Lid, method for manufacturing same, and sealed battery

Abstract

Provided is a lid for a sealed battery, the lid having a relatively simple structure and having a small number of components, and being capable of reliably preventing liquid leakage of an electrolyte solution and intrusion of moisture and the like from the outside. A lid for closing a battery container having an opening, the lid comprising: terminal members (1, 2); a sealing plate (3) having mounting holes (3b) for mounting the terminal members; and a sealing member (4) that attaches and seals the terminal member in the mounting hole (3b), the sealing member containing a polyarylene sulfide resin and an acrylate, the terminal member having a hydroxyl group-containing film on the outer peripheral surface, the sealing plate having a hydroxyl group-containing film on the inner wall surface of the mounting hole, and the terminal member being sealed in the mounting hole of the sealing plate via the sealing member.

Description

Technical Field

[0001] This invention relates to a cover and its manufacturing method, as well as a sealed battery. More specifically, it relates to a cover and its manufacturing method that provide a sealed battery with excellent sealing performance while having a simple structure, and a sealed battery using the cover. Background Technology

[0002] Rechargeable and rechargeable secondary batteries, such as lithium-ion batteries, can be used not only in small mobile devices such as mobile phones and laptops, but also in a wide variety of applications, including transportation vehicles such as automobiles, airplanes, and ships, as well as power supplies for facilities such as factories, buildings, schools, and hospitals.

[0003] These secondary batteries typically house electrodes with positive and negative terminals within a battery container with an opening, and are sealed with a cover. The cover has mounting holes corresponding to the positive and negative terminals, and terminal components are inserted into these holes to connect with leads extending from the electrodes, thereby enabling electrical communication between the inside and outside of the battery.

[0004] However, since the electrolyte in secondary batteries is flammable, a cover structure with excellent impact resistance and reliable liquid leakage prevention is sought as the cover of the battery.

[0005] For example, Patent Document 1 discloses a cover (upper cover assembly) for a sealed battery in which an electrode terminal is placed in an electrode lead-out hole of the upper cover plate through a sealing ring, and an annular fixing member (metal retainer) is covered on the electrode terminal and then welded to the upper cover plate.

[0006] Furthermore, Patent Document 2 discloses a cover structure in which a hole is formed in a metal cover body, and a sealing gasket with a cylindrical portion and made of thermoplastic resin is inserted from the back of the cover body. An external metal terminal is inserted into the cylindrical portion of the sealing gasket. The inner surface of the hole in the cover body is joined with the outer surface of the cylindrical portion of the sealing gasket by laser irradiation, and the inner surface of the cylindrical portion of the sealing gasket is joined with the outer surface of the external terminal by laser irradiation, thereby firmly sealing the cover.

[0007] In addition, Patent Document 3 discloses a cover for a sealed battery, wherein terminal components are mounted on a sealing plate having mounting holes for mounting terminal components.

[0008] In the cover of Patent Document 3, a sealing material comprising polyarylene sulfide resin as a thermoplastic resin and further comprising inorganic filler that suppresses the volume expansion rate of the electrolyte is used. The terminal component is inserted with this sealing material engaged with the periphery of the mounting hole in the sealing plate. At this time, micro-protrusions formed by laser processing, sandblasting, or other methods are provided on the contact surfaces of the terminal component and the sealing material, as well as the contact surfaces of the sealing plate and the sealing material, and these contact surfaces are joined by an anchoring effect. Furthermore, the sealing material is formed by melting polyarylene sulfide resin and inorganic filler, and the cover is formed as described above by injection molding.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Publication No. 2021-526707

[0012] Patent Document 2: Japanese Patent Application Publication No. 2012-33339

[0013] Patent Document 3: Japanese Patent Application Publication No. 2022-103899 Summary of the Invention

[0014] The technical problem that the invention aims to solve

[0015] As mentioned above, in sealed batteries such as lithium-ion secondary batteries, it is necessary to reliably prevent electrolyte leakage, and various cover structures have been explored to date.

