Lid, method for manufacturing the same, and sealed battery

Abstract

Provided is a lid body of a sealed battery, the lid body being capable of reliably preventing liquid leakage of an electrolyte and intrusion of moisture or the like from the outside while having a small number of components and a relatively simple structure.　The lid body for closing a battery container having an opening comprises: terminal members 1, 2; a sealing plate 3 having attachment holes 3b to which the terminal members are attached; and a sealing material 4 that seals the terminal members after being attached to the attachment holes 3b. The sealing material contains a polyarylene sulfide resin and contains an acrylic acid ester. In addition, the terminal member has a hydroxyl group-containing film on the outer circumferential surface, and the sealing plate has a hydroxyl group-containing film on the inner circumferential surface of the attachment hole. The terminal members are sealed in the attachment holes of the sealing plate via the sealing material.

Description

[Technical Field]

[0001] This invention relates to a lid, a method for manufacturing the same, and a sealed battery, and more specifically, to a lid, a method for manufacturing the same, and a sealed battery using the same, which can provide a sealed battery with excellent sealing properties while having a simple structure. [Background technology]

[0002] Rechargeable batteries such as lithium-ion batteries, which can be repeatedly charged and discharged, are widely used in a variety of applications, including small mobile devices such as mobile phones and laptops, as well as transportation vehicles such as automobiles, aircraft, and ships, and power supplies for facilities such as factories, buildings, schools, and hospitals.

[0003] These rechargeable batteries generally consist of an electrode body with a positive and a negative electrode housed in a battery container with an opening, which is then sealed by a lid. The lid has mounting holes corresponding to the positive and negative electrodes, through which terminal members are inserted and connected to lead wires extending from the electrode body, thereby enabling electrical conductivity between the inside and outside of the battery.

[0004] However, since the electrolyte used in secondary batteries is flammable, the battery cover requires a highly sealing structure that can prevent leakage.

[0005] For example, Patent Document 1 discloses a sealed battery cover (top cover assembly) in which electrode terminals are placed in electrode lead-out holes of the top cover plate via a sealing ring, and a ring-shaped fixing member (metal holder) is placed over these electrode terminals and welded to the top cover plate.

[0006] Furthermore, Patent Document 2 discloses a lid structure in which a hole is formed in a metal lid, a seal gasket made of thermoplastic resin having a cylindrical portion is inserted from the back surface of the lid, and a metal external terminal is inserted into the cylindrical portion of the seal gasket, and the inner surface of the hole (hole) in the lid and the outer surface of the cylindrical portion of the seal gasket are joined by laser irradiation, and the inner surface of the cylindrical portion of the seal gasket and the outer surface of the external terminal are joined by laser irradiation to firmly seal the lid structure.

[0007] Furthermore, Patent Document 3 discloses a lid for a sealed battery in which a terminal member is attached to a sealing plate having mounting holes (holes) for attaching the terminal member.

[0008] In the lid according to Patent Document 3, a sealing material is used which contains polyarylene sulfide resin as a thermoplastic resin and further contains an inorganic filler whose volume expansion rate with respect to the electrolyte is suppressed. The terminal member is inserted through the lid with the sealing material joined to the peripheral edge of the mounting hole in the sealing plate. At this time, the contact surface of the terminal member to the sealing material and the contact surface of the sealing plate to the sealing material are provided with fine irregularities formed by laser treatment or sandblasting, etc., so that these contact surfaces are joined by an anchoring effect. Furthermore, this sealing material is formed by melting the polyarylene sulfide resin and the inorganic filler and forming the lid as described above by injection molding. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Special Publication No. 2021-526707 [Patent Document 2] Japanese Patent Publication No. 2012-33339 [Patent Document 3] Japanese Patent Publication No. 2022-103899 [Overview of the project] [Problems that the invention aims to solve]

[0010] As mentioned above, in sealed batteries such as lithium-ion secondary batteries, it is necessary to reliably prevent electrolyte leakage, and various lid structures have been considered to date.

[0011] However, with lid structures like those in Patent Documents 1 and 2 mentioned above, the number of parts is large and the number of manufacturing steps increases, resulting in reduced production efficiency.

