrolytic solution 15 flows through the inside of the liquid injection nozzle 110, and the electrolytic solution 15 is discharged from the tip portion 110s of the liquid injection nozzle 110. The liquid injection nozzle 110 is fixed perpendicular to the chamber lid member 143 so that its extension direction is parallel to the vertical direction FH of the vacuum chamber 140.

The electrode 120 has a round bar shape and is made of metal (specifically, stainless steel). Except for the tip portion 120s of the electrode 120, the radial periphery of the electrode 120 is covered with an insulating pipe 121. The electrode 120 and the insulating pipe 121 are fixedly fixed perpendicularly to the chamber lid member 143 so that the extending direction thereof is parallel to the vertical direction FH and parallel to the liquid injection nozzle 110. As a result, the tip portion 120s of the electrode 120 and the liquid injection nozzle 110 are arranged with a predetermined interval KC.

The detection device 130 is electrically connected to the liquid injection nozzle 110 via the wiring 131 and to the electrode 120 via the wiring 133, which constitutes the liquid volume sensor 105. The detection device 130 utilizes the fact that when the injected electrolytic solution 15 comes into contact with the injection nozzle 110 and the electrode 120, the injection nozzle 110 and the electrode 120 are electrically connected to each other, so that the injected electrolytic solution 15 is used. It is a device for detecting that the liquid level of 15 m has reached the height of the liquid injection nozzle 110 and the electrode 120. Specifically, the detection device 130 applies an AC voltage between the injection nozzle 110 and the electrode 120, and detects the current flowing between the injection nozzle 110 and the electrode 120 when the electrolytic solution 15 comes into contact with each other. As a result, it is detected that the liquid level 15 m of the injected electrolytic solution 15 has reached the heights of the injection nozzle 110 and the electrode 120, and this detection signal can be output.

The electrolytic solution tank 150 is a tank for storing the electrolytic solution 15, and is connected to the base end portion 110t of the liquid injection nozzle 110 via the liquid flow passage 151. A flow meter 153, a liquid injection valve 155, and a vacuum degassing module 160 are arranged in the middle of the liquid flow passage 151, respectively. Since the flow meter 153 can measure the amount of the electrolytic solution 15 flowing through the liquid flow passage 151, the amount of the electrolytic solution 15 discharged from the tip portion 110s of the injection nozzle 110 and injected into the battery case 10. Can be measured. When the liquid injection valve 155 is opened, the electrolytic liquid 15 flows through the liquid flow passage 151, the electrolytic liquid 15 is supplied to the liquid injection nozzle 110, and the electrolytic liquid is supplied from the tip portion 110s of the liquid injection nozzle 110. 15 is released. On the other hand, when the liquid injection valve 155 is closed, the flow of the electrolytic liquid 15 in the liquid flow passage 151 is stopped, so that the discharge (liquid injection) of the electrolytic liquid 15 from the tip portion 110s of the liquid injection nozzle 110 is also stopped.

Further, the vacuum degassing module 160 (see FIG. 5) has a cylindrical housing case 161 and a gas permeable membrane 163 of a plurality of resin hollow fibers housed therein. At one end of the housing case 161 in the axial direction (upper in FIG. 5), a first opening 161a for allowing the electrolytic solution 15 to flow from the outside to the inside of the housing case 161 is provided, and the other end in the axial direction is provided. (Upper side in FIG. 5) is provided with a second opening 161b for allowing the electrolytic solution 15 to flow out from the inside of the housing case 161 to the outside. Then, in this vacuum degassing module 160, the electrolytic solution 15 that has flowed into the housing case 161 through the first opening 161a circulates inside each gas permeation membrane 163, and passes through the second opening 161b to the housing case. It is configured to leak to the outside of 161.

A third opening 161c is provided on the side of the housing case 161, and a second vacuum pump 165 (see FIG. 3) is connected to the third opening 161c. When the electrolytic solution 15 is circulated in each gas permeation film 163 as described above while operating the second vacuum pump 165 to reduce the pressure in the housing case 161, the gas contained in the electrolytic solution 15 becomes a gas. It penetrates the permeable film 163 and is discharged to the outside of the gas permeable film 163, and is further discharged to the outside of the housing case 161 through the third opening 161c. In this way, the gas contained in the electrolytic solution 15 is degassed.

