Secondary battery and control method of the secondary battery

Abstract

To provide a secondary battery capable of generating a restraining force inside an exterior member formed of a laminate film and a control method of the secondary battery.SOLUTION: A secondary battery 10 includes an exterior member 30 whose a peripheral edge is sealed in a state in which a laminate film is stacked and which has a sealed space S therein, an electrode module 20 housed in the sealed space S, and a port part 50 capable of opening and closing the sealed space S. The port part 50 includes a bag-shaped seal part 52 in which the peripheral edge excluding a part thereof is sealed, and a metal pipe 56 in which one end part 56A is disposed outside the seal part 52 and communicates with the inside of the sealed space S, the other end part 56B is disposed inside the seal part 52, and at least a part of an outer peripheral surface of the other end part 56B is fixed by a second laminate film on the peripheral edge of the seal part 52 via a second sealant film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a secondary battery and a method for controlling the secondary battery. [Background technology]

[0002] Patent Document 1 listed below discloses an overvoltage detection method for detecting contact pressure on at least one stacking surface between laminate-cased batteries in a stack formed by stacking multiple laminate-cased batteries in the thickness direction, or contact pressure on the abutment surface between the stack and a holding member that holds the stack, and determining that an overvoltage has occurred if the contact pressure exceeds a predetermined threshold. Furthermore, Patent Documents 2 to 4 listed below disclose structures in which a port is provided for venting internal gas in a battery housed in a laminate exterior. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-269345 [Patent Document 2] Patent No. 7040294 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-31934 [Patent Document 4] Special Publication No. 2023-529685 Summary of the Invention [Problem to be solved by the invention]

[0004] By reducing the pressure inside the laminated outer casing, a confining pressure can be applied to the electrode module inside the laminated outer casing due to the pressure difference between the atmospheric pressure inside the laminated outer casing and the outside. However, due to deterioration of the laminated outer casing over time, etc., oxygen or nitrogen may enter the inside of the laminated outer casing in a market environment. If oxygen or nitrogen enters the inside of the laminated outer casing, the pressure inside the laminated outer casing may increase, and the confining pressure may become insufficient.

[0005] In consideration of the above, an object of the present invention is to provide a secondary battery capable of generating a restraining force inside an exterior member formed of a laminate film, and a method for controlling the secondary battery. [Means for solving the problem]

[0006] The secondary battery of the present invention described in claim 1 comprises an exterior member whose periphery is sealed with laminate films superimposed thereon and which has an enclosed space inside, an electrode module housed in the enclosed space, and a port section provided on at least a part of the periphery, which communicates with the enclosed space and can open and close the enclosed space, wherein the port section has one end which has an inlet for air to flow in and which communicates with the enclosed space, and the other end which has an outlet for discharging air and is arranged outside the enclosed space, and comprises a valve section which can open and close an air passage from the inlet to the outlet.

[0007] Here, in the present invention, the term "sealed space" does not only refer to a space that is strictly sealed, but also includes a space that is closed but in which some air or the like flows in and out due to, for example, deterioration of an exterior member over time.

[0008] In the secondary battery according to the first aspect of the present invention, a port portion is provided in at least a portion of the periphery of the laminate film, which is sealed in a stacked state, and which communicates with the sealed space inside the exterior member and can open and close the sealed space. The port portion also has one end having an inlet that communicates with the sealed space, and the other end having an outlet that is disposed outside the sealed space, and is provided with a valve portion that can open and close an air passage from the inlet to the outlet. Therefore, by opening the air passage with the valve portion, air within the sealed space can flow in through the inlet and be discharged through the outlet. This reduces the pressure within the sealed space, thereby generating a restraining force inside the exterior member formed of the laminate film.

[0009] The secondary battery of the present invention described in claim 2 has the configuration described in claim 1, wherein the valve portion has a flat portion at one end, and the front and back surfaces of the flat portion are fixed to the laminate film on the periphery via a sealant film.

[0010] In the secondary battery of the present invention described in claim 2, the front and back surfaces of the flat portion provided at one end having an inlet are fixed with a laminate film via a sealant film, thereby improving sealing properties compared to when the cylindrical outer surface is fixed with a laminate film.

