Manufacturing apparatus and manufacturing method of electrochemical cell

Abstract

A manufacturing apparatus includes a chamber, a pressure reducing device, and a return piping. The pressure reducing device is configured to reduce pressure within the chamber. The return piping includes a first opening, a conduit, and a second opening. The first and second openings are independently located within the chamber. The first opening is connected to an outer casing. The conduit connects the first and second openings. The conduit is configured to temporarily exhaust gas from the outer casing to the outside of the chamber when pressure has been reduced within the chamber, and then return the exhausted gas to the chamber. This manufacturing apparatus maintains the internal pressure of the battery by minimizing obstruction of the gas flow path when pressure is reduced within the outer casing.

Description

Technical Field

[0001] This disclosure relates to a manufacturing apparatus and a method for manufacturing an electrochemical cell. Background Technology

[0002] Japanese Patent Application Publication No. 2018-106850 discloses a liquid injection device and liquid injection method that can improve the production efficiency of energy storage modules. Summary of the Invention

[0003] Generally, electrochemical batteries (hereinafter referred to as "batteries") are manufactured by housing components such as power generation elements and electrolytes within an outer casing. During battery use, gas may be generated within the outer casing, for example, due to electrolyte degradation. The internal pressure of the outer casing may increase due to gas generation. Considering subsequent gas generation, it is desirable to minimize the amount of gas within the outer casing during the manufacturing process. Therefore, the pressure inside the outer casing is sometimes reduced. For example, this is done using a vacuum pump. Once the pressure (decompression) within the outer casing reaches the target value, the outer casing is sealed.

[0004] Sometimes, a low-rigidity outer casing is used. For example, sheet-like outer casings such as metal foil laminates are sometimes used. When the outer casing has low rigidity, it may deform under external pressure when the pressure inside is reduced. The gas flow path may become blocked due to the deformation of the outer casing. If the gas flow path is blocked, the target pressure reduction may not be achieved inside the outer casing even if the pressure gauge reading reaches the target value.

[0005] This disclosure provides a manufacturing apparatus and a method for manufacturing an electrochemical cell, which maintains internal pressure by reducing blockage of gas flow paths during depressurization within the external assembly.

[0006] The manufacturing apparatus of the first aspect of the present invention is an apparatus for manufacturing an electrochemical cell with depressurized internal components. The manufacturing apparatus includes a chamber, a depressurization device, and a return pipe. The depressurization device is configured to depressurize the chamber. The return pipe includes a first opening, a conduit, and a second opening. The first and second openings are independently located within the chamber. The first opening is configured to connect to the external component. The conduit connects the first and second openings. The conduit is configured to temporarily exhaust gas from the external component to the outside of the chamber when the chamber has been depressurized, and then return the exhaust gas to the chamber.

[0007] In the manufacturing apparatus of the first embodiment described above, the reflux piping may also comprise a plurality of independent reflux piping. Each of the plurality of reflux piping may also independently comprise the first opening, the pipe, and the second opening.

[0008] The manufacturing apparatus of the first embodiment described above may also include a pressure gauge. The pressure gauge may also be connected to the pipeline.

[0009] The manufacturing apparatus of the first embodiment may also include a flow meter. The flow meter may also be connected to the pipeline.

[0010] The manufacturing apparatus of the first embodiment described above may also include a sealing device. The sealing device may also be configured to seal the outer casing within the cavity.

[0011] The manufacturing method of the electrochemical battery of the second aspect of the present invention includes the following steps: preparing the manufacturing apparatus of the first aspect; preparing a workpiece by housing a power generation element in the outer casing; placing the workpiece in the chamber; connecting the outer casing and the first opening; and depressurizing the outer casing via the return pipe by depressurizing the chamber.

[0012] In the manufacturing method of the second embodiment, the manufacturing apparatus may be prepared in the step of preparing the manufacturing apparatus, which includes a plurality of independent reflux pipes, and a battery module including a plurality of electrochemical cells may be prepared as the workpiece in the step of preparing the workpiece. The plurality of electrochemical cells may also each have an independent internal space, and in the step of connecting the outer casing and the first opening, the reflux pipes may be connected to each of the plurality of internal spaces separately.

[0013] In the manufacturing method of the second embodiment, the manufacturing apparatus, which includes a pressure gauge, may be prepared during the step of preparing the manufacturing apparatus. Alternatively, during the step of depressurizing the outer casing, the pressure may be reduced in such a way that the pressure gauge reading falls below a reference value.

