Lead wire for non-aqueous electrolyte battery, and non-aqueous electrolyte battery

Abstract

A lead wire for a nonaqueous electrolyte battery according to the present disclosure is provided with: a conductor; and one or more layers of insulating films that cover at least a portion of the outer peripheral surface of the conductor, the conductor having a conductor coating that covers at least a portion of the surface, the conductor coating containing a metal element and a trivalent chromium compound containing chromium hydroxide, the ratio of the number of chromium atoms contained in the chromium hydroxide to the number of chromium atoms contained in the trivalent chromium compound in the outermost surface of the conductor coating film is 0.40-0.85, and the insulating film has an innermost layer laminated on the surface of the conductor coating film. The innermost layer is mainly composed of a resin component containing maleic anhydride-modified polypropylene, and the acid modification rate of the resin component is 0.02 mass% or more and 0.50 mass% or less.

Description

Technical Field

[0001] This disclosure relates to leads for non-aqueous electrolyte batteries and non-aqueous electrolyte batteries. Background Technology

[0002] With the miniaturization and weight reduction of electronic devices, there are also requirements for miniaturization and weight reduction of electrical components used in these devices, such as batteries and capacitors. Therefore, for example, non-aqueous electrolyte batteries have been adopted, which use a bag as a sealed container and seal a non-aqueous electrolyte, a positive electrode, and a negative electrode inside. As the non-aqueous electrolyte, electrolytes are used that are prepared by dissolving fluorine-containing lithium salts such as LiPF6 and LiBF4 in propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.

[0003] Sealed containers require properties that prevent the permeation of electrolytes and gases, as well as the infiltration of moisture from the outside. Therefore, laminated films made of resin coated with metal layers such as aluminum foil are used as the material for sealed containers, and the ends of two laminated films are heat-fused together to form a sealed container.

[0004] One end of the sealed container is designed as an opening, and a non-aqueous electrolyte, a positive electrode plate, a negative electrode plate, and a separator are sealed inside. Furthermore, lead conductors, one end of which is connected to the positive and negative electrode plates, are arranged to extend from the inside of the sealed container to the outside. Finally, the opening of the sealed container is closed by heat sealing (thermal fusion welding), and the sealed container is bonded to the lead conductors to secure the opening. This final heat-fused portion is called the sealing section.

[0005] An insulating film is applied to the portion of the lead conductor corresponding to the sealing portion. A lead with both an insulating film and a lead conductor is called a lead (tab lead) for a non-aqueous electrolyte battery. The container and the lead conductor are bonded together (thermal fusion) using this insulating film. Therefore, the insulating film must not cause a short circuit between the metal layer of the container and the lead conductor, and it must maintain the adhesion between the lead conductor and the container.

[0006] As for the electrode leads, as a prior art, for example, a non-aqueous electrolyte battery with leads having the following features: different metals are used in the conductors of the positive electrode connection lead and the conductors of the negative electrode connection lead, and an insulating layer that does not melt at the heat-sealing temperature of the sealed bag is provided for the insulation of the leads (see Patent Document 1).

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 9-265974 Summary of the Invention

[0010] The lead wire for a non-aqueous electrolyte battery disclosed herein comprises: a conductor; and an insulating film having one or more layers covering at least a portion of the outer peripheral surface of the conductor, the conductor having a conductor film covering at least a portion of the covered surface, the conductor film containing a trivalent chromium compound including chromium hydroxide and a metallic element, wherein the ratio of the number of chromium atoms in the chromium hydroxide to the number of chromium atoms in the trivalent chromium compound in the outermost surface of the conductor film is 0.40 or more and 0.85 or less, the insulating film having an innermost layer stacked on the surface of the conductor film, the innermost layer being primarily composed of a resin component comprising maleic anhydride-modified polypropylene, the acid modification rate of the resin component being 0.02% by mass or more and 0.50% by mass or less. Attached Figure Description

[0011] Figure 1 This is a perspective view of a lead wire for a non-aqueous electrolyte battery according to one embodiment of the present disclosure.

[0012] Figure 2 This is a partial cross-sectional view of a lead wire for a non-aqueous electrolyte battery according to one embodiment of the present disclosure.

[0013] Figure 3 This is a perspective view showing an example of a non-aqueous electrolyte battery with leads for a non-aqueous electrolyte battery according to an embodiment of the present disclosure.

[0014] Figure 4 yes Figure 3 A thickness-direction longitudinal section view of a non-aqueous electrolyte battery. Detailed Implementation

[0015] [The problem this disclosure aims to solve]

[0016] Even with such tab leads, where the adhesion is sufficient immediately after sealing the opening of the container, moisture can easily seep through the seal over time. This seeping moisture reacts with the non-aqueous electrolyte sealed inside the container to produce hydrofluoric acid. Hydrofluoric acid easily corrodes the metal lead conductors, potentially causing delamination at the conductor-insulating film interface. Therefore, improved resistance to non-aqueous electrolytes is required in tab leads.

[0017] The purpose of this disclosure is to provide leads for non-aqueous electrolyte batteries that exhibit excellent resistance to non-aqueous electrolytes in non-aqueous electrolyte batteries.

[0018] [Effects of this disclosure]

[0019] According to this disclosure, a lead wire for a non-aqueous electrolyte battery can be provided that exhibits excellent resistance to non-aqueous electrolytes in non-aqueous electrolyte batteries.

[0020] [Description of embodiments of this disclosure]

[0021] First, embodiments of this disclosure will be described.

[0022] The lead wire (1) for a non-aqueous electrolyte battery disclosed herein comprises: a conductor; and an insulating film having one or more layers covering at least a portion of the outer peripheral surface of the conductor, the conductor having a conductor film covering at least a portion of the covered surface, the conductor film containing a trivalent chromium compound including chromium hydroxide and a metallic element, wherein the ratio of the number of chromium atoms in the chromium hydroxide in the outermost surface of the conductor film to the number of chromium atoms in the trivalent chromium compound is 0.40 or more and 0.85 or less, the insulating film having an innermost layer stacked on the surface of the conductor film, the innermost layer having a resin component comprising maleic anhydride-modified polypropylene as the main component, the acid modification rate of the resin component being 0.02% by mass or more and 0.50% by mass or less.

[0023] In this lead wire for a non-aqueous electrolyte battery, the conductor is coated with a conductor film containing a trivalent chromium compound including chromium hydroxide and a metallic element. This suppresses delamination at the interface between the conductor and the insulating film caused by corrosion of the conductor by hydrofluoric acid generated from the hydrolysis of the non-aqueous electrolyte. Furthermore, the innermost layer laminated on the surface of the conductor film is primarily composed of a resin component containing maleic anhydride-modified polypropylene, wherein the acid modification rate of the resin component is 0.02% by mass or more and 0.50% by mass or less, thereby ensuring good adhesion between the innermost layer and the conductor film.

[0024] Furthermore, the ratio of the number of chromium atoms in the chromium hydroxide to the number of chromium atoms in the trivalent chromium compound on the outermost surface of the conductive coating is 0.40 or more and 0.85 or less. As a result, the conductive coating has a sufficient amount of hydrogen bonds with the maleic anhydride-modified polypropylene in the innermost layer, and the mechanical strength of the conductive coating becomes good, thus improving the adhesion strength between the conductor and the insulating film. On the other hand, regarding the outermost surface of the conductive coating, since the ratio of the number of chromium atoms in the chromium hydroxide to the number of chromium atoms in the trivalent chromium compound on the outermost surface of the conductive coating is 0.40 or more and 0.85 or less, the amount of hydroxyl groups on the surface is less compared to an untreated conductor surface that can be considered to be approximately 100% coated with hydroxide due to the adhesion of moisture from the atmosphere. In contrast, by setting the acid modification rate of the resin component, which is the main component of the innermost layer, to 0.02% by mass or more and 0.50% by mass or less, the frequency of hydrogen bond formation between the hydroxyl groups on the conductor surface and the maleic anhydride modified groups of the resin component can be kept within a good range, thereby further improving the adhesion strength between the conductor and the insulating film.