[0016] However, in the cover structure as described in Patent Documents 1 and 2, the number of components is large and the number of manufacturing processes is also complicated, resulting in reduced production efficiency.

[0017] On the other hand, although the cover of Patent Document 3 does not use a relatively simple structure with gaskets such as sealing rings and sealing washers, the presence of inorganic fillers in the sealing material sometimes creates an air layer (void) at the contact surface between the terminal component and the sealing material or between the sealing plate and the sealing material. If moisture (such as moisture from the air) is present in the aforementioned air layer, this moisture may cause hydrogen fluoride, a poison, to be generated from the electrolyte (such as fluorinated compounds such as LiPF6) in the electrolyte.

[0018] Therefore, the inventors conducted careful research to solve the above-mentioned problems and found that when the terminal component is mounted on the sealing plate with mounting holes through the sealing member, the sealing member contains polyarylether sulfide resin as a thermoplastic resin and contains one or more polyolefins selected from the group consisting of polyethylene and polypropylene. As a result, a cover for a sealed battery with a simpler structure and excellent impact resistance compared to the past can be obtained, thus completing the present invention.

[0019] Therefore, the purpose of this invention is to provide a cover for a sealed battery with few components, a relatively simple structure, and the ability to reliably prevent electrolyte leakage and the intrusion of moisture from the outside.

[0020] Furthermore, another object of the present invention is to provide a method for manufacturing the above-mentioned cover, and yet another object of the present invention is to provide a sealed battery including the above-mentioned cover.

[0021] Technical means for solving technical problems

[0022] That is, the present invention is a cover for sealing a battery container having an opening, comprising: a terminal member; a sealing plate having a mounting hole for mounting the terminal member; and a closure member that mounts the terminal member into the mounting hole of the sealing plate to seal it, the closure member comprising a polyarylene sulfide resin as a thermoplastic resin and comprising one or more polyolefins selected from the group consisting of polyethylene and polypropylene, the terminal member being sealed in the mounting hole of the sealing plate via the closure member.

[0023] Furthermore, the present invention is a method for manufacturing a cover for sealing a battery container having an opening, characterized in that the cover includes: a terminal member; a sealing plate having a mounting hole for mounting the terminal member; and a closure member that mounts the terminal member in the mounting hole of the sealing plate to seal it, the closure member comprising a polyarylene sulfide resin as a thermoplastic resin and comprising one or more polyolefins selected from the group consisting of polyethylene and polypropylene, wherein the resin forming the closure member is injection molded into the mold with the sealing plate and the terminal member assembled in a mold and with a gap between the mounting hole of the sealing plate and the terminal member, so as to seal the terminal member in the mounting hole of the sealing plate through the closure member.

[0024] Furthermore, the present invention is a sealed battery comprising: an electrode body having a positive electrode and a negative electrode; a battery container having an opening and housing the electrode body; and a cover sealing the opening, the cover comprising: a terminal member; a sealing plate having a mounting hole for mounting the terminal member; and a closure member for mounting the terminal member in the mounting hole of the sealing plate to seal it, the closure member comprising a polyarylene sulfide resin as a thermoplastic resin, and comprising one or more polyolefins selected from the group consisting of polyethylene and polypropylene, the terminal member being sealed in the mounting hole of the sealing plate through the closure member.

[0025] The cover of the present invention includes: a terminal component; a sealing plate having a mounting hole for mounting the terminal component; and a closure member that mounts the terminal component into the mounting hole of the sealing plate to close it.

[0026] The sealing component of the present invention comprises polyarylene sulfide resin as a thermoplastic resin. Polyarylene sulfide resin is an insulating resin and exhibits resistance to fluorinated compounds and hydrogen fluoride contained in the dielectric of the electrolyte. It can form a sealing component that, in addition to excellent adhesion to metals, also possesses excellent chemical corrosion resistance, thermal resistance, and ease of molding. The content of polyarylene sulfide resin in the sealing component can be 50% by mass or more and 100% by mass or less, preferably 70% by mass or more and 99.9% by mass or less.