[0014] In the manufacturing method of the second embodiment, the manufacturing apparatus including the flow meter may be prepared during the step of preparing the manufacturing apparatus. Alternatively, during the step of depressurizing the outer casing, the depressurization may be performed such that the cumulative value of the flow meter's measurement reaches or exceeds a reference value after the depressurization is stopped.

[0015] The manufacturing method of the second embodiment may also include forming an injection port on the outer casing and injecting electrolyte into the outer casing through the injection port. In the step of connecting the outer casing and the first opening, the first opening of the return pipe may also be connected to the injection port.

[0016] In the manufacturing method of the second embodiment, the outer casing may also contain at least one selected from metal foil and metal foil laminate.

[0017] In the manufacturing method, a bipolar battery module can also be prepared as the workpiece during the process of preparing the workpiece.

[0018] The manufacturing method of the second embodiment may also include sealing the outer casing under reduced pressure.

[0019] The embodiments of this disclosure (hereinafter referred to as "this embodiment") and the examples of this disclosure (hereinafter referred to as "this example") will be described below. However, this embodiment and this example do not limit the technical scope of this disclosure. Attached Figure Description

[0020] Hereinafter, the features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described with reference to the accompanying drawings, in which the same reference numerals denote the same elements.

[0021] Figure 1 This is the first conceptual diagram of the decompression state.

[0022] Figure 2 This is the second conceptual diagram of the decompression state.

[0023] Figure 3 This is a conceptual diagram representing an example of a battery module.

[0024] Figure 4 This is a conceptual diagram illustrating an example of a manufacturing apparatus according to this embodiment.

[0025] Figure 5 This is a schematic flowchart of the manufacturing method of the electrochemical battery according to this embodiment.

[0026] Figure 6 This is a schematic cross-sectional view of the first, second, and third units of this embodiment.

[0027] Figure 7 This is a schematic cross-sectional view of the bipolar battery module of this embodiment.

[0028] Figure 8 This is a schematic top view of the bipolar battery module of this embodiment.

[0029] Figure 9 This is a concept map representing comparative examples. Detailed Implementation

[0030] In this specification, the terms "possessing," "comprising," "having," and variations thereof (e.g., "consisting of," etc.) are open-ended. An open-ended description may include additional elements in addition to the essential elements, or it may not include additional elements. The description "composed of," is closed-ended. However, even in closed-ended descriptions, there are usually incidental additions, not excluding additional elements unrelated to the technology disclosed herein. The description "substantially composed of," is semi-closed-ended. In semi-closed-ended descriptions, it is permissible to add elements that do not substantially affect the basic and novel characteristics of the technology disclosed herein.

[0031] In this instruction manual, expressions such as "may also" and "may" do not mean "must" in the strict sense, but rather "there is a possibility".

[0032] In this specification, the order in which the various steps, actions, and operations involved in the methods are performed is not limited to the order described, unless otherwise specified. For example, multiple steps may be performed simultaneously. For example, multiple steps may be performed sequentially.

[0033] Geometric terms in this specification (such as "parallel," "perpendicular," "orthogonal," etc.) should not be understood in a strict sense. For example, "parallel" may deviate slightly from the strict meaning of "parallel." Geometric terms in this specification may include tolerances and errors, such as design, operational, and manufacturing tolerances. Dimensional relationships in the drawings may sometimes differ from actual dimensional relationships. To aid in understanding the technology disclosed herein, dimensional relationships (length, width, thickness, etc.) in the drawings may sometimes be altered. Furthermore, some structural elements may be omitted at times.

[0034] In this specification, an "electrochemical battery" refers to a single device that converts chemical energy into electrical energy. Electrochemical batteries include primary batteries and secondary batteries. They include lithium-ion batteries and nickel-metal hydride batteries. Lithium-ion batteries include liquid-state batteries and all-solid-state batteries. In this specification, a "battery module" refers to an assembly of multiple electrochemical batteries. Multiple electrochemical batteries may or may not be electrically connected. Multiple electrochemical batteries may form a series circuit or a parallel circuit.

[0035] In this specification, "pressure reduction degree" refers to the magnitude of the gas pressure remaining inside the outer casing after pressure reduction. Pressure reduction degree can also be referred to as vacuum degree.