[0011] The secondary battery of the present invention described in claim 3 comprises an exterior member whose periphery is sealed when laminate films are overlapped and which has an enclosed space inside, an electrode module housed in the enclosed space, and a port portion provided on at least a part of the periphery, which communicates with the enclosed space and can open and close the enclosed space, and the port portion comprises a bag-shaped seal portion whose periphery except for a part is sealed when a second laminate film is overlapped, and a metal pipe whose one end is arranged outside the seal portion and communicates with the enclosed space, and whose other end other than the one end is arranged within the seal portion, and at least a part of the outer peripheral surface of the other end is fixed to the second laminate film on the periphery of the seal portion via a second sealant film.

[0012] In a secondary battery according to the present invention, the sealed portion is formed in a bag shape, one end of the metal pipe is connected to the sealed space, and the other end is disposed within the sealed portion. At least a portion of the outer periphery of the other end is fixed to a second laminate film around the periphery of the sealed portion via a second sealant film. This allows air within the sealed space to flow in through one end of the metal pipe, be discharged from the other end of the metal pipe into the bag-shaped sealed portion, and be discharged to the outside through the unsealed portion of the periphery of the sealed portion. This reduces the pressure within the sealed space, generating a restraining force within the exterior member formed of the laminate film.

[0013] The secondary battery of the present invention described in claim 4 has the configuration described in claim 3, wherein the sealing portion has an opening on the peripheral edge of the portion, and the opening can be closed, and a second opening can be formed by cutting out the closed opening.

[0014] In the secondary battery according to the present invention, the sealing portion has an opening on the periphery of the part. The opening can be closed, and a second opening can be formed by cutting away the closed opening. This allows the interior of the sealing portion to be opened and closed.

[0015] A control method for a secondary battery according to the present invention, as set forth in claim 5, measures the internal pressure in the sealed space of a secondary battery as set forth in any one of claims 1 to 4, and reduces the pressure in the sealed space by the port portion when the measured internal pressure is equal to or greater than a predetermined threshold value.

[0016] In the control method for a secondary battery according to the present invention as set forth in claim 5, when the internal pressure in the sealed space is equal to or greater than a predetermined threshold, a warning is issued to request the sealed space to be depressurized by the port unit, so that the user can recognize the need to depressurize the sealed space. By the user recognizing the need to depressurize, the port unit can reduce the pressure in the sealed space, so that a restraining force can be generated inside the exterior member formed of the laminate film. [Effects of the Invention]

[0017] As described above, the secondary battery and the method for controlling the secondary battery according to the present invention have the excellent effect of being able to generate a restraining force inside an exterior member formed of a laminate film. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a cross-sectional view in a stacking direction of a secondary battery according to an embodiment of the present invention. [Figure 2] 2 is an explanatory view illustrating a molding process of an exterior member of the secondary battery of FIG. 1. FIG. [Figure 3] 1. FIG. 4 is an explanatory view illustrating a process of assembling an exterior member of the secondary battery of FIG. [Figure 4] 10A to 10C are explanatory diagrams illustrating a molding process and a method of using the port portion. [Figure 5] 3 is a flowchart illustrating a method for controlling a secondary battery according to an embodiment of the present invention. [Figure 6] FIG. 10 is an explanatory diagram for explaining the amount of air entering the exterior member. [Figure 7] 10A to 10C are explanatory views illustrating a molding process and a method of using a port portion according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, a secondary battery 10 according to a first embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, the same or equivalent elements are denoted by the same reference numerals, and duplicated descriptions will be omitted. In addition, duplicated reference numerals may be omitted as appropriate in the drawings. In addition, in FIG. 1, the thickness and thickness ratio of each component are exaggerated for ease of explanation and may differ from the actual thickness.

[0020] The secondary battery 10 of this embodiment is, for example, a bipolar secondary battery, and is used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The secondary battery 10 is, for example, a nickel-metal hydride secondary battery or a lithium-ion secondary battery. The secondary battery 10 may also be, for example, an electric double layer capacitor.

[0021] 1, the secondary battery 10 includes an electrode module 20 and an exterior member 30 arranged to encase the electrode module 20. The electrode module 20 includes an electrode stack 21 formed by stacking a plurality of bipolar electrodes 22 with separators 24 interposed therebetween, and a seal portion 40 arranged to surround the electrode stack 21. In this embodiment, as an example, the electrode module 20 has a rectangular shape when viewed from the stacking direction (see FIG. 3).