[0025] Therefore, the leads for this non-aqueous electrolyte battery exhibit excellent resistance to the non-aqueous electrolyte of the non-aqueous electrolyte battery.

[0026] The ratio of the number of chromium atoms in the chromium hydroxide contained in the outermost surface of the conductor film to the number of chromium atoms contained in the trivalent chromium compound is calculated using X-ray photoelectron spectroscopy (hereinafter also referred to as "XPS").

[0027] The term "at the outermost surface of the conductor film" refers to the region up to the detection depth that can be determined using the X-ray photoelectron spectroscopy method for any surface; specifically, it refers to the region extending from any surface into the depth direction up to approximately 5 nm.

[0028] Furthermore, in this disclosure, "main ingredient" refers to an ingredient with a content of more than 50% by mass.

[0029] (2) In (1), the metal element may also be nickel, aluminum, copper, or a combination thereof. By including nickel, aluminum, copper, or a combination thereof as metal elements in the conductor coating, the conductivity of the conductor can be further improved.

[0030] (3) In either (1) or (2), the conductor coating may also contain a calcium compound, a fluorine compound, or a combination thereof. The presence of a calcium compound in the conductor coating improves the stability of the conductor coating against the decomposition products of the non-aqueous electrolyte components in the non-aqueous electrolyte battery when the lead wire for the non-aqueous electrolyte battery is used, thus providing excellent corrosion resistance. The presence of a fluorine compound in the conductor coating promotes the formation of a stable passivation film, further enhancing corrosion resistance.

[0031] (4) In any of (1) to (3), the average thickness of the conductor film may be 1 nm or more and 50 nm or less. With the average thickness of the conductor film being 1 nm or more and 50 nm or less, the conductor has good corrosion resistance.

[0032] (5) In any of (1) to (4), the acid modification rate of the resin component may be 0.10% by mass or more and 0.50% by mass or less. By having the acid modification rate of the resin component be 0.10% by mass or more and 0.50% by mass or less, the bonding strength between the conductor and the insulating film can be further improved.

[0033] (6) In any of (1) to (5), the average thickness of the insulating film may be 0.05 mm or more and 0.50 mm or less. With the average thickness of the insulating film being 0.05 mm or more and 0.50 mm or less, the gap between the insulating film and the sealed container can be fully filled, and the amount of water seeping into the interior of the non-aqueous electrolyte battery through the insulating film from the atmosphere can be reduced.

[0034] (7) In any of (1) to (6), the average thickness of the innermost layer may be 0.01 mm or more and 0.25 mm or less. By having the average thickness of the innermost layer be 0.01 mm or more and 0.25 mm or less, the adhesion to the conductor can be improved, and the amount of water that seeps into the interior of the non-aqueous electrolyte battery through the insulating film from the atmosphere can be suppressed.

[0035] (8) In any of (1) to (7), the conductor may be nickel, nickel-plated metal, nickel-phosphorus alloy metal, aluminum, or aluminum alloy. By using nickel, nickel-plated metal, nickel-phosphorus alloy metal, aluminum, or aluminum alloy as the conductor, the conductivity, withstand potential, etc., can be improved.

[0036] (9) In any of (1) to (8), it may also be that, in the photoelectron spectrum of the outermost surface of the conductor film obtained by X-ray photoelectron spectroscopy, the difference A between the photoelectron intensity at 577.3 (eV) and the background is regarded as the number of chromium atoms contained in chromium hydroxide (III), the difference B between the photoelectron intensity at 576.1 (eV) and the background is regarded as the number of chromium atoms contained in chromium oxide (III), the difference C between the photoelectron intensity at 579.8 (eV) and the background is regarded as the number of chromium atoms contained in chromium fluoride (III), and the ratio of the number of chromium atoms contained in the chromium hydroxide to the number of chromium atoms contained in the trivalent chromium compound is set as A / (A+B+C).

[0037] That is, when the photoelectron spectrum of the conductive film is obtained by X-ray photoelectron spectroscopy with the horizontal axis set to the binding energy of the electron relative to the atomic nucleus and the vertical axis set to the photoelectron intensity, the ratio of the number of chromium atoms contained in the chromium hydroxide in the outermost surface of the conductive film to the number of chromium atoms contained in the trivalent chromium compound can be calculated as follows, thereby concisely and accurately determining the state of the outermost surface of the conductive film.

[0038] Regarding the peak positions in the Cr2p3 energy spectrum obtained by XPS analysis, based on "Applied Surface Science 553 (2021) 149437", chromium(III) hydroxide (Cr(OH)3) is considered to be 577.3 eV, and chromium(III) oxide (Cr2O3) is considered to be 576.1 eV. Furthermore, based on "Surf. Interface Anal. 23 (1995) 887", chromium(III) fluoride (CrF3) is considered to be 579.8 eV.

[0039] Specifically, the photoelectron spectrum of the conductor coating is determined by following these steps.

[0040] [1] Binding energy correction

[0041] In the X-ray photoelectron spectroscopy (XPS) determination of the photoelectron spectrum of the conductive film, the measurement interval of the horizontal axis was set to 0.1 eV. First, the photoelectron spectrum of C1s was measured from 278 eV to 298 eV. Then, the binding energy of the horizontal axis was corrected by addition and subtraction, with the binding energy of the maximum peak in the obtained C1s range being 284.8 eV. The same correction was performed for other elements (Cr2p3) as for C1s.

[0042] [2] Smoothing

[0043] The measurement range of the Cr2p3 energy spectrum was set to 582 eV–570 eV (with a background range of 581 eV–572 eV). The photoelectron intensities of chromium(III) hydroxide, chromium(III) oxide, and chromium(III) fluoride were set as the average of the photoelectron intensities at the measurement points in the Cr2p3 energy spectrum and the photoelectron intensities at the measurement intervals before and after them. The vertical axis of the obtained photoelectron energy spectrum is a relative value, expressed as the relative value when the maximum value of the measurement range is set to 1.

[0044] [3] Calculation of A / (A+B+C)

[0045] In the analysis of the energy spectra of chromium(III) hydroxide, chromium(III) oxide, and chromium(III) fluoride, the baseline was set as a straight line with the two ends of the baseline set at, for example, 581 eV and 572 eV. Then, the values ​​obtained by subtracting the baseline intensity at the peak position from the photoelectron intensities at 577.3 eV, 576.1 eV, and 579.8 eV were designated as A, B, and C. Then, A / (A+B+C) was calculated as the ratio of the number of chromium atoms contained in the chromium hydroxide to the number of chromium atoms contained in the trivalent chromium compound.

[0046] (10) In addition, the non-aqueous electrolyte battery of the present disclosure comprises: a sealed container; a plurality of leads for the non-aqueous electrolyte battery configured to extend from the interior to the exterior of the sealed container; and a non-aqueous electrolyte.

[0047] This non-aqueous electrolyte battery, by having multiple leads for the non-aqueous electrolyte battery, can suppress the peeling of the conductor and the insulating film, thereby improving the sealing performance.

[0048] [Details of the embodiments disclosed herein]

[0049] The following provides a detailed description of the leads and non-aqueous electrolyte batteries for batteries disclosed herein.

[0050] Lead wires for non-aqueous electrolyte batteries

[0051] Figure 1 This is a perspective view of a lead wire for a non-aqueous electrolyte battery according to one embodiment of the present disclosure. Figure 2 This is a partial cross-sectional view of a lead wire for a non-aqueous electrolyte battery according to one embodiment of this disclosure. Figure 1 and Figure 2 As shown, the lead 1 for the non-aqueous electrolyte battery includes: a conductor 3; and an insulating film 5 having one or more layers covering at least a portion of the outer peripheral surface of the conductor 3. Furthermore, the conductor 3, having one end 4a and another end 4b, has a conductor film 9 covering at least a portion of its surface. In this embodiment, the insulating film 5 has: an innermost layer 6 stacked on the surface of the conductor 3; a first insulating layer 8 stacked on the outermost surface of the insulating film 5; and a second insulating layer 7 stacked on the inner surface of the first insulating layer 8. It should be noted that the conductor 3 corresponds to the lead conductor.