[0036] Summary of this implementation method

[0037] First, a summary of this embodiment will be given. Furthermore, the mechanism of action in this specification includes assumptions. The mechanism of action does not limit this embodiment.

[0038] 1. A manufacturing apparatus for manufacturing electrochemical cells with depressurized contents. The manufacturing apparatus includes a chamber, a depressurization device, and a return piping. The depressurization device is configured to depressurize the contents within the chamber. The return piping includes a first opening, a conduit, and a second opening. The first and second openings are independently located within the chamber. The first opening is configured to connect to the outer casing. The conduit connects the first and second openings. The conduit extends in a manner that temporarily exhausts gas from the outer casing to the outside of the chamber when the contents have been depressurized, and then returns the exhausted gas to the chamber.

[0039] Figure 1 This is the first conceptual diagram of the decompression state.

[0040] By venting the gas inside the outer casing 210, the internal pressure P inside the outer casing 210 is reduced. I Become less than the external pressure P E That is, the interior of the outer casing 210 is under negative pressure relative to the surrounding atmosphere. This is because the internal space of the outer casing 210 is under negative pressure due to the external pressure P. E If it is flattened, the gas flow path may be blocked.

[0041] Figure 2 This is the second conceptual diagram of the decompression state.

[0042] Figure 2 The white arrows indicate airflow. In the manufacturing apparatus described above ("1"), the gas inside the outer casing 210 can be discharged via the return pipe 140. By reducing the pressure inside chamber 110, the pressure in chamber 110 (external pressure P) is reduced. E This reduces the pressure. Pressure loss may occur in the return piping 140. Therefore, the internal pressure P within the outer casing 210 decreases. I It may become greater than the external pressure P E That is, the outer casing 210 can be kept under positive pressure relative to the surrounding atmosphere (the atmosphere inside chamber 110). It is assumed that by maintaining a positive pressure state during decompression, the internal space of the outer casing 210 is less susceptible to damage from external pressure P. E And it is flattened. That is, it is believed that blockage of the gas flow path is unlikely to occur.

[0043] 2. The manufacturing apparatus may also include multiple return piping. Each of the multiple return piping independently includes a first opening, a pipe, and a second opening.

[0044] In the manufacturing apparatus described in "1" above, for example, a single battery can be manufactured. In the manufacturing apparatus described in "2" above, for example, a battery module can also be manufactured. It is considered that the manufacturing apparatus described in "2" above is suitable for manufacturing battery modules.

[0045] Figure 3 This is a conceptual diagram representing an example of a battery module.

[0046] Battery module 250 includes separator 230. Separator 230 separates adjacent batteries 200 from each other. In the outer batteries 200, if the gas flow path is blocked due to deformation of the outer casing 210, the occurrence of blockage can be detected by appearance. Figure 3 The white arrow in the image indicates an example of the direction of deformation. For instance, in the inner battery 200, if the separator 230 deforms and blocks the gas flow path, it is difficult to detect the blockage by visual inspection.

[0047] It is believed that by connecting each return pipe to each battery, it is possible to depressurize each battery while maintaining a positive pressure. This is thought to reduce gas flow blockage in the inner batteries.

[0048] In the manufacturing apparatus described in "2" above, the pressure reduction target is one chamber. Therefore, multiple batteries can be depressurized simultaneously using a single pressure reduction device.

[0049] 3. The manufacturing apparatus may also include a pressure gauge. The pressure gauge is connected to a pipeline.

[0050] The pressure level of each battery can be determined using a pressure gauge.

[0051] 4. The manufacturing apparatus may also include a flow meter. The flow meter is connected to the pipeline.

[0052] For example, the total amount of gas discharged can be determined by accumulating the measurements in the flow meter. Similarly, the pressure reduction of each battery can be determined based on the total amount of gas discharged and the internal space (volume) within the casing.

[0053] 5. The manufacturing apparatus may also include a sealing device. The sealing device may be configured to seal the outer casing within the chamber.

[0054] 6. The method for manufacturing an electrochemical cell includes the steps (a) to (e) below.

[0055] Step (a) Prepare the manufacturing apparatus for “1” above.

[0056] Step (b) prepares the workpiece by housing the power generation element within the outer casing.

[0057] Step (c) involves placing the workpiece inside the cavity.

[0058] Step (d) connects the outer casing to the first opening.