[0012] On the other hand, although the cover described in Patent Document 3 has a relatively simple structure without using gaskets such as sealing rings or seal gaskets, the presence of inorganic fillers contained in the sealing material can cause air layers (voids) to form at the contact surfaces between the terminal member and the sealing material, or between the sealing plate and the sealing material. If moisture (such as moisture from the air) is present in such air layers, there is a risk that toxic hydrogen fluoride may be generated from the electrolyte in the electrolyte solution (for example, fluorine-containing compounds such as LiPF6) due to that moisture.

[0013] Therefore, the present inventors diligently studied to solve the above problems and found that by attaching a terminal member to a sealing plate having mounting holes via a sealing material, and by making the sealing material contain both polyarylene sulfide resin as a thermoplastic resin and acrylic acid ester, a sealed battery cover with a simpler structure than conventional ones and excellent sealing properties can be obtained, thus completing the present invention.

[0014] Therefore, the object of the present invention is to provide a lid for a sealed battery that has a small number of parts and a relatively simple structure, while reliably preventing electrolyte leakage and the intrusion of moisture from the outside.

[0015] Another object of the present invention is to provide a method for manufacturing the above-mentioned lid, and yet another object of the present invention is to provide a sealed battery equipped with the above-mentioned lid. [Means for solving the problem]

[0016] That is, the present invention is a lid for closing a battery container having an opening, a terminal member, a sealing plate having a mounting hole for mounting the terminal member, and a sealing material for mounting and sealing the terminal member in the mounting hole of the sealing plate, where the sealing material contains a polyarylene sulfide resin as a thermoplastic resin and contains an acrylate ester, the terminal member has a hydroxyl group-containing film on its outer peripheral surface, and the sealing plate has a hydroxyl group-containing film on the inner wall surface of the mounting hole, and the terminal member is sealed in the mounting hole of the sealing plate via the sealing material. The lid is characterized by this.

[0017] Furthermore, the present invention is a method for manufacturing a lid for closing an opening of a battery container, where the lid comprises a terminal member, a sealing plate having a mounting hole for mounting the terminal member, and a sealing material for mounting and sealing the terminal member in the mounting hole of the sealing plate, the sealing material contains a polyarylene sulfide resin as a thermoplastic resin and contains an acrylate ester, the terminal member has a hydroxyl group-containing film on its outer peripheral surface, and the sealing plate has a hydroxyl group-containing film on the inner wall surface of the mounting hole, the sealing plate and the terminal member are arranged in a mold, a resin for forming the sealing material is injection-molded in a state where a gap is provided between the mounting hole of the sealing plate and the terminal member, and the terminal member is sealed in the mounting hole of the sealing plate via the sealing material. The method for manufacturing a lid is characterized by this.

[0018] Furthermore, the present invention is a sealed battery, where the sealed battery comprises an electrode body having a positive electrode and a negative electrode, a battery container having an opening and accommodating the electrode body, and a lid for closing the opening, and the lid Terminal member and A sealing plate having mounting holes for attaching the terminal member, The terminal member is attached to the mounting hole of the sealing plate and sealed with a sealing material, The sealing material contains a polyarylene sulfide resin as a thermoplastic resin and also contains an acrylic acid ester. The terminal member has a hydroxyl group-containing coating on its outer surface, and the sealing plate has a hydroxyl group-containing coating on the inner wall surface of the mounting hole. The sealed battery is characterized in that the terminal member is sealed in the mounting hole of the sealing plate via the sealing material.

[0019] The lid in the present invention comprises a terminal member, a sealing plate having mounting holes for attaching the terminal member, and a sealing material for attaching the terminal member to the mounting holes of the sealing plate and sealing it.

[0020] Of these, the terminal member has a hydroxyl group-containing coating on its outer surface, and the sealing plate has a hydroxyl group-containing coating on the inner wall surface of the mounting hole. On the other hand, the sealing material contains polyarylene sulfide resin as a thermoplastic resin, as well as acrylic acid ester.

[0021] Here, the hydroxyl groups of the hydroxyl group-containing coating on the outer surface of the terminal member and the hydroxyl groups of the hydroxyl group-containing coating on the inner wall surface of the mounting hole in the sealing plate interact with the carbonyl groups of the acrylic acid ester contained in the sealing material, resulting in a strong adhesion. This suppresses the formation of an air layer at these interfaces, making it possible to create a lid with excellent sealing properties.

