Liquid injection device and liquid injection method

Abstract

To simplify a configuration for reducing a pressure and injecting electrolyte into a storage battery.SOLUTION: An injection method includes the steps of inserting a nozzle portion 11 of an injection syringe 10, which has an injection port 12 for supplying an electrolyte solution EL into the inside of an outer can and a suction port 14 connected to a suction path 15 connected to an external pump VP for depressurizing the outer can 2, into a cell opening 5 opened in the outer can 2, reducing the pressure inside the outer can 2 through the suction port 14 and the suction path 15, supplying the electrolyte solution EL to a liquid reservoir chamber 13 airtightly separated from the suction path 15 within the injection syringe 10, reducing the pressure of the liquid reservoir chamber 13 separately from the inside of the outer can 2, operating a volume variable mechanism 16 provided on the suction path 15 within the injection syringe 10 to expand the volume of the suction path 15 to further reduce the pressure inside the outer can 2, which is connected to the suction path 15 via the suction port 14, and injecting the electrolyte solution EL from the liquid reservoir chamber 13 into the outer can 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an injection device and an injection method for injecting an electrolyte into a container in a manufacturing process for a battery cell or the like. [Background technology]

[0002] A battery cell such as a lithium-ion secondary battery contains a positive electrode, a negative electrode, a separator, an electrolyte, etc. in an outer can that forms a container for the battery cell. In the manufacturing process of such a battery cell, it is necessary to efficiently inject the electrolyte. There are two known methods for injecting the electrolyte into the outer can: an open-type injection method and a closed-type injection method. Of these, in the closed-type method, an electrode assembly in which the positive and negative electrodes and the separator are wound or stacked is inserted into the outer can, the opening of the outer can is closed with a lid, the electrolyte is filled through an injection port provided in the lid, and the injection port is then sealed.

[0003] Regarding the injection of electrolyte into the outer can, a method is known in which the inside of the outer can housing the electrode assembly is depressurized and the electrolyte is supplied under reduced pressure. In this method, the electrolyte is sucked into the depressurized outer can as if it were a dropper, and then injected and filled. In this method, the electrolyte is sucked into the outer can maintained at negative pressure, so the injection and filling time can be shortened.

[0004] However, it is difficult to replace all the air in the outer can with the electrolyte by simply reducing the pressure, and fine bubbles still remain in the gaps of the electrode assembly, which are not easy to remove. Specifically, it is possible to make it easier to inject the electrolyte into the outer can by individually reducing the pressure in the syringe that injects the electrolyte into the outer can and the inside of the outer can, and then further reducing the pressure inside the outer can to increase the degree of vacuum. However, in general, a booster pump or the like is used to increase the degree of vacuum, but such pumps have a problem in that the piping is complicated and the injection device becomes large. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. WO14 / 006660 Summary of the Invention [Problem to be solved by the invention]

[0006] One of the objectives of one embodiment of the present disclosure is to provide a liquid injection device and a liquid injection method that have a simplified configuration when injecting liquid under reduced pressure. Another objective of another embodiment is to provide a liquid injection device and a liquid injection method that improve efficiency during liquid injection. Note that the description of these objectives does not preclude the existence of other objectives. Furthermore, it is not necessary for one embodiment of the present disclosure to solve all of these objectives. Furthermore, it is possible to extract other objectives from the description of the specification, drawings, claims, etc. of the present disclosure. Means for solving the objectives and effects of the invention