[0059] Step (e) depressurizes the external assembly via the return piping by depressurizing the chamber.

[0060] The manufacturing apparatus described in "1" can be used, for example, in step "6" described above.

[0061] 7. In step (a) above, for example, a manufacturing apparatus comprising multiple independent reflux pipes can also be prepared. In step (b) above, a battery module comprising multiple electrochemical cells can also be prepared as a workpiece. Each of the multiple electrochemical cells independently comprises an internal space. In step (d) above, reflux pipes can also be connected to each of the multiple internal spaces separately.

[0062] The manufacturing method described in "7" above can be used to manufacture battery modules. The battery module can be either bipolar or unipolar. In a bipolar module, the electrode has two polarities. For example, the front side of the electrode is the positive electrode, and the back side is the negative electrode. This electrode can also be called a bipolar electrode. In a unipolar module, the electrode has a single polarity. That is, the electrode is either a positive or a negative electrode.

[0063] 8. In step (a) above, for example, a manufacturing apparatus including a pressure gauge may also be prepared. In step (e) above, the pressure may be reduced in the external casing such that the pressure gauge reading falls below a reference value.

[0064] For example, the pressure can be confirmed using a pressure gauge.

[0065] 9. In step (a) above, a manufacturing apparatus including a flow meter may also be prepared. In step (e) above, the pressure may be reduced within the external assembly such that the cumulative value of the flow meter's measurement after the pressure reduction is stopped reaches or exceeds a reference value.

[0066] For example, a flow meter can be used to confirm the pressure reduction. Alternatively, a pressure gauge and a flow meter can be used in combination to confirm the pressure reduction.

[0067] 10. An injection port may also be formed on the outer casing. Electrolyte can be injected into the outer casing through the injection port. In step (d) above, the first opening of the return piping may also be connected to the injection port.

[0068] For example, gas can be discharged from the injection port of the outer casing.

[0069] 11. The outer casing may also contain at least one selected from metal foil and metal foil laminate.

[0070] Metal foils and metal foil laminates can have low rigidity. The manufacturing method described in "6" above is considered suitable for cases where the outer casing has low rigidity.

[0071] 12. In step (b) above, a bipolar battery module can also be prepared as a workpiece.

[0072] The manufacturing method described in "7" above is considered suitable for bipolar battery modules.

[0073] 13. The manufacturing method of an electrochemical cell may also include the following step (f).

[0074] (f) Seal the outer casing under reduced pressure.

[0075] Details of this implementation method

[0076] Next, the details of this embodiment will be explained.

[0077] Manufacturing equipment

[0078] Figure 4 This is a conceptual diagram illustrating an example of a manufacturing apparatus according to this embodiment.

[0079] Hereinafter, "the manufacturing apparatus of this embodiment" may be simply referred to as "this manufacturing apparatus". This manufacturing apparatus 100 includes a chamber 110, a pressure reducing device 130, and a return pipe 140. This manufacturing apparatus 100 may also include, for example, a sealing device 120, a pressure gauge 150, and a flow meter 160.

[0080] The chamber 110 provides a stable, sealed space under depressurization conditions. The chamber 110 can be, for example, a metal container. The chamber 110 may include, for example, an exhaust port 111. The exhaust port 111 can be connected to the depressurization device 130. Within the chamber 110, for example, a platform, support, etc. (not shown) may be provided. The workpiece 201 can be held on the platform, support, etc.

[0081] The sealing device 120 can be configured to seal the outer body 210, for example, within the chamber 110. The sealing device 120 can also be configured to seal the outer body 210 outside the chamber 110. The sealing device 120 can seal the outer body 210 using any method. The sealing device 120 can include, for example, a heat fusion device, an ultrasonic welding device, etc. The sealing device 120 can be disposed within, for example, the chamber 110. For example, a portion of the sealing device 120 can be disposed within the chamber 110. For example, the portion that actually performs the seal can be disposed within the chamber 110. The portion that performs the seal can include, for example, a pressurizing unit, a heating rod, a heating plate, an ultrasonic welding head, an anvil, etc. The sealing device 120 can also be disposed outside, for example, the chamber 110.

[0082] The pressure reducing device 130 is configured to reduce the pressure inside the chamber 110. The pressure reducing device 130 may include, for example, a vacuum pump or a compressor.