[0022] Such hydroxyl group-containing coatings vary depending on the type of metal forming the terminal member or sealing plate. Examples include metal hydroxides (metal hydroxides) or metal oxide hydroxides (metal oxide hydroxides) such as aluminum hydroxide (Al(OH)3), aluminum oxide hydroxide (AlO(OH)), copper hydroxide (Cu(OH)2), iron(II) hydroxide (Fe(OH)2), and iron(III) oxide (FeO(OH)). Furthermore, depending on the metal forming the terminal member or sealing plate, the hydroxyl group-containing coating may also contain metal oxides (metal oxides) such as aluminum oxide (Al2O3), copper(I) oxide (Cu2O), copper(II) oxide (CuO), iron(II) oxide (FeO), iron(II,III) oxide (Fe3O4), and iron(III) oxide (Fe2O3).

[0023] Hydroxyl group-containing films can be formed using known methods, such as laser treatment with laser light irradiation, hydrated oxide treatment with hot water or hot water, zincate treatment, and chemical conversion treatment containing organic compound components having hydroxyl groups. Among these, laser treatment is preferable because it is advantageous in that it forms surface irregularities and exhibits an anchoring effect. In the case of this laser treatment, preferably, the resulting hydroxyl group-containing film can be formed in which oxygen elements are localized on the surface layer such that the oxygen content measured by EPMA in the surface layer up to a depth of 3 μm from the outermost surface is 0.1% by mass or more and 50% by mass or less.

[0024] Here, laser processing is affected by the irradiation energy of the laser light per unit area (hereinafter also referred to as "energy density"). Energy density represents the laser power received per unit area and per unit time by the laser-irradiated area of ​​the object (workpiece) being laser-treated. Energy density (J / mm 2The laser beam output W (W), the number of laser beam scans N (times), the laser beam irradiation interval C (mm), the laser beam scanning speed V (mm / s), the length perpendicular to the laser beam irradiation direction in the laser-irradiated area, and the width parallel to the laser beam irradiation direction in the laser-irradiated area are expressed by the following formula (A1). Energy density = (((Length / C) × Width × N) / V) × W) / (Length × Width) ... Equation (A1) By rearranging equation (A1), we obtain the following equation (A2). The energy density can be calculated using equation (A2). Energy density = (W × N) / (C × V) ... Equation (A2)

[0025] The energy density is preferably 0.5 J / mm². 2 The above explains the process. As the energy density increases, fine irregularities containing hydroxyl groups are more likely to form on the surface of the laser-treated object (workpiece). Furthermore, a hydroxyl group-containing film with a predetermined hydroxyl group abundance is more likely to form. In addition, as the energy density increases, the depressions in the macro-irregularities formed on the surface of the object (workpiece) tend to become deeper, resulting in a greater surface roughness after laser treatment. Note that the higher the melting point and greater the thermal diffusion of the metal constituting the object (workpiece), the less susceptible the object (workpiece) is to the effects of the laser light. Considering the above circumstances, it is desirable to adjust the energy density according to the metal being laser-treated.

[0026] For example, when performing laser processing on an object (workpiece) whose main metal is aluminum, the energy density is preferably 0.5 J / mm². 2 The above is more than 1 J / mm 2 More preferably 1.5 J / mm 2 The above is preferable. Furthermore, when performing laser processing on an object (workpiece) whose main metal is aluminum, the energy density is preferably 5 J / mm². 2 More preferably 4J / mm 2More preferably, it is 3 J / mm or less. 2 This is preferably the case.

[0027] In addition, when performing laser processing on an object (work) mainly made of copper, the energy density is preferably 2 J / mm or more, 2 more preferably 4 J / mm or more, 2 even more preferably 6 J / mm or more. 2 This is preferably the case. In addition, when performing laser processing on an object (work) mainly made of copper, the energy density is preferably 20 J / mm or less, 2 more preferably 15 J / mm or less, 2 even more preferably 10 J / mm or less. 2 This is preferably the case.

