Cell container, upper plate, check valve, nozzle, battery cell, and production method therefor

Abstract

[Problem] To disclose technology with which it is possible to prevent the defect of an electrolyte leaking from an injection hole. [Solution] A cell container 11A of a battery cell 10A according to the present embodiment comprises: an injection hole 22 having a check valve mechanism 20A that allows injection of an electrolyte 91 into the cell container 11A and restricts outflow; and a valve opening operation part 27 provided to the check valve mechanism 20A and applying an external force that is not a fluid pressure in order to open the check valve mechanism 20A.

Description

Cell container, upper plate, check valve, nozzle, battery cell, and manufacturing method thereof

[0001] The present disclosure relates to a battery cell and a manufacturing method thereof, a cell container of the battery cell and an upper plate and a check valve which are parts of the cell container, and a nozzle for injecting an electrolyte into the cell container of the battery cell.

[0002] The cell container of a conventional battery cell has a filling hole at the top for filling the electrolyte, and the filling hole is closed after the electrolyte is filled (see, for example, Patent Document 1).

[0003] JP 2013-219027 A (paragraphs

[0019] ,

[0039] , FIG. 3)

[0004] In the conventional cell container described above, there is a problem that the cell container may tip over before the filling hole is closed, causing leakage of the electrolyte from the filling hole. Therefore, this application discloses a technique that can prevent the problem of electrolyte leakage from the filling hole.

[0005] A cell container according to one embodiment of the present disclosure, which has been made to solve the above-described problems, is a cell container for a battery cell, and includes an injection hole for allowing injection of an electrolyte into the cell container, a check valve mechanism that allows the electrolyte to pass into the cell container through the injection hole while restricting the electrolyte from passing out of the cell container through the injection hole, and a valve opening operation unit that is provided on the check valve mechanism and applies an external force other than fluid pressure to open the check valve mechanism.

[0006] 1 is a perspective view of a battery cell of the first embodiment; FIG. 2 is a side cross-sectional view of a battery cell; FIG. 3 is a perspective view of a stack; FIG. 4 is a side cross-sectional view of a portion of the upper plate equipped with a check valve mechanism; FIG. 5 is a side cross-sectional view of a nozzle and a check valve mechanism; FIG. 6 is a side cross-sectional view of a modified upper plate; 11 is a side cross-sectional view of a nozzle and check valve mechanism of a fifth embodiment; FIG. 12 is a side cross-sectional view of a check valve mechanism opened by a nozzle; FIG. 13 is a side cross-sectional view of a nozzle and check valve mechanism of a sixth embodiment; FIG. 14 is a side cross-sectional view of a nozzle and check valve mechanism of a seventh embodiment; FIG. 15 is a side cross-sectional view of a battery cell of an eighth embodiment; FIG. 16 is a side cross-sectional view of a check valve mechanism of a ninth embodiment;

[0007] [First Embodiment] A battery cell 10A according to a first embodiment of the present disclosure will be described with reference to Figures 1 to 7. The battery cell 10A according to this embodiment, shown in its entirety in Figure 1, is, for example, a lithium-ion secondary battery, and includes a laminate 90 having a general structure in which a positive electrode sheet 90A, a negative electrode sheet 90B, and a separator sheet 90C are stacked and wound together as shown in Figure 3, and a cell container 11A that contains an electrolyte 91 together with the laminate 90 as shown in Figure 2. One of the characteristics of the battery cell 10A is that the cell container 11A is provided with a check valve mechanism 20A.

[0008] Although the battery cell 10A of this embodiment is a lithium ion secondary battery, any secondary battery having a check valve mechanism in the cell container may be used.

[0009] As shown in Fig. 1, the cell container 11A has, for example, a rectangular parallelepiped shape that is flat in the horizontal direction. The cell container 11A is manufactured by dividing it into a rectangular parallelepiped container body 12A with an open top and an upper plate 13A that closes a top opening 12K of the container body 12A. The upper plate 13A is formed by assembling a pair of electrodes 15 and multiple components of the check valve mechanism 20A to a rectangular plate body 14 that corresponds to the top opening 12K of the container body 12A. The plate body 14 and the container body 12A are both made of metal, for example, and the upper plate 13A is fixed to the container body 12A by welding or brazing them.

[0010] Although the cell container 11A of this embodiment has a flat rectangular parallelepiped shape, the shape is not limited thereto and may be, for example, a non-flat rectangular parallelepiped, a cylindrical shape, an elliptical cylindrical shape, or other shapes. The container body 12A and the plate body 14 are made of metal (e.g., aluminum, aluminum alloy, stainless steel, iron alloy, etc.), but may also be made of any material, such as resin or ceramic. If both are made of metal, it is preferable that they are the same metal or metals with substantially the same ionization tendency. Furthermore, the cell container 11A of this embodiment is manufactured separately into the container body 12A and the upper plate 13A. However, for example, one side of the plate body 14 may be continuous with one opening edge of the container body 12A, so that the container body 12A and the upper plate 13A can be manufactured as a single unit. Furthermore, when the container body 12A and the upper plate 13A are manufactured separately, the method of fixing them is not limited to welding or brazing, but may be, for example, a structure in which the two are fixed by caulking, adhesive, screwing, etc. Furthermore, the term "fixing" in the following description may also be any method such as welding, brazing, caulking, adhesive, screwing, etc.

[0011] As shown in Fig. 2, the pair of electrodes 15 described above includes, for example, a rectangular support plate 15A, a support post 15B extending upward from the support plate 15A, and a connection portion 15C extending downward from the support plate 15A. The support plate 15A of the pair of electrodes 15 is fixed to both longitudinal ends of the plate body 14 via an insulating material (not shown), thereby blocking a pair of through holes 15D from above. The connection portion 15C of each electrode 15 extends downward from the plate body 14. A connection piece 90A1 (see Fig. 3) extending from the positive electrode sheet 90A is fixed to the connection portion 15C of one electrode 15, and a connection piece 90B1 (see Fig. 3) extending from the negative electrode sheet 90B is fixed to the connection portion 15C of the other electrode 15.

[0012] 1, for example, a relief valve mechanism 16 is provided in the center of the upper plate 13A. The relief valve mechanism 16 has a structure in which an open port 16A formed in the plate body 14 is closed by a break sheet 16B that is superimposed on and fixed to the lower surface of the plate body 14. The break sheet 16B has a strength that allows it to break when the pressure inside the cell container 11A exceeds a predetermined limit pressure.

[0013] Although the relief valve mechanism 16 of this embodiment breaks the breakable sheet 16B to release pressure, it may alternatively be configured to include, for example, a valve element that is supported so as to be linearly or rotatably movable and that can close the opening 16A from the outside, and a spring member that biases the valve element in the closing direction, so that when the pressure inside the cell container 11A exceeds a predetermined limit pressure, the valve element opens against the biasing force of the spring member, thereby releasing pressure. Alternatively, a relief valve may be manufactured as a unit separate from the plate main body 14, and the relief valve may be assembled to the plate main body 14 to form the relief valve mechanism 16. Although the cell container 11A of this embodiment includes the relief valve mechanism 16, the cell container 11A may also be configured without the relief valve mechanism 16.