[0022] The bipolar electrode 22 is configured by bonding and integrating a positive electrode layer 27 and a negative electrode layer 28 to both sides of a rectangular sheet-shaped current collector 26. In the electrode laminate 21 of this embodiment, current collectors 26 are laminated at both ends (ends) in the lamination direction D, and these end-most current collectors 26 are referred to as end current collectors 26A.

[0023] The seal portion 40 is made of, for example, an insulating resin, and is formed in a frame shape on the peripheral edge of the electrode stack 21 so as to surround the electrode stack 21, and includes a pair of holding seal materials 42, a peripheral holding seal portion 44, and a spacer 46. The pair of holding seal materials 42 are bonded to the peripheral edge of the upper or lower surface of each current collector 26, respectively, and hold each current collector 26 from both sides in the stacking direction D.

[0024] Furthermore, a cover member 16, which will be described later, is disposed on the outside of each of the seal portions 40 on the short sides of the electrode stack 21.

[0025] In this embodiment, a plurality of spaces are provided within the electrode module 20, and each space is airtightly and liquidtightly sealed by a seal portion 40. Each space contains an electrolyte solution (not shown) containing, for example, a nonaqueous solvent and a supporting salt. The electrolyte solution is impregnated into the separator 24, the positive electrode layer 27, and the negative electrode layer 28.

[0026] The exterior member 30 is arranged to encase the electrode module 20, and is composed of a pair of exterior bodies 31 made of laminate films formed by overlapping film materials. In this embodiment, the exterior member 30, i.e., the exterior bodies 31, is composed of, for example, an aluminum laminate film. Here, an example of a molding method for the exterior body 31 will be described. Note that in the cross-sectional views of each process along line AA in FIG. 2, the double-sided laminate film 36 and the highly molded laminate film 37 are depicted as components made of a single film, but in reality, they are laminate films in which multiple films are stacked.

[0027] As shown in FIG. 2(A), first, an aluminum foil 32 having a thickness t of 0.1 mm and a rectangular shape in a plan view is placed as an example of a conductive metal layer. Next, as shown in FIG. 2(B), a sealant film 34 is disposed around the periphery of the aluminum foil 32 to provide heat-sealing. For example, the sealant film 34 is formed by laminating, from the aluminum foil 32 side, a 25 μm PPa (acid-modified polypropylene) layer, a 50 μm PP (polypropylene) layer, and a 25 μm PPa layer, resulting in a thickness of 100 μm. The sealant film 34 also includes strip-shaped frame portions 34A disposed on each of the four sides of the aluminum foil 32, and protruding portions 34B disposed on both long sides of the aluminum foil 32 so as to protrude from the aluminum foil 32 with a gap therebetween. The protruding portion 34B is disposed so that one end overlaps a part of the frame portion 34A, and the other end protrudes in the shorter direction of the aluminum foil 32.

[0028] Next, as shown in FIG. 2(C), a double-sided laminate film 36 is disposed so as to overlap two adjacent protrusions 34B in the longitudinal direction of the aluminum foil 32. The double-sided laminate film 36 is formed in a rectangular shape, has adhesive layers attached to both sides, and is disposed so that its longitudinal direction is located inside the adjacent protrusions 34B. Furthermore, as an example, the double-sided laminate film 36 is disposed so that its inner end in the short direction is located inside the protrusions 34B and its outer end is approximately aligned with the outer end of the protrusions 34B. As an example, the double-sided laminate film 36 is formed by laminating, from the aluminum foil 32 side, a 70 μm thick PP layer, a 40 μm thick aluminum layer, and a 70 μm thick PP layer, and has a thickness of 180 μm.

[0029] Next, as shown in FIG. 2(D), two highly molded laminate films 37, each formed in a roughly U-shape with a recess at one end of the rectangular shape, are arranged facing each other with a gap in the longitudinal direction of the aluminum foil 32. The highly molded laminate films 37 are arranged so that the inner edge of the recessed portion is located slightly outward of the inner edge of the frame portion 34A. The highly molded laminate films 37 are also arranged so that the closest opposing edge overlaps the protruding portion 34B. For example, the highly molded laminate film 37 is formed by stacking, from the aluminum foil 32 side, a 30 μm PP layer, a 30 μm PPa layer, an 80 μm aluminum layer, a 25 μm Ny (nylon) layer, an approximately 1.5 μm adhesive layer, and a 12 μm PET (polyethylene terephthalate) layer, resulting in a thickness of approximately 178.5 μm.