[0052] (conductor)

[0053] Conductor 3 is connected to the electrodes of a non-aqueous electrolyte battery. From the viewpoint of conductivity, the materials used for conductor 3 can include, for example, metallic materials such as aluminum, titanium, nickel, copper, aluminum alloys, titanium alloys, nickel alloys, and copper alloys; nickel-plated metals obtained by plating these metallic materials with nickel; and nickel-phosphorus alloys. Among these, the material used to form conductor 3, which is connected to the negative electrode of the non-aqueous electrolyte battery, can be nickel, nickel-plated metal, or nickel-phosphorus alloy. On the other hand, from the viewpoints of potential resistance, conductivity, and cost, the material used to form conductor 3, which is connected to the positive electrode, can be aluminum or aluminum alloys.

[0054] The lower limit for the average thickness of conductor 3 can be 0.10 mm. When the average thickness of conductor 3 is 0.10 mm or more, sufficient current can be provided for practical use as a battery. Furthermore, the lower limit for the average thickness of conductor 3 can be 0.15 mm or 0.20 mm. On the other hand, the upper limit for the average thickness of conductor 3 is not particularly limited, and can be appropriately set according to the capacity of the non-aqueous electrolyte battery. For example, the upper limit for the average thickness can be 5.00 mm. When the average thickness of conductor 3 is 5.00 mm or less, resistive heating at the lead portion can be suppressed even during rapid charging and discharging of the leads. Furthermore, the upper limit for the average thickness of conductor 3 can be 4 mm. It should be noted that the "average thickness" of conductor 3 refers to the average value of the thickness measurements at 10 points. Hereinafter, "average thickness" has the same meaning.

[0055] (Conductor coating)

[0056] A conductive coating 9 covers at least a portion of the surface of the conductor 3. The conductive coating 9 contains a trivalent chromium compound including chromium hydroxide and a metallic element. By coating the conductor 3 with a conductive coating containing a trivalent chromium compound including chromium hydroxide and a metallic element, the conductor 3 exhibits good corrosion resistance.

[0057] The metallic element can be nickel, aluminum, copper, or a combination thereof. By including nickel, aluminum, copper, or a combination thereof as metallic elements in the conductor film 9, the conductivity of the conductor 3 can be further improved.

[0058] In the outermost surface of the conductive film 9, the lower limit for the ratio of the number of chromium atoms contained in chromium hydroxide to the number of chromium atoms contained in the trivalent chromium compound is 0.40, or it can be 0.41. If the ratio of the number of chromium atoms in the chromium hydroxide is less than 0.40, the conductive film 9 cannot form a sufficient amount of hydrogen bonds with the maleic anhydride-modified polypropylene in the innermost layer 6, and the adhesion strength between the conductor 3 and the insulating film 5 may become insufficient. On the other hand, the upper limit for the ratio of the number of chromium atoms in the chromium hydroxide is 0.85, or it can be 0.84. When the ratio of the number of chromium atoms in the chromium hydroxide exceeds 0.85, the mechanical strength of the conductive film 9 decreases, and the adhesion strength between the conductor 3 and the insulating film 5 may become insufficient. By having the ratio of the number of chromium atoms contained in the chromium hydroxide within the specified range, the conductor coating has a sufficient amount of hydrogen bonds with the maleic anhydride-modified polypropylene in the innermost layer, and the mechanical strength of the conductor coating becomes good, thus improving the adhesion strength between the conductor and the insulating film.

[0059] The ratio of the number of chromium atoms contained in chromium hydroxide on the outermost surface of the conductor film 9 to the number of chromium atoms contained in the trivalent chromium compound is as described above. In the photoelectron spectrum of the outermost surface of the conductor film, the difference A between the photoelectron intensity at 577.3 (eV) and the background is regarded as the number of chromium atoms contained in chromium hydroxide (III), the difference B between the photoelectron intensity at 576.1 (eV) and the background is regarded as the number of chromium atoms contained in chromium oxide (III), and the difference C between the photoelectron intensity at 579.8 (eV) and the background is regarded as the number of chromium atoms contained in chromium fluoride (III). This ratio can be calculated by A / (A+B+C).

[0060] The conductor coating 9 may further contain calcium compounds, fluorine compounds, or combinations thereof. The presence of calcium compounds in the conductor coating 9 improves the stability of the decomposition products of the non-aqueous electrolyte components in the non-aqueous electrolyte battery when the lead 1 is used in the non-aqueous electrolyte battery, thus providing excellent corrosion resistance. The presence of fluorine compounds in the conductor coating 9 promotes the formation of a stable passivation film, further enhancing corrosion resistance. Examples of calcium compounds include calcium oxide, calcium hydroxide, calcium carbonate, calcium chromate, calcium chromate dihydrate, anhydrous calcium chromate, and calcium aluminate compounds. Examples of fluorine compounds include calcium fluoride, chromium fluoride, aluminum fluoride, and copper fluoride. The calcium and fluorine compounds in the conductor coating 9 can be identified using XPS.

[0061] The lower limit of the average thickness of the conductor film 9 can be 1 nm or 3 nm. With an average thickness of 1 nm or more, sufficient corrosion resistance of the conductor 3 can be obtained. On the other hand, the upper limit of the average thickness of the conductor film 9 can be 50 nm or 20 nm. With an average thickness of 50 nm or less, the decrease in density caused by the formation of cracks in the conductor film 9 can be suppressed, and corrosion resistance can be maintained better. The average thickness of the conductor film 9 can be determined by using XPS to analyze the elements present on the surface of the conductor 3 coated with the conductor film 9.

[0062] (Insulating film)

[0063] An insulating film 5 is used as the insulating film for the lead 1 of a non-aqueous electrolyte battery. The insulating film 5 has one or more insulating layers, which are laminated on the outer peripheral surface of the conductor 3 in such a way that they cover at least a portion of the outer peripheral surface of the conductor 3. By having one or more insulating layers 3, the insulating film 5 can be endowed with various functions according to the purpose of the lead 1 for the non-aqueous electrolyte battery. The lead 1 for the non-aqueous electrolyte battery of this embodiment includes an insulating film 5 having three insulating layers 3.

[0064] The lower limit of the average thickness of the insulating film 5 can be 0.05 mm. With an average thickness of 0.05 mm or more, the insulating film 5 can reliably seal the gap between it and the sealing container 11, created by the height difference in thickness of the conductor 3. Furthermore, the lower limit of the average thickness of the insulating film 5 can be 0.08 mm or 0.10 mm. On the other hand, the upper limit of the average thickness of the insulating film 5 can be 0.50 mm. With an average thickness of 0.50 mm or less, the amount of water seeping into the interior of the non-aqueous electrolyte battery 10 through the insulating film 5 from the atmosphere can be reduced, suppressing the degradation of the non-aqueous electrolyte battery. Furthermore, the upper limit of the average thickness of the insulating film 5 can be 0.40 mm or 0.30 mm. Here, in this disclosure, the average thickness of the insulating film 5 is the average value of the measured thickness at 10 points on the surface with the largest area on the outer peripheral surface of the insulating film 5.

[0065] In this embodiment, the insulating film 5 has: an innermost layer 6, which is stacked on the surface of the conductor 3; a first insulating layer 8, which is stacked on the outermost surface of the insulating film 5; and a second insulating layer 7, which is stacked on the inner surface of the first insulating layer 8.

[0066] (Innermost layer)

[0067] The innermost layer 6 is stacked on the surface of the conductor film 9. The insulating film 5, by having the innermost layer 6, can inhibit the corrosion of the conductor 3.

[0068] The innermost layer 6 is mainly composed of a resin component containing maleic anhydride-modified polypropylene (maleic anhydride-modified PP). Because the innermost layer 6 is mainly composed of a resin component containing maleic anhydride-modified polypropylene, it has good adhesion to the conductor film 9.