[0083] The return piping 140 has sufficient strength to withstand external pressure without deformation during pressure reduction. The return piping 140 can be, for example, made of metal. The return piping 140 includes a first opening 141, a conduit 143, and a second opening 142. The first opening 141 and the second opening 142 each open independently within the chamber 110. The positions of the first opening 141 and the second opening 142 can be arbitrary as long as they are not identical. The first opening 141 is configured to connect to the outer casing 210. For example, a clamp for connecting to the outer casing 210 can be mounted to the first opening 141.

[0084] Pipe 143 connects the first opening 141 and the second opening 142. The first opening 141 is located at one end of pipe 143. The second opening 142 is located at the other end of pipe 143. Figure 4 The white arrows in the diagram indicate airflow. The conduit 143 extends in such a manner that when the pressure is reduced within the chamber 110, the gas inside the outer casing 210 is temporarily discharged to the outside of the chamber 110, and then the discharged gas returns to the chamber 110. That is, if the pressure is reduced within the chamber 110, gas inside the outer casing 210 is drawn in from the first opening 141. The drawn gas passes through the conduit 143 and is discharged into the chamber 110 from the second opening 142. Pressure loss is assumed to occur within the conduit 143. Due to this pressure loss, the outer casing 210 may be under positive pressure relative to the atmosphere within the chamber 110. By reducing the pressure within the outer casing 210 under positive pressure, blockage of the gas flow path within the outer casing 210 can be reduced.

[0085] Pipe 143 can have an inner diameter of, for example, 1–10 mm, or 2–6 mm. A suitable pressure loss can be generated when the inner diameter is 1–10 mm. The inner diameter of pipe 143 can be constant or variable. Pressure loss can also be generated by changing the inner diameter. Pipe 143 can, for example, have multiple bends. Pressure loss can be generated at the bends.

[0086] The manufacturing apparatus 100 may include a single return pipe 140. The manufacturing apparatus 100 may also include multiple return pipes 140. Figure 4 The diagram illustrates three return pipes 140 as an example. Each of the plurality of return pipes 140 independently includes a first opening 141, a conduit 143, and a second opening 142. By including the plurality of return pipes 140 in this manufacturing apparatus 100, a battery module 250 can be manufactured. The number of return pipes 140 may correspond to the number of batteries 200 contained in the battery module 250.

[0087] The manufacturing apparatus 100 may further include a pressure gauge 150. The pressure gauge 150 is connected to the conduit 143. The pressure gauge 150 with an appropriate pressure range can be selected according to the target pressure reduction. The pressure reduction within the outer casing 210 can be confirmed based on the reading of the pressure gauge 150. In the case where the manufacturing apparatus 100 includes a plurality of return pipes 140, the pressure gauge 150 can be connected to each of the plurality of return pipes 140.

[0088] The manufacturing apparatus 100 may further include a flow meter 160. The flow meter 160 is connected to the pipe 143. The flow meter 160 with an appropriate flow range can be selected according to the gas flow rate. The gas flow rate is measured by the flow meter 160. The cumulative value of the measurement is considered as the total amount of gas discharged. The pressure reduction of the outer casing 210 can be determined based on the total amount of gas discharged and the internal space within the outer casing 210. In the case where the manufacturing apparatus 100 includes multiple return pipes 140, the flow meter 160 can be connected to each of the multiple return pipes 140.

[0089] Manufacturing method of electrochemical battery

[0090] Figure 5 This is a schematic flowchart of the manufacturing method of the electrochemical battery according to this embodiment.

[0091] Hereinafter, "the method for manufacturing the electrochemical cell according to this embodiment" may be simply referred to as "this manufacturing method". This manufacturing method includes "(a) preparation of the manufacturing apparatus", "(b) preparation of the workpiece", "(c) arrangement of the workpiece", "(d) connection to the reflux piping", and "(e) pressure reduction". This manufacturing method may also include, for example, "(f) sealing". Furthermore, Figure 5 The order of the records is formal. For example, “(a) preparation of the manufacturing apparatus” and “(b) preparation of the workpiece” can be reversed.

[0092] (a) Preparation of manufacturing equipment

[0093] This manufacturing method includes preparing the manufacturing apparatus 100. Details of the manufacturing apparatus 100 are as described above.

