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 pouring an electrolyte solution, and the filling hole is closed after the electrolyte solution is poured (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 aspect 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 having a check valve mechanism that allows electrolyte to be injected into the cell container while restricting leakage, 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] 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;

[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 made of, for example, a non-conductive metal, and the upper plate 13A is fixed to the container body 12A by welding or brazing them.

[0010] Although the cell container 11A in 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 or elliptical cylindrical shape, or other shapes. The container body 12A and the plate body 14 are made of a non-conductive metal, but they may also be made of resin or ceramics. Furthermore, while the cell container 11A in this embodiment is manufactured separately into the container body 12A and the upper plate 13A, for example, one side of the plate body 14 may be continuous with an opening edge of the container body 12A, so that the container body 12A and the upper plate 13A are manufactured as a single unit. Furthermore, when the container body 12A and the upper plate 13A are manufactured separately, their fastening is not limited to welding or brazing, and they may be fastened together by, for example, caulking, adhesive, screwing, etc. Furthermore, the term "fastening" in the following description may refer to any method, such as welding, brazing, caulking, adhesive, screwing, etc.

[0011] The pair of electrodes 15 described above are made of a conductive metal and have a structure in which, for example, support posts 15B extend upward from a rectangular support plate 15A as shown in Fig. 1 , and connection portions 15C protrude downward from the support plate 15A as shown in Fig. 2 . The support plate 15A of each pair of electrodes 15 is fixed to close a pair of through holes 15D formed at both longitudinal ends of the plate body 14 from above, and the connection portions 15C of each electrode 15 protrude 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 disc-shaped packing 24, for example, 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 positioned opposite 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] In addition, the movable body 23 in this embodiment may have any structure in which the flange portion 23B protrudes from the shaft portion 23A.For example, the flange portion 23B may be positioned midway along the axial direction of the shaft portion 23A, the flange portion 23B may have a disk structure with a central hole so that the shaft portion 23A is pressed into the central hole, or the flange portion 23B and the shaft portion 23A may be formed integrally.

[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] The components of the check valve mechanism 20A, such as the support tube portion 21, movable body 23, packing 24, locking ring 25, and spring member 26, are all formed of non-conductive materials. Specifically, the support tube portion 21 is part of the plate body 14 and is made of a non-conductive metal. The movable body 23, locking ring 25, and spring member 26 are also made of a non-conductive metal, and the packing 24 is made of rubber or soft resin. Examples of non-conductive metals that make up the movable body 23 and the like include aluminum, aluminum alloys, stainless steel, and iron alloys. Instead of non-conductive metals, the movable body 23 and the like may be made of non-metallic non-conductive materials such as resin or ceramics.

[0023] 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).

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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 ).

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] In addition, all of the components constituting the check valve mechanism 20A are made of non-conductive materials, which prevents the check valve mechanism 20A from functioning as an electrode. 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 of the check valve mechanism 20A can be easily performed, improving production efficiency.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] Furthermore, once the above-described gas exhaust process is completed, in order to reliably prevent foreign matter such as water from entering the battery cell 10A through the injection hole 22, a blocking member 28 may be superimposed and fixed to the outer surface of the plate body 14 so as to block the injection hole 22, as shown in FIG. 7 , or a cap-type blocking member (not shown) may be fitted or screwed onto the injection hole 22 to block the injection hole 22.

[0040] In addition, if the blocking member 28 is configured to be detachable from the injection hole 22, or if the blocking member 28 is not provided, for example, if 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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 above and below plate body 14, with injection hole 22 being the inside of 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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."

[0055] 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.

[0056] Although the check valve mechanisms 20A are disposed on three surfaces of the battery cell 10B in this embodiment, namely, the top surface, the side surfaces, and the bottom surface, the check valve mechanisms 20A may be disposed on any multiple surfaces of the battery cell 10B, or on any single surface.

[0057] 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 is injected through the injection hole 22, the air inside the cell container 11A is exhausted from the relief valve.

[0058] 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.