[0014] 1, the check valve mechanism 20A is disposed on the upper plate 13A, for example, between the relief valve mechanism 16 and one of the electrodes 15. As shown in Fig. 4, the check valve mechanism 20A includes a support cylinder portion 21 provided on the plate body 14, a movable body 23 supported by the support cylinder portion 21 so as to be linearly movable, and a spring member 26 that biases the movable body 23 in one of the linear directions.

[0015] Support tube portion 21 is, for example, a cylindrical body formed integrally with plate body 14 and protruding downward from plate body 14, with its interior forming injection hole 22 that penetrates plate body 14 from top to bottom. Support tube portion 21 also has an annular protrusion 21T formed on the tip surface thereof, with its inner edge (i.e., the opening edge of injection hole 22) protruding along its entire length. Injection hole 22 expands in a stepped manner upward, with small diameter portion 22A, medium diameter portion 22B, and large diameter portion 22C extending from the bottom to the top. A tapered chamfered surface 22D1 is formed at the corner where the inner surface of injection hole 22 intersects with the tip surface of annular protrusion 21T, and an arc-shaped chamfered surface 22D2 is formed at the corner where the inner surface of injection hole 22 intersects with the top surface of plate body 14.

[0016] In this embodiment, the support tube portion 21 protrudes only downward from the plate body 14. However, it may protrude only upward from the plate body 14, or may protrude both upward and downward. Furthermore, while the support tube portion 21 in this embodiment has a circular cross section, it may also have an elliptical or oblong cross section. Furthermore, while the support tube portion 21 in this embodiment is formed integrally with the plate body 14, as shown in FIG. 6 , a support tube portion 21B separate from the plate body 14 may be provided, and the support tube portion 21B may be fixed to the plate body 14. In this case, the check valve mechanism 20B, which includes the support tube portion 21B and is a separate unit from the plate body 14, also serves as a "check valve" as a stand-alone component. The check valve in FIG. 6 has, for example, a flange 21F at the upper end of the support tube portion 21B and a threaded portion 21N on the upper outer circumferential surface of the support tube portion 21B. The screw portion 21N is screwed into the screw hole 14N formed in the plate body 14, and the O-ring 21R is sandwiched between the plate body 14 and the flange 21F, and the plate body 14 is fixed to the plate body 14. As described above, the fixing may be by any method, such as welding or caulking.

[0017] As shown in Figure 4, the movable body 23 has a structure in which a flange portion 23B projects from the lower end of a shaft portion 23A that is loosely fitted into the small-diameter portion 22A of the injection hole 22. A seal member, such as a disk-shaped packing 24, is placed on the upper surface of the flange portion 23B. The shaft portion 23A is inserted into the injection hole 22 from below, with the packing 24 facing the tip surface of the support tube portion 21 (more specifically, the annular protrusion 21T). The outer diameter of the shaft portion 23A is smaller than the inner diameter of the small-diameter portion 22A of the support tube portion 21, and a gap is provided between the outer surface of the shaft portion 23A and the inner surface of the support tube portion 21. When the movable body 23 is positioned in the open position where the packing 24 is away from the annular protrusion 21T, the check valve mechanism 20A is opened, opening the injection hole 22 and allowing liquid and gas to pass through the injection hole 22 (see Figure 5), and when the movable body 23 is positioned in the closed position where the packing 24 abuts against the annular protrusion 21T, the check valve mechanism 20A is closed, blocking the injection hole 22 and prohibiting liquid and gas from passing through the injection hole 22.

[0018] The movable body 23 in this embodiment may have any structure in which the flange portion 23B projects from the shaft portion 23A, and may have, for example, the flange portion 23B located midway along the axial direction of the shaft portion 23A, or the flange portion 23B may have a disk structure with a central hole into which the shaft portion 23A is press-fit, or the flange portion 23B and the shaft portion 23A may be integrally formed. Also, although the gasket 24 is shown as the sealing member, it is not limited to a gasket and may also be an O-ring.

[0019] The upper end of the shaft portion 23A is a small-diameter tip portion 23A1, which is stepped and reduced in diameter relative to the entire shaft portion 23A. A locking ring 25 is fixed to the small-diameter tip portion 23A1 at a midpoint in the axial direction. The locking ring 25 is a general-purpose part commonly known as a "clip ring," "lock washer," or "flower washer." The locking ring 25 has a structure in which multiple protrusions 25B extend inward from the annular portion 25A. The locking ring 25 is press-fitted into the small-diameter tip portion 23A1 to lock it at a midpoint in the axial direction. The locking ring 25 has an outer diameter that is larger than the inner diameter of the medium-diameter portion 22B but smaller than the inner diameter of the large-diameter portion 22C. The locking ring 25 moves up and down within the large-diameter portion 22C as the movable body 23 moves linearly. Furthermore, when the movable body 23 is positioned in the closed position, the upper end surface of the shaft portion 23A is located slightly below the upper surface (outer surface) of the plate main body 14, so that the shaft portion 23A does not protrude outward from the injection hole 22.

[0020] The spring member 26 is, for example, a compression coil spring, and is assembled in a tensioned state between the locking ring 25 and a step surface 22E between the small diameter portion 22A and the medium diameter portion 22B of the casting hole 22, thereby biasing the movable body 23 toward the closed position. As a result, in the normal state where no force is being applied to the movable body 23 from outside the cell container 11A, the check valve mechanism 20A is in a closed state, and when a force of a magnitude sufficient to counter the biasing force of the spring member 26 is applied to the movable body 23 from outside the cell container 11A, the check valve mechanism 20A is in an open state. The upper end of the shaft portion 23A forms a valve opening operation portion 27 for applying a force other than fluid pressure to the movable body 23 from outside the cell container 11A.

[0021] In this embodiment, the spring member 26 is prevented from coming off by the locking ring 25, but any structure that can hold the spring member 26 in a tensioned state may be used. For example, instead of the locking ring 25, a structure in which a washer is fixed to the shaft portion 23A by press-fitting, caulking, or screwing may be used. Also, instead of a structure in which a separate washer is provided on the shaft portion 23A, a structure in which a washer is provided integrally with the shaft portion 23A may be used. When a washer that prevents the spring member 26 from coming off is integrally formed on the shaft portion 23A, the spring member 26 can be made a barrel-shaped or conical coil spring, which makes it easier to assemble the spring member 26 to the shaft portion 23A.

[0022] Of the components included in the check valve mechanism 20A, such as the support cylinder 21, the movable body 23, the packing 24, the locking ring 25, and the spring member 26, all except the packing 24 are made of metal, such as aluminum, aluminum alloy, stainless steel, iron alloy, etc. Here, if the components other than the packing 24 that are in contact with each other are all made of metal, they must all be made of the same metal, or all of them must have substantially the same ionization tendency, or the conductivity of at least one of the components at 20°C must be 1.74 x 10 ６ It is preferable that the resistance to moisture is 0.5 S / m or less or 3% IACS or less. In this embodiment, all components except for the packing 24 are made of stainless steel. The packing 24E may be made of any material as long as it has elasticity, such as elastomer (including rubber and thermoplastic elastomer), soft resin, etc.

[0023] In addition, when components other than the packing 24 that come into contact with each other are made of dissimilar metals, at least one of the metal components may be coated with an insulating material such as resin to prevent corrosion due to contact between the dissimilar metals. Furthermore, instead of being made of metal, components other than the packing 24 may be made of non-metallic materials such as resin or ceramic. When components other than the packing 24 are made of resin, ceramic, or the like, all of the components that make up the check valve mechanism 20A are made of non-conductive materials.