The control device 170 includes a CPU, ROM and RAM (not shown), and has a microcomputer operated by a predetermined control program stored in the ROM or the like. A detection device 130, a pressure sensor 149, a flow meter 153, a first vacuum pump 145, an atmosphere release valve 147, a second vacuum pump 165, and a liquid injection valve 155 are connected to the control device 170, respectively. As will be described later, the control device 170 operates the first vacuum pump 145, opens and closes the atmosphere release valve 147, and the second vacuum pump 165 based on the detection signals of the detection device 130, the pressure sensor 149, and the flow meter 153. It controls the operation and the opening and closing of the liquid injection valve 155, respectively.

Next, the control of the control device 170 in the liquid injection process using the liquid injection device 100 will be described with reference to the flowcharts of FIGS. 6 to 8. Prior to the liquid injection step, the above-mentioned battery 1 is placed in a predetermined position in the chamber body member 141 of the vacuum chamber 140 in a state where the battery 1 is erected so that the vertical BH of the battery 1 is parallel to the vertical FH. Place. After that, the opening of the chamber body member 141 is closed by the chamber lid member 143, and the liquid injection nozzle 110 and the electrode 120 fixed to the chamber lid member 143 are inserted into the battery case 10 through the liquid injection hole 13h of the battery 1. (See FIGS. 3 and 4).

Then, in step S1, a specified amount of liquid injection step is performed (see FIG. 6). That is, the process proceeds to the specified amount injection process subroutine shown in FIG. 7, and first, in step S11, the control device 170 closes the atmosphere release valve 147.
After that, the process proceeds to step S12, and the first vacuum pump 145 is operated to reduce the pressure in the vacuum chamber 140. The second vacuum pump 165 is also operated to reduce the pressure inside the housing case 161 of the vacuum degassing module 160.
After that, the process proceeds to step S13, and it is determined whether or not the atmospheric pressure in the vacuum chamber 140 measured by the pressure sensor 149 has been reduced to a predetermined atmospheric pressure (10 kPa (abs) in this embodiment). Here, NO, that is, when the pressure inside the vacuum chamber 140 has not been reduced to the predetermined pressure, this step S13 is repeated and the inside of the vacuum chamber 140 waits until the pressure drops to the predetermined pressure.

On the other hand, if YES in step S13, that is, when the pressure inside the vacuum chamber 140 is reduced to a predetermined atmospheric pressure, the process proceeds to step S14 to start pouring the electrolytic solution 15 into the battery case 10. That is, the control device 170 opens the injection valve 155 when it is determined that the atmospheric pressure in the vacuum chamber 140 measured by the pressure sensor 149 is equal to or lower than the predetermined atmospheric pressure. As a result, the electrolytic solution 15 stored in the electrolytic solution tank 150 is supplied to the liquid injection nozzle 110 through the liquid flow passage 151, and the electrolytic solution 15 is discharged into the battery case 10 from the tip portion 110s of the liquid injection nozzle 110. At that time, since the vacuum degassing module 160 is installed in the liquid flow passage 151, the gas contained in the electrolytic solution 15 supplied to the liquid injection nozzle 110 can be degassed.

Next, in step S15, it is determined whether or not the liquid level 15 m of the electrolytic solution 15 reaches the heights of the liquid injection nozzle 110 and the electrode 120. Specifically, when the liquid level 15 m of the electrolytic solution 15 reaches the height of the liquid injection nozzle 110 and the electrode 120, the detection device 130 of the liquid volume sensor 105 transfers the current flowing between the liquid injection nozzle 110 and the electrode 120. It is detected and this detection signal is output to the control device 170. As a result, the control device 170 determines that the liquid level 15 m of the electrolytic solution 15 has reached the heights of the liquid injection nozzle 110 and the electrode 120. Since the electrolytic solution 15 to be injected is degassed in advance by the vacuum degassing module 160, the rise of the liquid level 15 m of the electrolytic solution 15 at the time of injecting liquid is suppressed.