[0030] In addition, four strip-shaped insulating films 38 are arranged across the boundary between the highly molded laminate film 37 and the sealant film 34 (see FIG. 2(B)). The insulating films 38 are made of the same material as the sealant film 34 described above.

[0031] 2(E), the laminate film thus stacked is embossed along the dotted line indicated by the arrow 39 in an embossing step to form a recess 30A in the center and a flange 30B on the outer periphery. This flange 30B corresponds to the "periphery" of the present invention and serves as a seal when a pair of exterior bodies 31 are attached with the electrode module 20 enclosed therein.

[0032] The pair of exterior bodies 31 thus formed are subjected to a spike leak test.

[0033] Next, the assembly process of the exterior member 30 will be described. Note that in Figures 3(C) and 3(D), a port section 50, which will be described later, is shown schematically. Also, the electrode module 20 shown in Figure 3(A) has already undergone a reduced pressure sealing process and a self-discharge test.

[0034] As shown in FIG. 3(A), the electrode module 20 is formed in a substantially rectangular parallelepiped shape and includes a liquid filling port frame 12 having a liquid filling port (not shown) through which an electrolyte solution (described later) is filled, and a substrate 14 for detecting the voltage of each bipolar electrode 22 constituting the secondary battery 10. The substrate 14 includes an FPC (Flexible Printed Circuits) board 14A, which is an example of a voltage detection circuit board including a circuit for detecting voltage. Both ends of the FPC board 14A are held by an FPC housing 14B. Also, in FIG. 3, an end current collector 26A is exposed at the center of the vertical end face of the electrode stack 21. The FPC board 14A is subjected to a known sealing process required for sealing with the PP layer on the recess 30A side of the flange 30B of the exterior body 31. In this embodiment, the side on which the substrate 14 is provided will be referred to as the "reference short side," and the side opposite the reference short side will be referred to as the "anti-reference short side."

[0035] Next, as shown in FIG. 3(B), hollow cover members 16 are disposed on the reference short side and the counter-reference short side of the electrode module 20, respectively.

[0036] 3(C), a pair of exterior bodies 31 are assembled from both sides of the electrode module 20 on which the cover member 16 is disposed so as to enclose the electrode module 20. An enclosed space S is formed inside the assembled pair of exterior bodies 31. When assembling the pair of exterior bodies 31, a port portion 50 (described later) is disposed between the opposing flange portions 30B of the pair of exterior bodies 31.

[0037] Next, as shown in Fig. 3(D), the flange portions 30B of the pair of exterior bodies 31 are overlapped and joined together. At this time, as shown in Fig. 3, the flange portions 30B are positioned on the FPC board 14A. Furthermore, as described above, the port portion 50 is disposed so as to be positioned between the flange portions 30B of the pair of exterior bodies 31. In the present embodiment, as an example, the port portion 50 is disposed at a position that does not overlap with the FPC board 14A on the reference short side, and more specifically, the port portion 50 is disposed so that a portion of the port portion 50 communicates with the interior of the sealed space S formed by the opposing recesses 30A.

[0038] In this embodiment, the opposing surfaces of the flange portions 30B of the pair of exterior bodies 31 are made of PP layers, and the PP layers are joined together by heat welding, for example.

[0039] Next, the port portion 50 will be described. In Figures 4(A) and 4(B), the lower diagram is a cross-sectional view taken along line BB in the upper diagram. As shown in Figure 4(A), the port portion 50 includes a bag-shaped seal portion 52 and a cylindrical metal pipe 56. The seal portion 52 is formed by overlapping, for example, rectangular laminate films 52A and 52B, and the periphery except for one side is sealed. Specifically, for example, the periphery is sealed by heat welding the shaded area W in the upper diagram of Figure 4(A). An opening 54 is formed in the periphery of the seal portion 52 on the unsealed side.