[0028] In the present invention, the terminal member may be provided with a flange portion on its outer peripheral surface. Similarly, the mounting hole of the sealing plate may be provided with a collar portion on its inner wall surface. Then, by making the sealing material have a flange holding portion that holds the flange portion of the terminal member and a collar holding portion that holds the collar portion of the sealing plate, a strong sealing structure can be achieved. In particular, by forming a hydroxyl group-containing film on the outer peripheral surface of the terminal member at the flange portion and forming a hydroxyl group-containing film in the mounting hole of the sealing plate at the collar portion, the interaction between the hydroxyl group and the carbonyl group as described above is expressed, and a stronger sealing structure can be obtained.

[0029] On the other hand, the sealing material in the present invention contains a polyarylene sulfide resin as a thermoplastic resin. The polyarylene sulfide resin is an insulating resin, has resistance to fluorine-containing compounds and hydrogen fluoride contained in the electrolyte in the electrolytic solution, and can be made into a sealing material excellent in adhesion to metals, chemical resistance, cold and heat resistance, and good moldability. The content of the polyarylene sulfide resin in the sealing material is preferably 50% by mass or more and 100% by mass or less, and more preferably 70% by mass or more and 99.9% by mass or less.

[0030] This polyarylene sulfide resin has a structure in which, for example, benzene rings (p-phenylene groups) and sulfur atoms (sulfide bonds) are alternately bonded, such as polyphenylene sulfide. Specifically, examples include homopolymers or copolymers consisting of p-phenylene sulfide units, m-phenylene sulfide units, o-phenylene sulfide units, phenylene sulfide sulfone units, phenylene sulfide ketone units, phenylene sulfide ether units, and biphenylene sulfide units. More specifically, examples include poly(p-phenylene sulfide), polyphenylene sulfide sulfone, polyphenylene sulfide ketone, and polyphenylene sulfide ether. Among these, poly(p-phenylene sulfide) is preferred because it has particularly excellent heat resistance and strength properties.

[0031] Furthermore, the acrylic acid ester contained in the sealing material is not particularly limited as long as it has a carbonyl group that can interact with the hydroxyl groups of the hydroxyl group-containing film. However, from the viewpoint of ease of injection molding and obtaining higher adhesion, it is preferable that it be one or more selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, 2-dimethylaminoethyl acrylate, and 2-hydroxyethyl acrylate.

[0032] The acrylic acid ester is preferably contained in the sealing material in an amount of 0.1% to 10% by mass. If the acrylic acid ester content is too low, it may be difficult to ensure proper adhesion with the mounting holes in the terminal members and sealing plates, while if it is too high, the effect will saturate and no further effect can be expected. Within the above content range, sufficient adhesion with the mounting holes in the terminal members and sealing plates can be ensured.

[0033] Furthermore, in the present invention, the sealing material may include one or more polyolefins selected from the group consisting of polyethylene and polypropylene. If the sealing material further includes polyolefins in addition to polyarylene sulfide resin and acrylic acid ester, resistance to external impacts (impact resistance) can be ensured.

[0034] When the sealing material contains polyolefin, it is preferable that the polyolefin content be between 0.1% by mass and 20% by mass. If the polyolefin content is too low, the effect may not be sufficiently obtained, and conversely, if it is too high, the effect will saturate and no further effect can be expected. Within the above content range, a lid with excellent impact resistance can be obtained. Specifically, as shown in the examples described later, the Charpy impact strength (with notch) measured according to ISO 179 for a notched test piece (notch tip radius rN of 0.25 mm ± 0.05 mm) obtained by injection molding was 4 kJ / m 2 The above can be achieved.

[0035] Furthermore, if the encapsulant contains polyolefins in addition to acrylic acid esters, these may be used to form an olefin copolymer. Specifically, this is an olefin copolymer obtained by copolymerizing one or more selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, 2-dimethylaminoethyl acrylate, and 2-hydroxyethyl acrylate with one or more polyolefins selected from the group consisting of polyethylene and polypropylene, and this copolymer is included as an elastomer in the polyarylene sulfide resin.