[0007] A liquid injection method according to a first embodiment of the present disclosure is a method for injecting an electrolyte into an outer can of an electricity storage device, and includes the steps of: inserting a nozzle portion of an injection syringe, the nozzle portion having an injection port for supplying the electrolyte into the inside of the outer can and an suction port connected to a suction path connected to an external pump for depressurizing the outer can, into a cell opening opened in the outer can; reducing the pressure inside the outer can through the suction port and the suction path; supplying the electrolyte to a liquid reservoir chamber airtightly separated from the suction path within the injection syringe; reducing the pressure of the liquid reservoir chamber separately from the inside of the outer can; operating a volume variable mechanism provided on the suction path within the injection syringe to expand the volume of the suction path to further reduce the pressure inside the outer can, which is connected to the suction path via the suction port; and injecting the electrolyte in the liquid reservoir chamber into the outer can. As a result, the pressure inside the outer can, which is already reduced, can be further reduced by operating the volume variable mechanism provided in the injection syringe, which allows the electrolyte to be efficiently injected into the outer can. In particular, the volume variable mechanism incorporated in the injection syringe does not require complex piping as in a booster pump, and allows additional pressure reduction with a simple configuration such as a volume variable mechanism incorporated in the injection syringe. Furthermore, by incorporating the volume variable mechanism in the injection syringe, the effect of efficiently increasing the degree of vacuum can be obtained without the loss caused by the piping path length as in the case of a booster pump.

[0008] A second embodiment of the liquid injection method is the above embodiment, further comprising the step of airtightly closing the liquid injection port so that the liquid reservoir chamber and the inside of the outer can are not in communication with each other prior to the step of reducing the pressure inside the outer can, thereby making it possible to airtightly separate the liquid reservoir chamber and the inside of the outer can and reduce the pressure therebetween separately.

[0009] Further, in the liquid injection method according to a third aspect, in any one of the above aspects, the step of airtightly closing the liquid injection port includes moving a syringe shaft extended within the liquid injection syringe to close a path leading to the liquid injection port with a tip of the syringe shaft, thereby making it possible to close the liquid injection port with a simple configuration of moving the syringe shaft.

[0010] A fourth aspect of the liquid injection method is any of the above aspects, in which the step of supplying the electrolyte to the electrolyte reservoir chamber is performed with the electrolyte reservoir chamber open, thereby enabling the electrolyte to be smoothly supplied to the electrolyte reservoir chamber under atmospheric pressure.

[0011] A fifth aspect of the liquid injection method is any one of the above aspects, wherein the step of supplying the electrolyte to the liquid-reservoir chamber is performed with the rear end of the liquid injection syringe being open in the liquid-reservoir chamber.

[0012] A sixth aspect of the liquid injection method is any one of the above aspects, wherein the step of reducing the pressure in the liquid-reservoir chamber is performed in a state in which the liquid-injection syringe is closed with a syringe cup inserted from a rear end thereof.

[0013] Furthermore, in a seventh aspect of the liquid injection method, in any one of the above aspects, the step of further reducing the pressure inside the outer can is performed by expanding the volume of the suction path with the volume varying mechanism while maintaining the volume of the liquid reservoir chamber at a constant volume with the syringe cup.

[0014] Furthermore, the liquid injection method according to an eighth aspect is any of the above-mentioned aspects, and further includes, following the step of injecting the electrolyte in the liquid reservoir chamber into the outer can, a step of reducing a volume of the liquid reservoir chamber of the injection syringe to pressurize the inside of the outer can.

[0015] A ninth aspect of the liquid injection method is any of the above-mentioned aspects, further comprising, following the step of pressurizing the inside of the outer can, a step of opening the liquid reservoir chamber and the suction path to atmospheric pressure.

[0016] Furthermore, in the liquid injection method according to a tenth aspect, in any one of the above-mentioned aspects, the power storage device is a lithium ion secondary battery.

[0017] Furthermore, the liquid injection device according to the eleventh embodiment is a liquid injection device for injecting an electrolyte into an outer can of an electric storage device, the liquid injection device including a liquid reservoir chamber and a suction path inside, a liquid injection syringe including a nozzle part having a liquid injection port for supplying the electrolyte into the inside of the outer can and a suction port connected at one end to the suction path, a pump connected at the other end to the suction path for depressurizing the outer can, and a tank connected to the liquid reservoir chamber for storing the electrolyte, the liquid injection syringe being provided with a volume variable mechanism on the suction path. With the above configuration, the inside of the outer can in a depressurized state can be further depressurized by operating the volume variable mechanism provided in the liquid injection syringe, thereby making it possible to efficiently inject the electrolyte into the outer can. In particular, the additional depressurization is possible with a simple configuration of a volume variable mechanism incorporated in the liquid injection syringe without requiring complicated piping such as a booster pump. Furthermore, by incorporating a volume-varying mechanism in the injection syringe, loss due to the length of the piping, as occurs with a booster pump, is eliminated, and the degree of vacuum can be increased efficiently.