[0040] Furthermore, the opposing laminate films 52A and 52B that make up the seal portion 52 are formed by laminating, in order from the opposing side, a 30 μm PP layer, an 80 μm aluminum layer, and a 30 μm PP layer, each having a thickness of approximately 140 μm. The pair of laminate films 52A and 52B may be the same as those used for the exterior body 31. The seal portion 52 may be formed by heat welding the periphery of a single laminate film in a folded state.

[0041] 4(A), as an example, one end 56A of the metal pipe 56 on the left side of the drawing is disposed outside the seal portion 52, and the one end 56A is disposed so as to communicate with the inside of the sealed space S. The other end 56B of the metal pipe 56 other than the one end 56A is disposed inside the seal portion 52. In other words, the other end 56B of the metal pipe 56 is disposed between the overlapping laminate films that form the seal portion 52.

[0042] The other end 56B of the metal pipe 56 is fixed to the periphery of the sealed portion 52 at a portion adjacent to the one end 56A via a sealant film 57, the outer surface of which is made of a PPa layer. Specifically, region W corresponds to the adjacent portion, and when the periphery of the laminate film is heat-sealed at the sealed portion 52, the adjacent portion of the periphery is also heat-sealed.

[0043] Port portion 50 formed in this manner is fixed to exterior member 30 by heat welding, for example, the area indicated by the shaded area 58 in FIG. 4(B) between flange portions 30B of the pair of exterior bodies 31. At this time, one end portion 56A is inserted into cover member 16 through insertion hole 16A provided in cover member 16 and communicates with the interior of sealed space S. In addition, when port portion 50 is fixed to exterior member 30, it has opening 54 on the side not fixed.

[0044] Next, the decompression process will be described. As shown in the upper diagram of FIG. 4(C), the opening 54 of the seal portion 52 is evacuated from the opening 54 using, for example, an impulse sealer 60, and then sealed. The exhaust from the opening 54 is performed, for example, by sealing the position corresponding to the other end 56B of the metal pipe 56 with a sealing member 62 from above the laminate film constituting the seal portion 52, using an evacuation box 64 with the opening 54 side open. After the exhaust from the opening 54, the opening 54 of the seal portion 52 is closed by heat-sealing the end on the opening 54 side with the impulse sealer 60. Then, as shown in the lower diagram of FIG. 4(C), the impulse sealer 60, the sealing member 62, and the evacuation box 64 are removed, and the sealed space S is decompressed and sealed. The secondary battery 10 is formed by decompressing and sealing the port portion 50 in this manner.

[0045] Next, re-decompression sealing will be described. As the secondary battery 10 formed as described above is used, there is a possibility that oxygen or nitrogen may enter the interior of the exterior member 30 in a market environment due to aging deterioration of the exterior member 30. If oxygen or nitrogen enters the interior of the exterior member 30, the internal pressure of the sealed space S may increase. In this embodiment, in such a case, re-decompression sealing can be performed, in which the internal pressure of the sealed space S is reduced again and the sealed space S is sealed.

[0046] As shown in FIG. 4(D), the closed opening 54 is opened by being cut off with a blade 70, and a new second opening 55 is formed in the sealed portion 52. This second opening 55 is sealed after evacuating the second opening 55 with an impulse sealer 60, similar to the decompression step shown in FIG. 4(C) described above. This allows for re-decompression sealing. After re-decompression sealing, as shown in the lower diagram of FIG. 4(D), the sealed second opening 55 has a shorter remaining width than the first opening 54 by the amount that has been cut off.

[0047] Next, a method for controlling the secondary battery 10 configured as described above will be described. In this embodiment, as an example, the secondary battery 10 is controlled by an ECU (Electronic Control Unit; not shown) provided in a vehicle (not shown) in which the secondary battery 10 is mounted. As shown in FIG. 5, first, in step S11, the ECU logs the internal pressure in the sealed space S. Here, the internal pressure in the sealed space S is measured, as an example, by disposing an internal pressure sensor P (see FIG. 1) in advance in the sealed space S and acquiring an output from this internal pressure sensor P. Specifically, a signal is extracted from a welded portion of a laminate film on the FPC board 14A.