If it is determined in step S15 that NO, that is, the liquid level 15 m of the electrolytic solution 15 has not reached the heights of the injection nozzle 110 and the electrode 120, the process proceeds to step S21 and the injection amount of the electrolytic solution 15 is reached. Determines if the specified amount has been reached. Specifically, in the control device 170, the flow rate of the electrolytic solution 15 flowing through the liquid flow passage 151 measured by the flow meter 153, that is, the liquid amount of the electrolytic solution 15 injected into the battery 1 is a specified amount. Judge whether or not it has reached. If it is determined in step S21 that NO, that is, the injection amount of the electrolytic solution 15 has not reached the specified amount, the process returns to step S15.

On the other hand, if YES in step S15 described above, that is, if it is determined that the liquid level 15 m of the electrolytic solution 15 has reached the heights of the injection nozzle 110 and the electrode 120, the process proceeds to step S16 and the injection of the electrolytic solution 15 is performed. Stop once. Specifically, the control device 170 closes the liquid injection valve 155, stops the flow of the electrolytic solution 15 flowing in the liquid flow passage 151, and stops the injection of the electrolytic solution 15 into the battery case 10. This makes it possible to prevent the electrolytic solution 15 from overflowing to the outside of the battery from the liquid injection hole 13h during liquid injection.

After step S16, the process proceeds to step S17, and the control device 170 opens the atmosphere release valve 147 to increase the air pressure in the vacuum chamber 140. As a result, the impregnation of the injected electrolytic solution 15 into the electrode body 20 is promoted, so that the liquid level 15 m of the electrolytic solution 15 gradually decreases.

Next, the process proceeds to step S18, and in the same manner as in step S15, it is determined whether or not the liquid level 15 m of the electrolytic solution 15 reaches the heights of the liquid injection nozzle 110 and the electrode 120. Here, YES, that is, when the liquid level 15 m of the electrolytic solution 15 has reached the heights of the injection nozzle 110 and the electrode 120, this step S18 is repeated to raise the liquid level 15 m of the electrolytic solution 15. Wait until the height drops so that it does not come into contact with the liquid injection nozzle 110 and the electrode 120.

Next, if it is determined in step S18 that NO, that is, the liquid level 15 m of the electrolytic solution 15 has not reached the heights of the injection nozzle 110 and the electrode 120, the process proceeds to step S19 and the atmosphere release valve 147 is performed. Close. When the liquid level 15 m of the electrolytic solution 15 is lowered and a part of the electrode body 20 protrudes from the liquid level 15 m of the electrolytic solution 15, air easily enters the inside of the electrode body 20. Therefore, when the post-injection degassing step (step S3) described later is not performed, air bubbles are likely to be contained in the electrode body 20 of the battery 1 after the infusion.

Next, the process proceeds to step S20, the liquid injection valve 155 is opened, and the injection of the electrolytic solution 15 into the battery case 10 is restarted. When the liquid level 15 m of the electrolytic solution 15 reaches the heights of the liquid injection nozzle 110 and the electrode 120 in this way, the injection of the electrolytic solution 15 is temporarily stopped, and the liquid level 15 m of the electrolytic solution 15 is lowered before pouring. Resume the liquid.
The injection of the electrolytic solution 15 started in step S14 described above waits for the atmospheric pressure in the vacuum chamber 140 to be reduced to a predetermined atmospheric pressure (10 kPa (abs) in this embodiment) in the previous step S13. I'm going from. On the other hand, since the injection of the electrolytic solution 15 restarted in step S20 is performed immediately after the atmosphere opening valve 147 is closed in step S19, the atmospheric pressure in the vacuum chamber 140 is the above-mentioned predetermined atmospheric pressure (10 kPa (abs). )) Higher (eg, 20-30 kPa (abs)).

Next, the process proceeds to step S21 described above, and if YES, that is, when it is determined that the injection amount of the electrolytic solution 15 has reached the specified amount, the process proceeds to step S22 and the injection of the electrolytic solution 15 is completed. Specifically, the control device 170 closes the liquid injection valve 155, stops the flow of the electrolytic liquid 15 flowing in the liquid flow passage 151, stops the supply of the electrolytic liquid 15 to the liquid injection nozzle 110, and causes the battery case. The injection of the electrolytic solution 15 into the 10 is completed. By doing so, it is possible to inject a predetermined amount of the electrolytic solution 15 while preventing the electrolytic solution 15 from overflowing to the outside of the battery from the injection hole 13h. Thus, the specified amount injection step (step S1) is completed.