[0024] This completes the description of the structure of the battery cell 10A of this embodiment. Figure 5 shows the nozzle 50A used in manufacturing the battery cell 10A. This nozzle 50A is used to inject the electrolyte 91 (see Figure 2) into the cell container 11A, and is connected to a tank that stores the electrolyte 91 via a hose and pump (not shown).

[0025] The tip of the nozzle 50A is provided with an opening edge abutment portion 51, which is a circular, flat surface. The inside of this opening edge abutment portion 51 forms a tip opening 50K, which is the discharge port of the flow path 50R inside the nozzle 50A. The diameter of the tip opening 50K is approximately the same as the diameter of the injection hole 22 of the battery cell 10A on the outer surface side of the battery cell 10A. The flow path 50R extends from the tip of the nozzle 50A to a position near the tip, with approximately the same inner diameter as the tip opening 50K. A partition wall 53 is provided inside the nozzle 50A near the tip, facing the tip opening 50K from inside the nozzle 50A. Multiple small flow paths 50S included in the flow path 50R pass through the center of the partition wall 53.

[0026] The nozzle 50A is provided with a rod-shaped valve opening 52 that extends from the center of the surface of the partition wall 53 facing the tip opening 50K to a position forward of the opening edge abutment 51. When the opening edge abutment 51 abuts against the opening edge of the injection hole 22 on the outer surface of the battery cell 10A, the valve opening 52 presses against the valve opening operation part 27 of the check valve mechanism 20A, holding the check valve mechanism 20A in an open state.

[0027] Next, a method for manufacturing the battery cell 10A of this embodiment will be described. To manufacture the battery cell 10A, for example, the above-described container body 12A, upper plate 13A, and stack 90 are prepared separately. Then, in an assembly process, the connection pieces 90A1, 90B1 of the stack 90 are connected to the connection portions 15C of the pair of electrodes 15 of the upper plate 13A, and the stack 90 is housed in the container body 12A and assembled with the upper plate 13A closing the top opening 12K of the container body 12A. Then, the plate body 14 of the upper plate 13A is welded or brazed to the edge of the top opening 12K of the container body 12A. This completes the assembly process.

[0028] Next, the electrolyte injection process is performed. In preparation for this, the multiple battery cells 10A that have completed the assembly process are fixed to a jig, such as a dolly (not shown), and positioned. The dolly is then positioned in front of an electrolyte injection robot (not shown) that holds the nozzle 50A described above. Then, for example, a program that has been pre-taught to the electrolyte injection robot is executed, and the nozzle 50A is sequentially connected to the injection holes 22 of the multiple battery cells 10A, and a predetermined amount of electrolyte 91 is injected into each battery cell 10A (see FIG. 5 ).

[0029] Here, since it takes time for the electrolyte solution 91 to penetrate between the positive electrode sheet 90A, the negative electrode sheet 90B, and the separator sheet 90C in each battery cell 10A, the cycle operation of sequentially injecting the electrolyte solution 91 into multiple battery cells 10A is repeated over multiple cycles, and the electrolyte solution 91 is injected into each battery cell 10A in multiple batches. Furthermore, the nozzle 50A is connected to the injection hole 22 of each battery cell 10A by pressing the opening edge abutment portion 51 of the nozzle 50A against the opening edge of the injection hole 22 on the outer surface of the battery cell 10A. At this time, the valve opening portion 52 of the nozzle 50A presses the valve opening operation portion 27 of the check valve mechanism 20A, maintaining the check valve mechanism 20A in an open state. This reduces fluid resistance due to the check valve mechanism 20A, allowing for smooth injection of the electrolyte solution 91. Furthermore, if the injection method is such that the check valve mechanism 20A opens due to the fluid pressure of the electrolyte 91 without pressing the valve opening operation part 27, the so-called hunting phenomenon, in which the check valve mechanism 20A repeatedly opens and closes, may occur. However, according to the injection method of this embodiment, the occurrence of the hunting phenomenon is prevented.

[0030] Furthermore, after the electrolyte 91 has been injected, the filling hole 22 of the battery cell 10A, which is waiting for the next injection, is closed by the check valve mechanism 20A when the nozzle 50A is removed, preventing contact between the electrolyte 91 in the cell container 11A and the outside air. This eliminates the need for strict air management in the factory where the electrolyte injection process is carried out. Furthermore, even if the battery cell 10A falls over due to an unexpected collision, the filling hole 22 is closed by the check valve mechanism 20A, preventing problems such as the electrolyte 91 leaking from the filling hole 22 of the battery cell 10A.

[0031] After the electrolyte injection process is completed, the initial charging process is performed. For this purpose, the cart is moved to, for example, a charging device (not shown). Then, for example, pairs of charging electrodes provided on the charging device are connected to pairs of electrodes 15 of the multiple battery cells 10A on the cart, and a voltage is applied between the pair of electrodes 15 of each battery cell 10A for a predetermined period of time.

[0032] After the initial charging process is completed, the gas exhausting process is performed. To this end, the cart described above is positioned in front of the exhaust robot (not shown). A tool (not shown) equipped with multiple pins arranged side by side is attached to the tip of the gas exhausting robot. For example, when a program previously taught to the gas exhausting robot is executed, the gas exhausting robot performs a gas exhausting process by pressing the multiple pins against the valve opening operation parts 27 of the check valve mechanisms 20A of the multiple battery cells 10A and then immediately releasing them. This momentarily opens the check valve mechanisms 20A of the multiple battery cells 10A, releasing the gas generated inside the battery cells 11A during the initial charging process and bringing the pressure inside the battery cells 11A close to atmospheric pressure. This completes the gas exhausting process and the manufacture of the battery cells 10A.

[0033] The battery cell 10A and its manufacturing method of this embodiment provide the following advantageous effects. That is, the check valve mechanism 20A is provided in the fill hole 22 of the cell container 11A of the battery cell 10A of this embodiment, preventing the electrolyte 91 from leaking from the fill hole 22. Furthermore, the check valve mechanism 20A closes the fill hole 22 of the battery cell 10A while it is waiting after the electrolyte 91 has been filled, preventing contact between the electrolyte 91 in the cell container 11A and the outside air. This eliminates the need for strict air management in the factory where the electrolyte filling process is carried out.

[0034] Furthermore, since the cell container 11A is manufactured separately into the container body 12A and the upper plate 13A having the check valve mechanism 20A, the assembly work of the check valve mechanism 20A can be easily performed, improving production efficiency.

[0035] Furthermore, in the manufacturing method of the battery cell 10A of this embodiment, when the electrolyte 91 is injected into the battery cell 10A, a nozzle 50A equipped with a valve opening portion 52 is used, and the valve opening portion 52 presses the valve opening operation portion 27 of the check valve mechanism 20A, thereby holding the check valve mechanism 20A in an open state. This reduces fluid resistance when the electrolyte 91 is injected, enabling smooth injection and preventing the hunting phenomenon in which the check valve mechanism 20A repeatedly opens and closes.