[0036] Furthermore, in the present invention, the encapsulant may contain polydimethylsiloxane (PMDS) as an additive. By including polydimethylsiloxane (PMDS) in the encapsulant, as described later, when forming the encapsulant by injection molding, the fluidity and release properties of the resin composition (which optionally includes polyolefin and the polydimethylsiloxane) containing at least a polyarylene sulfide resin and an acrylic acid ester can be enhanced, thereby improving processability.

[0037] To achieve such effects, it is preferable that the encapsulant contains 0.2% to 9.5% by mass of polydimethylsiloxane (PMDS). If the amount of polydimethylsiloxane (PMDS) is too low, the effect may not be sufficiently obtained, and conversely, if it is too high, the effect will saturate and no further effect can be expected. Within the above content range, processability during injection molding can be improved. Specifically, as shown in the examples described later, the melt flow rate (MFR) of the resin composition to be injected can be ensured to be 20 g / min or more, measured at 315°C and under a 5.00 kg load according to the method in accordance with JIS K 7315-2.

[0038] In the present invention, there are no particular limitations on the method for obtaining such a lid, but the following methods are preferred. In other words, by placing the aforementioned sealing plate and terminal member inside a mold, leaving a gap between the mounting hole of the sealing plate and the terminal member, and then injecting a resin (resin composition) that forms the sealing material, the terminal member can be joined to the mounting hole of the sealing plate via the sealing material.

[0039] In this case, as described above, the terminal member may have a hydroxyl group-containing coating on its outer circumferential surface, or a hydroxyl group-containing coating on the inner wall surface of the mounting hole in the sealing plate. Alternatively, a flange portion may be formed on the outer circumferential surface of the terminal member to provide a flange-clamping portion for the sealing material to grip, or a flange portion may be formed on the inner wall surface of the mounting hole in the sealing plate to provide a flange-clamping portion for the sealing material to grip. In particular, if these flange portions or flange portions have a hydroxyl group-containing coating, the hydroxyl groups of the hydroxyl group-containing coating and the carbonyl groups of the acrylic acid ester forming the sealing material interact to form a strong bond, resulting in a lid structure with excellent sealing (airtightness).

[0040] Furthermore, by using such a lid to seal the opening of the battery container housing the electrodes, a sealed battery can be obtained that reliably prevents electrolyte leakage and the intrusion of moisture from the outside. [Effects of the Invention]

[0041] According to the present invention, a lid can be obtained that has a small number of parts and a relatively simple structure, while reliably preventing electrolyte leakage and the intrusion of moisture from the outside. Furthermore, in the sealed battery obtained by the present invention, the formation of an air layer in the sealing material of the lid structure can be eliminated as much as possible, thereby reliably eliminating the risk of moisture remaining in the air layer entering the inside of the battery and mixing with the electrolyte. [Brief explanation of the drawing]

[0042] [Figure 1] Figure 1(a) is a schematic plan view illustrating the surface of the lid according to the present invention, and Figure 1(b) is a schematic plan view illustrating the back surface. [Figure 2] Figure 2 shows the II-II cross-section of Figure 1(a), and is a schematic cross-sectional diagram illustrating how the terminal member is sealed in the mounting hole of the sealing plate with sealing material. [Figure 3] Figure 3 is a schematic diagram illustrating the process of manufacturing a lid using a mold device (with the sealing plate and terminal member inserted into the movable mold). [Figure 4] Figure 4 is a schematic diagram illustrating the process of manufacturing a lid using a mold device (showing the state after the mold has been clamped and molten resin has been injected). [Figure 5] Figure 5 is a schematic diagram illustrating the process of manufacturing a lid using a mold device (showing the state after cooling, when the mold is opened and the lid is removed). [Modes for carrying out the invention]

[0043] The present invention will be described in more detail below with reference to the drawings. Figure 1 shows an example illustrating the lid according to the present invention, where Figure 1(a) is a schematic plan view showing the front surface and Figure 1(b) is a schematic plan view showing the back surface. The lid of the present invention comprises a terminal member 1 made of an aluminum electrode corresponding to the positive electrode, a terminal member 2 made of a copper electrode corresponding to the negative electrode, a sealing plate 3 made of an aluminum base material having mounting holes 3b for attaching these terminal members 1 and 2, and a sealing material 4 for attaching and sealing the terminal members 1 and 2 to the mounting holes 3b of the sealing plate 3, respectively.