After the specified amount injection step (step S1), a post-injection degassing step (step S3) is performed (see FIG. 6). That is, the process proceeds to the post-injection degassing process subroutine shown in FIG. 8, and in step S31, the liquid level 15 m of the electrolytic solution 15 is the height of the injection nozzle 110 and the electrode 120 in the same manner as in steps S15 and S18 described above. Determine if it has reached that point. Since the electrolytic solution 15 to be injected is degassed in advance by the vacuum degassing module 160, the rise of the liquid level 15 m of the electrolytic solution 15 in the post-injection degassing step (step S3) is suppressed. ..
Here, if it is determined that NO, that is, the liquid level 15 m of the electrolytic solution 15 has not reached the heights of the injection nozzle 110 and the electrode 120, the process proceeds to step S35, and the vacuum chamber 140 is the same as in step S13. It is determined whether or not the atmospheric pressure inside has been reduced to a predetermined atmospheric pressure (10 kPa (abs) in this embodiment). Here, NO, that is, when the pressure inside the vacuum chamber 140 is not reduced to a predetermined atmospheric pressure, the process returns to step S31.

On the other hand, if YES in step S31 described above, that is, if it is determined that the liquid level 15 m of the electrolytic solution 15 has reached the heights of the injection nozzle 110 and the electrode 120, the process proceeds to step S32, and the control device 170 enters the atmosphere. The open valve 147 is opened to increase the air pressure in the vacuum chamber 140. As a result, the liquid level 15 m of the electrolytic solution 15 gradually decreases.

Next, the process proceeds to step S33, and in the same manner as in step S31, it is determined whether or not the liquid level 15 m of the electrolytic solution 15 reaches the heights of the liquid injection nozzle 110 and the electrode 120. Here, YES, that is, when the liquid level 15 m of the electrolytic solution 15 has reached the heights of the injection nozzle 110 and the electrode 120, this step S33 is repeated to raise the liquid level 15 m of the electrolytic solution 15. Wait until the height drops so that it does not come into contact with the liquid injection nozzle 110 and the electrode 120.

Next, if it is determined in step S33 that NO, that is, the liquid level 15 m of the electrolytic solution 15 has not reached the heights of the injection nozzle 110 and the electrode 120, the process proceeds to step S34 and the atmosphere release valve 147 is performed. Close.
Next, the process proceeds to step S35 described above, and if YES, that is, when the atmospheric pressure in the vacuum chamber 140 is reduced to a predetermined atmospheric pressure (10 kPa (abs) in this embodiment), the process proceeds to step S36. By reducing the pressure in the vacuum chamber 140 to a predetermined atmospheric pressure again in this way, the gas contained in the injected electrolytic solution 15 and the gas contained in the electrode body 20 can be degassed.

Then, in step S36, the control device 170 stops the operation of the first vacuum pump 145. After that, the process proceeds to step S37, and the control device 170 opens the atmosphere release valve 147 to return the inside of the vacuum chamber 140 to atmospheric pressure. Thus, the post-injection degassing step (step S3) is completed. After that, the chamber lid member 143 is removed from the chamber main body member 141, and the liquid injection nozzle 110 and the electrode 120 fixedly attached to the chamber lid member 143 are taken out from the liquid injection hole 13h of the battery 1. After that, the battery 1 is taken out from the chamber main body member 141. Thus, the liquid injection process is completed.
After the liquid injection step is completed, the liquid injection hole 13h is sealed with the sealing member 17 in the “sealing step”. After that, the battery 1 is charged for the first time. In addition, various inspections are performed on this battery 1. Thus, the battery 1 is completed.