[0036] Furthermore, in the manufacturing method of the battery cell 10A of this embodiment, after the initial charging step, a gas exhausting step is performed to exhaust gas generated within the battery cell 10A during the initial charging step, thereby eliminating the following problem: In conventional battery cell manufacturing methods, initial charging is performed after injecting electrolyte into the cell container and sealing the injection hole, which causes a problem in that the inside of the cell container is pressurized by gas generated during initial charging even before the battery is used, making the cell container more susceptible to deformation and deterioration. In contrast, the battery cell 10A of this embodiment is equipped with a check valve mechanism 20A, which makes it possible to perform a gas exhausting step to exhaust gas within the battery cell 10A after initial charging, and performing this gas exhausting step eliminates the above problem.

[0037] Furthermore, providing the battery cell 10A with the check valve mechanism 20A enables a manufacturing method in which, for example, after the electrolyte solution 91 is injected into the cell container 11A in the electrolyte solution injection step described above, compressed gas is injected into the cell container 11A to pressurize the inside of the battery cell 10A. This increases the rate at which the electrolyte solution 91 permeates between the positive electrode sheet 90A, negative electrode sheet 90B, and separator sheet 90C, improving production efficiency.

[0038] Furthermore, the check valve mechanism 20A of the battery cell 10A is provided with a valve opening operation unit 27 for applying an external force other than fluid pressure to open the check valve mechanism 20A, which makes it possible to intentionally release the electrolyte 91 and gas inside the cell container 11A to the outside, thereby increasing the degree of freedom in the manufacturing method of the battery cell 10A.

[0039] In the manufacturing method of this embodiment, the check valve mechanism 20A is opened by pressing the valve opening portion 52 of the nozzle 50A against the valve opening operation portion 27 when the electrolyte 91 is injected, but it is also possible to use a nozzle that does not have the valve opening portion 52 and open the check valve mechanism 20A using only the fluid pressure of the electrolyte 91 during injection, without pressing the valve opening operation portion 27. Also, although a robot was used to inject the electrolyte 91 into the battery cell 10A and to vent gas from the battery cell 10A, these tasks may be performed by a worker.

[0040] Furthermore, after the above-described gas exhaust process is completed, in order to reliably prevent water and other foreign matter from entering battery cell 10A through injection hole 22, a blocking member 28 may be superimposed and fixed to the outer surface of plate body 14 so as to block injection hole 22, as shown in Fig. 7, or a cap-type blocking member (not shown) may be fitted or screwed onto injection hole 22 to block injection hole 22. Note that in the second to fourth and ninth embodiments described below, injection hole 22 may also be blocked by blocking member 28 in a similar manner.

[0041] If the blocking member 28 is configured to be detachable from the filling hole 22, or if the blocking member 28 is not provided, for example, when the electrolyte 91 in the battery cell 10A deteriorates, the battery cell 10A can be easily recycled by opening the check valve mechanism 20A and filling it with an activator. The same applies to the second to ninth embodiments described below.

[0042] Second Embodiment The present embodiment shown in FIG. 8 differs from the first embodiment only in the structure of the check valve mechanism 20C. The check valve mechanism 20C includes a support tube 21C protruding downward from the plate body 14, a movable body 23C supported by the support tube 21C for linear movement, and a spring member 26 that biases the movable body 23C in one linear movement direction. The support tube 21C is, for example, a cylindrical body protruding downward from the plate body 14, with a bottom wall at the lower end and a through-hole 22G at the center of the bottom wall. The inside of the support tube 21C and the through-hole 22G in the bottom wall of the support tube 21C form an injection hole 22 that penetrates the plate body 14. A disc wall 22F protrudes inward from the upper opening edge of the injection hole 22, and a gasket 24C is superimposed and fixed on the underside of the disc wall 22F.

[0043] The movable body 23C has a shape in which a shaft portion 23A extends downward from the center of the lower surface of the flange portion 23B. The outer diameter of the flange portion 23B is larger than the inner opening diameter of the disc wall 22F and smaller than the inner diameter of the support cylinder portion 21C. The outer diameter of the shaft portion 23A is smaller than the inner diameter of the through-hole 22G. The shaft portion 23A passes through the through-hole 22G, and the flange portion 23B is housed within the support cylinder portion 21C. The central portion of the upper surface of the flange portion 23B forms a valve opening operation portion 27.

[0044] The check valve mechanism 20C of this embodiment also provides the same effects as those of the first embodiment. Note that the movable body 23C may have a structure in which the shaft portion 23A is eliminated.

[0045] Third Embodiment The present embodiment shown in FIG. 9 differs from the first and second embodiments only in the structure of the check valve mechanism 20D, in that the movable body 30 is rotatably supported. Specifically, the check valve mechanism 20D of this embodiment includes an annular protrusion 14K that protrudes from the edge of the opening of the casting hole 22 on the underside of the plate body 14, a packing 24D that is fixed to cover the annular protrusion 14K from below, a rotation support portion 14D that protrudes downward from a position on the plate body 14 near the annular protrusion 14K, a movable body 30 that is rotatably supported on the lower end of the rotation support portion 14D and positioned opposite the packing 24D, and a spring member 26D, which is a torsion coil spring, that biases the movable body 30 against the packing 24D. The movable body 30 has a circular shape corresponding to the opening on the lower end of the casting hole 22 and has an annular protrusion 30T that bites into the packing 24D. The center of the upper surface of the movable body 30 serves as a valve opening operation portion 27. The check valve mechanism 20D of this embodiment also provides the same effects as those of the first embodiment.

[0046] 10 differs from the first to third embodiments only in the structure of a check valve mechanism 20E. The check valve mechanism 20E has a structure including a check valve 20Z that is commonly used as a "valve core" for a tire valve, for example.

[0047] Specifically, check valve mechanism 20E includes, for example, valve sleeve 21E that passes through through-hole 14E of plate body 14 and is fixed thereto, protruding vertically from plate body 14, with injection hole 22 being formed inside valve sleeve 21E. Injection hole 22 is narrowest near the bottom end and gradually decreases in diameter from the top end toward the bottom. Threaded portions 22N, 22M are formed on the upper inner and outer surfaces of injection hole 22.

[0048] The check valve 20Z includes a valve stem 33, a movable body 31, a spring member 32, a sealing ring 24F, and other components. The valve stem 33 comprises a cylindrical stem body 34 extending vertically, with a head portion 35 rotatably connected to the upper end thereof. The stem body 34 has an outer diameter that decreases in a stepped manner downward, and the sealing ring 24F is fitted to the outer peripheral surface of the stem body 34 at a vertical midpoint. The head portion 35 has a structure in which a bridge portion 35B is bridged over the upper surface of a ring portion 35A concentric with the stem body 34, with a through-hole 35C extending vertically through the center of the bridge portion 35B. A threaded portion 35N is formed on the outer peripheral surface of the ring portion 35A.

[0049] The movable body 31 has a structure in which a flange portion 31B is fixed to the lower end of a shaft portion 31A extending in the vertical direction, and a packing 24E is held by the flange portion 31B. The shaft portion 31A is inserted into the valve stem 33 from below and also passed through the through-hole 35C. A spring member 32, which is a compression coil spring, is inserted into the portion of the shaft portion 31A that protrudes above the head portion 35, and a crimped protrusion 31T is formed at the upper end of the shaft portion 31A in a compressed and deformed state. The spring member 32 is tensioned between the crimped protrusion 31T and the head portion 35. As a result, the resilient force of the spring member 32 presses the packing 24E against the lower end opening of the valve stem 33. When the valve opening operation portion 27 at the upper end of the shaft portion 31A is pressed, the packing 24E separates from the lower end opening of the valve stem 33, allowing fluid to pass through the valve stem 33.