[0044] Furthermore, as shown in Figure 2, each terminal member 1 (terminal member 2) has a flange portion 1a (flange portion 2a) on its outer circumferential surface, and the sealing plate 3 has a flange portion 3a on the inner wall surface of each mounting hole 3b. Note that Figure 2 shows the configuration of terminal member 1, which corresponds to the positive electrode, but the same applies to terminal member 2, which corresponds to the negative electrode.

[0045] Furthermore, the outer surfaces of the terminal members 1 and 2 are provided with a hydroxyl group-containing coating formed by laser processing, including the surfaces of the flange portions 1a and 2a. Similarly, each mounting hole 3b of the sealing plate 3 is also provided with a hydroxyl group-containing coating formed by laser processing, including the surfaces of the respective flange portions 3a, on its inner wall surface.

[0046] On the other hand, the sealing material 4 contains polyarylene sulfide resin as a thermoplastic resin, as well as acrylic acid ester, and has a flange gripping portion 4a that grips the flange portions 1a and 2a of the terminal members 1 and 2 as described above. Similarly, the sealing material 4 has a flange gripping portion 4b that grips the flange portion 3a of the sealing plate 3. In this case, the hydroxyl groups of the hydroxyl group-containing coating on the outer surface of the terminal members 1 and 2 interact with the carbonyl groups of the acrylic acid ester to form a strong bond, and the hydroxyl groups of the hydroxyl group-containing coating on the inner wall surface of the mounting hole 3b of the sealing plate 3 interact with the carbonyl groups of the acrylic acid ester to form a strong bond.

[0047] In this way, when sealing the terminal members 1 and 2 into the mounting holes 3b of the sealing plate 3 with the sealing material 4, the sealing plate 3 and the terminal members 1 and 2 are placed inside the mold, and a gap is created between the mounting holes 3b of the sealing plate 3 and the terminal members 1 and 2, allowing the resin (resin composition) forming the sealing material 4 to be injected.

[0048] Specifically, as shown in Figure 3, first, the sealing plate 3 and terminal members 1 and 2 are placed (inserted) into the movable mold 5 of the mold apparatus, which is equipped with a movable mold 5 and a fixed mold 6. At this time, the mold temperature should be set to around 140 to 160°C. Next, as shown in Figure 4, after clamping the mold, molten resin 7 containing polyarylene sulfide resin and acrylic acid ester, melted at approximately 300°C, is injected. In this way, after cooling, the mold is opened as shown in Figure 5. At this point, the sprue runner 8 remains in the fixed mold 6, while the movable mold 5 has a lid formed with terminal members 1 and 2 attached to the respective mounting holes 3b of the sealing plate 3 with sealing material 4. This lid is then removed to complete the process.

[0049] In this case, the molten resin forming the encapsulant 4 may, as described above, include polyolefins such as polyethylene and polypropylene in addition to polyarylene sulfide resin and acrylic acid ester as part of the resin composition, and may also include polydimethylsiloxane or the like as an additive.

[0050] Furthermore, by using the lid obtained in this way to seal the opening of the battery container housing the electrode body, a sealed battery can be obtained that reliably prevents electrolyte leakage and the intrusion of moisture from the outside. In particular, according to the present invention, a sealed battery with excellent sealing properties (airtightness) can be obtained while having a small number of parts and a relatively simple structure, making it suitable for obtaining sealed batteries such as lithium-ion secondary batteries. [Examples]

[0051] (Exam No. 1-18) The lids shown in Figures 1 and 2 were fabricated as described below, and various evaluation tests were conducted using them as test lids.

[0052] First, a sealing plate 3 was prepared, made from an aluminum plate material of A3003 material measuring 70 mm in length, 172 mm in width, and 2 mm in thickness, and equipped with mounting holes 3b for attaching terminal member 1 corresponding to the positive electrode and mounting holes 3b for attaching terminal member 2 corresponding to the negative electrode. The mounting holes 3b in this sealing plate 3 have an inner diameter of 28 mm, and the mounting holes 3b have a flange portion 3a with a height of 1 mm along their inner wall surface.