[0048] Furthermore, the internal pressure in the sealed space S may be estimated by, for example, deriving the amount of air that has entered the exterior member 30. In this case, as shown in FIG. 6, the length of the laminate film that forms the pair of exterior bodies 31 at the position where the port portion 50 is disposed is defined as the permeable seal length L through which air passes (see FIG. 1). Furthermore, the cross-sectional area of ​​the plane perpendicular to the permeable seal length L of the pair of exterior bodies 31 is defined as the cross-sectional area D through which air passes, and the air pressure in the sealed space is defined as P IN , the external pressure is P OUT Furthermore, let α be the air permeability of the resin (laminate film), T be the temperature of the resin (laminate film), and Q be the amount of air that permeates the resin (laminate film) per unit time. Then, the following equation (1) holds true.

[0049] Q=(P OUT -P IN )×D / L×α ∝ P OUT ×T···(1)

[0050] Here, the external pressure P OUT is assumed to be a constant value, 0 kPa. Also, the permeable seal length L is assumed to be constant, although there may be slight differences in length due to manufacturing variations, etc. Furthermore, the air permeability α of the resin depends on the temperature T of the resin.

[0051] External air pressure P OUTThe internal pressure may be estimated by measuring the resin temperature T and the resin temperature, and deriving the amount of air Q that has entered based on these values ​​and the above formula (1).

[0052] Next, in step S12, the ECU determines whether the internal pressure value acquired in step S11 is equal to or greater than a first threshold value. Here, the first threshold value is a preset threshold value, which is a warning reference value at which the internal pressure in the sealed space S needs to be reduced to the above-mentioned re-decompression sealing.

[0053] If the internal pressure value is equal to or greater than the first threshold value in step S12 (step S12; YES), the ECU issues a warning in step S13. The warning may be issued by, for example, issuing a warning sound from a speaker provided in the vehicle, or by displaying, for example, a message on a display screen provided in the vehicle saying "Please re-depressurize the secondary battery."

[0054] On the other hand, if the value of the internal pressure is smaller than the first threshold value in step S12 (step S12; NO), the ECU shifts the process to step S11 and continues the process from step S11 onwards.

[0055] Next, in step S14, the ECU determines whether re-depressurization has been performed. As an example, the determination of whether re-depressurization has been performed may be performed by having an operator or the like input a signal to the ECU indicating that re-depressurization has been completed when re-depressurization has been performed, and the ECU determines whether this signal has been input. That is, the processing of step S14 is performed after a predetermined time has elapsed since the warning was issued in step S13. If re-depressurization has been performed (step S14; YES), the ECU proceeds to step S11 and continues the processing from step S11 onwards.

[0056] On the other hand, if re-pressurization has not been performed (step S14; NO), in step S15 the ECU determines whether the current internal pressure value is equal to or greater than a second threshold value. Here, the second threshold value is a preset threshold value, which is a reference value at which the internal pressure in the enclosed space S may become damaged or the like. In step S15, if the internal pressure value is equal to or greater than the second threshold value (step S15; YES), in step S16 the ECU stops the vehicle and ends all processing.

[0057] On the other hand, if the internal pressure value is smaller than the second threshold value in step S15 (step S15; NO), the ECU shifts the process to step S13, issues a warning again, and continues the process from step S14 onwards.

[0058] Next, the effects of the secondary battery 10 in the first embodiment will be described.

[0059] In the secondary battery 10 according to this embodiment, a port 50 that communicates with the sealed space S inside the exterior member 30 and can open and close the sealed space S is provided on at least a part of the periphery that is sealed with the laminate films stacked together. Therefore, by opening the sealed space S with the port 50, the air inside the sealed space S can be discharged. This reduces the pressure inside the sealed space S, and a restraining force can be generated inside the exterior member 30 formed of the laminate film.

[0060] In the secondary battery 10 according to this embodiment, the sealed portion 52 is formed in a bag shape, and one end 56A of a metal pipe 56 is in communication with the sealed space S, and the other end 56B is disposed within the sealed portion 52. At least a portion of the outer peripheral surface of the other end 56B is fixed to a laminate film on the periphery of the sealed portion 52 via a sealant film 57. This allows air within the sealed space S to flow in from the one end 56A of the metal pipe 56, be discharged from the other end 56B of the metal pipe 56 into the bag-shaped sealed portion 52, and be discharged to the outside from the unsealed portion of the periphery of the sealed portion 52.

[0061] Furthermore, in the secondary battery 10 according to this embodiment, the seal portion 52 has an opening 54 on the periphery of the part. The opening 54 can be closed, and a second opening 55 can be formed by cutting out the closed opening 54. This allows the interior of the seal portion 52 to be opened and closed.