[0018] A twelfth aspect of the liquid injection device is any of the above aspects, in which the liquid injection syringe includes a movable syringe shaft extending therein. The syringe shaft has a closing portion at its tip for closing a path leading to the liquid injection port, and the closing portion is configured to open and close the path leading to the liquid injection port by moving the syringe shaft. With the above configuration, the liquid injection port can be closed by a simple configuration of moving the syringe shaft, and the liquid reservoir chamber and the interior of the outer can can be air-tightly separated, and the pressure in each of them can be reduced individually.

[0019] A thirteenth aspect of the liquid injection device is any one of the above aspects, in which the liquid injection syringe has an open rear end of the liquid-reservoir chamber, and a syringe cup is slidably inserted into the rear end of the liquid injection syringe. With the above configuration, it is possible to vary the volume of the liquid-reservoir chamber with the syringe cup.

[0020] A fourteenth aspect of the present invention is the liquid injection device according to any one of the above aspects, wherein the power storage device is a lithium ion secondary battery.

[0021] Furthermore, the injection syringe according to the fifteenth embodiment is an injection syringe for an injection device that injects an electrolyte into an outer can of an electric storage device, and includes a liquid reservoir chamber and a suction path inside, a nozzle part that is connected to the liquid reservoir chamber and has an injection port for supplying the electrolyte into the inside of the outer can and a suction port that is connected to the suction path at one end, and a volume variable mechanism is provided on the suction path. With the above configuration, the pressure inside the outer can in a reduced pressure state can be further reduced by operating the volume variable mechanism provided in the injection syringe, thereby making it possible to efficiently inject the electrolyte into the outer can. In particular, the injection syringe does not require complicated piping such as a booster pump, and a simple configuration of a volume variable mechanism incorporated in the injection syringe makes it possible to further reduce the pressure. Furthermore, by incorporating the volume variable mechanism in the injection syringe, the effect of efficiently increasing the degree of vacuum can be obtained without causing loss due to the length of the piping as in the case of a booster pump. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram showing a liquid injection device according to a first embodiment. [Diagram 2] FIG. 11 is a schematic diagram showing a liquid injection device according to a second embodiment. [Diagram 3] FIG. 11 is a schematic diagram showing a liquid injection device according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The present disclosure will be described in more detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper", "lower", and other terms including these terms) are used as necessary, but the use of these terms is for the purpose of facilitating understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present disclosure. In addition, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or members.

[0024] Furthermore, the embodiments shown below are specific examples of the technical ideas of the present disclosure, and do not limit the present disclosure to the following. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended to be illustrative and not to limit the scope of the present disclosure. Furthermore, the contents described in one embodiment can be applied to other embodiments. Furthermore, the sizes and positional relationships of the components shown in the drawings may be exaggerated to clarify the explanation. (Secondary battery 1)

[0025] Hereinafter, a lithium ion secondary battery will be described as an example of an electric storage device to which an electrolyte is injected, and to which the liquid injection device and liquid injection method are applied. The lithium ion secondary battery includes a rectangular outer can 2, an electrode assembly housed in the outer can 2, and an electrolyte housed in the outer can 2. The outer can 2 has a case body in the shape of a square cylinder with a bottom and a plate-shaped lid that closes the opening of the case body. The case body and the lid form the wall of the outer can 2. The lid has a cell opening that penetrates the lid in the plate thickness direction. The secondary battery 1 of this embodiment is a prismatic battery that has a prismatic appearance. Note that the present disclosure is not limited to a prismatic battery as an electric storage device, and can also be applied to a battery with a cylindrical outer can.