(Examples and comparative examples)
Next, the results of the tests conducted to verify the effect of the present invention will be described. As an example, the liquid injection step was performed in the same manner as in the embodiment, and the battery 1 similar to the embodiment was manufactured. That is, in the liquid injection step, the electrolytic solution 15 before the liquid injection was degassed by the vacuum degassing module (degassing device) 160 arranged upstream of the liquid injection nozzle 110 (see Table 1). Further, in the specified amount injection step (step S1), the electrolytic solution 15 was injected under reduced pressure while detecting the liquid level 15 m of the electrolytic solution 15 using the liquid amount sensor 105. Further, after the specified amount injection step (step S1), the deaeration process after the injection (post-injection deaeration step (step S3)) is performed while detecting the liquid level 15 m of the electrolytic solution 15 using the liquid amount sensor 105. ) Was performed.

If the electrolytic solution 15 is injected without using the liquid amount sensor 105 in the specified amount injection step (step S1), the electrolytic solution 15 may overflow from the battery case 10. Therefore, it is not preferable to inject the electrolytic solution 15 without using the liquid amount sensor 105.
Further, even when the degassing process is performed without using the liquid amount sensor 105 in the degassing step after pouring (step S3), the electrolytic solution 15 may overflow from the battery case 10. Therefore, it is not preferable to perform the degassing step (step S3) after injecting the liquid without using the liquid amount sensor 105.

On the other hand, in Comparative Example 1, the electrolytic solution 15 before the injection was injected with the electrolytic solution 15 without being degassed by the vacuum degassing module 160. Other than that, the battery 1 was manufactured by performing the liquid injection step in the same manner as in the examples.
In Comparative Example 2, in the specified amount injection step (step S1), the electrolytic solution 15 was injected under atmospheric pressure without reducing the pressure in the vacuum chamber 140. Other than that, the battery 1 was manufactured by performing the liquid injection step in the same manner as in the examples.
In Comparative Example 3, the post-injection degassing step (step S3) was not performed after the specified amount injecting step (step S1). Other than that, the battery 1 was manufactured by performing the liquid injection step in the same manner as in the examples.

Next, for each of the batteries 1 of Examples and Comparative Examples 1 to 3, the manufactured battery 1 is disassembled and the negative electrode plate 31 is taken out, and whether or not foamy Li precipitation occurs on the surface of the negative electrode plate 31. Was visually investigated. The results are shown in Table 1. It has been found that in the battery 1 in which foam-like Li precipitation occurs on the surface of the negative electrode plate 31, the durability performance of the battery is low (capacity deterioration is likely to occur).

In each of the batteries 1 of Comparative Examples 1 to 3, foamy Li precipitation occurred on the surface of the negative electrode plate 31, whereas in the battery 1 of the embodiment, such foamy Li was generated on the surface of the negative electrode plate 31. No precipitation occurred. The reason for this result is considered to be as follows.
In Comparative Example 1, the electrolytic solution 15 before the injection was not degassed by the vacuum degassing module 160. Therefore, the degassing was not sufficient, and the gas remaining in the electrolytic solution 15 caused foamy Li precipitation on the surface of the negative electrode plate 31.
Further, in Comparative Example 2, in the specified amount injection step (step S1), the electrolytic solution 15 is injected under atmospheric pressure. Therefore, air entered into the electrolytic solution 15 and the electrode body 20 at the time of injecting the liquid, which caused foamy Li precipitation on the surface of the negative electrode plate 31.

Further, in Comparative Example 3, the post-injection degassing step (step S3) is not performed after the specified amount injecting step (step S1). Therefore, it is considered that the degassing was not sufficient and the gas contained in the electrolytic solution 15 and the electrode body 20 caused foamy Li precipitation on the surface of the negative electrode plate 31.
On the other hand, in the embodiment, the electrolytic solution 15 before the injection is degassed by the vacuum degassing module 160, and the electrolytic solution 15 is injected under reduced pressure in the specified amount injection step (step S1). In addition, a predetermined amount of liquid injection step (step S1) is followed by a liquid injection and then degassing step (step S3). Therefore, it is considered that the electrolytic solution 15 and the electrode body 20 were sufficiently degassed, so that foamy Li precipitation did not occur on the surface of the negative electrode plate 31.