[0069] The lower limit of the acid modification rate of the resin component is 0.02% by mass, or it can be 0.10% by mass. When the acid modification rate of the resin component is 0.02% by mass or more, the adhesion between the innermost layer 6 and the conductor film 9 can be improved, resulting in sufficient resistance to non-aqueous electrolytes. On the other hand, the upper limit of the acid modification rate of the resin component is 0.50% by mass, or it can be 0.40% by mass. When the acid modification rate of the resin component is 0.50% by mass or less, the maleic anhydride modifying groups can suppress the corrosion of the conductor 3, resulting in good corrosion resistance.

[0070] The acid modification rate was calculated as follows: by infrared spectroscopy transmission method (FT-IR), based on 1710 cm⁻¹. －1 The mass of the carboxyl group was determined by the peak area and converted based on an appropriate standard curve according to the average thickness of the innermost 6 layers.

[0071] The melting point of maleic anhydride-modified polypropylene can be either above 130°C and below 170°C, or above 130°C and below 150°C. If the melting point of maleic anhydride-modified polypropylene is below 130°C, its heat resistance may decrease. On the other hand, if the melting point of maleic anhydride-modified polypropylene exceeds 170°C, the large amount of heat required to melt it may prevent it from melting sufficiently, potentially resulting in insufficient adhesion of the innermost layer 6 to the conductor 3.

[0072] The lower limit for the content of maleic anhydride-modified polypropylene in the innermost layer 6 can be either 0.1% by mass or 0.5% by mass. If the content of maleic anhydride-modified polypropylene is less than 0.1% by mass, it may be impossible to obtain practically sufficient material properties.

[0073] In the innermost layer 6, to the extent that it does not impair the effects of this disclosure, the resin component may contain a thermoplastic resin other than maleic anhydride-modified polypropylene. Examples of thermoplastic resins other than maleic anhydride-modified polypropylene include, for example, polyolefins such as polypropylene and polyethylene. Furthermore, the innermost layer 6 may also contain other known additives. Examples of known additives include, for example, antioxidants, flame retardants, tackifiers, lubricants, fillers, crystallization promoters, and colorants.

[0074] The lower limit of the average thickness of the innermost layer 6 can be 0.01 mm. With an average thickness of 0.01 mm or more, sufficient adhesion to the conductor 3 can be obtained. Furthermore, the lower limit of the average thickness of the innermost layer 6 can also be 0.02 mm or 0.03 mm. On the other hand, the upper limit of the average thickness of the innermost layer 6 can be 0.25 mm. With an average thickness of 0.25 mm or less, the amount of water seeping into the interior of the non-aqueous electrolyte battery through the insulating film 5 from the atmosphere can be reduced, suppressing battery degradation. Furthermore, the upper limit of the average thickness of the innermost layer 6 can also be 0.22 mm or 0.20 mm. Here, in this disclosure, the average thickness of the innermost layer 6 is the average of the thickness measurements at 10 points on the surface with the largest area on the outer periphery of the innermost layer 6.

[0075] (First insulating layer)

[0076] The first insulating layer 8 is positioned furthest from the conductor 3 and is formed of a thermoplastic resin. The first insulating layer 8 is laminated on the outermost surface of the insulating film 5 and on the surface of the second insulating layer 7. The first insulating layer 8 may be primarily composed of a resin that readily melts at the heat-sealing temperature during heat sealing (heat fusion) of the opening to be sealed into the container, or it may be primarily composed of a polyolefin.

[0077] Examples of polyolefins include polypropylene, polyethylene, and their derivatives. More specifically, combinations of homopolymer polypropylene, block polypropylene, atactic polypropylene, low-crystallinity polypropylene, low-density polyethylene, linear low-density polyethylene, low-crystallinity ethylene-propylene copolymer, low-crystallinity ethylene-butene copolymer, low-crystallinity ethylene-octene copolymer, and low-crystallinity propylene-ethylene copolymer can be included. The first insulating layer 8 can contain various resins. As a polyolefin, it can be polypropylene, and as polypropylene, it can be atactic polypropylene with a melting point of 120°C or higher and 155°C or lower, and an MFR (Melt Flow Rate) of 3 g / 10 min or higher and 15 g / 10 min or lower. By using atactic polypropylene as the polyolefin, it has the advantage of being able to fully exert its adhesion to the second insulating layer 7 and the innermost resin layer of the sealed container.

[0078] The lower limit for the polyolefin content in the first insulating layer 8 can be 70% by mass. When the polyolefin content becomes less than 70% by mass, it may be impossible to obtain practically sufficient material properties. Furthermore, the lower limit for the polyolefin content in the first insulating layer 8 can be 80% by mass, 90% by mass, or even 100% by mass.

[0079] To the extent that it does not impair the effects of this disclosure, the first insulating layer 8 may contain a thermoplastic resin other than the polyolefin.

[0080] To the extent that it does not impair the effects of this disclosure, the first insulating layer 8 may also contain other known additives. Examples of known additives include, for instance, antioxidants, flame retardants, tackifiers, lubricants, fillers, crystallization promoters, and colorants.

[0081] The lower limit of the average thickness of the first insulating layer 8 can be 25 μm. If the average thickness of the first insulating layer 8 is less than 25 μm, the strength of the first insulating layer 8 may not be sufficiently obtained. Furthermore, the lower limit of the average thickness of the first insulating layer 8 can be 30 μm or 40 μm. On the other hand, the upper limit of the average thickness of the first insulating layer 8 can be 250 μm. If the average thickness of the first insulating layer 8 exceeds 250 μm, the amount of water seeping into the non-aqueous electrolyte battery through the insulating film 5 from the atmosphere increases, which may accelerate battery degradation. Here, in this disclosure, the average thickness of the first insulating layer 8 is the average of the measured thickness values ​​at 10 points on the surface with the largest area on the outer peripheral surface of the first insulating layer 8.

[0082] (Second insulating layer)

[0083] The insulating film 5 may have a second insulating layer 7 between the first insulating layer 8 and the innermost layer 6. The second insulating layer 7 is laminated on the inner surface of the first insulating layer 8. The second insulating layer 7 may contain cross-linked polyolefin or a polyolefin resin with a melting point higher than that of the innermost layer 6. Because the second insulating layer 7 contains cross-linked polyolefin or a polyolefin resin with a melting point higher than that of the innermost layer 6, it is less likely to melt at the heat-sealing temperature when the opening of the sealed container is heat-sealed, thus suppressing short circuits between the metal layer and the conductor of the sealed container.

[0084] Examples of polyolefins in the cross-linked polyolefins include polypropylene, polyethylene, and their derivatives.

[0085] As a high-melting-point polyolefin, it can be high-melting-point polypropylene with a melting point above 155℃, especially homopolymer polypropylene, block polypropylene, thermoplastic olefin elastomer (TPO), etc.

[0086] To the extent that it does not impair the effects of this disclosure, the second insulating layer 7 may contain a thermoplastic resin other than the cross-linked polyolefin, or other known additives. Examples of known additives include, for instance, antioxidants, flame retardants, tackifiers, lubricants, fillers, crystallization promoters, and colorants.

[0087] The lower limit for the average thickness of the second insulating layer 7 can be 25 μm. If the average thickness of the second insulating layer 7 is less than 25 μm, the strength of the second insulating layer 7 may not be sufficiently obtained. Furthermore, the lower limit for the average thickness of the second insulating layer 7 can be 30 μm or 40 μm. On the other hand, the upper limit for the average thickness of the second insulating layer 7 can be 250 μm. If the average thickness of the second insulating layer 7 exceeds 250 μm, the amount of water seeping into the interior of the non-aqueous electrolyte battery through the insulating film 5 from the atmosphere may easily increase. Here, in this disclosure, the average thickness of the second insulating layer 7 is the average of the measured thickness values ​​at 10 points on the surface with the largest area on the outer peripheral surface of the second insulating layer 7.

[0088] [Manufacturing method for leads used in non-aqueous electrolyte batteries]

[0089] The manufacturing method for the leads used in this non-aqueous electrolyte battery is not particularly limited and can be manufactured using known methods.

[0090] First, at least a portion of the conductor's surface is chemically converted (chromate treatment) using a treatment solution to coat the conductor with a film.