[0026] The electrode assembly includes one or more positive electrodes, one or more negative electrodes, and one or more separators. The electrode assembly has a layered structure in which a separator is interposed between a positive electrode and a negative electrode, and the electrodes are stacked in a state of being insulated from each other. The positive electrode and the negative electrode each have a rectangular sheet-shaped current collector, active material layers present on both sides of the current collector, and a current collector tab protruding from a part of one side of the current collector. The current collector tab does not have an active material layer and is composed of the current collector itself. The electrode assembly has a tab group in which one or more current collector tabs are stacked with the same polarity. Here, an example in which multiple sheets are stacked as the current collector has been described, but the current collector may be a single-strand winding current collector in which the electrode is wound in an inverse manner.

[0027] Next, a method for manufacturing the secondary battery 1 will be described. The method for manufacturing the secondary battery 1 includes a liquid injection step of injecting an electrolyte from a cell opening into the outer can 2 housing the electrode assembly, a temporary sealing step of temporarily sealing the cell opening with a temporary sealing member, and an initial charge / discharge step of restraining the outer can 2 with a restraining jig and performing initial charge / discharge. The initial charge / discharge step of this embodiment includes a conditioning step and an aging step. In the conditioning step, initial charging is performed. Depending on the specifications of the secondary battery 1, multiple charge / discharge cycles may be repeated. After the conditioning step, in the aging step, the secondary battery 1 is heated to a predetermined aging temperature in a thermostatic bath and left for a predetermined time. After the initial charge / discharge step, the restraint of the outer can 2 by the restraining jig is released. [Injection device 100]

[0028] 1 shows a liquid injection device 100 for injecting an electrolyte into an exterior can 2 of a secondary battery 1. The liquid injection device 100 shown in this figure includes a liquid injection syringe 10, a pump VP, and a tank TK. (Injection syringe 10)

[0029] The interior of the injection syringe 10 is divided into a liquid reservoir chamber 13 and a suction path 15. The liquid reservoir chamber 13 is a space for temporarily storing the electrolyte solution EL. The liquid reservoir chamber 13 is also connected to a tank TK and receives a supply of the electrolyte solution EL from the tank TK.

[0030] The suction path 15 is a path that is connected at one end (lower part in the figure) to the inside of the outer can 2 via the suction port 14 and at the other end (upper part in the figure) to the pump VP, and reduces the pressure inside the outer can 2 by suctioning with the pump VP.

[0031] The injection syringe 10 is provided with a nozzle portion 11 at its tip (lower portion in the figure). At least a part of its rear end (upper portion in the figure) is open. The nozzle portion 11 is provided with an injection port 12 and a suction port 14. The injection port 12 is connected to a liquid reservoir chamber 13. The electrolyte EL temporarily stored in the liquid reservoir chamber 13 is supplied to the inside of the outer can 2 through the injection port 12. The suction port 14 is connected to a suction path 15, and sucks air from inside the outer can 2 to create a reduced pressure state. In this way, one nozzle portion 11 is connected to a cell opening opened in the lid portion of the outer can 2, the air inside is removed, and the electrolyte EL is injected. The nozzle portion 11 is airtightly connected to the cell opening. With this method, the pressure inside the secondary battery 1 is reduced from the same cell opening as that used for injecting the electrolyte EL, which is advantageous in that the number of openings in the secondary battery 1 can be reduced. In the example of Figure 1, the liquid injection port 12 and the suction port 14 are shown side by side for the purpose of explanation, but any known configuration can be used as appropriate, such as forming one in a circular shape and the other in an annular shape arranged around it. (Pump VP)

[0032] The pump VP is for reducing the pressure inside the liquid injection syringe 10 and the outer can 2. The pump VP is operated to reduce the pressure inside the outer can 2 and the liquid injection syringe 10 by sucking them. The pump VP is connected to the liquid injection syringe 10 via a valve VV. In the example of FIG. 1, the liquid reservoir chamber 13 and the suction path 15 of the liquid injection syringe 10 are connected to the pump VP by separate paths. Each path is provided with a valve VV, and the liquid reservoir chamber 13 and the suction path 15 can be sucked independently to set different vacuum levels. Note that the example of FIG. 1 shows a configuration in which the liquid reservoir chamber 13 and the suction path 15 are reduced in pressure by a common pump VP, but the present disclosure is not limited to this configuration, and the liquid reservoir chamber and the suction path may be connected to separate pumps. (Tank TK)