[0027] As a polyaryl sulfide resin, it has a structure, for example, where benzene rings (p-phenylene) and sulfur atoms (thioether bonds) are alternately bonded, similar to polyphenylene sulfide. Specifically, homopolymers or copolymers composed of p-phenylene sulfide units, m-phenylene sulfide units, o-phenylene sulfide units, sulfone units, ketone units, ether units, and diphenylene sulfide units can be listed. More specifically, polyp-phenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfide ketone, and polyphenylene sulfide ether can be listed. Among these, polyp-phenylene sulfide is preferred due to its particularly excellent heat resistance and strength properties.

[0028] Furthermore, in this invention, the sealing element comprises one or more polyolefins selected from the group consisting of polyethylene and polypropylene. By including polyolefins in addition to polyarylene sulfide resin as the cover of the sealed battery, resistance to external impacts (impact resistance) can be ensured.

[0029] For the polyolefin, preferably, the content in the closure is 0.1% by mass or more and 20% by mass or less. Too little polyolefin content may not achieve its effect, while too much will not yield further results, as the effect will saturate. Within the above-mentioned content range, a cap with excellent impact resistance can be reliably obtained. Specifically, as shown in the examples described later, for injection-molded notched test pieces (notch front radius rN of 0.25mm ± 0.05mm), the Charpy impact strength (notched) measured according to ISO 179 can reach 4kJ / m². 2 above.

[0030] In this invention, the terminal component may also have a hydroxyl-containing coating on its outer peripheral surface. Alternatively, similarly, the sealing plate may also have a hydroxyl-containing coating on the inner wall surface of the mounting hole.

[0031] Hydroxyl-containing coatings can be formed, for example, by laser processing involving laser irradiation. Since the aforementioned hydroxyl-containing coatings have surface irregularities, they are advantageous in terms of exerting an anchoring effect on the sealing element. In the case of laser processing, ideally, the resulting hydroxyl-containing coating should be formed such that the oxygen content in the surface layer, measured by EPMA, is 0.1% by mass or more and 50% by mass or less at a depth of 3 μm from the outermost surface.

[0032] Hydroxyl-containing coatings can be formed not only using laser processing as described above, but also using known methods such as hydration oxide processing with warm or hot water, sandblasting, or chemical formation processing containing organic compounds with hydroxyl groups. Furthermore, the type of hydroxyl-containing coating varies depending on the metal used to form the terminal component or sealing plate. Examples include hydroxides (metal hydroxides) or hydroxyl oxides (metal hydroxyl oxides) of metals such as aluminum hydroxide (Al(OH)3), aluminum hydroxyoxide (AlO(OH)), copper hydroxide (Cu(OH)2), ferrous hydroxide (II) (Fe(OH)2), and iron hydroxyoxide (III) (FeO(OH)). Additionally, hydroxyl-containing coatings can also contain oxides (metal oxides) of metals such as aluminum oxide (Al2O3), copper oxide (I) (Cu2O), copper oxide (II) (CuO), iron oxide (II) (FeO), iron oxide (II, III) (Fe3O4), and iron oxide (III) (Fe2O3), depending on the metal used to form the terminal component or sealing plate.

[0033] Here, laser processing is affected by the irradiation energy per unit area of ​​the laser (hereinafter also referred to as "energy density"). Energy density represents the laser output per unit area per unit time of the laser-irradiated portion of the object (workpiece) being laser-processed. Energy density (J / mm²) 2 The laser output W (W), the number of laser scans N (times), the laser irradiation interval C (mm), the laser scanning speed V (mm / s), the length of the laser-irradiated part perpendicular to the laser irradiation direction Length, and the width of the laser-irradiated part parallel to the laser irradiation direction Width are represented by the following formula (A1).

[0034] Energy density = (((Length / C)×Width×N) / V)×W) / (Length×Width) (Formula A1)

[0035] If we transform formula (A1), we can obtain the following formula (A2). The energy density can be calculated using formula (A2).