[0094] (b) Preparation of the workpiece

[0095] This manufacturing method includes preparing a workpiece 201 by housing a power generation element 220 within an outer casing 210. The workpiece 201 is a so-called "pre-sealed battery." For example, a bipolar battery module can be prepared as workpiece 201. A bipolar battery module contains multiple batteries. A bipolar battery module can contain, for example, 1 to 100 batteries, 10 to 50 batteries, or 20 to 40 batteries. Here, "bipolar battery module" is simply referred to as "battery module."

[0096] Figure 6 This is a schematic cross-sectional view of the first, second, and third units of this embodiment. The battery module 250 can be formed from the first unit 251, the second unit 252, and the third unit 253. The first unit 251 and the third unit 253 are disposed at opposite ends in the stacking direction (Z-axis direction). The second unit 252 is stacked between the first unit 251 and the third unit 253.

[0097] The outer casing 210 is sheet-like. The outer casing 210 can function as a current collector. The outer casing 210 may contain at least one selected from metal foil and metal foil laminate. The metal foil laminate can be formed by coating the metal foil with a resin layer. The resin layer may contain, for example, polypropylene (PP), polyethylene terephthalate (PET), etc. The metal foil may contain, for example, at least one selected from aluminum (Al) foil, stainless steel (SUS) foil, nickel (Ni) foil, titanium (Ti) foil, and copper (Cu) foil. For example, the metal foil may be plated. For example, the SUS foil may be plated with Ni. The outer casing 210 may contain, for example, at least one selected from Al foil and Al foil laminate.

[0098] The first unit 251 is prepared by forming a positive electrode layer 10 on one side of an outer casing 210. The positive electrode layer 10 contains a positive electrode active material. The positive electrode active material may contain, for example, lithium nickel cobalt manganese oxide, lithium iron phosphate, etc. The positive electrode layer 10 may also contain, for example, conductive materials, binders, solid electrolytes, etc.

[0099] A negative electrode layer 20 is formed on one side of another outer casing 210. The negative electrode layer 20 contains a negative electrode active material. The negative electrode active material may contain, for example, graphite, silicon, silicon oxide, etc. The negative electrode layer 20 may also contain, for example, a conductive material, an adhesive, a solid electrolyte, etc. The third unit 253 is prepared by attaching a separator 30 to the surface of the negative electrode layer 20. The separator 30 may comprise, for example, a porous membrane. The porous membrane may contain, for example, a polyolefin, etc. The separator 30 may comprise, for example, a solid electrolyte layer.

[0100] The separator 230 is sheet-like. The separator 230 can be formed of the same material as the outer casing 210, or it can be formed of a different material. The separator 230 can function as a current collector. The separator 230 can contain, for example, a metal foil. The separator 230 can contain, for example, an Al foil. A positive electrode layer 10 is formed on one side of the separator 230. A negative electrode layer 20 is formed on the opposite side of the side where the positive electrode layer 10 is formed. A bipolar electrode is formed by integrating the positive electrode layer 10, the separator 230, and the negative electrode layer 20. In the bipolar electrode, a second unit 252 is prepared by attaching a separator 30 to the surface of the negative electrode layer 20.

[0101] Figure 7This is a schematic cross-sectional view of the bipolar battery module according to this embodiment. The battery module 250 is formed by stacking the first unit 251, the second unit 252, ..., the second unit 252, and the third unit 253. A set of positive electrode layer 10, separator 30, and negative electrode layer 20 forms a power generation element 220. The battery 200 is formed by sandwiching the power generation element 220 between two separators 230. At both ends in the stacking direction, the power generation element 220 is held by the separators 230 and the outer casing 210, thereby forming the battery 200. Each battery 200 independently contains an internal space.

[0102] The outer casing 210 includes a sealing material 240. For example, the sealing material 240 may be configured to fill the periphery of the power generation element 220. The sealing material 240 may contain, for example, a thermoplastic resin (PP, etc.). An injection port 241 may be formed in part of the sealing material 240. That is, the injection port 241 may be formed in the outer casing 210. The injection port 241 is an opening that can serve as a liquid flow path and a gas flow path. Electrolyte can be injected into each battery 200 from the injection port 241. That is, electrolyte can be injected into the outer casing 210 from the injection port 241.

[0103] Figure 8 This is a schematic top view of the bipolar battery module of this embodiment. The top view shape of the battery module 250 is arbitrary. For example, the top view shape of the battery module 250 can be rectangular. The sealing material 240 can be configured to surround the outer casing 210. Furthermore, Figure 8 The AA line cross-section diagram is Figure 7 .