[0059] The check valve mechanisms 20A to 20B are changed from a closed state to an open state by pressing the valve opening operation part 27, but they may also be changed from a closed state to an open state by rotating or pulling the valve opening operation part 27.

[0060] <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.

[0061] [Feature 1] A cell container (11A) for a battery cell (10A, 10B), comprising: an injection hole (22) having a check valve mechanism (20A-20E) that allows injection of an electrolyte (91) into the cell container (11A) while restricting outflow; and a valve opening operation unit (27) that is provided in the check valve mechanism (20A-20E) and applies an external force other than fluid pressure to open the check valve mechanism (20A-20E). [Feature 2] The cell container (11A) according to Feature 1, wherein all of the components that make up the check valve mechanism (20A-20E) are made of non-conductive materials.

[0062] [Feature 3] The check valve mechanism (20A to 20E) includes: a support cylindrical portion (21) that protrudes from the inner surface of the cell container (11A) and has the injection hole (22) on its 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 packing (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 packing (24) is pressed against the tip end surfaces of the support cylindrical portions (21, 21B, 21C).

[0063] [Feature 4] The cell container (11A) according to Feature 3, wherein the movable body (23) is made of aluminum, stainless steel, or resin, the packing (24) is made of rubber or soft resin, and the spring member (26) is a stainless steel compression coil spring.

[0064] [Feature 5] The cell container (11A) according to any one of Features 1 to 4, wherein the injection hole (22) is arranged on the side surface or the bottom surface.

[0065] [Feature 6] 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 4, the upper plate (13A) including the injection hole (22) having the check valve mechanism (20A to 20E).

[0066] [Feature 7] A check valve (20Z) is used in the cell container (11A) according to any one of Features 1 to 5, and is assembled in the injection hole (22) to constitute the check valve mechanism (20A to 20E). The check valve (20Z) is composed of a plurality of parts made of non-conductive materials, and the plurality of parts include: a valve stem (33) that is fitted into the injection hole (22); a movable body (31) that has a structure in which a flange portion (31B) projects from one end of a shaft portion (31A) that is supported on the valve stem (33) so as to be capable of linear movement, and the other end of the movable body (31) serves as the valve-opening operation portion (27); a packing (24E) that is overlapped on the flange portion (31B) and faces one end face of the valve stem (33); and a spring member (32) that biases the movable body (23) so that the packing (24E) is pressed against the one end face of the valve stem (33).

[0067] [Feature 8] A nozzle (50A to 50D) for injecting an electrolyte (91) into a cell container (11A) according to any one of Features 1 to 5, the nozzle (50A to 50D) comprising: an opening edge abutting portion (51) provided around a tip opening of the nozzle (50A to 50D) 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 20E) in an open state.

[0068] [Feature 9] 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 5, 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 20E) in an open state.

[0069] [Feature 10] 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 5, 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).

[0070] [Feature 11] A method for manufacturing a battery cell (10A, 10B) having a cell container (11A) according to any one of Features 1 to 5, 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-20E), and exhausting gas generated in the battery cell (10A, 10B) from the cell container (11A) during the initial charging step.

[0071] [Feature 12] The method for manufacturing a battery cell (10A, 10B) according to Feature 11, wherein after the gas exhausting step, a lid member is attached to the cell container (11A) to close the injection hole (22).

[0072] [Feature 13] A battery cell (10A, 10B) having the cell container (11A) according to any one of Features 1 to 5, 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).

[0073] The cell container of Feature 1 is equipped with a check valve mechanism in the fill hole, thereby preventing the problem of electrolyte 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 battery cells using the cell container of Feature 1. Specifically, if a cell container with the structure of Feature 1 is used, battery cells can be manufactured using the manufacturing methods of Features 8 to 10 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.

[0074] Although the structure of the check valve mechanism includes Feature 3, any structure may be used 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.

[0075] In the cell containers of Features 2 and 4, all of the components constituting the check valve mechanism are made of non-conductive materials, which prevents the check valve mechanism from functioning as an electrode.

[0076] The cell container of Feature 5 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.

[0077] According to feature 6, 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.

[0078] The check valve of Feature 7 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.