[0033] The tank TK stores the electrolyte EL to be injected into the outer can 2. The tank TK is connected to the liquid reservoir chamber 13 via a liquid supply pipe. If necessary, a liquid supply pump LP and a valve may be provided on the liquid supply pipe. (Volume variable mechanism 16)

[0034] The injection syringe 10 is provided with a volume variable mechanism 16 on the suction path 15, which can change the volume of the suction path 15. The volume variable mechanism 16 can be formed in a piston or ring shape, and a piston part can be airtightly slid along the suction path 15, or other known configurations can be appropriately used. The pressure inside the outer can 2 can be changed by operating the volume variable mechanism 16. That is, when the volume of the suction path 15 is changed by the volume variable mechanism 16, the pressure inside the outer can 2 communicated with the suction path 15 changes. Specifically, when the volume of the suction path 15 is increased by the volume variable mechanism 16, the pressure inside the suction path 15 decreases, and therefore the pressure inside the outer can 2 communicated with the suction path 15 also decreases. This reduces the pressure inside the outer can 2 below the pressure inside the liquid reservoir chamber 13, making it easier to move the electrolyte EL in the liquid reservoir chamber 13 to the inside of the outer can 2, where the pressure is lower. That is, injection can be performed smoothly.

[0035] The inside of the outer can 2 is depressurized to facilitate injection of the electrolyte solution EL into the inside of the outer can 2. When the internal pressure of the outer can 2 is lower than the internal pressure of the injection syringe 10, the electrolyte solution EL can be easily guided into the inside of the outer can 2 by the pressure difference.

[0036] Conventionally, in order to further reduce the pressure inside the outer can 2, which is already in a reduced pressure state, it has been considered to use a booster pump. However, adding a booster pump would result in complicated piping, higher equipment costs, and greater energy consumption. In addition, losses would occur depending on the length of piping required to add the booster pump.

[0037] In contrast, in the liquid injection device 100 according to this embodiment, the volume variable mechanism 16 is incorporated inside the liquid injection syringe 10, so that no loss in piping occurs. In addition, the volume variable mechanism 16 can be realized with a simple configuration, such as a piston-like configuration, so that additional costs can be kept low. The volume variable mechanism 16 may be provided at an eccentric position inside the liquid injection syringe 10, or may be disposed on the axis of the liquid injection syringe 10, for example, in a circular shape. [Embodiment 2]

[0038] The liquid injection syringe 10 may also include a movable syringe shaft 17 extending therefrom. Such an example is shown in Fig. 2 as a liquid injection device 200 according to embodiment 2. In this figure, the same members as those in embodiment 1 and the like are given the same reference numerals and detailed description thereof will be omitted as appropriate. (Syringe shaft 17)

[0039] The syringe shaft 17 is provided at its tip with a closing part 18 that closes the path leading to the liquid inlet 12. The syringe shaft 17 is configured to be movable so that the closing part 18 can open and close the path leading to the liquid inlet 12. In FIG. 2, when the syringe shaft 17 is raised, the closing part 18 is opened, and when the syringe shaft 17 is lowered, the closing part 18 is closed. In this way, the liquid inlet 12 can be closed by a simple configuration of moving the syringe shaft 17, and the liquid reservoir chamber 13 and the inside of the outer can 2 can be airtightly separated, and the pressure in each of them can be reduced individually. The closing part 18 is formed, for example, in an elastic shape to close the liquid inlet 12 in a liquid-tight manner. Alternatively, a metal provided with a packing or a sealant can be used. In addition, it is not necessary to close the liquid inlet at the tip of the syringe shaft, and a part such as the middle part or the shoulder part can be used to close the liquid inlet. Note that even if the liquid inlet 12 is closed by the closing part 18, the suction port 14 is not closed. As a result, the electrolyte solution EL held in the liquid reservoir chamber 13 is retained, while the suction of air inside the exterior can 2 is not impeded. (Syringe Cup 19)