[0091] First, for example, degreasing is performed on the peripheral surface of the conductor. Sometimes, oily components adhere to the surface of the conductor during molding; this degreasing is to remove these oily components. Degreasing can be performed by coating or impregnating with organic solvents, surfactants, acids, or alkalis. Next, after cleaning, removing the organic solvents, surfactants, acids, or alkalis, and drying, a liquid primarily composed of chromates is used to chemically convert the metal surface.

[0092] Examples of acidic compounds used in defatting include hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, phosphoric acid, aminosulfonic acid and other inorganic acids, citric acid, gluconic acid, oxalic acid, tartaric acid, formic acid, glycolic acid, EDTA (ethylenediaminetetraacetic acid), and ammonium mercaptoacetate. In addition, examples of alkaline compounds include: sodium salts such as sodium hydroxide (NaOH), sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3), sodium sulfate (Na2SO4·10H2O), and sodium sesquicarbonate (Na2CO3·NaHCO3·2H2O); silicates such as sodium orthosilicate (2Na2O·SiO2, moisture 10%–40%) and sodium metasilicate (2Na2O·SiO2·9H2O); phosphates such as sodium dihydrogen phosphate (NaH2PO4), sodium pyrophosphate (Na4P2O7), disodium hydrogen phosphate (Na2HPO4), sodium hexametaphosphate {(NaPO3)6}, and sodium phosphate (Na3PO4); etc.

[0093] As a method of chemical conversion treatment, the peripheral surface of the conductor is chemically converted by methods such as immersing the conductor in a treatment solution, spraying the treatment solution onto the conductor, or coating the conductor with the treatment solution using a roller coating method, followed by drying. In chemical conversion treatment, at least the coated portion of the insulating film can be treated, but ideally, the entire circumference of the conductor should be treated using methods such as immersion, spraying, or roller coating.

[0094] The treatment solution used for chemical conversion was an aqueous solution containing 5.0 g / L chromium chloride hexahydrate and 170 g / L potassium formate. The treatment solution was subjected to cathodic electrolysis at 45°C and a current density of 10 A / dm³. 2 Under these conditions, the coating is applied to the conductor in 30 seconds. Then, after drying, it is baked at a temperature of 100°C or higher and 300°C or lower to form a conductor coating.

[0095] Next, an insulating film is applied to at least a portion of the outer peripheral surface of the conductor, which is covered by a conductor film. The method for manufacturing the insulating film is not particularly limited. For example, a resin composition containing the resin components and additives for each insulating layer can be mixed using known mixing equipment such as an open mill, a pressure kneader, a single-screw mixer, or a twin-screw mixer. Then, in the case of producing each insulating layer, film-like insulating layers can be produced by extrusion molding such as T-die forming or blow molding. The insulating layers are then overlapped and bonded together using hot rolling to form an insulating film. Alternatively, multiple insulating layers can be formed simultaneously using co-extrusion-based blow molding or T-die molding. An extrusion lamination method in which molten resin is laminated onto a single-layer film can also be used. The film-like insulating film is cut to a predetermined size and bonded to both sides of the conductor by heat and pressure bonding, thereby covering at least a portion of the outer peripheral surface of the conductor.

[0096] In addition to extrusion molding, insulation layers can also be produced through injection molding. In injection molding, if resin is injected after the conductor is assembled into the mold, the periphery of the conductor can be covered, and two-color molding can be used when forming multiple layers.

[0097] The leads for this non-aqueous electrolyte battery exhibit excellent resistance to the non-aqueous electrolyte of non-aqueous electrolyte batteries.

[0098] <Non-aqueous electrolyte batteries>

[0099] The non-aqueous electrolyte battery 10 includes the aforementioned lead 1 for the non-aqueous electrolyte battery and a non-aqueous electrolyte. Examples of non-aqueous electrolyte batteries include secondary batteries such as lithium-ion batteries.

[0100] Figure 3 This is a perspective view showing an example of a non-aqueous electrolyte battery equipped with the leads for a non-aqueous electrolyte battery. Furthermore, Figure 4 This is a partial cross-sectional view schematically illustrating one embodiment of a non-aqueous electrolyte battery. Figure 3 and Figure 4The non-aqueous electrolyte battery (non-aqueous electrolyte secondary battery) 10 shown includes: a plate-shaped positive electrode (not shown), a plate-shaped negative electrode, and a non-aqueous electrolyte; a sealed container 11; and a plurality of, specifically, two, non-aqueous electrolyte battery leads 1. The non-aqueous electrolyte battery leads 1 are the aforementioned non-aqueous electrolyte battery leads. As described above, the insulating film 5 of the non-aqueous electrolyte battery leads 1 of this embodiment has an innermost layer 6, a second insulating layer 7, and a first insulating layer 8. The non-aqueous electrolyte battery 10 has a generally square sealed container 11 and two non-aqueous electrolyte battery leads 1 extending from the inside of the sealed container 11 to the outside. The conductor 3 is connected to the sealed container 11 at the sealing portion 13 of the sealed container 11 through the insulating film 5. The sealed container 11 is a container that contains the positive electrode, negative electrode, separator, and non-aqueous electrolyte in a sealed state.

[0101] A positive and negative electrode (not shown) are stacked together with a separator to form a stacked electrode assembly. This stacked electrode assembly and a non-aqueous electrolyte are housed in a sealed container 11. Within the sealed container 11, the stacked electrode assembly is immersed in the electrolyte. The sealed container 11 is formed of sheets, as described later. Within the sealed container 11, the sealing portions 13 around two sheets or a bent sheet are thermally fused together, thereby achieving a sealed state.

[0102] like Figure 4 As shown, in the two non-aqueous electrolyte battery leads 1, one non-aqueous electrolyte battery lead 1 is configured such that one end 4a of its conductor 3 protrudes from the sealed container 11, and the other end 4b is connected to the positive electrode inside the sealed container 11. The other non-aqueous electrolyte battery lead 1 is configured such that one end 4a of its conductor 3 protrudes from the sealed container 11, and the other end 4b is connected to the negative electrode inside the sealed container 11.

[0103] The sealed container 11 is not stacked on either end of the conductor 3, i.e., one end 4a and the other end 4b. One end 4a of the conductor 3 protrudes from the sealed container 11. On the other hand, at the other end 4b of the conductor 3 of the non-aqueous electrolyte battery lead 1 at the positive electrode, an internal connection lead 14 is connected via a solder part 15, and this internal connection lead 14 is connected to the positive electrode (not shown). Similarly, at the other end 4b of the conductor 3 of the non-aqueous electrolyte battery lead 1 at the negative electrode, an internal connection lead 14 is connected via a solder part 15, and this internal connection lead 14 is connected to the negative electrode (not shown). Figure 4 As shown, the middle portion of these non-aqueous electrolyte battery leads 1 is held as a sheet of a sealing container 11 through an insulating film 5. In this portion, the sealing container 11 is thermally fused with the first insulating layer 8 of the plurality of non-aqueous electrolyte battery leads 1.

[0104] The positive and negative electrodes are typically laminates on the surface of a current collector such as a metal foil, with a layer of active material containing active material stacked on top. The positive and negative electrodes are usually plate-shaped, but can also be other shapes.

[0105] The insulating element is typically an insulating and porous membrane. It is impregnated with a non-aqueous electrolyte.

[0106] Non-aqueous electrolytes contain a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent.

[0107] like Figure 4 As shown, the sealing container 11 is composed of a sheet formed by sequentially stacking an innermost resin layer 27, a metal layer 25, and an outermost resin layer 26. Furthermore, regarding the sealing container 11, two sheets are overlapped, and the three sides other than the side through which the conductor passes are heat-sealed to form a sealing portion 13. In addition, at the sealing portion 13, the conductors 3 of each non-aqueous electrolyte battery lead 1 are bonded to the sealing container 11 through an insulating film 5. At this portion, the innermost resin layer 27 of the sealing container 11 is heat-fused to the first insulating layer 8 of each non-aqueous electrolyte battery lead 1.