[0062] Furthermore, in the control method for secondary battery 10 according to this embodiment, when the internal pressure in sealed space S is equal to or greater than a predetermined first threshold, a warning is issued by port unit 50 to reduce the pressure in sealed space S, allowing the user to recognize the need to reduce the pressure in sealed space S. By the user recognizing the need to reduce the pressure, port unit 50 can reduce the pressure in sealed space S, thereby generating a restraining force inside exterior member 30 formed of a laminate film.

[0063] A secondary battery 10A according to a second embodiment of the present invention will now be described with reference to the drawings. The secondary battery 10A of this embodiment includes a port unit 80 having a different configuration from the port unit 50 of the first embodiment described above. Note that in this embodiment, the configuration other than the port unit is the same as that of the secondary battery 10 of the first embodiment described above, so only the port unit 80 will be described in detail here.

[0064] As shown in FIG. 7(A), the port portion 80 includes a valve portion 82. The valve portion 82 has a flat portion 84A at one end 84 formed of a metal pipe on the exterior member 30 side, and the end of the flat portion 84A has an inlet 85 through which air flows in. The inlet 85 of the one end 84 communicates with the sealed space S. Specifically, as shown in FIG. 7(B), the one end 84 is positioned so that the inlet 85 faces the insertion hole 16A of the cover member 16. The front and back surfaces of the flat portion 84A (the upper and lower surfaces in FIG. 7(A)) are heat-welded between the laminate films of the flange portions 30B of the pair of exterior bodies 31 via sealant films 84B, and are fixed to the exterior member 30.

[0065] The valve section 82 also includes a substantially cylindrical valve body 87 and a valve core 88 at its other outer end 86. The valve body 87 includes an internal air passage 87A that communicates with the inlet 85 at one end 84. The valve core 88 also includes a spring member 88A that is axially movable through the air passage 87A of the valve body 87. The spring member 88A is biased outward by the internal pressure of the sealed space S, and this biasing force causes a seal member 88B provided on the valve core 88 to close the air passage 87A. In this embodiment, as an example, the outer end of the valve body 87 serves as an outlet 89 through which air is discharged.

[0066] Next, the decompression step will be described. As shown in the upper diagram of Figure 7(C), an exhaust valve 90 is attached to the outer side of the valve body 87. The exhaust valve 90 is formed in a cylindrical shape with an internal space 92, and has an exhaust hole 94 on the outer side that communicates with the space 92. The exhaust valve 90 is attached to the other end of the valve body 87 by screwing. This attachment causes the pressure in the space 92 to become higher than the pressure in the ventilation path 87A, thereby weakening the biasing force of the spring member 88A. When the biasing force of the spring member 88A weakens, the valve core 88 moves toward the exterior member 30, and the seal member 88B opens the ventilation path 87A.

[0067] When the ventilation path 87A is opened, the air inside the sealed space S is discharged from the exhaust port 89 and then through the exhaust hole 94 to the outside, as shown in the upper diagram of Figure 7(C). After the desired internal pressure is reached inside the sealed space S, as shown in the middle diagram of Figure 7(C), when the exhaust valve 90 is removed, the spring member 88A is again urged outward by the internal pressure of the sealed space S, and this urging force causes the seal member 88B provided on the valve core 88 to close the ventilation path 87A.

[0068] As shown in the lower diagram of FIG. 7(C), the cap 100 is attached to the outer side of the valve body 87 with the ventilation path 87A closed. The cap 100 is formed, for example, from a metal member and includes a metal cap 110 and a metal seal 120. The metal cap 110 is formed in a circular box shape with a bottom, and the open side is attached to the valve body 87 by screwing. A metal seal is interposed between the metal cap 110 and the valve body 87. Note that in this embodiment, for example, the port unit 80 is attached to the exterior member 30 with the cap 100 attached to the valve body 87, as shown in the lower diagram of FIG. 7(C), and the secondary battery 10A is completed with the port unit 80 attached in this manner.

[0069] Next, re-vacuum sealing will be described. In this embodiment, by removing the cap 100 and re-attaching the exhaust valve 90 to the outside of the valve body 87 as shown in the upper diagram of Figure 7(C), the inside of the sealed space S can be depressurized again by the above-mentioned action. After depressurization, the exhaust valve 90 is removed from the valve body 87 and the cap 100 is attached to the valve body 87, thereby performing re-vacuum sealing.