[0036] Energy density = (W×N) / (C×V) (Formula A2)

[0037] The preferred energy density is 0.5 J / mm². 2 The above points are relevant. As the energy density increases, fine irregularities with hydroxyl groups tend to form on the surface of the object (workpiece) being laser-treated. Furthermore, a hydroxyl-containing coating with a specified hydroxyl group content is easily formed. When the energy density increases further, the depressions in the macroscopic irregularities formed on the surface of the object (workpiece) become deeper, and the surface roughness after laser treatment tends to increase. Additionally, the higher the melting point of the metal constituting the object (workpiece), the greater the thermal diffusion, and the more susceptible the object (workpiece) is to laser treatment. Considering the above, it is preferable that the energy density is changed accordingly to the metal being laser-treated.

[0038] For example, when laser processing an object (workpiece) with aluminum as the main metal, the preferred energy density is 0.5 J / mm². 2 The above is preferred to be 1J / mm. 2 The above is further preferably 1.5 J / mm. 2 That's all. Furthermore, when performing laser processing on objects (workpieces) with aluminum as the main metal, the preferred energy density is 5 J / mm². 2 Below, 4J / mm is preferred. 2 The following is a further preferred value: 3J / mm 2 the following.

[0039] Furthermore, when performing laser processing on objects (workpieces) with copper as the main metal, the preferred energy density is 2 J / mm². 2 The above is preferred to be 4J / mm. 2 The above is further optimized to 6J / mm 2 That's all. Furthermore, when performing laser processing on objects (workpieces) with copper as the main metal, the preferred energy density is 20 J / mm². 2 The following is more preferably 15 J / mm 2 Hereinafter, 10 J / mm is further preferred. 2 the following.

[0040] In this invention, a flange portion may also be provided on the outer peripheral surface of the terminal member. Similarly, a lip portion may be provided on the inner wall surface of the mounting hole of the sealing plate. Furthermore, by having a flange biting portion that bites the flange portion of the terminal member and a lip biting portion that bites the lip portion of the sealing plate, a robust sealing structure can be achieved.

[0041] Furthermore, in this invention, the closure may also contain polydimethylsiloxane (PMDS) as an additive. By including polydimethylsiloxane (PMDS) in the closure, as described below, the flowability and release properties of the resin composition (which may contain polyolefin or the aforementioned polydimethylsiloxane if desired) injected into the closure via injection molding are improved when the closure is formed by injection molding, thereby improving processability.

[0042] To achieve the aforementioned effects, the closure may preferably contain 0.2% by mass or more and 9.5% by mass of polydimethylsiloxane (PMDS). If the PMDS content is too low, its effect may not be fully achieved; conversely, if it is too high, no further effect can be expected, and the effect will saturate. Within the aforementioned content range, processability during injection molding can be improved. Specifically, as shown in the examples described later, for the injection-molded resin composition, a melt flow rate (MFR) of 20 g / min or higher, measured by the method based on JIS K 7315-2 at 315°C and a 5.00 kg load, can be ensured.

[0043] Furthermore, in this invention, the sealing element may also contain acrylate. In particular, when a hydroxyl-containing coating is provided on the outer peripheral surface of the terminal component and the inner wall surface of the mounting hole in the sealing plate, the carbonyl groups contained in the acrylate will interact with and adhere to the hydroxyl groups of the hydroxyl-containing coating, which can suppress the formation of an air layer between the sealing element and these interfaces, thereby forming a cover with excellent sealing performance.

[0044] Here, for the acrylate contained in the closure, from the viewpoint of facilitating injection molding and obtaining higher adhesion, it is preferred to select one or more of the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, ethyl 2-dimethylaminoacrylate and ethyl 2-hydroxyacrylate.

[0045] When the sealing element contains acrylate and begins to perform the functions described above, the content of acrylate in the sealing element is preferably 0.1% by mass or more and 10% by mass or less. If the content of acrylate is too low, its effect cannot be confirmed; conversely, if it is too high, no further effect can be expected, and the effect will saturate. Therefore, it is ideal to control the content within the above-mentioned range.