[0050] Check valve 20Z is inserted into injection hole 22 from above and is fixed within injection hole 22 by threaded engagement between threaded portion 22N and threaded portion 35N. Closure member 28E is detachably attached to the top of valve sleeve 21E. Specifically, closure member 28E has a cylindrical shape with a bottom at the top end and is provided with threaded portion 28N on its inner surface. Threaded portion 28N of closure member 28E is threadedly engaged with threaded portion 22M of valve sleeve 21E, thereby fixing closure member 28E to valve sleeve 21E.

[0051] Fifth Embodiment This embodiment, shown in Figures 11 and 12, differs from the first embodiment in the structure of a nozzle 50B. This nozzle 50B includes a nozzle body 53B, which is configured by excluding the portion distal to partition wall 53 of nozzle 50A (see Figure 5) of the first embodiment, and a bellows-shaped extension pipe 54 fitted and fixed to the outside of the distal end of nozzle body 53B. In a natural, unforced state, extension pipe 54 extends to a position beyond valve opening 52, and its distal end surface forms opening edge abutment 51. When nozzle 50B is connected to casting hole 22, nozzle 50B is lowered with valve opening 52 positioned coaxially with casting hole 22 in check valve mechanism 20A. 11, opening edge abutment portion 51 abuts against the opening edge of injection hole 22 on the outer surface of plate body 14, connecting flow path 50R inside nozzle 50B with injection hole 22, and then, as shown in Fig. 12, valve opening portion 52 abuts against valve opening operation portion 27 of check valve mechanism 20A, changing check valve mechanism 20A from the closed state to the open state. This more reliably prevents outside air from entering battery cell 10A.

[0052] Sixth Embodiment This embodiment, shown in FIG. 13 , differs from the first embodiment in the structure of a nozzle 50C. This nozzle 50C has a connecting tube portion 55 protruding from the inner edge of the tip surface of the nozzle 50A (see FIG. 5 ) of the first embodiment. When the nozzle 50C is positioned coaxially with the casting hole 22 and moved toward it, the tip of the connecting tube portion 55 engages with the casting hole 22, and the valve opening portion 52 abuts against the valve opening operation portion 27 of the check valve mechanism 20A. Further, as the connecting tube portion 55 and the casting hole 22 are further engaged, the valve opening operation portion 27 is pressed by the valve opening portion 52 of the nozzle 50C, switching the check valve mechanism 20A from the closed state to the open state. This more reliably prevents outside air from entering the battery cell 10A. In this embodiment, the outer surface of the connecting tube portion 55 functions as the opening edge abutment portion 51.

[0053] Seventh Embodiment This embodiment, shown in FIG. 14 , differs from the first embodiment in the structure of a nozzle 50D and the structure of the outer surface of the plate body 14. The nozzle 50D of this embodiment has an L-shaped distal end, and an air cylinder 56 is fixed to the outer surface of an opening-facing wall 50T, a wall portion facing the distal opening 50K. A linear-acting rod 56R provided on the air cylinder 56 penetrates the opening-facing wall 50T and extends toward the distal opening 50K. A support protrusion 50S protrudes from the inner surface of the opening-facing wall 50T, supporting the linear-acting rod 56R so that it can move linearly. By selectively supplying compressed air to the distal end and proximal end of the air cylinder 56, the linear-acting rod 56R moves between a forward position where it protrudes from the distal opening 50K and a retracted position where it retracts toward the opening-facing wall 50T.

[0054] An annular projection 14J projects from the outer surface of plate body 14 and fits onto the outside of nozzle 50D with the center of tip opening 50K of nozzle 50D aligned with the center of injection hole 22.

[0055] The nozzle 50D of this embodiment is fitted to the annular protrusion 14J with the linear acting rod 56R in the retracted position. When the supply of compressed air to the air cylinder 56 is switched, the linear acting rod 56R moves from the rear end position to the forward position, and the linear acting rod 56R presses the valve opening operation unit 27, switching the check valve mechanism 20A from the closed state to the open state. That is, in this embodiment, the linear acting rod 56R functions as the "valve opening unit."

[0056] Eighth Embodiment A battery cell 10B of this embodiment shown in Figure 15 is equipped with check valve mechanisms 20A on the top, side, and bottom surfaces. In addition, recesses 90G are formed in the stack 90 to prevent the check valve mechanisms 20A on the side and bottom surfaces from interfering with the stack 90. ​​With this battery cell 10B, electrolyte 91 can be injected not only from the top surface of the battery cell 10B but also from the side and bottom surfaces, allowing the electrolyte 91 to efficiently penetrate between the positive electrode sheet 90A, negative electrode sheet 90B, and separator sheet 90C that are arranged near the side and bottom surfaces.

[0057] In this embodiment, the check valve mechanism 20A is arranged on three surfaces of the battery cell 10B: the top surface, the side surface, and the bottom surface. However, the check valve mechanism 20A may be arranged on any of a plurality of surfaces of the battery cell 10B, or on any one surface.

[0058] 16 and 17 differ from the first embodiment in the structure of a check valve mechanism 20F and a nozzle 50F. As shown in Fig. 16, this check valve mechanism 20F includes a support cylinder portion 40 that is fixed to and overlaps the inner surface of the plate body 14, a movable body 60 that is housed in the support cylinder portion 40 so as to be able to move linearly, and a spring member 26 that biases the movable body 60 to one side in the linear movement direction.

[0059] The support tube portion 40 is, for example, a cylindrical body with an open upper end, and is provided with a flange portion 41 that protrudes laterally at the upper end, and a reduced-diameter portion 42 at the lower end that is reduced in diameter compared to the upper end. The support tube portion 40 also has a through-hole 43 that penetrates the center of the bottom wall, and multiple through-holes 44 that are formed by cutting out the side wall including the flange portion 41 at multiple positions in the circumferential direction. The support tube portion 40 is fitted inside an annular tube-shaped holding portion 14A that protrudes from the inner surface of the plate body 14, and is fixed to the plate body 14 by crimping the tip of the tube-shaped holding portion 14A.

[0060] The movable body 60 includes, from top to bottom, a medium-diameter section 61, a small-diameter section 62, a valve element 63, and a cylindrical section 64. The medium-diameter section 61 and the small-diameter section 62 are large enough to fit through the injection hole 22 that penetrates the plate body 14, and an O-ring 24F is engaged with the small-diameter section 62 as a sealing member. Tapered chamfered surfaces 22J and 22K are formed at the upper and lower ends of the injection hole 22, with the lower chamfered surface 22K having a greater slope than the upper chamfered surface 22J. The outer surface of the plate body 14 is formed with a recessed section 14B that surrounds the injection hole 22, and an annular protrusion 14C that protrudes outward is formed at the opening edge of the injection hole 22. The upper end surface of the annular protrusion 14C is located at approximately the same height as the outer surface of the plate body 14.

[0061] Valve body 63 is disk-shaped with an outer diameter larger than medium-diameter portion 61 and tubular portion 64. The outer diameter is larger than the inner diameter of injection hole 22 (more specifically, the inner diameter of the lower end of chamfered surface 22K) and smaller than the inner diameter of the upper end of support tubular portion 40, enabling it to close injection hole 22. Tubular portion 64 is, for example, annular, and its inner diameter is slightly smaller than through-hole 43 (see FIG. 17 ).