[0070] Next, the effects of the secondary battery 10A in the second embodiment will be described.

[0071] In the secondary battery 10A according to this embodiment, the port unit 80 has one end 84 having an inlet 85 that communicates with the inside of the sealed space S, and the other end 86 having an outlet 89 that is disposed outside the sealed space S. The port unit 80 also includes a valve unit 82 that can open and close an air passage 87A from the inlet 85 to the outlet 89. Therefore, by opening the air passage 87A with the valve unit 82, air within the sealed space S can flow in through the inlet 85 and be discharged through the outlet 89.

[0072] In the secondary battery 10A according to this embodiment, the front and back surfaces of the flat portion 84A provided at the one end portion 84 having the inlet 85 are fixed with a laminate film via a sealant film 84B. Therefore, the sealing property can be improved compared to when the cylindrical outer peripheral surface is fixed with a laminate film.

[0073] Furthermore, in the secondary battery 10A according to this embodiment, the cap 100 is attached to the valve body 87, so that air leakage from the exhaust port 89 can be suppressed.

[0074] [supplementary explanation] In the above-described embodiment, the electrode module 20 includes the electrode stack 21 in which a plurality of bipolar electrodes 22 are stacked, but the present invention is not limited to this. The electrode module 20 may also include a general electrode stack that does not include the bipolar electrodes 22, i.e., an electrode stack in which a plurality of cells are stacked.

[0075] In the second embodiment described above, the valve unit 82 has the above-described configuration, but the present invention is not limited to this. The valve unit 82 may have any configuration as long as it is capable of discharging air, and known technology can be used.

[0076] Furthermore, in the above-described embodiment, the laminate film and sealant film that constitute the exterior member 30 and the seal portion 52 have the above-described configurations, but the present invention is not limited to this, and the materials can be changed as appropriate.

[0077] Furthermore, the configuration of the present disclosure is not limited to the above-described embodiment, and the configuration can be modified as appropriate as long as the problem can be solved. [Explanation of symbols]

[0078] 10, 10A secondary battery, 20 electrode module, 30 exterior member, 50, 80 port portion, 52 seal portion, 54 opening, 55 second opening, 56 metal pipe, 56A one end, 56B other end, 84 one end, 84A flat portion, 84B sealant film, 85 inlet, 86 other end, 87 ventilation channel, 89 Discharge port, S closed space

Claims

1. an exterior member having a sealed space therein, the edges of which are sealed in a state in which the laminate films are overlapped; an electrode module accommodated in the sealed space; a port portion provided on at least a part of the periphery, communicating with the sealed space, and capable of opening and closing the sealed space; The port portion has one end having an inlet through which air flows in, which is connected to the inside of the sealed space, and the other end having an outlet through which air is discharged, which is arranged outside the sealed space, and is equipped with a valve portion that can open and close the air passage from the inlet to the outlet.

2. 2. The secondary battery according to claim 1, wherein the valve portion has a flat portion at one end, and the front and back surfaces of the flat portion are fixed to the laminate film on the periphery via a sealant film.

3. an exterior member having a sealed space therein, the edges of which are sealed in a state in which the laminate films are overlapped; an electrode module accommodated in the sealed space; a port portion provided on at least a part of the periphery, communicating with the sealed space, and capable of opening and closing the sealed space; The port portion is a bag-shaped sealed portion in which the periphery except for a part is sealed in a state in which the second laminate film is superimposed; a metal pipe having one end disposed outside the seal portion and communicating with the sealed space, the other end other than the one end disposed within the seal portion, and at least a portion of the outer circumferential surface of the other end fixed to the second laminate film on the periphery of the seal portion via a second sealant film.

4. the sealing portion has an opening on the peripheral edge of the part, 4. The secondary battery according to claim 3, wherein the opening is closable, and the second opening can be formed by cutting away the closed opening.

5. 4. A method for controlling a secondary battery according to claim 1 or 3, comprising: measuring the internal pressure in the sealed space; A control method that issues a warning to reduce the pressure inside the sealed space through the port portion when the measured internal pressure is equal to or higher than a predetermined threshold.

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