[0040] The liquid injection syringe 10 has an open rear end of the liquid storage chamber 13. A syringe cup 19 is slidably inserted into the rear end of the liquid injection syringe 10. With this configuration, the volume of the liquid storage chamber 13 can be varied by the syringe cup 19. The syringe cup 19 is configured to move independently of the volume variable mechanism 16. The syringe cup 19 and the volume variable mechanism 16 may be arranged coaxially. The operations of the syringe cup 19 and the volume variable mechanism 16 may be linked. For example, the volume variable mechanism 16 may be moved simultaneously when the syringe cup 19 is inserted, and after the syringe cup 19 is inserted, only the volume variable mechanism 16 is moved while the syringe cup 19 is stopped. [Embodiment 3]

[0041] Furthermore, the present disclosure is not limited to a configuration in which the liquid-reservoir chamber is closed by a sliding syringe cup to adjust the pressure, and it goes without saying that the liquid-reservoir chamber may be closed by other members. For example, as in the liquid injection device 300 according to the third embodiment shown in Fig. 3, a booster BS is provided on the liquid injection syringe to adjust the pressure in the liquid-reservoir chamber.

[0042] In the above-mentioned second and third embodiments, a configuration has been described in which the syringe shaft is extended coaxially with the injection syringe, but the present disclosure is not limited to this configuration, and the syringe shaft may be arranged to be inclined with respect to the extension direction of the injection syringe or to intersect with it. [Injection method]

[0043] A method for injecting the electrolyte solution EL into the exterior can 2 of the electricity storage device will be described below. First, the nozzle 11 of the injection syringe 10 is inserted into a cell opening opened in the lid of the exterior can 2. The nozzle 11 is airtightly connected to the cell opening. In this state, the injection port 12 of the nozzle 11 is closed, and the suction port 14 is opened and communicated with the suction path 15. The suction path 15 is connected to the pump VP.

[0044] Next, the pump VP is operated to reduce the pressure inside the outer can 2 through the suction port 14 and the suction path 15. The degree of vacuum is set according to the volume of the outer can 2, the degree of filling inside, the viscosity of the electrolyte, etc., and is set to, for example, -90 kPa.

[0045] Meanwhile, the electrolyte solution EL is supplied from a tank TK connected to the injection syringe 10 into the liquid reservoir chamber 13 of the injection syringe 10. Because the injection port 12 is closed, the electrolyte solution EL is stored in the liquid reservoir chamber 13. Preferably, the electrolyte solution EL is supplied with the liquid reservoir chamber 13 open. This allows the electrolyte solution EL to be smoothly supplied to the liquid reservoir chamber 13 under atmospheric pressure. For example, injection is performed with the rear end of the injection syringe 10 open.

[0046] Then, with the liquid-reservoir chamber 13 airtightly closed, the liquid-reservoir chamber 13 is depressurized by the pump VP. To airtightly close the liquid-reservoir chamber 13, for example, a syringe cup 19 is inserted from the rear end of the injection syringe 10 to close it. Since the liquid-reservoir chamber 13 is separated from the interior of the outer can 2, the liquid-reservoir chamber 13 is depressurized separately from the interior of the outer can 2. In other words, the liquid-reservoir chamber 13 and the interior of the outer can 2 can be maintained at different pressures or atmospheric pressures.