[0062] The spring member 26 is assembled in a tensioned state between the valve body 63 and the bottom wall of the support cylinder 40 within the support cylinder 40, and urges the movable body 60 toward the closed position. The upper end of the medium diameter portion 61 forms the valve opening operation portion 27, and in the closed position, for example, the valve opening operation portion 27 is disposed approximately flush with the upper end of the annular protrusion 14C. The reduced diameter portion 42 of the support cylinder 40 is slightly larger than the outer diameter of the spring member 26, and restricts movement of the spring member 26 in a direction intersecting the axial direction.

[0063] In this embodiment, the plate body 14 is made of metal as in the first embodiment, whereas the support cylinder portion 40 and the movable body 60 that come into contact with the plate body 14 are made of, for example, resin or ceramic. Also, in the check valve mechanism 20F, only the spring member 26 is made of, for example, metal (e.g., stainless steel, iron alloy, etc.), and the spring member 26 is not in direct contact with the plate body 14. Note that the O-ring 24F may be made of any material as long as it has elasticity, and may be made of, for example, elastomer (including rubber, thermoplastic elastomer, etc.), soft resin, etc.

[0064] As shown in FIG. 17 , nozzle 50F of this embodiment has a cylindrically protruding valve opening 52 at its tip, with multiple through-holes 52H formed at the tip of valve opening 52. Furthermore, nozzle 50F has an elastic opening abutment 51 fitted to valve opening 52. When nozzle 50F is positioned coaxially with casting hole 22 and moved closer, valve opening 52 abuts against valve opening operation 27 of check valve mechanism 20F, and opening edge abutment 51 abuts against annular protrusion 14C, sealing the gap between valve opening 52 and annular protrusion 14C. Furthermore, when the engagement between valve opening 52 and casting hole 22 is deepened, valve opening operation 27 is pressed by valve opening 52 of nozzle 50F, switching check valve mechanism 20F from a closed state to an open state. This prevents outside air from entering battery cell 10A. The opening contact portion 51 is made of, for example, elastomer (including rubber, thermoplastic elastomer, etc.), soft resin, or the like.

[0065] The check valve mechanism 20F of this embodiment achieves the same effects as those of the first embodiment. In addition, because only the valve opening operation part 27 of the check valve mechanism 20F is configured to face the outside through the filling hole 22, adhesion of the electrolyte 91 to the outside air side of the cell container 11A is suppressed, thereby suppressing corrosion of the cell container 11A. Furthermore, even if the electrolyte 91 adheres to the valve opening operation part 27 and its surroundings, it can be easily removed. Furthermore, the annular protrusion 14C of the cell container 11A can prevent the electrolyte 91 from leaking from the filling hole 22.

[0066] Furthermore, in the check valve mechanism 20F of this embodiment, the support tube portion 40 and the movable body 60, which come into contact with the stainless steel spring member 26, are made of resin, so there is no contact between the metals, improving the durability of the check valve mechanism 20F.

[0067] In this embodiment, the support tube portion 40 is fixed to the plate body 14 by caulking, but the fixing method is not limited to this and may be any method such as welding, brazing, adhesive, screw fastening, etc. Also, the support tube portion 40 has through holes 43, 44 in the bottom wall and side wall, but may have a configuration in which a through hole is provided in either the bottom wall or the side wall. Furthermore, although an O-ring 24F is shown as the sealing member, it is not limited to an O-ring and may also be a packing. [Other Embodiments]

[0068] The cell container 11A of the above embodiment may be provided with a movable relief valve that is not a breakable type, so that when the electrolyte 91 is injected through the injection hole 22, the air inside the cell container 11A is exhausted from the relief valve.

[0069] The battery cells 10A, 10B of the above-described embodiment may be used in electric vehicles or hybrid vehicles, or as backup power sources for emergencies, and are not limited to specific uses.

[0070] The check valve mechanisms 20A to 20C, 20F are changed from a closed state to an open state by pressing the valve opening operation unit 27, but they may also be changed from a closed state to an open state by rotating or pulling the valve opening operation unit 27.

[0071] <Supplementary Notes> Below, the group of features extracted from the above embodiment will be explained, indicating, as necessary, the effects, etc. Note that, for ease of understanding, the corresponding configurations in the above embodiment will be indicated in parentheses as appropriate below, but these group of features are not limited to the specific configurations indicated in parentheses.

[0072] [Feature 1] The cell container (11A) of a battery cell (10A, 10B) includes: an injection hole (22) for allowing injection of an electrolyte (91) into the cell container (11A); check valve mechanisms (20A-20F) that allow the electrolyte (91) to pass into the cell container (11A) through the injection hole (22) while restricting the electrolyte (91) from passing out of the cell container (11A) through the injection hole (22); and a valve opening operation unit (27) that is provided in the check valve mechanisms (20A-20F) and applies an external force other than fluid pressure to open the check valve mechanisms (20A-20F).

[0073] [Feature 2] The cell container (11A) according to Feature 1, wherein all of the components constituting the check valve mechanism (20A to 20F) are made of non-conductive materials.

[0074] [Feature 3] All of the components constituting the check valve mechanism (20A to 20F) have a conductivity of 1.74 × 10 at 20°C. ６ The cell container (11A) according to Feature 1, wherein the cell container (11A) has a viscosity of 1000 kJ / m or less, or 3% IACS or less.

[0075] [Feature 4] A cell container (11A) according to Feature 1 or 3, wherein the container wall (14) of the cell container (11A) is made of metal, the check valve mechanisms (20A to 20F) include metal components, and all of the metals constituting the metal components have the same ionization tendency as the metals constituting the container wall (14).

[0076] [Feature 5] The cell container (11A) according to any one of Features 1, 3, and 4, further comprises a support cylindrical portion (21) that protrudes from the inner surface of the cell container (11A) and has the injection hole (22) on the inside; a movable body (23) that has a structure in which a flange portion (23B) protrudes from one end of a shaft portion (23A) that is loosely fitted into the support cylindrical portion (21) so as to be linearly movable, and the other end of the shaft portion (23A) serves as the valve-opening operation portion (27); a sealing member (24) that is overlapped on the flange portion (23B) and faces a tip end surface of the support cylindrical portion (21); and a spring member (26) that biases the movable body (23) so that the sealing member (24) is pressed against the tip end surface of the support cylindrical portion (21).

[0077] [Feature 6] The cell container (11A) according to Feature 5, wherein the movable body (23) is made of stainless steel or resin, and the spring member (26) is made of stainless steel.

[0078] [Feature 7] The check valve mechanism (20F) includes a cylindrical support tube (40) that is fixed to the inner surface of the container wall (14) of the cell container (11A) with one end opening overlapping the inner surface and has another opening at the other end or a side surface, a movable body (60) that is accommodated in the support tube (40) so as to be linearly movable, and a spring member (26) that is accommodated in the support tube (40) and biases the movable body (60) toward the container wall (14), the injection hole (22) penetrates the container wall (14), the movable body (60) has a valve body (63) that is overlapping within the opening of the injection hole (22) and can close the injection hole (22), and the part of the movable body (60) that faces the outside through the injection hole (22) is the valve opening operation unit (27).

[0079] [Feature 8] The cell container (11A) according to Feature 7, wherein the support cylinder portion (40) and the movable body (60) are made of resin, and the spring member (26) is made of stainless steel.