[0046] Furthermore, when the closure contains acrylate in addition to polyolefins, these can also form olefin copolymers. Specifically, this refers to an olefin copolymer formed by copolymerizing one or more polyolefins selected from the group consisting of polyethylene and polypropylene with one or more polyolefins selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, ethyl 2-dimethylaminoacrylate, and ethyl 2-hydroxyacrylate, wherein the copolymer is contained as an elastomer in a polyaryl sulfide resin.

[0047] In this invention, the method for obtaining the cover as described above is not particularly limited, but the following method is ideally described. That is, by assembling the sealing plate and the terminal component into a mold, and with a gap between the mounting hole of the sealing plate and the terminal component, resin (resin composition) forming the sealing member is injected, thereby enabling the terminal component to be joined to the mounting hole of the sealing plate through the sealing member.

[0048] At this time, as described above, a hydroxyl-containing coating may be provided on the outer peripheral surface of the terminal component, or a hydroxyl-containing coating may be provided on the inner wall surface of the mounting hole of the sealing plate. In addition, a flange may be formed on the outer peripheral surface of the terminal component, and the sealing member may have a flange biting portion that bites the flange portion, or a lip may be formed on the inner wall surface of the mounting hole of the sealing plate, and the sealing member may have a lip biting portion that bites the lip portion.

[0049] Furthermore, by sealing the opening of the battery container that houses the electrode body using the aforementioned cover, leakage of electrolyte and intrusion of moisture from the outside can be reliably prevented, thereby obtaining a sealed battery with excellent impact resistance.

[0050] Invention Effects

[0051] According to the present invention, a cover can be obtained with few components, a relatively simple structure, and reliable protection against electrolyte leakage and external intrusion of moisture. By using such a cover, a sealed battery with excellent impact resistance can be obtained. Attached Figure Description

[0052] Figure 1 (a) is a schematic plan view showing the front of the cover of the present invention. Figure 1 (b) is a schematic diagram showing the back of the same cover.

[0053] Figure 2 It means Figure 1 The diagram of section II-II of (a) is a schematic cross-sectional diagram illustrating the case where the terminal component is sealed in the mounting hole of the sealing plate by a sealing material.

[0054] Figure 3This is a schematic diagram illustrating the use of a mold assembly to manufacture a cover (with the sealing plate and terminal components embedded in a movable mold).

[0055] Figure 4 This is a schematic diagram used to illustrate the process of manufacturing a cover using a mold device (the state of injecting molten resin after mold closing).

[0056] Figure 5 This is a schematic diagram illustrating the process of manufacturing a cover using a mold device (the state after the mold is opened and the cover is removed after cooling). Detailed Implementation

[0057] The present invention will now be described in more detail with reference to the accompanying drawings.

[0058] Figure 1 An example is shown for illustrating the cover of the present invention. Figure 1 (a) is a schematic diagram showing the front view. Figure 1 (b) is a schematic diagram showing the back side. The cover of the present invention includes: a terminal member 1, which is made of an aluminum electrode and corresponds to a positive electrode; a terminal member 2, which is made of a copper electrode and corresponds to a negative electrode; a sealing plate 3, which has mounting holes 3b for mounting the terminal members 1 and 2, and is made of an aluminum substrate; and a sealing member 4, which mounts the terminal members 1 and 2 into the mounting holes 3b of the sealing plate 3 and seals them.

[0059] In addition, such as Figure 2 As shown, terminal member 1 (terminal member 2) has a flange portion 1a (flange portion 2a) on its respective outer peripheral surface, and sealing plate 3 has a lip portion 3a on the inner wall surface of each mounting hole 3b. Additionally, Figure 2 In the diagram, although the case of terminal member 1, which corresponds to the positive electrode, is shown, the same applies to terminal member 2, which corresponds to the negative electrode.

[0060] Furthermore, the outer peripheral surfaces of the terminal members 1 and 2 include a hydroxyl-containing coating formed by laser processing, such that the front surfaces of the flange portions 1a and 2a are included. Similarly, each mounting hole 3b of the sealing plate 3 also includes a hydroxyl-containing coating formed by laser processing on its inner wall surface, such that the front surfaces of each lip portion 3a are included.