[0047] In this state, the volume variable mechanism 16 provided on the suction path 15 is operated to expand the volume of the suction path 15, and the inside of the outer can 2 is further depressurized. In general, the electrolyte EL can be injected into the inside of the outer can 2 by providing a pressure difference or air pressure difference between the liquid reservoir chamber 13 and the inside of the outer can 2. The greater the pressure difference, that is, the higher the degree of vacuum inside the outer can 2 is compared to the degree of vacuum in the liquid reservoir chamber 13, the easier it is to inject the electrolyte EL. Therefore, it is important to increase the degree of vacuum inside the outer can 2. However, in a method using a booster pump or the like, the configuration becomes complicated, there is a large loss due to the piping length, and energy efficiency is poor. Therefore, in this embodiment, the volume variable mechanism 16 provided on the suction path 15 is operated in the injection syringe 10 to expand the volume of the suction path 15, and the inside of the outer can 2 communicated with the suction path 15 via the suction port 14 is further depressurized. Then, the electrolyte EL in the liquid reservoir chamber 13 is injected into the outer can 2. This makes it possible to efficiently inject the electrolyte EL into the outer can 2. In particular, the volume variable mechanism 16, which is a simple structure incorporated in the injection syringe 10, enables additional pressure reduction and efficiently increases the degree of vacuum. Also, by expanding only the volume of the suction path 15 with the volume variable mechanism 16 while maintaining the liquid reservoir chamber 13 at a constant volume, it is possible to easily reduce only one pressure and generate a pressure difference.

[0048] After the electrolyte solution EL in the liquid reservoir chamber 13 is injected into the outer can 2, the liquid reservoir chamber 13 is connected to the inside of the outer can 2, so the volume of the liquid reservoir chamber 13 can be reduced to pressurize the inside of the outer can 2. This allows a certain amount of pressure to be applied and preliminary liquid injection to be performed. Finally, the liquid reservoir chamber 13 and the suction path 15 are opened to atmospheric pressure.

[0049] In this way, the electrolyte solution EL can be smoothly injected into the exterior can 2. In addition, the speed at which the electrolyte solution EL permeates the electrode body can be increased, improving the efficiency of the impregnation. [Industrial Applicability]

[0050] The liquid injection device and liquid injection method according to the present disclosure can be applied to injection of liquid into battery cells such as lithium ion secondary batteries, as well as into electricity storage devices such as capacitors, and can also be applied to injection of liquids other than electrolyte.

[0051] Furthermore, according to the liquid injection device and liquid injection method disclosed herein, the energy required to put the power storage device into a vacuum or reduced pressure state can be reduced, and as a result, power consumption can be reduced, and the consumption of fossil fuels required for power generation can be reduced, thereby reducing the environmental impact. As a result, the following 17 goals and 169 targets set out in the international goals SDGs (Sustainable Development Goals) adopted at the United Nations Summit in September 2015 can be achieved: "8. Decent work and economic growth", "8.4 By 2030, improve progressively global resource efficiency in consumption and production and endeavour to decouple economic growth from environmental degradation, in accordance with the 10-year framework of programmes on sustainable consumption and production, with developed countries taking the lead." - This technology contributes to the goals of the Framework Convention on Climate Change (FCCC / COP 9.), such as "9. Build resilient infrastructure, promote inclusive and sustainable development, and promote the development of sustainable development strategies and infrastructure, including through the promotion of sustainable development strategies and the promotion of sustainable development." and "9.4 By 2030, improve infrastructure and improve industry through increased resource efficiency and greater adoption of clean and environmentally friendly technologies and industrial processes. All countries will take action in accordance with their respective capabilities." [Explanation of symbols]

[0052] 100, 200, 300... Liquid injection device 1…Secondary battery 2…Outer can 10...Injection syringe 11…Nozzle section 12…Filling port 13...Liquid storage chamber 14...Suction port 15…Suction path 16...Volume variable mechanism 17…Syringe shaft 18...Closing part 19…Syringe cup EL…Electrolyte VP…Pump TK…Tank VV…Valve LP…Feed pump BS…Booster