As described above, since the liquid injection device 100 includes the vacuum degassing module 160 upstream of the liquid injection nozzle 110, the degassed electrolytic solution 15 is poured into the battery case 10 from the liquid injection nozzle 110. Can be liquid. Therefore, as compared with the liquid injection device having no deaerator upstream of the liquid injection nozzle 110, it is possible to suppress the inclusion of air bubbles in the electrode body 20 of the battery 1 after the liquid injection.
In addition, the liquid injection device 100 includes a vacuum chamber 140 and a first vacuum pump 145. Therefore, since the electrolytic solution 15 can be injected into the battery case 10 while depressurizing the inside of the vacuum chamber 140 by operating the first vacuum pump 145, bubbles are contained in the electrode body 20 of the battery 1 after the injection. It can be further suppressed. Further, after injecting a specified amount of the electrolytic solution 15 into the battery case 10, the vacuum chamber 140 is depressurized so that the gas contained in the electrolytic solution 15 already injected into the battery case 10 and the inside of the electrode body 20 are contained. The gas contained in can be degassed. As a result, it is possible to more effectively suppress the inclusion of air bubbles in the electrode body 20 of the battery 1 after the liquid injection.

Further, the liquid injection device 100 has a detection device 130 that detects the liquid level 15 m of the electrolytic solution 15 in the battery case 10 by the liquid injection nozzle 110 and the electrode 120. Therefore, it is possible to detect the liquid level 15 m of the electrolytic solution 15 at the time of injecting the electrolytic solution 15 and prevent the electrolytic solution 15 from overflowing from the battery case 10 at the time of injecting the electrolytic solution 15. Further, the liquid level 15 m of the electrolytic solution 15 is detected even when the degassing process by depressurization (the degassing step after injection (step S3)) is performed, and the electrolytic solution 15 is used as the battery case during the degassing process. It can also be prevented from overflowing from 10. Moreover, since the electrolytic solution 15 to be injected can be degassed in advance by the vacuum degassing module 160, the liquid level of the electrolytic solution 15 at the time of injecting liquid or degassing by depressurization (post-injection degassing step) is 15 m. The rise can be suppressed. Therefore, the vacuum degassing module 160, the injection nozzle 110, the electrode 120, and the detection device 130 prevent the electrolytic solution 15 from overflowing from the battery case 10, and the electrolytic solution 15 is supplied in a specified amount in a short time. It is possible to inject liquid or perform degassing treatment by depressurizing (post-injection degassing step).

Further, in the liquid injection device 100, the liquid injection nozzle 110 also serves as one electrode of the liquid volume sensor 105. When inserting the completely separate injection nozzle 110 and the liquid volume sensor 105 into the injection hole 13h, it is necessary to insert the injection nozzle 110 and the pair of electrodes into the injection hole 13h. .. On the other hand, in the liquid injection device 100, it is sufficient to insert the liquid injection nozzle 110 and one electrode 120 into the liquid injection hole 13h, so that the required opening size of the liquid injection hole 13h can be reduced.

Further, since the liquid injection device 100 of the present embodiment applies an AC voltage between the liquid injection nozzle 110 and the electrode 120, the injected electrolytic solution 15 comes into contact with the liquid injection nozzle 110 and the electrode 120. Occasionally, it is possible to prevent a problem that Li metal is deposited on the surface of the liquid injection nozzle 110 or the electrode 120.

(Deformation form 1)
Next, a first modification of the above embodiment will be described. In the liquid injection device 100 of the embodiment, the radial circumference of the portion of the electrode 120 excluding the tip portion 120s is covered with the insulating pipe 121 (see FIG. 4). On the other hand, the liquid injection device 200 of the present modified embodiment 1 has a round bar-shaped electrode 220 similar to that of the embodiment, except that the electrode 220 is not covered with an insulating pipe (see FIG. 9). Also in the present modification 1, the detection device 130 applies an AC voltage between the injection nozzle 110 and the electrode 220, and causes a current flowing between the injection nozzle 110 and the electrode 220 when the electrolytic solution 15 comes into contact with the detection device 130. By detecting, it is possible to detect that the liquid level 15 m of the electrolytic solution 15 has reached the heights of the liquid injection nozzle 110 and the electrode 220. In addition, other parts similar to those in the embodiment have the same effects.