[0080] [Feature 9] The cell container (11A) according to Feature 7 or 8, further comprising an annular protrusion (14C) formed by protruding outward from the opening edge of the injection hole (22) in the container wall (14).

[0081] [Feature 10] The cell container (11A) according to any one of Features 1 to 9, wherein the injection hole (22) is arranged on the side surface or the bottom surface.

[0082] [Feature 11] An upper plate (13A) that is fixed to a container body (12A) having an open top and that, together with the container body (12A), constitutes the cell container (11A) described in any one of Features 1 to 10, the upper plate (13A) including the injection hole (22) having the check valve mechanism (20A to 20F).

[0083] [Feature 12] A check valve (20Z) is used in the cell container (11A) according to any one of Features 1 to 9, and is assembled in the injection hole (22) to constitute the check valve mechanism (20E), the check valve (20Z) including: a valve stem (33) fitted into the injection hole (22); a movable body (31) having a structure in which a flange portion (31B) projects from one end of a shaft portion (31A) supported on the valve stem (33) so as to be linearly movable, and the other end of the movable body (31) constitutes the valve-opening operation portion (27); a seal member (24E) overlapping the flange portion (31B) and facing one end face of the valve stem (33); and a spring member (26) that biases the movable body (31) so that the seal member (24E) is pressed against the one end face of the valve stem (33).

[0084] [Feature 13] A nozzle (50A to 50D, 50F) for injecting an electrolyte (91) into a cell container (11A) according to any one of Features 1 to 10, the nozzle (50A to 50D, 50F) comprising: an opening edge abutting portion (51) provided around a tip opening of the nozzle (50A to 50D, 50F) and abutting against an opening edge of the casting hole (22) in the cell container (11A); and a valve opening portion (52) that applies an external force to the valve opening operation portion (27) while the opening edge abutting portion (51) is abutting against the opening edge of the casting hole (22), thereby maintaining the check valve mechanism (20A to 20F) in an open state.

[0085] [Feature 14] A method for manufacturing a battery cell (10A, 10B), in which a plurality of electrode sheets (90A, 90B) and a plurality of separator sheets (90C) are housed in the cell container (11A) according to any one of Features 1 to 10, and an electrolyte (91) is injected into the cell container (11A) to manufacture the battery cell (10A, 10B), in which the electrolyte (91) is injected into the cell container (11A) while an external force is applied to the valve-opening operation unit (27) to maintain the check valve mechanisms (20A to 20F) in an open state.

[0086] [Feature 15] A method for manufacturing a battery cell (10A, 10B) in which a plurality of electrode sheets (90A, 90B) and a plurality of separator sheets (90C) are housed in the cell container (11A) according to any one of Features 1 to 10, and an electrolyte solution (91) is injected into the cell container (11A) to manufacture the battery cell (10A, 10B), wherein, after the electrolyte solution (91) is injected into the cell container (11A), a compressed gas is injected into the cell container (11A) to pressurize the inside of the battery cell (10A, 10B) in order to cause the electrolyte solution (91) to permeate between the electrode sheets (90A, 90B) and the separator sheet (90C).

[0087] [Feature 16] A method for manufacturing a battery cell (10A, 10B) having a cell container (11A) according to any one of Features 1 to 10, the method comprising: an electrolyte injection step of injecting an electrolyte (91) into the cell container (11A); an initial charging step of charging the battery cell (10A, 10B) after the electrolyte injection step; and a gas exhaust step of applying an external force to the valve opening operation unit (27) after the initial charging step to open the check valve mechanisms (20A to 20F), and exhausting gas generated in the battery cell (10A, 10B) from the cell container (11A) during the initial charging step.

[0088] [Feature 17] The method for manufacturing a battery cell (10A, 10B) according to Feature 16, wherein after the gas exhausting step, a closing member (28, 28E) is attached to the cell container (11A) to close the injection hole (22).

[0089] [Feature 18] A battery cell (10A, 10B) having the cell container (11A) according to any one of Features 1 to 10, wherein the battery cell (10A, 10B) comprises a closure member (28, 28E) that covers the injection hole (22) from the outside and is attached to the cell container (11A) to close the injection hole (22).

[0090] The cell container of Feature 1 includes a check valve mechanism that allows the electrolyte to pass into the cell container through the fill hole while restricting the electrolyte from passing out of the cell container, thereby preventing the electrolyte from leaking from the fill hole. Furthermore, the check valve mechanism is equipped with a valve opening operation unit that applies an external force other than fluid pressure to open the check valve mechanism, thereby increasing the flexibility of the manufacturing method for a battery cell using the cell container of Feature 1. Specifically, if a cell container having the structure of Feature 1 is used, a battery cell can be manufactured using the manufacturing methods of Features 14 to 16 above. Furthermore, if a blocking member that blocks the fill hole is not fixed to the battery cell, the battery cell can be easily recycled by filling it with an activator to restore the functionality of the deteriorated electrolyte. Note that battery cell manufacturing also includes battery cell recycling.

[0091] According to the cell containers of Features 2 and 3, the components constituting the check valve mechanism are all made of non-conductive materials or materials with relatively low conductivity, thereby preventing the check valve mechanism from functioning as an electrode.

[0092] Furthermore, as in Feature 4, by using metals with the same ionization tendency for the container wall of the cell container and the metal components that make up the check valve mechanism, corrosion of the check valve mechanism and the cell container is suppressed.

[0093] The check valve mechanism may have any structure as long as it can be opened by being pressed by a force other than fluid pressure. For example, it may have a movable body that is rotatably supported to open and close the injection hole, and a torsion spring that biases the valve body in the closing direction, with part of the valve body itself serving as the valve opening portion.

[0094] Furthermore, as in Feature 7, by configuring the check valve mechanism so that only the valve opening operation part faces the outside through the injection hole, adhesion of the electrolyte to the outside air side of the cell container is prevented, thereby suppressing corrosion of the cell container.

[0095] According to feature 8, the support cylinder portion and the movable body that come into contact with the stainless steel spring member are made of resin, so there is no contact between metals in the check valve mechanism, improving the durability of the check valve mechanism.

[0096] According to the cell container of feature 9, the annular protrusion can prevent the electrolyte from leaking from the filling hole.

[0097] The cell container of Feature 10 has an injection hole with a check valve mechanism located on the side or bottom surface, allowing the electrolyte to efficiently penetrate between the electrode membrane and the separator, which are located near the side or bottom surface.

[0098] According to feature 11, the cell container can be manufactured separately into the container body and the upper plate having the check valve mechanism, so that the check valve mechanism can be easily assembled, improving production efficiency.

[0099] The check valve of feature 12 is assembled into the injection hole of the cell container, so that the check valve and the other parts of the cell container can be produced separately, improving the production efficiency of each part.

[0100] The nozzle of feature 13 is provided with an opening edge abutting portion that abuts against the opening edge of the casting hole in the cell container, and a valve opening portion that presses the valve opening operating portion while the opening edge abutting portion is in contact with the opening edge of the casting hole, thereby maintaining the check valve mechanism in an open state. Therefore, when the electrolyte solution is injected into the cell container, fluid resistance caused by the check valve mechanism is reduced, allowing for smooth injection of the electrolyte solution and preventing the occurrence of hunting, which is the repeated opening and closing of the check valve mechanism.