[0061] On the other hand, the closure 4 comprises polyarylene sulfide resin as a thermoplastic resin, and further comprises one or more polyolefins selected from the group consisting of polyethylene and polypropylene. It also includes a flange bit 4a that grips the flange portions 1a and 2a of the terminal members 1 and 2 as described above, and a lip bit 4b that grips the lip portion 3a of the sealing plate 3. At this time, the flange bit 4a of the closure 4 is firmly engaged by the anchoring effect through the surface irregularities of the hydroxyl-containing coating on the outer peripheral surfaces of the terminal members 1 and 2, and similarly, the lip bit 4b of the closure 4 is firmly engaged by the surface irregularities of the hydroxyl-containing coating on the inner surface of the mounting hole 3b of the sealing plate 3.

[0062] In this way, when the terminal components 1 and 2 are sealed in the mounting hole 3b of the sealing plate 3 using the sealing member 4, the sealing plate 3 and the terminal components 1 and 2 are assembled in the mold, and the resin (resin composition) forming the sealing member 4 is injected into the mold with gaps between the mounting hole 3b of the sealing plate 3 and the terminal components 1 and 2 respectively.

[0063] That is, such as Figure 3 As shown, the sealing plate 3 and terminal components 1 and 2 are first assembled (inserted) into the movable mold 5 of the mold assembly, which includes the movable mold 5 and the fixed mold 6. At this time, the mold temperature is preferably set to about 140 to 160°C.

[0064] Next, as Figure 4 As shown, after the mold is closed, molten resin 7 containing polyarylether sulfide resin and acrylic resin, which melts at around 300°C, is injected into the mold.

[0065] Thus, after cooling, as Figure 5 The mold is opened as shown. At this time, the flow channel distributor 8 remains in the fixed mold 6, and a cover is formed in one of the movable molds 5. The cover is formed by the terminal components 1 and 2 being installed in the mounting holes 3b of the sealing plate 3 through the closure 4. The cover is then removed and the process is complete.

[0066] At this time, in the molten resin forming the sealing member 4, in addition to including polyarylene sulfide resin and specified polyolefin as resin components as described above, polydimethylsiloxane and the like may also be included as additives.

[0067] Furthermore, a sealed battery can be obtained by sealing the opening of the battery container housing the electrode body using a cover obtained in the above manner, which reliably prevents electrolyte leakage and the intrusion of moisture from the outside. In particular, according to the present invention, a sealed battery with fewer components, a relatively simple structure, and excellent sealing performance (air tightness) can be obtained, which is suitable for obtaining sealed batteries such as lithium-ion secondary batteries.

[0068] Example

[0069] (Experiments No. 1-15)

[0070] Make it as shown below. Figure 1 , 2 The cover shown was used as a test cover for various evaluation tests.

[0071] First, a sealing plate 3 was prepared, formed from an aluminum sheet of A3003 material with a length of 70mm × width of 172mm × thickness of 2mm, and including mounting holes 3b for mounting terminal member 1 (corresponding to the positive electrode) and mounting holes 3b for mounting terminal member 2 (corresponding to the negative electrode). The inner diameter of the mounting holes 3b in the sealing plate 3 is 28mm, and the mounting holes 3b have a lip 3a with a height of 1mm along their inner wall surface.

[0072] On the other hand, an aluminum electrode is prepared as a terminal member 1, which corresponds to the positive electrode. The aluminum electrode is made of A1060 material with an outer diameter of 18 mm and a height of 3 mm, and has a flange portion 1a with a height of 1 mm on its outer peripheral surface. Furthermore, a copper electrode is prepared as a terminal member 2, which corresponds to the negative electrode. The copper electrode is made of a composite plate of A1060 and C1100 materials with an outer diameter of 18 mm and a height of 3 mm, and similarly has a flange portion 2a with a height of 1 mm on its outer peripheral surface, just like the terminal member 1.