Claims

1. A method for injecting an electrolyte into an exterior can of an electricity storage device, comprising the steps of: a step of inserting a nozzle portion of an injection syringe, the nozzle portion having an injection port for supplying the electrolyte into the inside of the outer can and an aspiration port communicating with an aspiration path connected to an external pump for reducing the pressure in the outer can, into a cell opening opened in the outer can; reducing the pressure inside the outer can through the suction port and the suction path; supplying the electrolyte to a liquid reservoir chamber airtightly partitioned from the suction path in the injection syringe; depressurizing the liquid reservoir chamber separately from the interior of the outer can; a step of operating a volume varying mechanism provided on the suction path in the injection syringe to expand a volume of the suction path, thereby further reducing the pressure inside the outer can communicated with the suction path via the suction port; pouring the electrolyte in the electrolyte reservoir chamber into the exterior can; The injection method includes the steps of:

2. The liquid injection method according to claim 1, further comprising: The liquid injection method includes a step of air-tightly closing the liquid injection port so that the liquid reservoir chamber is not in communication with the inside of the outer can prior to the step of reducing the pressure inside the outer can.

3. The liquid injection method according to claim 2, The liquid injection method, wherein the step of air-tightly closing the liquid injection port comprises moving a syringe shaft extended within the liquid injection syringe to close a path leading to the liquid injection port with a tip of the syringe shaft.

4. The liquid injection method according to claim 1, The step of supplying the electrolyte to the electrolyte reservoir chamber is performed with the electrolyte reservoir chamber open.

5. The liquid injection method according to claim 4, The liquid injection method includes a step of supplying the electrolyte to the liquid reservoir chamber, the rear end of the liquid injection syringe being opened in the liquid reservoir chamber.

6. The liquid injection method according to claim 5, The liquid injection method, wherein the step of reducing the pressure in the liquid reservoir chamber is performed in a state in which the liquid injection syringe is closed with a syringe cup inserted from the rear end thereof.

7. The liquid injection method according to claim 6, The liquid injection method, wherein the step of further reducing the pressure inside the outer can is performed by expanding the volume of the suction path with the volume varying mechanism while maintaining the volume of the liquid reservoir chamber at a constant volume with the syringe cup.

8. The liquid injection method according to any one of claims 1 to 7, further comprising: a step of injecting the electrolyte from the electrolyte reservoir chamber into the outer can, followed by a step of reducing a volume of the electrolyte reservoir chamber of the injection syringe to pressurize the inside of the outer can.

9. The liquid injection method according to claim 8, further comprising: The liquid injection method includes a step of releasing the liquid reservoir chamber and the suction path to atmospheric pressure following the step of pressurizing the inside of the outer can.

10. The liquid injection method according to any one of claims 1 to 7, The charging method, wherein the power storage device is a lithium ion secondary battery.

11. A liquid injection device that injects an electrolyte into an exterior can of an electricity storage device, A liquid reservoir chamber and a suction path are defined inside, a liquid injection port communicating with the liquid reservoir chamber for supplying the electrolyte to the inside of the outer can; a suction port connected at one end to the suction path; A liquid injection syringe including a nozzle portion having a pump connected at the other end to the suction path for reducing the pressure of the outer can; a tank communicating with the liquid reservoir chamber and configured to store the electrolyte; Equipped with The injection syringe is an injection device provided with a volume varying mechanism on the suction path.

12. The liquid injection device according to claim 11, The liquid injection syringe has a movable syringe shaft extending therethrough, the syringe shaft has a closing portion at its tip that closes a path leading to the injection port, The liquid injection device is configured so that the path leading to the liquid injection port can be opened and closed at the closing portion by moving the syringe shaft.

13. The liquid injection device according to claim 11, The liquid injection syringe has an open rear end of the liquid reservoir chamber, The liquid injection device has a syringe cup slidably inserted into the rear end of the liquid injection syringe.

14. The liquid injection device according to any one of claims 11 to 13, The liquid injection device, wherein the power storage device is a lithium ion secondary battery.

15. A liquid injection syringe for an injection device that injects an electrolyte into an outer can of an electricity storage device, A liquid reservoir chamber and a suction path are defined inside, a liquid injection port communicating with the liquid reservoir chamber for supplying the electrolyte to the inside of the outer can; a suction port connected at one end to the suction path; A nozzle portion including: The injection syringe further comprises a volume varying mechanism provided on the suction path.

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