[0079] The nozzle of Feature 8 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 is injected into the cell container, fluid resistance caused by the check valve mechanism is reduced, allowing for smooth injection of the electrolyte and preventing the occurrence of hunting, which is the repeated opening and closing of the check valve mechanism.

[0080] In the battery cell manufacturing method of Feature 9, the electrolyte is injected into the cell container while the check valve mechanism is held open. 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.

[0081] In the battery cell manufacturing method of Feature 10, after the electrolyte is injected into the cell container, compressed gas is injected into the cell container to create a pressurized state inside the battery cell, which increases the rate at which the electrolyte permeates between the electrode film and the separator, improving production efficiency.

[0082] 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 11, 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.

[0083] According to Features 12 and 13, 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.

[0084] 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.

[0085] DESCRIPTION OF SYMBOLS 10A, 10B Battery cell 11A Cell container 12A Container body 13A Upper plate 14 Plate body 20A to 20E Check valve mechanism 20Z Check valve 21 Support cylinder portion 22 Injection hole 23, 23C, 30, 31 Movable body 23A, 31A Shaft portion 23B, 31B Flange portion 24, 24C to 24E Packing 26, 26D, 32 Spring member 27 Valve opening operation portion 28, 28E Closure member 33 Valve stem 50A to 50D Nozzle 51 Opening edge abutment portion 52 Valve opening portion 56R Direct acting rod (valve opening portion) 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 having a check valve mechanism that allows injection of an electrolytic solution into the cell container while restricting outflow, 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. 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 the support cylinder portion so as to be linearly movable, and the other end of the shaft portion forms the opening valve operation portion, a packing 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 packing is pressed against the tip surface of the support cylinder portion. The cell container according to claim 2.

4. The movable body is made of aluminum, stainless steel, or resin, the packing is made of rubber or soft resin, and the spring member is a stainless steel compression coil spring. The cell container according to claim 3.

5. The cell container according to any one of claims 1 to 4, wherein the injection hole is disposed on a side surface or a bottom surface.

6. An upper plate fixed to a container body with an open top surface and constituting the cell container according to any one of claims 1 to 5 together with the container body, the upper plate including the injection hole having the check valve mechanism.

7. A check valve used in the cell container according to any one of claims 1 to 5 and assembled in the injection hole to constitute the check valve mechanism, the check valve being composed of a plurality of non-conductive components, the plurality of components including a valve stem fitted into the injection hole, a movable body having a structure in which a flange portion projects from one end of a shaft portion that is linearly movably supported by the valve stem and the other end forms the opening valve operation portion, a packing that is overlaid on the flange portion and faces one end surface of the valve stem, and a spring member that biases the movable body so that the packing is pressed against one end surface of the valve stem.

8. A nozzle for injecting an electrolytic solution into the cell container according to any one of claims 1 to 5, comprising: an opening edge contact portion provided around the tip opening of the nozzle and contacting 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 when the opening edge contact portion contacts the opening edge of the injection hole.

9. 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 5 with a plurality of electrode sheets and a plurality of separator sheets accommodated therein to manufacture a battery cell, the method comprising injecting the electrolytic solution into the cell container while an external force is applied to the valve opening operation portion to hold the check valve mechanism in an open state.

10. 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 5 with a plurality of electrode sheets and a plurality of separator sheets accommodated therein to manufacture a battery cell, the method comprising injecting compressed gas into the cell container to pressurize the inside of the battery cell after the electrolytic solution is injected into the cell container in order to permeate the electrolytic solution between the electrode sheet and the separator sheet.

11. A method for manufacturing a battery cell having the cell container according to any one of claims 1 to 5, the method 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 discharging gas generated in the battery cell during the initial charging step from the cell container by applying an external force to the valve opening operation portion to open the check valve mechanism after the initial charging step.

12. The method for manufacturing a battery cell according to claim 11, wherein a closing member is attached to the cell container to close the injection hole after the exhaust gas step.

13. A battery cell having the cell container according to any one of claims 1 to 5, the battery cell comprising a closing member that covers the injection hole from the outside and is attached to the cell container to close the injection hole.

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