[0073] Here, for the aforementioned terminal components 1 and 2, the flange portions 1a and 2a are irradiated with laser in such a way that their respective outer peripheral surfaces are included. Similarly, for the sealing plate 3, the lip portion 3a is irradiated with laser in such a way that the inner wall surface of its mounting hole 3b is included. The conditions for these laser treatments are as follows.

[0074] <Laser processing conditions>

[0075] • Equipment: Keyence 3-axis fiber laser marking machine (model: MDF-5200)

[0076] Laser wavelength: 1090nm

[0077] • Transmission method: Pulse

[0078] Output: 42.4W

[0079] • Frequency: 60kHz

[0080] • Beam diameter: 60μm

[0081] • Irradiation interval: 90μm

[0082] • Scanning speed: 340mm / s

[0083] • Number of scans (number of irradiations): 1

[0084] • Energy density: 1.45 J / mm 2

[0085] Furthermore, when these terminal components 1 and 2 are installed in the mounting holes 3b of the sealing plate 3 to close them, a resin (resin composition) for forming the sealing element is prepared as shown in Table 1. That is, the resin composition comprises (A) component: polyarylene sulfide resin, (B) component: acrylate, (C) component: polyethylene, and (D) component: polydimethylsiloxane. As component (B), it contains one or more components from the group consisting of (b-1): butyl acrylate, (b-2): methyl acrylate, and (b-3): ethyl acrylate. Additionally, the proportions in Table 1 represent mass%.

[0086] [Table 1]

[0087] (A) Polyarylate sulfide resin, (b-1) Butyl acrylate, (b-2) Methyl acrylate, (b-3) Ethyl acrylate, (C) Polyethylene, (D) Polydimethylsiloxane. The proportions of components (A) to (D) are expressed as mass%.

[0088] Using the resin composition prepared above for forming the sealing element, by Figures 3-5 The mold apparatus shown was used to manufacture the cover. The injection molding conditions at this time are as described below, thereby obtaining the test cover for each test number. Furthermore, the test cover obtained in the above manner was evaluated as follows.

[0089] Mold temperature: 140℃~160℃

[0090] Melting resin temperature: 290℃~310℃

[0091] Injection speed: 50~80mm / second

[0092] Filling peak pressure: 60~120MPa

[0093] Pressure holding: 60~80MPa

[0094] Cooldown time: 20-30 seconds

[0095] [Oxygen content in hydroxyl-containing coatings (coating oxygen content)]

[0096] The flange portion 1a of the terminal member 1, before the closure 4 is joined, was cross-sectionally mapped using an electron probe microanalyzer (EPMA, manufactured by Shimadzu Corporation: EPMA-1610). Mapping analysis was performed under the following conditions: irradiation diameter of 40 μm / step, with 512 steps measured in both the longitudinal and transverse directions. Here, the measurement area was 20.48 mm × 20.48 mm, the sampling time per step was 20 ms, the accelerating voltage was 15 kV, and the oxygen resolution in the depth direction was less than 3 μm.

[0097] Next, the detected oxygen intensity was calculated as a weight percentage (wt%) based on a pre-established calibration curve. The calibration curve was calculated using the oxygen intensity of an Al2O3 standard sample (oxygen content: 48wt%) and high-purity aluminum foil. The results are shown in Table 1.

[0098] [Flowability Evaluation of Resin Composition]

[0099] For the resin composition used to form the closure in the test cap, its flowability was evaluated using a method based on JIS K 7315-2. The melt flow rate (MFR) was determined under conditions of 315°C and a load of 5.00 kg. Here, the resin composition for test number 1 was measured as described above, but the melt flow rate (MFR) was 50 g / min.

[0100] [Compressive Strength Evaluation (Bond Strength)]

[0101] To confirm the sealing strength achieved by the sealing member 4 of the terminal components 1 and 2 in the test cover, the compressive strength was measured using a universal testing machine (STROGRAPH T200) manufactured by Toyo Seiki Co., Ltd. First, the test cover was placed on the test stage of the universal testing machine, and the front end of the pressing clamp was pressed down from directly above the terminal components 1 and 2 at a certain speed (10 mm / min). The load at which the sealing member 4 breaks due to the terminal components 1 and 2 detaching from the mounting hole 3b of the sealing plate 3 was used as the compressive strength calculation. A compressive strength of 2000 N or more was evaluated as acceptable (○), and a compressive strength less than 2000 N was evaluated as unacceptable (×).