[0101] In the battery cell manufacturing method of Feature 14, the electrolyte is injected into the cell container while the check valve mechanism is held in an open state. This reduces fluid resistance caused by the check valve mechanism when the electrolyte is injected, allowing for smooth injection of the electrolyte and preventing hunting, which is the repeated opening and closing of the check valve mechanism.

[0102] In the battery cell manufacturing method of Feature 15, after the electrolyte is injected into the cell container, compressed gas is injected into the cell container to pressurize the inside of the battery cell, which increases the rate at which the electrolyte permeates between the electrode film and the separator, improving production efficiency.

[0103] In conventional battery cell manufacturing methods, the electrolyte is injected into the cell container and the injection hole is sealed before initial charging, which causes a problem in that the inside of the cell container is pressurized by gas generated during initial charging before the battery is even used, making the cell container more susceptible to deformation and deterioration.In contrast, in the battery cell manufacturing method of Feature 16, the valve-opening operation part is pressed after the initial charging step to open the check valve mechanism, and gas generated inside the battery cell during the initial charging step is discharged from the cell container, thereby preventing the above problem from occurring.

[0104] According to Features 17 and 18, the filling hole is blocked by the blocking member, which prevents water or the like from entering the interior through the filling hole after the electrolyte is poured.

[0105] Although the present specification and drawings disclose specific examples of the technology included in the scope of the claims, the technology described in the claims is not limited to these specific examples, but also includes various modifications and variations of the specific examples, and also includes parts of the specific examples taken out alone.

[0106] DESCRIPTION OF SYMBOLS 10A, 10B Battery cell 11A Cell container 12A Container body 13A Upper plate 14 Plate body 20A to 20F Check valve mechanism 20Z Check valve 21, 21B, 21C, 40 Support cylinder portion 22 Injection hole 23, 23C, 30, 31, 60 Movable body 23A, 31A Shaft portion 23B, 31B Flange portion 24, 24C to 24E Packing (sealing member) 24F O-ring (sealing member) 26, 26D, 32 Spring member 27 Valve opening operation portion 28, 28E Closure member 33 Valve stem 50A to 50D, 50F Nozzle 51 Opening edge abutment portion 52 Valve opening portion 56R Direct acting rod (valve opening portion) 63 Valve body 90A Positive electrode sheet (electrode sheet) 90B Negative electrode sheet (electrode sheet) 90C Separator sheet 91 Electrolyte

Claims

1. A cell container for a battery cell, comprising: an injection hole for allowing injection of an electrolytic solution into the cell container; a check valve mechanism that allows the electrolytic solution to pass into the cell container at the injection hole while restricting the passage of the electrolytic solution out of the cell container at the injection hole; and an opening valve operation portion provided in the check valve mechanism for applying an external force other than fluid pressure to open the check valve mechanism.

2. The cell container according to claim 1, wherein all components constituting the check valve mechanism are made of non-conductive materials.

3. All components constituting the check valve mechanism have a conductivity at 20 °C of 1.74 × 10 ６ S / m or less, or 3% IACS or less. The cell container according to claim 1.

4. The cell container according to claim 1 or 3, wherein the container wall of the cell container is made of metal, the check valve mechanism includes metal components, and all metals constituting the metal components have the same ionization tendency as the metal constituting the container wall.

5. The cell container according to any one of claims 1, 3, and 4, wherein the check valve mechanism includes: a support cylinder portion protruding from the inner surface of the cell container and having an inner side that forms the injection hole; a movable body having a structure in which a flange portion projects from one end of a shaft portion that is loosely fitted to be linearly movable in the support cylinder portion, and the other end of the shaft portion forms the opening valve operation portion; a seal member that is overlaid on the flange portion and faces the tip surface of the support cylinder portion; and a spring member that biases the movable body so that the seal member is pressed against the tip surface of the support cylinder portion.

6. The cell container according to claim 5, wherein the movable body is made of stainless steel or resin, and the spring member is made of stainless steel.

7. The cell container according to any one of claims 1, 3, and 4, wherein the check valve mechanism includes: a support cylinder portion having a cylindrical shape and fixed with one end opening overlapping the inner surface of the container wall of the cell container and having another opening at the other end or side surface; a movable body accommodated in the support cylinder portion so as to be linearly movable; and a spring member accommodated in the support cylinder portion for biasing the movable body toward the container wall side, the injection hole penetrates the container wall, the movable body has a valve body that can overlap the opening of the injection hole to close the injection hole, and a portion of the movable body facing the outside through the injection hole forms the opening valve operation portion.

8. The cell container according to claim 7, wherein the support cylinder portion and the movable body are made of resin, and the spring member is made of stainless steel.

9. The cell container according to claim 7 or 8, comprising an annular protrusion formed by protruding the opening edge of the injection hole outward on the container wall.

10. The cell container according to any one of claims 1 to 9, wherein the injection hole is disposed on a side surface or a bottom surface.

11. An upper plate fixed to a container body with an open top, and constituting the cell container according to any one of claims 1 to 10 together with the container body, the upper plate comprising the injection hole having the check valve mechanism.

12. A check valve used in the cell container according to any one of claims 1 to 9, assembled in the injection hole and constituting the check valve mechanism, the check valve comprising: a valve stem fitted in the injection hole; a movable body having a structure in which a flange portion projects from one end of a shaft portion movably supported by the valve stem, and the other end serving as the valve opening operation portion; a seal member overlapped on the flange portion and facing one end surface of the valve stem; and a spring member biasing the movable body so that the seal member is pressed against one end surface of the valve stem.

13. A nozzle for injecting an electrolytic solution into the cell container according to any one of claims 1 to 10, the nozzle comprising: an opening edge abutting portion provided around the tip opening of the nozzle and abutting against the opening edge of the injection hole in the cell container; and a valve opening portion for applying an external force to the valve opening operation portion to hold the check valve mechanism in an open state in a state where the opening edge abutting portion abuts against the opening edge of the injection hole.

14. A method for manufacturing a battery cell, in which an electrolytic solution is injected into the cell container according to any one of claims 1 to 10 with a plurality of electrode sheets and a plurality of separator sheets accommodated therein to manufacture a battery cell, the method for manufacturing a battery cell comprising injecting the electrolytic solution into the cell container in a state where an external force is applied to the valve opening operation portion to hold the check valve mechanism in an open state.

15. A method for manufacturing a battery cell, wherein an electrolytic solution is injected into the cell container according to any one of claims 1 to 10 with a plurality of electrode sheets and a plurality of separator sheets accommodated therein to manufacture a battery cell, and after the electrolytic solution is injected into the cell container, compressed gas is injected into the cell container to pressurize the inside of the battery cell in order to permeate the electrolytic solution between the electrode sheet and the separator sheet.

16. A method for manufacturing a battery cell having a cell container according to any one of claims 1 to 10, comprising: an electrolytic solution injection step of injecting an electrolytic solution into the cell container; an initial charging step of charging the battery cell after the electrolytic solution injection step; and an exhaust gas step of applying an external force to the valve opening operation portion after the initial charging step to open the check valve mechanism and discharging the gas generated in the battery cell during the initial charging step from the cell container.

17. The method for manufacturing a battery cell according to claim 16, wherein after the exhaust gas step, a blocking member is attached to the cell container to block the injection hole.

18. A battery cell having a cell container according to any one of claims 1 to 10, comprising a blocking member that covers the injection hole from the outside and is attached to the cell container to block the injection hole.

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