[0053] On the other hand, an aluminum electrode was prepared as terminal member 1 corresponding to the positive electrode. This 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 surface. In addition, a copper electrode was prepared as terminal member 2 corresponding to the negative electrode. This copper electrode is made of clad material of A1060 material and C1100 material with an outer diameter of 18 mm and a height of 3 mm, and, like terminal member 1, has a flange portion 2a with a height of 1 mm on its outer surface.

[0054] Here, the flange portions 1a and 2a of the terminal members 1 and 2 were irradiated with a laser, including their respective outer surfaces. Similarly, the flange portion 3a of the sealing plate 3 was irradiated with a laser, including the inner wall surface of its mounting hole 3b. The conditions for these laser treatments are as follows. <Laser processing conditions> • Equipment: Keyence Corporation, 3-axis fiber laser marker (Model: MDF-5200) • Laser wavelength: 1090nm • Transmission method: pulse Output: 42.5W • Frequency: 60kHz Beam diameter: 60 μm • Irradiation interval: 90 μm • Scanning speed: 340 mm / s • Number of scans (number of irradiations): 1 • Energy density: 1.45 J / mm² 2

[0055] Then, in order to attach these terminal members 1 and 2 to the respective mounting holes 3b of the sealing plate 3 and seal them, a resin (resin composition) to form the sealing material was prepared as shown in Table 1. Specifically, this resin composition contains (A) component: polyarylene sulfide resin, (B) component: acrylic acid ester, (C) component: polyethylene, and (D) component: polydimethylsiloxane. Of these, component (B) was blended with one or more from the group consisting of (b-1): butyl acrylate, (b-2): methyl acrylate, and (b-3): ethyl acrylate. The percentages in Table 1 are shown in mass %.

[0056] [Table 1]

[0057] Using the resin composition for forming the sealing material prepared above, lids were fabricated using the mold apparatus shown in Figures 3-5. The injection molding conditions were as follows, and test lids corresponding to each test number were obtained. Furthermore, each of the test lids obtained in this manner was evaluated as follows. Mold temperature: 140℃~160℃ Molten resin temperature: 290℃~310℃ Injection speed: 50~80mm / sec Filling peak pressure: 60-120 MPa Holding pressure: 60-80 MPa Cooling time: 20~30 seconds

[0058] [Oxygen content in hydroxyl group-containing coating (coating oxygen content)] Cross-sectional mapping was performed on the flange portion 1a of the terminal member 1 before the sealing material 4 was bonded, using an Electron Probe Micro Analyzer (EPMA) (Shimadzu Corporation: EPMA-1610). The measurement conditions were a mapping analysis with an irradiation diameter of 40 μm / step and 512 steps each in the longitudinal and transverse directions. The measurement area was 20.48 mm × 20.48 mm, the sampling time per step was 20 ms, the acceleration voltage was 15 kV, and the oxygen depth resolution was 3 μm or less.

[0059] Next, the detected oxygen intensity was calculated as a weight percentage (wt%) using a pre-prepared calibration curve. The calibration curve used was created by calculating the oxygen intensity of an Al2O3 standard sample (oxygen content: 48 wt%) and the oxygen intensity of high-purity Al foil. The results are shown in Table 1.

[0060] [Evaluation of the fluidity of resin compositions] The fluidity of the resin composition used to form the sealant in the test lid was evaluated according to the method in accordance with JIS K 7315-2. The melt flow rate (MFR) was determined under conditions of 315°C and a 5.00 kg load. For the resin composition of Test No. 1, the melt flow rate (MFR) was 50 g / min, as measured as described above.

[0061] [Evaluation of compressive strength (adhesive strength)] To confirm the sealing strength of the terminal members 1 and 2 in the test lid by the sealing material 4, the compressive strength was measured using a Toyo Seiki Manufacturing Co., Ltd. universal testing machine (STROGRAPH T200). First, the test lid was set on the sample stage of the universal testing machine, and the tip of the pressing jig was pressed down on the terminal members 1 and 2 from directly above at a constant speed (10 mm / min). The load at which the sealing material 4 broke, causing the terminal members 1 and 2 to detach from the mounting holes 3b of the sealing plate 3, was calculated as the compressive strength. A compressive strength of 2000 N or more was evaluated as a pass (○), and a value of less than 2000 N was evaluated as a fail (×).