[0102] [Air tightness evaluation (bond strength)]

[0103] To evaluate the airtightness (air tightness) of terminal components 1 and 2 in the test cover, a helium leak test was conducted using a helium leak detector (HELIOT 901W1 manufactured by Alback). One of the terminal components 1 or 2 in the test cover was placed on the lower fixture of the helium leak detector, made of SUS304 stainless steel, through an O-ring. A coarse pump and a turbomolecular pump were used to evacuate the system until the helium leakage value reached 1 × 10⁻⁶. -12 Pa m³ / s unit. Next, the upper fixture made of SUS304 was placed on the test cover through the O-ring, and helium (He) was injected into the interior of the upper fixture. The opening of the upper fixture was covered with a resin cover, and the amount of helium leaking from the terminal components 1 and 2, which were sealed by the closure 4, was measured. If the helium leakage value was less than 1 × 10⁻⁶ m³ / s, the test was considered complete. -7 Pa If the value is m³ / s, it is rated as qualified (○); if it is 1×10 -7 Pa If the strength is above m³ / s, it is evaluated as unqualified (×). Furthermore, previous compressive strength evaluations are included; if all evaluations are qualified, it is marked "○", and if any evaluation is unqualified, it is marked "×". The results are shown in Table 1.

[0104] Charpy impact test (with notch)

[0105] Charpy impact strength of notched test caps was measured according to ISO 179 / 1eA. Notched test pieces (notch radius rN = 0.25 mm ± 0.05 mm) were prepared by injection molding, and their impact strength was measured. The results are shown in Table 1.

[0106] The results above show that the resin used to form the sealing element contains both polyarylether resin and polyolefin, thereby achieving a cap structure with excellent impact resistance.

[0107] Symbol Explanation

[0108] 1 and 2 terminal components; 1a, 2a Flange portions; 3. Sealing plate; 3a. Lip edge; 3b mounting holes; 4. Enclosures; 4a Flange bite; 4b. Lip edge biting area; 5. Movable mold; 6. Fixed mold; 7. Molten resin; 8. Flow channel splitter.

Claims

1. A cover for sealing a battery container having an opening, characterized in that, include: Terminal components; A sealing plate having mounting holes for mounting the terminal component; as well as A closure member that mounts the terminal component into the mounting hole of the sealing plate to close it. The closure comprises a polyarylene sulfide resin as a thermoplastic resin, and includes one or more polyolefins selected from the group consisting of polyethylene and polypropylene. The terminal component is enclosed in the mounting hole of the sealing plate through the closure member.

2. The cover as described in claim 1, characterized in that, The closure comprises 0.1% by mass and less than 20% by mass of the polyolefin.

3. The cover as described in claim 1, characterized in that, The terminal component has a hydroxyl-containing coating on its outer peripheral surface, and the sealing plate has a hydroxyl-containing coating on the inner wall surface of the mounting hole.

4. The cover as described in claim 3, characterized in that, The oxygen content of the hydroxyl-containing coating, measured by EPMA, is greater than 0.1% by mass and less than 50% by mass in the surface layer at a depth of 3 μm from the outermost surface.

5. The cover as described in claim 1, characterized in that, The closure contains polydimethylsiloxane as an additive.

6. A method for manufacturing a cover, comprising manufacturing the cover according to claim 1, characterized in that, By assembling the sealing plate and the terminal component into a mold, and with a gap between the mounting hole of the sealing plate and the terminal component, resin forming the closure is injected to seal the terminal component in the mounting hole of the sealing plate through the closure.

7. A sealed battery, characterized in that, include: An electrode body having a positive electrode and a negative electrode; A battery container having an opening and housing the electrode body; as well as The cover according to claim 1, wherein the cover seals the opening.

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