[0104] For example, a unipolar battery module can be prepared as workpiece 201. For example, the separator 230 can be composed of multiple sheet-like members. In this case, a positive electrode layer 10 is formed on one side of one sheet-like member of the separator 230. A negative electrode layer 20 is formed on one side of another sheet-like member of the separator 230. A unipolar battery is constructed by overlapping one sheet-like member and another sheet-like member with the positive electrode layer 10 and negative electrode layer 20 facing each other. Between adjacent unipolar batteries, the opposite sides of the positive electrode layer 10 of one sheet-like member contained in one battery and the negative electrode layer 20 of another sheet-like member contained in another battery are overlapped, thereby constructing a unipolar battery module.

[0105] (c) Workpiece configuration

[0106] This manufacturing method includes placing a workpiece 201 within a chamber 110. For example, a workpiece 201 after liquid injection can be placed within a chamber 110 (see reference). Figure 4 ).

[0107] (d) Connection to return piping

[0108] This manufacturing method includes connecting the outer casing 210 and the first opening 141 (return pipe 140) (see reference). Figure 4 For example, the liquid injection port 241 and the first opening 141 can be connected. In the case of the battery module 250, each independent return pipe 140 can be connected to the liquid injection port 241 of each battery 200. In addition to the liquid injection port 241, a gas vent (not shown) can be provided on the outer casing 210. The gas vent can function as a gas flow path.

[0109] (e) Decompression

[0110] This manufacturing method includes depressurizing the external assembly 210 via the return piping 140 by depressurizing the chamber 110 (see reference). Figure 4 Pressure can be reduced within chamber 110 via pressure reducing device 130. Pressure loss occurs within return piping 140.

[0111] The completion of pressure reduction can be determined, for example, by the indication value of pressure gauge 150. For example, the target pressure reduction can be determined when the indication value of pressure gauge 150 is below the reference value. That is, pressure reduction in the external body 210 can be achieved by the indication value of pressure gauge 150 falling below the reference value.

[0112] The completion of pressure reduction can be determined, for example, by the flow meter 160. For instance, after the pressure reducing device 130 stops, if the cumulative value of the measurement on the flow meter 160 (the total amount of gas discharged) is above a reference value, it can be determined that the target pressure reduction has been achieved. If the target pressure reduction has not been achieved, the pressure reducing device 130 can be restarted.

[0113] The baseline values ​​for pressure and flow rate can be appropriately set according to the target pressure reduction, the shape of pipe 143, etc. The target pressure reduction can be, for example, 5 to 50 kPa.

[0114] (f) Sealing

[0115] This manufacturing method may include sealing the outer casing 210 under reduced pressure. This seals the battery module 250. The battery module 250 includes a plurality of batteries 200. For example, the filling port 241 may be sealed by a sealing device 120 within the chamber 110. For example, the sealing material 240 may be melted and solidified by hot pressing. The filling port 241 may be sealed by the sealing material 240 (see reference). Figure 7 Blockage. For example, the injection port 241 can be blocked outside the chamber 110.

[0116] experiment

[0117] In this experiment, a battery module 250 is prepared as workpiece 201. The battery module 250 is bipolar. The battery module 250 contains 5 batteries 200.

[0118] Example

[0119] In this embodiment, the manufacturing apparatus 100 (see reference) is used. Figure 4 Each independent return piping 140 is connected to one of the five batteries 200. Pressure is applied to the outer casing 210 via the return piping 140 by depressurizing the chamber 110. The outer casing 210 is then sealed at the target pressure level. The achievement of the target pressure level is determined by using a pressure gauge 150 and a flow meter 160 in combination.

[0120] Comparative example

[0121] Figure 9 This is a concept map representing comparative examples.

[0122] In the comparative example, the battery module 250 is disposed within the chamber 310. Depressurization is achieved by depressurizing the chamber 310, thereby depressurizing the outer casing 210. By depressurizing the chamber 310, all five batteries 200 are simultaneously depressurized. After depressurization, the outer casing 210 is sealed. The depressurization time is the same as in the embodiment. Furthermore, for example, it is also possible to install an additional pressure gauge at the vent 311 of the chamber 310 to determine whether the target depressurization level has been reached.