[0108] The innermost resin layer 27 is directly laminated onto the inner surface of the metal layer 25. The innermost resin layer 27, located inside the sealed container 11, can be an insulating resin that is insoluble in non-aqueous electrolytes and melts upon heating. For example, polyolefins, acid-modified polyolefins, or acid-modified styrene-based elastomers can be used as the innermost resin layer 27. Polypropylene is preferably used as the innermost resin layer 27. Furthermore, the average thickness of the innermost resin layer 27 can range from 10 μm to 500 μm.

[0109] The metal layer 25 has functions such as improving the strength of the sealing container 11 and preventing water vapor, oxygen, light, etc., from seeping into the battery. The metal layer 25 is formed of a metal such as aluminum foil. The metal layer 25 is primarily composed of a metal. Examples of such metals include aluminum, copper, stainless steel, and titanium, with aluminum being preferred. While the metal layer 25 is substantially formed of a metal, it may also contain additives other than metals. The metal layer 25 is film-like and can be formed from a metal foil or an aluminum alloy foil. Furthermore, the average thickness of the metal layer 25 can be between 10 μm and 50 μm.

[0110] The outermost resin layer 26 serves to protect the outer surface of the metal layer 25 and provides insulation. As the outermost resin layer 26 located on the outside of the sealed container, it is typically composed primarily of resin, serving as an insulating material. Examples of resins forming the outermost resin layer 26 include polyethylene terephthalate (PET), polyamide, polyester, polyolefin, epoxy resin, acrylic resin, fluoropolymer, polyurethane, silicone resin, phenolic resin, polyetherimide, polyimide, and mixtures and copolymers thereof. The outermost resin layer 26 may, for example, be composed of multiple layers separated by adhesive layers containing polyethylene terephthalate, polyamide, etc. Furthermore, the average thickness of the outermost resin layer 26 can range from 10 μm to 50 μm.

[0111] In this non-aqueous electrolyte battery 10, as described above, one end 4a of the non-aqueous electrolyte battery lead 1, i.e., one end of the conductor 3, is positioned exposed from the sealing container 11 and sealed by the sealing container 11. Specifically, the non-aqueous electrolyte battery lead 1 is configured such that the innermost resin layer of the sealing container 11 is in direct contact with the insulating film 5 of the non-aqueous electrolyte battery lead 1. Furthermore, with the non-aqueous electrolyte battery lead 1 configured in this way, the innermost resin layer 27 at the sealing portion 13 of the sealing container 11 is thermally fused to the first insulating layer 8 of the non-aqueous electrolyte battery lead 1. Thus, the positive electrode, negative electrode, and separator of the stacked electrode assembly immersed in the non-aqueous electrolyte can be sealed inside the sealing container 11.

[0112] [Manufacturing method of non-aqueous electrolyte battery]

[0113] The method for manufacturing a non-aqueous electrolyte battery according to one embodiment of this disclosure can be appropriately selected from known methods. The method includes, for example, the following steps: preparing leads for the non-aqueous electrolyte battery; preparing a stacked electrode assembly; preparing a non-aqueous electrolyte; and containing the stacked electrode assembly connected to the leads for the non-aqueous electrolyte battery and the non-aqueous electrolyte in a sealing container.

[0114] This non-aqueous electrolyte battery, by having multiple leads for the non-aqueous electrolyte battery, can suppress the peeling of the conductor and the insulating film, thereby improving the sealing performance.

[0115] [Other Implementation Methods]

[0116] The embodiments disclosed herein should be considered illustrative rather than limiting in all respects. The scope of this disclosure is not limited to the configuration of the described embodiments, but is shown by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0117] In the described embodiment, the lead wire for the non-aqueous electrolyte battery has a three-layer insulating film with an innermost layer, a second insulating layer, and a first insulating layer. However, the lead wire for the non-aqueous electrolyte battery may also have a two-layer insulating film without a second insulating layer. Furthermore, the lead wire for the non-aqueous electrolyte battery may also have a multi-layer insulating film with one or more intermediate layers inside the second insulating layer.

[0118] Example

[0119] The present invention will be described in more detail below through embodiments, but the present invention is not limited to the following embodiments.

[0120] [Experiment No. 1]

[0121] (Making of lead conductors)

[0122] The substrate used as the lead conductor was an oxygen-free copper plate (C1020) with a length of 100 mm, a width of 45 mm, and an average thickness of 0.2 mm. As a pretreatment, the substrate was immersed in a sodium hydroxide aqueous solution (40 g / L) at 25°C, with a current density of 1.0 A / dm³. 2 Cathodic electrolytic degreasing was performed. The degreased substrate was then rinsed with running water.

[0123] Next, the cleaned substrate was acid-activated by immersing it in a 10% by mass sulfuric acid aqueous solution at 25°C for 30 seconds. The acid-activated substrate was then rinsed with running water.

[0124] Next, nickel sulfamate tetrahydrate (350 g / L), nickel chloride hexahydrate (30 g / L), and boric acid (30 g / L) were mixed to obtain a nickel plating solution. The acid-activated substrate was immersed in the nickel plating solution at 50°C and a current density of 5.0 A / dm³ was applied. 2 The plating process lasted 120 seconds. The plated substrate was then rinsed with running water, resulting in a lead conductor made of nickel-plated copper (a nickel-plated metal).

[0125] (Formation of the conductor coating)

[0126] A surface treatment solution was obtained by mixing chromium chloride hexahydrate (5.0 g / L) and potassium formate (170 g / L) in pure water. The lead conductor was then immersed in the surface treatment solution at 45°C with a current density of 10 A / dm³. 2 Cathodic electrolysis was performed for 30 seconds. The cathodic-electrolyzed lead conductor was then rinsed with running water and dried in a constant-temperature bath at 100°C for 180 seconds, thereby obtaining a lead conductor with a conductive coating. The ratio of the number of chromium atoms in the chromium hydroxide to the number of chromium atoms in the trivalent chromium compound in the outermost surface of this conductive coating is 0.50.

[0127] (Making of insulating film)

[0128] A double-layered insulating film comprising an innermost layer and a first insulating layer was fabricated. First, resin compositions for the innermost layer and the first insulating layer were prepared using a mixing apparatus.

[0129] (1) Innermost layer

[0130] 100 parts by weight of PrimePolypro F227D (melting point 142℃, MFR 7) manufactured by Prime Polypro as random polypropylene (random PP) and 1 part by weight of POLYBOND 3000 (melting point 157℃, acid modification rate 1.2% by weight) manufactured by SIIgroup as maleic anhydride modified polypropylene were mixed using a twin-screw mixer to obtain a resin composition with an acid modification rate of 0.01% by weight.

[0131] (2) First insulating layer

[0132] The resin composition used as the first insulating layer is random polypropylene: Prime Polypro F227D (MFR 7g / 10 min, melting point 140°C) manufactured by Prime Polypro.

[0133] (3) Fabrication of insulating film

[0134] Next, using a coat hanger-type dual-material, dual-layer T-die film-forming machine equipped with two single-screw extruders, the innermost resin composition was fed into the first extruder, and the first insulating layer resin composition was fed into the second extruder for co-extrusion, thereby obtaining a dual-layer insulating film stacked in the order of innermost resin composition / first insulating layer resin composition. The average thickness of the innermost layer is 50 μm, and the average thickness of the first insulating layer is 100 μm.

[0135] (Fabrication of leads for non-aqueous electrolyte batteries)

[0136] Next, the obtained double-layer insulating film was cut to the specified size and heat-sealed on both sides of the conductor under a mold temperature of 220°C and a surface pressure of 0.2 MPa. This yielded the No.1 lead wire for non-aqueous electrolyte batteries.

[0137] [Experiment No. 2]

[0138] In the fabrication of the insulating film, 100 parts by weight of Prime Polypro F227D (atactic polypropylene) manufactured by Prime Polypro Corporation and 5 parts by weight of POLYBOND 3000 (maleic anhydride modified polypropylene) manufactured by SIIgroup Corporation were used as the materials for the innermost resin composition, resulting in a resin composition with an acid modification rate of 0.06% by weight. In addition, leads for non-aqueous electrolyte batteries were obtained in the same manner as in Experiment No.1.