[0062] [Airtightness evaluation (adhesive strength)] To evaluate the sealing performance (airtightness) of terminal members 1 and 2 on the test cover, a helium leak test was performed using a helium leak detector (HELIOT 901W1, manufactured by ULVAC, Inc.). One of the terminal members 1 and 2 on the test cover was set in the lower fixture made of SUS304 attached to the helium leak detector via an O-ring, and the helium leak value was 1 × 10⁻⁶. -12 Pa·m 3 Vacuum was evacuated using a roughing pump and a turbomolecular pump until the pressure reached the s / s range. Next, a SUS304 upper fixture was set on the above test lid via an O-ring, helium (He) gas was injected into the upper fixture, a resin lid was placed over the opening of the upper fixture, and the amount of He gas leaking from terminal members 1 and 2, which were sealed with sealing material 4, was detected. The He leak value was 1 × 10⁻⁶. -7 Pa·m 3 If it is less than / s, it will be considered a pass (〇), 1 x 10 -7 Pa·m 3 If the value was / s or higher, it was evaluated as a failure (×). Then, including the previous evaluation of pressing strength, if all evaluations passed, it was marked as '〇', if one of them failed, it was marked as '△', and if both failed, it was marked as '×'. The results are shown in Table 1.

[0063] [Charpy impact test (with notch)] The Charpy impact strength of notched test covers was measured in accordance with ISO 179 / 1eA. Notched test specimens (notch tip radius rN of 0.25 mm ± 0.05 mm) obtained by injection molding were prepared, and their impact strength was measured. The results are shown in Table 1.

[0064] As can be seen from the results above, by including acrylic acid ester along with polyarylene sulfide resin as the resin that forms the sealing material, a lid structure with excellent sealing (airtightness) and adhesion can be realized. [Explanation of symbols]

[0065] 1, 2: Terminal members, 1a, 2a: Flange portion, 3: Sealing plate, 3a: Flange portion, 3b: Mounting hole, 4: Sealing material, 4a: Flange gripping portion, 4b: Flange gripping portion, 5: Movable type, 6: Fixed type, 7: Molten resin, 8: Sprue runner.

Claims

1. A lid for sealing a battery container having an opening, Terminal member and A sealing plate having mounting holes for attaching the terminal member, The terminal member is attached to the mounting hole of the sealing plate and sealed with a sealing material, The sealing material contains a polyarylene sulfide resin as a thermoplastic resin and also contains an acrylic acid ester. The terminal member has a hydroxyl group-containing coating on its outer surface, and the sealing plate has a hydroxyl group-containing coating on the inner wall surface of the mounting hole. A cover characterized in that the terminal member is sealed in the mounting hole of the sealing plate via the sealing material.

2. The lid according to claim 1, wherein the sealing material contains 0.1% by mass or more and 10% by mass or less of an acrylic acid ester.

3. The lid according to claim 2, wherein the acrylic acid ester is one or more selected from the group consisting of methyl acrylate, ethyl acrylate, butyl acrylate, 2-dimethylaminoethyl acrylate, and 2-hydroxyethyl acrylate.

4. The lid according to claim 1, wherein the hydroxyl group-containing film has an oxygen content of 0.1% by mass or more and 50% by mass or less in the surface layer up to a depth of 3 μm from the outermost surface, as measured by EPMA.

5. The lid according to claim 1, wherein the sealing material contains one or more polyolefins selected from the group consisting of polyethylene and polypropylene.

6. The lid according to claim 5, wherein the sealing material contains 0.1% by mass or more and 20% by mass or less of polyolefin.

7. The lid according to claim 1, wherein the sealing material contains polydimethylsiloxane as an additive.

8. A method for manufacturing the lid described in claim 1, A method for manufacturing a lid, characterized by arranging the sealing plate and the terminal member in a mold, leaving a gap between the mounting hole of the sealing plate and the terminal member, and injecting a resin that forms the sealing material, thereby sealing the terminal member to the mounting hole of the sealing plate via the sealing material.

9. An electrode body having a positive electrode and a negative electrode, A battery container having an opening and housing the electrode body, A sealed battery characterized by comprising a lid according to claim 1 for closing the aforementioned opening.

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