[0123] evaluate

[0124] In each of the five batteries 200, the gas flow path was visually checked for blockages. If expansion due to residual gas was observed in a single battery 200, the gas flow path was considered blocked. If no expansion due to residual gas was observed in a battery 200, the gas flow path was considered unblocked.

[0125] In this embodiment, no gas flow path blockage was identified. In this embodiment, it is assumed that internal pressure can be maintained for all batteries.

[0126] In the comparative example, a blockage in the gas flow path was confirmed. In the comparative example, it was determined that the internal pressure could not be guaranteed for all batteries.

[0127] This embodiment and this example are illustrative in all respects. This embodiment and this example are not restrictive. The scope of this disclosure includes all modifications within the meaning and scope equivalent to the description in the patent claim. For example, it includes from the outset the possibility of extracting arbitrary structures from this embodiment and this example and combining them arbitrarily.

Claims

1. A manufacturing apparatus for manufacturing an electrochemical cell in which an outer case is reduced in pressure, the manufacturing apparatus characterized by comprising: a chamber, a pressure reducing device, and a return pipe, the pressure reducing device being configured to reduce the pressure in the chamber, the return pipe comprising a first opening portion, a pipe, and a second opening portion, the first opening portion and the second opening portion each independently opening in the chamber, the first opening portion being configured to be connected to the outer case, the pipe connecting the first opening portion and the second opening portion, the pipe being configured to temporarily discharge gas in the outer case to the outside of the chamber and then return the gas to the chamber when the chamber has been reduced in pressure.

2. The manufacturing apparatus according to claim 1, characterized in that the return pipe comprises a plurality of return pipes that are independent of each other, and each of the plurality of return pipes comprises the first opening portion, the pipe, and the second opening portion.

3. The manufacturing apparatus according to claim 1 or 2, characterized by further comprising a pressure gauge, the pressure gauge being connected to the pipe.

4. The manufacturing apparatus according to claim 1 or 2, characterized by further comprising a flow meter, the flow meter being connected to the pipe.

5. The manufacturing apparatus according to claim 1 or 2, characterized by further comprising a sealing device, the sealing device being configured to seal the outer case in the chamber. including the following steps: preparing the manufacturing apparatus according to any one of claims 1 to 5; preparing a workpiece by housing a power generating element in the outer case; arranging the workpiece in the chamber; connecting the outer case and the first opening portion; and reducing the pressure in the outer case by reducing the pressure in the chamber via the return pipe.

7. The manufacturing method according to claim 6, characterized in that in the step of preparing the manufacturing apparatus, the manufacturing apparatus comprising a plurality of return pipes that are independent of each other is prepared, in the step of preparing the workpiece, a battery module comprising a plurality of electrochemical cells is prepared as the workpiece, each of the plurality of electrochemical cells independently comprises an internal space, and in the step of connecting the outer case and the first opening portion, each of the plurality of internal spaces is connected to the return pipe.

8. The manufacturing method according to claim 6 or 7, characterized in that in the step of preparing the manufacturing apparatus, the manufacturing apparatus comprising a pressure gauge is prepared, and in the step of reducing the pressure in the outer case, the pressure in the outer case is reduced in such a manner that an indicated value of the pressure gauge becomes below a reference value.

9. The manufacturing method according to claim 6 or 7, characterized in that in the step of preparing the manufacturing apparatus, the manufacturing apparatus comprising a flow meter is prepared, and in the step of reducing the pressure in the outer case, the pressure in the outer case is reduced in such a manner that an accumulated value of a measured value of the flow meter after the pressure reduction is stopped becomes above a reference value.

10. The manufacturing method according to claim 6 or 7, characterized in that ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6. A method of manufacturing an electrochemical cell, characterized by, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Further comprising forming a liquid injection port on the exterior body, and injecting an electrolyte into the exterior body from the liquid injection port, In a step of connecting the exterior body and the first opening portion, the first opening portion of the return flow pipe is connected to the liquid injection port.

11. The manufacturing method according to claim 6 or 7, wherein The exterior body includes at least one selected from a metal foil and a metal foil laminate film.

12. The manufacturing method according to claim 7, wherein In a step of preparing the workpiece, a bipolar battery module is prepared as the workpiece.

13. The manufacturing method according to claim 6 or 7, wherein Further comprising sealing the exterior body in a reduced pressure state.

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