[0139] [Experiment No. 3]

[0140] In the fabrication of the insulating film, 100 parts by weight of Prime Polypro F227D (random polypropylene) manufactured by Prime Polypro Corporation and 15 parts by weight of POLYBOND 3000 (maleic anhydride modified polypropylene) manufactured by SIIgroup Corporation were used as the materials for the innermost resin composition, resulting in random PP with an acid modification rate of 0.18% by weight. In addition, leads for non-aqueous electrolyte batteries were obtained in the same manner as in Experiment No.1.

[0141] [Experiment No. 4]

[0142] In the fabrication of the insulating film, 100 parts by weight of Prime Polypro F227D (random polypropylene) manufactured by Prime Polypro Corporation and 40 parts by weight of POLYBOND 3000 (maleic anhydride modified polypropylene) manufactured by SIIgroup Corporation were used as the materials for the innermost resin composition, resulting in random PP with an acid modification rate of 0.48% by weight. In addition, leads for non-aqueous electrolyte batteries were obtained in the same manner as in Experiment No.1.

[0143] [Experiment No. 5]

[0144] In the fabrication of the insulating film, 100 parts by weight of Prime Polypro F227D (random polypropylene) manufactured by Prime Polypro Corporation and 50 parts by weight of POLYBOND 3000 (maleic anhydride modified polypropylene) manufactured by SIIgroup Corporation were used as the materials for the innermost resin composition, resulting in random PP with an acid modification rate of 0.60% by weight. In addition, leads for non-aqueous electrolyte batteries were obtained in the same manner as in Experiment No.1.

[0145] [Experiment No. 6]

[0146] In the formation of the conductive coating, the lead conductor after cathode electrolysis is washed with running water and dried in a constant temperature bath at 100°C for 30 seconds, thereby obtaining a lead conductor with a conductive coating in which the ratio of the number of chromium atoms contained in the chromium hydroxide in the outermost surface of the conductive coating to the number of chromium atoms contained in the trivalent chromium compound is 0.83. In addition, a lead for a non-aqueous electrolyte battery is obtained in the same manner as No.3.

[0147] [Experiment No. 7]

[0148] In the formation of the conductive coating, the lead conductor after cathode electrolysis is washed with running water and dried in a constant temperature bath at 80°C for 20 seconds, thereby obtaining a lead conductor with a conductive coating in which the ratio of the number of chromium atoms contained in the chromium hydroxide in the outermost surface of the conductive coating to the number of chromium atoms contained in the trivalent chromium compound is 0.88. In addition, a lead for a non-aqueous electrolyte battery is obtained in the same manner as No.3.

[0149] [Experiment No. 8]

[0150] In the formation of the conductive coating, the lead conductor after cathode electrolysis is washed with running water and dried in a constant temperature bath at 250°C for 3600 seconds, thereby obtaining a lead conductor with a conductive coating in which the ratio of the number of chromium atoms contained in the chromium hydroxide in the outermost surface of the conductive coating to the number of chromium atoms contained in the trivalent chromium compound is 0.38. In addition, a lead for a non-aqueous electrolyte battery is obtained in the same manner as No.3.

[0151] [Experiment No. 9]

[0152] As the substrate for the lead conductor, a flat conductor made of an aluminum plate with a length of 100 mm, a width of 45 mm, and an average thickness of 0.4 mm was used. Then, in the formation of the conductor coating, chromium chloride hexahydrate (5.0 g / L) and potassium formate (170 g / L) were mixed in pure water to obtain a surface treatment solution. The lead conductor was immersed in the surface treatment solution at 45°C and subjected to a current density of 10 A / dm³. 2 Cathodic electrolysis was performed for 10 seconds. The cathodic electrolytic lead conductor was then washed with running water, thereby obtaining a lead conductor with a conductive coating in which the ratio of the number of chromium atoms contained in the chromium hydroxide in the outermost surface of the conductive coating to the number of chromium atoms contained in the trivalent chromium compound was 0.57. Otherwise, a lead for a non-aqueous electrolyte battery was obtained in the same manner as No.3.

[0153] [Experiment No. 10]

[0154] As the substrate for the lead conductor, a flat conductor made of an aluminum plate with a length of 100 mm, a width of 45 mm, and an average thickness of 0.4 mm was used. In the formation of the conductor coating, chromium chloride hexahydrate (5.0 g / L), potassium formate (170 g / L), and potassium fluoride (5.0 g / L) were mixed in pure water to obtain a surface treatment solution. The lead conductor was immersed in the surface treatment solution at 45°C and subjected to a current density of 10 A / dm³. 2 Cathodic electrolysis was performed for 10 seconds. The cathodic electrolytic lead conductor was then washed with running water, thereby obtaining a lead conductor with a conductive coating in which the ratio of the number of chromium atoms contained in the chromium hydroxide in the outermost surface of the conductive coating to the number of chromium atoms contained in the trivalent chromium compound was 0.41. Otherwise, a lead for a non-aqueous electrolyte battery was obtained in the same manner as No.3.

[0155] [Experiment No. 11]

[0156] In the formation of the conductor coating, chromium chloride hexahydrate (5.0 g / L), potassium formate (170 g / L), and calcium chloride (0.5 g / L) were mixed in pure water to obtain a surface treatment solution. The lead conductor was immersed in the surface treatment solution at 45°C and subjected to a current density of 10 A / dm³. 2 Cathodic electrolysis was performed for 30 seconds. The cathodic electrolyzed lead conductor was washed with running water and dried in a constant temperature bath at 100°C for 180 seconds, thereby obtaining a lead conductor with a conductive coating in which the ratio of the number of chromium atoms contained in the chromium hydroxide in the outermost surface of the conductive coating to the number of chromium atoms contained in the trivalent chromium compound is 0.53. Otherwise, a lead for a non-aqueous electrolyte battery was obtained in the same manner as No.2.

[0157] [Experiment No. 12]

[0158] In the formation of the conductor coating, chromium chloride hexahydrate (5.0 g / L), potassium formate (170 g / L), and calcium chloride (5.0 g / L) were mixed in pure water to obtain a surface treatment solution. The lead conductor was immersed in the surface treatment solution at 45°C and subjected to a current density of 10 A / dm³. 2 Cathodic electrolysis was performed for 30 seconds. The cathodic electrolyzed lead conductor was washed with running water and dried in a constant temperature bath at 100°C for 180 seconds, thereby obtaining a lead conductor with a conductive coating in which the ratio of the number of chromium atoms contained in the chromium hydroxide in the outermost surface of the conductive coating to the number of chromium atoms contained in the trivalent chromium compound is 0.38. Otherwise, a lead for a non-aqueous electrolyte battery was obtained in the same manner as No.2.

[0159] [Experiment No. 13]

[0160] The substrate used as the lead conductor was an oxygen-free copper plate (C1020) with a length of 100 mm, a width of 45 mm, and an average thickness of 0.2 mm. As a pretreatment, the substrate was immersed in a sodium hydroxide aqueous solution (40 g / L) at 25°C, with a current density of 1.0 A / dm³. 2 Cathodic electrolytic degreasing was performed. The degreased substrate was then rinsed with running water.

[0161] Next, the cleaned substrate was acid-activated by immersing it in a 10% by mass sulfuric acid aqueous solution at 25°C for 30 seconds. The acid-activated substrate was then rinsed with running water. No further processing with nickel plating solution was performed; otherwise, leads for non-aqueous electrolyte batteries were obtained, similar to No. 3.

[0162] [evaluate]

[0163] (The ratio of the number of chromium atoms in the chromium hydroxide to the number of chromium atoms in the trivalent chromium compound)

[0164] The ratio of the number of chromium atoms in the chromium hydroxide to the number of chromium atoms in the trivalent chromium compound in the outermost surface of the conductive film was determined using X-ray photoelectron spectroscopy (XPS). The XPS measurement conditions are as follows. Based on the steps described above, the ratio of the number of chromium atoms in the chromium hydroxide to the number of chromium atoms in the trivalent chromium compound was calculated from the energy spectrum obtained under the following measurement conditions.