(Deformation form 2)
Next, a second modification of the above embodiment will be described. In the liquid injection device 100 of the embodiment, the liquid injection nozzle 110 and the electrode 120 are separate bodies (see FIG. 4). On the other hand, the liquid injection device 300 of the present modification 2 is different in that the liquid injection nozzle 110 and the electrode 320 are integrated (see FIG. 10). Specifically, in the present modification 2, the liquid injection nozzle 110 is covered with an insulating pipe 321 around the radial direction of the liquid injection nozzle 110 except for the tip portion 110s. Further, a cylindrical electrode 320 is arranged coaxially with the liquid injection nozzle 110 and the insulating pipe 321 around the radial direction of the insulating pipe 321, and the liquid injection nozzle 110, the insulating pipe 321 and the electrode 320 are integrated. Has been done.

By integrating the liquid injection nozzle 110, the insulating pipe 321 and the electrode 320 in this way, as compared with the case where the liquid injection nozzle 110 and the electrodes 120 and 220 are separate bodies as in the embodiment and the modified form 1, The liquid injection nozzle 110 and the electrode 320 can be easily handled. Further, also in the present modification 2, the detection device 130 applies an AC voltage between the injection nozzle 110 and the electrode 320, and flows between the injection nozzle 110 and the electrode 320 when the electrolytic solution 15 comes into contact with the detection device 130. By detecting the current, it is possible to detect that the liquid level 15 m of the electrolytic solution 15 has reached the heights of the liquid injection nozzle 110 and the electrode 320. In addition, other parts similar to those in the embodiment have the same effects.

In the above, the present invention has been described in accordance with the embodiments and modifications 1 and 2, but the present invention is not limited to the above-described embodiments and variants 1 and 2, and is not deviating from the gist thereof. Needless to say, it can be changed and applied as appropriate.
For example, the detection device 130 of the embodiment or the like detects the current flowing between the injection nozzle 110 and the electrodes 120, 220, 320 when the electrolytic solution 15 comes into contact with the injection nozzle 110 and the electrode 120. , 220, 320 may be detected.

Further, in the embodiment or the like, a flow meter 153 is arranged in a liquid flow passage 151 connecting the electrolytic solution tank 150 and the liquid injection nozzle 110, and the flow meter 153 is used to inject the electrolytic solution 15 into the battery case 10. The liquid volume was measured, but it is not limited to this. For example, instead of the flow meter 153, a weight scale is installed in the chamber main body member 141, and the battery 1 is placed on the weight scale. Then, the amount of the electrolytic solution 15 injected into the battery case 10 can be measured with this weighing scale.

1 Battery 10 Battery case 13h Injection hole 15 Electrolyte 15m (of electrolyte) Liquid level 20 Electrode body 100, 200, 300 Injection device 105 Liquid volume sensor 110 Injection nozzle 120, 220, 320 Electrode 130 Detection device (detection) Department)
140 Vacuum chamber 145 1st vacuum pump 147 Atmospheric release valve 149 Pressure sensor 150 Electrolyte tank 153 Flow meter 155 Injection valve 160 Degassing device (vacuum degassing module)
170 Controller KC Interval

Claims (1)

A battery case having a liquid injection hole and a battery having an electrode body housed in the battery case, which is a liquid injection device for injecting an electrolytic solution into the battery case through the liquid injection hole.
The vacuum chamber that houses the above batteries and
A vacuum pump that decompresses the inside of the vacuum chamber and
A tubular metal injection nozzle that is inserted into the battery case through the injection hole and injects the electrolytic solution into the battery case.
An degassing device including a gas permeable membrane, which is provided upstream from the injection nozzle and degass the gas contained in the electrolytic solution supplied to the injection nozzle.
An electrode inserted into the battery case through the liquid injection hole and arranged at a distance from the liquid injection nozzle,
When the injected electrolytic solution comes into contact with the injection nozzle and the electrode, the liquid level of the injected electrolytic solution becomes the above by utilizing the conduction between the injection nozzle and the electrode. A liquid injection device including a liquid injection nozzle and a detection unit that detects that the height of the electrode has been reached.

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