[0165] <XPS Measurement Conditions>

[0166] Measurement equipment: ULVAC PHI Quantera SXM

[0167] X-ray source: AL-Kα

[0168] X-ray source output: 25W, 15kV

[0169] Analysis area: 100μmφ

[0170] Photoelectron fly-off angle: 45°

[0171] Energy: Narrow spectrum 55eV

[0172] Measurement range: 570 eV~582 eV

[0173] Cumulative Time: Time per step: 20ms

[0174] Number of cycles: 10

[0175] (Correction method for binding energy in the energy spectrum)

[0176] The photoelectron spectrum of C1s was measured from 278 eV to 298 eV. The binding energy was corrected by addition and subtraction with the binding energy of the largest peak in the obtained C1s (278 eV to 298 eV) range being 284.8 eV. The same correction was performed for other elements (Cr2p3).

[0177] (Maleic anhydride modification rate of polypropylene)

[0178] The maleic anhydride modification rate of polypropylene was calculated as follows: using a Thermo Fisher "Nicolet 8700" infrared spectroscopy transmission method, based on 1710 cm⁻¹... －1 The mass of the carboxyl group is determined by the peak area, and converted based on the average thickness of the innermost layer using an appropriate standard curve.

[0179] (Evaluation of resistance to non-aqueous electrolytes)

[0180] <Peeling test after electrolyte immersion>

[0181] For Tests No. 1 to No. 13, a peel test was performed after electrolyte immersion. As the electrolyte, a test solution was prepared by mixing ethylene carbonate, diethyl carbonate, and dimethyl carbonate in a 1:1:1 volume ratio and dissolving lithium hexafluorophosphate (LiPF6) to a concentration of 1.0 mol / L. After adjusting the moisture content of this electrolyte to 1000 ppm, the leads of the non-aqueous electrolyte batteries from Tests No. 1 to No. 13 were immersed in the electrolyte and placed in a constant temperature bath at 80°C for 4 weeks. Then, a peel test was performed on Tests No. 1 to No. 13 after electrolyte immersion using the following method: One of the lead conductors and the insulating film of Tests No. 1 to No. 13 was cut and bent 180°, and placed in a tensile testing machine (Shimadzu Corporation "EX-SX"). The cut portion was stretched at a tensile speed of 50 mm / min, thereby evaluating the presence or absence of peeling at the interface between the conductor and the insulating film. The results are shown in Table 1.

[0182]

[0183] As shown in Table 1, in this lead wire for a non-aqueous electrolyte battery, the conductor is covered by a conductor film containing a trivalent chromium compound including chromium hydroxide and a metal element. The innermost layer of the insulating film stacked on the surface of the conductor film is mainly composed of a resin component containing maleic anhydride-modified polypropylene. The ratio of the number of chromium atoms in the chromium hydroxide in the outermost surface of the conductor film to the number of chromium atoms in the trivalent chromium compound is 0.40 or more and 0.85 or less, and the acid modification rate of the resin component is 0.02% by mass or more and 0.50% by mass or less. Tests No. 2 to No. 4, Test No. 6, Test No. 9 to No. 11, and Test No. 13 showed no peeling at the interface between the conductor and the insulating film in the peel test, indicating good resistance to non-aqueous electrolytes.

[0184] On the other hand, in the peel test, peeling was observed at the interface between the conductor and the insulating film in Test No. 1 (where the acid modification rate of the resin component, which is the main component of the innermost layer, is less than 0.02% by mass), Test No. 5 (where the acid modification rate of the resin component exceeds 0.50% by mass), Test No. 7 (where the ratio of the number of chromium atoms contained in the chromium hydroxide in the outermost surface of the conductor film to the number of chromium atoms contained in the trivalent chromium compound exceeds 0.85), and Test No. 8 and Test No. 12 (where the ratio of the number of chromium atoms contained in the chromium hydroxide is less than 0.40), indicating poor resistance to non-aqueous electrolytes.

[0185] The results above demonstrate the excellent resistance of leads for non-aqueous electrolyte batteries to the non-aqueous electrolyte of non-aqueous electrolyte batteries.

[0186] Explanation of reference numerals in the attached figures:

[0187] 1: Lead wires for non-aqueous electrolyte batteries;

[0188] 3: Conductor;

[0189] 4a: One end;

[0190] 4b: The other end;

[0191] 5: Insulating film;

[0192] 6: Innermost layer;

[0193] 7: Second insulating layer;

[0194] 8: First insulating layer;

[0195] 9: Conductive coating;

[0196] 10: Non-aqueous electrolyte batteries;

[0197] 11: sealed in container;

[0198] 13: Sealing part;

[0199] 14: Internal connection leads;

[0200] 15: Soldering Department;

[0201] 25: Metal layer;

[0202] 26: Outermost resin layer;

[0203] 27: Innermost resin layer.

Claims

1. A lead wire for a non-aqueous electrolyte battery, wherein, The leads for the non-aqueous electrolyte battery include: conductors; and An insulating film, having one or more layers, covers at least a portion of the outer peripheral surface of the conductor. The conductor has a conductor film covering at least a portion of its surface. The conductor coating contains a trivalent chromium compound including chromium hydroxide and metallic elements. The ratio of the number of chromium atoms in the chromium hydroxide on the outermost surface of the conductor film to the number of chromium atoms in the trivalent chromium compound is 0.40 or more and 0.85 or less. The insulating film has an innermost layer stacked on the surface of the conductive film. The innermost layer is mainly composed of a resin component containing maleic anhydride-modified polypropylene. The acid modification rate of the resin component is 0.02% by mass or more and 0.50% by mass or less.

2. The lead wire for a non-aqueous electrolyte battery according to claim 1, wherein, The metallic element is nickel, aluminum, copper, or a combination thereof.

3. The lead wire for a non-aqueous electrolyte battery according to claim 1 or 2, wherein, The conductor coating also contains calcium compounds, fluorine compounds, or combinations thereof.

4. The lead wire for a non-aqueous electrolyte battery according to any one of claims 1 to 3, wherein, The average thickness of the conductor film is greater than 1 nm and less than 50 nm.

5. The lead wire for a non-aqueous electrolyte battery according to any one of claims 1 to 4, wherein, The acid modification rate of the resin component is 0.10% by mass or more and 0.50% by mass or less.

6. The lead wire for a non-aqueous electrolyte battery according to any one of claims 1 to 5, wherein, The average thickness of the insulating film is greater than 0.05 mm and less than 0.50 mm.

7. The lead wire for a non-aqueous electrolyte battery according to any one of claims 1 to 6, wherein, The average thickness of the innermost layer is greater than 0.01 mm and less than 0.25 mm.

8. The lead wire for a non-aqueous electrolyte battery according to any one of claims 1 to 7, wherein, The conductor is nickel, nickel-plated metal, nickel-phosphorus alloy metal, aluminum, or aluminum alloy.

9. The lead wire for a non-aqueous electrolyte battery according to any one of claims 1 to 8, wherein, In the photoelectron spectrum of the outermost surface of the conductive film obtained by X-ray photoelectron spectroscopy, the difference A between the photoelectron intensity at 577.3 eV and the background is regarded as the number of chromium atoms contained in chromium hydroxide (III), the difference B between the photoelectron intensity at 576.1 eV and the background is regarded as the number of chromium atoms contained in chromium oxide (III), and the difference C between the photoelectron intensity at 579.8 eV and the background is regarded as the number of chromium atoms contained in chromium fluoride (III). The ratio of the number of chromium atoms contained in the chromium hydroxide to the number of chromium atoms contained in the trivalent chromium compound is set as A / (A+B+C).

10. A non-aqueous electrolyte battery, comprising: sealed into a container; A plurality of non-aqueous electrolyte battery leads as described in any one of claims 1 to 9, configured to extend from the interior to the exterior of the sealed container; and Non-aqueous electrolyte.

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